Antlions (Neuroptera) are a group of sit-and-wait predator insects, with some species further specializing in digging conical pit-traps in the ground in order to catch prey. Studies on antlions’ predators are scarce with only few generalist predators known to feed on them. Here we report for the first time on field observations of antlions’ predation by three scorpion genera. We suggest that scorpions may be common predators of antlions, at least in the hyper-desert environment of southern Israel. The effects of predation risk on the behavior of sit-and-wait and particularly on trap-building predators received little attention in the literature. In light of our observations, we posit that predation risk must be taken into serious consideration in future research of antlions in particular, and sit-and-wait predators in general.
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Nitzan Segev, Efrat Gavish-Regev and Oded Berger-Tal
Colin M. Wright, James L.L. Lichtenstein, Lauren P. Luscuskie, Graham A. Montgomery, Sara Geary, Jonathan N. Pruitt, Noa Pinter-Wollman and Carl N. Keiser
Social spiders are thought to predominantly receive information about their environment through vibrational cues. Thus, group living introduces the challenge of distinguishing useful vibrational information from the background noise of nestmates. Here we investigate whether spatial proximity between colony-mates may allow social spiders (Stegodyphus dumicola) to reduce background noise that might obstruct vibrational information from prey. To do so, we constructed experimental colonies and measured whether the number of spiders in proximity to one another whilst resting could predict the number of spiders that participated in prey capture. Additionally, we exposed spider colonies to five different simulated vibrational cues mimicking prey to determine which cue types spiders were most responsive to. We found that the number of spiders huddled together prior to foraging trials was positively correlated with the number of spiders participating in collective foraging. Furthermore, colonies responded more quickly to pulsed vibrational cues over other types of vibrational patterns. Together these data reveal that both social interactions and prey cues shape how social sit-and-wait predators experience and respond to their environment.
Vesna Klokočovnik, Eva Veler and Dušan Devetak
The study focused on the behaviour of sit-and-wait antlion larvae in interspecific interactions. Antlion larvae usually occur in clusters with a high density of individuals; therefore, competition can be intense. We observed two abundant antlion species, E. nostras and M. formicarius, which co-occur in some habitats. In a simple habitat choice experiment where substrates differed according to sand particle size, we found that E. nostras exhibited dominance over M. formicarius. Most E. nostras larvae remained in the more suitable substrate and constructed pits, while all the M. formicarius larvae moved out of the suitable area, and did not build pits. In the second experiment, we observed the characteristics of the pit-fall traps and scored the occurrence of larval relocation in relation to interactions and in the control group, where larvae were kept in containers separately. In interactions, the larvae of E. nostras constructed smaller pits, but pit enlargement was greater in comparison to the control group. M. formicarius larvae constructed similar sized pits in both groups; however, enlargement was greater in the control group. Relocation of larvae occurred only during interactions. In direct interactions, we found 15 behavioural patterns, which are described in detail for the first time. In the presence of a competitor, larvae showed intense territorial behaviour. We recorded several behavioural patterns during larval confrontation, and interestingly, intraguild predation rarely occurred. In most cases, E. nostras larvae outcompete M. formicarius, which was evident from the larger pits and the rate of pit-construction.
Sean J. Blamires
Traps are rarely used by animals, despite the plausible benefits of broadening the number and diversity of prey that sit-and-wait foragers might be able to capture. The most well-known trap building sit-and-wait foragers are among the invertebrates, i.e. antlions, wormlions, glow worms, caddisflies, and spiders. A plausible hypothesis for the paucity of trap building by other animals is that biomechanical limitations render them inefficient or ineffective at catching sufficient prey. Here I examined the literature to make a valued judgement about the validity of this hypothesis. It appears that antlion and wormlion pit traps cannot catch and retain the largest prey they might expect to encounter. Arachnacampa glowworm traps are functionally efficient, facilitated by the animal’s bioluminescence. Nevertheless they only function in very moist or humid conditions. Caddisfly traps rely on flowing water to be able to capture their prey. Spiders are exceptional in developing a wide range of prey trapping strategies, from webs with dry adhesives, to sticky orb webs, to modified orb webs, e.g. elongated “ladder” webs, to webs with additional structures, and web aggregations. Some spiders have even redesigned their webs to minimize the high prey escape rates associated with web two dimensionality. These webs nevertheless are constructed and used at specific costs. While hard data across all of the invertebrate predators is lacking, there seems to be credence in the hypothesis that the biomechanical limitations placed on trap functionality can explain their limited use among animals.
Maja Peryga and Krzysztof Miler
Some terrestrial leeches mate by entwining the anterior ends of their bodies and then copulating. Here, we report first observations of a similar behavioral pattern in Haemadipsa picta terrestrial leeches from Malaysian Borneo. However, because the observed pattern can be easily induced artificially with no clear evidence of copulation, we suggest that it may serve another function, particularly in H. picta. We hypothesize that the wrestling behavior, as we term it, may be a ritualized aggressive display driven by competition for ambush location. Haemadipsid fauna of the region is poorly studied, therefore our observations extend limited knowledge about these leeches and open interesting research avenues for the study of the wrestling behavior.
Aaron M. Ellison
Carnivorous plants are pure sit-and-wait predators: they remain rooted to a single location and depend on the abundance and movement of their prey to obtain nutrients required for growth and reproduction. Yet carnivorous plants exhibit phenotypically plastic responses to prey availability that parallel those of non-carnivorous plants to changes in light levels or soil-nutrient concentrations. The latter have been considered to be foraging behaviors, but the former have not. Here, I review aspects of foraging theory that can be profitably applied to carnivorous plants considered as sit-and-wait predators. A discussion of different strategies by which carnivorous plants attract, capture, kill, and digest prey, and subsequently acquire nutrients from them suggests that optimal foraging theory can be applied to carnivorous plants as easily as it has been applied to animals. Carnivorous plants can vary their production, placement, and types of traps; switch between capturing nutrients from leaf-derived traps and roots; temporarily activate traps in response to external cues; or cease trap production altogether. Future research on foraging strategies by carnivorous plants will yield new insights into the physiology and ecology of what Darwin called “the most wonderful plants in the world”. At the same time, inclusion of carnivorous plants into models of animal foraging behavior could lead to the development of a more general and taxonomically inclusive foraging theory.
Inon Scharf, Yehonatan Samocha and Noa Katz
When choosing among several potential habitats, animals should strive to choose the habitat that provides the highest fitness. When animals choose habitats that do not provide the best possible fitness, there is a mismatch between habitat preference and performance. A common reason is that of limited information or perceptual range. Sit-and-wait predators are particularly deficient in information, due to spending most of their time in ambushing prey and, when they do travel, they cover only short distances. Here, we studied the effect of placing pit-building wormlions at a short distance from their preferred microhabitats, on the likelihood of them choosing it. When placed on the border between deep and shallow sand, fine and coarse sand, or dry and wet sand, wormlions chose the former in each case in vast proportions. However, the ability of wormlions to recognize and/or choose favorable habitats decreased sharply with distance, suggesting that they are limited in their perceptual range. We next examined whether wormlions relocate their pits following a continuous disturbance arriving always from the same side. Although they did so, their movement direction was unrelated to the direction of the disturbance. The preference of wormlions for a favorable, shaded microhabitat depended greatly on the location of a conspecific competitor: the favorable microhabitat was more attractive for wormlions when a competitor was more distant from it than when the competitor was located on the border between the favorable and unfavorable microhabitats. Our findings support previous studies indicating the limited perceptual range of pit-building predators.
Alejandro G. Farji-Brener and Sabrina Amador-Vargas
The physical structures built by animals are considered extended phenotypes that reflect how organisms make decisions and deal with changes in their biotic and abiotic environment. We summarize the results of several studies on Myrmeleon crudelis, a neuropteran larva that digs pit-traps in the soil to capture small arthropods (mostly ants) in the tropical dry forests of Costa Rica. Specifically, we showed how this species responds to varying biotic and abiotic conditions with changes in the design and/or location of its pit traps. Several experiments and field comparisons indicate that: 1) antlions adjust the pit design according to the abundance and type of prey. When prey is scarce, antlions increased trap diameter, an architectural adjustment that enhances the probability of prey encounter. Antlions that experienced high prey abundance, but the prey easily escaped, then increased pit depth, an adjustment that increases the chance of prey retention; 2) soil compaction strongly reduced pit-trap size and abundance; 3) antlions preferred soils with high proportion of fine-particle size to build pits. In fine-grained soil, pit-traps are larger and more efficient to capture prey than traps in coarse-grained soils; and 4) pit-traps may also be affected through indirect effects of soil structure and vegetation cover. Areas with fine-soil presented less plant cover, and plant cover could be beneficial for antlions because it acts as a shelter against direct sunlight and rainfall, or it may represent a cost because it is a source of leaflitter falling in the pits. The works summarized here how trap-building predators can exhibit considerable flexibility in trap construction in response to various biotic and abiotic factors, emphasizing how the study of extended phenotypes can be a useful approach to better understand the flexibility of foraging behaviors.
Dulce Rodríguez-Morales, Helena Ajuria-Ibarra, Laura T. Hernández-Salazar, Víctor Rico-Gray, José G. García-Franco and Dinesh Rao
Predation is one of the main interactions between organisms and one of the primary selective agents for their survival. Both prey and predators have developed different strategies and characteristics that allow them to be conspicuous or go undetected. In sit and wait predators, their shape and appearance are important factors that allow them to remain undetected by their potential prey. Sit and wait predators such as crab spiders are difficult to identify when they sit on flowers or areas of flowers with colors similar to the color of their bodies. In this study, we aimed to determine if insects can recognize the morphology and color polymorphism of crab spiders by evaluating the response of flower visitors. We quantified the visits and approaches of floral visitors to the flowerheads of Palafoxia lindenii with spider morphology and color polymorphism treatments. Our results show that insects in general, and bees in particular, avoid visiting flowers with a real spider or a spider model and visit vacant flowers more frequently. In the case of the color polymorphism, insects approached flowerheads with spiders with a similar frequency independently of the color of the spiders, but did not visit them. Insects appeared to identify spiders through their morphological characteristics rather than their color characteristics, since flower visitors did not discriminate between the evaluated spider colors (white, lilac, and purple). This study emphasizes the differential response of different insect prey to the presence, color, and morphology of sit and wait predators.
The sand viper Cerastes vipera can employ one of two distinct foraging modes, the widely foraging or sit-and-wait mode, depending on the interplay between external and internal factors. Here, I illustrate how tracking methods can be used to evaluate the relative usage of each of the two foraging modes by the sand viper. Foraging theory models generally refer to the time invested in foraging as the main indicator of the energy invested in foraging. I suggest that tracking and counting print marks on trails offer a more precise method of estimating foraging costs in the field. I model the benefits and costs of the viper employing each of the two foraging modes using tracking data, and discuss how it can be used to decipher its foraging mode. I present a measurement approach by which to assess the relative usage of different foraging modes. I contend that the proposed tracking methods and their analysis should prove to be equally applicable to other animals that leave print marks on sand or snow.
Bharat Parthasarathy and Hema Somanathan
Dispersal is inherent to all living organisms. Sit-and-wait predators such as social spiders, with their sedentary lifestyles, present an intriguing and underexplored case to examine the proximate and ultimate reasons for dispersal. Though a reduction in dispersal tendencies must accompany the evolution of sociality in spiders, a fraction of the colony may disperse in groups or individually in many species. Such group or solitary dispersal by female social spiders in specific life stages, can lead to colony fission or colony foundation. Males move between colonies, however, there are no direct estimations of male dispersal distances for any species. The structured populations and high inbreeding within colonies suggest that dispersal events occur over limited spatial scales and may be mediated by extrinsic and intrinsic factors. Future studies exploring complex relationships between environmental variables, phenotypes of individuals, colony state and dispersal are advocated. Another area of interest is probing the dispersal process itself to understand the mechanisms of information transfer between individuals at the onset of dispersal. This involves designing studies to examine how break-away groups reach a consensus on when to disperse and where to go.
G. Brabata, C. Battisti, R. Carmona and C.A. Sánchez-Caballero
The Chametla wetland is used by shorebirds as a stopover site during their autumn migration and it is also an important breeding area for several species of waterbirds. The objective of this work was to compare the bird assemblages in Chametla wetland during three sampling periods: 1) 1991–1992; 2) 1997–1998 which was subjected to El Nino Southern Oscillation (ENSO) climate conditions and 3) 2005–2006. Bird communities were characterized in terms of species composition and diversity, using similarity analysis. Bird assemblage composition differed across years and seasons. Seasonal variations in composition and diversity were related to the presence/absence of phenological-characterized species (migratory vs. wintering species). The highest species richness was recorded under the ENSO period (1997–1998). We observed a sharp decrease in shorebird numbers, with evident stress at the assemblage level throughout the entire study period. There seems to be a transition of the bird assemblages from shorebird dominance to a dominance by long-legged wading birds and waterfowl species, which could be related to water level variation and changes in the quality/availability of food in the intertidal zone. The joint pressures of regional climate variation combined with local anthropogenic perturbations may lead to changes in bird assemblage in the Chametla wetland.
Zhen Zhang, Lichao Wang, Jing Liu, Zhaorong Dong, Wei Xu and Shiping Wang
Understanding the reproductive response of host plants to herbivores is important in grazing ecology and grassland management. Simulated grazing experiments were conducted to determine the influence of different grazing intensities on reproductive performance of a shrub, Caragana microphylla Lam. The total leaf mass, total flower mass, total flower mass allocation, and single flower mass allocation decreased with increased grazing intensity. The total spine mass, single flower mass and total spine mass allocation increased with increased grazing intensity. The stem mass, stem mass allocation and total leaf mass allocation had not significant change with the increasing grazing intensity. Under heavy grazing treatments, the host plants significantly decreased their investment in reproduction and increased investment in physical defense organs. Although there were no significant differences in the number of ovules among different grazing intensities, herbivory negatively affected reproductive performance, including the number of flowers, the number of pollen grains per flower, the number of ripe seeds and the rate of pod-set in host plants. These results indicate that there are trade-offs among vegetative and reproductive and defensive organs. Compared with male reproduction, female reproductive performance was less sensitive to herbivory and grazing intensity. Moreover, pollen grains from heavily browsed plants seemed to be less likely to sire pods and ripe seeds than those from unbrowsed plants, indicating that herbivory not only decreased pollen production, but also adversely affected pollen performance.
Adiv Gal, David Saltz and Uzi Motro
The effect of food supplement to Lesser Kestrel (Falco naumanni) nests during the nestling period (from hatching to fledging) was studied in two nesting colonies in Israel – Alona and Jerusalem. Our hypothesis, based on diminishing returns considerations, was that food supplement will have a greater effect on fledgling success in the food-limited, urban colony of Jerusalem, than in the rural colony of Alona. Indeed, food supplement had a significantly positive effect on breeding success in both colonies. However, and contrary to our prediction, the decrease in chick mortality between supplemented and control nests in Jerusalem was not larger than in Alona (actually it was numerically smaller, albeit not significantly so). This implies either that additional factors, possibly urbanization associated, other than food limitation, might be responsible for the difference in nesting success of Lesser Kestrels between Alona and Jerusalem, and/or that the amount or the nutritional quality of the additional food provided to supplemented nests (three mice per chick per week), was not enough.
Xinguang Yang, Xilai Li, Mingming Shi, Liqun Jin and Huafang Sun
Replacement of topsoil to an appropriate depth is one of the key methods for ecological restoration. The objective of this study was to investigate the effects of topsoil replacement depth on vegetation and soil properties, and to identify the optimum soil depth for reclamation of coal mine spoils in a cold alpine mining area. We sowed 3 herbaceous species after coal mine spoil heaps were treated with topsoil to 3 depths (0, 20‒25, 40‒45 cm). The variations in vegetation community structure, plant growth, soil properties were measured at different replaced topsoil depths. The correlations between plant and soil properties were analyzed statistically. The results showed species richness, diversity and evenness were not significantly different among different depths of topsoil (P > 0.05). Vegetation coverage, density, height and aboveground biomass increased significantly (P < 0.05) with increasing topsoil depth. Soil properties did not change significantly with increasing topsoil depth (P > 0.05), but soil organic matter was significantly higher at 40‒45 cm topsoil depth than at other two depths (P < 0.05). All soil properties, with the exception of total potassium, were positively correlated with the plant growth parameters. The 40‒45 cm topsoil depth of replacement should be considered as effective method in reclaiming coal mine spoils. The use of both topsoil replacement to a depth of 40‒45 cm and sowing of suitable herbaceous seeds is found to be an effective restoration strategy. Additionally, fertilization might be used as a substitute for artificial topsoil replacement to improve soil quality and speed up revegetation process by the positive plant-soil interactions.
Sundararaj Vijayan, Lotan Tamar Tov Elem, Reut Vardi, Anjala Pyakurel and Zvika Abramsky
Behavioural innovations play an important role in animal ecology and evolution. We report a case of little egret using its beak dips as a tool to lure and catch prey goldfish in an artificial environment designed to test predator–prey behavioural foraging games. The egret mimicked the food pellets falling into the pool from a mechanical feeder that fed the goldfish at regular intervals. The falling pellets created ripples in the water that acted as a cue for the prey goldfish to come out of the cover and feed on the floating pellets. The egret learned this phenomenon through time and used its beak dips to create ripples and attract the prey outside. The egret preferably used the location of the feeder in the pool to carry out its beak dipping attempts and maximize its fish capture success. The egret attempted this behaviour more in the largest cover that provided the best refuge to the prey goldfish. The egret beak dipping attempts to lure the prey goldfish out of the cover declined through experimental time as well as with increasing prey kills. As the beak dipping behaviour did not result in a high capture rate of fish, the egret subsequently reduced its attempts through time. This case study illustrates that foraging innovations can occur through learning in laboratory conditions containing a novel but artificial environment.
Rida Sultanova, Ildar I. Gabitov, Yulai A. Yanbaev, Fitrat G. Yumaguzhin, Maria V. Martynova, Ivan V. Chudov and Varys R. Tuktarov
The management of beekeeping on forest lands is a vivid manifestation of the multifunctional use of forests, which is based on its target cultivation. The work shows the development of beekeeping, identifies factors affecting the sustainable development of this industry, sets priorities for increasing the efficiency of utilization of forest honey resources of the Southern Urals, including the main melliferous - Tilia cordata Mill. The nature and characteristics of the influence of weather and climatic factors on the growth of bee colonies, their physiological state, composition, age representation of natural melliferous woody plants, the onset dates and the duration of their flowering were determined. It was found that, of the silvicultural and inventory indicators, the composition and age, density and type of forest most strongly influence the yield of honey. The activities of forest care are close to them in terms of importance. A system of organizational measures has been proposed, through which high efficiency of using forest feed resources and sustainable development of beekeeping can be achieved: keeping an optimal number of bee colonies in an apiary - up to 150 hives, based on providing one bee colony of 50-60 thousand individuals with at least 130 kg of nectar; the location of apiaries in the 3-kilometer zone of growth of forest melliferous plants, taking into account the productive emergence of bees in the 2.5-3.0 km; establishing clear nomadic routes based on a geobotanic inventory of forest and agricultural melliferous plants. Increasing the target indicator - the nectar productivity of forests without a gap in their use both in space and in time - can be achieved by growing multi-tiered forests of different age from Tilia cordata Mill.
Konul G. Hasanova
The purpose of this research was to study the dynamics of melatonin, insulin, adrenaline and glucose in the blood of rabbit kits (prior and subsequent to prenatal hypoxia) at various stages of fetal growth and development; to study the ability of kits to withstand physical exertion of various intensity and duration in light and dark. The study of hypoxia exposure factors, photoperiodic factors and methods for correcting its effects is one of the pressing issues currently facing experimental and clinical physiology. In this context, it is important to study the effect of prenatal hypoxia on hormones synthesizing and expressing principles in the early periods of postnatal ontogenesis. This research shows that melatonin level decreases with increasing insulin and increases with decreasing insulin in animals of different ages kept under conditions of constant light and constant darkness, while the level of adrenaline decreases at physical exertion, but increases with a decrease in melatonin. This research confirms the inverse relationship between the levels of melatonin and insulin and between the levels of melatonin and adrenaline. Kits being in constant darkness have increasing melatonin, which by contrast decreases under conditions of constant light.
Roberto Isotti and Mario Monacelli
Management algorithms of protected areas are widely used to identify potential networks of natural reserves that meet pre-established ecological requirements, such as a specific habitat percentage or a specific number of populations, while minimizing the related costs. Here we present a comparison of priority conservation maps of a protected area in central Italy, generated using different methods (i.e., Marxan, Marxan with Zones, Zonation, and directly overlapping the bird data with the vegetation type in the study area), based on an eight-year data set describing bird communities in the Circeo National Park. The generated maps can be used as a starting point when working with stakeholders involved in the management of this area. Our cartographic comparison illustrated that in the majority of the cases priority areas overlapped (the proportion of overlap was greater than 80% of the area size), affirming that the methods are equivalent. However, there were also divergent cases (the proportion of overlap was 0% of the area size), suggesting differential sensitivities of the four compared methods.
Facundo Xavier Palacio, Mariano Ordano and Santiago Benitez-Vieyra
The use of multiple regression analysis to quantify the regime and strength of natural selection in nature has been an influential approach in evolutionary biology over the last 36 years. However, many studies fail to report the protocol of estimation of selection coefficients (selection gradients) and the specific model assumptions, thus failing to verify and reproduce the estimation of selection coefficients. We present a brief overview of the Lande and Arnold’s approach and a step-by-step R routine to aid researchers to perform a verifiable and reproducible regression analysis of natural selection. The steps involved in the analysis include: (1) assessing collinearity between phenotypic traits, (2) testing normality of model residuals, and (3) testing multivariate normality of phenotypic traits. We also performed a series of simulations to test the effect of non-symmetrical (skewed) phenotypic traits on the estimation of linear selection gradients. These showed that the bias in the linear gradient increased with increased skewness in phenotypic traits for the quadratic model, whereas the linear gradient of a model with only linear terms was nearly independent of trait skewness. If none of the above assumptions are met, selection gradients need to be estimated from two separate equations, whereas standard errors must be computed using other methods (e.g. bootstrapping). We expect that the procedure outlined here and the availability of analytical codes motivate the verifiability and reproducibility of the Lande and Arnold’s approach in the study of microevolution.
Edith Katsnelson Ilan, Orli Bobek, Adiv Gal, David Saltz and Uzi Motro
We studied Lesser Kestrels’ (Falco naumanni) conditional nest-site fidelity, i.e., fidelity that depends on the outcome of the previous nesting attempt in that site. In particular, we were interested in examining whether individual kestrels practice a Win–Stay/Lose–Shift (WSLS) strategy towards their nest-sites; that is, does the tendency to use the same nest-site increase following a successful nesting season, but decrease following a failure. For that purpose, we documented the use of nest-sites by Lesser Kestrels and the breeding success in these sites during 1998–2003 in the city of Jerusalem (Israel). We found that while Lesser Kestrels do not practice WSLS strategy towards their nest-site, the males (but not the females) do so towards their sub-colony – they tend to stay in the same sub-colony if their nesting was successful, whereas they tend to migrate to a different sub-colony after failure. A possible explanation to this sexual difference in WSLS behavior can arise from the fact that changing a sub-colony entails a change of hunting area. The male, being the main food provider in the Lesser Kestrel, may be more sensitive to this opportunity.
Ofer Ovadia, Inon Scharf, Erez David Barkae, Tanya Levi and Yehonatan Alcalay
Co-occurring species often compete with each other directly and indirectly. Intra-guild predation (IGP) is an extreme manifestation of direct competition, which involves the attack, killing and eating of potential competitors. We studied the competitive interactions between two pit-building antlion species that co-occur in the Israeli desert: Myrmeleon hyalinus residing in the more productive sandy soil, and Cueta lineosa solely inhabiting poorer loess soils. To understand the mechanisms driving C. lineosa away from the more productive habitat, we explored the factors triggering IGP of one antlion species on the other. We tested whether IGP is affected by soil type, depth and temperature. IGP was asymmetrical with M. hyalinus preying on C. lineosa, and it intensified as the size difference favoring the former increased. Interactive rather than additive effects governed IGP, which was lowest in sandy soil combined with low temperature, and highest in shallow loess soil. C. lineosa possesses a smaller head and thorax relative to its abdomen compared to M. hyalinus, providing a possible explanation for the advantage of M. hyalinus in direct competition. We then focused on the weaker competitor, C. lineosa, examining how it copes with competition induced by M. hyalinus. Both the growth and survival rates of C. lineosa declined in the presence of M. hyalinus. The asymmetrical IGP C. lineosa experiences from M. hyalinus combined with its competitive inferiority may explain why it is mostly found in poor habitats, while its intra-guild competitor is abundant in the more productive habitats.
The remarkable diversity of antlions in the Afrotropical region is counterbalanced by the scarce knowledge of their biology and ecology. In particular, their larval stages are largely unknown and the morphology of African pit-building species was never investigated in detail. The larvae of three pit-building species attaining a wide distribution across the whole continent, namely Myrmeleon caliginosus, M. obscurus and M. quinquemaculatus are described, illustrated and compared with congeners for the first time. Moreover, M. caliginosus is reported for the first time from Namibia, notably extending the known range of this antlion, with implications on the taxonomy and the identification of African Myrmeleon species. The larvae of these three species highlight the overall conservative morphology across the whole genus, differing in relatively minor characters such as size, proportions, pattern and chaetotaxy.
Shai Meiri, Amos Belmaker, Daniel Berkowic, Kesem Kazes, Erez Maza, Guy Bar-Oz and Roi Dor
Faunal lists are important tools in ecology, biogeography, and conservation planning. Such lists can identify gaps in our knowledge of the distribution and taxonomy of regional faunas, and highlight issues needing further study. We present an up to date list of all land vertebrates occurring in Israel. We identify 786 species, of which 551 are birds, 130 are mammals, 97 are reptiles and eight are amphibians. Of these 369 species breed in Israel (including reintroductions), 199 (mostly birds) are regular visitors and 182 are accidental. Fourteen other species are invasive, and 22 species are extinct. We identify issues with the taxonomy and status of several species, and note recent developments in our understanding the Israeli land vertebrate fauna.
Xin Yin, Wei Qi and GuoZhen Du
A growing body of evidence from diversity-manipulation and natural studies suggests that the stability of community productivity increases with biodiversity; however, few studies have researched this relationship in a non-weeded grassland. To clarify this issue, we established an artificial grassland in 2003 using three common species, Elymus nutans, Festuca sinensis and Festuca ovina, which included seven different community structures (three monocultures, three two-species mixtures and one three-species mixture based on sown species) and two nutrient addition treatments (non-nutrient addition and nutrient addition). Data was collected over a three-year period (2011–2013). Our results showed that the sowing species modified realized species richness (i.e. the number of total species we observed in a community) and species evenness, but had negligible influences on community- and population-level stability. Furthermore, all of these variables were reduced by nutrient addition. These dynamics did not alter the positive influence of realized species richness on community stability, but restricted the stable effect of evenness because this effect was only significant under nutrient addition condition. The potential mechanisms underlying these processes were statistical averaging and species asynchrony, rather than overyielding effect. Conversely, population stability decreased with realized species richness in non-nutrient addition treatments. We conclude that biodiversity contributed to community- and population-level stability even in non-weeded experiment. This process resulted from different mechanisms that observed in weeded experiments. Further studies in other ecosystems (e.g. aquatic ecosystem) are needed to find a more general conclusion.
Chaobin Zhou and Wei Gong
In the arid region of northwest China, H. ammodendron has become the main pioneer species for the restoration of plant communities. However, the breeding system of the plant remains unknown. The floral dynamics and the breeding system characteristics of H. ammodendron were investigated in this study, using a bagging experiment. The results show that anthesis lasted about 22 d. The longevity of individual flowers was 14.1 d. Stigma receptivity lasted about 6 d and there were relatively long periods for the meeting between stamen and stigma. Anther height was slightly greater than that of the stigma. The outcrossing index was 2 and the pollen-ovule ratio was 64,815. The H. ammodendron mating system can be described as a mixed mating system with facultative apomixis; pollination is not necessary for reproduction. The mixed mating system with facultative apomixis could guarantee the reproductive success of H. ammodendron in severe desert conditions with sparse pollinators.
Justin R. St. Juliana, Burt P. Kotler, Berry Pinshow and Noga Kronfeld-Schor
We studied the influence of manipulating predation risk on Allenby’s gerbil ( Gerbillus andersoni allenbyi) held in a large, outdoor enclosure. We measured giving up densities (GUDs), apprehension, time allocation to foraging, harvest strategy (grab and go (GAG) vs. eat at tray (EAT)), and fecal cortisol concentration. First we established the time necessary for cortisol and corticosterone concentrations to change significantly from baseline after a stressful experience. To do this we collected feces from gerbils 2, 4, 6, or 8 hours after being handled (treatment) or not (control). After 8 h, fecal cortisol, but not corticosterone, concentration was significantly higher in treatment animals. We used the results from the hormone time course experiment to design the predation experiment. We used a dog, trained to harass gerbils, to increase predation risk for the gerbils. We predicted that fecal cortisol concentrations would increase directly in the face of predation risk, or indirectly, due to reduced foraging time because of perceived predation risk that, in turn, leads to increased hunger levels. As predicted, in the presence of a predator, GUDs were higher, time allocation lower, and GAG foraging was used more in treatment animals than in controls, but we found no change in apprehension. There was no difference in cortisol concentration between predator present and no-predator treatments. However, individuals that tended to have higher average fecal cortisol concentrations also tended, on average, to spend more time foraging. This indicates a relationship between stress hormones and optimal foraging. This relationship is potentially causal. While nightly changes in behavior may not be related to stress hormones, over course time scales, stress hormones may be driving gerbils to forage more.
Justin R. St. Juliana, Jocelyn L. Bryant, Nadja Wielebnowski and Burt P. Kotler
We evaluated the suitability of a corticosterone enzyme immunoassay (EIA) to monitor excretion of fecal glucocorticoid metabolites (FGM) in response to Adrenocorticotropic hormone (ACTH) and saline injections in three desert rodent species (Gerbillus andersoni allenbyi (GA), Gerbillus nanus (GN), and Gerbilis piridium (GP). We exposed 24 gerbils (N = 9 for GA, N = 7 for GN, N = 8 for GP) to an ACTH and a saline injection at different times. Fecal samples were collected hourly for 24 hours after injection. The average starting concentration (baseline) FGM concentration was 797 ng/g for GA, 183 ng/g for GN, and 749 ng/g for GP. The average peak concentration was 2377 ng/g for GA, 589 ng/g for GN, and 1987 ng/g for GP. We were able to provide a physiological validation for the chosen assay in GAs and GPs, however, our results for GNs were less clear. We found an increase in FGM concentrations on average after 5.5 hours in GA, 3.1 hours in GN, and 3.8 hours in GP. We found a peak in FGM concentration on average after 8.8 hours in GA, 5.6 hours in GN, and 10.3 hours in GP. We determined that FGM concentration returned to starting value on average after 14.4 hours in GA, 9.1 hours in GN, and 15.1 hours in GP. The outcomes of this study can help establish trapping protocols and time frames for FGM monitoring of these wild small mammal populations. The time course for excretion of FGM is similar between the species in this study, and comparable to some non-desert rodents. We found high variation in the time course of excretion within species. This variation needs to be taken into account when monitoring stress responses in the field. By assessing adrenocortical activity using FGM monitoring, stress responses to varying ecological and environmental factors can be reliably examined in the field.
Rachel Schwarz, Gavin Stark and Shai Meiri
The south-facing slopes in canyons, oriented along an east-west axis north of the equator, are often hotter and drier than north-facing slopes, promoting differences in the biotic and abiotic characteristics of the opposing slopes. We studied how diversity and abundance patterns have changed in Oren stream (Carmel Mountains, Israel) during the last 25 years. We tested whether temperature and habitat preferences of reptiles affected observation frequencies, to assess potential effects of global warming on the reptiles. We compared the results of a 1993–1994 survey in Oren stream to a survey we conducted during 2017–2018, using similar methods, survey area and effort. Species composition and abundance in Oren stream did not significantly change between studies, but the proportion of observations differed significantly across slopes for four out of the six most abundant species. The number of observations increased monotonically with increasing temperatures on the south-facing slope, but decreased on the north-facing slope above a temperature of 22°C. The major biome species inhabit globally was unrelated to the number of observations across slopes or studies, but species inhabiting warmer ranges were more frequently observed in the current survey. Our results suggest that as global temperatures rise, reptile species which can tolerate higher temperatures, and those which can avoid the hottest temperatures of the day, may be able to cope better. These results however may also derive from better detection ability of some species over others between study teams.
Aitzhamal S. Mussina, Gaukhar U. Baitasheva, Meruyert S. Kurmanbayeva, Galia J. Medeuova, Adilhan A. Mauy, Elmira M. Imanova, Akbota Zh. Kurasbaeva, Zaida S. Rachimova, Yerlan S. Nurkeyev and Kanat Orazbayev
Reaction of the plant body in polluted conditions allows estimating the anthropogenic impact on the environment. The aim of this work is to study anatomical and morphological changes of juniper in terms of the polymetallic pollution of the environment and under the influence of heavy metals. The assessment of some heavy metals impact on juniper was conducted after the planting of seed samples in the soil and obtaining good germination. The juniper has been treated with heavy metal solutions in the lab for 4 months. To determine the anatomical structures of the leaves of the juniper, the samples were fixed by the Strasburger-Fleming method. Under the influence of urban air, negative anatomical and morphological changes of juniper were discovered, the significant increase in the thickness of the needles, the thickness of the conducting bundle and the thickness of the epidermis was noted, that, apparently, provides higher resistance to man-induced pollution. It is shown that the process of environmental restoration can be done due to self-purification by using adsorption properties of leaves of woody plants, for example juniper, that is able to absorb heavy metals (lead, cadmium, cobalt, chromium, nickel, zinc and copper) from urban air. It was first discovered that the effects of heavy metals (lead and nickel) as the nutrient medium leads to the significant changes of the leaves’ anatomical structure (the swelling of the phloem, some decondensation in the mesophyll). The research results allow recommending the juniper for phytoremediation, bioindication and landscape gardening of cities and settlements in different countries.
Zulkiya Namazbaeva, Sharbanu Battakova, Lyazat Ibrayeva and Zhanbol Sabirov
Risk factors in Aral Sea region include toxic metals that competitively interact with essential elements influencing their metabolism, affecting metabolic and cognitive functions. According to epidemiological data, cerebrovascular disease and thyroid function abnormality are the leading disorders. Cognitive and metabolic disorders are considered as risk factors in cerebrovascular diseases. Thus, the objective of current work was to determine the metabolic and cognitive state of people in Aralsk, associated with an imbalance of essential trace elements and find correlation between toxic metals load and psychoemotional status. 275 people between the ages of 21 and 45 years were involved. In evaluating cognitive state, a decrease in short-term memory for numbers and an increase in depression among subjects was found. An inverse correlation between the copper level in blood and short-term memory for numbers, between depression and iodine level in blood, between the zinc level in blood and the “attentional capacity” was also found. The results showed a significant metabolic stress among subjects during adaptation to a high chemical load. Data represent a cross-sectional age-dependent review of metabolic and cognitive processes and microelement metabolism among population, living in the Aral Sea region for a long time.
Yong-hua Zhu, Sheng Zhang, Biao Sun, Xiao-kang Xi, Yu Liu and Xiao-hong Shi
Quantification of the pattern and spatial distribution of soil organic carbon (SOC) is essential to comprehending many eco-hydrological processes. To obtain a better understanding of the spatial variability of SOC in a typical farming-pastoral zone, 270 soil samples were collected at 45 sampling sites from every 20 cm soil layer. Semi-variance function theory and ordinary Kriging interpolation were applied to identify the spatial variability of SOC. The results showed that SOC in the area was relatively low and decreased with depth and from the basin edge to the centre with a measured mean content of 0.07–0.65 g/kg. The strongest variability in the zone in the top soil layer (0–40 cm) was in the centre part of the zone, which was supposed to be the most concentrated area of human activities in the zone. As soil depth increase, the degree of variation of SOC decreased. Gaussian, exponential, and spherical models were suggested to successfully simulate SOC in different soil depth zones. The spatial distribution of SOC showed strong variability in the same soil depth zone, with a nugget to sill ratio of less than 14% and a range of 30–160 km.
Jong Myong Park, Ji Won Hong, Jin-Soo Son, Ye-Ji Hwang, Hyun-Min Cho, Young-Hyun You and Sa-Youl Ghim
This review focuses on the state of research on the microbial resources of Dokdo, Korea, as a strategy for securing national microbial resources. In the Korean peninsula, studies aimed at securing microbial resources are carried out across diverse natural environments, especially in the Dokdo islands. Until 2017, a total of 61 novel microbial genera, species, or newly recorded strains have been reported. Among these, 10 new taxa have had their whole genome sequenced and published, in order to find novel useful genes. Additionally, there have been multiple reports of bacteria with novel characteristics, including promoting plant growth or inducing systemic resistance in plants, calcite-forming ability, electrical activation, and production of novel enzymes. Furthermore, fundamental studies on microbial communities help to secure and define microbial resources in the Dokdo islands. This study will propose several tactics, based on ecological principles, for securing more microbial resources to cope with the current increase in international competition for biological resources.
Corrado Battisti and Francesca Marini
We report data on the effects of coppice management on breeding birds in paired oak woods of central Italy using a Before-After-Control-Impact sampling design, hypothesizing that this practice strongly affect abundance, richness and diversity at community level. Using point count method, we obtained first evidence of a coppice management effect acting as a stressor on the breeding bird assemblage structure. We observed a significant decrease in averaged species richness and abundance in coppiced areas before and after the coppicing practices, differently from the control area. Analogously, regression lines derived by species frequencies in diversity/dominance diagrams showed a different trends when comparing the coppiced areas before and after the cutting, indicating a stress in the latter. This pattern is supported by the H’ diversity and evenness values that changed abruptly between years only in the coppiced area. These changes can be related to the significant reduction in tree plant density before and after cutting, especially for those with a diameter between 7.5 and 23 cm.
Anita Kaliszewicz and Olga Dobczyńska
Sessility or isolated habitat can significantly reduce the number of encounters with potential mating partners and thus favour evolution and maintenance of self-fertilisation. Mobility analysis of phylogenetically related species that differs in reproductive mode and self-fertilisation ability could support the widely accepted but not clearly validated theory of selfing being favoured by sessility. Here, we compare mobility in three species of Hydra (Cnidaria, Hydridae) that differ in reproductive strategy: a simultaneous hermaphrodite able to self-fertilise, a sequential hermaphrodite, and a gonochoric species. The results indicate that mobility expressed as distance traversed by individuals is significantly reduced in Hydra circumcincta, a species that is able to self-fertilise, compared to sequential hermaphroditic Hydra vulgaris and gonochoric Hydra oligactis. Differences in mobility were not correlated to individual body size. It is likely that habitat isolation and limited mobility is associated with the evolution of self-fertilisation in such animals like hydras.
Changting Wang, Genxu Wang, Yong Wang, Hongbiao Zi, Manuel Lerdau and Wei Liu
Climate change is likely to alter the relative abundances of plant functional groups and the interactions between plants and soil microbes that maintain alpine meadow ecosystems. However, little is known about how warming-induced alterations to aboveground biomass (AGB) affect soil nutrients and microbial communities. We investigated plant community characteristics in 2002–2009 and analyzed soil properties and the soil microbial community in 2007–2009 to study the effects of warming in Qinghai Province, China. Sampling involved the use of warmed open top chambers, the monitoring of plant community characteristics, the quantification of total and available amounts of soil nutrients, and the evaluation of microbial community composition using phospholipid fatty acid (PLFA) analysis. Experimental warming initially significantly increased the number of plant functional groups and plant community AGB; however, plant community diversity and species richness decreased. Nevertheless, all these variables stabilized over time. Fungal and bacterial abundance, total nitrogen, available nitrogen and soil organic matter increased with warming, while microbial PLFAs decreased. These findings demonstrated that climate change drivers and their interactions may cause changes in soil nutrients and the abundance and content of soil microbial PLFAs. Elevated temperature has strong effects on aboveground grass biomass. Surface conditions and disturbance affect the soil microbial communities of deep soil layers.
Royi Zidon, Hagar Leschner, Uzi Motro and David Saltz
Reintroduction of herbivores may play a vital role in restoring ecosystem functions. Here we describe the role of the Persian fallow deer (Dama mesopotamica), reintroduced into Israel, as a vector of seed dispersal by endozoochory. Persian fallow deer have a wide diet both from grazing and browsing. From fecal samples, we found that more than 30 species of plants germinated from the deer pellets. Four of the more common species are considered as ruderal. Of the trees, carob (Ceratonia siliqua) seeds were the only intact seeds found in the fecal samples. We found that ingestion by the deer has a positive effect on expediting the germination of carob seeds – a factor of ecological importance in the reintroduction environment, as it contributes to plant genetic diversity by long-range seed dispersal and to community diversity.
Huan-Huan Xu, Xing-Lan Chen, Yuan-Hao Yang, Xi Zhou and Jia-Xin Yang
Paraquat and juglone generate reactive oxygen species (ROS) and are widely used to investigate defense mechanisms against ROS in model animals. We cloned cDNA encoding hsp70 from the rotifer Asplanchna brightwelli. The full-length cDNA was 2134 bp and had an open reading frame of 1929 bp encoding 642 amino acids. The deduced amino acid sequence indicated that the Asphsp70 was a cytoplasmic protein and has the highest similarity 87% with Mus musculus, 86% identity with orthologs of Danio rerio, 84% with Apis mellifera and 81% with Xenopus laevis. Expression of Asphsp70 was analyzed under 1.25, 2.5, 5 and 10 mg/L paraquat and 6.25, 12.5, 25 and 50 μg/L juglone. With paraquat, mRNA expression of Asphsp70 significantly increased immediately after exposure for 1 h (P < 0.05). Expression of Asphsp70 temporarily increased after exposure to 2.5 mg/L for 3 and 6 h, and after 10 mg/L for 3 h (P < 0.05). With exposure to 6.25 μg/L juglone, mRNA for Asphsp70 significantly increased at 1, 3 and 12 h; with 12.5, 25 and 50 μg/L, mRNA expression of Asphsp70 significantly increased immediately for 1 h (P < 0.05). These results indicated that the Asphsp70 gene was important in the response to oxidative stress.
Özge Özden and David J. Hodgson
Woodlice (Isopoda: Oniscidae) are known to play important roles in soil profile development and nutrient cycling in agroecosystems. The aim of the present work was to understand the impact of different management regimes on woodlouse fauna in Mediterranean olive groves. The olive groves were located along the Kyrenia mountain range towards the north-west of Cyprus at two different elevations. We used pitfall trapping to compare the abundance of woodlice in groves that were (a) uncultivated at low altitude; (b) uncultivated at high altitude; (c) tilled at low altitude; (d) tilled and chemically managed at low altitude. A total of 1751 woodlice were collected and a significant effect of management regime on the abundance of woodlouse was observed. The low altitude uncultivated olive groves retained a higher number of individuals than the other three management regimes. Our results suggest that tillage alone did not impact severely on woodlouse abundance, but that tillage combined with pesticide and fertilizer application could lead to significant losses in woodlouse abundance in olive grove agroecosystems, with implications for the sustainability of soil quality and biodiversity.
Lara Redolfi De Zan, Sarah Rossi de Gasperis, Luigi Fiore, Corrado Battisti and Giuseppe Maria Carpaneto
This study explored the hole-nesting bird community for two years, in three beech forest stands of central Italy. Our experimental design involved 12 replicated sampling points in each study area for a total of 36 sampling points. Stand characteristics were measured through selected environmental variables (tree diameter, tree density, volume of dead wood, diversity of dead wood and canopy closure), to develop habitat models for describing the factors affecting the abundance of hole-nesting birds. We performed generalized linear models to determine which environmental variables better explained the presence and abundance of hole-nesting birds in the three study areas. The species that showed the highest values of abundance are the Nuthatch, the Blue Tit and the Great Tit. Within the guild of hole-nesting birds there are differences in the selection of suitable trees for nesting, roosting or foraging. Primary cavity nesters (woodpeckers) are mostly related to the presence of large trees, the volume of dead wood and tree height. The presence and abundance of secondary cavity nesters (tits, nuthatches and treecreepers) seem to be mostly influenced by diversity of dead wood. The diversity of dead wood is an important variable that influences the presence and abundance of hole-nesting birds. Maintenance of both living and standing dead wood in forest ecosystems is recommended to increase the effectiveness of conservation actions affecting the hole-nesting birds.
Marek Kowalczyk, Andrzej Jakubczak, Beata Horecka, Magdalena Gryzińska and Grażyna Jeżewska-Witkowska
Domestication of dogs involved strong artificial selection. After their introduction into the human environment, dogs were exposed to factors that were not encountered in the wild. The skin and hair are barriers separating the organism from the environment, and melanin plays a significant role in their protective function. The study compared a fragment of the sequence of the DCT gene, which is involved in melanin synthesis, between two species: the dog, which is exposed to similar carcinogenic factors as humans, and the raccoon dog, a species related to the dog but less exposed to anthropogenic factors.
A fragment of the DCT gene 443 base pairs in length was obtained. Two genotypes were distinguished within the raccoon dog population, differing in one nucleotide in the intron sequence (145A>G). Between the DNA profile of the dog and the consensus sequence of the raccoon dog, 18 polymorphic sites were found – 15 in the intron sequence and 3 in the exon sequence. One change in the exon (191G>A) caused an amino acid change (2E>K). The loss of two binding sites for factor SOX10 and one for JUN-FOS was noted in the dog sequence.
On the basis of the sequence analysed, non-coding regions were found to be more susceptible to changes. Polymorphism in introns may affect the transcription profile of the DCT gene. The loss of binding sites for factors SOX10 and JUN-FOS in the dog may be an adaptive change to a different environment with respect to the raccoon dog.
Xian-Ling Xiang, Rui-Ming Jiang, Ying-Ying Chen, Ya-Li Ge, Xin-Li Wen and Yi-Long Xi
The bdelloid rotifer is an important component of freshwater zooplankton, exhibiting the features of parthenogenesis and anhydrobiotic capability. Heat shock proteins (Hsps), acting as molecular chaperones, are a highly conserved, ubiquitously expressed family of stress response proteins. In this study, the thermal optimums for heat-shock response and the levels of Hsp70 in Rotaria rotatoria (bdelloid rotifer) under different stress conditions were evaluated using survival assays and western blotting with fluorescent detection. The results showed that: (1) The survivorship in R. rotatoria were 100% throughout the temperature range of 12°C to 40°C, and the population growth rate reached its culmination at 28°C, suggesting the retardation of growth and reproduction at the other temperatures; (2) While stressed under 40°C, the levels of Hsp70 in R. rotatoria increased significantly over time, correlating with the duration of the stress; (3) As responses to different temperatures, the synthesis of Hsp70 could be induced significantly in R. rotatoria under both of high (40°C) and low (16°C) temperatures; (4) After removal of the thermal stress and recovery at 28°C, the levels of Hsp70 continued to rise for a period of time, peaked at 12 h, and then slowly declined with the extension of recovery duration, until there is no significant difference of Hsp70 levels. Summarily, with the fluctuations of stress duration and temperature, the rotifers could adapt to the environments sensitively by regulating the synthesis of Hsp70.
Naizheng Xu and Xiao Bai
Urban areas are characterized by diverse land-use patterns and are strongly influenced by anthropogenic activities. However, few studies have examined the effects of urbanization on concentrations of soil organic carbon (SOC) and its various components or δ 13C in urban soils. The aim of this study was to assess the spatial distribution of SOC fractions and δ 13C signatures of urban soils in Shanghai, China. The results showed that SOC fractions and δ 13C compositions differ over a range of spatial scales. The concentrations of SOC, readily oxidizable organic carbon (C), black carbon (BC) and δ 13C in surface soils (0–20 cm) were 10.5, 3.5, 6.9 g kg–1 and –24.9%, respectively, and the corresponding concentrations in deep soils (20–100 cm) were 8.4, 2.8, 6.0 g kg–1 and –23.9%. In urban soils, BC accounted for a higher proportion of the SOC pools. Concentrations of SOC, readily oxidizable organic C and BC were higher, whereas the 13C ratio was much lower in the city centre. The effects of carbon isotope fractionation were also more evident in the central urban area. The results also indicated that not only the concentrations of readily oxidizable organic C and BC but also the δ 13C values were related to the time since the soils were converted to urban use. Differences in the time since urbanization and the severity of the associated environmental impacts can be assessed using SOC fractions and δ 13C isotopic compositions because observed changes in these quantities can be attributed to the strong influence of anthropogenic activities.
Douglas W. Morris
Most organisms live in heterogeneous environments. Yet we know little about how variations in scales of heterogeneity influence decisions on patch use and habitat selection, and how they impact spatial distribution and evolution. In particular, we need to know whether the choice of habitats and patches emerges from a hierarchy of decisions, whether resource consumption correlates closely with space use, and whether different types of individuals are associated with patterns of spatial distribution. I address these knowledge gaps with field experiments that manipulated the risk and quality of foraging patches exploited by male meadow voles. I used clear versus wooden covers to create risky versus safe foraging sites and added supplemental food to create rich versus poor habitats. I assessed whether the resources harvested from each tray matched its frequency of use by groups of voles expressing different temperament scores. Habitat and patch use did not fit a simple hierarchy of decisions because animals merged space use and foraging speed in a sophisticated strategy of risk management. Giving-up densities mirrored activity densities at the scale of safe versus risky patches but not at the scale of safe versus risky or rich versus poor habitats. Voles tended to prefer one habitat over another for reasons independent of the experimental manipulations. Groups of voles with different temperament scores were not linked to foraging types but were linked to habitat preference. The bias in habitat use by different behavioural types provides a potential mechanism for the evolutionary divergence of populations occupying different habitats.
Drug lord Pablo Escobar imported 4 Hippopotamuses (Hippopotamus amphibius) onto his private estate in Colombia in the 1980s. Since his arrest and assassination, the hippos have escaped the confines of the property and have begun to reproduce in the wild of Colombia. They now number approximately 60 individuals. The presence of such a large, and possibly dangerous, species in a new habitat raises several moral and ecological questions and dilemmas. It is unknown what effect these animals may have on their new environment, or the threat that they pose to the people living near them. In an effort to mitigate possible risks to the environment and local populations the Colombian government initiated an effort to castrate all males in the herd. However, it is unlikely that these efforts will be very effective in curbing the population growth of the animals. South America lost most of its large species of animals during the Quaternary Extinction and it is possible that the hippos are filling a gap that still exists in the ecology of the continent. The rewilding efforts occurring around the world aim to restore and protect natural processes and habitats by introducing (or reintroducing) apex predators or keystone species. Perhaps further research could shed light on possible positive influences that the Hippos have on the South American environment and responsible ways to avoid risks to local populations.
Leon Blaustein, Ori Segev, Valentina Rovelli, Shirli Bar-David, Lior Blank, Antonina Polevikov, Nadav Pezaro, Tamar Krugman, Simona Showstack, Avi Koplovich, Lital Ozeri and Alan R. Templeton
The Near Eastern fire salamander, Salamandra infraimmaculata, is considered an endangered species in Israel and is near-threatened regionally. For 25 years, our laboratory has sought ethical sampling methods to protect individuals and populations of Salamandra. To “mark” individuals for estimating dispersal and population size, we use non-invasive individual-specific markings from photographs of larvae and adults. We demonstrated through mesocosm experiments (which are less mortality-driven than in nature) that exotic Gambusia affinis have extreme negative mortality effects on Salamandra larvae. From a compassionate conservation aspect, G. affinis should not be killed and placed in habitats where amphibians are not in danger and mosquitoes can be controlled. We identified breeding-site characteristics demonstrating that permanent breeding sites support larger adult populations than temporary breeding sites. For population genetics studies, we take minimal sized tail tips from adults (which have no adverse effects) for microsatellite data. For gene expression studies, rather than sacrifice entire bodies, we demonstrated that by taking only small larval tail tips, we could follow gene expression. We additionally demonstrated that tail tip removal does not affect survival, time to or size at metamorphosis. We documented high road kill rates at a specific breeding site. To prevent potential disease spread, we sterilize boots and sampling gear. We use results for implementing or recommending conservation of individuals and populations – e.g., identifying: movement corridors for breeding site dispersal; roadkill hotspots for under-road tunnels; suitable habitat for pool construction for more effective conservation; utilizing population genetics for recommending management units; information on demography and genetic diversity to identify hotspots for conservation; removal of Gambusia for amphibian protection.
Dror Ben-Ami and Ray Mjadwesch
Compassionate conservation is an emerging field in conservation that seeks to integrate animal protection and conservation to achieve either improved conservation outcomes, particularly where conservation priorities and human-wildlife conflict, or the same outcomes, but with less pain and suffering for wildlife. In the Australian Capital Territory (ACT), Eastern Grey Kangaroos (EGKs) are culled to reduce grazing pressure on threatened native grasslands and woodlands. We integrate decision-making criteria about animal protection into planning of wildlife-management to formulate a compassionate conservation management case study. The management criteria include a series of guiding questions: Is management necessary? Will intervention (management of EGKs) achieve the desired conservation outcomes? And, if intervention is necessary, is killing necessary? We found that kangaroos can be managed without culling. The conflict between conservation goals and kangaroo abundance is likely to be accentuated during extended drought. In the short-term, methods for improving rates of habitat recovery can include fencing of threatened grassland communities and reduction of kangaroo density via translocation. Human activity must also be monitored as multiple human-caused biotic and abiotic disturbances are known to have a strong impact on biodiversity of the native grassland habitats. In the medium to long-term, Eastern Grey Kangaroos have the potential for maintaining stable populations, and their herbivory is necessary for grassland function and nutrient cycling. Finally, we suggest that compassionate conservation and adaptive management can work well together as social values shift towards greater emphasis on animal protection.
Shira Yashphe and S. Lisa Kubotera
Coyotes (Canis latrans) are native to North America and are frequently seen in and around urbanized areas. As human population grows and urban sprawl encroaches on coyote habitat, human-coyote conflicts increase. Faced with the need to find solutions, policy-makers, and conservationists are challenged with the task of designing coyote management programs that would ensure public safety while conserving the species. The need to consider the welfare of individual animals, as encompassed by the emerging field of Compassionate Conservation, adds an additional challenge. By examining two coyote management programs’ case studies in North America—one in Long Beach, California and another in Oakville, Ontario—the benefits of adopting compassionate solutions are illustrated. As exemplified by Oakville’s strategy, compassionate programs promote the moral treatment of animals while proving to be economically and socially superior to strategies employing lethal measures. Such strategies adopt proactive, rather than reactive responses to human-coyote encounters and invest heavily in public engagement and education. Through the development, implementation, and regulation of non-lethal wildlife management policies, more cities and towns will be able to meet the needs of the stakeholders involved in coyote-human conflict while sparing the life of the animal.
Arian D. Wallach, Erick Lundgren, Esty Yanco and Daniel Ramp
Human-assisted biotic migration is a hallmark of the Anthropocene. Populations introduced outside their native ranges (‘migrant species’) have commonly been viewed as a threat to be addressed with lethal control programs. Israel has a long history of anthropogenic changes, and conservation has typically focused on ameliorating direct human impacts rather than eradicating migrant species. However, this may be changing with the growing influence of invasion biology worldwide. We conducted a review of the diversity, conservation status, and academic attitudes toward Israel’s migrant species (IMS). We identified 199 plants and animals from 85 families that have immigrated into Israel from across the globe, and 122 species from 64 families considered native to Israel that have emigrated to every bioregion and to two oceans, although few species have become cosmopolitan. The conservation status of most immigrant (84.9%) and emigrant (55.7%) species has not been assessed, and even the native ranges of eleven immigrants (5.5%) remains unknown. Of those assessed, 27% of immigrants are threatened or decreasing in their native ranges, and 62% of emigrants are globally decreasing or locally threatened and extinct. After accounting for local extinctions, immigration has increased Israel’s plant and vertebrate richness by 104 species. Israel’s immigrants are increasingly being viewed from an invasion biology perspective, with 76% of studies published in the past decade, reaching over a quarter of local conservation publications. Incorporating principles of compassionate conservation could help foster a more socially acceptable and morally grounded approach to the immigrant wildlife of the Middle East.
Compassionate Conservation seeks to merge the protection of animals and nature for improved conservation outcomes. Although Compassionate Conservation has broad disciplinary scope, its emergence at the interface of animal welfare science and conservation biology remains formative. Translocation biology offers an important opportunity to showcase the compassionate conservation approach because translocations encompass direct care and management of individual animals along with concerns for population and species health. Historically, a one-size-fits-all approach to translocations has proven to be misguided. Current advances in the field offer an important opportunity to apply the methodological focus that animal welfare science has on individuals and social groups for improved conservation outcomes. In particular, the evolutionary and behavioural science insights into the personality of individual animals highlights that the welfare of individual animals and the variation among them are integral to population and species recovery. In a review of translocation biology, animal personality and with the inclusion of a translocation case study, I show that translocation biology offers a clear case for the application of Compassionate Conservation principles.
Arnon Lotem, Stephen I. Rothstein and Yoram Yom-Tov
Yehudah L. Werner
Opinions differ whether tail loss in lizards is mainly caused by predators or by intra-specific fighting. Recently this dilemma was investigated through a comparison of lizard tail loss rates between mainland populations in Greece and those on nearby islands harboring fewer predators. The higher tail loss rate on the islands was interpreted as due to the predation-free denser lizard populations having more intra-specific fighting (Itescu et al. 2017, Journal of Animal Ecology 86: 66–74). However, that analysis failed to exclude an alternative hypothesis which I propose and support with well documented circumstantial evidence: The lizards analyzed were Hemidactylus turcicus and Mediodactylus kotschyi (Gekkonidae), both relatively long-lived. On the predator-poor islands they could live longer due to the few predators and thus accumulate the low rate of tail loss. Moreover, both on the mainland and on the islands the tail loss rates are higher in M. kotschyi than in H. turcicus, although life spans are of similar order of magnitude, possibly longer in H. turcicus. But the latter is active at night whereas M. kotschyi is active also in daytime, exposed to more predators during more time. Thus also this inter-specific difference accords with the alternative hypothesis. The two processes are not mutually exclusive and both should be taken into account as potentially responsible for the rate of tail loss in lizards.
Izabella Olejniczak and Stanisław Lenart
In 2009 and 2010, we examined the effects of different tillage systems on springtail communities. The study was established on the experimental field, in which tillage and no-tillage cultivation had been conducted since 1975, of the Research Station of the Warsaw University of Life Sciences’ Department of Agronomy, located at Chylice, near Warsaw (52005’N, 20033’E).
The treatments considered were conventional tillage with a mouldboard plough (CT) and no-tillage (NT), and each method was divided between with and without liming. In 2009, the fields were sown with winter wheat, and spring barley was planted the following year. During both growing seasons, collembolan densities were higher under NT than CT, but the reverse was true after harvest. However, the time of the season had a significant effect on collembolan densities not only over the whole study period but also in particular years. Additionally, in fields that were limed, collembolan densities varied, with no clear trend. The dominant collembolan species in the CT and NT fields was Isotoma viridis Bourlet, 1839, while Paristoma notabilis (Schäffer, 1896) was prevalent when liming was used. The relative proportion of each of the two species in springtail communities was at least 20 percent. The species diversity of collembolan communities was similar in both study years, and it was higher in CT than in NT fields.
The study was financially supported as part of the MNiSW project No. N N305171136.
Corrado Battisti, Marco Giardini, Francesca Marini, Lorena Di Rocco, Giuseppe Dodaro and Leonardo Vignoli
We reported a study on breeding birds occurring inside an 80 m-deep karst sinkhole, with the characterization of the assemblages recorded along its semi-vertical slopes from the upper edge until the bottom. The internal sides of the sinkhole have been vertically subdivided in four belts about 20 m high. The highest belt (at the upper edge of the cenote) showed the highest values in mean number of bird detections, mean and normalized species richness, and Shannon diversity index. The averaged values of number of detections and species richness significantly differ among belts. Species turnover (Cody’s β-diversity) was maximum between the highest belts. Whittaker plots showed a marked difference among assemblages shaping from broken-stick model to geometric series, and explicited a spatial progressive stress with a disruption in evenness towards the deepest belts. Bird assemblages evidenced a nested subset structure with deeper belts containing successive subsets of the species occurring in the upper belts. We hypothesize that, at least during the daytime in breeding season, the observed non-random distribution of species along the vertical stratification is likely due to (i) the progressive simplification both of the floristic composition and vegetation structure, and (ii) the paucity of sunlight as resources from the upper edge to the inner side of the cenote.
Hugh Lefcort and Burt P. Kotler
Abstract In addition to effects on climate and water acidification, anthropogenic atmospheric releases of carbon dioxide may also directly impact terrestrial organisms that use CO2 as a chemical cue. We wondered how common organisms would respond to near-future levels of CO2 – levels that may occur by 2025. We chose two common but taxonomically and ecologically dissimilar organisms (Theba pisana helicid snails and Adesmia dilatata tenebrionid beetles) to examine the behavioral effects of a slight rise (~10 ppm) of CO2 on animal abundance and plant growth in the Negev Desert of Israel. We found that plots with supplementary CO2 exhibited greater plant growth than control plots over a 50-day experiment, but increased growth did not alter beetle or snail numbers.
In laboratory experiments with higher levels of augmented CO2 paired with food rewards, we found that snails did not change their climbing behavior when presented with CO2 alone, but they avoided food and climbed away when CO2 was paired with food. Beetles in the laboratory were attracted to food regardless of CO2 levels although high levels of CO2 (1200–1300 ppm) reduced movement.
The direct effects of near-future CO2 levels may augment plant growth but have only minor influence on terrestrial snails and beetles. However, the effects of CO2 on climate change in desert habitats like the Negev may be more severe due to a predicted rise in temperature and a decline in precipitation.
Yuval Itescu, Rachel Schwarz, Shai Meiri and Panayiotis Pafilis
We recently studied whether, on islands, predation or intraspecific aggression is the main driver of tail-loss, a common defense mechanism among lizards. We concluded the latter was the stronger driver (Itescu et al. 2017). Werner (2017) suggested that we failed to falsify an alternative hypothesis. He claims that on low-predation islands lizards live longer. Thus while tail loss is caused by predators, it accumulates over longer periods, resulting in overall higher tail-loss rates in populations experiencing weak predation. Here we test this hypothesis and three other arguments he presented, and fail to support them. We therefore adhere to our original conclusion that intraspecific aggression is the main driver of lizard tail loss on islands.
Myriam Freund, Ofer Bahat and Uzi Motro
We studied the use of nest-sites by Griffon Vultures (Gyps fulvus) and the breeding success in these sites during 1998–2002 in Gamla Nature Reserve (Israel). Nest-sites in which a breeding attempt succeeded in fledging a young, were more likely to be occupied by nesting vultures in the following breeding season, than nest-sites that experienced a failure. This suggests that Griffon Vultures in Gamla used a Win–Stay/Lose–Shift strategy regarding nest-site fidelity.
Mao Wang, Pengcheng Wan, Jiangchao Guo, Jinshi Xu, Yongfu Chai and Ming Yue
Leaves, stems and roots as the main plant organs have specific functions and together modulate survival, growth and reproduction. The relationships between these organs are high research priority, and there have been many hypotheses about the trade-offs between them. However, the results of these hypotheses are inconsistent and confusing. In this study, we examined 15 core traits of leaves, stems and woody roots of 27 dominant shrub species and further tested the hypotheses about the relationships between these organs. Measurements were made for shrubs across 9 sites including desert, steppe, temperate forest and subtropical forest in Shaanxi Province of China. Many significant correlations of different organ traits were found, e.g. nitrogen and phosphorus content showed a significant positive correlation, either within or across organs. Also, representatives of structural traits (carbon content and dry matter content) and mineral nutrient traits (nitrogen and phosphorus content) showed significant positive correlations among the leaves, stems and roots. The results of this study supported the hypotheses that there were significant correlations between leaf and root and between stem and root. Similarly, we found that trade-off between leaf and stem-plus-root showed a significant correlation. Thus, root traits, which are difficult to measure, are coordinated with those of the leaf and stem. We conclude that the leaf component of shrubs is a good proxy for the whole-plant in studying trade-offs and it could provide a convenient way to understand the whole-plant economic spectrum by focusing on the leaf economic spectrum.
The present review is in part a complement to the prompt, knowledgeable and favorable review by Anderson (2016) that, however, failed to reflect certain unique aspects of the book.
Muhsin Çoğal and Mustafa Sözen
Gazella gazella was discovered recently in a restricted area in the Hatay province, Southern Turkey, which constitutes the northern most point of the distribution of this species in the world. To determine the distribution of the population of mountain gazelles in the Hatay region, 17 camera-traps were set along 45 km, on a line from the south to north along the Syrian border. The traps were in the field for about five months from late May to mid-October in 2016. Field observations and conversations with local people, wildlife officers and researchers were performed to gain more information about the habits and distribution of the gazelles. Two isolated sub-populations were found: The northern one in the Kırıkhan region; about 520 gazelles in an area of about 100 km2, and separated by 18 km to the south, and some 20 gazelles in an area of about 25 km2 in the Reyhanlı region. This southern sub-population was first discovered in this research. Fourteen species of mammals were recorded with photo-traps. Hemiechinus auritus is a new record for the Hatay region. The conservation efforts after the discovery of the northern mountain gazelle sub-population, assisted an increasing trend in its size, and resulted in finding the additional sub-population in the Reyhanlı region.
Merav Wacht Katz, Zvika Abramsky, Burt P. Kotler, Michael L Rosenzweig, Ofir Altstein, Inbar Roth and Constantine Klimovitsky
Little egrets (Egretta garzetta) and common goldfish (Carassius auratus) interacted in experimental theaters that challenge them with a behavioral game. We studied the behavioral tactics of both players. The experimental theaters consist of three equally spaced pools, each with a shelter in its center. The fish can take shelter in a safe but foodless habitat, or swim exposed in the open that contains food. The egrets can move among the pools to catch the exposed fish. We investigated the importance of non-lethal effects versus lethal effects on predator–prey interactions. We created a variance in predation pressure by keeping the number of egrets fixed but varying the number of pools of the experimental theater between 1 and 3 pools. In all treatments, even when the egret was present, individual goldfish emerged from protected cover occasionally, exposing at least their heads and sometimes their entire bodies in apparent disregard for the possibly lethal consequences. We assumed that this behavior stems from the fish's constant need to collect information about its surroundings. The fish responded appropriately to the variations in predation pressure by changing their activity level outside the cover, i.e., the fish drastically and significantly reduced their exposure outside the cover, as well as the rate of peeping, as predation pressure increased. The results demonstrate the importance role of non-lethal effects, and how they drive the behavior of prey in response to predation risk, which in turn, drives the action of the predator in an asymmetric two-player game of stealth and fear.
Christine Thuring and Gary Grant
Ido Tsurim and Alon Silberbush
Larvae of the mosquito Culiseta longiareolata Macquart have been suggested as important species in desert and Mediterranean temporary pond ecosystems through their strong competitive abilities and as intra-guild predators. We examined their potential predatory effect on larvae of the abundant saltmarsh mosquito Ochlerotatus caspius. We did not find evidence for predatory effects of C. longiareolata on O. caspius larvae. We suggest that, at least in our system, C. longiareolata is an apparent predator. Namely, it does not actively prey on mobile victims, but rather feeds on the carcasses of its fallen competitors additional to its generally immobile food. Hence, we do not expect the occurrence of anti-predator behaviors in response to C. longiareolata presence, including larval development characteristics and oviposition habitat selection.
Editors Israel Journal of Ecology & Evolution
Elsita M. Kiekebusch and Burt P. Kotler
The study of herbivore patch use has implications for herbivore habitat quality assessment, foraging behaviors, species interactions, and coexistence in patchy environments. This research focuses on the comparison of the effects of two qualitatively different plant defenses, mechanical (thorns) and chemical (tannins), on ibex foraging preferences during different seasons of the year. The occurrence of both chemical and mechanical plant defenses were experimentally manipulated in artificial resource patches, in addition to water availability. Ibex foraging preferences were quantified using giving-up densities during four separate fieldwork sessions in each of the seasons of the year at cliff sites overlooking the Zin Valley of the Negev Highlands. Both mechanical and chemical plant defenses significantly hindered ibex food intake overall. Mechanical and chemical defenses acted as substitutable defenses, meaning that their combined effects were not greater than additive. There were strong seasonal patterns of the amount of food consumed by ibex, further corroborated by comparison to rainfall levels. Seasonality also interacted with the effectiveness of plant defenses. Thorns were especially ineffective in summer, whereas tannins were most effective in spring. Decreases in seasonal food availability and increased marginal value of energy for ibex may have resulted in thorn ineffectiveness, while seasonal changes in the emergence of young foliage may have resulted in the greater springtime tannin effectiveness. Water was not found to mitigate the detrimental effects of tannins through dilution. The implications for decreased constraints on selective pressures on ibex due to the substitutability of plant defenses are discussed.
Ling-Ying Shuai, Yan-Ling Song, Burt P. Kotler, Keren Embar and Zhi-Gao Zeng
We studied the foraging behaviour of two sympatric rodents (Meriones meridianus and Dipus sagitta) in the Gobi Desert, Northwestern China. The role of the foraging behaviour in promoting species coexistence was also examined. We used giving-up densities (GUDs) in artificial food patches to measure the patch use of rodents and video trapping to directly record the foraging behaviour, vigilance, and interspecific interactions. Three potential mechanisms of coexistence were evaluated (1) microhabitat partitioning; (2) spatial heterogeneity of resource abundance with a tradeoff in foraging efficiency vs. locomotion; and (3) temporal partitioning on a daily scale. Compared to M. meridianus, D. sagitta generally possessed lower GUDs, spent more time on patches, and conducted more visits per tray per capita, regardless of microhabitat. However, M. meridianus possessed advantages in average harvesting rates and direct interference against D. sagitta. Our results only partly support the third mechanism listed above. We propose another potential mechanism of coexistence: a tradeoff between interference competition and safety, with M. meridianus better at interference competition and D. sagitta better at avoiding predation risk. This mechanism is uncommon in previously studied desert rodent systems.
Allison E. Bannister and Douglas W. Morris
We use theories of risk allocation to inform trade-offs between foraging in a rich and risky habitat versus using a poor but safe alternative. Recent advances in the theory predict that the length of exposure to good or bad conditions governs risk allocation, and thus habitat choice, when patterns of environmental risk are autocorrelated in time. We investigate the effects of these factors with controlled experiments on a small soil arthropod (Folsomia candida). We subjected animals to nine temporally autocorrelated 16-day feeding treatments varying in both the proportion (0.25, 0.50, and 0.75) and duration (short, medium and long intervals) of time when food was present and absent. We assessed foraging trade-offs by the animals' choice of occupying a risky dry habitat with food (rich) versus a safe moist habitat with no food (poor). Irrespective of autocorrelation in conditions, the proportion of time spent with no food primarily determined habitat selection by these collembolans. Our results imply an energetic threshold below which F. candida are forced to forage in rich and risky habitat despite the possibility of mortality through desiccation. The link to energetic thresholds suggests the possibility of employing state-dependent habitat selection as a leading indicator of habitat change.
Burt P. Kotler, Joel S. Brown, Sonny S. Bleicher and Keren Embar
Desert rodent assemblages from around the world provide convergent, but independent crucibles for testing theory and deducing general ecological principles. The heteromyid rodents of North America and the gerbils of the Middle East and their predators provide such an example. Both sets of rodents face predation from owls and vipers, but the North American species possess unique traits that may represent macroevolutionary breakthroughs: rattlesnakes have infra-red sensitive sensory pits, and heteromyids have cheek pouches. To test their significance, we brought together two gerbils (Middle East), two heteromyid rodents (a kangaroo rat and a pocket mouse; North America) in a common setting (a vivarium in the Negev Desert), and quantified the “opinions” of the rodents towards the North American sidewinder rattlesnake and the Middle Eastern Saharan horned viper and the foraging behavior of each in the face of these snake predators plus owl predators. Gerbils are fairly evenly matched in their anti-predator abilities, while the heteromyids differ widely, and these seem to match well with and may determine the types of mechanisms of species coexistence that operate in the communities of each continent. Evolutionary history, macroevolutionary traits, and risk management therefore combine to determine the characteristics of the organisms and the organization of their communities.
Robert D. Holt
Sonny S. Bleicher, Joel S. Brown, Keren Embar and Burt P. Kotler
Unlike desert rodents from North America, Allenby's gerbil (Gerbillus andersoni allenbyi) from the Negev Desert, Israel has evolved with snakes that do not have heat-sensitive sensory pits that enhance night vision. Does this history affect their ability to assess and respond to a snake that has this ability? As a test, we exposed gerbils to risk of predation from various predators, including snakes, owls, and foxes. The snakes included the Saharan horned viper (Cerastes cerastes) and the sidewinder rattlesnake (Crotalus cerastes). The former snake lacks sensory pits and shares a common evolutionary history with the gerbil. The latter snake, while convergent evolutionarily on the horned viper, has sensory pits and no prior history with the gerbil. The gerbils exploited depletable resource patches similarly, regardless of snake species and moon phase. While the gerbils did not respond to the novel snake as a greater threat than their familiar horned viper, the gerbils were cognizant that the novel predator was a threat. In response to both snakes, giving-up densities (GUDs; the amount of food left in a resource patch following exploitation) of the gerbils were higher in the bush than open microhabitat. In response to moonlight, GUDs were higher on full than on the new moon. Based on GUDs, the gerbils responded most to the risk of predation from the red fox, least from the two snake species, and intermediate for the barn owl.
Deborah Saward-Arav, Asaf Sadeh, Marc Mangel, Alan R. Templeton and Leon Blaustein
Natural selection is predicted to favor females that can detect risks of desiccation and predation when choosing among temporary pools for oviposition. Pool size may serve both as a cue for desiccation risk and as a predictor for future colonization by predators or for the probability of present, undetected predators. Therefore, oviposition responses to pool size are expected to interact with the presence of predators that can be detected. We measured oviposition by two mosquito species, Culiseta longiareolata and Culex laticinctus, in a mesocosm experiment, crossing two pool surface sizes with presence or absence of the hemipteran predator, Notonecta maculata, which is chemically detectable by mosquitoes. Both mosquito species strongly avoided Notonecta pools. Using a mechanistic statistical model, we accounted for the higher encounter rate of females with larger pools, and determined their true oviposition preferences for pool size. C. laticinctus showed a clear preference for larger pools, but C. longiareolata, a species with larvae more vulnerable to predation, showed no significant preference for pool size. This study confirms the importance of risk of predation in explaining oviposition patterns, and suggests a possible inter-specific variation in the trade-off between predation and desiccation risks.
Joel S. Brown, Keren Embar, Eric Hancock and Burt P. Kotler
Derring-do is how aggressive a predator is in stalking and capturing prey. We model predator–prey interactions in which prey adjust vigilance behavior to mitigate risk of predation and predators their derring-do to manage risk of injury from capturing prey. High derring-do increases a predator's likelihood of capturing prey, but at higher risk of injury to itself. For fixed predator derring-do, prey increase vigilance in response to predator abundance, predator lethality, and predator encounter probability with prey and decrease vigilance with their own feeding rate; there is a humped-shaped relationship between prey vigilance and effectiveness of vigilance. For fixed prey vigilance, predators increase derring-do with the abundance of prey and predator lethality and decrease it with benefit of vigilance to prey and level of prey vigilance. When both prey and predator are behaviorally flexible, a predator–prey foraging game ensues whose solution represents an evolutionarily stable strategy (ESS). At the ESS, prey provide themselves with a public good as their vigilance causes predators to decrease derring-do. Conversely, predators have negative indirect effects on themselves as their derring-do causes prey to be more vigilant. These behavioral feedbacks create negative intra-specific interaction coefficients. Increasing the population size of prey (or predators) now has a direct negative effect on the prey (or predators). Both effects help stabilize predator–prey dynamics. Besides highlighting a common way by which predators may experience a food-safety tradeoff via dangerous prey, the model suggests why natural selection favors even small defensive measures by prey and hulky predators.
Hannu Ylӧnen and Marko Haapakoski
Mating with close kin may cause inbreeding depression with negative consequences to offspring and local populations. There exist mechanisms like kin-recognition or sex-specific dispersal to avoid mating with kin. In fluctuating population densities, like in many small mammals, both very low and very high densities provide conditions for inbreeding, if kin males are prone to stay in their natal area. Females are choosy and male dominance is thought to be the key feature when selecting mating partners. The aim of this study was to test the possible discrepancy in mate choice and negative fitness effects of inbreeding in two experiments, one in the laboratory and one in field enclosures. We asked (1) how the quality of the potential mating partners affects female choice regardless of relatedness and (2) how inbreeding affects the field populations created either from inbred or outbred individuals. Our results show that primiparous females in post-partum oestrus mated preferably with a dominant male, measured with their urine-marking behaviour, regardless if the selected male was brother or not. Only if the two males offered were of same dominance rank, the female mated with the non-kin male. However, the field experiment verified a negative effect of inbreeding in the bank vole. Thus, there seems to be a mismatch between female mate choice when selecting for dominance among resident males and population viability through long-term inbreeding depression. The study suggests the high importance of sex-biased dispersal as a mechanism to avoid kin individuals to meet in mate choice situations.
Predators affect prey directly by predation and indirectly by triggering behavioral responses that aim at reducing predation risk. In this paper, I present a method for training an avian predator which can allow separating between its direct and indirect effects on prey in various experimental setups. Barn owls are found to be a valuable tool for empirically testing different hypotheses related to predator-prey interactions, population dynamics, and inter-specific competition, all performed in the field using authentic rodent prey and their natural predators. Barn owls are raised and trained to participate in field experiments using classical conditioning, and are trained either to catch rodents or only to fly above a certain area without making any attempt to attack the prey, simulating solely predation risk. Body mass is a crucial factor in the training procedure, and I thus define five body mass ranges that characterize different behavioral stages in the training of owls. A logistic model is used to calculate and to predict changes in the body mass during the growth and training periods of owls. Finally, I discuss several possible implications of the usage of trained barn owls in empirical studies.
Christine Thuring and Gary Grant
From its beginnings in Germany in the twentieth century, a thriving extensive green roof industry has become established in many countries in temperate climates. Based upon the success of the industry, and with an expectation that this technology will be adopted in other climates, this review of the ecological research of extensive green roofs aims to evaluate the application of this knowledge. The modern extensive green roof is the product of research in the 1970s by German green roof pioneers; the selection of suitable species from analogue habitats led to green roof vegetation dominated by drought tolerant taxa. The commercial success of extensive green roof systems can be attributed to engineering and horticultural research, to policy mechanisms in some places, and to a market that encourages innovation, and the origins in ecological design are now easily overlooked. Some of the work reviewed here, including the classification of spontaneous roof vegetation into plant communities, is not widely known due to its confinement to the German literature. By re-visiting the history of the extensive green roof and reviewing the ecological research that has contributed to our understanding of it, the intention is, for this paper, to inform those considering green roofs in other climatic regions, to apply an ecologically informed approach in using local knowledge for developing installations that are suited to the bioregion in which they occur. Finally the paper considers some future directions for research and practice.
Nicole L. Kinlocka, Bracha Y. Schindler and Jessica Gurevitch
Green roofs can mitigate a number of urban environmental problems when green roof plant communities provide ecosystem services. However, this perspective may fail to address ecological aspects of the plant community. In particular, it does not account for the potential for green roofs to facilitate biological invasions. We consider current research in green roof ecology in light of the literature on biological invasions, focusing on plant invasion. We evaluate the role of species composition and novel communities, species interactions, succession, and dispersal on the trajectory of green roof plant communities. Green roofs have the potential to introduce invasive species through initial plantings, to become dominated by invasive species, and to spread invasive species, and we provide recommendations for plant selection and maintenance to reduce the risks of facilitating plant invasions to surrounding communities.
J. Scott Maclvor
Vegetated, “green” infrastructure, including terraces, balconies, and vegetated roofs and walls are increasingly common in urban landscapes, elevating habitat into novel contexts above ground. Highly mobile species, like bees and wasps, are often seen foraging on green infrastructure, but whether nesting opportunities are facilitated is not known. Cavity-nesting bees and wasps that provision brood in human-made trap nests were monitored over three years on 29 vegetated and non-vegetated roofs in Toronto, Canada. The study identified 27 species nesting on rooftops but found that building height was negatively correlated with the abundance of brood cells provisioned in trap nests, and positively correlated with the number of unfinished nests. A decline in green space area within a 600 m radius around each rooftop resulted in decreasing species richness and abundance. Although the introduced bee, Megachile rotundata (Fabricius) occupied more sites than any other bee or wasp (27.6%) and was the most abundant species, amounting to half (48.9%) of all brood reared, native bees were 73% of all bee species reared. The most abundant wasp was the native spider-collecting Trypoxylon collinum Smith (11.4%), but the introduced aphid-collecting Psenulus pallipes (Panzer) occurred at more sites (24.1%). For the pollination and pest controlling services they provide, bees and wasps should be considered in the design of vegetated roofs. Evidence here suggests that building height and surrounding green space at ground level impact bee and wasp diversity on vegetated roofs. Efforts supporting their populations using trap nests should target low- and mid-rise buildings (<5 building levels).
This paper explores the application of an ecosystem ecology framework to greenroof systems. It investigates how aspects of greenroof design or structure relate to functions such as rates of nutrient and energy cycling. Three main sections include energy budgets, cycling of nutrients and water, and ecosystem response to disturbance. Comparisons between greenroofs and other systems indicated that, functionally, greenroofs may be very different from ecosystem analogs. A further assessment of the greenroof energy budget called into question how food webs are supported. An evaluation of factors predicting system response to disturbance identified ways in which greenroofs may be less resilient to disturbance. One challenge with the ecosystem approach is a lack of sufficient data for fully holistic models, especially with respect to management practices. Ecosystem ecology is nevertheless shown to be a valuable framework for integrating existing greenroof research as well as targeting areas for future research and model development.
Robert D. Holt
A “green roof” is a roof on a structure created by humans, which has a plant community (and various hangers-on) established on it. There are many potential benefits of green roofs, ranging from moderation of local microclimates to modulations of storm runoffs, and green roofs may serve the enhancement of biodiversity conservation, as well. Green roofs would seem to be quintessential examples of a “novel ecosystem”. Here, I first outline some dimensions of the novelty that warrant more research. Green roofs can provide many opportunities for creative ecological research in the assembly, dynamics and functioning of novel ecosystems. Then, I briefly discuss some potential biodiversity hazards that are created along with green roofs. Recognizing these potential “shadows” of a green roof by no means belies the strong and compelling rationale for promoting green roofs, in terms of sustainability and livability of human structures; instead the points I raise are simply issues which should be evaluated and quantified when promoting green roofs broadly as a design strategy in new buildings or retrofitted existing structures.
Michael L. Rosenzweig
Many contributions to the symposium seek to expand the role of green roofs in the conservation of biodiversity. Indeed, if green roofs can be harnessed for biodiversity, they will add area to that now available to nature. That would have the mass effect of increasing the sustainable number of species in simple conformity with the species--area relationship. Because all green roofs are novel ecosystems, all represent instances of reconciliation ecology, i.e., re-engineering human uses to permit simultaneous beneficial use by people and nature. Green roofs can provide a large number of experiments that might teach us how to improve their design. But those experiments, like any in science, must be overtly designed so that their hypotheses are clear and explicit, their methods repeatable, and their data appropriate for rigorous analysis. I present an embryonic example using native plant species growing at ground level in the urban environments of Tucson, AZ, USA. Steps include: (1) formulating a hypothesis; (2) developing a database of species' attributes to allow intelligent selection for hypothesis testing; (3) developing software to allow winnowing the list of species to sets with a good chance, according to the hypothesis, of growing together; (4) installing the sets of plants and measuring the results; (5) defining a continuous measure of conformity with the hypothesis; and (6) comparing results to hypothesis. If ecologists can successfully design reconciled ecosystems in urban settings – green roofs included – city people will be able to re-establish their everyday connection to nature.
Inga Dirks, Buzi Raviv, Oren Shelef, Amber Hill, Eppel Amir, Moses Kwame Aidoo, Brian Hoefgen, Tal Rapaport, Hila Gil, Endale Geta, Amnon Kochavi, Itay Cohen and Shimon Rachmilevitch
Green roofs in the Mediterranean region are often exposed to high levels of radiation, extreme temperatures, and an inconsistent water supply. To withstand these harsh conditions in shallow soils and poorly aerated growth media, plants must be armored with adaptations. Strategies that have evolved in desert plants can play significant roles in the use of plants for green covers. In the following, we will specifically focus on (1) heat and radiation, (2) drought, and (3) salinity. Further, we will discuss (4) interactions between neighboring plants. Finally, we will (5) propose a design for diverse green roofs that includes horticultural and medicinal products and provides diverse habitats. Many desert plants have developed morphological and anatomical features to avoid photo-inhibition, which can be advantageous for growth on green roofs. Plants exhibiting C4 photosynthesis or crassulacean acid metabolism (CAM) photosynthesis have a protected hydraulic system that enables growth under dry conditions. Furthermore, dew and high levels of relative humidity can provide reliable water sources under limited precipitation. Halophytes are protected against salinity, ionic specific stress, and nutritional imbalances, characteristics that can be advantageous for green roofs. Under limited space, competition for resources becomes increasingly relevant. Allelopathy can also induce the germination and growth inhibition of neighboring plants. Many desert plants, as a result of their exposure to environmental stress, have developed unique survival adaptations based on secondary metabolites that can be used as pharmaceuticals. A systematic survey of plant strategies to withstand these extreme conditions provides a basis for increasing the number of green roof candidates.
C. Nash, J. Clough, D. Gedge, R. Lindsay, D. Newport, M.A. Ciupala and S. Connop
Cities dominated by impervious artificial surfaces can experience a multitude of negative environmental impacts. Restoration of green infrastructure has been identified as a mechanism for increasing urban resilience, enabling cities to transition towards sustainable futures in the face of climate-driven change. Building rooftops represent a viable space for integrating new green infrastructure into high-density urban areas. Urban rooftops also provide prime locations for photovoltaic (PV) systems. There is an increasing recognition that these two technologies can be combined to deliver reciprocal benefits in terms of energy efficiency and biodiversity targets. Scarcity of scientific evaluation of the interaction between PVs and green roofs means that the potential benefits are currently poorly understood. This study documents evidence from a biodiversity monitoring study of a substantial biosolar roof installed in the Queen Elizabeth Olympic Park. Vegetation and invertebrate communities were sampled and habitat structure measured in relation to habitat niches on the roof, including PV panels. Ninety-two plant species were recorded on the roof and variation in vegetation structure associated with proximity to PV panels was identified. Almost 50% of target invertebrate species collected were designated of conservation importance. Arthropod distribution varied in relation to habitat niches on the roof. The overall aim of the Main Press Centre building green roof design was to create a mosaic of habitats to enhance biodiversity, and the results of the study suggest that PV panels can contribute to niche diversity on a green roof. Further detailed study is required to fully characterise the effects of PV panel density on biodiversity.
Leon Blaustein, Gyongyver J. Kadas and Jessica Gurevitch
Green roofs can provide environmental benefits that include increased building insulation, mitigating urban heat islands, providing aesthetic value, reducing runoff and storm water flooding in urban environments, improving air quality by sequestering pollutants, cooling photovoltaic panels to improve their function, and providing habitat for fauna and flora. Until very recently, improvements of green-roof environmental services had been achieved largely by horticulturalists, engineers, and architects. In recent years, ecologists have increased their participation, implementing ecological theory for enhancing biodiversity, and selecting specific plant assemblages for other environmental services such as carbon sequestration and for providing cooler roofs. Moreover, ecologists can use green roofs as relatively novel habitats for testing and developing ecological theory. This special issue is devoted to fostering input from ecologists for advancing the environmental and ecosystem services of green roofs. A wide range of ecologists can explore the topic of the ecological aspects of green roof design and implementation including island biogeography theory, niche theory and null models, the role of environmental heterogeneity, invasion ecology, and plant selection. They can contribute ecological methodology and study design for strong inference.
Bracha Y. Schindler, Lior Blank, Shay Levy, Gyongyver Kadas, David Pearlmutter and Leon Blaustein
The integration of photovoltaic (PV) panels and green roofs has the potential to improve panel efficiency to produce electricity and enhance green roof species diversity and productivity. In this review, we provide an overview of research on the effects of green roofs on PV panel electricity production, and predict the expected effects of the PV panel on green roof plant communities. Previous studies suggest that PV panels are more efficient above a green roof than above several types of conventional roofs due to the cooling effect of green roofs on the temperature-sensitive PV cells. Some ecological studies on shade suggest that shade imposed by panels may enhance the biotic productivity of green roofs. Shade is often shown to be important for seedling survival, particularly in arid environments – so the effect of shade on plants may depend on climate and irrigation. Previous studies also suggest that shade variations over the roof area may enhance plant diversity, as such heterogeneity creates niches of light and moisture levels that are appropriate for a diversity of plants. These positive effects on plant diversity may lead to increased arthropod diversity as well. Additional replicated studies are needed to test the reciprocal effects of green roofs and PV, as past studies lacked replication. Future directions for research that could guide the design of green roof–PV integration include the effects of irrigation, plant diversity, and green area-to-panel ratio on the roof.
Amiel Vasl and Amy Heim
The growing phenomenon of green roofs throughout the world mostly results in the establishment of extensive green roofs with low species diversity. However, research from the last few decades has shown that several advantages can accrue from diverse ecological systems, such as increased faunal diversity, storm water retention, thermal stability, pollution mitigation, and visual appeal. The maintenance of diversity on extensive green roofs has not been closely examined and few studies incorporate methods to ensure long-term coexistence into green roof design. Theoretical work has placed much focus on the niche and neutral theories that attempt to explain diversity as a result of the existence of different habitats or of demographic and dispersal patterns, respectively. These theories have resulted in several theoretical and practical recommendations for the maintenance of diversity in ecological systems and could suggest additional practices that would support biodiverse green roofs. We hereby review and discuss relevant theory and supporting research to provide suggestions regarding future research in the field as well as practical green roof construction recommendations and species selection.
Jeremy T. Lundholm
Green roofs and other constructed environments represent novel ecosystems, yet have potential to contribute to biodiversity conservation goals. Constructed ecosystems are intentionally managed to produce specific services, and thus could be viewed as highly artificial or controlled. Yet all constructed ecosystems exhibit spontaneous dynamics, as community structure changes due to internal or external ecological processes. While all green roofs have some element of design and human control over ecological trajectories, the level of ongoing management can vary greatly. I discuss “wildness” as a characteristic of green roofs in response to their spontaneous dynamics after initial setup, and their potential to provide ecosystem services related to human psychological well-being, aesthetics and habitat for biodiversity. This approach suggests new design possibilities in interaction with spontaneous ecosystem dynamics and highlights a need for greater ecological understanding of green roof systems.