Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: João Campos x
  • Search level: All x
Clear All

The West African crocodile (Crocodylus suchus) is an emblematic species from the Sahara-Sahel with scarce knowledge on distribution and conservation status. This study updated the knowledge on distribution, occupied habitats, population size, and factors that threaten C. suchus and its habitats in Mauritania. Five field expeditions to Mauritania (2011-2016), allowed the detection of 26 new localities, increasing by 27% the current number of all known locations (adding up to N=96). In most localities less than five individuals were observed, and in all visiting sites the number of observed individuals ranged from one to 23. Eleven threat factors were identified, being droughts and temperature extremes (100% localities affected) and water abstraction for domestic use and nomadic grazing (94%) the most frequent. These findings suggest that crocodiles are apparently vulnerable in Mauritania and that future local conservation strategies are needed to assure the continuity of its fragile populations and preserve their habitats.

In: Amphibia-Reptilia

The Mugger Crocodile (Crocodylus palustris) is a threatened reptile inhabiting the Indian Sub-continent and Western Asia. Despite its “Vulnerable” conservation status, data about population genetic structure and connectivity are unavailable. This study makes a preliminary assessment of the genetic diversity, population structure and habitat connectivity of C. palustris in Iran. Ten tissue samples collected along the Sarbaz-Bahukalat basins were analysed and a set of 12 microsatellites was genotyped. Genetic diversity indices were estimated and population substructuring was assessed through Bayesian clustering analysis. Potential connectivity was verified through Remote Sensing water indexes, further implemented in a circuit analysis. Low genetic diversity was observed (mean observed heterozygosity = 0.35; mean expected heterozygosity = 0.43) and no population structure was found (K = 1). Water index and circuit analysis suggested possible connection among sites. This study highlights the potential vulnerability of crocodile populations and the importance of habitat connectivity for their persistence in the arid regions of Iran.

In: Amphibia-Reptilia

Agama boulengeri is a West African endemic lizard. It occurs in arid rocky areas in the Mauritanian mountains and Kayes region of Mali. Data on the distribution of Agama boulengeri is however very coarse, and the contribution of climatic and habitat factors for population isolation are unknown. Using Maxent, GLM, and high-resolution data, we generated environmental niche models, and quantified suitable areas for species occurrence. Field observations and predicted suitable areas were used to evaluate the conservation status of Agama boulengeri. Results revealed the species occurs preferentially close to gueltas, bare areas, and rocky deserts and in areas of increasing rainfall. Suitable cells were mostly located in Mauritania, and four potentially fragmented subpopulations were identified. The conservation status of Agama boulengeri was determined to be of Least Concern.

In: Amphibia-Reptilia

A precise knowledge of the spatial distribution of taxa is essential for decision-making processes in land management and biodiversity conservation, both for present and under future global change scenarios. This is a key base for several scientific disciplines (e.g. macro-ecology, biogeography, evolutionary biology, spatial planning, or environmental impact assessment) that rely on species distribution maps. An atlas summarizing the distribution of European amphibians and reptiles with 50 × 50 km resolution maps based on ca. 85 000 grid records was published by the Societas Europaea Herpetologica (SEH) in 1997. Since then, more detailed species distribution maps covering large parts of Europe became available, while taxonomic progress has led to a plethora of taxonomic changes including new species descriptions. To account for these progresses, we compiled information from different data sources: published in books and websites, ongoing national atlases, personal data kindly provided to the SEH, the 1997 European Atlas, and the Global Biodiversity Information Facility (GBIF). Databases were homogenised, deleting all information except species names and coordinates, projected to the same coordinate system (WGS84) and transformed into a 50 × 50 km grid. The newly compiled database comprises more than 384 000 grid and locality records distributed across 40 countries. We calculated species richness maps as well as maps of Corrected Weighted Endemism and defined species distribution types (i.e. groups of species with similar distribution patterns) by hierarchical cluster analysis using Jaccard’s index as association measure. Our analysis serves as a preliminary step towards an interactive, dynamic and online distributed database system (NA2RE system) of the current spatial distribution of European amphibians and reptiles. The NA2RE system will serve as well to monitor potential temporal changes in their distributions. Grid maps of all species are made available along with this paper as a tool for decision-making and conservation-related studies and actions. We also identify taxonomic and geographic gaps of knowledge that need to be filled, and we highlight the need to add temporal and altitudinal data for all records, to allow tracking potential species distribution changes as well as detailed modelling of the impacts of land use and climate change on European amphibians and reptiles.

Open Access
In: Amphibia-Reptilia