When the method for mapping species matters: defining priority areas for conservation of African freshwater turtles

Abstract

Aim Defining priority areas for conservation is essential to minimize biodiversity loss, but the adoption of different methods for describing species distributions influences the outcomes. In order to provide a robust basis for the conservation of freshwater turtles in Africa, we compared the effect that different species‐mapping approaches had on derived patterns of species richness, species vulnerability and protected‐area representativeness.Location Africa.Methods We adopted three different approaches with increasing complexity for generating species distribution maps. The first approach was based on the geographic intersection of species records and grid squares; the second on the union of local convex polygons; and the third on inductive distribution modelling techniques. We used distribution maps, generated using these three approaches, to determine conservation priorities based on geographic patterns of species richness and vulnerability, as well as for conducting gap and irreplaceability analyses.Results We obtained markedly different distribution maps using the three methods, which in turn caused differences in conservation priorities. The grid‐square approach underestimated range sizes and species richness, while the polygon approach overestimated these attributes. The distribution modelling approach provided the most realistic outcome in terms of diversity patterns, by minimizing both commission and omission errors. An integrated map of conservation priority – derived by combining individual measures of priority based on the distribution modelling approach – identified the Gulf of Guinea coast and the Albertine Rift as major priority areas.Main conclusions Each species‐mapping approach has both advantages and disadvantages. The choice of the most appropriate approach in any given situation depends on the availability of locality records and on the relative importance of mitigating omission and commission errors. Our findings suggest that in most circumstances, the use of distribution modelling has many advantages relative to the other approaches. The priority areas identified in this study should be considered for targeting efforts to conserve Africa freshwater turtles in the coming years.

VegDunes – a coastal dune vegetation database for the analysis of Italian EU habitats

“…To analyse the spatial distribution of Italian coastal EU habitats contained in VegDunes, the information associated with each relevé was transferred into a 10 km x 10 km UTM grid, which is the spatial resolution most commonly used in regional and national analyses (Hassall & Thompson 2010), using a GIS software (ESRI Inc. 2006). Grid squares are commonly used to analyse habitats and species distribution patterns because this simple method is applicable to any amount of data (Bombi et al 2011). In fact, information on the habitat types and species listed in the Annexes of the Habitats Directive (EEC 1992) has been aggregated at European level and organised on the UTM grid (European Commission 2008).…”

Conservation of Mediterranean otters: the influence of map scale resolution

“…Typically resource selection functions are used to map suitable habitat based on predicted probability of use but the spatial resolution selected to obtain data to enter the models influences the accuracy of predictions (Meyer and Thuiller 2006;Baker et al 2007) and does not affect models equally across regions, techniques, or species types (Carter et al 2006;Guisan et al 2007). Consequently, failure to consider and select the most appropriate scale or suite of scales (domain) may lead to incorrect interpretations of data and consequently the mismanagement of critical natural resources (Bowyer and Kie 2006;Bombi et al 2011).…”

Spatial Turnover and Knowledge Gaps for African Chelonians Mirror those of African Small Mammals: Conservation Implications

“…Previous studies indicated the countries in the Gulf of Guinea coast, the Guinea-Congo rain forest region, and the Albertine Rift to be the most important areas of the African continent in terms of freshwater turtle species richness [18,10], whereas South Africa is the most relevant area for the terrestrial species [18]. Our study revealed that, in terms of relative uniqueness (due to lower rates of spatial turnover at country level), some of the Gulf of Guinea countries (i.e.…”

“…In Sub-Saharan Africa, turtles and tortoises are exposed to several threats, including intense hunting for food and traditional medicine, habitat loss, collection for the pet trade, etc. [8][9]; however, global studies analyzing their ecological and biogeographic patterns at the African continent scale and the implications for conservation, have been rarely performed [9][10].…”