Patterning the distribution of threatened crayfish and their exotic analogues using self-organizing maps

Dorothée Kopp (1) , Frédéric Santoul (1) , Nicolas Poulet (2) , Arthur Compin (1) , Régis Céréghino (1)

1 LEFE - Laboratoire Ecologie Fonctionnelle et Environnement
2 ONEMA - Office national de l'eau et des milieux aquatiques

Ability to demonstrate statistical patterns of distribution by threatened species and by their potential competitors will determine success in forecasting locations at greatest risk, and ability to target management efforts. A self organizing map algorithm (SOM) was used to derive probabilities of presence of native (Austropotamobius pallipes) and exotic (Orconectes limosus, Pacifastacus leniusculus and Procambarus clarkii) crayfish species with respect to physical and landcover variables in a large stream system, using a simple presence-absence data set of species. Crayfish were sampled at 128 sites representing 86 rivers. The probability of occurrence of the native species increased at higher elevations above sea level and lower temperatures; populations appeared to be mostly confined to headwater streams where exotic competitors were unable to with stand the colder conditions. The distribution of exotic species was correlated with anthropogenic factors, such as the degree of urbanization and agricultural land area. Complementary modelling tools, such as GIS and SOMs, can help to maximize the information extracted from available data in the context of biological conservation.

Mots clés: Freshwater; Land use; Neural networks; Occurrence; Species distribution

Domaines: Biodiversité et Ecologie; Zoologie des invertébrés; Ecosystèmes

Dorothée Kopp, Frédéric Santoul, Nicolas Poulet, Arthur Compin, Régis Céréghino. Patterning the distribution of threatened crayfish and their exotic analogues using self-organizing maps. Environmental Conservation, 2010, vol. 37, pp. 147-154. ⟨10.1017/S0376892910000378⟩. ⟨hal-00910873⟩