A fuzzy habitat suitability index for Populus euphratica in the Northern Amudarya delta (Uzbekistan)

The following environmental variables are chosen as determining parameters for habitat suitability: geomorphology, groundwater level and flooding regime (i.e. flooding frequency, timing and duration of the last flooding). Here, flooding frequency is a dynamic variable that reflects the flooding history at a given site. Collected semi-quantitative and qualitative knowledge about the impact of those variables on suitability of a site for P. euphratica is formalised using a fuzzy set approach. The resulting index is implemented in GIS and applied to a test period (1991-1999). The results are compared to the actual distribution of tugai forest in the year 2000 to check their plausibility. By these means a 'virtual expert' is created that enables a fast and simple evaluation of the habitat suitability for P. euphratica on a landscape scale. As part of an integrated simulation tool, the HSI shall support the ecological impact assessment of future water management strategies on the Northern Amudarya delta.