Socio-economic drivers and non-indigenous freshwater crayfish species in Europe

Non-indigenous freshwater crayfish species (NICS) outnumber the indigenous ones in many European countries, representing a major threat to biodiversity via the spread of crayfish 'plague' and aggressive invasion and antagonism performance. Although the biological basis of this situation is well studied, the possible role of social, economic and demographic factors on this situation has been ignored. In an attempt to explore such relationships, we suggest that human population density and economic growth (measured as gross domestic product (GDP) per capita) are positively related to the increased number of NICS in the EU area. Moreover, this pattern is evident in countries with higher overall footprint (i.e. the human demand of biologically productive land and sea in global hectares required to provide resources and services on waste assimilation) compared to biocapacity. Within the above context, actions are urgently needed to restore/balance existing and projected metabolic rifts (i.e. ruptures in the normal metabolic processes in natural systems) created by the presence of NICS.