Towards a generalisation of the spatial species mingling diversity index

Species diversity is an important notion of all ecosystems and much contributes to its inner functioning. Currently biodiversity is threatened by global changes including climate change. Spatial species mingling is a refinement of species diversity considering how individual plants of varying species are spatially mixed with those of others in local neighbourhoods. An important objective of conservation is to halt or at least to retard species diversity loss. A key element of monitoring systems, which can establish imminent threats to species, are reliable indices quantifying diversity. In this study, we proposed a generalised spatial species mingling index for an improved monitoring of how individual plants of certain species spatially mix with those of other species. A key feature of our new concept is a devaluation of instances of species inequality caused by recurrent neighbour species. The devaluation uses a memory function and is derived from proportional rules in multiwinner approval voting of political science. Our detailed analysis revealed that our new species mingling index has several statistical advantages over previous index concepts and is ecologically more plausible. Whilst dealing efficiently with recurrent species among the nearest neighbours, the new index is less dependent on global and local species richness than previous indices. Additionally, the index allows for adjustments by a parameter which can freely be chosen. Based on our analysis we recommend the use of our generalised species mingling index in the monitoring of spatial species diversity.