Population dynamics in small populations

Plant species exist as long as their populations remain viable. Population viability depends on vital rates, which are in turn affected by genetic and ecological factors. In this context, I have followed several demographic, genetic and ecological approaches to assess the population status of threatened plant species. A major goal has been to develop models that integrate these factors and their various interactions.
 
In plant conservation, the types of rarity of greatest concern are those associated with reduced geographical distribution together with high specificity to a given habitat, small number of populations and small population sizes. Species with narrow endemic distributions are more vulnerable to extinction simply because they have fewer populations than widespread species. However, in many cases each population taken individually is not intrinsically more vulnerable than those of widely distributed species.  How do small plant populations of narrow endemics  manage to show stable trends in spite of demographic, environmental and genetic  stochasticity? We have observed that the mating system along with the intrinsic longevity of the plant can play a key role in the stability of such populations.