Variation in Impatiens species in Northern Western Ghats: Role of reproductive ecology and spatial distribution

Abstract

Variation, genetic or morphological, in populations of species is affected by many ecological parameters. In plant species, typically, population size, density, reproduction strategy, pollination and seed dispersal mechanisms, phenology and other life history traits are some of the major parameters. Rock outcrops provide a good system of isolated „terrestrial islands‟ to assess the interactions of these parameters with the population dynamics. Diverse species of Impatiens with different backgrounds of endemism and habitat specificity prove to be ideal for comparisons of inter-intra population variation to detect the divergence of populations. Various ecological parameters were assessed for different populations of five Impatiens species and morphological variation was measured. Important result from this study is that, I. lawii populations show dramatic differences in their reproductive traits than other species. Primary reason for this result was a restricted gene flow which could have caused by ecological determinants such as narrow geographic distribution, habitat specificity and different levels of flower visitation for different populations.