Biodiversity and endangered, keystone and indicator species

Biodiversity means the variability of life across organisms, populations and ecosystems. The Convention on Biological Diversity treats it as one connected idea across three levels: genetic diversity within species, species diversity between species, and ecosystem diversity across habitats and ecological processes. For recruitment-level questions, the common trap is to confuse the level of variation with the scale of measurement. Genetic, species and ecosystem diversity answer what is varying; alpha, beta and gamma diversity answer at what spatial scale it is being measured.

Whittaker's framework uses alpha diversity for a local site, beta diversity for differentiation among sites, and gamma diversity for total diversity across a broader region. Species richness is the count of species, while species evenness is the balance in their relative abundance. A habitat may have many species but still be ecologically weak if one species dominates heavily. Rajasthan examples help fix the idea: Aravalli slopes, Thar desert water pulses, Keoladeo wetland communities, Sambhar's saline system and Chambal riverine belts all show different biodiversity settings.

Core takeaway: biodiversity questions usually test the difference between levels, scales, richness and evenness.