Assessing genetic diversity and population structure for prioritizing conservation of the critically endangered Great Indian Bustard (Aredotis nigriceps)

Abstract

The critically endangered Great Indian Bustard Ardeotis nigriceps (GIB) is on the verge of imminent extinction, and exists as fragmented populations with 100–150 birds in India and a few in neighbouring Pakistan. Rajasthan holds the largest population of ∼128 birds, Gujarat has ∼5, and Maharashtra-Karnataka-Andhra Pradesh having ∼10 birds. Their range and abundance have reduced by 90% within last 50 years, primarily due to hunting, habitat loss to agriculture and industry, and power-line collisions. Conservation agencies are implementing habitat protection/restoration and conservation breeding as insurance against extinction and for future reintroductions/supplementation. To guide these ongoing in-situ and ex-situ conservation measures, we examined patterns of genetic diversity, population structure, bottlenecks and dispersal using microsatellite and mitochondrial markers. Analyses of 73 individual GIB revealed low mt-DNA (h=0.554, π = 0.001) and microsatellite diversity (Ho=0.32). Bayesian clustering analysis identified three genetic populations. Migration between these populations was low and asymmetric, highest being from Rajasthan into Maharashtra (9%) and Madhya Pradesh (4%), perhaps due to extreme habitat fragmentation and small numbers. Rajasthan population encompassed the maximum genetic diversity, that along with its large size and availability of breeders, made it ideal for sourcing founders for conservation breeding. However, the presence of private alleles in other populations implies that additional sourcing of birds from Andhra Pradesh and Gujarat may be required to capture the extant gene pool of GIB in captive founder population.

Keywords

• Small population
• Microsatellites
• Genetic diversity
• Founders
• Conservation priority