Droppings as crystal balls. DNA-based estimates

MORÁN, M; FAMELI, A; BLANCO-FONTAO, B; QUEVEDO, M; MIROL, P; BAÑUELOS, MJ

Glasgow

Congreso; 3rd European Congress of Conservation Biology ? ECCB; 2012

Counting rare, elusive animals, and assessing the extent of their movements in the wild, are basic yet challenging issues. We set out to estimate population size and movements between breeding territories for an endangered population of grouse, Cantabrian capercaillies living in NW Spain. These elusive birds live in rugged, forested habitats; capturing and handling them is not allowed, thus genetic identification of feces could be the only way of gathering the much needed data. We collected droppings as source of DNA in the vicinity of 25 leks, areas where capercaillie gather in spring to display and mate. We genotyped 141 droppings, and identified 89 individuals from 7-9 microsatellite loci in a 110 km2 study area. We estimated a population size of 234 individuals with a single-session capture-mark-recapture model (156-252 95% CI; recapture rate = 1.6 obs/indv.). Fourteen individuals were identified more than once. Remarkably, distances among samples of the same individual showed movements shorter than 1 km, always within or between contiguous leks. Our results show that genetic identification of indirect signs of presence is a reliable tool to estimate population size and range of movements for relatively small, elusive forest vertebrates.