Space use in desert environments by guanaco (Lama guanicoe). Seasonal variation is in relation with vegetal productivity.

ACEBES, P. ; MALO, J.E. ; SUAREZ, F.; OVEJERO, R.; BORGHI, C.E; GIANNONI, S.M. & TRABA, J.

Congreso; IV World Congress on Mountain Ungulates; 2006

We describe seasonal variability in space and habitat use by a small population of guanaco (Lama guanicoe) at the driest limit of its distribution. During 2005 wet- and dry-seasons we GPS-located all guanaco observations (n=75) obtained during systematic surveys (app. 150 hours/season) through Ischigualasto-Talampaya World Heritage Site (Argentina). Plant productivity for each guanaco location (in a 250m buffer) was estimated with a Vegetation Index (V.I.) for arid sites from a LANDSAT 7 image. Results show a high seasonal overlap for the Minimum Convex Polygons (Cole Concordance Index >79%) but a much lower overlap for the 80% Kernel areas (CCI <34%). Habitat use was significantly different between seasons (chi-squared= 23.85; 9 df; p=0.0045). During wet season guanacos selected mixed jarillal (34.3%) and zampal (20.0%), while during dry season guanacos selected open (30.0%) and mix scrubland (22.5%) and treelike cacti-dominated slopes (20.0%). Satellite analysis show a concentration of guanacos on the most productive patches (ANCOVA-test, p<0.0001), being also higher the V.I. for the locations of larger groups (p=0.008). These results show guanaco´s flexibility in space use and habitat selection, and its seasonal dependence on the most productive habitats.