Habitat use by endangered huemul (Hippocamelus bisulcus): cattle, snow, and the problem of multiple causes

Habitat use by huemul (Hippocamelus bisulcus), an endangered deer, was stud ied at two adjacent periglacial sites of south-coastal Chile. Fiordo Tempan o (cattle site) was cattle-free in 1990, after a winter of little snow, but 20 cattle were concentrated on its 2.7 km(2) grassland in 1995, after a wi nter of deeper snow. Estero Bernardo (control site) was cattle-free and stu died in 1995 only. During spring at the cattle site, deer were observed usi ng rocky slopes both years but grassland in 1990 only. During spring at the control site, deer used rocky slopes and grassland-type habitats daily. At the cattle site, fecal pellet-group densities suggested that winter use of grassland was substantial during 1990 only, and winter use of old-growth f orest relative to grassland was much greater in 1995 than in 1990. At the c ontrol site, pellet-group densities suggested that winter use of grassland- type habitats was greater than of old-growth forest. Cattle, a concomitant increase in hunting, and snow likely contributed to habitat use differences between years at the cattle site. Although my study could not untangle the relative contributions of multiple causes, results cautiously suggest that excluding cattle from periglacial sites may be important to conserve huemu l, and that winter use of old-growth forest should be a research priority. (C) 2001 Elsevier Science Ltd. All rights reserved.