Monitoring nutrition of a large grazer: muskoxen on the Arctic Refuge

The number of young muskoxen (Ovibos moschatus) on Alaska's Arctic Refuge declined from 1986. We hypothesized that poor calf production was related to poor maternal nutrition. We analyzed samples from 40 adult females collected in 1988, 1989, 1991, 1992 and 2000. Sera and hair were depleted in N when compared with those of captive animals fed grass hay; that is, low dietary N in wild animals may result in less fractionation than in captivity. Poor nutrition in 1991 was indicated by elevation of 15N in serum, low serum Cu (0.480.05 g mL-1) and low activities of the Cu-enzyme ceruloplasmin (161 IU.L-1). Fecal enrichment of both 15N and 13C indicated a consistent diet based on graminoids that was similar between 1991 and 2000. Poor nutrition was probably associated with deep snow and low food abundance in 1990 or 1991. Forage abundance rather than quality may have the greatest influence on the populations dynamics of large grazers in highly seasonal environments. 2004 Elsevier B.V. All rights reserved.

Monitoring nutrition of a large grazer: muskoxen on the Arctic Refuge Conference Paper