Seasonal foraging strategies of Alaskan gray wolves (Canislupus) in an ecosystem subsidized by Pacific salmon (Oncorhynchusspp.)

Abstract

Keyword: <i>Canis lupus</i>, <i>Oncorhynchus</i> spp., Individual specialization, Stable isotope analysis, Predator-prey interactions, Gray wolf https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Seasonal foraging strategies of Alaskan gray wolves (Canis lupus) in a salmon subsidized ecosystem A.E. Stanek (aestanek@alaska.edu) 1* , N. Wolf (nwolf@uaa.alaska.edu) 1 † , G.V. Hilderbrand (grant_hilderbrand@nps.gov) 2 ‡ , B. Mangipane (buck_mangipane@nps.gov) 3 , D. Abstract Despite frequent observations of wolves (Canis lupus L., 1758) using non-ungulate prey, the seasonal and inter-annual variation in the use and relative importance of alternative prey sources to gray wolf diets have not been studied at the individual scale. We used stable isotope analysis (δ 13 C and δ 15 N) of guard hair and blood components (clot and serum) collected over four years to examine the occurrence, extent, and temporal variation of salmon as a food resource by both individual wolves and social groups in Lake Clark National Park and Preserve in southwestern Alaska. Our results demonstrate substantial variability in the use of salmon over time. During summer, diets of five wolves consisted of at least 50% salmon while the diets of 17wolves consisted of primarily terrestrial prey. Over three years, one group of wolves consistently consumed salmon in summer and switched to terrestrial prey in winter. Prey choices were generally similar within social groups; however, the degree to which individuals consumed salmon was highly variable. The use of salmon as exhibited by wolves in Lake Clark is likely widespread where salmon are abundant and this finding should be taken into consideration in the conservation and management of wolves and their prey.

Intrapopulation variability in wolf diet revealed using a combined stable isotope and fatty acid approach

“…Despite this, bison still contributed the most to wolf diet in PPBL, suggesting that highly mobile wolves accessed bison in other areas before being harvested in the PPBL. Although contrary to our expectations, it is perhaps unsurprising that wolf diet did not match prey availability, as wolves commonly display preferential selection of certain prey species over others (Potvin and Jolicoeur 1988, Huggard 1993b, Smith et al 2004, Merkle et al 2017, Stanek et al 2017.…”

Predation risk and space use of a declining Dall sheep (Ovis dalli dalli) population

“…Given the individual variation in isotopic signatures among this population, it is likely that some wolves rely more on Dall sheep than others. Variation in the diet of wolves can be a consequence of some individuals specializing on certain prey [21,62]. Specialized predators, however, can lead to stochastic predation events that may adversely affect mountain sheep populations [63].…”

The strength of ecological subsidies across ecosystems: a latitudinal gradient of direct and indirect impacts on food webs

“…In addition, a match in the peak abundance of allochthonous and in situ prey, although seldom monitored (but see Nakano & Murakami ; Stanek et al . ), would also represent a type of temporal variability whose impact on indirect effects could be studied through theoretical models. Consumer preference can also be a key driver of trophic dynamics and the strength of indirect effects through ecosystems as demonstrated by recent theory (van Baalen et al .…”