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Research article2024Peer reviewedOpen access

Bear in mind! Bear presence and individual experience with calf survival shape the selection of calving sites in a long-lived solitary ungulate

Dijkgraaf, Lisa; Stenbacka, Fredrik; Cromsigt, Joris P. G. M.; Ericsson, Goran; Neumann, Wiebke

Abstract

The careful selection of ungulate calving sites to improve offspring survival is vital in the face of predation. In general, there is limited knowledge to which degree predator presence and prey's individual experience shape the selection of calving sites. Predator presence influences the spatiotemporal risk of encountering a predator, while individual experiences with previous predation events shape perceived mortality risks. We used a multi-year movement dataset of a long-lived female ungulate (moose, Alces alces, n = 79) and associated calf survival to test how predator presence (i.e., encounter risk) and females' individual experiences with previous calf mortality events affected their calving site selection and site fidelity. Using data from areas with and without Scandinavian brown bear (Ursus arctos) predation, we compared females' calving site selection using individual-based analyses. Our findings suggest two things. First, bear presence influences calving site selection in this solitary living ungulate. Females in areas with bears were selected for higher shrub and tree cover and showed lower site fidelity than in the bear-free area. Second, the individual experience of calf loss changes females' selection the following year. Females with lost calves had a lower site fidelity compared to females with surviving calves. Our findings suggest that increased vegetation cover may be important for reducing encounter risk in bear areas, possibly by improving calf concealment. Lower site fidelity might represent a strategy to make the placement of calving sites less predictable for predators. We suggest that bear presence shapes both habitat selection and calving site fidelity in a long-lived animal, whereas the effect of individual experience with previous calf loss varies. We encourage further research on the relevance of female experience on the success of expressed anti-predator strategies during calving periods.Bear presence influences the calving site selection in a solitary living ungulate like moose (Alces alces). Females' individual experience of calf loss changes their selection for a calving site the following year. Reduced calving site fidelity in bear areas, relative to the area without bears, might represent a female strategy to make the placement of calving sites less predictable for predators. Increased vegetation cover seems to be an important habitat feature for reducing calf predation risk, possibly by improving calf concealment.image

Keywords

anti-predator behavior; calf survival; glmmTMB; habitat selection; site fidelity; step selection functions

Published in

Ecology and Evolution
2024, Volume: 14, number: 3, article number: e11177Publisher: WILEY