Long‐term changes in habitat selection and prey spectrum in a reintroduced Eurasian lynx (Lynx lynx) population in Switzerland

Abstract

When wild‐caught Eurasian lynx (Lynx lynx) from the Slovak Carpathian Mountains were reintroduced to Central Switzerland in the early 1970s and spread through the north‐western Swiss Alps (NWA), they faced a largely unfamiliar landscape with strongly fragmented forests, high elevations, and intense human land use. For more than 30 years, radio‐collared lynx have been monitored during three different project periods (in the 1980s, 1990s, and 2010s). Our study explored, how lynx over generations have learned to adjust to the alpine environment. We predicted that (1) lynx nowadays select more strongly for open habitats, higher elevations, and steep slopes compared to the early stages of recolonization and that (2) consequently, there were significant changes in the Eurasian lynx’ prey spectrum. To test our predictions, we analyzed telemetry data (VHF, GPS) of 13 adult resident lynx in the NWA over 35 years, using Resource Selection Functions. Furthermore, we compared kills recorded from different individuals inhabiting the same region during three project periods. In general, lynx preferred forested areas, but over the years, they avoided open habitat less. Compared to the early stage of the recolonization, lynx in the most recent project period selected for higher elevations and the proportion of chamois in their prey spectrum surmounted that of roe deer. Potential driving factors for the observed changes could be increasing tolerance to human presence, intraspecific competition, or fitness benefits through exploitation of new resources. Long‐term studies like ours provide important insight into how animals can respond to sudden environmental changes, e.g., in the course of translocations into new areas or anthropogenic alterations of their habitats.

Integrating animal tracking datasets at a continental scale for mapping Eurasian lynx habitat

“…While VHF data (225/442 remaining individuals) offered lower positional accuracy compared to GPS data (location errors up to ca. 500 m; Nagl et al., 2022; White et al., 2015), we included them to improve the representativity of our datasets for characterizing site‐ and continental‐scale habitat selection by lynx.…”

Sex‐specific differences and long‐term trends in habitat selection of American woodcock

“…Because we wanted to make probability of use predictions for 2 of our analyses (objectives 2, 3) and check that our models were not overfit, we ensured that each of the top models (ΔAIC c ≤ 2) from the 3 analyses had high predictive power and performed well on both training and test datasets before model averaging as indicated by a moderately high Spearman rank correlation coefficient ( r s ≥ 0.6; Boyce et al 2002). We performed a 5‐fold cross validation where we withheld 20% of the data in each fold using the function kfoldRSF () in the package IndRSA (Boyce et al 2002, Bastille‐Rousseau and Wittemyer 2019, Bastille‐Rousseau et al 2020, Nagl et al 2022). Each of the 4 female top models from objective 2 and the 2 male top models from objective 3 performed well at predicting woodcock habitat selection so we continued with model averaging of coefficient estimates.…”