Foxes engineer hotspots of wildlife activity on the nutrient-limited Arctic tundra

Predators largely affect ecosystems through trophic interactions, but they also can have indirect effects by altering nutrient dynamics and acting as ecosystem engineers. Arctic foxes (Vulpes lagopus) are ecosystem engineers that concentrate nutrients on their dens, creating biogeochemical hotspots with lush vegetation on the nutrient-limited tundra. Red foxes (V. vulpes) similarly engineer subarctic environments through their denning behavior, and have recently expanded onto the tundra where they now often occupy historical Arctic fox dens. We evaluated the impact of fox denning activity on the spatial behavior of other tundra wildlife by comparing predator and herbivore visits to 12 natal dens and adjacent control sites over two years using camera traps in northeastern Manitoba, where both fox species are sympatric. Both the capture rates and species richness of wildlife were significantly greater at fox dens relative to control sites. Predators were detected almost exclusively on dens occupied by foxes, where they were observed investigating and scavenging prey remains (carrion, feathers), suggesting carcass presence or fox presence attracts predators to den sites. Caribou (Rangifer tarandus) also visited dens more often than control sites, likely attracted by the enhanced vegetation typically found on dens. Our results suggest fox ecosystem engineering affects the spatial distribution of herbivores by enriching vegetation at dens, and other predators by providing carrion. Understanding how predators affect other organisms via non-trophic interactions provides an enriched view of their functional roles within ecosystems

R Code and Data Supporting: Ecological forecasts reveal limitations of common model selection methods: predicting changes in beaver colony densities

Detailed documentation in readme text file.This repository contains the R and JAGS code supporting results reported in: Johnson-Bice, S.M., J.M. Ferguson, J.D. Erb, T.D. Gable, S.K. Windels (2020). Ecological forecasts reveal limitations of common model selection methods: predicting changes in beaver colony densities. Ecological Applications [In Press].Minnesota Environment and Natural Resources Trust Fund, as recommended by the Legislative-Citizen Commission on Minnesota Resources (project M.L. 2016, Chp. 186, Sec. 2, Subd.03j)Minnesota Department of Natural ResourcesUniversity of Minnesota DuluthUniversity of Minnesota Twin Citie

Data for: Wolves alter the trajectory of forests by shaping the central-place foraging behavior of an ecosystem engineer

Dataset for Gable et al. 2023 where the authors describe how wolves indirectly alter the trajectory of forests by constraining the distance that beavers, a central place forager and prolific ecosystem engineer, forage from water. Specifically, Gable et al. demonstrate wolves wait-in-ambush and kill beavers on longer feeding trails than would be expected based on the spatiotemporal availability of beavers. This pattern is driven by temporal dynamics of beaver foraging: beavers make more foraging trips and spend more time on land per trip on longer feeding trails that extend farther from water. As a result, beavers are more vulnerable on longer feeding trails than shorter ones. Wolf predation appears to be a selective evolutionary pressure propelled by consumptive and non-consumptive mechanisms that constrain the distance from water beavers forage, which in turn limits the area of forest around wetlands, lakes, and rivers beavers alter through foraging. Thus, wolves appear intricately linked to boreal forest dynamics by shaping beaver foraging behavior, a form of natural disturbance that alters the successional and ecological states of forests.Gable, Thomas D; Johnson-Bice, Sean M; Homkes, Austin T; Fieberg, John R; Bump, Joseph K. (2023). Data for: Wolves alter the trajectory of forests by shaping the central-place foraging behavior of an ecosystem engineer. Retrieved from the University Digital Conservancy, https://doi.org/10.13020/vzn6-g462

The ethology of wolves foraging on freshwater fish in a boreal ecosystem

Through global positioning system (GPS) collar locations, remote cameras, field observations and the first wild wolf to be GPS-collared with a camera collar, we describe when, where and how wolves fish in a freshwater ecosystem. From 2017 to 2021, we recorded more than 10 wolves (Canis lupus) hunting fish during the spring spawning season in northern Minnesota, USA. Wolves ambushed fish in creeks at night when spawning fish were abundant, available and vulnerable in shallow waters. We observed wolves specifically targeting sections of rivers below beaver (Castor canadensis) dams, suggesting that beavers may indirectly facilitate wolf fishing behaviour. Wolves also cached fish on shorelines. We documented these findings across five different social groups at four distinct waterways, suggesting that wolf fishing behaviour may be widespread in similar ecosystems but has probably remained difficult to study given its annual brevity. Spawning fish may serve as a valuable pulsed resource for packs because the spring spawning season coincides with low primary prey (deer Odocoileus virginianus) availability and abundance, and when packs have higher energetic demands owing to newly born pups. We demonstrate the flexibility and adaptability of wolf hunting and foraging behaviour, and provide insight into how wolves can survive in a myriad of ecosystems