Too hot to handle: summer space use shift in a cold-adapted ungulate at the edge of its range

Abstract

Context Global warming has been exerting an increasing stress on mammal populations occurring at the bioclimatic edges of their ranges. Moose, as heat-sensitive ungulates, are expected to be increasingly susceptible to thermal stress; however, the behavioral responses of animals could mitigate unfavorable weather conditions. Objectives We aimed to evaluate the temperaturemediated behavioral changes in moose occurring at the southwestern edge of the species' range in Europe. We predicted that increasing temperature in summer would modify the daily activity pattern of animal and fine-scale utilization of thermal cover. Methods We analysed data from 36 moose, who were fitted with GPS collars from two study sites located in Eastern Poland. The distance between moose locations served for assessing moose activity. We applied additive modelling to test the effect of the daily temperature on daily activity patterns and landscape use of moose. Results Moose, when exposed to temperatures exceeding thermal comfort, increased their activity during cooler twilight hours. On the hottest days, moose were more likely to use tree canopy cover, especially during midday hours. Finally, with increased temperatures and the risk of thermal stress, at that part of the day, moose utilized denser forest stands which could have provided extra protection against solar radiation. Conclusions Our observations suggested that under a scenario of further climate warming, moose at the southwestern periphery of their range will be forced to make further behavioral alterations. However, it is not clear whether they will be able to compensate for the negative effects of on-going climate change.

Habitat use as indicator of adaptive capacity to climate change

“…This difference in effect size could stem from higher average temperatures in Massachusetts, differences in habitat availability in the two states, or differences in sex ratios of the GPS‐collared moose in the two datasets (i.e., female bias in Adirondacks, male bias in Massachusetts; Ofstad et al., 2019). This temperature‐dependent habitat selection could be beneficial by reducing energy expenditure for thermoregulation and is consistent with observations of moose habitat selection for forested wetlands in the Northeast (Wattles et al., 2018a) and selection for dense‐canopy forests as thermal refuges in Europe (Borowik et al., 2020; Melin et al., 2014; van Beest & Milner, 2013).…”

“…The capacity to adapt to warmer temperatures could allow moose to survive and persist in the Northeast currently and into the future. Prior estimates of thermal thresholds for moose were derived from a small number of captive individuals from cooler regions (McCann et al., 2013; Renecker & Hudson, 1986), so these estimates could prove inaccurate in the Northeast if moose are adapted to regional temperatures (Borowik et al., 2020; McCann et al., 2013). Geographic differences in coat characteristics or body size could alter thermal tolerances (Herfindal et al., 2014; Hoy et al., 2018).…”

Gastrointestinal Helminths of a European Moose Population in Poland

“…were probably accidentally isolated from the duodenum. Of the two, Ashworthius sidemi merits particularly close monitoring, as it is a new parasite in central Europe [ 20 ], and the moose population includes a significant percentage of migratory individuals [ 7 ]. In the present study, the presence of Haemonchinae infection appeared to predispose the host to higher counts of other abomasal parasites, and thus could worsen the course of parasitic infections, as previously observed in other moose parasites [ 21 , 22 ].…”

“…A combination of high intensity of infection and broad parasite species diversity might also significantly impact host health status [ 4 , 5 ]. Ruminants exposed to certain environmental risk factors, such as climate change or high population density, may be particularly susceptible to increasing parasite pressure [ 2 , 6 , 7 ].…”

“…As heat-sensitive ungulates, moose are particularly susceptible to the effects of global warming [ 7 ]. Therefore, being present at high densities, the relatively high-density moose population in Poland presents a unique opportunity to study parasitic infections and host-parasite relationships.…”