Bat winter foraging habitat use in working forests: a multispecies spatial occupancy approach

Abstract

Insectivorous bats in temperate zones have evolved strategies such as migration or hibernation to overcome challenges of reduced resource availability and increased energy demand during winter. In the southeastern United States Coastal Plain, bats are either year‐round residents and remain active during winter or are migrants from colder areas seeking milder temperatures. Southeastern Coastal Plain forests also may represent important areas for remnant populations of species impacted by white‐nose syndrome. Working pine (Pinus spp.) forests comprise a large proportion of southeastern Coastal Plain forests, yet winter bat habitat associations and how forest management affects bat use remain understudied. Hence, we used hierarchical multispecies spatial occupancy models to evaluate factors influencing winter bat occupancy and foraging habitat associations in working forests of the southeastern Coastal Plain. From January to March 2020–2022, we deployed Anabat Swift acoustic detectors and measured site‐ and landscape‐level covariates on six working landscapes. We detected five species of bats and three species groups at 93% (224/240) of sites. We observed higher species richness at sites with high proportions of contiguous forest and low levels of basal area. At the species level, occupancy patterns were influenced by site and landscape covariates, which had varying effects on species with distinct foraging strategies. Temperature was an important predictor of detectability. Our findings offer new insights into the ecology of bats in working forest landscapes during winter, where we highlight positive responses in occupancy with contiguous forests and lower levels of basal area, as in previous summer work. By providing valuable information on winter community composition and foraging habitat associations, we hope to guide management decisions for forest attributes important to these species, thus increasing conservation opportunities within working forests.

Winter diet of bats in working forests of the southeastern U.S. Coastal Plain

“…The remaining bat species in our study are smaller and adapted to foraging along forest edges or within forests e.g., 22 , 55 , 56 . Lasiurus borealis and L. seminolus share similar ecomorphologies, to the point that it is difficult to separate them by the characteristics of their echolocation calls or external morphology 57 , 58 .…”

“…However, we observed numerous Coleoptera OTUs present in the diet of M. austroriparius, which highlights its dietary plasticity, consuming hard-bodied insects in winter. Differences between M. austroriparius with diets of L. seminolus and N. humeralis suggest a tendency towards a more specialized diet likely influenced by its forest-interior foraging strategies 22 . www.nature.com/scientificreports/ Perimyotis subflavus is among the smallest bats in North America 61 .…”

“…Competing vegetation was temporarily suppressed through herbicide applications, prescribed fire, or mechanically, with most stands being thinned at least once. We defined January–March as the winter sampling season, as mean nighttime temperatures are lowest (typically < 10 °C) during this time in most of the Coastal Plain region 22 .…”

“…Dietary studies focused on significant food resources and the effects of species interactions and communities are key to informing wildlife management decisions regarding species trophic position and population regulation 19 .In most temperate zones, bats migrate or remain in torpor during winter 20 . However, milder climatic conditions of southern temperate latitudes, such as the Coastal Plain of the southeastern United States (U.S.), allow bats to remain active year-round or migrate from northern latitudes seeking warmer winter temperatures 21,22 . This region is especially relevant because the ability of Coastal Plain populations to maintain higher activity throughout the winter could translate into lower mortality associated with white-nose syndrome (WNS), an epizootic, infectious fungal disease caused by Pseudogtmnoascus destructans (Pd).…”