Habitat structure mediates vulnerability to climate change through its effects on thermoregulatory behavior

Abstract

Tropical ectotherms are thought to be especially vulnerable to climate change because they are thermal specialists, having evolved in aseasonal thermal environments.However, even within the tropics, habitat structure can influence opportunities for behavioral thermoregulation. Open (and edge) habitats likely promote more effective thermoregulation due to the high spatial heterogeneity of the thermal landscape, while forests are thermally homogenous and may constrain opportunities for behavioral buffering of environmental temperatures. Nevertheless, the ways in which behavior and physiology interact at local scales to influence the response to climate change are rarely investigated. We examined the thermal ecology and physiology of two lizard species that occupy distinct environments in the tropics. The brown anole lizard (Anolis sagrei) lives along forest edges in The Bahamas, whereas the Panamanian slender anole (Anolis apletophallus) lives under the canopy of mature forests in Panama. We combined detailed estimates of environmental variation, thermoregulatory behavior, and physiology to model the vulnerability of each of these species.Our projections suggest that forest-dwelling slender anoles will experience severely reduced locomotor performance, activity time, and energy budgets as the climate warms over the coming century. Conversely, the forest-edge-dwelling brown anoles may use behavioral compensation in the face of warming, maintaining population viability for many decades. Our results indicate that local habitat variation, through its effects on behavior and physiology, is a major determinant of vulnerability to climate change. When attempting to predict the impacts of climate change on a given population, broad-scale characteristics such as latitude may have limited predictive power.

Species-Specific Expression of Growth-Regulatory Genes in 2 Anoles with Divergent Patterns of Sexual Size Dimorphism

“…2020 ; Logan et al. 2021 ; Neel et al. 2021 ), some of which can be impacted by testosterone in other species ( Lovern et al.…”

Climate anomalies and competition reduce establishment success during island colonization

“…Our methodology for measuring local environmental temperature distributions for slender anoles has been reported in detail elsewhere (Cox et al, 2020; Logan et al, 2021; Neel et al, 2021). In brief, we coated iButton temperature loggers (calibrated at factory: Embedded Data Systems, Lawrenceburg, KY, USA) in PlastiDip (PlastiDip International, Blaine, MN, USA) for waterproofing and then glued them to a short piece of wooden trim.…”

“…We caught adult lizards (>38 mm snout‐vent‐length, or “SVL”) either by hand or with a lizard catch‐pole (fishing rod and line with a slipknot). Lizards were transported to the Smithsonian facility in Gamboa for morphological, physiological, and genetic sampling procedures that were associated with other projects (Cox et al, 2020; Logan et al, 2021; Neel et al, 2021). In captivity, lizards were housed in small plastic terraria for a maximum of 48 h. We included a balled‐up piece of paper towel saturated with water as a source of humidity within each terrarium.…”

“…Our methodology for measuring local environmental temperature distributions for slender anoles has been reported in detail elsewhere (Cox et al, 2020;Logan et al, 2021;Neel et al, 2021).…”

Biological mechanisms matter in contemporary wildlife conservation

“…For instance, thermal physiology and behavioral measurements together lead to more informed ways to monitor Pseudogymnoascus destructans infection (i.e., white nose syndrome) in wild bat colonies. 85 Further, morphology, physiology, and behavior interact to permit or constrain performance within environmental contexts; 86 thus, considering this interconnectedness can provide information on critical habitat requirements and future vulnerability (e.g., to climate change 87 , 88 , 89 ). Studying these form-function relationships can therefore determine areas for protection based on species’ tolerances 83 , 90 or identify potential stocking or translocation locations incorporated, for example, into programs for imperiled fishes.…”