Landscape condition influences energetics, reproduction, and stress biomarkers in grizzly bears

Abstract

Environmental change has been shown to influence mammalian distribution, habitat use, and behavior; however, few studies have investigated the impact on physiological function. This study aimed to determine the influence of landscape condition on the expression of target proteins related to energetics, reproduction, and stress in grizzly bears. We hypothesized that changes in landscape condition explains protein expression. Skin biopsies were collected from free-ranging grizzly bears in Alberta, Canada from 2013–2019 (n = 86 individuals). We used an information theoretic approach to develop 11 a priori candidate generalized linear mixed models to explain protein expression. We compared models using Akaike Information Criteria (AICc) weights and averaged models with ΔAICc < 2 for each protein. Food resources, represented by increased distance to coal mines and decreased crown closure, positively influenced energetic proteins (adiponectin and alpha-1-acid glycoprotein). Proteins related to reproduction (ceruloplasmin and serpin B5) were positively associated with increased wetland and upland food resources in addition to movement, but negatively associated with increased distance to roads. One stress related protein, complement C3, was positively influenced by increased percent conifer. Given the need to detect emerging threats to wildlife, we suggest the assessment of physiological function will lead to improved monitoring of species in rapidly changing landscapes.

Evaluation of physiological stress in free‐ranging bears: current knowledge and future directions

“…Preliminary research has shown that measurable stress-induced heat shock protein Hsp70 in polar bears is positively correlated with fasting and negatively correlated with sea-ice extent (Hamilton, 2008), suggesting its use as an indicator of these food-related stressors. This is further supported by Wilson et al (2020bWilson et al ( , 2021, who identified and validated proteins from biopsied skin samples in grizzly bears and found that seasonality, year (as a proxy for environmental change), geography, conifer percentage (in complement C3 proteins), as well as a suite of biological attributes (i.e. age class, sex and age class × sex interaction) all have a strong and statistically significant influence on stress and other proteins.…”

Biomarkers of Animal Nutrition: From Seasonal to Lifetime Indicators of Environmental Conditions

“…Set points can be influenced, in part, by environmental factors that determine the somatic reserves necessary to meet long-term metabolic requirements within the context of the system within which an animal resides [ 16 ]. Nutritional indices may differ dramatically across populations—how animals catabolize and accrete resources to meet energetic and metabolic demands may indicate the synchronization of an animal’s physiology with its environment.…”

“…Elsewhere, biomarkers have been used as proxies to make inferences regarding physiological states and nutritional conditions [ 14 , 15 , 16 ]. Biomarkers can reveal the underlying drivers of behavior, fitness, and responses to environmental change.…”

Untapped potential of physiology, behaviour and immune markers to predict range dynamics and marginality

“…Similarly, landscape features, movement, and disturbance together predict physiological state in grizzly bears (Wilson et al, 2021).…”

“…For example, brown bears ( Ursus arctos) near human settlements have lower heart rate variability, a cardiovascular indicator of stress, and they move further during increased human activity, which is expected to have an energetic cost (Støen et al, 2015). Similarly, landscape features, movement, and disturbance together predict physiological state in grizzly bears (Wilson et al, 2021).…”