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Newediuk L, Mastromonaco GF, Vander Wal E. Associations between glucocorticoids and habitat selection reflect daily and seasonal energy requirements. Mov Ecol 2024; 12:30. [PMID: 38649956 PMCID: PMC11036748 DOI: 10.1186/s40462-024-00475-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 04/14/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Glucocorticoids are often associated with stressful environments, but they are also thought to drive the best strategies to improve fitness in stressful environments. Glucocorticoids improve fitness in part by regulating foraging behaviours in response to daily and seasonal energy requirements. However, many studies demonstrating relationships between foraging behaviour and glucocorticoids are experimental, and few observational studies conducted under natural conditions have tested whether changing glucocorticoid levels are related to daily and seasonal changes in energy requirements. METHODS We integrated glucocorticoids into habitat selection models to test for relationships between foraging behaviour and glucocorticoid levels in elk (Cervus canadensis) as their daily and seasonal energy requirements changed. Using integrated step selection analysis, we tested whether elevated glucocorticoid levels were related to foraging habitat selection on a daily scale and whether that relationship became stronger during lactation, one of the greatest seasonal periods of energy requirement for female mammals. RESULTS We found stronger selection of foraging habitat by female elk with elevated glucocorticoids (eß = 1.44 95% CI 1.01, 2.04). We found no difference in overall glucocorticoid levels after calving, nor a significant change in the relationship between glucocorticoids and foraging habitat selection at the time of calving. However, we found a gradual increase in the relationship between glucocorticoids and habitat selection by female elk as their calves grew over the next few months (eß = 1.01, 95% CI 1.00, 1.02), suggesting a potentially stronger physiological effect of glucocorticoids for elk with increasing energy requirements. CONCLUSIONS We suggest glucocorticoid-integrated habitat selection models demonstrate the role of glucocorticoids in regulating foraging responses to daily and seasonal energy requirements. Ultimately, this integration will help elucidate the implications of elevated glucocorticoids under natural conditions.
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Affiliation(s)
- Levi Newediuk
- Department of Biology, Memorial University, St. John's Newfoundland, A1B 3X9, Canada.
- Current address: Biological Sciences Department, University of Manitoba, Winnipeg Manitoba, R3T 2N2, Canada.
| | | | - Eric Vander Wal
- Department of Biology, Memorial University, St. John's Newfoundland, A1B 3X9, Canada
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Collins SM, Hendrix JG, Webber QMR, Boyle SP, Kingdon KA, Blackmore RJ, d'Entremont KJN, Hogg J, Ibáñez JP, Kennah JL, Lamarre J, Mejías M, Newediuk L, Richards C, Schwedak K, Wijekulathilake C, Turner JW. Bibliometric investigation of the integration of animal personality in conservation contexts. Conserv Biol 2023; 37:e14021. [PMID: 36285603 DOI: 10.1111/cobi.14021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 09/15/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Consistent individual differences in behavior, commonly termed animal personality, are a widespread phenomenon across taxa that have important consequences for fitness, natural selection, and trophic interactions. Animal personality research may prove useful in several conservation contexts, but which contexts remains to be determined. We conducted a structured literature review of 654 studies identified by combining search terms for animal personality and various conservation subfields. We scored the relevance of personality and conservation issues for each study to identify which studies meaningfully integrated the 2 fields as opposed to surface-level connections or vague allusions. We found a taxonomic bias toward mammals (29% of all studies). Very few amphibian or reptile studies applied personality research to conservation issues (6% each). Climate change (21%), invasive species (15%), and captive breeding and reintroduction (13%) were the most abundant conservation subfields that occurred in our search, though a substantial proportion of these papers weakly integrated conservation and animal personality (climate change 54%, invasive species 51%, captive breeding and reintroduction 40%). Based on our results, we recommend that researchers strive for consistent and broadly applicable terminology when describing consistent behavioral differences to minimize confusion and improve the searchability of research. We identify several gaps in the literature that appear to be promising and fruitful avenues for future research, such as disease transmission as a function of sociability or exploration as a driver of space use in protected areas. Practitioners can begin informing future conservation efforts with knowledge gained from animal personality research.
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Affiliation(s)
- Sydney M Collins
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Jack G Hendrix
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Quinn M R Webber
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Sean P Boyle
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Katrien A Kingdon
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Robert J Blackmore
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Kyle J N d'Entremont
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Jennifer Hogg
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Juan P Ibáñez
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Joanie L Kennah
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Jessika Lamarre
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Miguel Mejías
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Levi Newediuk
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Cerren Richards
- Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Katrina Schwedak
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Chirathi Wijekulathilake
- Cognitive and Behavioural Ecology Program, Departments of Biology and Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Julie W Turner
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
- Wildlife Division, Government of Newfoundland and Labrador, Corner Brook, Newfoundland and Labrador, Canada
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Newediuk L, Bath DR. Meta-analysis reveals between-population differences affect the link between glucocorticoids and population health. Conserv Physiol 2023; 11:coad005. [PMID: 36845329 PMCID: PMC9945071 DOI: 10.1093/conphys/coad005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Glucocorticoids are a popular tool for monitoring health of animal populations because they can increase with environmental stressors and can indicate chronic stress. However, individual responses to stressors create variation in the glucocorticoid-fitness relationship within populations. The inconsistency in this relationship calls into question the widespread use of glucocorticoids in conservation. We investigated the sources of variation in the glucocorticoid-fitness relationship by conducting a meta-analysis across a diverse set of species exposed to conservation-relevant stressors. We first quantified the extent to which studies inferred population health from glucocorticoids without first validating the glucocorticoid-fitness relationship in their own populations. We also tested whether population-level information like life history stage, sex and species longevity influenced the relationship between glucocorticoids and fitness. Finally, we tested for a universally consistent relationship between glucocorticoids and fitness across studies. We found more than half of peer-reviewed studies published between 2008 and 2022 inferred population health solely based on glucocorticoid levels. While life history stage explained some variation in the relationship between glucocorticoids and fitness, we found no consistent relationship between them. Much of the variation in the relationship could be the result of idiosyncratic characteristics of declining populations, such as unstable demographic structure, that coincided with large amounts of variation in glucocorticoid production. We suggest that conservation biologists capitalize on this variation in glucocorticoid production by declining populations by using the variance in glucocorticoid production as an early warning for declines in population health.
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Affiliation(s)
- Levi Newediuk
- Corresponding author: Department of Biology, Memorial University, 45 Arctic Avenue, St. John's, Newfoundland A1B 3X9, Canada.
| | - Devon R Bath
- Department of Ocean Sciences, Memorial University, 0 Marine Lab Road, St. John's, Newfoundland A1C 5S7, Canada
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Newediuk L, Prokopenko CM, Vander Wal E. Individual differences in habitat selection mediate landscape level predictions of a functional response. Oecologia 2022; 198:99-110. [PMID: 34984521 DOI: 10.1007/s00442-021-05098-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
Predicting future space use by animals requires models that consider both habitat availability and individual differences in habitat selection. The functional response in habitat selection posits animals adjust their habitat selection to availability, but population-level responses to availability may differ from individual responses. Generalized functional response (GFR) models account for functional responses by including fixed effect interactions between habitat availability and selection. Population-level resource selection functions instead account for individual selection responses to availability with random effects. We compared predictive performance of both approaches using a functional response in elk (Cervus canadensis) selection for mixed forest in response to road proximity, and avoidance of roads in response to mixed forest availability. We also investigated how performance changed when individuals responded differently to availability from the rest of the population. Individual variation in road avoidance decreased performance of both models (random effects: β = 0.69, 95% CI 0.47, 0.91; GFR: β = 0.38, 95% CI 0.05, 0.71). Changes in individual road and forest availability affected performance of neither model, suggesting individual responses to availability different from the functional response mediated performance. We also found that overall, both models performed similarly for predicting mixed forest selection (F1, 58 = 0.14, p = 0.71) and road avoidance (F1, 58 = 0.28, p = 0.60). GFR estimates were slightly better, but its larger number of covariates produced greater variance than the random effects model. Given this bias-variance trade-off, we conclude that neither model performs better for future space use predictions.
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Affiliation(s)
- Levi Newediuk
- Department of Biology, Memorial University, St. John's, NL, A1B 3X9, Canada.
| | | | - Eric Vander Wal
- Department of Biology, Memorial University, St. John's, NL, A1B 3X9, Canada
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