251
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Crespi EJ, Rissler LJ, Mattheus NM, Engbrecht K, Duncan SI, Seaborn T, Hall EM, Peterson JD, Brunner JL. Geophysiology of Wood Frogs: Landscape Patterns of Prevalence of Disease and Circulating Hormone Concentrations across the Eastern Range. Integr Comp Biol 2015; 55:602-17. [PMID: 26269462 DOI: 10.1093/icb/icv096] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
One of the major challenges for conservation physiologists is to determine how current or future environmental conditions relate to the health of animals at the population level. In this study, we measured prevalence of disease, mean condition of the body, and mean resting levels of corticosterone and testosterone in a total of 28 populations across the years 2011 and 2012, and correlated these measures of health to climatic suitability of habitat, using estimates from a model of the ecological niche of the wood frog's geographic range. Using the core-periphery hypothesis as a theoretical framework, we predicted a higher prevalence and intensity of infection of Batrachochytrium dendrobatidis (Bd) and ranaviruses, two major amphibian pathogens causing disease, and higher resting levels of circulating corticosterone, an indicator of allostatic load incurred from living in marginal habitats. We found that Bd infections were rare (2% of individuals tested), while infections with ranavirus were much more common: ranavirus-infected individuals were found in 92% of ponds tested over the 2 years. Contrary to our predictions, rates of infection with ranaviruses were positively correlated with quality of the habitat with the highest prevalence at the core of the range, and plasma corticosterone concentrations measured when frogs were at rest were not correlated with quality of the habitat, the prevalence of ranavirus, or the intensity of infection. Prevalence and mean viral titers of ranavirus infection were higher in 2012 than in 2011, which coincided with lower levels of circulating corticosterone and testosterone and an extremely early time of breeding due to relatively higher temperatures during the winter. In addition, the odds of having a ranavirus infection increased with decreased body condition, and if animals had an infection, viral titers were positively correlated to levels of circulating testosterone concentration. By resolving these patterns, experiments can be designed to test hypotheses about the mechanisms that produce them, such as whether transmission of the ranavirus and tolerance of the host are greater or whether virulence is lower in populations within core habitats. While there is debate about which metrics serve as the best bioindicators of population health, the findings of this study demonstrate the importance of long-term monitoring of multiple physiological parameters to better understand the dynamic relationship between the environment and the health of wildlife populations over space and time.
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Affiliation(s)
- Erica J Crespi
- *School of Biological Sciences, Washington State University, Pullman, WA 99164, USA;
| | - Leslie J Rissler
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Nichole M Mattheus
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Kristin Engbrecht
- *School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - Sarah I Duncan
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Travis Seaborn
- *School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - Emily M Hall
- *School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - John D Peterson
- *School of Biological Sciences, Washington State University, Pullman, WA 99164, USA; Department of Biology, University of Wisconsin-Platteville, Platteville, WI 538183, USA
| | - Jesse L Brunner
- *School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
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252
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Sopinka NM, Patterson LD, Redfern JC, Pleizier NK, Belanger CB, Midwood JD, Crossin GT, Cooke SJ. Manipulating glucocorticoids in wild animals: basic and applied perspectives. CONSERVATION PHYSIOLOGY 2015; 3:cov031. [PMID: 27293716 PMCID: PMC4778459 DOI: 10.1093/conphys/cov031] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/12/2015] [Accepted: 06/15/2015] [Indexed: 05/27/2023]
Abstract
One of the most comprehensively studied responses to stressors in vertebrates is the endogenous production and regulation of glucocorticoids (GCs). Extensive laboratory research using experimental elevation of GCs in model species is instrumental in learning about stressor-induced physiological and behavioural mechanisms; however, such studies fail to inform our understanding of ecological and evolutionary processes in the wild. We reviewed emerging research that has used GC manipulations in wild vertebrates to assess GC-mediated effects on survival, physiology, behaviour, reproduction and offspring quality. Within and across taxa, exogenous manipulation of GCs increased, decreased or had no effect on traits examined in the reviewed studies. The notable diversity in responses to GC manipulation could be associated with variation in experimental methods, inherent differences among species, morphs, sexes and age classes, and the ecological conditions in which responses were measured. In their current form, results from experimental studies may be applied to animal conservation on a case-by-case basis in contexts such as threshold-based management. We discuss ways to integrate mechanistic explanations for changes in animal abundance in altered environments with functional applications that inform conservation practitioners of which species and traits may be most responsive to environmental change or human disturbance. Experimental GC manipulation holds promise for determining mechanisms underlying fitness impairment and population declines. Future work in this area should examine multiple life-history traits, with consideration of individual variation and, most importantly, validation of GC manipulations within naturally occurring and physiologically relevant ranges.
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Affiliation(s)
- Natalie M. Sopinka
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON, Canada K1S 5B6
| | - Lucy D. Patterson
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5
| | - Julia C. Redfern
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5
| | - Naomi K. Pleizier
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON, Canada K1S 5B6
| | - Cassia B. Belanger
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON, Canada K1S 5B6
| | - Jon D. Midwood
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON, Canada K1S 5B6
| | - Glenn T. Crossin
- Department of Biology, Dalhousie University, Halifax, NS, Canada B3H 4R2
| | - Steven J. Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON, Canada K1S 5B6
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253
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Hadinger U, Haymerle A, Knauer F, Schwarzenberger F, Walzer C. Faecal cortisol metabolites to assess stress in wildlife: evaluation of a field method in free‐ranging chamois. Methods Ecol Evol 2015. [DOI: 10.1111/2041-210x.12422] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ulrike Hadinger
- Research Institute of Wildlife Ecology University of Veterinary Medicine Savoyenstraße 1 1160Vienna Austria
| | - Agnes Haymerle
- Research Institute of Wildlife Ecology University of Veterinary Medicine Savoyenstraße 1 1160Vienna Austria
| | - Felix Knauer
- Research Institute of Wildlife Ecology University of Veterinary Medicine Savoyenstraße 1 1160Vienna Austria
| | - Franz Schwarzenberger
- Depatment of Biomedical Sciences – Biochemistry University of Veterinary Medicine Veterinärplatz 1 1210Vienna Austria
| | - Chris Walzer
- Research Institute of Wildlife Ecology University of Veterinary Medicine Savoyenstraße 1 1160Vienna Austria
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254
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Hunt KE, Rolland RM, Kraus SD. Conservation Physiology of an Uncatchable Animal: The North Atlantic Right Whale (Eubalaena glacialis). Integr Comp Biol 2015; 55:577-86. [DOI: 10.1093/icb/icv071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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255
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Neuman‐Lee LA, Bobby Fokidis H, Spence AR, Van der Walt M, Smith GD, Durham S, French SS. Food restriction and chronic stress alter energy use and affect immunity in an infrequent feeder. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12457] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | - H. Bobby Fokidis
- Department of Biology Rollins College Winter Park Florida 32789 USA
| | - Austin R. Spence
- Department of Biology Utah State University Logan Utah 84322 USA
| | | | - Geoffrey D. Smith
- Department of Biology Utah State University Logan Utah 84322 USA
- Ecology Center Utah State University Logan Utah 84322 USA
| | - Susan Durham
- Ecology Center Utah State University Logan Utah 84322 USA
| | - Susannah S. French
- Department of Biology Utah State University Logan Utah 84322 USA
- Ecology Center Utah State University Logan Utah 84322 USA
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256
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LaDage LD. Environmental Change, the Stress Response, and Neurogenesis: Fig. 1. Integr Comp Biol 2015; 55:372-83. [DOI: 10.1093/icb/icv040] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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257
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Agricultural land use and human presence around breeding sites increase stress-hormone levels and decrease body mass in barn owl nestlings. Oecologia 2015; 179:89-101. [DOI: 10.1007/s00442-015-3318-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 04/08/2015] [Indexed: 11/27/2022]
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258
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Effects of acute restraint stress, prolonged captivity stress and transdermal corticosterone application on immunocompetence and plasma levels of corticosterone on the cururu Toad (Rhinella icterica). PLoS One 2015; 10:e0121005. [PMID: 25831055 PMCID: PMC4382218 DOI: 10.1371/journal.pone.0121005] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 02/09/2015] [Indexed: 11/19/2022] Open
Abstract
Glucocorticoid steroids modulate immunocompetence in complex ways with both immunoenhancing and immunosuppressive effects in vertebrates exposed to different stressors. Such bimodal effects have been associated with variation in duration and intensity of the stress response. Given that natural populations have been exposed to a multitude of stressors, a better understanding of the functional association between duration and intensity of the stress response, the resulting changes in glucocorticoid plasma levels and their impact on different aspects of immunocompetence emerges as a cornerstone for vertebrate conservation strategies. We investigated the effects of a restraint challenge (with and without movement restriction), long-term captivity, and transdermal corticosterone application on plasma levels of corticosterone (hereinafter referred to as CORT) and different parameters of innate immunocompetence in the male cururu toads (Rhinella icterica). We show that for R. icterica restraint for 24h proved to be a stressful condition, increasing CORT by 3-fold without consistent immunological changes. However, the application of a more intense stressor (restraint with movement restriction), for the same period, potentiated this response resulting in a 9-fold increase in CORT, associated with increase Neutrophil/Lymphocyte ratio (N:L) and a lower bacterial killing ability (BKA). Transdermal application of corticosterone efficiently mimics repeated acute stress response events, without changing the immune parameters even after 13 days of treatment. Interestingly, long-term captivity did not mitigate the stress response, since the toads maintained 3-fold increased CORT even after 3 months under these conditions. Moreover, long-term captivity in the same condition increased total leukocyte count (TLC) and generated an even greater decrease in BKA, suggesting that consequences of the stress response can be aggravated by time in captivity.
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259
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Hau M, Haussmann MF, Greives TJ, Matlack C, Costantini D, Quetting M, Adelman JS, Miranda AC, Partecke J. Repeated stressors in adulthood increase the rate of biological ageing. Front Zool 2015; 12:4. [PMID: 25705242 PMCID: PMC4336494 DOI: 10.1186/s12983-015-0095-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 01/12/2015] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Individuals of the same age can differ substantially in the degree to which they have accumulated tissue damage, akin to bodily wear and tear, from past experiences. This accumulated tissue damage reflects the individual's biological age and may better predict physiological and behavioural performance than the individual's chronological age. However, at present it remains unclear how to reliably assess biological age in individual wild vertebrates. METHODS We exposed hand-raised adult Eurasian blackbirds (Turdus merula) to a combination of repeated immune and disturbance stressors for over one year to determine the effects of chronic stress on potential biomarkers of biological ageing including telomere shortening, oxidative stress load, and glucocorticoid hormones. We also assessed general measures of individual condition including body mass and locomotor activity. RESULTS By the end of the experiment, stress-exposed birds showed greater decreases in telomere lengths. Stress-exposed birds also maintained higher circulating levels of oxidative damage compared with control birds. Other potential biomarkers such as concentrations of antioxidants and glucocorticoid hormone traits showed greater resilience and did not differ significantly between treatment groups. CONCLUSIONS The current data demonstrate that repeated exposure to experimental stressors affects the rate of biological ageing in adult Eurasian blackbirds. Both telomeres and oxidative damage were affected by repeated stress exposure and thus can serve as blood-derived biomarkers of biological ageing.
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Affiliation(s)
- Michaela Hau
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, Am Obstberg 1, 78315 Radolfzell, Germany ; Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Mark F Haussmann
- Department of Biology, Bucknell University, Lewisburg, PA 17837 USA
| | - Timothy J Greives
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, Am Obstberg 1, 78315 Radolfzell, Germany ; Department of Biological Sciences, North Dakota State University, 1340 Bolley Drive, Fargo, ND 58202 USA
| | - Christa Matlack
- Department of Biology, Bucknell University, Lewisburg, PA 17837 USA
| | - David Costantini
- Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium ; University of Glasgow, Institute of Biodiversity, Animal Health & Comparative Medicine, Glasgow, QG12 8Q UK
| | - Michael Quetting
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, Am Obstberg 1, 78315 Radolfzell, Germany ; Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - James S Adelman
- Max Planck Institute for Ornithology, Evolutionary Physiology Group, Am Obstberg 1, 78315 Radolfzell, Germany ; Department of Biological Sciences, 4092B Derring Hall, Virginia Tech, Blacksburg, VA 24061-0406 USA
| | - Ana Catarina Miranda
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany ; Max Planck Institute for Ornithology, Department of Migration and Immuno-ecology, Am Obstberg 1, 78315 Radolfzell, Germany ; Departamento de Biologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal do Maranhão, Campus do Bacanga, São Luís, Maranhão Brazil
| | - Jesko Partecke
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany ; Max Planck Institute for Ornithology, Department of Migration and Immuno-ecology, Am Obstberg 1, 78315 Radolfzell, Germany
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260
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Morris DL, Faaborg J, Washburn BE, Millspaugh JJ. Predator-induced renesting and reproductive effort in indigo buntings: more work for less pay? CONSERVATION PHYSIOLOGY 2015; 3:cou063. [PMID: 27293684 PMCID: PMC4778466 DOI: 10.1093/conphys/cou063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 12/15/2014] [Accepted: 12/21/2014] [Indexed: 06/06/2023]
Abstract
Renesting after nest predation is ultimately an adaptive response to increase productivity in birds. However, renesting also increases reproductive effort to replace lost clutches. We investigated the consequences of this increased reproductive effort by determining whether renesting in female indigo buntings (Passerina cyanea) is associated with a decline in body condition (size-corrected mass) and haematocrit and an increase in stress hormones and whether renesting or maternal body condition is associated with a decline in productivity (clutch size, nestling body condition). Next, because a consequence of multiple renesting attempts is a prolonged breeding season and later timing, we predicted that a population of post-breeding females and juveniles would have lower body condition in fragmented forest than in contiguous forest owing to higher nest predation and frequency of renesting. Both forest types were settled by females of similar condition. Nest survival was lower in fragmented forest, where a higher proportion of females failed their first attempt and the breeding season was 2 weeks longer. Compared with females on their first attempt, renesting females had lower body condition and haematocrit and higher corticosterone concentrations. Lower maternal body condition was associated with higher concentrations of corticosterone, lower nestling body condition and smaller clutches. Clutch size was lower in renests and in fragmented forest. Nestling condition was lower in renests but did not vary greatly with forest type. Despite a prolonged breeding season in the fragmented forest, post-breeding females and hatch-year birds were in similar condition in both forest types. Our results suggest that the indirect effects of nest predation on maternal and offspring condition pose additional individual-level costs that have not been considered in the context of fragmentation studies. We discuss how predator-induced renesting could have additional demographic consequences by prolonging the breeding season and prompting seasonal interactions or carry-over effects that could impact populations.
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Affiliation(s)
- Dana L Morris
- Division of Biological Sciences, University of Missouri, 110 Tucker Hall, Columbia, MO 65211, USA
- Division of Science, Mathematics and Computer Science, Central Methodist University, 411 Central Methodist Square, Fayette, MO 65248, USA
| | - John Faaborg
- Division of Biological Sciences, University of Missouri, 110 Tucker Hall, Columbia, MO 65211, USA
| | - Brian E Washburn
- Department of Fisheries and Wildlife Sciences, University of Missouri, 302 Anheuser-Busch Natural Resources Building, Columbia, MO 65211, USA
- United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, 6100 Columbus Avenue, Sandusky, OH 44870, USA
| | - Joshua J Millspaugh
- Department of Fisheries and Wildlife Sciences, University of Missouri, 302 Anheuser-Busch Natural Resources Building, Columbia, MO 65211, USA
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261
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Majchrzak YN, Mastromonaco GF, Korver W, Burness G. Use of salivary cortisol to evaluate the influence of rides in dromedary camels. Gen Comp Endocrinol 2015; 211:123-30. [PMID: 25452030 DOI: 10.1016/j.ygcen.2014.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 10/02/2014] [Accepted: 11/05/2014] [Indexed: 10/24/2022]
Abstract
Animals in captivity and in the wild face numerous challenges, including the risk of enduring acute or chronic stress. In captivity, facilities attempt to alleviate the risk of chronic stress by providing environmental enrichment, shown to minimize behavioral disorders and stress in several species. One potential form of enrichment in zoos is training animals to provide rides for guests, however, the effect of this activity on the welfare of individual animals has never been examined. We validated the use of saliva for assessing stress in dromedary camels (Camelus dromedarius), an animal commonly used for rides. We then measured variation in salivary cortisol in four male camels while providing rides of differing frequency for guests at the Toronto Zoo. The camels were sampled during the ride season (June to September) using four treatments: (1) in their pasture, (2) at the ride area when not performing rides, (3) while providing a low number of rides (n=50/day) and (4) while providing a high number of rides (n=150/day). Furthermore, samples were taken before and after the ride season for comparison. There was a significant difference between the post-ride season treatment and the three treatments involving guest presence during the ride season (ride area, low rides, high rides). In general, cortisol concentrations were lower during the ride season and higher during the non-ride season. Based on the metrics we used, performing rides is not a stressful experience for these dromedary camels and suggests that rides may be a form of enrichment.
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Affiliation(s)
- Yasmine N Majchrzak
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
| | - Gabriela F Mastromonaco
- Environmental and Life Sciences Department, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada
| | - Wendy Korver
- Bowmanville Zoological Park, 340 King St. E, Bowmanville, Ontario L1C 3K5, Canada
| | - Gary Burness
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
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262
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Romero LM, Platts SH, Schoech SJ, Wada H, Crespi E, Martin LB, Buck CL. Understanding stress in the healthy animal - potential paths for progress. Stress 2015; 18:491-7. [PMID: 26365223 DOI: 10.3109/10253890.2015.1073255] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Although stress is usually associated with disease, the physiological and behavioral responses to stressors are critical mechanisms of resilience for healthy organisms. A recent workshop comprised of researchers who study healthy humans and both free-living and captive non-human animals identified a number of key roadblocks that are impeding progress in understanding how stress responses integrate into the normal physiology of an animal. These include the lack of: (1) an unambiguous definition of a stress phenotype; (2) a robust biomarker, or suite of biomarkers, to indicate that phenotype; (3) theoretical and quantitative models to predict how humans and other animals will react to stressors; (4) a comprehensive understanding of how individual variability in stress responses arise and (5) an understanding of the transitions between acute and chronic stress responses. Collectively, these deficiencies impair our ability to both assess the physiological status of individuals and develop procedures and techniques to reverse the effects elicited by chronic stress before they become pathological. Workshop participants also identified a number of potential approaches to facilitate progress on these problems. They include: (1) increased use of mathematical models to provide quantitative predictions; (2) use of network theory to expose emergent properties not predicted from traditional approaches; (3) development and deployment of improved sensor technology that will allow long-term, dynamic, non-invasive, multi-factor measurements of suites of stress mediators and (4) the recruitment of scientists with diverse skill sets, such as engineers, bioinformaticians, etc.; and (5) the training of young scientists in the multidisciplinary study of stress. Incorporating these approaches in new research should reinvigorate the study of stress and stimulate progress in understanding both how healthy humans cope with stressors and how other animals, including free-living animals, cope with stressors in a rapidly changing environment.
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Affiliation(s)
| | - Steven H Platts
- b Biomedical Research and Environmental Sciences Division, NASA Johnson Space Center , Houston , TX , USA
| | - Stephan J Schoech
- c Department of Biological Sciences , University of Memphis , 335 Life Sciences , Memphis, TN , USA
| | - Haruka Wada
- d Department of Biological Sciences , Auburn University , Auburn , AL , USA
| | - Erica Crespi
- e School of Biological Sciences, Washington State University , Pullman , WA , USA
| | - Lynn B Martin
- f Department of Integrative Biology , University of South Florida , Tampa , FL , USA , and
| | - C Loren Buck
- g Department of Biological Sciences , University of Alaska Anchorage , Anchorage , AK , USA
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Blake CA, Alberici da Barbiano L, Guenther JE, Gabor CR. Recognition and Response to Native and Novel Predators in the Largespring mosquitofish,Gambusia geiseri. Ethology 2014. [DOI: 10.1111/eth.12331] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chelsea A. Blake
- Department of Biology; Aquatic Resources Program; Texas State University; San Marcos TX USA
| | | | - Jessica E. Guenther
- Department of Biology; Aquatic Resources Program; Texas State University; San Marcos TX USA
| | - Caitlin R. Gabor
- Department of Biology; Aquatic Resources Program; Texas State University; San Marcos TX USA
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264
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Zanette LY, Clinchy M, Suraci JP. Diagnosing predation risk effects on demography: can measuring physiology provide the means? Oecologia 2014; 176:637-51. [PMID: 25234371 DOI: 10.1007/s00442-014-3057-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 08/18/2014] [Indexed: 11/30/2022]
Abstract
Predators kill prey thereby affecting prey survival and, in the traditional top-down view of predator limitation, that is their sole effect. Bottom-up food limitation alters the physiological condition of individuals affecting both fecundity and survival. Predators of course also scare prey inducing anti-predator defences that may carry physiological costs powerful enough to reduce prey fecundity and survival. Here, we consider whether measuring physiology can be used as a tool to unambiguously diagnose predation risk effects. We begin by providing a review of recent papers reporting physiological effects of predation risk. We then present a conceptual framework describing the pathways by which predators and food can affect prey populations and give an overview of predation risk effects on demography in various taxa. Because scared prey typically eat less the principal challenge we see will be to identify measures that permit us to avoid mistaking predator-induced reductions in food intake for absolute food shortage. To construct an effective diagnostic toolkit we advocate collecting multiple physiological measures and utilizing multivariate statistical procedures. We recommend conducting two-factor predation risk × food manipulations to identify those physiological effects least likely to be mistaken for responses to bottom-up food limitation. We suggest there is a critical need to develop a diagnostic tool that can be used when it is infeasible to experimentally test for predation risk effects on demography, as may often be the case in wildlife conservation, since failing to consider predation risk effects may cause the total impact of predators to be dramatically underestimated.
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Affiliation(s)
- Liana Y Zanette
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B7, Canada,
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265
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Bermejo-Nogales A, Nederlof M, Benedito-Palos L, Ballester-Lozano GF, Folkedal O, Olsen RE, Sitjà-Bobadilla A, Pérez-Sánchez J. Metabolic and transcriptional responses of gilthead sea bream (Sparus aurata L.) to environmental stress: new insights in fish mitochondrial phenotyping. Gen Comp Endocrinol 2014; 205:305-15. [PMID: 24792819 DOI: 10.1016/j.ygcen.2014.04.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 04/09/2014] [Accepted: 04/13/2014] [Indexed: 12/24/2022]
Abstract
The aim of the current study was to phenotype fish metabolism and the transcriptionally-mediated response of hepatic mitochondria of gilthead sea bream to intermittent and repetitive environmental stressors: (i) changes in water temperature (T-ST), (ii) changes in water level and chasing (C-ST) and (iii) multiple sensory perception stressors (M-ST). Gene expression profiling was done using a quantitative PCR array of 60 mitochondria-related genes, selected as markers of transcriptional regulation, oxidative metabolism, respiration uncoupling, antioxidant defense, protein import/folding/assembly, and mitochondrial dynamics and apoptosis. The mitochondrial phenotype mirrored changes in fish performance, haematology and lactate production. T-ST especially up-regulated transcriptional factors (PGC1α, NRF1, NRF2), rate limiting enzymes of fatty acid β-oxidation (CPT1A) and tricarboxylic acid cycle (CS), membrane translocases (Tim/TOM complex) and molecular chaperones (mtHsp10, mtHsp60, mtHsp70) to improve the oxidative capacity in a milieu of a reduced feed intake and impaired haematology. The lack of mitochondrial response, increased production of lactate and negligible effects on growth performance in C-ST fish were mostly considered as a switch from aerobic to anaerobic metabolism. A strong down-regulation of PGC1α, NRF1, NRF2, CPT1A, CS and markers of mitochondrial dynamics and apoptosis (BAX, BCLX, MFN2, MIRO2) occurred in M-ST fish in association with the greatest circulating cortisol concentration and a reduced lactate production and feed efficiency, which represents a metabolic condition with the highest allostatic load score. These findings evidence a high mitochondrial plasticity against stress stimuli, providing new insights to define the threshold level of stress condition in fish.
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Affiliation(s)
- Azucena Bermejo-Nogales
- Nutrigenomics and Fish Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain.
| | - Marit Nederlof
- Aquaculture and Fisheries Group, Wageningen University, De Elst, 6708 WD Wageningen, The Netherlands.
| | - Laura Benedito-Palos
- Nutrigenomics and Fish Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain.
| | - Gabriel F Ballester-Lozano
- Nutrigenomics and Fish Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain.
| | - Ole Folkedal
- Institute of Marine Research Matre, 5984 Matredal, Norway.
| | | | - Ariadna Sitjà-Bobadilla
- Fish Pathology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain.
| | - Jaume Pérez-Sánchez
- Nutrigenomics and Fish Growth Endocrinology Group, Department of Marine Species Biology, Culture and Pathology, Institute of Aquaculture Torre de la Sal, IATS-CSIC, 12595 Ribera de Cabanes s/n, Castellón, Spain.
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266
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Dantzer B, Fletcher QE, Boonstra R, Sheriff MJ. Measures of physiological stress: a transparent or opaque window into the status, management and conservation of species? CONSERVATION PHYSIOLOGY 2014; 2:cou023. [PMID: 27293644 PMCID: PMC4732472 DOI: 10.1093/conphys/cou023] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/08/2014] [Accepted: 05/11/2014] [Indexed: 05/18/2023]
Abstract
Conservation physiology proposes that measures of physiological stress (glucocorticoid levels) can be used to assess the status and future fate of natural populations. Increases in glucocorticoids may reflect a more challenging environment, suggesting that the influence of human activities on free-living animals could be quantified by measuring glucocorticoids. Biomedical studies suggest that chronic increases in glucocorticoids can have detrimental effects on survival and reproduction, which could influence the viability of populations. Here, we discuss the use of measurements of glucocorticoids in conservation physiology. We first provide an overview of the different methods to quantify glucocorticoids and their utility in conservation physiology. We then discuss five questions we think are essential for conservation physiologists to address. We highlight how intrinsic (e.g. sex, reproductive status, age, recent experiences) and ecological factors (e.g. predation, food availability, snowfall) can, by themselves or through their interactions with anthropogenic disturbances, affect the physiological stress response and mask any general patterns about the effects of anthropogenic disturbances on glucocorticoids. Using a meta-analysis, we show that anthropogenic disturbances are consistently associated with increased glucocorticoids regardless of the type of human disturbance. We also show that males may be more sensitive to anthropogenic disturbances than females and that faecal glucocorticoids, but not baseline plasma glucocorticoids, consistently increase in response to anthropogenic disturbances. Finally, we discuss how increases in glucocorticoids in free-living animals can sometimes enhance survival and reproduction. Unfortunately, our literature analysis indicates that this observation has not yet gained traction, and very few studies have shown that increases in glucocorticoid levels resulting from anthropogenic disturbances decrease survival or reproduction. We think that the use of measures of glucocorticoids in conservation physiology has tremendous potential, but there are still a number of methodological concerns, in addition to several crucial questions that should be addressed.
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Affiliation(s)
- Ben Dantzer
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Quinn E. Fletcher
- Département de biologie, chimie et geographie, Université du Québec á Rimouski, Rimouski, QC, Canada G5L 3A1
| | - Rudy Boonstra
- Centre for the Neurobiology of Stress, University of Toronto Scarborough, Toronto, ON, Canada M1C 1A4
| | - Michael J. Sheriff
- Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA 16801, USA
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267
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Woodley SK, Freeman P, Ricciardella LF. Environmental acidification is not associated with altered plasma corticosterone levels in the stream-side salamander, Desmognathus ochrophaeus. Gen Comp Endocrinol 2014; 201:8-15. [PMID: 24681152 DOI: 10.1016/j.ygcen.2014.03.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 01/29/2023]
Abstract
As environments become increasingly altered due to anthropogenic factors, interest is growing in how endocrine systems respond to pollution and environmental degradation. Glucocorticoid hormones (GCs) are a type of stress hormones that are released upon activation of the hypothalamic-pituitary-adrenal axis and have widespread effects throughout the body. We tested the hypothesis that exposure to environmental acidification is associated with altered levels of plasma GCs in adult, stream-side Allegheny Mountain dusky salamanders (Desmognathus ochrophaeus). We compared plasma corticosterone (CORT) in salamanders living in 9 streams that differed in pH. Although capture and handling induced a robust increase in plasma CORT in all populations of salamanders, we discerned no significant effect of environmental pH on baseline CORT or handling-induced CORT levels. In a laboratory study, low pH decreased salamander locomotory activity compared to acid-neutral controls, but there was no effect of pH on plasma CORT. Decreased locomotory activity is a common amphibian response to stress, indicating that low pH has adverse effects on Allegheny Mountain dusky salamanders. Overall, we conclude that the effects of environmental pH on salamander behavior and other potential responses are not mediated by changes in plasma CORT levels. We discuss alternative explanations for our results and describe difficulties involved in searching for relationships between plasma GCs and environmental degradation.
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Affiliation(s)
- Sarah K Woodley
- Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, USA.
| | - Peter Freeman
- Department of Statistics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Lauren F Ricciardella
- Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, USA
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268
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Mackay M, Rymer TL, Pillay N. Separation at weaning from the family is stressful for naturally group-living, but not solitary-living, male African striped mice Rhabdomys. Stress 2014; 17:266-74. [PMID: 24689755 DOI: 10.3109/10253890.2014.910762] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Early separation from a family is stressful for young mammals, but might be more stressful for group-living than solitary species. Using juvenile males of three African striped mice Rhabdomys taxa that are either group (R. pumilio) or solitary (R. dilectus dilectus and R. d. chakae) living, we predicted greater separation anxiety in R. pumilio than R. dilectus because group-living could reduce anxiety in R. pumilio. Three brothers from each of 10 litters per taxon were randomly assigned soon after natural weaning (25 days) to one of three treatments for 10 days: (1) remained with the family (philopatric); (2) separated from the family by a wire mesh barrier (separated); and (3) isolated from the family (isolated). Males were individually tested in a four-arm maze to assess their anxiety responses and sampled for corticosterone concentrations 20 mins and 10 days later. Compared to R. dilectus males, R. pumilio males showed a greater treatment response to separation: philopatric males used the light arms of the maze less and had higher corticosterone concentrations compared to isolated males, which spent the most time in the light arms and had the lowest corticosterone concentrations overall; separated males showed an intermediate behavioural response, but had similar corticosterone concentrations to philopatric males. Thus, separation from a family group is more stressful in group-living Rhabdomys and this stress response dissipates with time. Philopatry and group-living may be more important for young R. pumilio, whereas dispersal at weaning is an important life history event for solitary R. dilectus.
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Affiliation(s)
- Megan Mackay
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg , Wits , South Africa and
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269
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Aydinonat D, Penn DJ, Smith S, Moodley Y, Hoelzl F, Knauer F, Schwarzenberger F. Social isolation shortens telomeres in African Grey parrots (Psittacus erithacus erithacus). PLoS One 2014; 9:e93839. [PMID: 24705445 PMCID: PMC3976323 DOI: 10.1371/journal.pone.0093839] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 03/07/2014] [Indexed: 01/09/2023] Open
Abstract
Telomeres, the caps of eukaryotic chromosomes, control chromosome stability and cellular senescence, but aging and exposure to chronic stress are suspected to cause attrition of telomere length. We investigated the effect of social isolation on telomere length in the highly social and intelligent African Grey parrot (Psittacus erithacus erithacus). Our study population consisted of single-housed (n = 26) and pair-housed (n = 19) captive individuals between 0.75 to 45 years of age. Relative telomere length of erythrocyte DNA was measured by quantitative real-time PCR. We found that telomere length declined with age (p<0.001), and socially isolated parrots had significantly shorter telomeres compared to pair-housed birds (p<0.001) - even among birds of similar ages. Our findings provide the first evidence that social isolation affects telomere length, which supports the hypothesis that telomeres provide a biomarker indicating exposure to chronic stress.
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Affiliation(s)
- Denise Aydinonat
- Department of Biomedical Sciences, Biochemistry, University of Veterinary Medicine, Vienna, Austria
- Department of Integrative Biology and Evolution, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
| | - Dustin J. Penn
- Department of Integrative Biology and Evolution, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
- * E-mail:
| | - Steve Smith
- Department of Integrative Biology and Evolution, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
| | - Yoshan Moodley
- Department of Integrative Biology and Evolution, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
| | - Franz Hoelzl
- Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Felix Knauer
- Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Austria
| | - Franz Schwarzenberger
- Department of Biomedical Sciences, Biochemistry, University of Veterinary Medicine, Vienna, Austria
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270
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Sopinka NM, Hinch SG, Middleton CT, Hills JA, Patterson DA. Mother knows best, even when stressed? Effects of maternal exposure to a stressor on offspring performance at different life stages in a wild semelparous fish. Oecologia 2014; 175:493-500. [PMID: 24619199 DOI: 10.1007/s00442-014-2915-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 02/25/2014] [Indexed: 11/26/2022]
Abstract
The environment mothers are exposed to has resonating effects on offspring performance. In iteroparous species, maternal exposure to stressors generally results in offspring ill-equipped for survival. Still, opportunities for future fecundity can offset low quality offspring. Little is known, however, as to how intergenerational effects of stress manifest in semelparous species with only a single breeding episode. Such mothers would suffer a total loss of fitness if offspring cannot survive past multiple life stages. We evaluated whether chronic exposure of female sockeye salmon (Oncorhynchus nerka) to a chase stressor impaired offspring performance traits. Egg size and early offspring survival were not influenced by maternal exposure to the repeated acute stressor. Later in development, fry reared from stressed mothers swam for shorter periods of time but possessed a superior capacity to re-initiate bouts of burst swimming. In contrast to iteroparous species, the mechanisms driving the observed effects do not appear to be related to cortisol, as egg hormone concentrations did not vary between stressed and undisturbed mothers. Sockeye salmon appear to possess buffering strategies that protect offspring from deleterious effects of maternal stress that would otherwise compromise progeny during highly vulnerable stages of development. Whether stressed sockeye salmon mothers endow offspring with traits that are matched or mismatched for survival in the unpredictable environment they encountered is discussed. This study highlights the importance of examining intergenerational effects among species-specific reproductive strategies, and across offspring life history to fully determine the scope of impact of maternal stress.
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Affiliation(s)
- N M Sopinka
- Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada,
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271
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Hämäläinen A, Heistermann M, Fenosoa ZSE, Kraus C. Evaluating capture stress in wild gray mouse lemurs via repeated fecal sampling: method validation and the influence of prior experience and handling protocols on stress responses. Gen Comp Endocrinol 2014; 195:68-79. [PMID: 24212051 DOI: 10.1016/j.ygcen.2013.10.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 10/17/2013] [Accepted: 10/21/2013] [Indexed: 01/29/2023]
Abstract
Reliable measurements of physiological stress are increasingly needed for eco-physiological research and for species conservation or management. Stress can be estimated by quantifying plasma glucocorticoid levels, but when this is not feasible, glucocorticoid metabolites are often measured from feces (FGCM). However, evidence is accumulating on the sensitivity of FGCM measurements to various nuisance factors. Careful species- and context-specific validations are therefore necessary to confirm the biological relevance and specificity of the method. The goals of this study were to: (1) establish and validate sampling methods and an enzymeimmunoassay to measure FGCM in the gray mouse lemur (Microcebus murinus); (2) explore causes of variability in the FGCM measurements, and; (3) assess the consequences of capturing and handling for free-living individuals by quantifying their stress responses via repeated fecal sampling within capture sessions. We further assessed the influence of different handling protocols and the animals' previous capture experience on the magnitude of the physiological response. Our validations identified the group-specific measurement of 11ß-hydroxyetiocholanolone as the most suitable assay for monitoring adrenocortical activity. The sample water content and the animal's age were found to significantly influence baseline FGCM-levels. Most captured animals exhibited a post-capture FGCM-elevation but its magnitude was not related to the handling protocol or capture experience. We found no evidence for long-term consequences of routine capturing on the animals' stress physiology. Hence the described methods can be employed to measure physiological stress in mouse lemurs in an effective and relatively non-invasive way.
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Affiliation(s)
- Anni Hämäläinen
- Department of Sociobiology/Anthropology, University of Göttingen, Kellnerweg 6, 37077 Göttingen, Germany; Behavioral Ecology and Sociobiology Unit, German Primate Center DPZ, Kellnerweg 4, 37077 Göttingen, Germany.
| | - Michael Heistermann
- Endocrinology Laboratory, German Primate Center DPZ, Kellnerweg 4, 37077 Göttingen, Germany.
| | - Zo Samuel Ella Fenosoa
- Department of Animal Biology, Faculty of Sciences, University of Antananarivo, BP 906, Antananarivo 101, Madagascar.
| | - Cornelia Kraus
- Department of Sociobiology/Anthropology, University of Göttingen, Kellnerweg 6, 37077 Göttingen, Germany; Behavioral Ecology and Sociobiology Unit, German Primate Center DPZ, Kellnerweg 4, 37077 Göttingen, Germany; Courant Research Centre Evolution of Social Behaviour, Kellnerweg 6, 37077 Göttingen, Germany.
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272
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Lattin CR, Romero LM. Chronic stress alters concentrations of corticosterone receptors in a tissue-specific manner in wild house sparrows (Passer domesticus). J Exp Biol 2014; 217:2601-8. [DOI: 10.1242/jeb.103788] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Abstract
The physiological stress response results in release of glucocorticoid hormones such as corticosterone (CORT). Whereas short-term activation of this response helps animals cope with environmental stressors, chronic activation can result in negative effects including metabolic dysregulation and reproductive failure. However, there is no consensus hormonal profile of a chronically-stressed animal, suggesting researchers may need to look beyond hormone titers to interpret the impacts of chronic stress. In this study, we brought wild house sparrows (Passer domesticus) into captivity. We then compared glucocorticoid and mineralocorticoid receptor concentrations in sparrows exposed either to a standardized chronic stress protocol (n=26) or to standard husbandry conditions (controls; n=20). We used radioligand binding assays to quantify receptors in whole brain, liver, kidneys, spleen, gonads, gastrocnemius and pectoralis muscle, omental and subcutaneous fat, and bib and back skin. In most tissues, CORT receptors did not differ between controls and stressed animals, although we found marginal increases in receptor density in kidney and testis in stressed birds at some time points. Only in pectoralis muscle was there a robust effect of chronic stress, with both receptor types higher in stressed animals. Increased pectoralis sensitivity to CORT with chronic stress may be part of the underlying mechanism for muscle wasting in animals administered exogenous CORT. Furthermore, the change in pectoralis was not paralleled by gastrocnemius receptors. This difference may help explain previous reports of a greater effect of CORT on pectoralis than on other muscle types, and indicate that birds use this muscle as a protein reserve.
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273
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Leshyk R, Nol E, Chin EH, Burness G. Adult Ovenbirds (Seiurus aurocapilla) show increased stress-responsiveness in logged forests. Gen Comp Endocrinol 2013; 194:295-9. [PMID: 24140427 DOI: 10.1016/j.ygcen.2013.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 09/22/2013] [Accepted: 10/05/2013] [Indexed: 12/29/2022]
Abstract
Forest harvesting is a form of anthropogenic disturbance, yet the effects of such disturbance on the endocrine physiology of wildlife have been infrequently studied. We investigated the effect of two methods of forest harvesting ('intensive' and 'typical' group-selection silviculture) and un-harvested control sites on the glucocorticoid levels of adult Ovenbirds (Seiurus aurocapilla), a forest interior bird species. We collected blood samples from adult males immediately after capture to examine baseline corticosterone, and then following a standardized capture and restraint protocol, to examine stress-induced levels. There was no significant repeatability in either baseline or stress-induced corticosterone levels for eleven individuals measured in both years of study. Despite no differences across harvesting treatments in male body mass or baseline corticosterone levels, males captured in sites subjected to intensive harvesting had significantly higher stress-induced corticosterone levels than males in other treatments. Currently, the mechanism driving differences in stress-reactivity is unknown although we hypothesize that the size of gaps resulting from intensive group-selection silviculture may increase perceived predation risk. In comparison to our previous work on nestling Ovenbirds, adults respond differently to stress from group-selection silviculture.
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Affiliation(s)
- Rhiannon Leshyk
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada.
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274
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Fredebaugh-Siller S, Suski C, Zuckerman Z, Schooley R. Ecological correlates of stress for a habitat generalist in a biofuels landscape. CAN J ZOOL 2013. [DOI: 10.1139/cjz-2013-0157] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Understanding the success of habitat generalist species requires knowledge of how individuals respond to stressors that vary across habitats within landscapes. Habitat structure can affect stress by altering predation risk, conspecific densities, and densities of heterospecific competitors. Increased demand for biofuels will alter habitat structure for species in agroecosystems worldwide. We measured stress responses of deer mice (Peromyscus maniculatus (Wagner, 1845)), a widespread habitat generalist, in a biofuels landscape. We quantified fecal corticosterone concentrations for individuals in four biofuel crops: switchgrass (Panicum virgatum L.), miscanthus (Miscanthus × giganteus Greef & Deuter ex Hodkinson & Renvoize), mixed prairie, and corn (Zea mays L.). We also evaluated stress responses of deer mice to the annual harvesting of corn. Deer mice inhabiting switchgrass and mixed prairie had higher fecal corticosterone concentrations compared with mice in corn and miscanthus. Fecal corticosterone concentrations correlated positively with abundances of conspecifics and behaviorally dominant voles (prairie vole, Microtus ochrogaster (Wagner, 1842); meadow vole, Microtus pennsylvanicus (Ord, 1815)) across habitats. Stress levels of deer mice depended on how habitat structure modified the competitive environment. Deer mice did not exhibit increased fecal corticosterone concentrations in response to corn harvest, a rapid and extensive habitat disturbance common to agroecosystems. Our research is the first to investigate how landscape change due to biofuels expansion can affect stress levels of individuals.
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Affiliation(s)
- S.L. Fredebaugh-Siller
- Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
| | - C.D. Suski
- Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Z.C. Zuckerman
- Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
| | - R.L. Schooley
- Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 South Goodwin Avenue, Urbana, IL 61801, USA
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