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Ganz TR, Bassing SB, DeVivo MT, Gardner B, Kertson BN, Satterfield LC, Shipley LA, Turnock BY, Walker SL, Abrahamson D, Wirsing AJ, Prugh LR. White-tailed deer population dynamics in a multipredator landscape shaped by humans. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e3003. [PMID: 38890813 DOI: 10.1002/eap.3003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 02/23/2024] [Accepted: 04/22/2024] [Indexed: 06/20/2024]
Abstract
Large terrestrial mammals increasingly rely on human-modified landscapes as anthropogenic footprints expand. Land management activities such as timber harvest, agriculture, and roads can influence prey population dynamics by altering forage resources and predation risk via changes in habitat, but these effects are not well understood in regions with diverse and changing predator guilds. In northeastern Washington state, USA, white-tailed deer (Odocoileus virginianus) are vulnerable to multiple carnivores, including recently returned gray wolves (Canis lupus), within a highly human-modified landscape. To understand the factors governing predator-prey dynamics in a human context, we radio-collared 280 white-tailed deer, 33 bobcats (Lynx rufus), 50 cougars (Puma concolor), 28 coyotes (C. latrans), and 14 wolves between 2016 and 2021. We first estimated deer vital rates and used a stage-structured matrix model to estimate their population growth rate. During the study, we observed a stable to declining deer population (lambda = 0.97, 95% confidence interval: 0.88, 1.05), with 74% of Monte Carlo simulations indicating population decrease and 26% of simulations indicating population increase. We then fit Cox proportional hazard models to evaluate how predator exposure, use of human-modified landscapes, and winter severity influenced deer survival and used these relationships to evaluate impacts on overall population growth. We found that the population growth rate was dually influenced by a negative direct effect of apex predators and a positive effect of timber harvest and agricultural areas. Cougars had a stronger effect on deer population dynamics than wolves, and mesopredators had little influence on the deer population growth rate. Areas of recent timber harvest had 55% more forage biomass than older forests, but horizontal visibility did not differ, suggesting that timber harvest did not influence predation risk. Although proximity to roads did not affect the overall population growth rate, vehicle collisions caused a substantial proportion of deer mortalities, and reducing these collisions could be a win-win for deer and humans. The influence of apex predators and forage indicates a dual limitation by top-down and bottom-up factors in this highly human-modified system, suggesting that a reduction in apex predators would intensify density-dependent regulation of the deer population owing to limited forage availability.
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Affiliation(s)
- Taylor R Ganz
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Sarah B Bassing
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Melia T DeVivo
- Washington Department of Fish and Wildlife, Spokane Valley, Washington, USA
| | - Beth Gardner
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Brian N Kertson
- Washington Department of Fish and Wildlife, Snoqualmie, Washington, USA
| | - Lauren C Satterfield
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Lisa A Shipley
- School of the Environment, Washington State University, Pullman, Washington, USA
| | | | | | | | - Aaron J Wirsing
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Laura R Prugh
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
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Denryter K, Stephenson TR, Monteith KL. Migratory behaviours are risk-sensitive to physiological state in an elevational migrant. CONSERVATION PHYSIOLOGY 2024; 12:coae029. [PMID: 38779433 PMCID: PMC11109817 DOI: 10.1093/conphys/coae029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 04/17/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024]
Abstract
Accretion of body fat by animals is an important physiological adaptation that may underpin seasonal behaviours, especially where it modulates risk associated with a particular behaviour. Using movement data from male Sierra Nevada bighorn sheep (Ovis canadensis sierrae), we tested the hypothesis that migratory behaviours were risk-sensitive to physiological state (indexed by body fat). Sierra bighorn face severe winter conditions at high elevations and higher predation risk at lower elevations. Given that large body fat stores ameliorate starvation risk, we predicted that having small body fat stores would force animals to migrate to lower elevations with more abundant food supplies. We also predicted that body fat stores would influence how far animals migrate, with the skinniest animals migrating the furthest down in elevation (to access the most abundant food supplies at that time of year). Lastly, we predicted that population-level rates of switching between migratory tactics would be inversely related to body fat levels because as body fat levels decrease, animals exhibiting migratory plasticity should modulate their risk of starvation by switching migratory tactics. Consistent with our predictions, probability of migration and elevational distance migrated increased with decreasing body fat, but effects differed amongst metapopulations. Population-level switching rates also were inversely related to population-level measures of body fat prior to migration. Collectively, our findings suggest migration was risk-sensitive to physiological state, and failure to accrete adequate fat may force animals to make trade-offs between starvation and predation risk. In complex seasonal environments, risk-sensitive migration yields a layer of flexibility that should aid long-term persistence of animals that can best modulate their risk by attuning behaviour to physiological state.
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Affiliation(s)
- Kristin Denryter
- Haub School of Environment and Natural Resources, University of Wyoming, Bim Kendall House 804 E Fremont St, Laramie, WY 82072, USA
| | - Thomas R. Stephenson
- California Department of Fish and Wildlife, Sierra Nevada Bighorn Sheep Recovery Program, 787 N Main St., Bishop, CA 93514, USA
| | - Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Bim Kendall House 804 E Fremont St, Laramie, WY 82072, USA
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3
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Newediuk L, Mastromonaco GF, Vander Wal E. Associations between glucocorticoids and habitat selection reflect daily and seasonal energy requirements. MOVEMENT ECOLOGY 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] [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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Bates‐Mundell L, Williams SH, Sager‐Fradkin K, Wittmer HU, Allen ML, Cristescu B, Wilmers CC, Elbroch LM. Season, prey availability, sex, and age explain prey size selection in a large solitary carnivore. Ecol Evol 2024; 14:e11080. [PMID: 38455146 PMCID: PMC10918706 DOI: 10.1002/ece3.11080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/01/2024] [Accepted: 02/12/2024] [Indexed: 03/09/2024] Open
Abstract
Prey selection is a fundamental aspect of ecology that drives evolution and community structure, yet the impact of intraspecific variation on the selection for prey size remains largely unaccounted for in ecological theory. Here, we explored puma (Puma concolor) prey selection across six study sites in North and South America. Our results highlighted the strong influence of season and prey availability on puma prey selection, and the smaller influence of puma age. Pumas in all sites selected smaller prey in warmer seasons following the ungulate birth pulse. Our top models included interaction terms between sex and age, suggesting that males more than females select larger prey as they age, which may reflect experiential learning. When accounting for variable sampling across pumas in our six sites, male and female pumas killed prey of equivalent size, even though males are larger than females, challenging assumptions about this species. Nevertheless, pumas in different study sites selected prey of different sizes, emphasizing that the optimal prey size for pumas is likely context-dependent and affected by prey availability. The mean prey weight across all sites averaged 1.18 times mean puma weight, which was less than predicted as the optimal prey size by energetics and ecological theory (optimal prey = 1.45 puma weight). Our results help refine our understanding of optimal prey for pumas and other solitary carnivores, as well as corroborate recent research emphasizing that carnivore prey selection is impacted not just by energetics but by the effects of diverse ecology.
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Affiliation(s)
- Logan Bates‐Mundell
- Faculty of Environment and Natural ResourcesUniversity of FreiburgFreiburg im BreisgauGermany
| | | | - Kim Sager‐Fradkin
- Lower Elwha Klallam Tribe Natural ResourcesPort AngelesWashingtonUSA
| | - Heiko U. Wittmer
- School of Biological SciencesVictoria University of WellingtonWellingtonNew Zealand
| | - Maximilian L. Allen
- Illinois Natural History Survey, Prairie Research InstituteUniversity of IllinoisChampaignIllinoisUSA
| | - Bogdan Cristescu
- Environmental Studies DepartmentUniversity of CaliforniaSanta CruzCaliforniaUSA
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Williams S, Hebblewhite M, Martin H, Meyer C, Whittington J, Killeen J, Berg J, MacAulay K, Smolko P, Merrill EH. Predation risk drives long-term shifts in migratory behaviour and demography in a large herbivore population. J Anim Ecol 2024; 93:21-35. [PMID: 37982331 DOI: 10.1111/1365-2656.14022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 09/27/2023] [Indexed: 11/21/2023]
Abstract
Migration is an adaptive life-history strategy across taxa that helps individuals maximise fitness by obtaining forage and avoiding predation risk. The mechanisms driving migratory changes are poorly understood, and links between migratory behaviour, space use, and demographic consequences are rare. Here, we use a nearly 20-year record of individual-based monitoring of a large herbivore, elk (Cervus canadensis) to test hypotheses for changing patterns of migration in and adjacent to a large protected area in Banff National Park (BNP), Canada. We test whether bottom-up (forage quality) or top-down (predation risk) factors explained trends in (i) the proportion of individuals using 5 different migratory tactics, (ii) differences in survival rates of migratory tactics during migration and whilst on summer ranges, (iii) cause-specific mortality by wolves and grizzly bears, and (iv) population abundance. We found dramatic shifts in migration consistent with behavioural plasticity in individual choice of annual migratory routes. Shifts were inconsistent with exposure to the bottom-up benefits of migration. Instead, exposure to landscape gradients in predation risk caused by exploitation outside the protected area drove migratory shifts. Carnivore exploitation outside the protected area led to higher survival rates for female elk remaining resident or migrating outside the protected area. Cause-specific mortality aligned with exposure to predation risk along migratory routes and summer ranges. Wolf predation risk was higher on migratory routes than summer ranges of montane-migrant tactics, but wolf predation risk traded-off with heightened risk from grizzly bears on summer ranges. A novel eastern migrant tactic emerged following a large forest fire that enhanced forage in an area with lower predation risk outside of the protected area. The changes in migratory behaviour translated to population abundance, where abundance of the montane-migratory tactics declined over time. The presence of diverse migratory life histories maintained a higher total population abundance than would have been the case with only one migratory tactic in the population. Our study demonstrates the complex ways in which migratory populations change over time through behavioural plasticity and associated demographic consequences because of individuals balancing predation risk and forage trade-offs.
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Affiliation(s)
- S Williams
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, USA
| | - M Hebblewhite
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, USA
| | - H Martin
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, USA
| | - C Meyer
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, USA
| | - J Whittington
- Banff National Park, Parks Canada, Banff, Alberta, Canada
| | - J Killeen
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - J Berg
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - K MacAulay
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - P Smolko
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Department of Applied Zoology and Wildlife Management, Technical University in Zvolen, Zvolen, Slovakia
| | - E H Merrill
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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6
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Cirino LA. Seasonal shift in diet affects female reproductive anatomy but not mating behavior. Oecologia 2023:10.1007/s00442-023-05398-7. [PMID: 37354252 DOI: 10.1007/s00442-023-05398-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/31/2023] [Indexed: 06/26/2023]
Abstract
Females experience considerable environmental variability when breeding seasons are long. Adverse nutritional conditions can result in a reduction in mating and reproduction. However, a return to good nutrition may help animals resume high reproductive investment. I tested the silver spoon hypothesis in which females raised under poor conditions are reproductively limited compared to those raised under good conditions regardless of their adult environment. I used a specialist herbivore, Narnia femorata (Hemiptera: Coreidae), that lives on seasonally changing cacti. I provided juveniles and adults with a cactus pad with fruit (good diet), without fruit (restricted diet), or an improved adult diet (no fruit as juveniles, fruit at adulthood) to simulate a seasonal change in their diets near the end of the breeding season. I found that both ovary size and egg presence were reduced for females fed the restricted diet compared to those fed the good diet. Females fed the improved diet grew large ovaries like those fed the good diet, but few produced any eggs. Interestingly, female mating behavior did not change but females were less attractive to males when fed restricted diets. My results support the silver spoon hypothesis for compensatory growth and suggest that tradeoffs may occur between early survival and future reproduction when females experience a poor early life diet.
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Affiliation(s)
- Lauren A Cirino
- Entomology & Nematology Department, University of Florida, Gainesville, FL, 32611, USA.
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Lapham Hall, 3209 N Maryland Ave, Milwaukee, WI, 53211, USA.
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7
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Struck M, Severud WJ, Chenaux-Ibrahim YM, J. Isaac E, Brown JL, Moore SA, Wolf TM. Refining the moose serum progesterone threshold to diagnose pregnancy. CONSERVATION PHYSIOLOGY 2023; 11:coad003. [PMID: 38026802 PMCID: PMC10660365 DOI: 10.1093/conphys/coad003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 11/25/2022] [Accepted: 01/25/2023] [Indexed: 12/01/2023]
Abstract
Pregnancy determination is necessary for sound wildlife management and understanding population dynamics. Pregnancy rates are sensitive to environmental and physiological factors and may indicate the overall trajectory of a population. Pregnancy can be assessed through direct methods (rectal palpation, sonography) or indicated using hormonal assays (serum progesterone or pregnancy-specific protein B, fecal progestogen metabolites). A commonly used threshold of 2 ng/ml of progesterone in serum has been used by moose biologists to indicate pregnancy but has not been rigorously investigated. To refine this threshold, we examined the relationship between progesterone concentrations in serum samples and pregnancy in 87 moose (Alces alces; 64 female, 23 male) captured from 2010 to 2020 in the Grand Portage Indian Reservation in northeastern Minnesota, USA. Pregnancy was confirmed via rectal palpation (n = 25), necropsy (n = 2), calf observation (n = 25) or characteristic pre-calving behavior (n = 6), with a total of 58 females determined pregnant and 6 not pregnant; 23 males were included to increase the non-pregnant sample size. Using receiver operating characteristic analysis, we identified an optimal threshold of 1.115 ng/ml with a specificity of 0.97 (95% confidence interval [CI] = 0.90-1.00) and a sensitivity of 0.98 (95% CI = 0.95-1.00). Progesterone concentrations were significantly higher in cases of pregnant versus non-pregnant cows, but we did not detect a difference between single and twin births. We applied our newly refined threshold to calculate annual pregnancy rates for all female moose (n = 133) captured in Grand Portage from 2010 to 2021. Mean pregnancy rate during this period was 91% and ranged annually from 69.2 to 100%. Developing a reliable method for determining pregnancy status via serum progesterone analyses will allow wildlife managers to assess pregnancy rates of moose without devoting substantial time and resources to palpation and calf monitoring.
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Affiliation(s)
- Madeline Struck
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN 55108, USA
| | - William J Severud
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN 55108, USA
| | - Yvette M Chenaux-Ibrahim
- Department of Biology and Environment, Grand Portage Band of Lake Superior Chippewa, Grand Portage, MN 55605, USA
| | - Edmund J. Isaac
- Department of Biology and Environment, Grand Portage Band of Lake Superior Chippewa, Grand Portage, MN 55605, USA
| | - Janine L Brown
- Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Front Royal, VA, 22630, USA
| | - Seth A Moore
- Department of Biology and Environment, Grand Portage Band of Lake Superior Chippewa, Grand Portage, MN 55605, USA
| | - Tiffany M Wolf
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN 55108, USA
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8
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Walker RH, Hutchinson MC, Potter AB, Becker JA, Long RA, Pringle RM. Mechanisms of individual variation in large herbivore diets: Roles of spatial heterogeneity and state-dependent foraging. Ecology 2023; 104:e3921. [PMID: 36415899 PMCID: PMC10078531 DOI: 10.1002/ecy.3921] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/24/2022]
Abstract
Many populations of consumers consist of relatively specialized individuals that eat only a subset of the foods consumed by the population at large. Although the ecological significance of individual-level diet variation is recognized, such variation is difficult to document, and its underlying mechanisms are poorly understood. Optimal foraging theory provides a useful framework for predicting how individuals might select different diets, positing that animals balance the "opportunity cost" of stopping to eat an available food item against the cost of searching for something more nutritious; diet composition should be contingent on the distribution of food, and individual foragers should be more selective when they have greater energy reserves to invest in searching for high-quality foods. We tested these predicted mechanisms of individual niche differentiation by quantifying environmental (resource heterogeneity) and organismal (nutritional condition) determinants of diet in a widespread browsing antelope (bushbuck, Tragelaphus sylvaticus) in an African floodplain-savanna ecosystem. We quantified individuals' realized dietary niches (taxonomic richness and composition) using DNA metabarcoding of fecal samples collected repeatedly from 15 GPS-collared animals (range 6-14 samples per individual, median 12). Bushbuck diets were structured by spatial heterogeneity and constrained by individual condition. We observed significant individual-level partitioning of food plants by bushbuck both within and between two adjacent habitat types (floodplain and woodland). Individuals with home ranges that were closer together and/or had similar vegetation structure (measured using LiDAR) ate more similar diets, supporting the prediction that heterogeneous resource distribution promotes individual differentiation. Individuals in good nutritional condition had significantly narrower diets (fewer plant taxa), searched their home ranges more intensively (intensity-of-use index), and had higher-quality diets (percent digestible protein) than those in poor condition, supporting the prediction that animals with greater endogenous reserves have narrower realized niches because they can invest more time in searching for nutritious foods. Our results support predictions from optimal foraging theory about the energetic basis of individual-level dietary variation and provide a potentially generalizable framework for understanding how individuals' realized niche width is governed by animal behavior and physiology in heterogeneous landscapes.
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Affiliation(s)
- Reena H Walker
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
| | - Matthew C Hutchinson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Arjun B Potter
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Justine A Becker
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Ryan A Long
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
| | - Robert M Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
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Blum ME, Stewart KM, Cox M, Shoemaker KT, Bennett JR, Sullivan BW, Wakeling BF, Bleich VC. Variation in diet of desert bighorn sheep around parturition: Tradeoffs associated with parturition. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2022.1071771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Selection of forage and habitats is driven by nutritional needs of individuals. Some species may sacrifice nutritional quality of forage for the mother in favor of safety of offspring (risk-averse strategy), immediately following parturition. We studied diet quality and forage selection by bighorn sheep before and following parturition to determine how nutritional demands associated with rearing offspring influenced forage acquisition. We used desert bighorn sheep, Ovis canadensis nelsoni, to investigate that potential tradeoff. We captured and radio-collared female bighorn sheep from 2016 to 2018. We used vaginal implant transmitters (VIT)s in pregnant females to identify parturition and to capture and radio-collar neonates to monitor survival of young. We collected fecal samples throughout the breeding season and throughout the year to understand diet quality and composition throughout those temporal periods. We determined diet quality and composition for pre-parturient females, females provisioning offspring, females that lost offspring, and non-pregnant individuals using fecal nitrogen and DNA metabarcoding analyses. Additionally, we compared the diet quality and composition of offspring and adult females during the spring, as well as summer and winter months. Our results indicated differences in diet quality between individuals provisioning offspring and those whose offspring had died. Females that were provisioning dependent young had lower quality diets than those that lost their offspring. Diet composition among those groups was also markedly different; females that had lost an offspring had a more diverse diet than did females with dependent young. Diet quality differed among seasons, wherein offspring and adult females had higher quality diets during the spring months, with decreasing quality as the year progressed. Diet diversity was similar across seasons, although spring months tended to be most diverse. Our results support tradeoffs associated with risk-averse strategies made by adult females associated with parturition. Nutritional quality of forage was linked to provisioning status, indicating that females were trading diet quality for safety of offspring, but those females whose offspring had died selected high quality forages. Those results help explain habitat selection observed in mountain ungulates around parturition and provide further insight into the evolutionary processes and adaptive significance exhibited by those specialized artiodactyls.
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10
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Watkins BE, Bergman EJ, Dhaseleer LC, Bernal LJ. Factors influencing productivity and recruitment of elk in northern New Mexico. J Wildl Manage 2022. [DOI: 10.1002/jwmg.22348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Bruce E. Watkins
- Vermejo Park Ranch, Turner Enterprises, P.O. Drawer E, Raton NM 87740 USA
| | - Eric J. Bergman
- Colorado Parks and Wildlife, 317 Prospect Road Fort Collins CO 80526 USA
| | | | - Lance J. Bernal
- Vermejo Park Ranch, Turner Enterprises, P.O. Drawer E, Raton NM 87740 USA
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11
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Ranglack DH, Proffitt KM, Canfield JE, Gude JA, Rotella J, Garrott RA. Modeling broad‐scale patterns of elk summer resource selection in Montana using regional and population‐specific models. Ecosphere 2022. [DOI: 10.1002/ecs2.4311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Dustin H. Ranglack
- Fish and Wildlife Ecology and Management Program, Department of Ecology Montana State University Bozeman Montana USA
| | | | - Jodie E. Canfield
- Custer Gallatin National Forest, USDA Forest Service Bozeman Montana USA
| | | | - Jay Rotella
- Fish and Wildlife Ecology and Management Program, Department of Ecology Montana State University Bozeman Montana USA
| | - Robert A. Garrott
- Fish and Wildlife Ecology and Management Program, Department of Ecology Montana State University Bozeman Montana USA
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12
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McDonough TJ, Thompson DP, Crouse JA, Dale BW, Badajos OH. Evaluation of impacts of vaginal implant transmitter use in moose. WILDLIFE SOC B 2022. [DOI: 10.1002/wsb.1378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | - Daniel P. Thompson
- Alaska Department of Fish and Game, Kenai Moose Research Center 43961 Kalifornsky Beach Road Suite B Soldotna AK 99669 USA
| | - John A. Crouse
- Alaska Department of Fish and Game, Kenai Moose Research Center 43961 Kalifornsky Beach Road Suite B Soldotna AK 99669 USA
| | - Bruce W. Dale
- Alaska Department of Fish and Game 1800 Glenn Highway Suite 2 Palmer AK 99645 USA
| | - Oriana H. Badajos
- Alaska Department of Fish and Game 3298 Douglas Place, Homer AK 99603 USA
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13
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Links between individual performance, trace elements and stable isotopes in an endangered caribou population. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Schooler SL, Svoboda NJ, Finnegan SP, Crye J, Kellner KF, Belant JL. Maternal carryover, winter severity, and brown bear abundance relate to elk demographics. PLoS One 2022; 17:e0274359. [PMID: 36173937 PMCID: PMC9521920 DOI: 10.1371/journal.pone.0274359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 08/25/2022] [Indexed: 11/18/2022] Open
Abstract
Ungulates are key components of ecosystems due to their effects on lower trophic levels, role as prey, and value for recreational and subsistence harvests. Understanding factors that drive ungulate population dynamics can inform protection of important habitat and successful management of populations. To ascertain correlates of ungulate population dynamics, we evaluated the effects of five non-exclusive hypotheses on ungulate abundance and recruitment: winter severity, spring nutritional limitation (spring bottleneck), summer-autumn maternal condition carryover, predation, and timber harvest. We used weather, reconstructed brown bear (Ursus arctos) abundance, and timber harvest data to estimate support for these hypotheses on early calf recruitment (calves per 100 adult females in July–August) and population counts of Roosevelt elk (Cervus canadensis roosevelti) on Afognak and Raspberry islands, Alaska, USA, 1958–2020. Increasing winter temperatures positively affected elk abundance, supporting the winter severity hypothesis, while a later first fall freeze had a positive effect on elk recruitment, supporting the maternal carry-over hypothesis. Increased brown bear abundance was negatively associated with elk recruitment, supporting the predation hypothesis. Recruitment was unaffected by spring climate conditions or timber harvest. Severe winter weather likely increased elk energy deficits, reducing elk survival and subsequent abundance in the following year. Colder and shorter falls likely reduced late-season forage, resulting in poor maternal condition which limited elk recruitment more than winter severity or late-winter nutritional bottlenecks. Our results additionally demonstrated potential negative effects of brown bears on elk recruitment. The apparent long-term decline in elk recruitment did not result in a decline of abundance, which suggests that less severe winters may increase elk survival and counteract the potential effects of predation on elk abundance.
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Affiliation(s)
- Sarah L. Schooler
- Department of Environmental Biology, State University of New York College of Environmental Science and Forestry, Syracuse, New York, United States of America
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
| | - Nathan J. Svoboda
- Alaska Department of Fish and Game, Wildlife Division, Kodiak, Alaska, United States of America
| | - Shannon P. Finnegan
- Department of Environmental Biology, State University of New York College of Environmental Science and Forestry, Syracuse, New York, United States of America
| | - John Crye
- Alaska Department of Fish and Game, Wildlife Division, Kodiak, Alaska, United States of America
| | - Kenneth F. Kellner
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan, United States of America
| | - Jerrold L. Belant
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan, United States of America
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15
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Johnson HE, Lenart EA, Gustine DD, Adams LG, Barboza PS. Survival and reproduction in Arctic caribou are associated with summer forage and insect harassment. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.899585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Investigators have speculated that the climate-driven “greening of the Arctic” may benefit barren-ground caribou populations, but paradoxically many populations have declined in recent years. This pattern has raised concerns about the influence of summer habitat conditions on caribou demographic rates, and how populations may be impacted in the future. The short Arctic summer provides caribou with important forage resources but is also the time they are exposed to intense harassment by insects, factors which are both being altered by longer, warmer growing seasons. To better understand the effects of summer forage and insect activity on Arctic caribou demographic rates, we investigated the influence of estimated forage biomass, digestible energy (DE), digestible nitrogen (DN), and mosquito activity on the reproductive success and survival of adult females in the Central Arctic Herd on the North Slope of Alaska. We tested the hypotheses that greater early summer DN would increase subsequent reproduction (parturition and late June calving success) while greater biomass and DE would increase adult survival (September–May), and that elevated mosquito activity would reduce both demographic rates. Because the period when abundant forage DN is limited and overlaps with the period of mosquito harassment, we also expected years with low DN and high harassment to synergistically reduce caribou reproductive success. Examining these relationships at the individual-level, using GPS-collared females, and at the population-level, using long-term monitoring data, we generally found support for our expectations. Greater early summer DN was associated with increased subsequent calving success, while greater summer biomass was associated with increased adult survival. Mosquito activity was associated with reductions in adult female parturition, late June calving success, and survival, and in years with low DN, had compounding effects on subsequent late June calving success. Our findings indicate that summer nutrition and mosquito activity collectively influence the demographic rates of Arctic caribou, and may impact the dynamics of populations in the future under changing environmental conditions.
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16
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Cook RC, Shipley LA, Cook JG, Camp MJ, Monzingo DS, Robatcek SL, Berry SL, Hull IT, Myers WL, Denryter K, Long RA. Sequential detergent fiber assay results used for nutritional ecology research: Evidence of bias since 2012. WILDLIFE SOC B 2022. [DOI: 10.1002/wsb.1348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Rachel C. Cook
- National Council of Air and Stream Improvement 1401 Gekeler Lane La Grande OR 97850 USA
| | - Lisa A. Shipley
- 1229 Webster Hall, School of the Environment Washington State University Pullman WA 99164‐2812 USA
| | - John G. Cook
- National Council of Air and Stream Improvement 1401 Gekeler Lane La Grande OR 97850 USA
| | - Meghan J. Camp
- Washington State University Vogel Plant Biosciences 136, School of the Environment, Pullman, WA 99164‐2812; Cramer Fish Sciences 1125 12th Ave. NW, Suite B‐1 Issaquah WA 98027 USA
| | - Deborah S. Monzingo
- 1229 Webster Hall, School of the Environment Washington State University Pullman WA 99164‐2812 USA
| | | | | | - Iver T. Hull
- 1229 Webster Hall, School of the Environment Washington State University Pullman WA 99164‐2812 USA
| | - Woodrow L. Myers
- Washington Department of Fish and Wildlife 2315 N Discovery Place Spokane Valley WA 99216 USA
| | - Kristin Denryter
- California Department of Fish and Wildlife 1010 Riverside Parkway West Sacramento CA 95605 USA
| | - Ryan A. Long
- Department of Fish and Wildlife Sciences University of Idaho Moscow ID 83844 USA
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17
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Paterson JT, Proffitt KM, DeCesare NJ, Gude JA, Hebblewhite M. Evaluating the summer landscapes of predation risk and forage quality for elk ( Cervus canadensis). Ecol Evol 2022; 12:e9201. [PMID: 35979523 PMCID: PMC9366754 DOI: 10.1002/ece3.9201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/12/2022] [Accepted: 07/14/2022] [Indexed: 11/25/2022] Open
Abstract
The recovery of carnivore populations in North American has consequences for trophic interactions and population dynamics of prey. In addition to direct effects on prey populations through killing, predators can influence prey behavior by imposing the risk of predation. The mechanisms through which patterns of space use by predators are linked to behavioral response by prey and nonconsumptive effects on prey population dynamics are poorly understood. Our goal was to characterize population‐ and individual‐level patterns of resource selection by elk (Cervus canadensis) in response to risk of wolves (Canis lupus) and mountain lions (Puma concolor) and evaluate potential nonconsumptive effects of these behavioral patterns. We tested the hypothesis that individual elk risk‐avoidance behavior during summer would result in exposure to lower‐quality forage and reduced body fat and pregnancy rates. First, we evaluated individuals' second‐order and third‐order resource selection with a used‐available sampling design. At the population level, we found evidence for a positive relationship between second‐ and third‐order selection and forage, and an interaction between forage quality and mountain lion risk such that the relative probability of use at low mountain lion risk increased with forage quality but decreased at high risk at both orders of selection. We found no evidence of a population‐level trade‐off between forage quality and wolf risk. However, we found substantial among‐individual heterogeneity in resource selection patterns such that population‐level patterns were potentially misleading. We found no evidence that the diversity of individual resource selection patterns varied predictably with available resources, or that patterns of individual risk‐related resource selection translated into biologically meaningful changes in body fat or pregnancy rates. Our work highlights the importance of evaluating individual responses to predation risk and predator hunting technique when assessing responses to predators and suggests nonconsumptive effects are not operating at a population scale in this system.
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Affiliation(s)
| | | | | | | | - Mark Hebblewhite
- Department of Ecosystem and Conservation Sciences University of Montana Missoula Montana USA
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18
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Denryter K, Conner MM, Stephenson TR, German DW, Monteith KL. Survival of the fattest: how body fat and migration influence survival in highly seasonal environments. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Kristin Denryter
- Haub School of Environment and Natural Resources University of Wyoming, 804 East Fremont Laramie WY USA
| | - Mary M. Conner
- Utah State University Department of Wildland Resources, 5320 Old Main Hill Logan UT USA
- California Department of Fish and Wildlife, 787 North Main Street, Suite 220 Bishop CA USA
| | - Thomas R. Stephenson
- California Department of Fish and Wildlife, Sierra Nevada Bighorn Sheep Recovery Program, 787 North Main Street, Suite 220 Bishop CA USA
| | - David W. German
- California Department of Fish and Wildlife, Sierra Nevada Bighorn Sheep Recovery Program, 787 North Main Street, Suite 220 Bishop CA USA
| | - Kevin L. Monteith
- Haub School of Environment and Natural Resources Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, 804 East Fremont Laramie WY USA
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19
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Smiley RA, Wagler BL, LaSharr TN, Denryter KA, Stephenson TR, Courtemanch AB, Mong TW, Lutz D, McWhirter D, Brimeyer D, Hnilicka P, Lowrey B, Monteith KL. Heterogeneity in risk‐sensitive allocation of somatic reserves in a long‐lived mammal. Ecosphere 2022. [DOI: 10.1002/ecs2.4161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Rachel A. Smiley
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | - Brittany L. Wagler
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | - Tayler N. LaSharr
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | | | - Thomas R. Stephenson
- Sierra Nevada Bighorn Sheep Recovery Program, California Department of Fish and Wildlife Bishop California USA
| | | | - Tony W. Mong
- Wyoming Game and Fish Department Cody Wyoming USA
| | - Daryl Lutz
- Wyoming Game and Fish Department Lander Wyoming USA
| | | | - Doug Brimeyer
- Wyoming Game and Fish Department Cheyenne Wyoming USA
| | | | - Blake Lowrey
- Fish and Wildlife Ecology and Management Program, Department of Ecology Montana State University Bozeman Montana USA
| | - Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
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20
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Snobl LA, Proffitt KM, Millspaugh JJ. Wildfire extends the shelf life of elk nutritional resources regardless of fire severity. Ecosphere 2022. [DOI: 10.1002/ecs2.4178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Lauren A. Snobl
- Wildlife Biology Program University of Montana Missoula Montana USA
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21
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Hayes FP, Millspaugh JJ, Bergman EJ, Callaway RM, Bishop CJ. Effects of willow nutrition and morphology on calving success of moose. J Wildl Manage 2022. [DOI: 10.1002/jwmg.22175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Forest P. Hayes
- Wildlife Biology Program University of Montana Missoula, MT 59812 USA
| | | | | | - Ragan M. Callaway
- Wildlife Biology Program University of Montana Missoula, MT 59812 USA
| | - Chad J. Bishop
- Wildlife Biology Program University of Montana Missoula, MT 59812 USA
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22
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Denryter K, Cook RC, Cook JG, Parker KL. Animal‐defined resources reveal nutritional inadequacies for woodland caribou during summer–autumn. J Wildl Manage 2022. [DOI: 10.1002/jwmg.22161] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kristin Denryter
- Natural Resources and Environmental Studies University of Northern British Columbia 3333 University Way Prince George V2N 4Z9 BC Canada
| | - Rachel C. Cook
- National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory 1401 Gekeler Lane La Grande 97850 OR USA
| | - John G. Cook
- National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory 1401 Gekeler Lane La Grande 97850 OR USA
| | - Katherine L. Parker
- Natural Resources and Environmental Studies University of Northern British Columbia 3333 University Way Prince George V2N 4Z9 BC Canada
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23
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Woodruff SP, Andersen EM, Wilson RR, Mangipane LS, Miller SB, Klein KJ, Lemons PR. Classifying the effects of human disturbance on denning polar bears. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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24
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R. Hoy S, Forbey JS, Melody DP, Vucetich LM, Peterson RO, Koitzsch KB, Koitzsch LO, Von Duyke AL, Henderson JJ, Parikh GL, Vucetich JA. The nutritional condition of moose co‐varies with climate, but not with density, predation risk or diet composition. OIKOS 2021. [DOI: 10.1111/oik.08498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sarah R. Hoy
- College of Forest Resources and Environmental Science, Michigan Technological Univ. Houghton MI USA
| | | | | | - Leah M. Vucetich
- College of Forest Resources and Environmental Science, Michigan Technological Univ. Houghton MI USA
| | - Rolf O. Peterson
- College of Forest Resources and Environmental Science, Michigan Technological Univ. Houghton MI USA
| | - K. B. Koitzsch
- College of Forest Resources and Environmental Science, Michigan Technological Univ. Houghton MI USA
- K2 Consulting Waitsfield VT USA
| | - Lisa O. Koitzsch
- College of Forest Resources and Environmental Science, Michigan Technological Univ. Houghton MI USA
- K2 Consulting Waitsfield VT USA
| | | | - John J. Henderson
- College of Forest Resources and Environmental Science, Michigan Technological Univ. Houghton MI USA
| | - Grace L. Parikh
- College of Forest Resources and Environmental Science, Michigan Technological Univ. Houghton MI USA
| | - John A. Vucetich
- College of Forest Resources and Environmental Science, Michigan Technological Univ. Houghton MI USA
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25
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Cook JG, Kelly AP, Cook RC, Culling B, Culling D, McLaren A, Larter NC, Watters M. Seasonal patterns in nutritional condition of caribou (Rangifer tarandus) in the southern Northwest Territories and northeastern British Columbia, Canada. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2021-0057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Evaluating nutritional condition provides insights of nutritional influences on wildlife populations. We sampled three measures of condition — body fat, body mass, and loin thickness — of adult female caribou (Rangifer tarandus (Linnaeus, 1758)) in boreal settings in the Northwest Territories (NT), Canada, in December and March, 2016–2018, and in mountain and boreal settings in British Columbia (BC), Canada, in December and February, 2014–2015. We evaluated the effect of calf-rearing on condition in December, compared influences of summer–autumn versus winter on condition over winter, and developed an annual profile of nutritional condition with estimates from caribou dying in summer. Mean December body fat was 8.4% in females with calves and 11.4% in females without calves, demonstrating the influence of lactation on condition. Over winter, nutritional condition did not decline in northeastern BC and it declined slightly in NT: body fat by 0.55 percentage points, mass by 2.8 kg, and loin thickness did not change. Body fat peaked in December, changed little over winter, but declined to a minimum by early summer, temporally coinciding with elevated rates of adult female mortality. Consistent with those of other ungulate studies worldwide, our findings suggest a need to focus on nutritional limitations operating in late spring through early autumn.
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Affiliation(s)
- John G. Cook
- Forestry and Range Sciences Laboratory, National Council for Air and Stream Improvement, 1401 Gekeler Lane, La Grande, OR 1401 Gekeler Lane, USA
| | - Allicia P. Kelly
- Department of Environment and Natural Resources, Government of the Northwest Territories, Box 900, Fort Smith, NT X0E 0P0, Canada
| | - Rachel C. Cook
- Forestry and Range Sciences Laboratory, National Council for Air and Stream Improvement, 1401 Gekeler Lane, La Grande, OR 1401 Gekeler Lane, USA
| | - Brad Culling
- Diversified Environmental, Box 6263, Fort St. John, BC V1J 4X7, Canada
| | - Diane Culling
- Diversified Environmental, Box 6263, Fort St. John, BC V1J 4X7, Canada
| | - Ashley McLaren
- Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources and Forestry, Peterborough, ON K9L 1Z8, Canada
| | - Nicholas C. Larter
- Department of Environment and Natural Resources, Government of the Northwest Territories, Fort Simpson, NT X0E 0N0, Canada
| | - Megan Watters
- British Columbia Ministry of Forests, Lands, Natural Resource Operations and Rural Development, Fort St. John, BC V1J 6M7, Canada
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26
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Chirichella R, De Marinis AM, Pokorny B, Apollonio M. Dentition and body condition: tooth wear as a correlate of weight loss in roe deer. Front Zool 2021; 18:47. [PMID: 34544436 PMCID: PMC8454088 DOI: 10.1186/s12983-021-00433-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 09/07/2021] [Indexed: 12/05/2022] Open
Abstract
Background In many mammalian species, once the permanent teeth have erupted, the only change to dentition is a gradual loss of tooth surface/height through wear. The crown of the teeth cannot be repaired once worn. When dental crown tissue has been depleted due to wear, the animal is expected to have a suboptimal body condition. We evaluated the role of tooth wear in causing a reduction of physical condition in adult roe deer females (Capreolus capreolus). Results The progressive wearing of the lower cheek teeth was assessed in a Northern Apennines (Italy) population with a new scoring scheme based on objectively described tooth characteristics (morphotypes) being either present or absent. Eviscerated body mass and mandible length, which is a good proxy for body size in roe deer, were related to the tooth wear score by the use of linear regressions. The sum of wear scores for molariform teeth correlated most strongly with body condition (i.e., eviscerated body mass/mandible length), showing the importance of the entire chewing surface for acquiring energy by food comminution, chewing, and digestion. In comparison with individuals of comparable size experiencing minor tooth wear, the body mass of those with the most advanced stage of tooth wear was decreased by 33.7%. This method was compared to the height and the hypsodonty index of the first molar, the most commonly used indices of tooth wear. The sum of molariform wear scoring scheme resulted in a more suitable index to describe the variation in body condition of roe deer. Conclusions Describing tooth wear patterns in hunted populations and monitoring at which tooth wear level (and therefore dental morphotype) an animal is no longer able to sustain its physical condition (i.e. when it begins to lose body mass) can be a useful tool for improving the management of the most widespread and abundant deer species in Europe. At the same time, such an approach can clarify the role of tooth wear as a proximate cause of senescence in ungulates. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00433-w.
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Affiliation(s)
- Roberta Chirichella
- Department of Veterinary Medicine, University of Sassari, Via Vienna 2, 07100, Sassari, Italy.
| | - Anna Maria De Marinis
- Italian Institute for Environmental Protection and Research (ISPRA), Via Ca' Fornacetta 9, 40064, Ozzano dell'Emilia (BO), Italy
| | - Boštjan Pokorny
- Environmental Protection College, Trg mladosti 7, 3320, Velenje, Slovenia.,Slovenian Forestry Institute, Večna pot 2, 1000, Ljubljana, Slovenia
| | - Marco Apollonio
- Department of Veterinary Medicine, University of Sassari, Via Vienna 2, 07100, Sassari, Italy
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27
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Felton AM, Wam HK, Felton A, Simpson SJ, Stolter C, Hedwall P, Malmsten J, Eriksson T, Tigabo M, Raubenheimer D. Macronutrient balancing in free-ranging populations of moose. Ecol Evol 2021; 11:11223-11240. [PMID: 34429914 PMCID: PMC8366896 DOI: 10.1002/ece3.7909] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/22/2021] [Accepted: 06/28/2021] [Indexed: 11/28/2022] Open
Abstract
At northern latitudes, large spatial and temporal variation in the nutritional composition of available foods poses challenges to wild herbivores trying to satisfy their nutrient requirements. Studies conducted in mostly captive settings have shown that animals from a variety of taxonomic groups deal with this challenge by adjusting the amounts and proportions of available food combinations to achieve a target nutrient balance. In this study, we used proportions-based nutritional geometry to analyze the nutritional composition of rumen samples collected in winter from 481 moose (Alces alces) in southern Sweden and examine whether free-ranging moose show comparable patterns of nutrient balancing. Our main hypothesis was that wild moose actively regulate their rumen nutrient composition to offset ecologically imposed variation in the nutritional composition of available foods. To test this, we assessed the macronutritional composition (protein, carbohydrates, and lipids) of rumen contents and commonly eaten foods, including supplementary feed, across populations with contrasting winter diets, spanning an area of approximately 10,000 km2. Our results suggest that moose balanced the macronutrient composition of their rumen, with the rumen contents having consistently similar proportional relationship between protein and nonstructural carbohydrates, despite differences in available (and eaten) foods. Furthermore, we found that rumen macronutrient balance was tightly related to ingested levels of dietary fiber (cellulose and hemicellulose), such that the greater the fiber content, the less protein was present in the rumen compared with nonstructural carbohydrates. Our results also suggest that moose benefit from access to a greater variety of trees, shrubs, herbs, and grasses, which provides them with a larger nutritional space to maneuver within. Our findings provide novel theoretical insights into a model species for ungulate nutritional ecology, while also generating data of direct relevance to wildlife and forest management, such as silvicultural or supplementary feeding practices.
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Affiliation(s)
- Annika M. Felton
- Southern Swedish Forest Research CentreSwedish University of Agricultural SciencesAlnarpSweden
| | - Hilde K. Wam
- Division of Forestry and Forest ResourcesNIBIOÅsNorway
| | - Adam Felton
- Southern Swedish Forest Research CentreSwedish University of Agricultural SciencesAlnarpSweden
| | - Stephen J. Simpson
- Charles Perkins Centre, and School of Life and Environmental SciencesUniversity of SydneyCamperdownNSWAustralia
| | - Caroline Stolter
- Department of Animal Ecology and ConservationInstitute of ZoologyUniversity of HamburgHamburgGermany
| | - Per‐Ola Hedwall
- Southern Swedish Forest Research CentreSwedish University of Agricultural SciencesAlnarpSweden
| | - Jonas Malmsten
- Department of Wildlife, Fish and Environmental StudiesSwedish University of Agricultural Sciences (SLU)UmeåSweden
| | - Torsten Eriksson
- Department of Animal Nutrition and ManagementSwedish University of Agricultural SciencesUppsalaSweden
| | - Mulualem Tigabo
- Southern Swedish Forest Research CentreSwedish University of Agricultural SciencesAlnarpSweden
| | - David Raubenheimer
- Charles Perkins Centre, and School of Life and Environmental SciencesUniversity of SydneyCamperdownNSWAustralia
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28
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Cook RC, Crouse JA, Cook JG, Stephenson TR. Evaluating indices of nutritional condition for caribou (Rangifer tarandus): which are the most valuable and why? CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Body composition studies are critical for evaluating the accuracy of nutritional condition indices for predicting body components. We evaluated >40 indices of nutritional condition for caribou (Rangifer tarandus (Linnaeus, 1758)) using 29 female caribou captured from three populations in Alaska (USA) that ranged in condition from 2.3% to 11.2% ingesta-free body fat (IFBF) and 6 captive female caribou that ranged in condition from 8.1% to 26.0% IFBF. Estimates of body fat, protein, and gross energy were regressed against each index of nutritional condition. Generally, indices with linear or slightly curvilinear relations to body fat and those based on multiple fat depots were the most accurate in predicting nutritional condition and the most useful over the full range of nutritional condition. A scaledLIVINDEX (a combination of subcutaneous fat thickness and a condition score), CONINDEX (a combination of kidney fat and marrow fat), and a subset of the Kistner score (pericardium and kidneys only) had the strongest relationship with body fat (r2 > 0.86) and were useful over the entire range of nutritional condition. If used properly and with adequate training, indices of nutritional condition can be a critical tool for understanding the severity and seasonality of nutritional limitations in wild caribou populations.
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Affiliation(s)
- Rachel C. Cook
- National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory, 1401 Gekeler Lane, La Grande, OR 97850, USA
| | - John A. Crouse
- Kenai Moose Research Center, Alaska Department of Fish and Game, 43961 Kalifornsky Beach Road, Suite B, Soldotna, AK 99669, USA
| | - John G. Cook
- National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory, 1401 Gekeler Lane, La Grande, OR 97850, USA
| | - Thomas R. Stephenson
- Sierra Nevada Bighorn Sheep Recovery Program, California Department of Fish and Wildlife, 787 North Main Street, Suite 220, Bishop, CA 93514, USA
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Sergeyev M, McMillan BR, Hersey KR, Larsen RT. How Size and Condition Influence Survival and Cause‐Specific Mortality of Female Elk. J Wildl Manage 2021. [DOI: 10.1002/jwmg.22000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Maksim Sergeyev
- Department of Plant and Wildlife Sciences Brigham Young University Provo UT 84604 USA
| | - Brock R. McMillan
- Department of Plant and Wildlife Sciences Brigham Young University Provo UT 84604 USA
| | - Kent R. Hersey
- Utah Division of Wildlife Resources Salt Lake City UT 84116 USA
| | - Randy T. Larsen
- Department of Plant and Wildlife Sciences Brigham Young University Provo UT 84604 USA
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30
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Proffitt KM, Courtemanch AB, Dewey SR, Lowrey B, McWhirter DE, Monteith K, Paterson JT, Rotella J, White PJ, Garrott RA. Regional variability in pregnancy and survival rates of Rocky Mountain bighorn sheep. Ecosphere 2021. [DOI: 10.1002/ecs2.3410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Kelly M. Proffitt
- Montana Department of Fish Wildlife, and Parks 1400 South 19th Avenue Bozeman Montana59718USA
| | | | - Sarah R. Dewey
- Grand Teton National Park P.O. Box 170 Moose Wyoming83012USA
| | - Blake Lowrey
- Fish and Wildlife Ecology and Management Program Department of Ecology Montana State University 310 Lewis Hall Bozeman Montana59717USA
| | | | - Kevin.L. Monteith
- Haub School of Environment and Natural Resources Wyoming Cooperative Fish and Wildlife Research Unit Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie Wyoming82072USA
| | - J. Terrill Paterson
- Fish and Wildlife Ecology and Management Program Department of Ecology Montana State University 310 Lewis Hall Bozeman Montana59717USA
| | - Jay Rotella
- Fish and Wildlife Ecology and Management Program Department of Ecology Montana State University 310 Lewis Hall Bozeman Montana59717USA
| | - Patrick J. White
- Yellowstone Center for Resources Yellowstone National Park National Park Service Mammoth Wyoming82190USA
| | - Robert A. Garrott
- Fish and Wildlife Ecology and Management Program Department of Ecology Montana State University 310 Lewis Hall Bozeman Montana59717USA
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Oates BA, Monteith KL, Goheen JR, Merkle JA, Fralick GL, Kauffman MJ. Detecting Resource Limitation in a Large Herbivore Population Is Enhanced With Measures of Nutritional Condition. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.522174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Resource limitation at the population level is a function of forage quality and its abundance relative to its per capita availability, which in turn, determines nutritional condition of individuals. Effects of resource limitation on population dynamics in ungulates often occur through predictable and sequential changes in vital rates, which can enable assessments of how resource limitation influences population growth. We tested theoretical predictions of bottom-up (i.e., resource limitation) forcing on moose (Alces alces) through the lens of vital rates by quantifying the relative influence of intrinsic measures of nutritional condition and extrinsic measures of remotely sensed environmental data on demographic rates. We measured rates of pregnancy, parturition, juvenile, and adult survival for 82 adult females in a population where predators largely were absent. Life stage simulation analyses (LSAs) indicated that interannual fluctuations in adult survival contributed to most of the variability in λ. We then extended the LSA to estimate vital rates as a function of bottom-up covariates to evaluate their influence on λ. We detected weak signatures of effects from environmental covariates that were remotely sensed and spatially explicit to each seasonal range. Instead, nutritional condition strongly influenced rates of pregnancy, parturition, and overwinter survival of adults, clearly implicating resource limitation on λ. Our findings depart from the classic life-history paradigm of population dynamics in ungulates in that adult survival was highly variable and generated most of the variability in population growth rates. At the surface, lack of variation explained by environmental covariates may suggest weak evidence of resource limitation in the population, when nutritional condition actually underpinned most demographics. We suggest that variability in vital rates and effects of resource limitation may depend on context more than previously appreciated, and density dependence can obfuscate the relationships between remotely sensed data and demographic rates.
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Denryter K, German DW, Stephenson TR, Monteith KL. State- and context-dependent applications of an energetics model in free-ranging bighorn sheep. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2020.109349] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ortega AC, Dwinnell SP, Lasharr TN, Jakopak RP, Denryter K, Huggler KS, Hayes MM, Aikens EO, Verzuh TL, May AB, Kauffman MJ, Monteith KL. Effectiveness of Partial Sedation to Reduce Stress in Captured Mule Deer. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Anna C. Ortega
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 1000 East University Avenue Laramie WY 82072 USA
| | - Samantha P. Dwinnell
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
| | - Tayler N. Lasharr
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
| | - Rhiannon P. Jakopak
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
| | - Kristin Denryter
- Haub School of Environment and Natural Resources University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
| | - Katey S. Huggler
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
| | - Matthew M. Hayes
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
| | - Ellen O. Aikens
- Program in Ecology, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 1000 East University Avenue Laramie WY 82071 USA
| | - Tana L. Verzuh
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
| | - Alexander B. May
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
| | - Matthew J. Kauffman
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 1000 East University Avenue Laramie WY 82072 USA
| | - Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming 804 East Fremont Street Laramie WY 82072 USA
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Walker PD, Rodgers AR, Shuter JL, Thompson ID, Fryxell JM, Cook JG, Cook RC, Merrill EH. Comparison of Woodland Caribou Calving Areas Determined by Movement Patterns Across Northern Ontario. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21961] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Philip D. Walker
- Department of Biological Sciences University of Alberta Edmonton AB T6G 2E9 Canada
| | - Arthur R. Rodgers
- Ontario Ministry of Natural Resources and Forestry Centre for Northern Forest Ecosystem Research 103‐421 James Street South Thunder Bay ON P7E 2V6 Canada
| | - Jennifer L. Shuter
- Ontario Ministry of Natural Resources and Forestry Centre for Northern Forest Ecosystem Research 103‐421 James Street South Thunder Bay ON P7E 2V6 Canada
| | - Ian D. Thompson
- Canadian Forest Service (Retired) 1219 Queen Street E, Sault Ste. Marie ON P6A 2E5 Canada
| | - John M. Fryxell
- Department of Integrative Biology University of Guelph Guelph ON N1G 2W1 Canada
| | - John G. Cook
- National Council for Air and Stream Improvement Forestry and Range Science Laboratory 1401 Gekeler Lane La Grande OR 97850 USA
| | - Rachel C. Cook
- National Council for Air and Stream Improvement Forestry and Range Science Laboratory 1401 Gekeler Lane La Grande OR 97850 USA
| | - Eveyln H. Merrill
- Department of Biological Sciences University of Alberta Edmonton AB T6G 2E9 Canada
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Merrill E, Killeen J, Pettit J, Trottier M, Martin H, Berg J, Bohm H, Eggeman S, Hebblewhite M. Density-Dependent Foraging Behaviors on Sympatric Winter Ranges in a Partially Migratory Elk Population. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Stephenson TR, German DW, Cassirer EF, Walsh DP, Blum ME, Cox M, Stewart KM, Monteith KL. Linking population performance to nutritional condition in an alpine ungulate. J Mammal 2020; 101:1244-1256. [PMID: 33335453 PMCID: PMC7733374 DOI: 10.1093/jmammal/gyaa091] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 07/10/2020] [Indexed: 11/14/2022] Open
Abstract
Bighorn sheep (Ovis canadensis) can live in extremely harsh environments and subsist on submaintenance diets for much of the year. Under these conditions, energy stored as body fat serves as an essential reserve for supplementing dietary intake to meet metabolic demands of survival and reproduction. We developed equations to predict ingesta-free body fat in bighorn sheep using ultrasonography and condition scores in vivo and carcass measurements postmortem. We then used in vivo equations to investigate the relationships between body fat, pregnancy, overwinter survival, and population growth in free-ranging bighorn sheep in California and Nevada. Among 11 subpopulations that included alpine winter residents and migrants, mean ingesta-free body fat of lactating adult females during autumn ranged between 8.8% and 15.0%; mean body fat for nonlactating females ranged from 16.4% to 20.9%. In adult females, ingesta-free body fat > 7.7% during January (early in the second trimester) corresponded with a > 90% probability of pregnancy and ingesta-free body fat > 13.5% during autumn yielded a probability of overwinter survival > 90%. Mean ingesta-free body fat of lactating females in autumn was positively associated with finite rate of population increase (λ) over the subsequent year in bighorn sheep subpopulations that wintered in alpine landscapes. Bighorn sheep with ingesta-free body fat of 26% in autumn and living in alpine environments possess energy reserves sufficient to meet resting metabolism for 83 days on fat reserves alone. We demonstrated that nutritional condition can be a pervasive mechanism underlying demography in bighorn sheep and characterizes the nutritional value of their occupied ranges. Mountain sheep are capital survivors in addition to being capital breeders, and because they inhabit landscapes with extreme seasonal forage scarcity, they also can be fat reserve obligates. Quantifying nutritional condition is essential for understanding the quality of habitats, how it underpins demography, and the proximity of a population to a nutritional threshold.
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Affiliation(s)
- Thomas R Stephenson
- Sierra Nevada Bighorn Sheep Recovery Program, California Department of Fish and Wildlife, Bishop, CA, USA
| | - David W German
- Sierra Nevada Bighorn Sheep Recovery Program, California Department of Fish and Wildlife, Bishop, CA, USA
| | | | | | - Marcus E Blum
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV, USA
| | - Mike Cox
- Nevada Department of Wildlife, Reno, NV, USA
| | - Kelley M Stewart
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV, USA
| | - Kevin L Monteith
- Haub School of the Environment, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA (KLM)
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37
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Jones PF, Jakes AF, Eacker DR, Hebblewhite M. Annual Pronghorn Survival of a Partially Migratory Population. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21886] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Paul F. Jones
- Alberta Conservation Association Lethbridge AB T1J 0P6 Canada
| | - Andrew F. Jakes
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and ConservationUniversity of Montana Missoula MT 59812 USA
| | - Daniel R. Eacker
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and ConservationUniversity of MontanaMissoula MT 59812 USA
| | - Mark Hebblewhite
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and ConservationUniversity of MontanaMissoula MT 59812 USA
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38
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Jackson J, Mar KU, Htut W, Childs DZ, Lummaa V. Changes in age-structure over four decades were a key determinant of population growth rate in a long-lived mammal. J Anim Ecol 2020; 89:2268-2278. [PMID: 32592591 DOI: 10.1111/1365-2656.13290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/04/2020] [Indexed: 11/27/2022]
Abstract
A changing environment directly influences birth and mortality rates, and thus population growth rates. However, population growth rates in the short term are also influenced by population age-structure. Despite its importance, the contribution of age-structure to population growth rates has rarely been explored empirically in wildlife populations with long-term demographic data. Here we assessed how changes in age-structure influenced short-term population dynamics in a semi-captive population of Asian elephants Elephas maximus. We addressed this question using a demographic dataset of female Asian elephants from timber camps in Myanmar spanning 45 years (1970-2014). First, we explored temporal variation in age-structure. Then, using annual matrix population models, we used a retrospective approach to assess the contributions of age-structure and vital rates to short-term population growth rates with respect to the average environment. Age-structure was highly variable over the study period, with large proportions of juveniles in the years 1970 and 1985, and made a substantial contribution to annual population growth rate deviations. High adult birth rates between 1970 and 1980 would have resulted in large positive population growth rates, but these were prevented by a low proportion of reproductive-aged females. We highlight that an understanding of both age-specific vital rates and age-structure is needed to assess short-term population dynamics. Furthermore, this example from a human-managed system suggests that the importance of age-structure may be accentuated in populations experiencing human disturbance where age-structure is unstable, such as those in captivity or for endangered species. Ultimately, changes to the environment drive population dynamics by influencing birth and mortality rates, but understanding demographic structure is crucial for assessing population growth.
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Affiliation(s)
- John Jackson
- Department of Biology, Interdisciplinary Centre for Population Dynamics, University of Southern Denmark, Odense M, Denmark.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Khyne U Mar
- Department of Biology, University of Turku, Turku, Finland
| | - Win Htut
- Myanma Timber Enterprise, Ministry of Natural Resources and Environment Conservation, Gyogone Forest Compound, Yangon, Myanmar
| | - Dylan Z Childs
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Virpi Lummaa
- Department of Biology, University of Turku, Turku, Finland
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39
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Lachish S, Brandell EE, Craft ME, Dobson AP, Hudson PJ, MacNulty DR, Coulson T. Investigating the Dynamics of Elk Population Size and Body Mass in a Seasonal Environment Using a Mechanistic Integral Projection Model. Am Nat 2020; 196:E23-E45. [PMID: 32673097 DOI: 10.1086/708723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Environmentally mediated changes in body size often underlie population responses to environmental change, yet this is not a universal phenomenon. Understanding when phenotypic change underlies population responses to environmental change is important for obtaining insights and robust predictions of population dynamics in a changing world. We develop a dynamic integral projection model that mechanistically links environmental conditions to demographic rates and phenotypic traits (body size) via changes in resource availability and individual energetics. We apply the model to the northern Yellowstone elk population and explore population responses to changing patterns of seasonality, incorporating the interdependence of growth, demography, and density-dependent processes operating through population feedback on available resources. We found that small changes in body size distributions can have large impacts on population dynamics but need not cause population responses to environmental change. Environmental changes that altered demographic rates directly, via increasing or decreasing resource availability, led to large population impacts in the absence of substantial changes to body size distributions. In contrast, environmentally driven shifts in body size distributions could occur with little consequence for population dynamics when the effect of environmental change on resource availability was small and seasonally restricted and when strong density-dependent processes counteracted expected population responses. These findings highlight that a robust understanding of how associations between body size and demography influence population responses to environmental change will require knowledge of the shape of the relationship between phenotypic distributions and vital rates, the population status with regard to its carrying capacity, and importantly the nature of the environmentally driven change in body size and carrying capacity.
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40
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Hinton JW, Freeman AE, St‐Louis V, Cornicelli L, D'Angelo GJ. Habitat Selection by Female Elk During Minnesota's Agricultural Season. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21850] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Joseph W. Hinton
- Department of Environmental and Forest Biology State University of New York College of Environmental Science and Forestry 1 Forestry Drive Syracuse NY 13210 USA
| | - Alicia E. Freeman
- Department of Biological Sciences Minnesota State University‐Mankato, Trafton Science Center South Mankato MN 56001 USA
| | - Véronique St‐Louis
- Wildlife Biometrics Unit, Division of Fish and Wildlife, Minnesota Department of Natural Resources 5463 W. Broadway Avenue Forest Lake MN 55025 USA
| | - Louis Cornicelli
- Division of Fish and Wildlife, Minnesota Department of Natural Resources 500 Lafayette Road St. Paul MN 51555 USA
| | - Gino J. D'Angelo
- Warnell School of Forestry and Natural Resources, University of Georgia 180 E. Green Street Athens GA 30605 USA
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Denryter K, Cook RC, Cook JG, Parker KL, Gillingham MP. State-dependent foraging by caribou with different nutritional requirements. J Mammal 2020; 101:544-557. [PMID: 32454534 PMCID: PMC7236907 DOI: 10.1093/jmammal/gyaa003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 01/10/2020] [Indexed: 11/20/2022] Open
Abstract
Foraging by animals is hypothesized to be state-dependent, that is, varying with physiological condition of individuals. State often is defined by energy reserves, but state also can reflect differences in nutritional requirements (e.g., for reproduction, lactation, growth, etc.). Testing hypotheses about state-dependent foraging in ungulates is difficult because fine-scale data needed to evaluate these hypotheses generally are lacking. To evaluate whether foraging by caribou (Rangifer tarandus) was state-dependent, we compared bite and intake rates, travel rates, dietary quality, forage selection, daily foraging time, and foraging strategies of caribou with three levels of nutritional requirements (lactating adults, nonlactating adults, subadults 1-2 years old). Only daily foraging times and daily nutrient intakes differed among nutritional classes of caribou. Lactating caribou foraged longer per day than nonlactating caribou-a difference that was greatest at the highest rates of intake, but which persisted even when intake was below requirements. Further, at sites where caribou achieved high rates of intake, caribou in each nutritional class continued foraging even after satisfying daily nutritional requirements, which was consistent with a foraging strategy to maximize energy intake. Foraging time by caribou was partially state-dependent, highlighting the importance of accounting for physiological state in studies of animal behavior. Fine-scale foraging behaviors may influence larger-scale behavioral strategies, with potential implications for conservation and management.
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Affiliation(s)
- Kristin Denryter
- Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, British Columbia, Canada
- Wildlife Branch—Elk and Pronghorn Antelope Program, California Department of Fish and Wildlife, Sacramento, CA, USA
| | - Rachel C Cook
- National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory, La Grande, OR, USA
| | - John G Cook
- National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory, La Grande, OR, USA
| | - Katherine L Parker
- Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Michael P Gillingham
- Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, British Columbia, Canada
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Wilmers CC, Metz MC, Stahler DR, Kohl MT, Geremia C, Smith DW. How climate impacts the composition of wolf-killed elk in northern Yellowstone National Park. J Anim Ecol 2020; 89:1511-1519. [PMID: 32145069 PMCID: PMC7317765 DOI: 10.1111/1365-2656.13200] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 02/04/2020] [Indexed: 11/30/2022]
Abstract
While the functional response of predators is commonly measured, recent work has revealed that the age and sex composition of prey killed is often a better predictor of prey population dynamics because the reproductive value of adult females is usually higher than that of males or juveniles. Climate is often an important mediating factor in determining the composition of predator kills, but we currently lack a mechanistic understanding of how the multiple facets of climate interact with prey abundance and demography to influence the composition of predator kills. Over 20 winters, we monitored 17 wolf packs in Yellowstone National Park and recorded the sex, age and nutritional condition of kills of their dominant prey—elk—in both early and late winter periods when elk are in relatively good and relatively poor condition, respectively. Nutritional condition (as indicated by per cent marrow fat) of wolf‐killed elk varied markedly with summer plant productivity, snow water equivalent (SWE) and winter period. Moreover, marrow was poorer for wolf‐killed bulls and especially for calves than it was for cows. Wolf prey composition was influenced by a complex set of climatic and endogenous variables. In early winter, poor plant growth in either year t or t − 1, or relatively low elk abundance, increased the odds of wolves killing bulls relative to cows. Calves were most likely to get killed when elk abundance was high and when the forage productivity they experienced in utero was poor. In late winter, low SWE and a relatively large elk population increased the odds of wolves killing calves relative to cows, whereas low SWE and poor vegetation productivity 1 year prior together increased the likelihood of wolves killing a bull instead of a cow. Since climate has a strong influence on whether wolves prey on cows (who, depending on their age, are the key reproductive components of the population) or lower reproductive value of calves and bulls, our results suggest that climate can drive wolf predation to be more or less additive from year to year.
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Affiliation(s)
- Christopher C Wilmers
- Center for Integrated Spatial Research, Environmental Studies Department, University of California, Santa Cruz, CA, USA
| | - Matthew C Metz
- Yellowstone Center for Resources, Yellowstone National Park, WY, USA.,Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT, USA
| | - Daniel R Stahler
- Yellowstone Center for Resources, Yellowstone National Park, WY, USA
| | - Michel T Kohl
- Department of Wildland Resources and Ecology Center, Utah State University, Logan, UT, USA
| | - Chris Geremia
- Yellowstone Center for Resources, Yellowstone National Park, WY, USA
| | - Douglas W Smith
- Yellowstone Center for Resources, Yellowstone National Park, WY, USA
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Spitz DB, Rowland MM, Clark DA, Wisdom MJ, Smith JB, Brown CL, Levi T. Behavioral changes and nutritional consequences to elk (
Cervus canadensis
) avoiding perceived risk from human hunters. Ecosphere 2019. [DOI: 10.1002/ecs2.2864] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Derek B. Spitz
- Department of Fisheries and Wildlife Oregon State University Corvallis Oregon 97331 USA
| | - Mary M. Rowland
- U.S. Forest Service Pacific Northwest Research Station La Grande Oregon 97850 USA
| | - Darren A. Clark
- Oregon Department of Fish and Wildlife La Grande Oregon 97850 USA
| | - Michael J. Wisdom
- U.S. Forest Service Pacific Northwest Research Station La Grande Oregon 97850 USA
| | - Joshua B. Smith
- Oregon Department of Fish and Wildlife La Grande Oregon 97850 USA
| | - Casey L. Brown
- Oregon Department of Fish and Wildlife La Grande Oregon 97850 USA
| | - Taal Levi
- Department of Fisheries and Wildlife Oregon State University Corvallis Oregon 97331 USA
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Lehman CP, Rota CT, Millspaugh JJ. Nutritional condition and physiological stress levels of elk in the Black Hills, South Dakota. PeerJ 2019; 7:e7185. [PMID: 31293830 PMCID: PMC6599675 DOI: 10.7717/peerj.7185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/19/2019] [Indexed: 11/20/2022] Open
Abstract
Percent of body fat and physiological stress are important correlates to wildlife demographics. We studied winter percent of body fat and physiological stress levels for a declining elk (Cervus canadensis nelsoni) population in South Dakota, 2011–2013. We obtained percent of winter body fat, pregnancy status, lactation status, and physiological stress data from 58 adult females (2+ years old). We compared physiological stress level data from 2011 with data collected from this same herd when elk densities were much higher (1995–1997). Our objectives were to determine percent of body fat during winter, examine if winter body fat was correlated with pregnancy and lactation status, and quantify and compare physiological stress hormone values from elk in the mid-1990s. Probability of being pregnant increased with higher winter nutritional condition, or percent of body fat; whereas females with a higher probability of previously lactating were lower in winter body fat. Mean fecal glucocorticoid metabolite (FGM) levels in 2011 (mean = 47.78 ng/g, SE = 2.37) were higher during summer compared to data collected in 1995–1997 (mean = 34.21 ng/g, SE = 3.71); however, mean FGM levels during winter did not differ between the two time periods. Although summer levels of FGM have significantly increased since the mid-1990s, we caution against any interpretation of increased FGM levels on elk fitness, as it may not infer biological significance. Mean winter percent of body fat of elk was lower when compared to other populations in the west but this difference does not appear to be limiting vital rates and population growth for this elk herd. We recommend future research focus on summer/autumn data collection to provide a more comprehensive understanding of percent of body fat for elk in our region.
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Affiliation(s)
| | - Christopher T Rota
- School of Natural Resources, Wildlife and Fisheries Resource Program, West Virginia University, Morgantown, WV, USA
| | - Joshua J Millspaugh
- Wildlife Biology Program, W.A. Franke College of Forestry and Conservation, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT, USA
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45
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Contrasting Winter Moose Nutritional Carrying Capacity Models on a Dynamic Landscape. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2019. [DOI: 10.3996/122017-jfwm-104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
AbstractMany models used to estimate nutritional carrying capacity (NCC) for ungulates differ structurally, but the implications of those differences are frequently unclear. We present a comparative analysis of NCC estimates for a large herbivore in a dynamic landscape, using models that differ in structure and scope. We compared three model structures across three estimates of winter ranges under three winter-severity scenarios for an isolated, introduced moose Alces alces population on the Copper River Delta of south-central Alaska. Model estimates of NCC ranged from 205 to 4,592 moose, demonstrating the critical influences of model structure and assumptions when applying NCC. Furthermore, population estimates during recent severe winters suggest that past models underestimated NCC on the Copper River Delta. We conducted a sensitivity analysis of a preferred model and determined that model components with the highest and lowest sensitivity were snow depth and lignin- and tannin-caused reductions in forage nutritional quality, respectively. Our low sensitivity values for lignin and tannin influences on NCC contrast with results in other NCC estimates. Overall, our results reinforce the need for, and will hopefully assist, adaptive management in response to landscape, population, behavioral, and climatic changes on the Copper River Delta, and demonstrate the importance of understanding model assumptions and structure in application of NCC estimates in the management of large herbivores in variable ecosystems.
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Clark DA, Coe PK, Gregory SC, Hedrick MJ, Johnson BK, Jackson DH. Habitat Use Informs Species Needs and Management: A Reply to Maestas et al. J Wildl Manage 2019. [DOI: 10.1002/jwmg.21671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Darren A. Clark
- Oregon Department of Fish and Wildlife 1401 Gekeler Lane La Grande OR 97850 USA
| | - Priscilla K. Coe
- Oregon Department of Fish and Wildlife 1401 Gekeler Lane La Grande OR 97850 USA
| | - Sara C. Gregory
- Oregon Department of Fish and Wildlife 61374 Parrell Road Bend OR 97702 USA
| | - Mary Jo Hedrick
- Oregon Department of Fish and Wildlife 53447 Highway 31 Summer Lake OR 97640 USA
| | - Bruce K. Johnson
- Oregon Department of Fish and Wildlife 1401 Gekeler Lane La Grande OR 97850 USA
| | - DeWaine H. Jackson
- Oregon Department of Fish and Wildlife 4192 N Umpqua Highway Roseburg OR 97470 USA
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Oates BA, Merkle JA, Kauffman MJ, Dewey SR, Jimenez MD, Vartanian JM, Becker SA, Goheen JR. Antipredator response diminishes during periods of resource deficit for a large herbivore. Ecology 2019; 100:e02618. [DOI: 10.1002/ecy.2618] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 10/04/2018] [Accepted: 12/03/2018] [Indexed: 11/10/2022]
Affiliation(s)
- B. A. Oates
- Idaho Department of Fish and Game Boise Idaho 83712 USA
- Wyoming Cooperative Fish and Wildlife Research Unit Department of Zoology and Physiology University of Wyoming Laramie Wyoming 82071 USA
| | - J. A. Merkle
- Wyoming Cooperative Fish and Wildlife Research Unit Department of Zoology and Physiology University of Wyoming Laramie Wyoming 82071 USA
| | - M. J. Kauffman
- U.S. Geological Survey Wyoming Cooperative Fish and Wildlife Research Unit Department of Zoology and Physiology University of Wyoming Laramie Wyoming 82071 USA
| | - S. R. Dewey
- National Park Service Grand Teton National Park Moose Wyoming 83012 USA
| | - M. D. Jimenez
- U.S. Fish and Wildlife Service (retired) Jackson Wyoming 83001 USA
| | | | - S. A. Becker
- U.S. Fish and Wildlife Service Lander Wyoming 82520 USA
| | - J. R. Goheen
- Department of Zoology and Physiology University of Wyoming Laramie Wyoming 82071 USA
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Johnson BK, Jackson DH, Cook RC, Clark DA, Coe PK, Cook JG, Rearden SN, Findholt SL, Noyes JH. Roles of maternal condition and predation in survival of juvenile Elk in Oregon. WILDLIFE MONOGRAPHS 2019. [DOI: 10.1002/wmon.1039] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Bruce K. Johnson
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
| | - Dewaine H. Jackson
- Oregon Department of Fish and Wildlife; 4192 N. Umpqua Highway Roseburg OR 97470 USA
| | - Rachel C. Cook
- National Council for Air and Stream Improvement; 1401 Gekeler Lane La Grande OR 97850 USA
| | - Darren A. Clark
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
| | - Priscilla K. Coe
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
| | - John G. Cook
- National Council for Air and Stream Improvement; 1401 Gekeler Lane La Grande OR 97850 USA
| | - Spencer N. Rearden
- Oregon Cooperative Fish and Wildlife Research Unit; Oregon State University; Corvallis OR 97331 USA
| | - Scott L. Findholt
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
| | - James H. Noyes
- Oregon Department of Fish and Wildlife; 1401 Gekeler Lane La Grande OR 97850 USA
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DeVoe JD, Proffitt KM, Mitchell MS, Jourdonnais CS, Barker KJ. Elk forage and risk tradeoffs during the fall archery season. J Wildl Manage 2019. [DOI: 10.1002/jwmg.21638] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jesse D. DeVoe
- Montana Cooperative Wildlife Research Unit205 Natural Sciences BuildingWildlife Biology ProgramUniversity of MontanaMissoulaMT59812USA
| | - Kelly M. Proffitt
- Montana Department of Fish, Wildlife and Parks1400 South 19th StreetBozemanMT59718USA
| | - Michael S. Mitchell
- U.S. Geological SurveyMontana Cooperative Wildlife Research Unit 205 Natural Sciences BuildingWildlife Biology ProgramUniversity of MontanaMissoulaMT59812USA
| | | | - Kristin J. Barker
- Montana Cooperative Wildlife Research Unit205 Natural Sciences BuildingWildlife Biology ProgramUniversity of MontanaMissoulaMT59812USA
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Stokely TD, Verschuyl J, Hagar JC, Betts MG. Herbicides and herbivory interact to drive plant community and crop-tree establishment. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:2011-2023. [PMID: 30027661 DOI: 10.1002/eap.1777] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/25/2018] [Accepted: 06/19/2018] [Indexed: 06/08/2023]
Abstract
Land management practices often directly alter vegetation structure and composition, but the degree to which ecological processes such as herbivory interact with management to influence biodiversity is less well understood. We hypothesized that large herbivores compound the effects of intensive forest management on early seral plant communities and plantation establishment (i.e., tree survival and growth), and the degree of such effects is dependent on the intensity of management practices. We established 225-m2 wild-ungulate (deer and elk) exclosures, nested within a manipulated gradient of management intensity (no-herbicide control, light herbicide, moderate herbicide, and intensive herbicide treatments), replicated at the scale of whole harvest units (10-19 ha). Vegetation structure, composition, and crop-tree responses to herbivory varied across the gradient of herbicide application during the first two years of stand establishment, with herbivory effects most evident at light and moderate herbicide treatments. In the moderate herbicide treatment, which approximates management applied to >2.5 million hectares in the Pacific Northwest, United States, foraging by deer and elk resulted in simplified, low-cover plant communities more closely resembling the intensive herbicide treatment. Herbivory further suppressed the growth of competing vegetation in the light herbicide treatment, improving crop-tree survival, and providing early evidence of an ecosystem service. By changing community composition and vegetation structure, intensive forest management alters foraging selectivity and subsequent plant-herbivore interactions; initial shifts in early seral communities are likely to influence understory plant communities and tree growth in later stages of forest development.
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Affiliation(s)
- Thomas D Stokely
- Department of Forest Ecosystems & Society, Forest Biodiversity Research Network, Oregon State University, Corvallis, Oregon, 97331, USA
| | - Jake Verschuyl
- National Council for Air & Stream Improvement, Western Sustainable Forestry Program, Anacortes, Washington, 98221, USA
| | - Joan C Hagar
- U.S. Geological Survey, Forest & Rangeland Ecosystem Science Center, Corvallis, Oregon, 97331, USA
| | - Matthew G Betts
- Department of Forest Ecosystems & Society, Forest Biodiversity Research Network, Oregon State University, Corvallis, Oregon, 97331, USA
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