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Beardsell A, Berteaux D, Dulude-De Broin F, Gauthier G, Clermont J, Gravel D, Bêty J. Predator-mediated interactions through changes in predator home range size can lead to local prey exclusion. Proc Biol Sci 2023; 290:20231154. [PMID: 37554032 PMCID: PMC10410220 DOI: 10.1098/rspb.2023.1154] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/12/2023] [Indexed: 08/10/2023] Open
Abstract
The strength of indirect biotic interactions is difficult to quantify in the wild and can alter community composition. To investigate whether the presence of a prey species affects the population growth rate of another prey species, we quantified predator-mediated interaction strength using a multi-prey mechanistic model of predation and a population matrix model. Models were parametrized using behavioural, demographic and experimental data from a vertebrate community that includes the arctic fox (Vulpes lagopus), a predator feeding on lemmings and eggs of various species such as sandpipers and geese. We show that the positive effects of the goose colony on sandpiper nesting success (due to reduction of search time for sandpiper nests) were outweighed by the negative effect of an increase in fox density. The fox numerical response was driven by changes in home range size. As a result, the net interaction from the presence of geese was negative and could lead to local exclusion of sandpipers. Our study provides a rare empirically based model that integrates mechanistic multi-species functional responses and behavioural processes underlying the predator numerical response. This is an important step forward in our ability to quantify the consequences of predation for community structure and dynamics.
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Affiliation(s)
- Andréanne Beardsell
- Chaire de recherche du Canada en biodiversité nordique, Centre d'études nordiques et Centre de la science de la biodiversité du Québec, Université du Québec à Rimouski, Rimouski, Québec, Canada G5L 3A1
| | - Dominique Berteaux
- Chaire de recherche du Canada en biodiversité nordique, Centre d'études nordiques et Centre de la science de la biodiversité du Québec, Université du Québec à Rimouski, Rimouski, Québec, Canada G5L 3A1
| | | | - Gilles Gauthier
- Département de biologie et Centre d'études nordiques, Université Laval, Québec, Canada G1V 0A6
| | - Jeanne Clermont
- Chaire de recherche du Canada en biodiversité nordique, Centre d'études nordiques et Centre de la science de la biodiversité du Québec, Université du Québec à Rimouski, Rimouski, Québec, Canada G5L 3A1
| | - Dominique Gravel
- Département de biologie et Centre d'études nordiques, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - Joël Bêty
- Chaire de recherche du Canada en biodiversité nordique, Centre d'études nordiques et Centre de la science de la biodiversité du Québec, Université du Québec à Rimouski, Rimouski, Québec, Canada G5L 3A1
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Zabala J, Trexler JC, Jayasena N, Frederick P. Timing and magnitude of net methylmercury effects on waterbird reproductive output are dependent on food availability. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:159706. [PMID: 36309287 DOI: 10.1016/j.scitotenv.2022.159706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Mercury (Hg) is a globally distributed pollutant. Its sub-lethal effects on reproduction of birds have been used as indicators of contamination and of potential demographic effects. However, studies typically used single endpoints that might not be representative of entire reproductive cycle. To estimate timing and net cumulative effects of Hg exposure under field conditions, we used observational data over 11 years from >1200 nests of great egrets breeding under temporally and spatially varying food availability and Hg exposures in the Florida Everglades. We collected measures of fish biomass and availability (>100 locations annually) and used four avian reproductive endpoints that represented the entire breeding cycle. We calculated net reproductive loss by adding estimated Hg effects on failures prior to egg laying, clutch size, hatching success and nestling survival in response to food availability and Hg exposure. To validate and assess results of the observational egret study, we ran the same analyses with data of captive breeding white ibises experimentally exposed to Hg with ad libitum food over 3 years. We found large (>50 %) reductions in great egret offspring with high Hg exposure (18 μg/g dw THg nestling feather, ~0.7 μg/g ww whole egg THg) and high food availability, and even larger reductions (up to 100 %) with high Hg exposure and low food. Timing and the relative contribution of different endpoints to overall reproductive failure varied with food availability. Failures prior to egg laying were relevant at all food availabilities and proportionally most important during high food availability (~70 % of total losses). Under high food, post-hatching failures increased moderately with increasing exposure (~10 % of total losses), and under low food, hatching failures became dominant (~50 % of total losses). Patterns of failure of captive white ibis fed ad libitum resembled those of great egrets under high food availability but differed in total magnitude. We suggest that, a) net reproductive effects of Hg in free-ranging animals are probably much higher than generally reported in studies using single endpoints, b) Hg effect sizes vary considerably among different endpoints and c) food availability is a strong driver of timing and net effects of Hg exposure.
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Affiliation(s)
- Jabi Zabala
- Department of Zoology and Animal Cell Biology, University of the Basque Country, UPV/EHU, C/Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Araba, Basque Country, Spain; Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA.
| | - Joel C Trexler
- Department of Biological Sciences, Florida International University, Miami, FL, USA; Coastal & Marine laboratory, Florida State University, St. Teresa, FL, USA
| | - Nilmini Jayasena
- Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya, Sri Lanka
| | - Peter Frederick
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA
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Sex-specific effects of capital resources on reproductive timing and success in red squirrels. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03245-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Vettorazzi M, Mogensen N, Kaelo B, Broekhuis F. Understanding the effects of seasonal variation in prey availability on prey switching by large carnivores. J Zool (1987) 2022. [DOI: 10.1111/jzo.13013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- M. Vettorazzi
- Wildlife Ecology and Conservation Group Wageningen University and Research Wageningen The Netherlands
| | - N. Mogensen
- Mara Predator Conservation Programme Kenya Wildlife Trust Nairobi Kenya
| | - B. Kaelo
- Mara Predator Conservation Programme Kenya Wildlife Trust Nairobi Kenya
| | - F. Broekhuis
- Wildlife Ecology and Conservation Group Wageningen University and Research Wageningen The Netherlands
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Wilson AE, Michaud SA, Jackson AM, Stenhouse G, McClelland CJR, Coops NC, Janz DM. Protein biomarkers in serum as a conservation tool to assess reproduction: a case study on brown bears ( Ursus arctos). CONSERVATION PHYSIOLOGY 2021; 9:coab091. [PMID: 34888057 PMCID: PMC8651255 DOI: 10.1093/conphys/coab091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/26/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
Monitoring the reproductive characteristics of a species can complement existing conservation strategies by understanding the mechanisms underlying demography. However, methodology to determine important aspects of female reproductive biology is often absent in monitoring programs for large mammals. Protein biomarkers may be a useful tool to detect physiological changes that are indicative of reproductive state. This study aimed to identify protein biomarkers of reproductive status in serum collected from free-ranging female brown bears (Ursus arctos) in Alberta, Canada, from 2001 to 2018. We hypothesized that the expression of proteins related to reproduction in addition to energetics and stress can be used to answer specific management-focused questions: (i) identify when a female is pregnant, (ii) detect if a female is lactating, (iii) determine age of sexual maturity (i.e. primiparity) and (iv) assess female fertility (i.e. reproduction rate). Furthermore, we investigated if silver spoon effects (favourable early life conditions provide fitness benefits through adulthood) could be determined using protein expression. A target panel of 19 proteins with established relationships to physiological function was measured by peptide-based analysis using liquid chromatography and multiple reaction monitoring mass spectrometry and their differential expression was evaluated using a Wilcoxon signed-rank test. We found biomarkers of pregnancy (apolipoprotein B-100 and afamin), lactation (apolipoprotein B-100 and alpha-2-macroglobulin) and sexual maturity (corticosteroid-binding globulin), but there were no statistically significant relationships with protein expression and fertility. The expression of proteins related to reproduction (afamin) and energetics (vitamin-D binding protein) was associated with the nutritional quality of the individual's present habitat rather than their early life habitat. This study highlights potential biomarkers of reproductive status and provides additional methods for monitoring physiological function in wildlife to inform conservation.
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Affiliation(s)
- Abbey E Wilson
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada
| | - Sarah A Michaud
- The University of Victoria Genome BC Proteomics Centre, 4464 Markham St #3101, Victoria, British Columbia V8Z 7X8, Canada
| | - Angela M Jackson
- The University of Victoria Genome BC Proteomics Centre, 4464 Markham St #3101, Victoria, British Columbia V8Z 7X8, Canada
| | - Gordon Stenhouse
- Grizzly Bear Program, fRI Research, 1176 Switzer Drive, Hinton, Alberta T7V 1V3, Canada
| | | | - Nicholas C Coops
- Department of Forest Resource Management, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - David M Janz
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada
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Fatty acid profiles of feeding and fasting bears: estimating calibration coefficients, the timeframe of diet estimates, and selective mobilization during hibernation. J Comp Physiol B 2021; 192:379-395. [PMID: 34687352 DOI: 10.1007/s00360-021-01414-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 09/20/2021] [Accepted: 10/03/2021] [Indexed: 10/20/2022]
Abstract
Accurate information on diet composition is central to understanding and conserving carnivore populations. Quantitative fatty acid signature analysis (QFASA) has emerged as a powerful tool for estimating the diets of predators, but ambiguities remain about the timeframe of QFASA estimates and the need to account for species-specific patterns of metabolism. We conducted a series of feeding experiments with four juvenile male brown bears (Ursus arctos) to (1) track the timing of changes in adipose tissue composition and QFASA diet estimates in response to a change in diet and (2) quantify the relationship between consumer and diet FA composition (i.e., determine "calibration coefficients"). Bears were fed three compositionally distinct diets for 90-120 days each. Two marine-based diets were intended to approximate the lipid content and composition of the wild diet of polar bears (U. maritimus). Bear adipose tissue composition changed quickly in the direction of the diet and showed evidence of stabilization after 60 days. During hibernation, FA profiles were initially stable but diet estimates after 10 weeks were sensitive to calibration coefficients. Calibration coefficients derived from the marine-based diets were broadly similar to each other and to published values from marine-fed mink (Mustela vison), which have been used as a model for free-ranging polar bears. For growing bears on a high-fat diet, the temporal window for QFASA estimates was 30-90 days. Although our results reinforce the importance of accurate calibration, the similarities across taxa and diets suggest it may be feasible to develop a generalized QFASA approach for mammalian carnivores.
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Nater CR, Eide NE, Pedersen ÅØ, Yoccoz NG, Fuglei E. Contributions from terrestrial and marine resources stabilize predator populations in a rapidly changing climate. Ecosphere 2021. [DOI: 10.1002/ecs2.3546] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Chloé R. Nater
- Norwegian Polar Institute Tromsø Norway
- Centre for Biodiversity Dynamics Norwegian University of Science and Technology Trondheim Norway
- Department of Arctic and Marine Biology UIT – The Arctic University of Norway Tromsø Norway
| | - Nina E. Eide
- Norwegian Institute for Nature Research Trondheim Norway
| | | | - Nigel G. Yoccoz
- Department of Arctic and Marine Biology UIT – The Arctic University of Norway Tromsø Norway
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