1
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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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2
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Van Schmidt ND, Beissinger SR. The rescue effect and inference from isolation-extinction relationships. Ecol Lett 2020; 23:598-606. [PMID: 31981448 DOI: 10.1111/ele.13460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 12/23/2019] [Indexed: 11/28/2022]
Abstract
The rescue effect in metapopulations hypothesises that less isolated patches are unlikely to go extinct because recolonisation may occur between breeding seasons ('recolonisation rescue'), or immigrants may sufficiently bolster population size to prevent extinction altogether ('demographic rescue'). These mechanisms have rarely been demonstrated directly, and most evidence of the rescue effect is from relationships between isolation and extinction. We determined the frequency of recolonisation rescue for metapopulations of black rails (Laterallus jamaicensis) and Virginia rails (Rallus limicola) from occupancy surveys conducted during and between breeding seasons, and assessed the reliability of inferences about the occurrence of rescue drawn from isolation-extinction relationships, including autologistic isolation measures that corrected for unsurveyed patches and imperfect detection. Recolonisation rescue occurred at expected rates, but was elevated during periods of disturbance that resulted in non-equilibrium metapopulation dynamics. Inferences from extinction-isolation relationships were unreliable, particularly for autologistic measures and for the more vagile Virginia rail.
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Affiliation(s)
- Nathan D Van Schmidt
- Department of Environmental Science, Policy, and Management, University of California - Berkeley, Berkeley, CA, USA
| | - Steven R Beissinger
- Department of Environmental Science, Policy, and Management, University of California - Berkeley, Berkeley, CA, USA.,Museum of Vertebrate Zoology, University of California - Berkeley, Berkeley, CA, USA
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3
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Millon A, Lambin X, Devillard S, Schaub M. Quantifying the contribution of immigration to population dynamics: a review of methods, evidence and perspectives in birds and mammals. Biol Rev Camb Philos Soc 2019; 94:2049-2067. [DOI: 10.1111/brv.12549] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 07/10/2019] [Accepted: 07/17/2019] [Indexed: 02/04/2023]
Affiliation(s)
- Alexandre Millon
- Aix Marseille Université, CNRS, IRD, Avignon Université, IMBE, Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale, Technopôle Arbois‐Méditerranée, Bât. Villemin – BP 80 F‐13545 Aix‐en‐Provence cedex 04 France
| | - Xavier Lambin
- School of Biological SciencesUniversity of Aberdeen Tillydrone Avenue, Zoology Building, University of Aberdeen, AB24 2TZ Aberdeen U.K
| | - Sébastien Devillard
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive F‐69100 Villeurbanne France
| | - Michael Schaub
- Swiss Ornithological Institute Seerose 1, 6204 Sempach Switzerland
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4
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Integrated population models: powerful methods to embed individual processes in population dynamics models. Ecology 2019; 100:e02715. [DOI: 10.1002/ecy.2715] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 11/05/2018] [Accepted: 01/02/2019] [Indexed: 12/29/2022]
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5
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Porteus TA, Reynolds JC, McAllister MK. Quantifying the rate of replacement by immigration during restricted-area control of red fox in different landscapes. WILDLIFE BIOLOGY 2018. [DOI: 10.2981/wlb.00416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Tom A. Porteus
- T. A. Porteus (http://orcid.org/0000-0003-0666-2593) , Dept of Zoology, Univ. of British Columbia, Vancouver, BC, Canada
| | - Jonathan C. Reynolds
- Present address and address for J. C. Reynolds, Game and Wildlife Conservation Trust, Burgate Manor, Fordingbridge, SP6 1EF, UK
| | - Murdoch K. McAllister
- M. K. McAllister, Inst. for the Oceans and Fisheries, Univ. of British Columbia, Vancouver, BC, Canada
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6
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Heinrichs JA, Lawler JJ, Schumaker NH, Wilsey CB, Monroe KC, Aldridge CL. A multispecies test of source-sink indicators to prioritize habitat for declining populations. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2018; 32:648-659. [PMID: 29193292 DOI: 10.1111/cobi.13058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/23/2017] [Accepted: 10/20/2017] [Indexed: 06/07/2023]
Abstract
For species at risk of decline or extinction in source-sink systems, sources are an obvious target for habitat protection actions. However, the way in which source habitats are identified and prioritized can reduce the effectiveness of conservation actions. Although sources and sinks are conceptually defined using both demographic and movement criteria, simplifications are often required in systems with limited data. To assess the conservation outcomes of alternative source metrics and resulting prioritizations, we simulated population dynamics and extinction risk for 3 endangered species. Using empirically based habitat population models, we linked habitat maps with measured site- or habitat-specific demographic conditions, movement abilities, and behaviors. We calculated source-sink metrics over a range of periods of data collection and prioritized consistently high-output sources for conservation. We then tested whether prioritized patches identified the habitats that most affected persistence by removing them and measuring the population response. Conservation decisions based on different source-sink metrics and durations of data collection affected species persistence. Shorter time series obscured the ability of metrics to identify influential habitats, particularly in temporally variable and slowly declining populations. Data-rich source-sink metrics that included both demography and movement information did not always identify the habitats with the greatest influence on extinction risk. In some declining populations, patch abundance better predicted influential habitats for short-term regional persistence. Because source-sink metrics (i.e., births minus deaths; births and immigrations minus deaths and emigration) describe net population conditions and cancel out gross population counts, they may not adequately identify influential habitats in declining populations. For many nonequilibrium populations, new metrics that maintain the counts of individual births, deaths, and movement may provide additional insight into habitats that most influence persistence.
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Affiliation(s)
- Julie A Heinrichs
- School of Environmental and Forest Sciences, University of Washington, P.O. Box 352100, Seattle, WA 98195, U.S.A
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, U.S.A
| | - Joshua J Lawler
- School of Environmental and Forest Sciences, University of Washington, P.O. Box 352100, Seattle, WA 98195, U.S.A
| | - Nathan H Schumaker
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, U.S.A
| | - Chad B Wilsey
- School of Environmental and Forest Sciences, University of Washington, P.O. Box 352100, Seattle, WA 98195, U.S.A
| | - Kira C Monroe
- School of Environmental and Forest Sciences, University of Washington, P.O. Box 352100, Seattle, WA 98195, U.S.A
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, U.S.A
| | - Cameron L Aldridge
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, U.S.A
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7
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Manlik O, Lacy RC, Sherwin WB. Applicability and limitations of sensitivity analyses for wildlife management. J Appl Ecol 2017. [DOI: 10.1111/1365-2664.13044] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Oliver Manlik
- School of Biological, Earth and Environmental Sciences; Evolution and Ecology Research Centre; University of New South Wales; Sydney NSW Australia
| | | | - William B. Sherwin
- School of Biological, Earth and Environmental Sciences; Evolution and Ecology Research Centre; University of New South Wales; Sydney NSW Australia
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8
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Balme GA, Pitman RT, Robinson HS, Miller JRB, Funston PJ, Hunter LTB. Leopard distribution and abundance is unaffected by interference competition with lions. Behav Ecol 2017. [DOI: 10.1093/beheco/arx098] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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9
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Pakanen VM, Aikio S, Luukkonen A, Koivula K. Grazed wet meadows are sink habitats for the southern dunlin ( Calidris alpina schinzii) due to nest trampling by cattle. Ecol Evol 2016; 6:7176-7187. [PMID: 28725390 PMCID: PMC5513266 DOI: 10.1002/ece3.2369] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 07/14/2016] [Accepted: 07/18/2016] [Indexed: 11/29/2022] Open
Abstract
The effect of habitat management is commonly evaluated by measuring population growth, which does not distinguish changes in reproductive success from changes in survival or the effects of immigration or emigration. Management has rarely been evaluated considering complete life cycle of the target organisms, including also possible negative impacts from management. We evaluated the effectiveness of cattle grazing in the restoration of coastal meadows as a breeding habitat for small and medium‐sized ground‐nesting birds by examining the size and demography of a southern dunlin (Calidris alpina schinzii) breeding population. Using a stochastic renesting model that includes within‐season variation in breeding parameters, we evaluated the effect of grazing time and stocking rates on reproduction. The census data indicated that the population was stable when nest trampling was prevented, but detailed demographic models showed that the population on managed meadows was a sink that persisted by attracting immigrants. Even small reductions in reproductive success caused by trampling were detrimental to long‐term viability. We suggest that the best management strategy is to postpone grazing to after the 19th of June, which is about three weeks later than what is optimal from the farmer's point of view. The differing results from the two evaluation approaches warn against planning and evaluating management only based on census population size and highlight the need to consider target‐specific life history characteristics and demography. Even though grazing management is crucial for creating and maintaining suitable habitats, we found that it was insufficient in maintaining a viable population without additional measures that increase nest success. In the presently studied case and in populations with similar breeding cycles, impacts from nest trampling can be avoided by starting grazing when about 70% of the breeding season has past.
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Affiliation(s)
- Veli-Matti Pakanen
- Department of Ecology University of Oulu PO Box 3000 FIN-90014 Oulu Finland
| | - Sami Aikio
- Department of Ecology University of Oulu PO Box 3000 FIN-90014 Oulu Finland.,Finnish Museum of Natural History Botany Unit University of Helsinki PO Box 7 FIN-00014 Helsinki Finland
| | - Aappo Luukkonen
- Department of Ecology University of Oulu PO Box 3000 FIN-90014 Oulu Finland
| | - Kari Koivula
- Department of Ecology University of Oulu PO Box 3000 FIN-90014 Oulu Finland
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10
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Munilla I, Genovart M, Paiva VH, Velando A. Colony Foundation in an Oceanic Seabird. PLoS One 2016; 11:e0147222. [PMID: 26909694 PMCID: PMC4766187 DOI: 10.1371/journal.pone.0147222] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/30/2015] [Indexed: 11/19/2022] Open
Abstract
Seabirds are colonial vertebrates that despite their great potential for long-range dispersal and colonization are reluctant to establish in novel locations, often recruiting close to their natal colony. The foundation of colonies is therefore a rare event in most seabird species and little is known about the colonization process in this group. The Cory’s shearwater (Calonectris diomedea) is a pelagic seabird that has recently established three new colonies in Galicia (NE Atlantic) thus expanding its distribution range 500 km northwards. This study aimed to describe the establishment and early progress of the new Galician populations and to determine the genetic and morphometric characteristics of the individuals participating in these foundation events. Using 10 microsatellite loci, we tested the predictions supported by different seabird colonization models. Possibly three groups of non-breeders, adding up to around 200 birds, started visiting the Galician colonies in the mid 2000’s and some of them eventually laid eggs and reproduced, thus establishing new breeding colonies. The Galician populations showed a high genetic diversity and a frequency of private alleles similar to or even higher than some of the large historical populations. Most individuals were assigned to several Atlantic populations and a few (if any) to Mediterranean colonies. Our study suggests that a large and admixed population is settling in Galicia, in agreement with predictions from island metapopulation models of colonization. Multiple source colonies imply that some birds colonizing Galicia were dispersing from very distant colonies (> 1500 km). Long-distance colonizations undertaken by relatively large and admixed groups of colonizers can help to explain the low levels of genetic structure over vast areas that are characteristic of most oceanic seabird species.
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Affiliation(s)
- Ignacio Munilla
- Departamento de Botánica, Facultade de Bioloxía, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
- * E-mail: (AV); (IM)
| | - Meritxell Genovart
- Departamento de Botánica, Facultade de Bioloxía, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
| | - Vitor H. Paiva
- Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Alberto Velando
- Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Vigo, Galicia, Spain
- * E-mail: (AV); (IM)
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11
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Lampila S, Wistbacka R, Mäkelä A, Orell M. Survival and population growth rate of the threatened Siberian flying squirrel (Pteromys volans) in a fragmented forest landscape. ECOSCIENCE 2015. [DOI: 10.2980/16-1-3184] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Furrer RD, Pasinelli G. Empirical evidence for source-sink populations: a review on occurrence, assessments and implications. Biol Rev Camb Philos Soc 2015; 91:782-95. [DOI: 10.1111/brv.12195] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 04/14/2015] [Accepted: 04/22/2015] [Indexed: 11/27/2022]
Affiliation(s)
- Roman D. Furrer
- Swiss Ornithological Institute; Seerose 1 CH-6204 Sempach Switzerland
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13
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Beasley JC, Dharmarajan G, Rhodes OE. Melding kin structure and demography to elucidate source and sink habitats in fragmented landscapes. Ecosphere 2015. [DOI: 10.1890/es14-00274.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- J. C. Beasley
- Department of Forestry and Natural Resources, 195 Marsteller Street, Purdue University, West Lafayette, Indiana 47907 USA
| | - G. Dharmarajan
- Department of Forestry and Natural Resources, 195 Marsteller Street, Purdue University, West Lafayette, Indiana 47907 USA
| | - O. E. Rhodes
- Department of Forestry and Natural Resources, 195 Marsteller Street, Purdue University, West Lafayette, Indiana 47907 USA
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14
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Li R, Xu M, Wong MHG, Qiu S, Sheng Q, Li X, Song Z. Climate change-induced decline in bamboo habitats and species diversity: implications for giant panda conservation. DIVERS DISTRIB 2014. [DOI: 10.1111/ddi.12284] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Renqiang Li
- Key Laboratory of Ecosystem Network Observation and Modeling; Institute of Geographic Sciences and Natural Resources; the Chinese Academy of Sciences; Beijing China
| | - Ming Xu
- Department of Ecology, Evolution and Natural Resources; Rutgers University; New Brunswick NJ 08901 USA
| | - Michelle Hang Gi Wong
- Key Laboratory of Ecosystem Network Observation and Modeling; Institute of Geographic Sciences and Natural Resources; the Chinese Academy of Sciences; Beijing China
| | - Shuai Qiu
- Key Laboratory of Ecosystem Network Observation and Modeling; Institute of Geographic Sciences and Natural Resources; the Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Qingkai Sheng
- Key Laboratory of Ecosystem Network Observation and Modeling; Institute of Geographic Sciences and Natural Resources; the Chinese Academy of Sciences; Beijing China
| | - Xinhai Li
- Key Laboratory of the Zoological Systematics and Evolution; Institute of Zoology; the Chinese Academy of Sciences; Beijing China
| | - Zengming Song
- PRC-GEF Partnership on Land Degradation in Dryland Ecosystems; Beijing China
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15
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Using integrated population models to improve conservation monitoring: California spotted owls as a case study. Ecol Modell 2014. [DOI: 10.1016/j.ecolmodel.2014.07.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Fu L, Tang S, Liu Y, Sharma RP, Zhang H, Lei Y, Wang H, Song X. Developing, testing and application of rodent population dynamics and capture models based on an adjusted Leslie matrix-based population approach. INT J BIOMATH 2014. [DOI: 10.1142/s1793524514500247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Small rodents in general and the multimammate rat Apodemus agrarius in particular, damage crops and cause major economic losses in China. Therefore, accurate predictions of the population size of A. agrarius and an efficient control strategy are urgently needed. We developed a population dynamics model by applying a Leslie matrix method, and a capture model based on optimal harvesting theory for A. agrarius. Our models were parametrized using demographic estimates from a capture–mark–recapture (CMR) study conducted on the Qinshui Forest Farm in Northwestern China. The population dynamics model incorporated 12 equally balanced age groups and included immigration and emigration parameters. The model was evaluated by assessing the predictions for four years based on the known starting population in 2004 from the 2004–2007 CMR data. The capture model incorporated two functional age categories (juvenile and adult) and used density-dependent and density-independent factors. The models were used to assess the effect of rodent control measures between 2004 and 2023 on population dynamics and the resulting numbers of rats. Three control measures affecting survival rates were considered. We found that the predicted population dynamics of A. agrarius between 2004 and 2007 compared favorably with the observed population dynamics. The models predicted that the population sizes of A. agrarius in the period between 2004 and 2023 under the control measure applied in August 2004 were very similar to the optimal population sizes, and no significant difference was found between the two population sizes. We recommend using the population dynamics and capture models based on CMR-estimated demographic schedules for rodent, provided these data are available. The models that we have developed have the potential to play an important role in predicting the effects of rodent management and in evaluating different control strategies.
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Affiliation(s)
- Liyong Fu
- Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, P. R. China
| | - Shouzheng Tang
- Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, P. R. China
| | - Yingan Liu
- Department of Mathematics, Nanjing Forest University, Nanjing, Jiangsu Province 210037, P. R. China
| | - Ram P. Sharma
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Ås 1432, Norway
| | - Huiru Zhang
- Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, P. R. China
| | - Yuancai Lei
- Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, P. R. China
| | - Hong Wang
- Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, P. R. China
| | - Xinyu Song
- Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, P. R. China
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17
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Holyoak M, Meese RJ, Graves EE. Combining site occupancy, breeding population sizes and reproductive success to calculate time-averaged reproductive output of different habitat types: an application to Tricolored Blackbirds. PLoS One 2014; 9:e96980. [PMID: 24817307 PMCID: PMC4016217 DOI: 10.1371/journal.pone.0096980] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 04/15/2014] [Indexed: 11/19/2022] Open
Abstract
In metapopulations in which habitat patches vary in quality and occupancy it can be complicated to calculate the net time-averaged contribution to reproduction of particular populations. Surprisingly, few indices have been proposed for this purpose. We combined occupancy, abundance, frequency of occurrence, and reproductive success to determine the net value of different sites through time and applied this method to a bird of conservation concern. The Tricolored Blackbird (Agelaius tricolor) has experienced large population declines, is the most colonial songbird in North America, is largely confined to California, and breeds itinerantly in multiple habitat types. It has had chronically low reproductive success in recent years. Although young produced per nest have previously been compared across habitats, no study has simultaneously considered site occupancy and reproductive success. Combining occupancy, abundance, frequency of occurrence, reproductive success and nest failure rate we found that that large colonies in grain fields fail frequently because of nest destruction due to harvest prior to fledging. Consequently, net time-averaged reproductive output is low compared to colonies in non-native Himalayan blackberry or thistles, and native stinging nettles. Cattail marshes have intermediate reproductive output, but their reproductive output might be improved by active management. Harvest of grain-field colonies necessitates either promoting delay of harvest or creating alternative, more secure nesting habitats. Stinging nettle and marsh colonies offer the main potential sources for restoration or native habitat creation. From 2005-2011 breeding site occupancy declined 3x faster than new breeding colonies were formed, indicating a rapid decline in occupancy. Total abundance showed a similar decline. Causes of variation in the value for reproduction of nesting substrates and factors behind continuing population declines merit urgent investigation. The method we employ should be useful in other metapopulation studies for calculating time-averaged reproductive output for different sites.
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Affiliation(s)
- Marcel Holyoak
- Department of Environmental Science and Policy, University of California Davis, Davis, California, United States of America
| | - Robert J. Meese
- Department of Environmental Science and Policy, University of California Davis, Davis, California, United States of America
| | - Emily E. Graves
- Department of Wildlife, Fish and Conservation Biology and Avian Sciences Graduate Group, University of California Davis, Davis, California, United States of America
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18
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Peery MZ, Pauli JN. Shade-grown cacao supports a self-sustaining population of two-toed but not three-toed sloths. J Appl Ecol 2014. [DOI: 10.1111/1365-2664.12182] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Zachariah Peery
- Department of Forest and Wildlife Ecology; University of Wisconsin-Madison; 1630 Linden Drive Madison WI 53706 USA
| | - Jonathan N. Pauli
- Department of Forest and Wildlife Ecology; University of Wisconsin-Madison; 1630 Linden Drive Madison WI 53706 USA
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19
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Tempel DJ, Gutiérrez RJ, Whitmore SA, Reetz MJ, Stoelting RE, Berigan WJ, Seamans ME, Zachariah Peery M. Effects of forest management on California Spotted Owls: implications for reducing wildfire risk in fire‐prone forests. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2014; 24:2089-106. [PMID: 29188683 DOI: 10.1890/13-2192.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Management of many North American forests is challenged by the need to balance the potentially competing objectives of reducing risks posed by high-severity wildfires and protecting threatened species. In the Sierra Nevada, California, concern about high-severity fires has increased in recent decades but uncertainty exists over the effects of fuel-reduction treatments on species associated with older forests, such as the California Spotted Owl (Strix occidentalis occidentalis). Here, we assessed the effects of forest conditions, fuel reductions, and wildfire on a declining population of Spotted Owls in the central Sierra Nevada using 20 years of demographic data collected at 74 Spotted Owl territories. Adult survival and territory colonization probabilities were relatively high, while territory extinction probability was relatively low, especially in territories that had relatively large amounts of high canopy cover (≥70%) forest. Reproduction was negatively associated with the area of medium-intensity timber harvests characteristic of proposed fuel treatments. Our results also suggested that the amount of edge between older forests and shrub/sapling vegetation and increased habitat heterogeneity may positively influence demographic rates of Spotted Owls. Finally, high-severity fire negatively influenced the probability of territory colonization. Despite correlations between owl demographic rates and several habitat variables, life stage simulation (sensitivity) analyses indicated that the amount of forest with high canopy cover was the primary driver of population growth and equilibrium occupancy at the scale of individual territories. Greater than 90% of medium-intensity harvests converted high-canopy-cover forests into lower-canopy-cover vegetation classes, suggesting that landscape-scale fuel treatments in such stands could have short-term negative impacts on populations of California Spotted Owls. Moreover, high-canopy-cover forests declined by an average of 7.4% across territories during our study, suggesting that habitat loss could have contributed to declines in abundance and territory occupancy. We recommend that managers consider the existing amount and spatial distribution of high-canopy forest before implementing fuel treatments within an owl territory, and that treatments be accompanied by a rigorous monitoring program.
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20
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Schaub M, Jakober H, Stauber W. Strong contribution of immigration to local population regulation: evidence from a migratory passerine. Ecology 2013; 94:1828-38. [PMID: 24015526 DOI: 10.1890/12-1395.1] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A mechanistic understanding of the dynamics of populations requires knowledge about the variation of the underlying demographic rates and about the reasons for their variability. In geographically open populations, immigration is often necessary to prevent declines, but little is known about whether immigration can contribute to its regulation. We studied the dynamics of a Red-backed Shrike population (Lanius collurio) over 36 years in Germany with a Bayesian integrated population model. We estimated mean and temporal variability of population sizes, productivity, apparent survival, and immigration. We assessed how strongly the demographic rates were correlated with population growth to understand the demographic reasons of population change and how strongly the demographic rates were correlated with population size to identify possible density-dependent mechanisms. The shrike population varied between 35 and 74 breeding pairs but did not show a significant trend in population size over time (growth rate 1.002 +/- 0.001 [mean +/- SD]). Apparent survival of females (juveniles 0.06 +/- 0.01; adults 0.37 +/- 0.03) was lower than that of males (juveniles 0.10 +/- 0.01; adults 0.44 +/- 0.02). Immigration rates were substantial and higher in females (0.56 +/- 0.02) than in males (0.43 +/- 0.02), and average productivity was 2.76 +/- 0.14. Without immigration, the Red-backed Shrike population would have declined strongly. Immigration was the strongest driver for the number of females while local recruitment was the most important driver for the number of males. Immigration of both sexes and productivity, but not local recruitment and survival, were subject to density dependence. Density-dependent productivity was not effectively regulating the local population but may have contributed to regulate shrike populations at larger spatial scales. These findings suggest that immigration is not only an important component to prevent a geographically open population from decline, but that it can also contribute to its regulation.
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Affiliation(s)
- Michael Schaub
- Swiss Ornithological Institute, CH-6204 Sempach, Switzerland.
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Contasti AL, Van Beest FM, Vander Wal E, Mcloughlin PD. Identifying hidden sinks in growing populations from individual fates and movements: The feral horses of Sable Island. J Wildl Manage 2013. [DOI: 10.1002/jwmg.625] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Adrienne L. Contasti
- Department of Biology; University of Saskatchewan; 112 Science Place Saskatoon SK, Canada S7N 5E2
| | - Floris M. Van Beest
- Department of Animal and Poultry Science; College of Agriculture and Bioresources; University of Saskatchewan; 51 Campus Drive Saskatoon SK, Canada S7N 5E2
| | - Eric Vander Wal
- Département de Biologie; Université de Sherbrooke; 2500 Boul de l'Université Sherbrooke QC, Canada J1K 2R1
| | - Philip D. Mcloughlin
- Department of Biology; University of Saskatchewan; 112 Science Place Saskatoon SK, Canada S7N 5E2
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Doxa A, Besnard A, Bechet A, Pin C, Lebreton JD, Sadoul N. Inferring dispersal dynamics from local population demographic modelling: the case of the slender-billed gull in France. Anim Conserv 2013. [DOI: 10.1111/acv.12048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Doxa
- Centre d'Ecologie Fonctionnelle et Evolutive (UMR 5175), Ecole Pratique des Hautes Etudes, Biogéographie et Ecologie des Vertébrés, campus CNRS; Montpellier Cedex 5 France
| | - A. Besnard
- Centre d'Ecologie Fonctionnelle et Evolutive (UMR 5175), Ecole Pratique des Hautes Etudes, Biogéographie et Ecologie des Vertébrés, campus CNRS; Montpellier Cedex 5 France
| | - A. Bechet
- Centre de Recherche de la Tour du Valat; Arles France
| | - C. Pin
- Les Amis des Marais du Vigueirat; Arles France
| | - J.-D. Lebreton
- Centre d'Ecologie Fonctionnelle et Evolutive (UMR 5175), campus CNRS; Montpellier Cedex 5 France
| | - N. Sadoul
- Les Amis des Marais du Vigueirat; Arles France
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Wilson HM, Flint PL, Powell AN, Grand JB, Moran CL. Population ecology of breeding Pacific common eiders on the Yukon-Kuskokwim Delta, Alaska. WILDLIFE MONOGRAPHS 2012. [DOI: 10.1002/wmon.8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Peery MZ, Kirby R, Reid BN, Stoelting R, Doucet-Bëer E, Robinson S, Vásquez-Carrillo C, Pauli JN, Palsbøll PJ. Reliability of genetic bottleneck tests for detecting recent population declines. Mol Ecol 2012; 21:3403-18. [PMID: 22646281 DOI: 10.1111/j.1365-294x.2012.05635.x] [Citation(s) in RCA: 312] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The identification of population bottlenecks is critical in conservation because populations that have experienced significant reductions in abundance are subject to a variety of genetic and demographic processes that can hasten extinction. Genetic bottleneck tests constitute an appealing and popular approach for determining if a population decline has occurred because they only require sampling at a single point in time, yet reflect demographic history over multiple generations. However, a review of the published literature indicates that, as typically applied, microsatellite-based bottleneck tests often do not detect bottlenecks in vertebrate populations known to have experienced declines. This observation was supported by simulations that revealed that bottleneck tests can have limited statistical power to detect bottlenecks largely as a result of limited sample sizes typically used in published studies. Moreover, commonly assumed values for mutation model parameters do not appear to encompass variation in microsatellite evolution observed in vertebrates and, on average, the proportion of multi-step mutations is underestimated by a factor of approximately two. As a result, bottleneck tests can have a higher probability of 'detecting' bottlenecks in stable populations than expected based on the nominal significance level. We provide recommendations that could add rigor to inferences drawn from future bottleneck tests and highlight new directions for the characterization of demographic history.
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Affiliation(s)
- M Zachariah Peery
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA.
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25
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Bentzen RL, Powell AN. Population dynamics of king eiders breeding in northern Alaska. J Wildl Manage 2012. [DOI: 10.1002/jwmg.335] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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26
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Donker SA, Krebs CJ. Evidence for source - sink dynamics in a regional population of arctic ground squirrels (Urocitellus parryii plesius). WILDLIFE RESEARCH 2012. [DOI: 10.1071/wr11167] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Variable demographic rates can manifest themselves between habitat types in the form of source–sink dynamics where populations in sink habitats would not exist without the addition of migrants from source habitats.
Aims
Arctic ground squirrels (Urocitellus parryii pleisus (Osgood, 1900)) occupy a large geographic area in northern Canada and live in a variety of habitat types, including boreal forest, low-elevation meadows and alpine meadows, providing an opportunity to investigate the possible existence of source–sink dynamics.
Methods
We hypothesised that arctic ground squirrels in the south-western Yukon exhibit demographic characteristics indicative of source–sink dynamics. Boreal forest habitat could be a sink in spite of previous high squirrel densities, whereas meadows could be a source. We investigated this by mark–recapture live-trapping and radio-telemetry.
Key Results
In the boreal forest in the Kluane region, we found reduced recruitment, reduced population growth rates (λ), and reduced survivorship for radio-collared individuals that moved from low-elevation meadows into the boreal forest. There was no evidence from radio-collared juveniles of dispersal from high-density ground squirrel populations in alpine meadows down into boreal forest.
Conclusions
Boreal forest is a sink habitat for arctic ground squirrels. Source–sink dynamics observed between low-elevation meadow and boreal forest habitats appear to result from increased predation pressure in the boreal forest. The result has been a near extirpation of boreal forest arctic ground squirrels in the Kluane region since 1998.
Implications
Because the source areas of low-elevation meadows occupy only 7–9% of the lowland habitat, recolonisation of boreal forest sites has been very slow. Whereas alpine populations remain high in 2011, boreal forest populations remain near zero. Alpine populations do not appear to be a source for the boreal forest.
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OOSTHUIZEN WCHRIS, DE BRUYN PJNICO, BESTER MARTHÁNN. Unmarked individuals in mark-recapture studies: Comparisons of marked and unmarked southern elephant seals at Marion Island. AUSTRAL ECOL 2011. [DOI: 10.1111/j.1442-9993.2011.02316.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Maranto CJ, Parrish JK, Herman DP, Punt AE, Olden JD, Brett MT, Roby DD. Use of fatty acid analysis to determine dispersal of caspian terns in the Columbia River Basin, USA. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2011; 25:736-746. [PMID: 21771078 DOI: 10.1111/j.1523-1739.2011.01706.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Lethal control, which has been used to reduce local abundances of animals in conflict with humans or with endangered species, may not achieve management goals if animal movement is not considered. In populations with emigration and immigration, lethal control may induce compensatory immigration, if the source of attraction remains unchanged. Within the Columbia River Basin (Washington, U.S.A.), avian predators forage at dams because dams tend to reduce rates of emigration of juvenile salmonids (Oncorhynchus spp.), artificially concentrating these prey. We used differences in fatty acid profiles between Caspian Terns (Hydroprogne caspia) at coastal and inland breeding colonies and terns culled by a lethal control program at a mid-Columbia River dam to infer dispersal patterns. We modeled the rate of loss of fatty acid biomarkers, which are fatty acids that can be traced to a single prey species or groups of species, to infer whether and when terns foraging at dams had emigrated from the coast. Nonmetric multidimensional scaling showed that coastal terns had high levels of C(20) and C(22) monounsaturated fatty acids, whereas fatty acids of inland breeders were high in C18:3n3, C20:4n6, and C22:5n3. Models of the rate of loss of fatty acid showed that approximately 60% of the terns collected at Rock Island Dam were unlikely to have bred successfully at local (inland) sites, suggesting that terns foraging at dams come from an extensive area. Fatty acid biomarkers may provide accurate information about patterns of dispersal in animal populations and may be extremely valuable in cases where populations differ demonstrably in prey base.
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Sepulveda AJ, Lowe WH. Coexistence in streams: do source-sink dynamics allow salamanders to persist with fish predators? Oecologia 2011; 166:1043-54. [PMID: 21347800 DOI: 10.1007/s00442-011-1935-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 02/01/2011] [Indexed: 10/18/2022]
Abstract
Theory suggests that source-sink dynamics can allow coexistence of intraguild predators and prey, but empirical evidence for this coexistence mechanism is limited. We used capture-mark-recapture, genetic methods, and stable isotopes to test whether source-sink dynamics promote coexistence between stream fishes, the intraguild predator, and stream salamanders (Dicamptodon aterrimus), the intraguild prey. Salamander populations from upstream reaches without fish were predicted to maintain or supplement sink populations in downstream reaches with fish. We found instead that downstream reaches with fish were not sinks even though fish consumed salamander larvae-apparent survival, recruitment, and population growth rate did not differ between upstream and downstream reaches. There was also no difference between upstream and downstream reaches in net emigration. We did find that D. aterrimus moved frequently along streams, but believe that this is a response to seasonal habitat changes rather than intraguild predation. Our study provides empirical evidence that local-scale mechanisms are more important than dispersal dynamics to coexistence of streams salamanders and fish. More broadly, it shows the value of empirical data on dispersal and gene flow for distinguishing between local and spatial mechanisms of coexistence.
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Affiliation(s)
- Adam J Sepulveda
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA.
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Pakanen VM, Rönkä A, Belda EJ, Luukkonen A, Kvist L, Koivula K. Impact of dispersal status on estimates of local population growth rates in a Temminck's stint Calidris temminckii population. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2010.18320.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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31
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Scoble J, Lowe AJ. A case for incorporating phylogeography and landscape genetics into species distribution modelling approaches to improve climate adaptation and conservation planning. DIVERS DISTRIB 2010. [DOI: 10.1111/j.1472-4642.2010.00658.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Abadi F, Gimenez O, Ullrich B, Arlettaz R, Schaub M. Estimation of immigration rate using integrated population models. J Appl Ecol 2010. [DOI: 10.1111/j.1365-2664.2010.01789.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Peery MZ, Hall LA, Sellas A, Beissinger SR, Moritz C, Bérubé M, Raphael MG, Nelson SK, Golightly RT, McFarlane-Tranquilla L, Newman S, Palsbøll PJ. Genetic analyses of historic and modern marbled murrelets suggest decoupling of migration and gene flow after habitat fragmentation. Proc Biol Sci 2010; 277:697-706. [PMID: 19906669 PMCID: PMC2842750 DOI: 10.1098/rspb.2009.1666] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 10/19/2009] [Indexed: 11/12/2022] Open
Abstract
The dispersal of individuals among fragmented populations is generally thought to prevent genetic and demographic isolation, and ultimately reduce extinction risk. In this study, we show that a century of reduction in coastal old-growth forests, as well as a number of other environmental factors, has probably resulted in the genetic divergence of marbled murrelets (Brachyramphus marmoratus) in central California, despite the fact that 7 per cent of modern-sampled murrelets in this population were classified as migrants using genetic assignment tests. Genetic differentiation appears to persist because individuals dispersing from northern populations contributed relatively few young to the central California population, as indicated by the fact that migrants were much less likely to be members of parent-offspring pairs than residents (10.5% versus 45.4%). Moreover, a recent 1.4 per cent annual increase in the proportion of migrants in central California, without appreciable reproduction, may have masked an underlying decline in the resident population without resulting in demographic rescue. Our results emphasize the need to understand the behaviour of migrants and the extent to which they contribute offspring in order to determine whether dispersal results in gene flow and prevents declines in resident populations.
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Affiliation(s)
- M Zachariah Peery
- Department of Forest and Wildlife Ecology, 1630 Linden Drive Madison, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Cooley HS, Wielgus RB, Koehler GM, Robinson HS, Maletzke BT. Does hunting regulate cougar populations? A test of the compensatory mortality hypothesis. Ecology 2009; 90:2913-21. [PMID: 19886499 DOI: 10.1890/08-1805.1] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Many wildlife species are managed based on the compensatory mortality hypothesis, which predicts that harvest mortality (especially adult male mortality) will trigger density-dependent responses in reproduction, survival, and population growth caused via reduced competition for resources. We tested the compensatory mortality hypothesis on two cougar (Puma concolor) populations in Washington, USA (one heavily hunted and one lightly hunted). We estimated population growth, density, survival, and reproduction to determine the effects of hunting on cougar population demography based on data collected from 2002 to 2007. In the heavily hunted population, the total hunting mortality rate (mean +/- SD) was 0.24 +/- 0.05 (0.35 +/- 0.08 for males, 0.16 +/- 0.05 for females). In the lightly hunted population, the total hunting mortality rate was 0.11 +/- 0.04 (0.16 +/- 0.06 for males, 0.07 +/- 0.05 for females). The compensatory mortality hypothesis predicts that higher mortality will result in higher maternity, kitten survival, reproductive success, and lower natural mortality. We found no differences in rates of maternity or natural mortality between study areas, and kitten survival was lower in the heavily hunted population. We rejected the compensatory mortality hypothesis because vital rates did not compensate for hunting mortality. Heavy harvest corresponded with increased immigration, reduced kitten survival, reduced female population growth, and a younger overall age structure. Light harvest corresponded with increased emigration, higher kitten survival, increased female population growth, and an older overall age structure. Managers should not assume the existence of compensatory mortality when developing harvest prescriptions for cougars.
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Affiliation(s)
- Hilary S Cooley
- Large Carnivore Conservation Laboratory, Department of Natural Resource Sciences, Washington State University, Pullman, Washington 99164-6410, USA.
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Hall LA, Palsbøll PJ, Beissinger SR, Harvey JT, Bérubé M, Raphael MG, Nelson SK, Golightly RT, McFarlane-Tranquilla L, Newman SH, Peery MZ. Characterizing dispersal patterns in a threatened seabird with limited genetic structure. Mol Ecol 2009; 18:5074-85. [PMID: 19912540 DOI: 10.1111/j.1365-294x.2009.04416.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Genetic assignment methods provide an appealing approach for characterizing dispersal patterns on ecological time scales, but require sufficient genetic differentiation to accurately identify migrants and a large enough sample size of migrants to, for example, compare dispersal between sexes or age classes. We demonstrate that assignment methods can be rigorously used to characterize dispersal patterns in a marbled murrelet (Brachyramphus marmoratus) population from central California that numbers approximately 600 individuals and is only moderately differentiated (F(ST) approximately 0.03) from larger populations to the north. We used coalescent simulations to select a significance level that resulted in a low and approximately equal expected number of type I and II errors and then used this significance level to identify a population of origin for 589 individuals genotyped at 13 microsatellite loci. The proportion of migrants in central California was greatest during winter when 83% of individuals were classified as migrants compared to lower proportions during the breeding (6%) and post-breeding (8%) seasons. Dispersal was also biased toward young and female individuals, as is typical in birds. Migrants were rarely members of parent-offspring pairs, suggesting that they contributed few young to the central California population. A greater number of migrants than expected under equilibrium conditions, a lack of individuals with mixed ancestry, and a small number of potential source populations (two), likely allowed us to use assignment methods to rigorously characterize dispersal patterns for a population that was larger and less differentiated than typically thought required for the identification of migrants.
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Cooley HS, Wielgus RB, Koehler G, Maletzke B. Source populations in carnivore management: cougar demography and emigration in a lightly hunted population. Anim Conserv 2009. [DOI: 10.1111/j.1469-1795.2009.00256.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Peery MZ, Beissinger SR, House RF, Bérubé M, Hall LA, Sellas A, Palsbøll PJ. Characterizing source-sink dynamics with genetic parentage assignments. Ecology 2009; 89:2746-59. [PMID: 18959312 DOI: 10.1890/07-2026.1] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Source-sink dynamics have been suggested to characterize the population structure of many species, but the prevalence of source-sink systems in nature is uncertain because of inherent challenges in estimating migration rates among populations. Migration rates are often difficult to estimate directly with demographic methods, and indirect genetic methods are subject to a variety of assumptions that are difficult to meet or to apply to evolutionary timescales. Furthermore, such methods cannot be rigorously applied to high-gene-flow species. Here, we employ genetic parentage assignments in conjunction with demographic simulations to infer the level of immigration into a putative sink population. We use individual-based demographic models to estimate expected distributions of parent-offspring dyads under competing sink and closed-population models. By comparing the actual number of parent-offspring dyads (identified from multilocus genetic profiles) in a random sample of individuals taken from a population to expectations under these two contrasting demographic models, it is possible to estimate the rate of immigration and test hypotheses related to the role of immigration on population processes on an ecological timescale. The difference in the expected number of parent-offspring dyads between the two population models was greatest when immigration into the sink population was high, indicating that unlike traditional population genetic inference models, the highest degree of statistical power is achieved for the approach presented here when migration rates are high. We used the proposed genetic parentage approach to demonstrate that a threatened population of Marbled Murrelets (Braclhyrarmphus marmotus) appears to be supplemented by a low level of immigration (approximately 2-6% annually) from other populations.
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Affiliation(s)
- M Zachariah Peery
- Department of Environmental Science, Policy and Management, 137 Mulfiord Hall, University of California, Berkeley, California 94720-3114, USA.
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Robinson HS, Wielgus RB, Cooley HS, Cooley SW. Sink populations in carnivore management: cougar demography and immigration in a hunted population. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2008; 18:1028-1037. [PMID: 18536260 DOI: 10.1890/07-0352.1] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Carnivores are widely hunted for both sport and population control, especially where they conflict with human interests. It is widely believed that sport hunting is effective in reducing carnivore populations and related human-carnivore conflicts, while maintaining viable populations. However, the way in which carnivore populations respond to harvest can vary greatly depending on their social structure, reproductive strategies, and dispersal patterns. For example, hunted cougar (Puma concolor) populations have shown a great degree of resiliency. Although hunting cougars on a broad geographic scale (> 2000 km2) has reduced densities, hunting of smaller areas (i.e., game management units, < 1000 km2), could conceivably fail because of increased immigration from adjacent source areas. We monitored a heavily hunted population from 2001 to 2006 to test for the effects of hunting at a small scale (< 1000 km2) and to gauge whether population control was achieved (lambda < or = 1.0) or if hunting losses were negated by increased immigration allowing the population to remain stable or increase (lambda > or = 1.0). The observed growth rate of 1.00 was significantly higher than our predicted survival/fecundity growth rates (using a Leslie matrix) of 0.89 (deterministic) and 0.84 (stochastic), with the difference representing an 11-16% annual immigration rate. We observed no decline in density of the total population or the adult population, but a significant decrease in the average age of independent males. We found that the male component of the population was increasing (observed male population growth rate, lambda(OM) = 1.09), masking a decrease in the female component (lambda(OF) = 0.91). Our data support the compensatory immigration sink hypothesis; cougar removal in small game management areas (< 1000 km2) increased immigration and recruitment of younger animals from adjacent areas, resulting in little or no reduction in local cougar densities and a shift in population structure toward younger animals. Hunting in high-quality habitats may create an attractive sink, leading to misinterpretation of population trends and masking population declines in the sink and surrounding source areas.
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Affiliation(s)
- Hugh S Robinson
- Large Carnivore Conservation Laboratory, Department of Natural Resource Sciences, Washington State University, Pullman, Washington 99164-6410, USA.
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40
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PRADEL R, HENRY PY. Potential contributions of capture–recapture to the estimation of population growth rate in restoration projects. ECOSCIENCE 2007. [DOI: 10.2980/1195-6860(2007)14[432:pcoctt]2.0.co;2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Despite recent advances in population genetic theory and empirical research, the extent of genetic differentiation among natural populations of animals remains difficult to predict. We reviewed studies of geographic variation in mitochondrial DNA in seabirds to test the importance of various factors in generating population genetic and phylogeographic structure. The extent of population genetic and phylogeographic structure varies extensively among species. Species fragmented by land or ice invariably exhibit population genetic structure and most also have phylogeographic structure. However, many populations (26 of 37) display genetic structure in the absence of land, suggesting that other barriers to gene flow exist. In these populations, the extent of genetic structure is best explained by nonbreeding distribution: almost all species with two or more population-specific nonbreeding areas (or seasons) have phylogeographic structure, and all species that are resident at or near breeding colonies year-round have population genetic structure. Geographic distance between colonies and foraging range appeared to have a weak influence on the extent of population genetic structure, but little evidence was found for an effect of colony dispersion or population bottlenecks. In two species (Galapagos petrel, Pterodroma phaeopygia, and Xantus's murrelet, Synthliboramphus hypoleucus), population genetic structure, and even phylogeographic structure, exist in the absence of any recognizable physical or nonphysical barrier, suggesting that other selective or behavioural processes such as philopatry may limit gene flow. Retained ancestral variation may be masking barriers to dispersal in some species, especially at high latitudes. Allopatric speciation undoubtedly occurs in this group, but reproductive isolation also appears to have evolved through founder-induced speciation, and there is strong evidence that parapatric and sympatric speciation occur. While many questions remain unanswered, results of the present review should aid conservation efforts by enabling managers to predict the extent of population differentiation in species that have not yet been studied using molecular markers, and, thus, enable the identification of management units and evolutionary significant units for conservation.
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Affiliation(s)
- V L Friesen
- Department of Biology, Queen's University, Kingston, Ontario, Canada.
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Abstract
Reducing extinction risk for threatened species requires determining which demographic parameters are depressed and causing population declines. Museum collections may constitute a unique, underutilized resource for measuring demographic changes over long time periods using age-ratio analysis. We reconstruct the historic demography of a U.S. federally endangered seabird, the Marbled Murrelet (Brachyramphus marmoratus), from specimens collected approximately 100 years ago for comparison with predictions from comparative analyses and with results from contemporary field studies using both age-ratio analysis and conventional demographic estimators. Reproduction in the late 1800s and early 1900s matched predictions from comparative analysis, but was 8-9 times greater than contemporary estimates, whereas adult survival was unchanged. Historic reproductive rates would support stable populations, but contemporary levels should result in population declines. Contemporary demographic estimates derived from age-ratio analysis were similar to estimates from conventional estimators. Using museum specimens to reconstruct historic demography provides a unique approach to identify causes of decline and to set demographic benchmarks for recovery of endangered species that meet most assumptions of age-ratio analysis.
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Affiliation(s)
- Steven R Beissinger
- Department of Environmental Science, Policy and Management, 137 Mulford Hall, University of California, Berkeley, California 94720-3114, USA.
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