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Summers J, Cosgrove EJ, Bowman R, Fitzpatrick JW, Chen N. Impacts of increasing isolation and environmental variation on Florida Scrub-Jay demography. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.575127. [PMID: 38260596 PMCID: PMC10802623 DOI: 10.1101/2024.01.10.575127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Isolation caused by anthropogenic habitat fragmentation can destabilize populations. Populations relying on the inflow of immigrants can face reduced fitness due to inbreeding depression as fewer new individuals arrive. Empirical studies of the demographic consequences of isolation are critical to understand how populations persist through changing conditions. We used a 34-year demographic and environmental dataset from a population of cooperatively-breeding Florida Scrub-Jays ( Aphelocoma coerulescens ) to create mechanistic models linking environmental and demographic factors to population growth rates. We found that the population has not declined despite both declining immigration and increasing inbreeding, owing to a coinciding response in breeder survival. We find evidence of density-dependent immigration, breeder survival, and fecundity, indicating that interactions between vital rates and local density play a role in buffering the population against change. Our study elucidates the impacts of isolation on demography and how long-term stability is maintained via demographic responses.
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Rutherford KL, Cottenie K, Denomme-Brown ST. To go or not to go: variable density-dependent dispersal in small mammals. J Mammal 2022. [DOI: 10.1093/jmammal/gyac117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Abstract
Population density has been widely understood to be a key influencer of dispersal behavior; however, the generality of density-dependent (DD) dispersal in vertebrates is unclear. We conducted a review of the available empirical data on small mammal DD dispersal, distinguishing between the three dispersal stages: emigration, immigration, and transience (dispersal distance). We focused on small mammals because they are a well-studied, functionally similar group of vertebrates, with a distinct ecological importance. We also examined the effect of season, body mass, study length, and study type on the strength and direction of DD dispersal. The majority of emigration and dispersal distance studies reported negative density dependence, while immigration was mostly independent of density. No correlative patterns were detected; however, interpretation of the available data was hindered by inconsistencies in experimental and analytical approach across studies. Our results suggest that the three phases of the dispersal process may be influenced differently by density and highlight the importance of distinguishing between emigration, immigration, and transience when considering the effects of density dependence. As well, our study identifies several limitations with the current available data which limit the ability to compare DD dispersal behavior across systems, and calls for future investigations that consider all three phases of dispersal in the same system.
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Affiliation(s)
- Kate L Rutherford
- Department of Integrative Biology, University of Guelph , 50 Stone Road East, Guelph, Ontario N1G 2W1 , Canada
| | - Karl Cottenie
- Department of Integrative Biology, University of Guelph , 50 Stone Road East, Guelph, Ontario N1G 2W1 , Canada
| | - Simon T Denomme-Brown
- Department of Integrative Biology, University of Guelph , 50 Stone Road East, Guelph, Ontario N1G 2W1 , Canada
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Weegman MD, Alisauskas RT, Kellett DK, Zhao Q, Wilson S, Telenský T. Local population collapse of Ross's and lesser snow geese driven by failing recruitment and diminished philopatry. OIKOS 2022. [DOI: 10.1111/oik.09184] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mitch D. Weegman
- School of Natural Resources, Univ. of Missouri Columbia MO USA
- Dept of Biology, Univ. of Saskatchewan Saskatoon SK Canada
| | - Ray T. Alisauskas
- Dept of Biology, Univ. of Saskatchewan Saskatoon SK Canada
- Science and Technology Branch, Prairie and Northern Wildlife Research Centre, Environment and Climate Change Canada Saskatoon SK Canada
| | - Dana K. Kellett
- Dept of Biology, Univ. of Saskatchewan Saskatoon SK Canada
- Science and Technology Branch, Prairie and Northern Wildlife Research Centre, Environment and Climate Change Canada Saskatoon SK Canada
| | - Qing Zhao
- School of Natural Resources, Univ. of Missouri Columbia MO USA
- Bird Conservancy of the Rockies Fort Collins CO USA
| | - Scott Wilson
- Science and Technology Branch, Pacific Wildlife Research Centre, Environment and Climate Change Canada Delta BC Canada
- Dept of Forest and Conservation Sciences, Univ. of British Columbia Vancouver BC Canada
| | - Tomáš Telenský
- Inst. for Environmental Studies, Faculty of Science, Charles Univ. Prague Czech Republic
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Czuppon P, Blanquart F, Uecker H, Débarre F. The Effect of Habitat Choice on Evolutionary Rescue in Subdivided Populations. Am Nat 2021; 197:625-643. [PMID: 33989144 DOI: 10.1086/714034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractEvolutionary rescue is the process by which a population, in response to an environmental change, successfully avoids extinction through adaptation. In spatially structured environments, dispersal can affect the probability of rescue. Here, we model an environment consisting of patches that degrade one after another, and we investigate the probability of rescue by a mutant adapted to the degraded habitat. We focus on the effects of dispersal and of immigration biases. We identify up to three regions delimiting the effect of dispersal on the probability of evolutionary rescue: (i) starting from low dispersal rates, the probability of rescue increases with dispersal; (ii) at intermediate dispersal rates, it decreases; and (iii) at large dispersal rates, it increases again with dispersal, except if mutants are too counterselected in not-yet-degraded patches. The probability of rescue is generally highest when mutant and wild-type individuals preferentially immigrate into patches that have already undergone environmental change. Additionally, we find that mutants that will eventually rescue the population most likely first appear in nondegraded patches. Overall, our results show that habitat choice, compared with the often-studied unbiased immigration scheme, can substantially alter the dynamics of population survival and adaptation to new environments.
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Reichert BE, Fletcher RJ, Kitchens WM. The demographic contributions of connectivity versus local dynamics to population growth of an endangered bird. J Anim Ecol 2020; 90:574-584. [PMID: 33179773 DOI: 10.1111/1365-2656.13387] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 10/07/2020] [Indexed: 11/30/2022]
Abstract
Conservation and management increasingly focus on connectivity, because connectivity driven by variation in immigration rates across landscapes is thought to be crucial for maintaining local population and metapopulation persistence. Yet, efforts to quantify the relative role of immigration on population growth across the entire range of species and over time have been lacking. We assessed whether immigration limited local and range-wide population growth of the endangered snail kite Rostrhamus sociabilis in Florida, USA, over 18 years using multi-state, reverse-time modelling that accounts for imperfect detection of individuals and unobservable states. Demographic contributions of immigration varied depending on the dynamics and geographic position of the local populations, were scale-dependent and changed over time. By comparing the relative contributions of immigration versus local demography for periods of significant change in local abundance, we found empirical evidence for a disproportionately large role of immigration in facilitating population growth of a centrally located population-a connectivity 'hub'. The importance of connectivity changed depending of the spatial scale considered, such that immigration was a more important driver of population growth at small versus large spatial scales. Furthermore, the contribution of immigration was much greater during time periods when local population size was small, emphasizing abundance-dependent rescue effects. Our findings suggest that efforts aimed at improving local breeding habitat will likely be most effective at increasing snail kite population growth. More broadly, our results provide much needed information on the role of connectivity for population growth, suggesting that connectivity conservation may have the greatest benefits when efforts focus on centrally located habitat patches and small populations. Furthermore, our results highlight that connectivity is highly dynamic over time and that interpreting the effects of connectivity at local scales may not transfer to region-wide dynamics.
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Affiliation(s)
- Brian E Reichert
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Robert J Fletcher
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Wiley M Kitchens
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
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Yeiser JM, Jackson AL, Sisson DC, Terhune TM, Martin JA. Predation Management and Spatial Structure Moderate Extirpation Risk and Harvest of Northern Bobwhite. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- John M. Yeiser
- D. B. Warnell School of Forestry and Natural Resources University of Georgia Athens GA 30602 USA
| | - Alexander L. Jackson
- D. B. Warnell School of Forestry and Natural Resources University of Georgia Athens GA 30602 USA
| | - D. Clay Sisson
- Tall Timbers, Albany Quail Project 5765 Pigeon Road Newton GA 39870 USA
| | | | - James A. Martin
- D. B. Warnell School of Forestry and Natural Resources University of Georgia Athens GA 30602 USA
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Nadal J, Ponz C, Comas C, Margalida A. Time, geography and weather provide insights into the ecological strategy of a migrant species. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 649:1096-1104. [PMID: 30308881 DOI: 10.1016/j.scitotenv.2018.08.345] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 08/24/2018] [Accepted: 08/25/2018] [Indexed: 06/08/2023]
Abstract
Farmland and migratory bird populations are in decline. The Common quail (Coturnix coturnix) provides an exception to this trend and its populations have remained stable over the last two decades. However, some basic facts regarding quail biology and ecology, such as the geographic distribution of age and sex classes during the summer, remain poorly understood. We analyzed 43,194 Spanish quail ringing records from 1961 to 2014 to assess the effects of geography and weather conditions on the probability that individuals will be ringed during the various stages of their annual cycle (arrival -spring migration-, stationary breeding period, departure -autumn migration- and winter) for the different quail age-sex classes over time. We found that spatial distribution of the age and sex classes can be explained by date, latitude, longitude, altitude, rainfall, and temperature. Our results suggest that date accounts for most of the variation in the distribution of quail age classes, followed by the weather variables, and then latitude, and altitude. Similarly, date also accounts for most of the variation in the distribution of the two sexes. These results could partially explain why this species has avoided population decline, since its ecological strategy is based on its temporal and spatial distribution combined with the segregation of age and sex groups. We hypothesize that the distribution of quail age and sex classes follows variations in weather and habitat suitability to exploit seasonal and geographic variations in resource availability. The migratory and nomadic movements of quail, combined with the occurrence of multiple breeding attempts within a single season, may also allow these birds to overcome the impacts of predators and anthropogenic environmental change. Conservation and management efforts should therefore take account of these age and sex related temporal and spatial patterns.
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Affiliation(s)
- Jesús Nadal
- Department of Animal Science, Division of Wildlife, Faculty of Life Sciences and Engineering, University of Lleida, 25198 Lleida, Spain.
| | - Carolina Ponz
- Department of Animal Science, Division of Wildlife, Faculty of Life Sciences and Engineering, University of Lleida, 25198 Lleida, Spain
| | - Carles Comas
- Department of Mathematics, Agrotecnio Center, University of Lleida, 25001 Lleida, Spain
| | - Antoni Margalida
- Department of Animal Science, Division of Wildlife, Faculty of Life Sciences and Engineering, University of Lleida, 25198 Lleida, Spain; Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland; Institute for Game and Wildlife Research, IREC (CSIC.UCLM-JCCM), 13005 Ciudad Real, Spain
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8
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Maag N, Cozzi G, Clutton-Brock T, Ozgul A. Density-dependent dispersal strategies in a cooperative breeder. Ecology 2018; 99:1932-1941. [DOI: 10.1002/ecy.2433] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 05/31/2018] [Accepted: 06/11/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Nino Maag
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 Zurich CH-8057 Switzerland
- Kalahari Research Centre; Kuruman River Reserve Van Zylsrus 8467 South Africa
| | - Gabriele Cozzi
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 Zurich CH-8057 Switzerland
- Kalahari Research Centre; Kuruman River Reserve Van Zylsrus 8467 South Africa
| | - Tim Clutton-Brock
- Kalahari Research Centre; Kuruman River Reserve Van Zylsrus 8467 South Africa
- Department of Zoology; University of Cambridge; Downing Street Cambridge CB2 3EJ United Kingdom
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 Zurich CH-8057 Switzerland
- Kalahari Research Centre; Kuruman River Reserve Van Zylsrus 8467 South Africa
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Wilson S, Saracco JF, Krikun R, Flockhart DTT, Godwin CM, Foster KR. Drivers of demographic decline across the annual cycle of a threatened migratory bird. Sci Rep 2018; 8:7316. [PMID: 29743651 PMCID: PMC5943453 DOI: 10.1038/s41598-018-25633-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/18/2018] [Indexed: 02/07/2023] Open
Abstract
Migratory species are rapidly declining but we rarely know which periods of the annual cycle are limiting for most species. This knowledge is needed to effectively allocate conservation resources to the periods of the annual cycle that best promote species recovery. We examined demographic trends and response to human footprint for Canada warblers (Cardellina canadensis), a threatened Neotropical migrant, using range-wide data (1993–2016) from the Monitoring Avian Productivity and Survivorship (MAPS) program on the breeding grounds. Declines in abundance were steepest in the eastern breeding region, followed by the western region. Breeding productivity did not decline in any region. In contrast, we observed declining recruitment in all regions, low apparent survival in the east and west, and a decline in apparent survival in the east. Abundance declined with increasing disturbance around MAPS stations. Between 1993 and 2009, the human footprint index on the breeding range increased by 0.11% in contrast to a 14% increase on the wintering range. Landscape-scale disturbance on the breeding grounds may influence abundance in some regions; however, the observed trends in demography and footprint suggests limitation during the non-breeding period as the likely driver of overall declines, particularly for eastern populations.
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Affiliation(s)
- Scott Wilson
- Wildlife Research Division, Environment Canada, National Wildlife Research Centre, 1125 Colonel by Drive, Ottawa, ON, K1A 0H3, Canada.
| | - James F Saracco
- The Institute for Bird Populations, PO Box 1346, Point Reyes Station, CA, 94956, USA
| | - Richard Krikun
- Lesser Slave Lake Bird Observatory, Box 1076, Slave Lake, AB, T0G2A0, Canada
| | - D T Tyler Flockhart
- Lesser Slave Lake Bird Observatory, Box 1076, Slave Lake, AB, T0G2A0, Canada.,University of Maryland Center for Environmental Science, Appalachian Laboratory, 301 Braddock Road, Frostburg, MD, 21532, USA
| | - Christine M Godwin
- Owl Moon Environmental Inc., 324 Killdeer Way, Fort McMurray, Alberta, T9K 0R3, Canada
| | - Kenneth R Foster
- Owl Moon Environmental Inc., 324 Killdeer Way, Fort McMurray, Alberta, T9K 0R3, Canada
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