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Martin SA, Peterman WE, Lipps GJ, Gibbs HL. Inferring population connectivity in eastern massasauga rattlesnakes (Sistrurus catenatus) using landscape genetics. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2793. [PMID: 36482809 DOI: 10.1002/eap.2793] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 10/18/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
Assessing the environmental factors that influence the ability of a threatened species to move through a landscape can be used to identify conservation actions that connect isolated populations. However, direct observations of species' movement are often limited, making the development of alternate approaches necessary. Here we use landscape genetic analyses to assess the impact of landscape features on the movement of individuals between local populations of a threatened snake, the eastern massasauga rattlesnake (Sistrurus catenatus). We linked connectivity data with habitat information from two landscapes of similar size: a large region of unfragmented habitat and a previously studied fragmented landscape consisting of isolated patches of habitat. We used this analysis to identify features of the landscape where modification or acquisition would enhance population connectivity in the fragmented region. We found evidence that current connectivity was impacted by both contemporary land-cover features, especially roads, and inherent landscape features such as elevation. Next, we derived estimates of expected movement ability using a recently developed pedigree-based approach and least-cost paths through the unfragmented landscape. We then used our pedigree and resistance map to estimate resistance polygons of the potential extent for S. catenatus movement in the fragmented landscape. These polygons identify possible sites for future corridors connecting currently isolated populations in this landscape by linking the impact of future habitat modification or land acquisition to dispersal ability in this species. Overall, our study shows how modeling landscape resistance across differently fragmented landscapes can identify habitat features that affect contemporary movement in threatened species in fragmented landscapes and how this information can be used to guide mitigation actions whose goal is to connect isolated populations.
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Affiliation(s)
- Scott A Martin
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio, USA
- Ohio Biodiversity Conservation Partnership, The Ohio State University, Columbus, Ohio, USA
| | - William E Peterman
- Ohio Biodiversity Conservation Partnership, The Ohio State University, Columbus, Ohio, USA
- School of Environmental and Natural Resources, The Ohio State University, Columbus, Ohio, USA
| | - Gregory J Lipps
- Ohio Biodiversity Conservation Partnership, The Ohio State University, Columbus, Ohio, USA
| | - H Lisle Gibbs
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio, USA
- Ohio Biodiversity Conservation Partnership, The Ohio State University, Columbus, Ohio, USA
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2
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Blais BR, Wells SA, Poynter BM, Harris TR, Allard RA, Koprowski JL. Bridging conservation across the ex situ‐in situ spectrum: Insights into the reproductive ecology of the threatened narrow‐headed gartersnake (
Thamnophis rufipunctatus
). Zoo Biol 2022; 42:429-439. [DOI: 10.1002/zoo.21747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 10/28/2022] [Accepted: 12/03/2022] [Indexed: 12/24/2022]
Affiliation(s)
- Brian R. Blais
- School of Natural Resources and the Environment University of Arizona Tucson Arizona USA
| | - Stuart A. Wells
- School of Natural Resources and the Environment University of Arizona Tucson Arizona USA
- Department of Conservation and Science Arizona Center for Nature Conservation/Phoenix Zoo Phoenix Arizona USA
| | - Bradley M. Poynter
- Department of Conservation and Science Arizona Center for Nature Conservation/Phoenix Zoo Phoenix Arizona USA
| | - Tara R. Harris
- Department of Conservation and Science Arizona Center for Nature Conservation/Phoenix Zoo Phoenix Arizona USA
| | - Ruth A. Allard
- Department of Conservation and Science Arizona Center for Nature Conservation/Phoenix Zoo Phoenix Arizona USA
| | - John L. Koprowski
- School of Natural Resources and the Environment University of Arizona Tucson Arizona USA
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3
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Lettoof DC, Thomson VA, Cornelis J, Bateman PW, Aubret F, Gagnon MM, von Takach B. Bioindicator snake shows genomic signatures of natural and anthropogenic barriers to gene flow. PLoS One 2021; 16:e0259124. [PMID: 34714831 PMCID: PMC8555784 DOI: 10.1371/journal.pone.0259124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/12/2021] [Indexed: 11/18/2022] Open
Abstract
Urbanisation alters landscapes, introduces wildlife to novel stressors, and fragments habitats into remnant 'islands'. Within these islands, isolated wildlife populations can experience genetic drift and subsequently suffer from inbreeding depression and reduced adaptive potential. The Western tiger snake (Notechis scutatus occidentalis) is a predator of wetlands in the Swan Coastal Plain, a unique bioregion that has suffered substantial degradation through the development of the city of Perth, Western Australia. Within the urban matrix, tiger snakes now only persist in a handful of wetlands where they are known to bioaccumulate a suite of contaminants, and have recently been suggested as a relevant bioindicator of ecosystem health. Here, we used genome-wide single nucleotide polymorphism (SNP) data to explore the contemporary population genomics of seven tiger snake populations across the urban matrix. Specifically, we used population genomic structure and diversity, effective population sizes (Ne), and heterozygosity-fitness correlations to assess fitness of each population with respect to urbanisation. We found that population genomic structure was strongest across the northern and southern sides of a major river system, with the northern cluster of populations exhibiting lower heterozygosities than the southern cluster, likely due to a lack of historical gene flow. We also observed an increasing signal of inbreeding and genetic drift with increasing geographic isolation due to urbanisation. Effective population sizes (Ne) at most sites were small (< 100), with Ne appearing to reflect the area of available habitat rather than the degree of adjacent urbanisation. This suggests that ecosystem management and restoration may be the best method to buffer the further loss of genetic diversity in urban wetlands. If tiger snake populations continue to decline in urban areas, our results provide a baseline measure of genomic diversity, as well as highlighting which 'islands' of habitat are most in need of management and protection.
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Affiliation(s)
- Damian C. Lettoof
- Behavioural Ecology Lab, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Vicki A. Thomson
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Jari Cornelis
- Behavioural Ecology Lab, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Philip W. Bateman
- Behavioural Ecology Lab, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Fabien Aubret
- Station d’Ecologie Théorique et Expérimentale, CNRS, Moulis, France
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Marthe M. Gagnon
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Brenton von Takach
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
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4
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Ochoa A, Gibbs HL. Genomic signatures of inbreeding and mutation load in a threatened rattlesnake. Mol Ecol 2021; 30:5454-5469. [PMID: 34448259 DOI: 10.1111/mec.16147] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/04/2021] [Accepted: 08/16/2021] [Indexed: 11/28/2022]
Abstract
Theory predicts that threatened species living in small populations will experience high levels of inbreeding that will increase their genetic load, but recent work suggests that the impact of load may be minimized by purging resulting from long-term population bottlenecks. Empirical studies that examine this idea using genome-wide estimates of inbreeding and genetic load in threatened species are limited. Here we use individual genome resequencing data to compare levels of inbreeding, levels of genetic load (estimated as mutation load) and population history in threatened Eastern massasauga rattlesnakes (Sistrurus catenatus), which exist in small isolated populations, and closely related yet outbred Western massasauga rattlesnakes (Sistrurus tergeminus). In terms of inbreeding, S. catenatus genomes had a greater number of runs of homozygosity of varying sizes, indicating sustained inbreeding through repeated bottlenecks when compared to S. tergeminus. At the species level, outbred S. tergeminus had higher genome-wide levels of mutation load in the form of greater numbers of derived deleterious mutations compared to S. catenatus, presumably due to long-term purging of deleterious mutations in S. catenatus. In contrast, mutations that escaped species-level drift effects within S. catenatus populations were in general more frequent and more often found in homozygous genotypes than in S. tergeminus, suggesting a reduced efficiency of purifying selection in smaller S. catenatus populations for most mutations. Our results support an emerging idea that the historical demography of a threatened species has a significant impact on the type of genetic load present, which impacts implementation of conservation actions such as genetic rescue.
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Affiliation(s)
- Alexander Ochoa
- Department of Evolution, Ecology, and Organismal Biology, Ohio Biodiversity Conservation Partnership, Ohio State University, Columbus, Ohio, USA
| | - H Lisle Gibbs
- Department of Evolution, Ecology, and Organismal Biology, Ohio Biodiversity Conservation Partnership, Ohio State University, Columbus, Ohio, USA
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5
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Janecka MJ, Janecka JE, Haines AM, Michaels A, Criscione CD. Post-delisting genetic monitoring reveals population subdivision along river and reservoir localities of the endemic Concho water snake (Nerodia harteri paucimaculata). CONSERV GENET 2021. [DOI: 10.1007/s10592-021-01391-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Botero-Delgadillo E, Quirici V, Vásquez RA, Kempenaers B. Heterozygosity-Fitness Correlations in a Continental Island Population of Thorn-Tailed Rayadito. J Hered 2020; 111:628-639. [PMID: 33277658 DOI: 10.1093/jhered/esaa056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/04/2020] [Indexed: 11/15/2022] Open
Abstract
Heterozygosity-fitness correlations (HFCs) have been used to monitor the effects of inbreeding in threatened populations. HFCs can also be useful to investigate the potential effects of inbreeding in isolated relict populations of long-term persistence and to better understand the role of inbreeding and outbreeding as drivers of changes in genetic diversity. We studied a continental island population of thorn-tailed rayadito (Aphrastura spinicauda) inhabiting the relict forest of Fray Jorge National Park, north-central Chile. This population has experienced a long-term, gradual process of isolation since the end of the Tertiary. Using 10 years of field data in combination with molecular techniques, we tested for HFCs to assess the importance of inbreeding depression. If inbreeding depression is important, we predict a positive relationship between individual heterozygosity and fitness-related traits. We genotyped 183 individuals at 12 polymorphic microsatellite loci and used 7 measures of reproductive success and estimates of apparent survival to calculate HFCs. We found weak to moderate statistical support (P-values between 0.05 and 0.01) for a linear effect of female multi-locus heterozygosity (MLH) on clutch size and nonlinear effects on laying date and fledging success. While more heterozygous females laid smaller clutches, nonlinear effects indicated that females with intermediate values of MLH started laying earlier and had higher fledging success. We found no evidence for effects of MLH on annual fecundity or on apparent survival. Our results along with the long-term demographic stability of the study population contradict the hypothesis that inbreeding depression occurs in this population.
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Affiliation(s)
- Esteban Botero-Delgadillo
- Department of Behavioural Ecology and Evolutionary Genetics, Max Plank Institute for Ornithology, Seewiesen, Germany
| | - Verónica Quirici
- Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Santiago, Chile.,Centro de investigación para la sustentabilidad, Universidad Andrés Bello, Santiago, Chile
| | - Rodrigo A Vásquez
- Instituto de Ecología y Biodiversidad, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Bart Kempenaers
- Department of Behavioural Ecology and Evolutionary Genetics, Max Plank Institute for Ornithology, Seewiesen, Germany
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7
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Ochoa A, Broe M, Moriarty Lemmon E, Lemmon AR, Rokyta DR, Gibbs HL. Drift, selection and adaptive variation in small populations of a threatened rattlesnake. Mol Ecol 2020; 29:2612-2625. [PMID: 32557885 DOI: 10.1111/mec.15517] [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: 11/26/2019] [Revised: 05/09/2020] [Accepted: 05/21/2020] [Indexed: 01/22/2023]
Abstract
An important goal of conservation genetics is to determine if the viability of small populations is reduced by a loss of adaptive variation due to genetic drift. Here, we assessed the impact of drift and selection on direct measures of adaptive variation (toxin loci encoding venom proteins) in the eastern massasauga rattlesnake (Sistrurus catenatus), a threatened reptile that exists in small isolated populations. We estimated levels of individual polymorphism in 46 toxin loci and 1,467 control loci across 12 populations of this species, and compared the results with patterns of selection on the same loci following speciation of S. catenatus and its closest relative, the western massasauga (S. tergeminus). Multiple lines of evidence suggest that both drift and selection have had observable impacts on standing adaptive variation. In support of drift effects, we found little evidence for selection on toxin variation within populations and a significant positive relationship between current levels of adaptive variation and long- and short-term estimates of effective population size. However, we also observed levels of directional selection on toxin loci among populations that are broadly similar to patterns predicted from interspecific selection analyses that pre-date the effects of recent drift, and that functional variation in these loci persists despite small short-term effective sizes. This suggests that much of the adaptive variation present in populations may represent an example of "drift debt," a nonequilibrium state where present-day levels of variation overestimate the amount of functional genetic diversity present in future populations.
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Affiliation(s)
- Alexander Ochoa
- Ohio Biodiversity Conservation Partnership and Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, USA
| | - Michael Broe
- Ohio Biodiversity Conservation Partnership and Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, USA
| | | | - Alan R Lemmon
- Department of Scientific Computing, Florida State University, Tallahassee, FL, USA
| | - Darin R Rokyta
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - H Lisle Gibbs
- Ohio Biodiversity Conservation Partnership and Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, USA
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8
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Sovic M, Fries A, Martin SA, Lisle Gibbs H. Genetic signatures of small effective population sizes and demographic declines in an endangered rattlesnake, Sistrurus catenatus. Evol Appl 2019; 12:664-678. [PMID: 30976301 PMCID: PMC6439488 DOI: 10.1111/eva.12731] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 09/28/2018] [Accepted: 10/01/2018] [Indexed: 12/15/2022] Open
Abstract
Endangered species that exist in small isolated populations are at elevated risk of losing adaptive variation due to genetic drift. Analyses that estimate short-term effective population sizes, characterize historical demographic processes, and project the trajectory of genetic variation into the future are useful for predicting how levels of genetic diversity may change. Here, we use data from two independent types of genetic markers (single nucleotide polymorphisms [SNPs] and microsatellites) to evaluate genetic diversity in 17 populations spanning the geographic range of the endangered eastern massasauga rattlesnake (Sistrurus catenatus). First, we use SNP data to confirm previous reports that these populations exhibit high levels of genetic structure (overall Fst = 0.25). Second, we show that most populations have contemporary Ne estimates <50. Heterozygosity-fitness correlations in these populations provided no evidence for a genetic cost to living in small populations, though these tests may lack power. Third, model-based demographic analyses of individual populations indicate that all have experienced declines, with the onset of many of these declines occurring over timescales consistent with anthropogenic impacts (<200 years). Finally, forward simulations of the expected loss of variation in relatively large (Ne = 50) and small (Ne = 10) populations indicate they will lose a substantial amount of their current standing neutral variation (63% and 99%, respectively) over the next 100 years. Our results argue that drift has a significant and increasing impact on levels of genetic variation in isolated populations of this snake, and efforts to assess and mitigate associated impacts on adaptive variation should be components of the management of this endangered reptile.
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Affiliation(s)
- Michael Sovic
- Department of Evolution, Ecology and Organismal Biology and Ohio Biodiversity Conservation PartnershipThe Ohio State UniversityColumbusOhio
- Present address:
College of PharmacyThe Ohio State UniversityColumbusOhio
| | - Anthony Fries
- Department of Evolution, Ecology and Organismal Biology and Ohio Biodiversity Conservation PartnershipThe Ohio State UniversityColumbusOhio
- United States Air Force School of Aerospace MedicineWright‐Patterson AFBColumbusOhio
| | - Scott A. Martin
- Department of Evolution, Ecology and Organismal Biology and Ohio Biodiversity Conservation PartnershipThe Ohio State UniversityColumbusOhio
| | - H. Lisle Gibbs
- Department of Evolution, Ecology and Organismal Biology and Ohio Biodiversity Conservation PartnershipThe Ohio State UniversityColumbusOhio
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9
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Baker SJ, Anthonysamy WJB, Davis MA, Dreslik MJ, Douglas MR, Douglas ME, Phillips CA. Temporal Patterns of Genetic Diversity in an Imperiled Population of the Eastern Massasauga Rattlesnake (Sistrurus catenatus). COPEIA 2018. [DOI: 10.1643/cg-17-682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Oxidative stress in wild European rabbits naturally infected with myxoma virus and rabbit haemorrhagic disease virus. EUR J WILDLIFE RES 2018. [DOI: 10.1007/s10344-018-1203-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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11
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Demography of a Small and Isolated Population of Eastern Massasauga Rattlesnakes (Sistrurus catenatus) Threatened by Vegetative Succession. J HERPETOL 2016. [DOI: 10.1670/121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Jaeger CP, Duvall MR, Swanson BJ, Phillips CA, Dreslik MJ, Baker SJ, King RB. Microsatellite and major histocompatibility complex variation in an endangered rattlesnake, the Eastern Massasauga (Sistrurus catenatus). Ecol Evol 2016; 6:3991-4003. [PMID: 27516858 PMCID: PMC4874855 DOI: 10.1002/ece3.2159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 01/18/2023] Open
Abstract
Genetic diversity is fundamental to maintaining the long-term viability of populations, yet reduced genetic variation is often associated with small, isolated populations. To examine the relationship between demography and genetic variation, variation at hypervariable loci (e.g., microsatellite DNA loci) is often measured. However, these loci are selectively neutral (or near neutral) and may not accurately reflect genomewide variation. Variation at functional trait loci, such as the major histocompatibility complex (MHC), can provide a better assessment of adaptive genetic variation in fragmented populations. We compared patterns of microsatellite and MHC variation across three Eastern Massasauga (Sistrurus catenatus) populations representing a gradient of demographic histories to assess the relative roles of natural selection and genetic drift. Using 454 deep amplicon sequencing, we identified 24 putatively functional MHC IIB exon 2 alleles belonging to a minimum of six loci. Analysis of synonymous and nonsynonymous substitution rates provided evidence of historical positive selection at the nucleotide level, and Tajima's D provided support for balancing selection in each population. As predicted, estimates of microsatellite allelic richness, observed, heterozygosity, and expected heterozygosity varied among populations in a pattern qualitatively consistent with demographic history and abundance. While MHC allelic richness at the population and individual levels revealed similar trends, MHC nucleotide diversity was unexpectedly high in the smallest population. Overall, these results suggest that genetic variation in the Eastern Massasauga populations in Illinois has been shaped by multiple evolutionary mechanisms. Thus, conservation efforts should consider both neutral and functional genetic variation when managing captive and wild Eastern Massasauga populations.
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Affiliation(s)
- Collin P. Jaeger
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| | - Melvin R. Duvall
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| | - Bradley J. Swanson
- Department of BiologyCentral Michigan UniversityMt. PleasantMichigan48859
| | - Christopher A. Phillips
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Michael J. Dreslik
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Sarah J. Baker
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Richard B. King
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
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13
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Nell LA, Frederick PC, Mazzotti FJ, Vliet KA, Brandt LA. Presence of Breeding Birds Improves Body Condition for a Crocodilian Nest Protector. PLoS One 2016; 11:e0149572. [PMID: 26934602 PMCID: PMC4775066 DOI: 10.1371/journal.pone.0149572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/02/2016] [Indexed: 11/29/2022] Open
Abstract
Ecological associations where one species enhances habitat for another nearby species (facilitations) shape fundamental community dynamics and can promote niche expansion, thereby influencing how and where species persist and coexist. For the many breeding birds facing high nest-predation pressure, enemy-free space can be gained by nesting near more formidable animals for physical protection. While the benefits to protected species seem well documented, very few studies have explored whether and how protector species are affected by nest protection associations. Long-legged wading birds (Pelecaniformes and Ciconiiformes) actively choose nesting sites above resident American alligators (Alligator mississippiensis), apparently to take advantage of the protection from mammalian nest predators that alligator presence offers. Previous research has shown that wading bird nesting colonies could provide substantial food for alligators in the form of dropped chicks. We compared alligator body condition in similar habitat with and without wading bird nesting colonies present. Alligator morphometric body condition indices were significantly higher in colony than in non-colony locations, an effect that was statistically independent of a range of environmental variables. Since colonially nesting birds and crocodilians co-occur in many tropical and subtropical wetlands, our results highlight a potentially widespread keystone process between two ecologically important species-groups. These findings suggest the interaction is highly beneficial for both groups of actors, and illustrate how selective pressures may have acted to form and reinforce a strongly positive ecological interaction.
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Affiliation(s)
- Lucas A. Nell
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
| | - Peter C. Frederick
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, Florida, United States of America
| | - Frank J. Mazzotti
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Kent A. Vliet
- Department of Biology, University of Florida, Gainesville, Florida, United States of America
| | - Laura A. Brandt
- United States Fish and Wildlife Service, Davie, Florida, United States of America
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Reynolds RG, Puente-Rolón AR, Platenberg R, Tyler RK, Tolson PJ, Revell LJ. Large divergence and low diversity suggest genetically informed conservation strategies for the endangered Virgin Islands Boa (Chilabothrus monensis). Glob Ecol Conserv 2015. [DOI: 10.1016/j.gecco.2015.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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