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Rolls RJ, Deane DC, Johnson SE, Heino J, Anderson MJ, Ellingsen KE. Biotic homogenisation and differentiation as directional change in beta diversity: synthesising driver-response relationships to develop conceptual models across ecosystems. Biol Rev Camb Philos Soc 2023; 98:1388-1423. [PMID: 37072381 DOI: 10.1111/brv.12958] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 04/20/2023]
Abstract
Biotic homogenisation is defined as decreasing dissimilarity among ecological assemblages sampled within a given spatial area over time. Biotic differentiation, in turn, is defined as increasing dissimilarity over time. Overall, changes in the spatial dissimilarities among assemblages (termed 'beta diversity') is an increasingly recognised feature of broader biodiversity change in the Anthropocene. Empirical evidence of biotic homogenisation and biotic differentiation remains scattered across different ecosystems. Most meta-analyses quantify the prevalence and direction of change in beta diversity, rather than attempting to identify underlying ecological drivers of such changes. By conceptualising the mechanisms that contribute to decreasing or increasing dissimilarity in the composition of ecological assemblages across space, environmental managers and conservation practitioners can make informed decisions about what interventions may be required to sustain biodiversity and can predict potential biodiversity outcomes of future disturbances. We systematically reviewed and synthesised published empirical evidence for ecological drivers of biotic homogenisation and differentiation across terrestrial, marine, and freshwater realms to derive conceptual models that explain changes in spatial beta diversity. We pursued five key themes in our review: (i) temporal environmental change; (ii) disturbance regime; (iii) connectivity alteration and species redistribution; (iv) habitat change; and (v) biotic and trophic interactions. Our first conceptual model highlights how biotic homogenisation and differentiation can occur as a function of changes in local (alpha) diversity or regional (gamma) diversity, independently of species invasions and losses due to changes in species occurrence among assemblages. Second, the direction and magnitude of change in beta diversity depends on the interaction between spatial variation (patchiness) and temporal variation (synchronicity) of disturbance events. Third, in the context of connectivity and species redistribution, divergent beta diversity outcomes occur as different species have different dispersal characteristics, and the magnitude of beta diversity change associated with species invasions also depends strongly on alpha and gamma diversity prior to species invasion. Fourth, beta diversity is positively linked with spatial environmental variability, such that biotic homogenisation and differentiation occur when environmental heterogeneity decreases or increases, respectively. Fifth, species interactions can influence beta diversity via habitat modification, disease, consumption (trophic dynamics), competition, and by altering ecosystem productivity. Our synthesis highlights the multitude of mechanisms that cause assemblages to be more or less spatially similar in composition (taxonomically, functionally, phylogenetically) through time. We consider that future studies should aim to enhance our collective understanding of ecological systems by clarifying the underlying mechanisms driving homogenisation or differentiation, rather than focusing only on reporting the prevalence and direction of change in beta diversity, per se.
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Affiliation(s)
- Robert J Rolls
- School of Environmental and Rural Sciences, University of New England, Armidale, New South Wales, 2351, Australia
| | - David C Deane
- School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Victoria, 3086, Australia
| | - Sarah E Johnson
- Natural Resources Department, Northland College, Ashland, WI, 54891, USA
| | - Jani Heino
- Geography Research Unit, University of Oulu, P.O. Box 8000, Oulu, FI-90014, Finland
| | - Marti J Anderson
- New Zealand Institute for Advanced Study (NZIAS), Massey University, Albany Campus, Auckland, New Zealand
| | - Kari E Ellingsen
- Norwegian Institute for Nature Research (NINA), Fram Centre, P.O. Box 6606 Langnes, Tromsø, 9296, Norway
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Guzy JC, Falk BG, Smith BJ, Willson JD, Reed RN, Aumen NG, Avery ML, Bartoszek IA, Campbell E, Cherkiss MS, Claunch NM, Currylow AF, Dean T, Dixon J, Engeman R, Funck S, Gibble R, Hengstebeck KC, Humphrey JS, Hunter ME, Josimovich JM, Ketterlin J, Kirkland M, Mazzotti FJ, McCleery R, Miller MA, McCollister M, Parker MR, Pittman SE, Rochford M, Romagosa C, Roybal A, Snow RW, Spencer MM, Waddle JH, Yackel Adams AA, Hart KM. Burmese pythons in Florida: A synthesis of biology, impacts, and management tools. NEOBIOTA 2023. [DOI: 10.3897/neobiota.80.90439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Burmese pythons (Python molurus bivittatus) are native to southeastern Asia, however, there is an established invasive population inhabiting much of southern Florida throughout the Greater Everglades Ecosystem. Pythons have severely impacted native species and ecosystems in Florida and represent one of the most intractable invasive-species management issues across the globe. The difficulty stems from a unique combination of inaccessible habitat and the cryptic and resilient nature of pythons that thrive in the subtropical environment of southern Florida, rendering them extremely challenging to detect. Here we provide a comprehensive review and synthesis of the science relevant to managing invasive Burmese pythons. We describe existing control tools and review challenges to productive research, identifying key knowledge gaps that would improve future research and decision making for python control.
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Currylow AF, Falk BG, Yackel Adams AA, Romagosa CM, Josimovich JM, Rochford MR, Cherkiss MS, Nafus MG, Hart KM, Mazzotti FJ, Snow RW, Reed RN. Size distribution and reproductive phenology of the invasive Burmese python (Python molurus bivittatus) in the Greater Everglades Ecosystem, Florida, USA. NEOBIOTA 2022. [DOI: 10.3897/neobiota.78.93788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The design of successful invasive species control programs is often hindered by the absence of basic demographic data on the targeted population. Establishment of invasive Burmese pythons (Python molurus bivittatus) in the Greater Everglades Ecosystem, Florida USA has led to local precipitous declines (> 90%) of mesomammal populations and is also a major threat to native populations of reptiles and birds. Efforts to control this species are ongoing but are hampered by the lack of access to and information on the expected biological patterns of pythons in southern Florida. We present data from more than 4,000 wild Burmese pythons that were removed in southern Florida over 26 years (1995–2021), the most robust dataset representing this invasive population to date. We used these data to characterize Burmese python size distribution, size at maturity, clutch size, and seasonal demographic and reproductive trends. We broadened the previously described size ranges by sex and, based on our newly defined size-stage classes, showed that males are smaller than females at sexual maturity, confirmed a positive correlation between maternal body size and potential clutch size, and developed predictive equations to facilitate demographic predictions. We also refined the annual breeding season (approx.100 days December into March), oviposition timing (May), and hatchling emergence and dispersal period (July through October) using correlations of capture morphometrics with observations of seasonal gonadal recrudescence (resurgence) and regression. Determination of reproductive output and timing can inform population models and help managers arrest population growth by targeting key aspects of python life history. These results define characteristics of the species in Florida and provide an enhanced understanding of the ecology and reproductive biology of Burmese pythons in their invasive Everglades range.
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Glebskiy Y, Acosta-Gutiérrez R, Cano-Santana Z. Effect of urbanization on the opossum Didelphis virginiana health and implications for zoonotic diseases. JOURNAL OF URBAN ECOLOGY 2022. [DOI: 10.1093/jue/juac015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Urban animals can be an important threat to human health as possible hosts of zoonotic diseases and their susceptibility to these diseases can depend on their overall health conditions. Thus, it is important to understand the factors that determine their health conditions. For this, we studied Virginia opossums (Didelphis virginiana) in six locations with different urbanization levels and types in Mexico City, Mexico. We trapped opossums and measured eight health-related characteristics (number of ectoparasites and tartar severity, among others) and estimated the percentage of area covered by the four main types of terrain (natural vegetation, managed vegetation, impermeable terrain and constructions). Data were analyzed by a canonical correspondence analysis. We found that impermeable terrain was related to negative health characteristics, while the constructions were opposite to impermeable terrain and mostly related to good health characteristics. At the same, time constructed areas held a smaller population than the natural areas. This suggests that constructed areas provide few shelters, but opossums are healthier there, while impermeable areas provide more shelter but cause more health problems to the animals, thus increasing the chances of zoonotic diseases. We recommend reducing the impermeable areas in city planning to contribute to a better health of the urban animals and therefore reduce risks of zoonotic diseases with potentially disastrous results.
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Affiliation(s)
- Yury Glebskiy
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, UNAM , Ciudad de Mexico, Mexico , 04510
- Posgrado en Ciencias Biológicas, UNAM , Ciudad de Mexico, Mexico , 04510
| | - Roxana Acosta-Gutiérrez
- Museo de Zoología “Alfonso L. Herrera”, Facultad de Ciencias, UNAM , Ciudad de Mexico, Mexico , 04510
| | - Zenón Cano-Santana
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, UNAM , Ciudad de Mexico, Mexico , 04510
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Piquet JC, López-Darias M. Invasive snake causes massive reduction of all endemic herpetofauna on Gran Canaria. Proc Biol Sci 2021; 288:20211939. [PMID: 34875190 PMCID: PMC8651408 DOI: 10.1098/rspb.2021.1939] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/11/2021] [Indexed: 11/12/2022] Open
Abstract
Invasive snakes represent a serious threat to island biodiversity, being responsible for far-reaching impacts that are noticeably understudied, particularly regarding native reptiles. We analysed the impact of the invasive California kingsnake, Lampropeltis californiae-recently introduced in the Canary Islands-on the abundance of all endemic herpetofauna of the island of Gran Canaria. We quantified the density in invaded and uninvaded sites for the Gran Canaria giant lizard, Gallotia stehlini, the Gran Canaria skink, Chalcides sexlineatus, and Boettger's wall gecko, Tarentola boettgeri. We used spatially explicit capture-recapture and distance-sampling methods for G. stehlini and active searches under rocks for the abundance of the other two reptiles. The abundance of all species was lower in invaded sites, with a reduction in the number of individuals greater than 90% for G. stehlini, greater than 80% for C. sexlineatus and greater than 50% for T. boettgeri in invaded sites. Our results illustrate the severe impact of L. californiae on the endemic herpetofauna of Gran Canaria and highlight the need for strengthened measures to manage this invasion. We also provide further evidence of the negative consequences of invasive snakes on island reptiles and emphasize the need for further research on this matter on islands worldwide.
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Affiliation(s)
- Julien C. Piquet
- Island Ecology and Evolution Research Group, Instituto de Productos Naturales y Agrobiología (IPNA-CSIC), 38206 La Laguna, Tenerife, Canary Islands, Spain
| | - Marta López-Darias
- Island Ecology and Evolution Research Group, Instituto de Productos Naturales y Agrobiología (IPNA-CSIC), 38206 La Laguna, Tenerife, Canary Islands, Spain
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Borden JB, Bohlman S, Scheffers BR. Niche lability mitigates the impact of invasion but not urbanization. Oecologia 2021; 198:1-10. [PMID: 34617142 DOI: 10.1007/s00442-021-05039-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 09/11/2021] [Indexed: 11/25/2022]
Abstract
Native species can coexist with invasive congeners by partitioning niche space; however, impacts from invasive species often occur alongside other disturbances. Native species' responses to the interactions of multiple disturbances remain poorly understood. Here we study the impacts of urbanization and an invasive congener on a native species. Using abundance (catch-per-unit effort) and vertical distribution of native green anoles (Anolis carolinensis) and invasive brown anoles (Anolis sagrei) across a gradient of natural-to-urban forests, we ask if niche shifting (lability) is occurring, and if it can mitigate impacts from one or both disturbances. We use generalized linear models to relate species abundances across the landscape to urbanization, forest structural complexity, and congener abundances (i.e., A. sagrei); and test for an interaction between urbanization and congener abundance. Our data show that A. sagrei presence results in a 17-fold upward shift in vertical niche of A. carolinensis-an 8.3 m shift in median perch height, and models reveal urbanization also drives an increase in A. carolinensis perch height. A. carolinensis and A. sagrei abundances negatively and positively correlate with urbanization, respectively, and neither species' abundance correlate with congener abundance. Despite a positive correlation between A. sagrei abundance and urbanization, our results do not show evidence of this interaction affecting A. carolinensis. Instead, niche lability appears to enable the native species to mitigate the impact of one driver of decline (invasive competition) while our data suggest it declines with the second (urbanization).
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Affiliation(s)
- Jesse B Borden
- School of Natural Resources and the Environment, University of Florida, Gainesville, FL, 32611-0430, USA.
| | - Stephanie Bohlman
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL, 32611-0430, USA
| | - Brett R Scheffers
- School of Natural Resources and the Environment, University of Florida, Gainesville, FL, 32611-0430, USA
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, 32611-0430, USA
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Invasive Burmese pythons alter host use and virus infection in the vector of a zoonotic virus. Commun Biol 2021; 4:804. [PMID: 34183751 PMCID: PMC8239020 DOI: 10.1038/s42003-021-02347-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 06/09/2021] [Indexed: 02/06/2023] Open
Abstract
The composition of wildlife communities can have strong effects on transmission of zoonotic vector-borne pathogens, with more diverse communities often supporting lower infection prevalence in vectors (dilution effect). The introduced Burmese python, Python bivittatus, is eliminating large and medium-sized mammals throughout southern Florida, USA, impacting local communities and the ecology of zoonotic pathogens. We investigated invasive predator-mediated impacts on ecology of Everglades virus (EVEV), a zoonotic pathogen endemic to Florida that circulates in mosquito-rodent cycle. Using binomial generalized linear mixed effects models of field data at areas of high and low python densities, we show that increasing diversity of dilution host (non-rodent mammals) is associated with decreasing blood meals on amplifying hosts (cotton rats), and that increasing cotton rat host use is associated with increasing EVEV infection in vector mosquitoes. The Burmese python has caused a dramatic decrease in mammal diversity in southern Florida, which has shifted vector host use towards EVEV amplifying hosts (rodents), resulting in an indirect increase in EVEV infection prevalence in vector mosquitoes, putatively elevating human transmission risk. Our results indicate that an invasive predator can impact wildlife communities in ways that indirectly affect human health, highlighting the need for conserving biological diversity and natural communities.
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Bartoszek IA, Smith BJ, Reed RN, Hart KM. Spatial ecology of invasive Burmese pythons in southwestern Florida. Ecosphere 2021. [DOI: 10.1002/ecs2.3564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
| | - Brian J. Smith
- Department of Wildland Resources and Conservation Center Utah State University 5230 Old Main Hill Logan Utah84322USA
| | - Robert N. Reed
- Pacific Island Ecosystems Research Center U.S. Geological Survey Hawaii Volcanoes National Park Hawaii96718USA
| | - Kristen M. Hart
- Wetland and Aquatic Research Center U.S. Geological Survey 3321 College Avenue Davie Florida33314USA
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9
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Louppe V, Herrel A, Pisanu B, Grouard S, Veron G. Assessing occupancy and activity of two invasive carnivores in two Caribbean islands: implications for insular ecosystems. J Zool (1987) 2020. [DOI: 10.1111/jzo.12845] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- V. Louppe
- Institut de Systématique, Evolution, Biodiversité (ISYEB) Muséum National d'Histoire Naturelle, CNRS Sorbonne Université EPHE Université des Antilles Paris France
| | - A. Herrel
- Mécanismes Adaptatifs et Evolution (MECADEV) Muséum National d'Histoire Naturelle, CNRS Paris France
| | - B. Pisanu
- UMS Patrimoine Naturel Office Français pour la Biodiversité Muséum National d'Histoire Naturelle, CNRS Paris France
| | - S. Grouard
- Archéozoologie, Archéobotanique Sociétés, Pratiques, Environnement (AASPE) Muséum National d'Histoire Naturelle – CNRS Paris France
| | - G. Veron
- Institut de Systématique, Evolution, Biodiversité (ISYEB) Muséum National d'Histoire Naturelle, CNRS Sorbonne Université EPHE Université des Antilles Paris France
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Taillie PJ, Jolly SR, Bobay LR, Sneckenberger S, McCleery RA. Habitat use across multiple scales suggests resilience to rising seas for endangered island endemic compared to sympatric invasive species. Anim Conserv 2020. [DOI: 10.1111/acv.12637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- P. J. Taillie
- Department of Wildlife Ecology and Conservation University of Florida Gainesville FL USA
| | - S. R. Jolly
- Department of Wildlife Ecology and Conservation University of Florida Gainesville FL USA
| | - L. R. Bobay
- Department of Wildlife Ecology and Conservation University of Florida Gainesville FL USA
| | - S. Sneckenberger
- South Florida Ecological Services Office United States Fish & Wildlife Service Vero Beach FL USA
| | - R. A. McCleery
- Department of Wildlife Ecology and Conservation University of Florida Gainesville FL USA
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Soto-Shoender JR, Gwinn DC, Sovie A, McCleery RA. Life-history traits moderate the susceptibility of native mammals to an invasive predator. Biol Invasions 2020. [DOI: 10.1007/s10530-020-02278-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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12
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Estimating Detection Probability for Burmese Pythons with Few Detections and Zero Recaptures. J HERPETOL 2020. [DOI: 10.1670/18-154] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Invasive Burmese pythons (Python bivittatus) are novel nest predators in wading bird colonies of the Florida Everglades. Biol Invasions 2019. [DOI: 10.1007/s10530-019-01979-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Orzechowski SCM, Frederick PC, Dorazio RM, Hunter ME. Environmental DNA sampling reveals high occupancy rates of invasive Burmese pythons at wading bird breeding aggregations in the central Everglades. PLoS One 2019; 14:e0213943. [PMID: 30970028 PMCID: PMC6457569 DOI: 10.1371/journal.pone.0213943] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/04/2019] [Indexed: 11/18/2022] Open
Abstract
The Burmese python (Python bivittatus) is now established as a breeding population throughout south Florida, USA. However, the extent of the invasion, and the ecological impacts of this novel apex predator on animal communities are incompletely known, in large part because Burmese pythons (hereafter “pythons”) are extremely cryptic and there has been no efficient way to detect them. Pythons are recently confirmed nest predators of long-legged wading bird breeding colonies (orders Ciconiiformes and Pelecaniformes). Pythons can consume large quantities of prey and may not be recognized as predators by wading birds, therefore they could be a particular threat to colonies. To quantify python occupancy rates at tree islands where wading birds breed, we utilized environmental DNA (eDNA) analysis—a genetic tool which detects shed DNA in water samples and provides high detection probabilities. We fitted multi-scale Bayesian occupancy models to test the prediction that pythons occupy islands with wading bird colonies at higher rates compared to representative control islands containing no breeding birds. Our results suggest that pythons are widely distributed across the central Everglades in proximity to active wading bird colonies. In support of our prediction that pythons are attracted to colonies, site-level python eDNA occupancy rates were higher at wading bird colonies (ψ = 0.88, 95% credible interval [0.59–1.00]) than at the control islands (ψ = 0.42 [0.16–0.80]) in April through June (n = 15 colony-control pairs). We found our water temperature proxy (time of day) to be informative of detection probability, in accordance with other studies demonstrating an effect of temperature on eDNA degradation in occupied samples. Individual sample concentrations ranged from 0.26 to 38.29 copies/μL and we generally detected higher concentrations of python eDNA in colony sites. Continued monitoring of wading bird colonies is warranted to determine the effect pythons are having on populations and investigate putative management activities.
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Affiliation(s)
- Sophia C. M. Orzechowski
- 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
| | - Robert M. Dorazio
- U.S. Geological Survey, Wetland and Aquatic Research Center, Gainesville, Florida, United States of America
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
| | - Margaret E. Hunter
- U.S. Geological Survey, Wetland and Aquatic Research Center, Gainesville, Florida, United States of America
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Hunter ME, Johnson NA, Smith BJ, Davis MC, Butterfield JSS, Snow RW, Hart KM. Cytonuclear discordance in the Florida Everglades invasive Burmese python ( Python bivittatus) population reveals possible hybridization with the Indian python ( P. molurus). Ecol Evol 2018; 8:9034-9047. [PMID: 30271564 PMCID: PMC6157680 DOI: 10.1002/ece3.4423] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 06/08/2018] [Accepted: 06/22/2018] [Indexed: 12/04/2022] Open
Abstract
The invasive Burmese python (Python bivittatus) has been reproducing in the Florida Everglades since the 1980s. These giant constrictor snakes have caused a precipitous decline in small mammal populations in southern Florida following escapes or releases from the commercial pet trade. To better understand the invasion pathway and genetic composition of the population, two mitochondrial (mtDNA) loci across 1,398 base pairs were sequenced on 426 snakes and 22 microsatellites were assessed on 389 snakes. Concatenated mtDNA sequences produced six haplotypes with an average nucleotide and haplotype diversity of π = 0.002 and h = 0.097, respectively. Samples collected in Florida from morphologically identified P. bivittatus snakes were similar to published cytochrome oxidase 1 and cytochrome b sequences from both P. bivittatus and Python molurus and were highly divergent (genetic distances of 5.4% and 4.3%, respectively). The average number of microsatellite alleles and expected heterozygosity were N A = 5.50 and H E = 0.60, respectively. Nuclear Bayesian assignment tests supported two genetically distinct groups and an admixed group, not geographically differentiated. The effective population size (N E = 315.1) was lower than expected for a population this large, but reflected the low genetic diversity overall. The patterns of genetic diversity between mtDNA and microsatellites were disparate, indicating nuclear introgression of separate mtDNA lineages corresponding to cytonuclear discordance. The introgression likely occurred prior to the invasion, but genetic information on the native range and commercial trade is needed for verification. Our finding that the Florida python population is comprised of distinct lineages suggests greater standing variation for adaptation and the potential for broader areas of suitable habitat in the invaded range.
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Affiliation(s)
- Margaret E. Hunter
- U.S. Geological SurveyWetland and Aquatic Research CenterGainesvilleFlorida
| | - Nathan A. Johnson
- U.S. Geological SurveyWetland and Aquatic Research CenterGainesvilleFlorida
| | - Brian J. Smith
- Wetland and Aquatic Research CenterCherokee Nation TechnologiesDavieFlorida
| | - Michelle C. Davis
- U.S. Geological SurveyWetland and Aquatic Research CenterGainesvilleFlorida
| | | | - Ray W. Snow
- U.S. National Park ServiceEverglades National ParkHomesteadFlorida
| | - Kristen M. Hart
- U.S. Geological SurveyWetland and Aquatic Research CenterDavieFlorida
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