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Lowe WH, Addis BR, Cochrane MM. Outbreeding reduces survival during metamorphosis in a headwater stream salamander. Mol Ecol 2024:e17375. [PMID: 38699973 DOI: 10.1111/mec.17375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 02/22/2024] [Accepted: 03/01/2024] [Indexed: 05/05/2024]
Abstract
Assessing direct fitness effects of individual genetic diversity is challenging due to the intensive and long-term data needed to quantify survival and reproduction in the wild. But resolving these effects is necessary to determine how inbreeding and outbreeding influence eco-evolutionary processes. We used 8 years of capture-recapture data and single nucleotide polymorphism genotypes for 1906 individuals to test for effects of individual heterozygosity on stage-specific survival probabilities in the salamander Gyrinophilus porphyriticus. The life cycle of G. porphyriticus includes an aquatic larval stage followed by metamorphosis into a semi-aquatic adult stage. In our study populations, the larval stage lasts 6-10 years, metamorphosis takes several months, and lifespan can reach 20 years. Previous studies showed that metamorphosis is a sensitive life stage, leading us to predict that fitness effects of individual heterozygosity would occur during metamorphosis. Consistent with this prediction, monthly probability of survival during metamorphosis declined with multi-locus heterozygosity (MLH), from 0.38 at the lowest MLH (0.10) to 0.06 at the highest MLH (0.38), a reduction of 84%. Body condition of larvae also declined significantly with increasing MLH. These relationships were consistent in the three study streams. With evidence of localised inbreeding within streams, these results suggest that outbreeding disrupts adaptations in pre-metamorphic and metamorphic individuals to environmental gradients along streams, adding to evidence that headwater streams are hotspots of microgeographic adaptation. Our results also underscore the importance of incorporating life history in analyses of the fitness effects of individual genetic diversity and suggest that metamorphosis and similar discrete life stage transitions may be critical periods of viability selection.
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Affiliation(s)
- Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Brett R Addis
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Madaline M Cochrane
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
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Cochrane MM, Addis BR, Lowe WH. Stage-Specific Demographic Effects of Hydrologic Variation in a Stream Salamander. Am Nat 2024; 203:E175-E187. [PMID: 38635365 DOI: 10.1086/729466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
AbstractWe lack a strong understanding of how organisms with complex life histories respond to climate variation. Many stream-associated species have multistage life histories that are likely to influence the demographic consequences of floods and droughts. However, tracking stage-specific demographic responses requires high-resolution, long-term data that are rare. We used 8 years of capture-recapture data for the headwater stream salamander Gyrinophilus porphyriticus to quantify the effects of flooding and drying magnitude on stage-specific vital rates and population growth. Drying reduced larval recruitment but increased the probability of metamorphosis (i.e., adult recruitment). Flooding reduced adult recruitment but had no effect on larval recruitment. Larval and adult survival declined with flooding but were unaffected by drying. Annual population growth rates (λ) declined with flooding and drying. Lambda also declined over the study period (2012-2021), although mean λ was 1.0 over this period. Our results indicate that G. porphyriticus populations are resilient to hydrologic variation because of compensatory effects on recruitment of larvae versus adults (i.e., reproduction vs. metamorphosis). Complex life cycles may enable this resilience to climate variation by creating opportunities for compensatory demographic responses across stages. However, more frequent and intense hydrologic variation in the latter half of this study contributed to a decline in λ over time, suggesting that increasing environmental variability poses a threat even when demographic compensation occurs.
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Cochrane MM, Addis BR, Swartz LK, Lowe WH. Individual growth rates and size at metamorphosis increase with watershed area in a stream salamander. Ecology 2024; 105:e4217. [PMID: 38037284 DOI: 10.1002/ecy.4217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/20/2023] [Accepted: 10/26/2023] [Indexed: 12/02/2023]
Abstract
A fundamental goal of ecology is to understand how the physical environment influences intraspecific variability in life history and, consequently, fitness. In streams, discharge and associated habitat conditions change along a continuum from intermittency to permanence: Headwater streams typically have smaller watersheds and are thus more prone to drying than higher-order streams with larger watersheds and more consistent discharge. However, few empirical studies have assessed life history and associated population responses to this continuum in aquatic organisms. We tested the prediction that individual growth, rate of development, and population growth increase with watershed area in the long-lived stream salamander Gyrinophilus porphyriticus, where we use watershed area as a proxy for hydrologic intermittence. To address this hypothesis, we used 8 years of mark-recapture data from 53 reaches across 10 headwater streams in New Hampshire, USA. Individual growth rates and mean size at metamorphosis increased with watershed area for watersheds from 0.12 to 1.66 km2 . Population growth rates increased with watershed area; however, this result was not statistically significant at our sample size. Mean age of metamorphosis did not vary across watershed areas. Lower individual growth rates and smaller sizes at metamorphosis likely contributed to reduced lifetime fecundity and population growth in reaches with the smallest watershed areas and highest vulnerability to drought. These responses suggest that as droughts increase due to climate change, headwater specialists in hydrologically intermittent environments will experience a reduction in fitness due to smaller body sizes or other growth-related mechanisms.
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Affiliation(s)
- Madaline M Cochrane
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Brett R Addis
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Leah K Swartz
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
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Lowe WH, Addis BR, Cochrane MM, Swartz LK. Source-sink dynamics within a complex life history. Ecology 2023; 104:e3991. [PMID: 36772972 DOI: 10.1002/ecy.3991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 11/23/2022] [Accepted: 12/01/2022] [Indexed: 02/12/2023]
Abstract
Source-sink patch dynamics occur when movement from sources stabilizes sinks by compensating for low local vital rates. The mechanisms underlying source-sink dynamics may be complicated in species that undergo transitions between discrete life stages, particularly when stages have overlapping habitat requirements and similar movement abilities. In these species, for example, the demographic effects of movement by one stage may augment or offset the effects of movement by another stage. We used a stream salamander system to investigate patch dynamics within this form of complex life history. Specifically, we tested the hypothesis that the salamander Gyrinophilus porphyriticus experiences source-sink dynamics in riffles and pools, the dominant geomorphic patch types in headwater streams. We estimated stage-specific survival probabilities in riffles and pools and stage-specific movement probabilities between the two patch types using 8 years of capture-recapture data on 4491 individuals, including premetamorphic larvae and postmetamorphic adults. We then incorporated survival and movement probabilities into a stage-structured, two-patch model to determine the demographic interactions between riffles and pools. Monthly survival probabilities of both stages were higher in pools than in riffles. Larvae were more likely to move from riffles to pools, but adults were more likely to move from pools to riffles, despite experiencing much lower survival in riffles. In simulations, eliminating interpatch movements by both stages indicated that riffles are sinks that rely on immigration from pools for stability. Allowing only larvae to move stabilized both patch types, but allowing only adults to move destabilized pools due to the demographic cost of adult emigration. These results indicated that larval movement not only stabilizes riffles, but also offsets the destabilizing effects of maladaptive adult movement. Similar patch dynamics may emerge in any structured population in which movement and local vital rates differ by age, size, or stage. Addressing these forms of internal demographic structure in patch dynamics analyses will help to refine and advance general understanding of spatial ecology.
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Affiliation(s)
- Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Brett R Addis
- D.B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - Madaline M Cochrane
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Leah K Swartz
- Montana Freshwater Partners, Livingston, Montana, USA
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Addis BR, Lowe WH. Environmentally associated variation in dispersal distance affects inbreeding risk in a stream salamander. Am Nat 2022; 200:802-814. [DOI: 10.1086/721763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Bryant AR, Gabor CR, Swartz LK, Wagner R, Cochrane MM, Lowe WH. Differences in Corticosterone Release Rates of Larval Spring Salamanders (Gyrinophilus porphyriticus) in Response to Native Fish Presence. Biology 2022; 11:biology11040484. [PMID: 35453684 PMCID: PMC9030379 DOI: 10.3390/biology11040484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/11/2022] [Accepted: 03/17/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary In amphibians, glucocorticoid hormones play a key role in the response to predation stress. Predators can directly affect prey via injury and death, but they can also have indirect effects due to the activity of glucocorticoids. The regulation of glucocorticoids can differ between populations that have co-evolved with predators and those that have not. We measured glucocorticoids at baseline and in response to a novel stressor in free-living larval salamanders that either live with or without fish predators naturally. We found that salamanders living with fish predators had lower measures of glucocorticoids than those without fish predators. Our study indicates that predator presence alters glucocorticoid regulation, which may allow species to better cope with native and introduced predators. Abstract Invasive fish predators are an important factor causing amphibian declines and may have direct and indirect effects on amphibian survival. For example, early non-lethal exposure to these stressors may reduce survival in later life stages, especially in biphasic species. In amphibians, the glucocorticoid hormone corticosterone is released by the hypothalamo–pituitary–interrenal axis (HPI), as an adaptive physiological response to environmental stressors. The corticosterone response (baseline and response to acute stressors) is highly flexible and context dependent, and this variation can allow individuals to alter their phenotype and behavior with environmental changes, ultimately increasing survival. We sampled larvae of the spring salamander (Gyrinophilus porphyriticus) from two streams that each contained predatory brook trout (Slavelinus fontinalis) in the lower reaches and no predatory brook trout in the upper reaches. We measured baseline and stress-induced corticosterone release rates of larvae from the lower and upper reaches using a non-invasive water-borne hormone assay. We hypothesized that corticosterone release rates would differ between larvae from fish-present reaches and larvae from fish-free reaches. We found that baseline and stressor-induced corticosterone release rates were downregulated in larvae from reaches with fish predators. These results indicate that individuals from reaches with predatory trout are responding to fish predators by downregulating corticosterone while maintaining an active HPI axis. This may allow larvae more time to grow before metamorphosing, while also allowing them to physiologically respond to novel stressors. However, prolonged downregulation of corticosterone release rates can impact growth in post-metamorphic individuals.
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Affiliation(s)
- Amanda R. Bryant
- Department of Biology, Texas State University, San Marcos, TX 78666, USA;
| | - Caitlin R. Gabor
- Department of Biology, Texas State University, San Marcos, TX 78666, USA;
- Correspondence: author:
| | | | - Ryan Wagner
- School of Environment and Natural Resources, The Ohio State University Columbus, Columbus, OH 43210, USA;
| | - Madaline M. Cochrane
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (M.M.C.); (W.H.L.)
| | - Winsor H. Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (M.M.C.); (W.H.L.)
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Cayuela H, Lemaître JF, Léna JP, Ronget V, Martínez-Solano I, Muths E, Pilliod DS, Schmidt BR, Sánchez-Montes G, Gutiérrez-Rodríguez J, Pyke G, Grossenbacher K, Lenzi O, Bosch J, Beard KH, Woolbright LL, Lambert BA, Green DM, Jreidini N, Garwood JM, Fisher RN, Matthews K, Dudgeon D, Lau A, Speybroeck J, Homan R, Jehle R, Başkale E, Mori E, Arntzen JW, Joly P, Stiles RM, Lannoo MJ, Maerz JC, Lowe WH, Valenzuela-Sánchez A, Christiansen DG, Angelini C, Thirion JM, Merilä J, Colli GR, Vasconcellos MM, Boas TCV, Arantes ÍDC, Levionnois P, Reinke BA, Vieira C, Marais GAB, Gaillard JM, Miller DAW. Sex-related differences in aging rate are associated with sex chromosome system in amphibians. Evolution 2021; 76:346-356. [PMID: 34878663 PMCID: PMC9304222 DOI: 10.1111/evo.14410] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 12/03/2022]
Abstract
Sex‐related differences in mortality are widespread in the animal kingdom. Although studies have shown that sex determination systems might drive lifespan evolution, sex chromosome influence on aging rates have not been investigated so far, likely due to an apparent lack of demographic data from clades including both XY (with heterogametic males) and ZW (heterogametic females) systems. Taking advantage of a unique collection of capture–recapture datasets in amphibians, a vertebrate group where XY and ZW systems have repeatedly evolved over the past 200 million years, we examined whether sex heterogamy can predict sex differences in aging rates and lifespans. We showed that the strength and direction of sex differences in aging rates (and not lifespan) differ between XY and ZW systems. Sex‐specific variation in aging rates was moderate within each system, but aging rates tended to be consistently higher in the heterogametic sex. This led to small but detectable effects of sex chromosome system on sex differences in aging rates in our models. Although preliminary, our results suggest that exposed recessive deleterious mutations on the X/Z chromosome (the “unguarded X/Z effect”) or repeat‐rich Y/W chromosome (the “toxic Y/W effect”) could accelerate aging in the heterogametic sex in some vertebrate clades.
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Affiliation(s)
- Hugo Cayuela
- Department of Ecology and Evolution, University of Lausanne, Lausanne, 1015, Switzerland
| | - Jean-François Lemaître
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, F-769622, France
| | - Jean-Paul Léna
- Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR5023 LEHNA, Villeurbanne, F-69622, France
| | - Victor Ronget
- Unité Eco-anthropologie (EA), Muséum National d'Histoire Naturelle, CNRS, Université Paris Diderot, Paris, F-75016, France
| | - Iñigo Martínez-Solano
- Museo Nacional de Ciencias Naturales, CSIC, c/ José Gutiérrez Abascal, 2, Madrid, 28006, Spain
| | - Erin Muths
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, 80526, USA
| | - David S Pilliod
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 970 Lusk Street, Boise, ID, 83706, USA
| | - Benedikt R Schmidt
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zürich, 8057, Switzerland.,Info fauna karch, Neuchâtel, 2000, Switzerland
| | - Gregorio Sánchez-Montes
- Museo Nacional de Ciencias Naturales, CSIC, c/ José Gutiérrez Abascal, 2, Madrid, 28006, Spain
| | - Jorge Gutiérrez-Rodríguez
- Museo Nacional de Ciencias Naturales, CSIC, c/ José Gutiérrez Abascal, 2, Madrid, 28006, Spain.,Department of Integrative Ecology, Estación Biológica de Doñana (EBD-CSIC), Seville, Spain
| | - Graham Pyke
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, PR China.,Department of Biological Sciences, Macquarie University, Ryde, NSW, 2109, Australia
| | - Kurt Grossenbacher
- Abteilung Wirbeltiere, Naturhistorisches Museum, Bernastrasse 15, Bern, 3005, Switzerland
| | - Omar Lenzi
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zürich, 8057, Switzerland
| | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC, c/ José Gutiérrez Abascal, 2, Madrid, 28006, Spain.,UMIB-Research Unit of Biodiversity (CSIC, UO, PA), Universidad de Oviedo, Campus de Mieres, Mieres, 33600, Spain.,Centro de Investigación, Seguimiento y Evaluación, Sierra de Guadarrama National Park, Cta. M-604, Km 27.6, Rascafría, 28740, Spain
| | - Karen H Beard
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, Utah, 84322, USA
| | - Lawrence L Woolbright
- Biology Department, Siena College, 515 Loudon Road, Loudonville, New York, 12211, USA
| | - Brad A Lambert
- Colorado Natural Heritage Program, Colorado State University, Fort Collins, Colorado, 80523-1475, USA
| | - David M Green
- Redpath Museum, McGill University, Montreal, QC, H3A 0C4, Canada
| | | | - Justin M Garwood
- California Department of Fish and Wildlife, 5341 Ericson Way, Arcata, CA, 95521, USA
| | - Robert N Fisher
- Western Ecological Research Center, U.S. Geological Survey, San Diego, CA, 92101, USA
| | - Kathleen Matthews
- USDA Forest Service, Pacific Southwest Research Station, Albany, California, USA
| | - David Dudgeon
- Division of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR
| | - Anthony Lau
- Science Unit, Lingnan University, Hong Kong, China
| | - Jeroen Speybroeck
- Research Institute for Nature and Forest, Havenlaan 88 bus 73, Brussel, 1000, Belgium
| | - Rebecca Homan
- Biology Department, Denison University, Granville, Ohio, USA
| | - Robert Jehle
- School of Science, Engineering and Environment, University of Salford, Salford, UK
| | - Eyup Başkale
- Department of Biology, Faculty of Science and Arts, Pamukkale University, Denizli, Turkey
| | - Emiliano Mori
- Consiglio Nazionale delle Ricerche, Istituto di Ricerca sugli Ecosistemi Terrestri, Via Madonna del Piano 10, Sesto Fiorentino, 50019, Italy
| | - Jan W Arntzen
- Naturalis Biodiversity Center, Leiden, The Netherlands
| | - Pierre Joly
- Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR5023 LEHNA, Villeurbanne, F-69622, France
| | - Rochelle M Stiles
- San Francisco Zoological Society, 1 Zoo Road, San Francisco, California, 94132, USA
| | - Michael J Lannoo
- Indiana University School of Medicine-TH, 620 Chestnut Street, Terre Haute, Indiana, 47809, USA
| | - John C Maerz
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812, USA
| | - Andrés Valenzuela-Sánchez
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, 5090000, Chile.,ONG Ranita de Darwin, Valdivia, 5112144, Chile
| | - Ditte G Christiansen
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zürich, 8057, Switzerland
| | - Claudio Angelini
- Salamandrina Sezzese Search Society, via G. Marconi 30, Sezze, 04018, Italy
| | - Jean-Marc Thirion
- Objectifs Biodiversité, 22 rue du Dr. Gilbert, Pont-l'Abbé-d'Arnoult, 17250, France
| | - Juha Merilä
- Division of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR.,Ecological Genetics Research Unit, Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, 00014, Finland
| | - Guarino R Colli
- Departamento de Zoologia, Universidade de Brasília, Brasília, Distrito Federal, 70910-900, Brazil
| | - Mariana M Vasconcellos
- Department of Biology, City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Taissa C V Boas
- Departamento de Zoologia, Universidade de Brasília, Brasília, Distrito Federal, 70910-900, Brazil
| | - Ísis da C Arantes
- Department of Biology, University of Mississippi, Oxford, MS, 38677, USA
| | - Pauline Levionnois
- Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR5023 LEHNA, Villeurbanne, F-69622, France
| | - Beth A Reinke
- Department of Biology, Northeastern Illinois University, 5500 North St. Louis Avenue, Chicago, IL, 60625, USA
| | - Cristina Vieira
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, F-769622, France
| | - Gabriel A B Marais
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, F-769622, France.,LEAF- Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Portugal
| | - Jean-Michel Gaillard
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, F-769622, France
| | - David A W Miller
- Department of Ecosystem Sciences and Management, The Pennsylvania State University, University Park, Pennsylvania, USA
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Lowe WH, Martin TE, Skelly DK, Woods HA. Thanks to Song et al. Trends Ecol Evol 2021; 36:978. [PMID: 34481688 DOI: 10.1016/j.tree.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 10/20/2022]
Affiliation(s)
- Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA.
| | - Thomas E Martin
- US Geological Survey, Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT 59812, USA
| | - David K Skelly
- School of the Environment, Yale University, New Haven, CT 06520, USA
| | - H Arthur Woods
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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Bayer MO, Lowe WH. Top-Down Effects of Salamanders on Macroinvertebrates in Fishless Headwater Streams. HERPETOLOGICA 2021. [DOI: 10.1655/herpetologica-d-20-00054.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Miriam O. Bayer
- Wildlife Biology Program, University of Montana, College of Forestry and Conservation, Missoula, MT 59812, USA
| | - Winsor H. Lowe
- Wildlife Biology Program, University of Montana, College of Forestry and Conservation, Missoula, MT 59812, USA
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Strait JT, Eby LA, Kovach RP, Muhlfeld CC, Boyer MC, Amish SJ, Smith S, Lowe WH, Luikart G. Hybridization alters growth and migratory life-history expression of native trout. Evol Appl 2021; 14:821-833. [PMID: 33767755 PMCID: PMC7980306 DOI: 10.1111/eva.13163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/25/2020] [Accepted: 10/12/2020] [Indexed: 11/29/2022] Open
Abstract
Human-mediated hybridization threatens many native species, but the effects of introgressive hybridization on life-history expression are rarely quantified, especially in vertebrates. We quantified the effects of non-native rainbow trout admixture on important life-history traits including growth and partial migration behavior in three populations of westslope cutthroat trout over five years. Rainbow trout admixture was associated with increased summer growth rates in all populations and decreased spring growth rates in two populations with cooler spring temperatures. These results indicate that non-native admixture may increase growth under warmer conditions, but cutthroat trout have higher growth rates during cooler periods. Non-native admixture consistently increased expression of migratory behavior, suggesting that there is a genomic basis for life-history differences between these species. Our results show that effects of interspecific hybridization on fitness traits can be the product of genotype-by-environment interactions even when there are minor differences in environmental optima between hybridizing species. These results also indicate that while environmentally mediated traits like growth may play a role in population-level consequences of admixture, strong genetic influences on migratory life-history differences between these species likely explains the continued spread of non-native hybridization at the landscape-level, despite selection against hybrids at the population-level.
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Affiliation(s)
- Jeffrey T. Strait
- Wildlife Biology Program, W.A. Franke College of Forestry and ConservationUniversity of MontanaMissoulaMTUSA
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
| | - Lisa A. Eby
- Wildlife Biology Program, W.A. Franke College of Forestry and ConservationUniversity of MontanaMissoulaMTUSA
| | - Ryan P. Kovach
- Montana Fish, Wildlife, and ParksUniversity of Montana Fish Conservation Genetics LabMissoulaMTUSA
| | - Clint C. Muhlfeld
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
- U.S. Geological SurveyNorthern Rocky Mountain Science CenterGlacier National ParkWest GlacierMTUSA
| | | | - Stephen J. Amish
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
| | - Seth Smith
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
| | - Winsor H. Lowe
- Division of Biological SciencesUniversity of MontanaMissoulaMTUSA
| | - Gordon Luikart
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
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Bayer MO, Swartz LK, Lowe WH. Predictors of Biofilm Biomass in Oligotrophic Headwater Streams. Northeast Nat (Steuben) 2021. [DOI: 10.1656/045.028.0103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Miriam O. Bayer
- Wildlife Biology Program, University of Montana, Missoula, MT 59812
| | - Leah K. Swartz
- Division of Biological Sciences, University of Montana, Missoula, MT 59812
| | - Winsor H. Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT 59812
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12
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Lowe WH, Martin TE, Skelly DK, Woods HA. Metamorphosis in an Era of Increasing Climate Variability. Trends Ecol Evol 2021; 36:360-375. [PMID: 33414021 DOI: 10.1016/j.tree.2020.11.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022]
Abstract
Most animals have complex life cycles including metamorphosis or other discrete life stage transitions, during which individuals may be particularly vulnerable to environmental stressors. With climate change, individuals will be exposed to increasing thermal and hydrologic variability during metamorphosis, which may affect survival and performance through physiological, behavioral, and ecological mechanisms. Furthermore, because metamorphosis entails changes in traits and vital rates, it is likely to play an important role in how populations respond to increasing climate variability. To identify mechanisms underlying population responses and associated trait and life history evolution, we need new approaches to estimating changes in individual traits and performance throughout metamorphosis, and we need to integrate metamorphosis as an explicit life stage in analytical models.
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Affiliation(s)
- Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA.
| | - Thomas E Martin
- US Geological Survey, Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT 59812, USA
| | - David K Skelly
- School of the Environment, Yale University, New Haven, CT 06520, USA
| | - H Arthur Woods
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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13
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Addis BR, Lowe WH. Long-term survival probability, not current habitat quality, predicts dispersal distance in a stream salamander. Ecology 2020; 101:e02982. [PMID: 31958140 DOI: 10.1002/ecy.2982] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/24/2019] [Accepted: 12/04/2019] [Indexed: 11/10/2022]
Abstract
Dispersal evolves as an adaptive mechanism to optimize individual fitness across the landscape. Specifically, dispersal represents a mechanism to escape fitness costs resulting from changes in environmental conditions. Decades of empirical work suggest that individuals use local habitat cues to make movement decisions, but theory predicts that dispersal can also evolve as a fixed trait, independent of local conditions, in environments characterized by a history of stochastic spatiotemporal variation. Until now, however, both conditional and fixed models of dispersal evolution have primarily been evaluated using emigration data (stay vs. leave), and not dispersal distances: a more comprehensive measure of dispersal. Our goal was to test whether conditional or fixed models of dispersal evolution predict variation in dispersal distance in the stream salamander Gyrinophilus porphyriticus. We quantified variation in habitat conditions using measures of salamander performance from 4 yr of spatially explicit, capture-mark-recapture (CMR) data across three headwater streams in the Hubbard Brook Experimental Forest in central New Hampshire, USA. We used body condition as an index of local habitat quality that individuals may use to make dispersal decisions, and survival probability estimated from multistate CMR models as an index of mortality risk resulting from the long-term history of environmental variation. We found that dispersal distances increased with declining survival probability, indicating that salamanders disperse further in risky environments. Dispersal distances were unrelated to spatial variation in body condition, suggesting that salamanders do not base dispersal distance decisions on local habitat quality. Our study provides the first empirical support for fixed models of dispersal evolution, which predict that dispersal evolves in response to a history of spatiotemporal environmental variation, rather than as a conditional response to current habitat conditions. More broadly, this study underscores the value of assessing alternative scales of environmental variation to gain a more complete and balanced understanding of dispersal evolution.
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Affiliation(s)
- Brett R Addis
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812, USA
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812, USA
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14
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Abstract
Abstract
Purpose of Review
We synthesize recent methodological and conceptual advances in the field of riverscape ecology, emphasizing areas of synergy with current research in landscape ecology.
Recent Findings
Recent advances in riverscape ecology highlight the need for spatially explicit examinations of how network structure influences ecological pattern and process, instead of the simple linear (upstream-downstream) view. Developments in GIS, remote sensing, and computer technologies already offer powerful tools for the application of patch- and gradient-based models for characterizing abiotic and biotic heterogeneity across a range of spatial and temporal scales. Along with graph-based analyses and spatial statistical stream network models (i.e., geostatistical modelling), these approaches offer improved capabilities for quantifying spatial and temporal heterogeneity and connectivity relationships, thereby allowing for rigorous and high-resolution analyses of pattern, process, and scale relationships.
Summary
Spatially explicit network approaches are able to quantify and predict biogeochemical, hydromorphological, and ecological patterns and processes more precisely than models based on longitudinal or lateral riverine gradients alone. Currently, local habitat characteristics appear to be more important than spatial effects in determining population and community dynamics, but this conclusion may change with direct quantification of the movement of materials, energy, and organisms along channels and across ecosystem boundaries—a key to improving riverscape ecology. Coupling spatially explicit riverscape models with optimization approaches will improve land protection and water management efforts, and help to resolve the land sharing vs. land sparing debate.
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15
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Swartz LK, Lowe WH, Muths EL, Hossack BR. Species‐specific responses to wetland mitigation among amphibians in the Greater Yellowstone Ecosystem. Restor Ecol 2019. [DOI: 10.1111/rec.13031] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Leah K. Swartz
- Wildlife Biology ProgramUniversity of Montana Missoula MT U.S.A
- Division of Biological SciencesUniversity of Montana Missoula MT U.S.A
| | - Winsor H. Lowe
- Division of Biological SciencesUniversity of Montana Missoula MT U.S.A
| | - Erin L. Muths
- U.S. Geological SurveyFort Collins Science Center Fort Collins CO U.S.A
| | - Blake R. Hossack
- U.S. Geological SurveyNorthern Rocky Mountain Science Center Missoula MT U.S.A
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16
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Addis BR, Tobalske BW, Davenport JM, Lowe WH. A distance-performance trade-off in the phenotypic basis of dispersal. Ecol Evol 2019; 9:10644-10653. [PMID: 31624572 PMCID: PMC6787857 DOI: 10.1002/ece3.5583] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 07/12/2019] [Accepted: 07/28/2019] [Indexed: 11/09/2022] Open
Abstract
Across taxa, individuals vary in how far they disperse, with most individuals staying close to their origin and fewer dispersing long distances. Costs associated with dispersal (e.g., energy, risk) are widely believed to trade off with benefits (e.g., reduced competition, increased reproductive success) to influence dispersal propensity. However, this framework has not been applied to understand variation in dispersal distance, which is instead generally attributed to extrinsic environmental factors. We alternatively hypothesized that variation in dispersal distances results from trade-offs associated with other aspects of locomotor performance. We tested this hypothesis in the stream salamander Gyrinophilus porphyriticus and found that salamanders that dispersed farther in the field had longer forelimbs but swam at slower velocities under experimental conditions. The reduced swimming performance of long-distance dispersers likely results from drag imposed by longer forelimbs. Longer forelimbs may facilitate moving longer distances, but the proximate costs associated with reduced swimming performance may help to explain the rarity of long-distance dispersal. The historical focus on environmental drivers of dispersal distances misses the importance of individual traits and associated trade-offs among traits affecting locomotion.
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Affiliation(s)
- Brett R. Addis
- Division of Biological SciencesUniversity of MontanaMissoulaMTUSA
| | - Bret W. Tobalske
- Division of Biological SciencesUniversity of MontanaMissoulaMTUSA
| | | | - Winsor H. Lowe
- Division of Biological SciencesUniversity of MontanaMissoulaMTUSA
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17
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Honeycutt RK, Garwood JM, Lowe WH, Hossack BR. Spatial capture-recapture reveals age- and sex-specific survival and movement in stream amphibians. Oecologia 2019; 190:821-833. [PMID: 31309278 DOI: 10.1007/s00442-019-04464-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/04/2019] [Indexed: 11/26/2022]
Abstract
Life-history information sets the foundation for our understanding of ecology and conservation requirements. For many species, this information is lacking even for basic demographic rates such as survival and movement. When survival and movement estimates are available, they are often derived from mixed demographic groups and do not consider differences among life stages or sexes, which is critical, because life stages and sexes often contribute differentially to population dynamics. We used hierarchical models informed with spatial capture-mark-recapture data of Ascaphus montanus (Rocky Mountain tailed frog) in five streams and A. truei (coastal tailed frog) in one stream to estimate variation in survival and movement by sex and age, represented by size. By incorporating survival and movement into a single model, we were able to estimate both parameters with limited bias. Annual survival was similar between sexes of A. montanus [females = 0.885 (95% CI 0.614-1), males = 0.901 (0.657-1)], but was slightly higher for female A. truei [0.836 (0.560-0.993)] than for males [0.664 (0.354-0.962)]. Survival of A. montanus peaked at mid-age, suggesting that lower survival of young and actuarial senescence may influence population demographics. Our models suggest that younger A. montanus moved farther than older individuals, and that females moved farther than males in both species. Our results provide uncommon insight into age- and sex-specific rates of survival and movement that are crucial elements of life-history strategies and are important for modeling population growth and prescribing conservation actions.
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Affiliation(s)
- R Ken Honeycutt
- U.S. Geological Survey, Northern Rocky Mountain Science Center, 800 E. Beckwith Avenue, Missoula, MT, 59801, USA.
| | - Justin M Garwood
- California Department of Fish and Wildlife, 5341 Ericson Way, Arcata, CA, 95521, USA
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT, 59812, USA
| | - Blake R Hossack
- U.S. Geological Survey, Northern Rocky Mountain Science Center, 800 E. Beckwith Avenue, Missoula, MT, 59801, USA
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18
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Rodenhouse NL, Lowe WH, Gebauer RLE, McFarland KP, Bank MS. Mercury bioaccumulation in temperate forest food webs associated with headwater streams. Sci Total Environ 2019; 665:1125-1134. [PMID: 30893744 DOI: 10.1016/j.scitotenv.2019.02.151] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/25/2019] [Accepted: 02/09/2019] [Indexed: 06/09/2023]
Abstract
The soils and food webs associated with mid to high elevation, forested, headwater streams in northeastern North America are potential hotspots for mercury (Hg) methylation and bioaccumulation, but are not well studied. Our goals were to quantify total Hg (THg) and methyl Hg (MeHg) concentrations in soils and terrestrial food webs associated with headwater streams of northern hardwood forests to identify predictors of small-scale spatial variation in Hg bioaccumulation. We sampled soil characteristics that promote Hg methylation including pH, sulfur and calcium content, and organic matter. To assess spatial variation, we sampled at high (~700 m asl) and mid elevations (~500 m asl), both adjacent to (<1 m) and away from (>75 m) three replicate headwater streams in each of two watersheds of the White Mountains region, New Hampshire, USA. Soils of these forested watersheds differed significantly in pH and the content of calcium, sulfur, organic matter and THg. Conditions for methylation were more favorable in the upland forest sites compared to streamside sites. Significant bioaccumulation of THg occurred in all measured components of the food web, including insects, spiders, salamanders, and birds. Trophic position, as determined by δ15N, was the best predictor of both THg and MeHg bioaccumulation across the sampled taxa and was also a better predictor than spatial location. However, the degree of bioaccumulation at which MeHg significantly affects animal behavior, reproduction or survival is unknown for most taxa in terrestrial habitats, particularly for invertebrates. These findings show that Hg methylation and bioaccumulation is not limited to areas traditionally classified as wetlands or to areas with exceptionally high THg inputs, but that it is a widespread and important phenomenon in the moist deciduous forests of eastern North America.
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Affiliation(s)
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | | | | | - Michael S Bank
- Department of Environmental Conservation, University of Massachusetts, Amherst, MA, USA; Institute of Marine Research, Postboks 1870, Nordnes 5817, Bergen, Norway
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19
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Lowe WH, Addis BR. Matching habitat choice and plasticity contribute to phenotype–environment covariation in a stream salamander. Ecology 2019; 100:e02661. [DOI: 10.1002/ecy.2661] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/07/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Winsor H. Lowe
- Division of Biological Sciences University of Montana Missoula Montana 59812 USA
| | - Brett R. Addis
- Division of Biological Sciences University of Montana Missoula Montana 59812 USA
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20
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21
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Kovach RP, Hand BK, Hohenlohe PA, Cosart TF, Boyer MC, Neville HH, Muhlfeld CC, Amish SJ, Carim K, Narum SR, Lowe WH, Allendorf FW, Luikart G. Vive la résistance: genome-wide selection against introduced alleles in invasive hybrid zones. Proc Biol Sci 2017; 283:rspb.2016.1380. [PMID: 27881749 DOI: 10.1098/rspb.2016.1380] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/25/2016] [Indexed: 12/11/2022] Open
Abstract
Evolutionary and ecological consequences of hybridization between native and invasive species are notoriously complicated because patterns of selection acting on non-native alleles can vary throughout the genome and across environments. Rapid advances in genomics now make it feasible to assess locus-specific and genome-wide patterns of natural selection acting on invasive introgression within and among natural populations occupying diverse environments. We quantified genome-wide patterns of admixture across multiple independent hybrid zones of native westslope cutthroat trout and invasive rainbow trout, the world's most widely introduced fish, by genotyping 339 individuals from 21 populations using 9380 species-diagnostic loci. A significantly greater proportion of the genome appeared to be under selection favouring native cutthroat trout (rather than rainbow trout), and this pattern was pervasive across the genome (detected on most chromosomes). Furthermore, selection against invasive alleles was consistent across populations and environments, even in those where rainbow trout were predicted to have a selective advantage (warm environments). These data corroborate field studies showing that hybrids between these species have lower fitness than the native taxa, and show that these fitness differences are due to selection favouring many native genes distributed widely throughout the genome.
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Affiliation(s)
- Ryan P Kovach
- Northern Rocky Mountain Science Center, US Geological Survey, Missoula, MT 59802, USA
| | - Brian K Hand
- Flathead Biological Station, University of Montana, Polson, MT 59860, USA
| | - Paul A Hohenlohe
- Institute for Bioinformatics and Evolutionary Studies, Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Ted F Cosart
- Flathead Biological Station, University of Montana, Polson, MT 59860, USA.,Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | | | | | - Clint C Muhlfeld
- Northern Rocky Mountain Science Center, US Geological Survey, Missoula, MT 59802, USA.,Flathead Biological Station, University of Montana, Polson, MT 59860, USA
| | - Stephen J Amish
- Flathead Biological Station, University of Montana, Polson, MT 59860, USA.,Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Kellie Carim
- Wildlife Biology Program, University of Montana, Missoula, MT 59812, USA
| | - Shawn R Narum
- Hagerman Genetics Laboratory, Columbia River Inter-Tribal Fish Commission, Hagerman, ID 83332, USA
| | - Winsor H Lowe
- Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Fred W Allendorf
- Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Gordon Luikart
- Flathead Biological Station, University of Montana, Polson, MT 59860, USA.,Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT, USA
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22
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Kovach RP, Muhlfeld CC, Al-Chokhachy R, Amish SJ, Kershner JL, Leary RF, Lowe WH, Luikart G, Matson P, Schmetterling DA, Shepard BB, Westley PAH, Whited D, Whiteley A, Allendorf FW. No evidence for ecological segregation protecting native trout from invasive hybridization. Glob Chang Biol 2017; 23:e11-e12. [PMID: 28741850 DOI: 10.1111/gcb.13825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 06/12/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Ryan P Kovach
- Northern Rocky Mountain Science Center, U.S. Geological Survey, West Glacier, MT, USA
| | - Clint C Muhlfeld
- Northern Rocky Mountain Science Center, U.S. Geological Survey, West Glacier, MT, USA
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | - Robert Al-Chokhachy
- Northern Rocky Mountain Science Center, U.S. Geological Survey, Bozeman, MT, USA
| | - Stephen J Amish
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | - Jeffrey L Kershner
- Northern Rocky Mountain Science Center, U.S. Geological Survey, Bozeman, MT, USA
| | - Robb F Leary
- Montana, Fish, Wildlife and Parks, Missoula, MT, USA
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Gordon Luikart
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | - Phil Matson
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | | | | | - Peter A H Westley
- College of Fisheries and Ocean Sciences, University of Alaska, Fairbanks, AK, USA
| | - Diane Whited
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | - Andrew Whiteley
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - Fred W Allendorf
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
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23
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Muhlfeld CC, Kovach RP, Al-Chokhachy R, Amish SJ, Kershner JL, Leary RF, Lowe WH, Luikart G, Matson P, Schmetterling DA, Shepard BB, Westley PAH, Whited D, Whiteley A, Allendorf FW. Legacy introductions and climatic variation explain spatiotemporal patterns of invasive hybridization in a native trout. Glob Chang Biol 2017; 23:4663-4674. [PMID: 28374524 DOI: 10.1111/gcb.13681] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 02/24/2017] [Accepted: 02/28/2017] [Indexed: 06/07/2023]
Abstract
Hybridization between invasive and native species, a significant threat to worldwide biodiversity, is predicted to increase due to climate-induced expansions of invasive species. Long-term research and monitoring are crucial for understanding the ecological and evolutionary processes that modulate the effects of invasive species. Using a large, multidecade genetics dataset (N = 582 sites, 12,878 individuals) with high-resolution climate predictions and extensive stocking records, we evaluate the spatiotemporal dynamics of hybridization between native cutthroat trout and invasive rainbow trout, the world's most widely introduced invasive fish, across the Northern Rocky Mountains of the United States. Historical effects of stocking and contemporary patterns of climatic variation were strongly related to the spread of hybridization across space and time. The probability of occurrence, extent of, and temporal changes in hybridization increased at sites in close proximity to historical stocking locations with greater rainbow trout propagule pressure, warmer water temperatures, and lower spring precipitation. Although locations with warmer water temperatures were more prone to hybridization, cold sites were not protected from invasion; 58% of hybridized sites had cold mean summer water temperatures (<11°C). Despite cessation of stocking over 40 years ago, hybridization increased over time at half (50%) of the locations with long-term data, the vast majority of which (74%) were initially nonhybridized, emphasizing the chronic, negative impacts of human-mediated hybridization. These results show that effects of climate change on biodiversity must be analyzed in the context of historical human impacts that set ecological and evolutionary trajectories.
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Affiliation(s)
- Clint C Muhlfeld
- Northern Rocky Mountain Science Center, U.S. Geological Survey, West Glacier, MT, USA
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | - Ryan P Kovach
- Northern Rocky Mountain Science Center, U.S. Geological Survey, West Glacier, MT, USA
| | - Robert Al-Chokhachy
- Northern Rocky Mountain Science Center, U.S. Geological Survey, Bozeman, MT, USA
| | - Stephen J Amish
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | - Jeffrey L Kershner
- Northern Rocky Mountain Science Center, U.S. Geological Survey, Bozeman, MT, USA
| | - Robb F Leary
- Montana Fish, Wildlife and Parks, Missoula, MT, USA
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Gordon Luikart
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | - Phil Matson
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | | | | | - Peter A H Westley
- School of Fisheries and Ocean Sciences, University of Alaska, Fairbanks, AK, USA
| | - Diane Whited
- Flathead Lake Biological Station, Division of Biological Sciences, University of Montana, Polson, MT, USA
| | - Andrew Whiteley
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - Fred W Allendorf
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
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24
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Affiliation(s)
- William R. Fields
- U.S. Geological Survey Patuxent Wildlife Research Center S.O. Conte Anadromous Fish Research Center Turners Falls Massachusetts 01376 USA
| | - Evan H. Campbell Grant
- U.S. Geological Survey Patuxent Wildlife Research Center S.O. Conte Anadromous Fish Research Center Turners Falls Massachusetts 01376 USA
| | - Winsor H. Lowe
- Division of Biological Sciences University of Montana Missoula Montana 59812 USA
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25
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Hauer FR, Locke H, Dreitz VJ, Hebblewhite M, Lowe WH, Muhlfeld CC, Nelson CR, Proctor MF, Rood SB. Gravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes. Sci Adv 2016; 2:e1600026. [PMID: 27386570 PMCID: PMC4928937 DOI: 10.1126/sciadv.1600026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 05/27/2016] [Indexed: 05/10/2023]
Abstract
Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologic-altering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth.
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Affiliation(s)
- F. Richard Hauer
- Center for Integrated Research on the Environment, University of Montana, Missoula, MT 59812, USA
- Flathead Lake Biological Station, University of Montana, Polson, MT 59860, USA
- Corresponding author.
| | - Harvey Locke
- Yellowstone to Yukon Conservation Initiative, Box 4887, Banff, Alberta T1L 1G1, Canada
| | - Victoria J. Dreitz
- Wildlife Biology Program, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA
| | - Mark Hebblewhite
- Wildlife Biology Program, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA
- Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA
| | - Winsor H. Lowe
- Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Clint C. Muhlfeld
- Flathead Lake Biological Station, University of Montana, Polson, MT 59860, USA
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT 59936, USA
| | - Cara R. Nelson
- Department of Ecosystem and Conservation Sciences, College of Forestry and Conservation, University of Montana, Missoula, MT 59812, USA
| | - Michael F. Proctor
- Birchdale Ecological, PO Box 606, Kaslo, British Columbia V0G 1M0, Canada
| | - Stewart B. Rood
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta T1K 6T5, Canada
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26
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Affiliation(s)
- R. Ken Honeycutt
- Wildlife Biology Program; University of Montana, 32 Campus Drive; Missoula MT 59812 USA
| | - Winsor H. Lowe
- Division of Biological Sciences; University of Montana, 32 Campus Drive; Missoula MT 59812 USA
| | - Blake R. Hossack
- U.S. Geological Survey; Northern Rocky Mountain Science Center, Aldo Leopold Wilderness Research Institute, 790 E. Beckwith Avenue; Missoula MT 59801 USA
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27
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Kovach RP, Luikart G, Lowe WH, Boyer MC, Muhlfeld CC. Risk and efficacy of human-enabled interspecific hybridization for climate-change adaptation: response to Hamilton and Miller (2016). Conserv Biol 2016; 30:428-430. [PMID: 26918487 DOI: 10.1111/cobi.12678] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/19/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Ryan P Kovach
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park West Glacier, MT, 59936, U.S.A
| | - Gordon Luikart
- Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, U.S.A
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, U.S.A
| | | | - Clint C Muhlfeld
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park West Glacier, MT, 59936, U.S.A
- Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, U.S.A
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Crook DA, Lowe WH, Allendorf FW, Erős T, Finn DS, Gillanders BM, Hadwen WL, Harrod C, Hermoso V, Jennings S, Kilada RW, Nagelkerken I, Hansen MM, Page TJ, Riginos C, Fry B, Hughes JM. Human effects on ecological connectivity in aquatic ecosystems: Integrating scientific approaches to support management and mitigation. Sci Total Environ 2015; 534:52-64. [PMID: 25917446 DOI: 10.1016/j.scitotenv.2015.04.034] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 03/30/2015] [Accepted: 04/10/2015] [Indexed: 06/04/2023]
Abstract
Understanding the drivers and implications of anthropogenic disturbance of ecological connectivity is a key concern for the conservation of biodiversity and ecosystem processes. Here, we review human activities that affect the movements and dispersal of aquatic organisms, including damming of rivers, river regulation, habitat loss and alteration, human-assisted dispersal of organisms and climate change. Using a series of case studies, we show that the insight needed to understand the nature and implications of connectivity, and to underpin conservation and management, is best achieved via data synthesis from multiple analytical approaches. We identify four key knowledge requirements for progressing our understanding of the effects of anthropogenic impacts on ecological connectivity: autecology; population structure; movement characteristics; and environmental tolerance/phenotypic plasticity. Structuring empirical research around these four broad data requirements, and using this information to parameterise appropriate models and develop management approaches, will allow for mitigation of the effects of anthropogenic disturbance on ecological connectivity in aquatic ecosystems.
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Affiliation(s)
- David A Crook
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory 0909, Australia.
| | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | | | - Tibor Erős
- Balaton Limnological Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Tihany, Klebelsberg, K.u. 3., H-8237, Hungary
| | - Debra S Finn
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA; Departamento de Recursos Hídricos y Ciencias Ambientales, Universidad de Cuenca, Cuenca, Ecuador
| | - Bronwyn M Gillanders
- Southern Seas Ecology Laboratories, School of Biological Sciences and The Environment Institute, DX 650 418, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Wade L Hadwen
- Australian Rivers Institute, Griffith University, Nathan, QLD 4111, Australia
| | - Chris Harrod
- Instituto de Ciencias Naturales Alexander Von Humboldt, Universidad de Antofagasta, Avenida Angamos, 601 Antofagasta, Chile
| | - Virgilio Hermoso
- Australian Rivers Institute, Griffith University, Nathan, QLD 4111, Australia
| | - Simon Jennings
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Lowestoft Laboratory, Lowestoft NR33 0HT, UK; School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Raouf W Kilada
- Biology Department, University of New Brunswick (Saint John), Canada
| | - Ivan Nagelkerken
- Southern Seas Ecology Laboratories, School of Biological Sciences and The Environment Institute, DX 650 418, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Michael M Hansen
- Department of Bioscience, Aarhus University, Ny Munkegade, Bldg. 1540, DK-8000 Aarhus C, Denmark
| | - Timothy J Page
- Australian Rivers Institute, Griffith University, Nathan, QLD 4111, Australia
| | - Cynthia Riginos
- School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Brian Fry
- Australian Rivers Institute, Griffith University, Nathan, QLD 4111, Australia
| | - Jane M Hughes
- Australian Rivers Institute, Griffith University, Nathan, QLD 4111, Australia
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Kovach RP, Muhlfeld CC, Boyer MC, Lowe WH, Allendorf FW, Luikart G. Dispersal and selection mediate hybridization between a native and invasive species. Proc Biol Sci 2015; 282:20142454. [PMID: 25473019 DOI: 10.1098/rspb.2014.2454] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hybridization between native and non-native species has serious biological consequences, but our understanding of how dispersal and selection interact to influence invasive hybridization is limited. Here, we document the spread of genetic introgression between a native (Oncorhynchus clarkii) and invasive (Oncorhynchus mykiss) trout, and identify the mechanisms influencing genetic admixture. In two populations inhabiting contrasting environments, non-native admixture increased rapidly from 1984 to 2007 and was driven by surprisingly consistent processes. Individual admixture was related to two phenotypic traits associated with fitness: size at spawning and age of juvenile emigration. Fish with higher non-native admixture were larger and tended to emigrate at a younger age--relationships that are expected to confer fitness advantages to hybrid individuals. However, strong selection against non-native admixture was evident across streams and cohorts (mean selection coefficient against genotypes with non-native alleles (s) = 0.60; s.e. = 0.10). Nevertheless, hybridization was promoted in both streams by the continuous immigration of individuals with high levels of non-native admixture from other hybrid source populations. Thus, antagonistic relationships between dispersal and selection are mediating invasive hybridization between these fish, emphasizing that data on dispersal and natural selection are needed to fully understand the dynamics of introgression between native and non-native species.
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Affiliation(s)
- Ryan P Kovach
- US Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT 59936, USA Flathead Lake Biological Station, Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Polson, MT 59860, USA
| | - Clint C Muhlfeld
- US Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT 59936, USA
| | | | - Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Fred W Allendorf
- Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Gordon Luikart
- Flathead Lake Biological Station, Fish and Wildlife Genomics Group, Division of Biological Sciences, University of Montana, Polson, MT 59860, USA
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30
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Hand BK, Lowe WH, Kovach RP, Muhlfeld CC, Luikart G. Landscape community genomics: understanding eco-evolutionary processes in complex environments. Trends Ecol Evol 2015; 30:161-8. [DOI: 10.1016/j.tree.2015.01.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 10/24/2022]
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31
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Addis BR, Lowe WH, Hossack BR, Allendorf FW. Population genetic structure and disease in montane boreal toads: more heterozygous individuals are more likely to be infected with amphibian chytrid. CONSERV GENET 2015. [DOI: 10.1007/s10592-015-0704-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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32
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Hand BK, Hether TD, Kovach RP, Muhlfeld CC, Amish SJ, Boyer MC, O’rourke SM, Miller MR, Lowe WH, Hohenlohe PA, Luikart G. Genomics and introgression: Discovery and mapping of thousands of species-diagnostic SNPs using RAD sequencing. Curr Zool 2015. [DOI: 10.1093/czoolo/61.1.146] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Invasive hybridization and introgression pose a serious threat to the persistence of many native species. Understanding the effects of hybridization on native populations (e.g., fitness consequences) requires numerous species-diagnostic loci distributed genome-wide. Here we used RAD sequencing to discover thousands of single-nucleotide polymorphisms (SNPs) that are diagnostic between rainbow trout (RBT, Oncorhynchus mykiss), the world’s most widely introduced fish, and native westslope cutthroat trout (WCT, O. clarkii lewisi) in the northern Rocky Mountains, USA. We advanced previous work that identified 4,914 species-diagnostic loci by using longer sequence reads (100 bp vs. 60 bp) and a larger set of individuals (n = 84). We sequenced RAD libraries for individuals from diverse sampling sources, including native populations of WCT and hatchery broodstocks of WCT and RBT. We also took advantage of a newly released reference genome assembly for RBT to align our RAD loci. In total, we discovered 16,788 putatively diagnostic SNPs, 10,267 of which we mapped to anchored chromosome locations on the RBT genome. A small portion of previously discovered putative diagnostic loci (325 of 4,914) were no longer diagnostic (i.e., fixed between species) based on our wider survey of non-hybridized RBT and WCT individuals. Our study suggests that RAD loci mapped to a draft genome assembly could provide the marker density required to identify genes and chromosomal regions influencing selection in admixed populations of conservation concern and evolutionary interest.
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Affiliation(s)
- Brian K. Hand
- Flathead Lake Biological Station, Fish and Wildlife Genomics Group, University of Montana, Polson, MT 59860, USA
| | - Tyler D. Hether
- Institute for Bioinformatics and Evolutionary Studies, Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Ryan P. Kovach
- Flathead Lake Biological Station, Fish and Wildlife Genomics Group, University of Montana, Polson, MT 59860, USA
- U. S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, Montana 59936, USA
| | - Clint C. Muhlfeld
- U. S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, Montana 59936, USA
| | - Stephen J. Amish
- Fish and Wildlife Genomics Group, Division of Biological Sciences, The University of Montana, Missoula, Montana 59812, USA
| | | | - Sean M. O’rourke
- Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Michael R. Miller
- Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Winsor H. Lowe
- University of Montana, Division of Biological Sciences, Missoula, Montana 59812, USA
| | - Paul A. Hohenlohe
- Institute for Bioinformatics and Evolutionary Studies, Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Gordon Luikart
- Flathead Lake Biological Station, Fish and Wildlife Genomics Group, University of Montana, Polson, MT 59860, USA
- Institute for Bioinformatics and Evolutionary Studies, Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
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33
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Davenport JM, Hossack BR, Lowe WH. Partitioning the non-consumptive effects of predators on prey with complex life histories. Oecologia 2014; 176:149-55. [DOI: 10.1007/s00442-014-2996-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 06/09/2014] [Indexed: 11/29/2022]
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34
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Jane SF, Wilcox TM, McKelvey KS, Young MK, Schwartz MK, Lowe WH, Letcher BH, Whiteley AR. Distance, flow and PCR inhibition: eDNA dynamics in two headwater streams. Mol Ecol Resour 2014; 15:216-27. [PMID: 24890199 DOI: 10.1111/1755-0998.12285] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/16/2014] [Accepted: 05/21/2014] [Indexed: 11/27/2022]
Abstract
Environmental DNA (eDNA) detection has emerged as a powerful tool for monitoring aquatic organisms, but much remains unknown about the dynamics of aquatic eDNA over a range of environmental conditions. DNA concentrations in streams and rivers will depend not only on the equilibrium between DNA entering the water and DNA leaving the system through degradation, but also on downstream transport. To improve understanding of the dynamics of eDNA concentration in lotic systems, we introduced caged trout into two fishless headwater streams and took eDNA samples at evenly spaced downstream intervals. This was repeated 18 times from mid-summer through autumn, over flows ranging from approximately 1-96 L/s. We used quantitative PCR to relate DNA copy number to distance from source. We found that regardless of flow, there were detectable levels of DNA at 239.5 m. The main effect of flow on eDNA counts was in opposite directions in the two streams. At the lowest flows, eDNA counts were highest close to the source and quickly trailed off over distance. At the highest flows, DNA counts were relatively low both near and far from the source. Biomass was positively related to eDNA copy number in both streams. A combination of cell settling, turbulence and dilution effects is probably responsible for our observations. Additionally, during high leaf deposition periods, the presence of inhibitors resulted in no amplification for high copy number samples in the absence of an inhibition-releasing strategy, demonstrating the necessity to carefully consider inhibition in eDNA analysis.
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Affiliation(s)
- Stephen F Jane
- Department of Environmental Conservation, University of Massachusetts, Amherst, MA, 01003, USA
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35
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Landguth EL, Muhlfeld CC, Waples RS, Jones L, Lowe WH, Whited D, Lucotch J, Neville H, Luikart G. Combining demographic and genetic factors to assess population vulnerability in stream species. Ecol Appl 2014; 24:1505-1524. [PMID: 29160670 DOI: 10.1890/13-0499.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Accelerating climate change and other cumulative stressors create an urgent need to understand the influence of environmental variation and landscape features on the connectivity and vulnerability of freshwater species. Here, we introduce a novel modeling framework for aquatic systems that integrates spatially explicit, individual-based, demographic and genetic (demogenetic) assessments with environmental variables. To show its potential utility, we simulated a hypothetical network of 19 migratory riverine populations (e.g., salmonids) using a riverscape connectivity and demogenetic model (CDFISH). We assessed how stream resistance to movement (a function of water temperature, fluvial distance, and physical barriers) might influence demogenetic connectivity, and hence, population vulnerability. We present demographic metrics (abundance, immigration, and change in abundance) and genetic metrics (diversity, differentiation, and change in differentiation), and combine them into a single vulnerability index for identifying populations at risk of extirpation. We considered four realistic scenarios that illustrate the relative sensitivity of these metrics for early detection of reduced connectivity: (1) maximum resistance due to high water temperatures throughout the network, (2) minimum resistance due to low water temperatures throughout the network, (3) increased resistance at a tributary junction caused by a partial barrier, and (4) complete isolation of a tributary, leaving resident individuals only. We then applied this demogenetic framework using empirical data for a bull trout (Salvelinus confluentus) metapopulation in the upper Flathead River system, Canada and USA, to assess how current and predicted future stream warming may influence population vulnerability. Results suggest that warmer water temperatures and associated barriers to movement (e.g., low flows, dewatering) are predicted to fragment suitable habitat for migratory salmonids, resulting in the loss of genetic diversity and reduced numbers in certain vulnerable populations. This demogenetic simulation framework, which is illustrated in a web-based interactive mapping prototype, should be useful for evaluating population vulnerability in a wide variety of dendritic and fragmented riverscapes, helping to guide conservation and management efforts for freshwater species.
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Wilcox TM, McKelvey KS, Young MK, Jane SF, Lowe WH, Whiteley AR, Schwartz MK. Robust detection of rare species using environmental DNA: the importance of primer specificity. PLoS One 2013; 8:e59520. [PMID: 23555689 PMCID: PMC3608683 DOI: 10.1371/journal.pone.0059520] [Citation(s) in RCA: 215] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/15/2013] [Indexed: 11/18/2022] Open
Abstract
Environmental DNA (eDNA) is being rapidly adopted as a tool to detect rare animals. Quantitative PCR (qPCR) using probe-based chemistries may represent a particularly powerful tool because of the method’s sensitivity, specificity, and potential to quantify target DNA. However, there has been little work understanding the performance of these assays in the presence of closely related, sympatric taxa. If related species cause any cross-amplification or interference, false positives and negatives may be generated. These errors can be disastrous if false positives lead to overestimate the abundance of an endangered species or if false negatives prevent detection of an invasive species. In this study we test factors that influence the specificity and sensitivity of TaqMan MGB assays using co-occurring, closely related brook trout (Salvelinus fontinalis) and bull trout (S. confluentus) as a case study. We found qPCR to be substantially more sensitive than traditional PCR, with a high probability of detection at concentrations as low as 0.5 target copies/µl. We also found that number and placement of base pair mismatches between the Taqman MGB assay and non-target templates was important to target specificity, and that specificity was most influenced by base pair mismatches in the primers, rather than in the probe. We found that insufficient specificity can result in both false positive and false negative results, particularly in the presence of abundant related species. Our results highlight the utility of qPCR as a highly sensitive eDNA tool, and underscore the importance of careful assay design.
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Affiliation(s)
- Taylor M Wilcox
- United States Department of Agriculture Forest Service, Rocky Mountain Research Station, Missoula, Montana, United States of America.
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37
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Hossack BR, Lowe WH, Honeycutt RK, Parks SA, Corn PS. Interactive effects of wildfire, forest management, and isolation on amphibian and parasite abundance. Ecol Appl 2013; 23:479-492. [PMID: 23634596 DOI: 10.1890/12-0316.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Projected increases in wildfire and other climate-driven disturbances will affect populations and communities worldwide, including host-parasite relationships. Research in temperate forests has shown that wildfire can negatively affect amphibians, but this research has occurred primarily outside of managed landscapes where interactions with human disturbances could result in additive or synergistic effects. Furthermore, parasites represent a large component of biodiversity and can affect host fitness and population dynamics, yet they are rarely included in studies of how vertebrate hosts respond to disturbance. To determine how wildfire affects amphibians and their parasites, and whether effects differ between protected and managed landscapes, we compared abundance of two amphibians and two nematodes relative to wildfire extent and severity around wetlands in neighboring protected and managed forests (Montana, USA). Population sizes of adult, male long-toed salamanders (Ambystoma macrodactylum) decreased with increased burn severity, with stronger negative effects on isolated populations and in managed forests. In contrast, breeding population sizes of Columbia spotted frogs (Rana luteiventris) increased with burn extent in both protected and managed protected forests. Path analysis showed that the effects of wildfire on the two species of nematodes were consistent with differences in their life history and transmission strategies and the responses of their hosts. Burn severity indirectly reduced abundance of soil-transmitted Cosmocercoides variabilis through reductions in salamander abundance. Burn severity also directly reduced C. variabilis abundance, possibly though changes in soil conditions. For the aquatically transmitted nematode Gyrinicola batrachiensis, the positive effect of burn extent on density of Columbia spotted frog larvae indirectly increased parasite abundance. Our results show that effects of wildfire on amphibians depend upon burn extent and severity, isolation, and prior land use. Through subsequent effects on the parasites, our results also reveal how changes in disturbance regimes can affect communities across trophic levels.
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Affiliation(s)
- Blake R Hossack
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Aldo Leopold Wilderness Research Institute, 790 East Beckwith Avenue, Missoula, Montana 59801, USA.
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Hossack BR, Lowe WH, Corn PS. Rapid increases and time-lagged declines in amphibian occupancy after wildfire. Conserv Biol 2013; 27:219-228. [PMID: 22978248 DOI: 10.1111/j.1523-1739.2012.01921.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 05/20/2012] [Indexed: 06/01/2023]
Abstract
Climate change is expected to increase the frequency and severity of drought and wildfire. Aquatic and moisture-sensitive species, such as amphibians, may be particularly vulnerable to these modified disturbance regimes because large wildfires often occur during extended droughts and thus may compound environmental threats. However, understanding of the effects of wildfires on amphibians in forests with long fire-return intervals is limited. Numerous stand-replacing wildfires have occurred since 1988 in Glacier National Park (Montana, U.S.A.), where we have conducted long-term monitoring of amphibians. We measured responses of 3 amphibian species to fires of different sizes, severity, and age in a small geographic area with uniform management. We used data from wetlands associated with 6 wildfires that burned between 1988 and 2003 to evaluate whether burn extent and severity and interactions between wildfire and wetland isolation affected the distribution of breeding populations. We measured responses with models that accounted for imperfect detection to estimate occupancy during prefire (0-4 years) and different postfire recovery periods. For the long-toed salamander (Ambystoma macrodactylum) and Columbia spotted frog (Rana luteiventris), occupancy was not affected for 6 years after wildfire. But 7-21 years after wildfire, occupancy for both species decreased ≥ 25% in areas where >50% of the forest within 500 m of wetlands burned. In contrast, occupancy of the boreal toad (Anaxyrus boreas) tripled in the 3 years after low-elevation forests burned. This increase in occupancy was followed by a gradual decline. Our results show that accounting for magnitude of change and time lags is critical to understanding population dynamics of amphibians after large disturbances. Our results also inform understanding of the potential threat of increases in wildfire frequency or severity to amphibians in the region.
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Affiliation(s)
- Blake R Hossack
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Aldo Leopold Wilderness Research Institute, 790 East Beckwith Avenue, Missoula, MT 59801, USA
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39
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Affiliation(s)
- Winsor H Lowe
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA.
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40
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Cosentino BJ, Phillips CA, Schooley RL, Lowe WH, Douglas MR. Linking extinction-colonization dynamics to genetic structure in a salamander metapopulation. Proc Biol Sci 2011; 279:1575-82. [PMID: 22113029 DOI: 10.1098/rspb.2011.1880] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Theory predicts that founder effects have a primary role in determining metapopulation genetic structure. However, ecological factors that affect extinction-colonization dynamics may also create spatial variation in the strength of genetic drift and migration. We tested the hypothesis that ecological factors underlying extinction-colonization dynamics influenced the genetic structure of a tiger salamander (Ambystoma tigrinum) metapopulation. We used empirical data on metapopulation dynamics to make a priori predictions about the effects of population age and ecological factors on genetic diversity and divergence among 41 populations. Metapopulation dynamics of A. tigrinum depended on wetland area, connectivity and presence of predatory fish. We found that newly colonized populations were more genetically differentiated than established populations, suggesting that founder effects influenced genetic structure. However, ecological drivers of metapopulation dynamics were more important than age in predicting genetic structure. Consistent with demographic predictions from metapopulation theory, genetic diversity and divergence depended on wetland area and connectivity. Divergence was greatest in small, isolated wetlands where genetic diversity was low. Our results show that ecological factors underlying metapopulation dynamics can be key determinants of spatial genetic structure, and that habitat area and isolation may mediate the contributions of drift and migration to divergence and evolution in local populations.
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Affiliation(s)
- Bradley J Cosentino
- Program in Ecology, Evolution and Conservation Biology, University of Illinois, Urbana, IL 61801, USA.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Abstract
Long-distance dispersal (LDD) may contribute disproportionately to range expansions, the creation of new evolutionary lineages, and species persistence in human-dominated landscapes. However, because data on the individual consequences of dispersal distance are extremely limited, we have little insight on how LDD is maintained in natural populations. I used six years of spatially explicit capture-mark-recapture (CMR) data to test the prediction that individual performance increases with dispersal distance in the stream salamander Gyrinophilus porphyriticus. Dispersal distance was total distance moved along the 1-km study stream, ranging from 0 to 565 m. To quantify individual performance, I used CMR estimates of survival and individual growth rates based on change in body length. Survival and growth rates increased significantly with dispersal distance. These relationships were not confounded by pre-dispersal body condition or by ecological gradients along the stream. Individual benefits of LDD were likely caused by an increase in the upper limit of settlement site quality with dispersal distance. My results do not support the view that the fitness consequences of LDD are unpredictable and instead suggest that consistent evolutionary mechanisms may explain the prevalence of LDD in nature. They also highlight the value of direct CMR data for understanding the individual consequences of variation in dispersal distance and how that variation is maintained in natural populations.
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Affiliation(s)
- Winsor H Lowe
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA.
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Campbell Grant EH, Nichols JD, Lowe WH, Fagan WF. Use of multiple dispersal pathways facilitates amphibian persistence in stream networks. Proc Natl Acad Sci U S A 2010; 107:6936-40. [PMID: 20351269 PMCID: PMC2872445 DOI: 10.1073/pnas.1000266107] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although populations of amphibians are declining worldwide, there is no evidence that salamanders occupying small streams are experiencing enigmatic declines, and populations of these species seem stable. Theory predicts that dispersal through multiple pathways can stabilize populations, preventing extinction in habitat networks. However, empirical data to support this prediction are absent for most species, especially those at risk of decline. Our mark-recapture study of stream salamanders reveals both a strong upstream bias in dispersal and a surprisingly high rate of overland dispersal to adjacent headwater streams. This evidence of route-dependent variation in dispersal rates suggests a spatial mechanism for population stability in headwater-stream salamanders. Our results link the movement behavior of stream salamanders to network topology, and they underscore the importance of identifying and protecting critical dispersal pathways when addressing region-wide population declines.
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Affiliation(s)
- Evan H Campbell Grant
- Northeast Amphibian Research and Monitoring Initiative, US Geological Survey Patuxent Wildlife Research Center, Laurel, MD 20708-4026, USA.
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Abstract
Spatial structure regulates and modifies processes at several levels of ecological organization (e.g. individual/genetic, population and community) and is thus a key component of complex systems, where knowledge at a small scale can be insufficient for understanding system behaviour at a larger scale. Recent syntheses outline potential applications of network theory to ecological systems, but do not address the implications of physical structure for network dynamics. There is a specific need to examine how dendritic habitat structure, such as that found in stream, hedgerow and cave networks, influences ecological processes. Although dendritic networks are one type of ecological network, they are distinguished by two fundamental characteristics: (1) both the branches and the nodes serve as habitat, and (2) the specific spatial arrangement and hierarchical organization of these elements interacts with a species' movement behaviour to alter patterns of population distribution and abundance, and community interactions. Here, we summarize existing theory relating to ecological dynamics in dendritic networks, review empirical studies examining the population- and community-level consequences of these networks, and suggest future research integrating spatial pattern and processes in dendritic systems.
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Affiliation(s)
- Evan H Campbell Grant
- USGS--Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, MD 20708, USA.
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Abstract
There is growing recognition of the need to incorporate information on movement behavior in landscape-scale studies of dispersal. One way to do this is by using indirect indices of dispersal (e.g., genetic differentiation) to test predictions derived from direct data on movement behavior. Mark-recapture studies documented upstream-biased movement in the salamander Gyrinophilus porphyriticus (Plethodontidae). Based on this information, we hypothesized that gene flow in G. porphyriticus is affected by the slope of the stream. Specifically, because the energy required for upstream dispersal is positively related to slope, we predicted gene flow to be negatively related to change in elevation between sampling sites. Using amplified DNA fragment length polymorphisms among tissue samples from paired sites in nine streams in the Hubbard Brook Watershed, New Hampshire, USA, we found that genetic distances between downstream and upstream sites were positively related to change in elevation over standardized 1-km distances. This pattern of isolation by slope elucidates controls on population connectivity in stream networks and underscores the potential for specific behaviors to affect the genetic structure of species at the landscape scale. More broadly, our results show the value of combining direct data on movement behavior and indirect indices to assess patterns and consequences of dispersal in spatially complex ecosystems.
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Affiliation(s)
- Winsor H Lowe
- Institute of Ecosystem Studies, Millbrook, New York, New York 12545, USA.
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50
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Abstract
The movement of individuals among populations can be critical in preventing local and landscape-scale species extinctions in systems exposed to human perturbation. Current understanding of spatial population dynamics in streams is largely limited to the reach scale and is therefore inadequate to address species response to spatially extensive perturbation. Using model simulations, I examined species response to perturbation in a drainage composed of multiple, hierarchically arranged stream-patches connected by in-stream and overland pathways of dispersal. Patch extinction probability, the proportion of initially occupied patches extinct after 25 years, was highly sensitive to the extent of species occupancy and perturbation within the drainage, longitudinal species distribution, perturbation decay rate and the covariance pattern of stochastic effects on colonization and extinction probabilities. Results of these simulations underscore the importance of identifying and preserving source populations and dispersal routes for stream species in human-impacted landscapes. They also highlight the vulnerability of headwater specialist taxa to anthropogenic perturbation, and the strong positive effect on species resilience of habitat rehabilitation when recolonization is possible. Efforts to conserve and manage stream species may be greatly improved by accounting for landscape-scale spatial population dynamics.
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Affiliation(s)
- Winsor H Lowe
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755-3577, USA.
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