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Chandler HC, Colón-Gaud JC, Gorman TA, Carson K, Haas CA. Does long-term fire suppression impact leaf litter breakdown and aquatic invertebrate colonization in pine flatwoods wetlands? PeerJ 2021; 9:e12534. [PMID: 34909276 PMCID: PMC8638572 DOI: 10.7717/peerj.12534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 08/24/2021] [Accepted: 11/02/2021] [Indexed: 11/20/2022] Open
Abstract
Ephemeral wetlands are commonly embedded within pine uplands of the southeastern United States. These wetlands support diverse communities but have often been degraded by a lack of growing-season fires that historically maintained the vegetation structure. In the absence of fire, wetlands develop a dense mid-story of woody vegetation that increases canopy cover and decreases the amount of herbaceous vegetation. To understand how reduced fire frequency impacts wetland processes, we measured leaf litter breakdown rates and invertebrate communities using three common plant species (Longleaf Pine (Pinus palustris), Pineland Threeawn Grass (Aristida stricta), and Black Gum (Nyssa sylvatica)) that occur in pine flatwoods wetlands located on Eglin Air Force Base, Florida. We also tested whether or not the overall habitat type within a wetland (fire maintained or fire suppressed) affected these processes. We placed leaf packs containing 15.0 g of dried leaf litter from each species in both fire-maintained and fire-suppressed sections of three wetlands, removing them after 103–104 days submerged in the wetland. The amount of leaf litter remaining at the end of the study varied across species (N. sylvatica = 7.97 ± 0.17 g, A. stricta = 11.84 ± 0.06 g, and P. palustris = 11.37 ± 0.07 g (mean ± SE)) and was greater in fire-maintained habitat (leaf type: F2,45 = 437.2, P < 0.001; habitat type: F1,45 = 4.6, P = 0.037). We identified an average of 260 ± 33.5 (SE) invertebrates per leaf pack (range: 19–1,283), and the most abundant taxonomic groups were Cladocera, Isopoda, Acariformes, and Diptera. Invertebrate relative abundance varied significantly among litter species (approximately 39.9 ± 9.4 invertebrates per gram of leaf litter remaining in N. sylvatica leaf packs, 27.2 ± 5.3 invertebrates per gram of A. stricta, and 14.6 ± 3.1 invertebrates per gram of P. palustris (mean ± SE)) but not habitat type. However, both habitat (pseudo-F1,49 = 4.30, P = 0.003) and leaf litter type (pseudo-F2,49 = 3.62, P = 0.001) had a significant effect on invertebrate community composition. Finally, this work was part of ongoing projects focusing on the conservation of the critically imperiled Reticulated Flatwoods Salamander (Ambystoma bishopi), which breeds exclusively in pine flatwoods wetlands, and we examined the results as they relate to potential prey items for larval flatwoods salamanders. Overall, our results suggest that the vegetation changes associated with a lack of growing-season fires can impact both invertebrate communities and leaf litter breakdown.
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Affiliation(s)
- Houston C Chandler
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America.,The Orianne Society, Tiger, GA, United States of America
| | - J Checo Colón-Gaud
- Department of Biology, Georgia Southern University, Statesboro, GA, United States of America
| | - Thomas A Gorman
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America.,Aquatic Resources Division, Washington State Department of Natural Resources, Olympia, WA, United States of America
| | - Khalil Carson
- Department of Biology, Georgia Southern University, Statesboro, GA, United States of America.,Biological and Environmental Sciences Department, Troy University, Troy, AL, United States of America
| | - Carola A Haas
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
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Brooks GC, Gorman TA, Jiao Y, Haas CA. Reconciling larval and adult sampling methods to model growth across life-stages. PLoS One 2020; 15:e0237737. [PMID: 32822355 PMCID: PMC7442236 DOI: 10.1371/journal.pone.0237737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 04/27/2020] [Accepted: 07/31/2020] [Indexed: 11/29/2022] Open
Abstract
Individual growth rates are intrinsically related to survival and lifetime reproductive success and hence, are key determinants of population growth. Efforts to quantify age-size relationships are hampered by difficulties in aging individuals in wild populations. In addition, species with complex life-histories often show distinct shifts in growth that cannot be readily accommodated by traditional modelling techniques. Amphibians are often characterized by rapid larval growth, cessation of growth prior to metamorphosis, and resumption of growth in the adult stage. Compounding issues of non-linear growth, amphibian monitoring programs typically sample larval and adult populations using dissimilar methods. Here we present the first multistage growth model that combines disparate data collected across life-history stages. We model the growth of the endangered Reticulated Flatwoods Salamander, Ambystoma bishopi, in a Bayesian framework, that accounts for unknown ages, individual heterogeneity, and reconciles dip-net and drift fence sampling designs. Flatwoods salamanders achieve 60% of growth in the first 3 months of life but can survive for up to 13 years as a terrestrial adult. We find evidence for marked variability in growth rate, the timing and age at metamorphosis, and maximum size, within populations. Average size of metamorphs in a given year appeared strongly dependent on hydroperiod, and differed by >10mm across years with successful recruitment. In contrast, variation in the sizes of emerging metamorphs appeared relatively constant across years. An understanding of growth will contribute to the development of population viability analyses for flatwoods salamanders, will guide management actions, and will ultimately aid the recovery of the species. Our model formulation has broad applicability to amphibians, and likely any stage-structured organism in which homogenous data cannot be collected across life-stages. The tendency to ignore stage-structure or omit non-conforming data in growth analyses can no longer be afforded given the high stakes of management decisions, particularly for endangered or at-risk populations.
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Affiliation(s)
- George C. Brooks
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
| | - Thomas A. Gorman
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Yan Jiao
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Carola A. Haas
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
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Miller DAW, Grant EHC, Muths E, Amburgey SM, Adams MJ, Joseph MB, Waddle JH, Johnson PTJ, Ryan ME, Schmidt BR, Calhoun DL, Davis CL, Fisher RN, Green DM, Hossack BR, Rittenhouse TAG, Walls SC, Bailey LL, Cruickshank SS, Fellers GM, Gorman TA, Haas CA, Hughson W, Pilliod DS, Price SJ, Ray AM, Sadinski W, Saenz D, Barichivich WJ, Brand A, Brehme CS, Dagit R, Delaney KS, Glorioso BM, Kats LB, Kleeman PM, Pearl CA, Rochester CJ, Riley SPD, Roth M, Sigafus BH. Quantifying climate sensitivity and climate-driven change in North American amphibian communities. Nat Commun 2018; 9:3926. [PMID: 30254220 PMCID: PMC6156563 DOI: 10.1038/s41467-018-06157-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 08/16/2018] [Indexed: 11/09/2022] Open
Abstract
Changing climate will impact species' ranges only when environmental variability directly impacts the demography of local populations. However, measurement of demographic responses to climate change has largely been limited to single species and locations. Here we show that amphibian communities are responsive to climatic variability, using >500,000 time-series observations for 81 species across 86 North American study areas. The effect of climate on local colonization and persistence probabilities varies among eco-regions and depends on local climate, species life-histories, and taxonomic classification. We found that local species richness is most sensitive to changes in water availability during breeding and changes in winter conditions. Based on the relationships we measure, recent changes in climate cannot explain why local species richness of North American amphibians has rapidly declined. However, changing climate does explain why some populations are declining faster than others. Our results provide important insights into how amphibians respond to climate and a general framework for measuring climate impacts on species richness.
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Affiliation(s)
- David A W Miller
- Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA, 16802, USA.
| | - Evan H Campbell Grant
- U.S. Geological Survey, Patuxent Wildlife Research Center, SO Conte Anadromous Fish Lab, 1 Migratory Way, Turners Falls, MA, 01376, USA.
| | - Erin Muths
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, 80523, USA.
| | - Staci M Amburgey
- Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA, 16802, USA
- Intercollege Graduate Ecology Program, Pennsylvania State University, University Park, PA, 16802, USA
| | - Michael J Adams
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, 97331, USA
| | - Maxwell B Joseph
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, Boulder, CO, 80309, USA
| | - J Hardin Waddle
- U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, LA, 70506, USA
| | - Pieter T J Johnson
- Ecology and Evolutionary Biology Department, University of Colorado, Boulder, Boulder, CO, 80309, USA
| | - Maureen E Ryan
- School of Environment and Forest Sciences, University of Washington, Seattle, WA, 98195, USA
- Conservation Science Partners, Seattle, WA, 98102, USA
| | - Benedikt R Schmidt
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, 8057, Switzerland
- Info Fauna Karch, 2000, Neuchâtel, Switzerland
| | - Daniel L Calhoun
- U.S. Geological Survey, South Atlantic Water Science Center, Norcross, GA, 30093, USA
| | - Courtney L Davis
- Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA, 16802, USA
- Intercollege Graduate Ecology Program, Pennsylvania State University, University Park, PA, 16802, USA
| | - Robert N Fisher
- U.S. Geological Survey, Western Ecological Research Center, San Diego, CA, 92101, USA
| | - David M Green
- Redpath Museum, McGill University, Montreal, QC, H3A 0C4, Canada
| | - Blake R Hossack
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Aldo Leopold Wilderness Research Institute, Missoula, MT, 59801, USA
| | - Tracy A G Rittenhouse
- Department of Natural Resources and the Environment, University of Connecticut, Storrs, CT, 06269, USA
| | - Susan C Walls
- U.S. Geological Survey, Wetland and Aquatic Research Center, Gainesville, FL, 32653, USA
| | - Larissa L Bailey
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Sam S Cruickshank
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, 8057, Switzerland
| | - Gary M Fellers
- U.S. Geological Survey, Western Ecological Research Center, Point Reyes Station, CA, 94956, USA
| | - Thomas A Gorman
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Carola A Haas
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, 24061, USA
| | | | - David S Pilliod
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Boise, ID, 83706, USA
| | - Steven J Price
- Department of Forestry and Natural Resources, University of Kentucky, Lexington, KY, 40506, USA
| | - Andrew M Ray
- Greater Yellowstone Network, National Park Service, Bozeman, MT, 59715, USA
| | - Walt Sadinski
- U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, WI, 54603, USA
| | - Daniel Saenz
- U. S. Department of Agriculture, Southern Research Station, Forest Service, Nacogdoches, TX, 75965, USA
| | - William J Barichivich
- U.S. Geological Survey, Wetland and Aquatic Research Center, Gainesville, FL, 32653, USA
| | - Adrianne Brand
- U.S. Geological Survey, Patuxent Wildlife Research Center, SO Conte Anadromous Fish Lab, 1 Migratory Way, Turners Falls, MA, 01376, USA
| | - Cheryl S Brehme
- U.S. Geological Survey, Western Ecological Research Center, San Diego, CA, 92101, USA
| | - Rosi Dagit
- Resource Conservation District of the Santa Monica Mountains, Topanga, CA, 90290, USA
| | - Katy S Delaney
- National Park Service-Santa Monica Mountains Recreation Area, Thousand Oaks, CA, 91360, USA
| | - Brad M Glorioso
- U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, LA, 70506, USA
| | - Lee B Kats
- Natural Sciences Division, Seaver College, Pepperdine University, Malibu, CA, 90263, USA
| | - Patrick M Kleeman
- U.S. Geological Survey, Western Ecological Research Center, Point Reyes Station, CA, 94956, USA
| | - Christopher A Pearl
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, 97331, USA
| | - Carlton J Rochester
- U.S. Geological Survey, Western Ecological Research Center, San Diego, CA, 92101, USA
| | - Seth P D Riley
- National Park Service-Santa Monica Mountains Recreation Area, Thousand Oaks, CA, 91360, USA
| | - Mark Roth
- U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, WI, 54603, USA
| | - Brent H Sigafus
- U.S. Geological Survey, Southwest Biological Science Center, Tucson, AZ, 85719, USA
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Chandler HC, Rypel AL, Jiao Y, Haas CA, Gorman TA. Hindcasting Historical Breeding Conditions for an Endangered Salamander in Ephemeral Wetlands of the Southeastern USA: Implications of Climate Change. PLoS One 2016; 11:e0150169. [PMID: 26910245 PMCID: PMC4766244 DOI: 10.1371/journal.pone.0150169] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [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: 10/26/2015] [Accepted: 02/10/2016] [Indexed: 11/18/2022] Open
Abstract
The hydroperiod of ephemeral wetlands is often the most important characteristic determining amphibian breeding success, especially for species with long development times. In mesic and wet pine flatwoods of the southeastern United States, ephemeral wetlands were a common landscape feature. Reticulated flatwoods salamanders (Ambystoma bishopi), a federally endangered species, depend exclusively on ephemeral wetlands and require at least 11 weeks to successfully metamorphose into terrestrial adults. We empirically modeled hydroperiod of 17 A. bishopi breeding wetlands by combining downscaled historical climate-model data with a recent 9-year record (2006-2014) of observed water levels. Empirical models were subsequently used to reconstruct wetland hydrologic conditions from 1896-2014 using the downscaled historical climate datasets. Reconstructed hydroperiods for the 17 wetlands were highly variable through time but were frequently unfavorable for A. bishopi reproduction (e.g., only 61% of years, using a conservative estimate of development time [12 weeks], were conducive to larval development and metamorphosis). Using change-point analysis, we identified significant shifts in average hydroperiod over the last century in all 17 wetlands. Mean hydroperiods were shorter in recent years than at any other point since 1896, and thus less suitable for A. bishopi reproduction. We suggest that climate change will continue to impact the reproductive success of flatwoods salamanders and other ephemeral wetland breeders by reducing the number of years these wetlands have suitable hydroperiods. Consequently, we emphasize the importance of conservation and management for mitigating other forms of habitat degradation, especially maintenance of high quality breeding sites where reproduction can occur during appropriate environmental conditions.
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Affiliation(s)
- Houston C. Chandler
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
| | - Andrew L. Rypel
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Yan Jiao
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Carola A. Haas
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Thomas A. Gorman
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
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