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Lopez JW, Hartnett RN, Parr TB, Vaughn CC. Ecosystem bioelement variability is associated with freshwater animal aggregations at the aquatic-terrestrial interface. Oecologia 2023; 202:795-806. [PMID: 37582947 DOI: 10.1007/s00442-023-05437-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 08/08/2023] [Indexed: 08/17/2023]
Abstract
The impacts of animals on the biogeochemical cycles of major bioelements like C, N, and P are well-studied across ecosystem types. However, more than 20 elements are necessary for life. The feedbacks between animals and the biogeochemical cycles of the other bioelements are an emerging research priority. We explored how much freshwater mussels (Bivalvia: Unionoida) were related to variability in ecosystem pools of 10 bioelements (Ca, Cu, Fe, K, Mn, Na, Mg, P, S and Zn) in streams containing a natural mussel density gradient in the US Interior Highlands. We studied the concentrations of these bioelements across the aquatic-terrestrial interface-in the porewater of riverine gravel bars, and the emergent macrophyte Justicia americana. Higher mussel density was associated with increased calcium in gravel bars and macrophytes. Mussel density also correlated with variability in iron and other redox-sensitive trace elements in gravel bars and macrophytes, although this relationship was mediated by sediment grain size. We found that two explanations for the patterns we observed are worthy of further research: (1) increased calcium availability in gravel bars near denser mussel aggregations may be a product of the buildup and dissolution of shells in the gravel bar, and (2) mussels may alter redox conditions, and thus elemental availability in gravel bars with fine sediments, either behaviorally or through physical structure provided by shell material. A better understanding of the physical and biogeochemical impacts of animals on a wide range of elemental cycles is thus necessary to conserve the societal value of freshwater ecosystems.
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Affiliation(s)
- Jonathan W Lopez
- Department of Biology, University of Oklahoma, Norman, OK, USA.
- Oklahoma Biological Survey, University of Oklahoma, Norman, OK, USA.
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA.
| | - Rachel N Hartnett
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, USA
- Department of Science, Mount Saint Mary's University, Emmitsburg, MD, USA
| | - Thomas B Parr
- Oklahoma Biological Survey, University of Oklahoma, Norman, OK, USA
- National Park Service, Great Lakes Inventory and Monitoring Network, Ashland, WI, USA
| | - Caryn C Vaughn
- Department of Biology, University of Oklahoma, Norman, OK, USA
- Oklahoma Biological Survey, University of Oklahoma, Norman, OK, USA
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Lopez JW, Allen DC, Vaughn CC. White-tailed deer consumption of emergent macrophytes mediates aquatic-to-terrestrial nutrient flows. Ecol Evol 2022; 12:e9257. [PMID: 36110886 PMCID: PMC9465632 DOI: 10.1002/ece3.9257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/28/2022] [Accepted: 08/05/2022] [Indexed: 12/05/2022] Open
Abstract
Trophic interactions between mobile animals and their food sources often vector resource flows across ecosystem boundaries. However, the quality and quantity of such ecological subsidies may be altered by indirect interactions between seemingly unconnected taxa. We studied whether emergent macrophytes growing at the aquatic-terrestrial interface facilitate multi-step aquatic-to-terrestrial resource flows between streams and terrestrial herbivores. We also explored whether aquatic animal aggregations indirectly promote such resource flows by creating biogeochemical hotspots of nutrient cycling and availability.We tested whether white-tailed deer (Odocoileus virginianus) in eastern North America vector nutrient fluxes from streams to terrestrial ecosystems by consuming emergent macrophytes (Justicia americana) using isotope and nutrient analyses of fecal samples and motion-sensing cameras. We also tested whether mussel-generated biogeochemical hotspots might promote such fluxes by surveying the density and nutrient stoichiometry of J. americana beds growing in association with variable densities of freshwater mussels (Bivalvia: Unionoida).Fecal samples from riparian deer had 3% lower C:N and 20% lower C:P ratios than those in upland habitats. C and N isotopes suggested riparian deer ate both terrestrial and aquatic (J. americana) vegetation, whereas upland deer ate more terrestrial foods. Motion-sensing cameras showed deer eating J. americana more than twice as frequently at mussel-generated hotspots than non-mussel sites. However, mussels were not associated with variation in J. americana growth or N and P content-although N isotopes in J. americana leaves did suggest assimilation of animal-derived nutrients.Our findings suggest that white-tailed deer may conduct significant transfers of aquatic-derived nutrients into terrestrial habitats when they feed on macrophytes and defecate on land. Whether aquatic animal aggregations promote such resource flows by creating biogeochemical hotspots remains unresolved, but the nearly global distributions of the deer family (Cervidae) and of macrophytes suggest that cervid-driven aquatic-to-terrestrial nutrient flows may be widespread and ecologically important.
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Affiliation(s)
- Jonathan W. Lopez
- Department of BiologyUniversity of OklahomaNormanOklahomaUSA
- Oklahoma Biological SurveyUniversity of OklahomaNormanOklahomaUSA
- Present address:
Department of Biological SciencesUniversity of AlabamaTuscaloosaAlabamaUSA
| | - Daniel C. Allen
- Department of BiologyUniversity of OklahomaNormanOklahomaUSA
- Present address:
Department of Ecosystem Science and ManagementPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Caryn C. Vaughn
- Department of BiologyUniversity of OklahomaNormanOklahomaUSA
- Oklahoma Biological SurveyUniversity of OklahomaNormanOklahomaUSA
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Hopper GW, Buchanan JK, Sánchez González I, Kubala ME, Bucholz JR, Lodato MB, Lozier JD, Atkinson CL. Little clams with big potential: nutrient release by invasive Corbicula fluminea can exceed co-occurring freshwater mussel (Unionidae) assemblages. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02792-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hopper GW, Chen S, Sánchez González I, Bucholz JR, Lu Y, Atkinson CL. Aggregated filter‐feeders govern the flux and stoichiometry of locally available energy and nutrients in rivers. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13778] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Garrett W. Hopper
- Department of Biological Sciences University of Alabama Tuscaloosa AL USA
| | - Shuo Chen
- Department of Geological Sciences University of Alabama Tuscaloosa AL USA
| | | | - Jamie R. Bucholz
- Department of Biological Sciences University of Alabama Tuscaloosa AL USA
| | - YueHan Lu
- Department of Geological Sciences University of Alabama Tuscaloosa AL USA
| | - Carla L. Atkinson
- Department of Biological Sciences University of Alabama Tuscaloosa AL USA
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Rogers RL, Grizzard SL, Titus-McQuillan JE, Bockrath K, Patel S, Wares JP, Garner JT, Moore CC. Gene family amplification facilitates adaptation in freshwater unionid bivalve Megalonaias nervosa. Mol Ecol 2021; 30:1155-1173. [PMID: 33382161 DOI: 10.1111/mec.15786] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/01/2020] [Accepted: 12/14/2020] [Indexed: 01/05/2023]
Abstract
Freshwater unionid bivalves currently face severe anthropogenic challenges. Over 70% of species in the United States are threatened, endangered or extinct due to pollution, damming of waterways and overfishing. These species are notable for their unusual life history strategy, parasite-host co-evolution and biparental mitochondrial inheritance. Among this clade, the washboard mussel Megalonaias nervosa is one species that remains prevalent across the Southeastern United States, with robust population sizes. We have created a reference genome for M. nervosa to determine how genome content has evolved in the face of these widespread environmental challenges. We observe dynamic changes in genome content, with a burst of recent transposable element proliferation causing a 382 Mb expansion in genome content. Birth-death models suggest rapid expansions among gene families, with a mutation rate of 1.16 × 10-8 duplications per gene per generation. Cytochrome P450 gene families have experienced exceptional recent amplification beyond expectations based on genome-wide birth-death processes. These genes are associated with increased rates of amino acid changes, a signature of selection driving evolution of detox genes. Fitting evolutionary models of adaptation from standing genetic variation, we can compare adaptive potential across species and mutation types. The large population size in M. nervosa suggests a 4.7-fold advantage in the ability to adapt from standing genetic variation compared with a low diversity endemic E. hopetonensis. Estimates suggest that gene family evolution may offer an exceptional substrate of genetic variation in M. nervosa, with Psgv = 0.185 compared with Psgv = 0.067 for single nucleotide changes. Hence, we suggest that gene family evolution is a source of 'hopeful monsters' within the genome that may facilitate adaptation when selective pressures shift. These results suggest that gene family expansion is a key driver of adaptive evolution in this key species of freshwater Unionidae that is currently facing widespread environmental challenges. This work has clear implications for conservation genomics on freshwater bivalves as well as evolutionary theory. This genome represents a first step to facilitate reverse ecological genomics in Unionidae and identify the genetic underpinnings of phenotypic diversity.
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Affiliation(s)
- Rebekah L Rogers
- Department of Bioinformatics and Genomics, University of North Carolina, Charlotte, NC, USA
| | - Stephanie L Grizzard
- Department of Bioinformatics and Genomics, University of North Carolina, Charlotte, NC, USA.,Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
| | | | - Katherine Bockrath
- Department of Genetics, University of Georgia, Athens, GA, USA.,U.S. Fish and Wildlife Service, Midwest Fisheries Center Whitney Genetics Lab, Onalaska, WI, USA
| | - Sagar Patel
- Department of Bioinformatics and Genomics, University of North Carolina, Charlotte, NC, USA.,Department of Biology, Saint Louis University, St. Louis, MO, USA.,Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - John P Wares
- Department of Genetics, University of Georgia, Athens, GA, USA.,Odum School of Ecology, University of Georgia, Athens, GA, USA
| | - Jeffrey T Garner
- Division of Wildlife and Freshwater Fisheries, Alabama Department of Conservation and Natural Resources, Florence, AL, USA
| | - Cathy C Moore
- Department of Bioinformatics and Genomics, University of North Carolina, Charlotte, NC, USA
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