This study aimed to identify the importance of ecological factors to distribution patterns of the invasive Clam (
- Award ID(s):
- 1757348
- NSF-PAR ID:
- 10423935
- Date Published:
- Journal Name:
- Estuaries and Coasts
- ISSN:
- 1559-2723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Corbicula fluminea ) relative to native mussels (family: Unionidae) across seven rivers within the Mobile and Tennessee basins, Southeast United States. We quantitatively surveyed dense, diverse native mussel aggregations across 20 river reaches and estimated mussel density, biomass, and species richness along with density of invasiveC .fluminea (hereafterCorbicula ). We measured substrate particle size, velocity, and depth in quadrats where animals were collected. Additionally, we characterized reach scale environmental parameters including seston quantity and quality (% Carbon, % Nitrogen, % Phosphorous), water chemistry (ammonium [], soluble reactive phosphorous [SRP]), and watershed area and land cover. Using model selection, logistic regression, and multivariate analysis, we characterized habitat features and their association to invasiveCorbicula within mussel beds. We found thatCorbicula were more likely to occur and more abundant in quadrats with greater mussel biomass, larger substrate size, faster water velocity, and shallower water depth. At the reach scale,Corbicula densities increased where particle sizes were larger. Mussel richness, density, and biomass increased with watershed area. Water column increased at reaches with more urban land cover. No land cover variables influencedCorbicula populations or mussel communities. The strong overlapping distribution ofCorbicula and mussels support the hypothesis thatCorbicula are not necessarily limited by habitat factors and may be passengers of change in rivers where mussels have declined due to habitat degradation. WhetherCorbicula is facilitated by mussels or negatively interacts with mussels in these systems remains to be seen. Focused experiments that manipulate patch scale variables would improve our understanding of the role of species interactions (e.g., competition, predation, facilitation) or physical habitat factors in influencing spatial overlap betweenCorbicula and native mussels. -
The use of environmental DNA (eDNA) to assess aquatic biodiversity is a growing field with great potential for monitoring and managing threatened species, like freshwater mussel (Unionidae) populations. Freshwater mussels are globally imperiled and serve essential roles in aquatic systems as a food source and as a natural water filter making their management essential for ecosystem health. Unfortunately, mussel populations are often understudied, and challenges exist to accurately and efficiently describe the full suite of species present. Multispecies eDNA approaches may also be more challenging where freshwater mussel populations are most diverse due to ongoing and significant taxonomic restructuring that has been further complicated by molecular phylogenies using mitochondrial genes. For this study, we developed a microfluidic metabarcoding array that targets a wide range of species, from invertebrates to fishes, with an emphasis on detecting unionid mussels known to be present in the Sipsey River, Alabama. We compared mussel species diversity across six sites with well-studied mussel assemblages using eDNA surveys and traditional quadrat surveys in 2016. We examined how factors such as mussel population density, biomass and location in the river substrate impacted our ability to detect certain species; and investigated unexpected eDNA detections through phylogenetic analysis. Our eDNA results for fish and mussel species were broadly consistent with the data from traditional electrofishing and quadrat-based field surveys, although both community eDNA and conventional sampling detected species unique to that method. Our phylogenetic analysis agreed with other studies that treat Pleurobema decisum and P. chattanoogaense as synonymous species; however, they are still listed as unique species in molecular databases which complicates their identity in a metabarcoding assay. We also found that Fusconaia flava and F. cerina are indistinguishable from one another using a portion of the NADH dehydrogenase Subunit 1 (ND1) marker, which may warrant further investigation into whether or not they are synonymous. Our results show that many factors impacted our ability to detect and correctly identify Unionidae mussel species. Here we describe the obstacles we faced, including the murky phylogeny of Unionidae mussels and turbid river conditions, and our development of a potentially impactful freshwater mussel monitoring eDNA assay.more » « less
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Abstract Freshwater mussels are important for nutrient cycling and ecosystem health as they filter feed on their surrounding water. This filter feeding makes these bivalves especially sensitive to conditions in their environment. Gut microbial communities (microbiomes) have been recognised as important to both host organism and ecosystem health; however, how freshwater mussel microbiomes are organised and influenced is unclear.
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null (Ed.)Mytilid mussels form abundant, species-rich reefs on rocky substrates, but the role of this key habitat in carbon (C) cycling remains poorly understood. We performed a seasonal study on a 5 m deep photic Mytilus trossulus reef in the Central Baltic Sea to investigate pathways and rates of organic C flow. Reef gross primary production (GPP) and respiration ( R ) were estimated seasonally using underwater O 2 eddy covariance on hourly and daily timescales. Photogrammetry and biotic sampling were used to quantify reef rugosity and mussel coverage, and to derive mussel filtration and biodeposition. Mussels were highly abundant, reaching ~50000 ind. m -2 , and the reef structure increased the seabed surface area by 44%. GPP hourly was up to 20 mmol O 2 m -2 h -1 and GPP daily was up to 107 mmol O 2 m -2 d -1 , comparable to a nearby seagrass canopy. Hourly eddy fluxes responded linearly to light intensity and flow velocity, with higher velocities enhancing reef O 2 uptake at night. Reef R daily exceeded GPP daily on 12 of 13 measurement days, and R annual (29 mol O 2 m -2 yr -1 ) was 3-fold larger than GPP annual . The reef sustained a productive community of microbes and fauna whose activities accounted for ~50% of R annual . Horizontal water advection promoted food supply to the reef and likely facilitated substantial lateral C export of mussel biodeposits. Our analyses suggest that a reduction in mussel reef extent due to ongoing environmental change will have major implications for the transport and transformation of C and nutrients within the coastal Baltic Sea.more » « less
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ABSTRACT Intertidal mussels (Mytilus spp.) and their benthic invertebrate predators were monitored annually for 25 years at 10 sites within Lough Hyne Marine Reserve in southwest Ireland. Mussel abundance was relatively low in the early 1990s but increased substantially after the cold winter of 1995/1996. High mussel abundance was maintained until 2014 after which there was an abrupt decline leading to low levels in 2015–2019, when populations were dominated by older size-classes. Recruitment on benthic rock surfaces in 2018 and 2019 was low in contrast to that on an isolated mooring rope in deep water, suggesting mortality of recruits (e.g. from predation or benthic hypoxia). The generalist predatory starfish, Marthasterias glacialis, increased substantially during the study, with population peaks in 2005 and 2009 that mirrored the peaks of mussel populations. Predatory dogwhelks were not abundant at the monitoring sites and were never seen associated with mussels. Predators or other physical factors may have reduced recruitment, but the decline of the mussel population probably reflected increasing age and removal by wave action combined with consistently sparse recruitment.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s12237-023-01175-0
