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Abstract This study aimed to identify the importance of ecological factors to distribution patterns of the invasive Clam (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 invasiveCorbiculawithin mussel beds. We found thatCorbiculawere 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,Corbiculadensities 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 influencedCorbiculapopulations or mussel communities. The strong overlapping distribution ofCorbiculaand mussels support the hypothesis thatCorbiculaare not necessarily limited by habitat factors and may be passengers of change in rivers where mussels have declined due to habitat degradation. WhetherCorbiculais 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 betweenCorbiculaand native mussels.
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Drivers of ecosystem vulnerability to Corbicula invasions in southeastern North America
Abstract Invasive species introduction is one of the major ongoing ecological global crises. Identifying factors responsible for the success of invasive species is key for the implementation of effective management actions. The invasive filter-feeding bivalve,Corbicula, is of particular interest because it has become ubiquitous in many river basins across North America and elsewhere. Here we sampled bivalve assemblages, environmental indicators, and land cover parameters in the Ouachita highlands in southeastern Oklahoma and southwestern Arkansas, and in the Gulf Coastal Plain of Alabama to test three working models (using structural equation modeling, SEM) based on a priori scientific knowledge regardingCorbiculainvasions. Our models tested three competing hypotheses: (1) Native mussel declines are related to land use changes at the watershed level and subsequentCorbiculacolonization is a result of an empty niche; (2)Corbiculaabundance is one of the factors responsible for native mussel declines and has an interactive effect with land use change at the watershed level; (3) Native mussel declines andCorbiculasuccess are both related to land use changes at the watershed level. We found no evidence for the first two hypotheses. However, we found that environmental indicators and land cover parameters at the watershed scale were robust predictors ofCorbiculaabundance. In particular, agricultural land cover was positively related withCorbiculadensity. These results suggest that further improvement of conventional agricultural practices including the optimization of fertilizer delivery systems may represent an opportunity to manage this species by limiting nutrient inputs to stream ecosystems. Preservation of extensive floodplain habitats may help buffer these inputs by providing key ecosystem services including sediment and nutrient retention.
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- Award ID(s):
- 1831512
- PAR ID:
- 10366909
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Biological Invasions
- Volume:
- 24
- Issue:
- 6
- ISSN:
- 1387-3547
- Page Range / eLocation ID:
- p. 1677-1688
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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