Biology subjects

Keogh, S. M.

Publications and source records attributed to Keogh, S. M..

2 recordsLinked to original sources

bioRxiv2023

Conspicuous shell shape plasticity across lake-stream habitats in a freshwater mussel (Pyganodon grandis)

2.Hydrodynamic forces and their absence appears to exert differential selection pressure between lake and stream populations, creating a tight fit between organismal phenotypes and their environments. Ecophenotypic variants may be the result from isolated genetic evolution or phenotypic plasticity, where a widespread genotype can produce multiple phenotypes dependent on the environment. Freshwater mussels possess a wide degree of morphological variation that frequently covaries with the environment, making them a good system to understand the mechanisms of ecophenotypic variation across hydrological conditions. We designed a two-year experiment where individuals from the same Pyganodon grandis maternal brood (half-full siblings) were reared at a controlled site and four natural sites involving one lake and three streams. At the end of the experiment, shell shape was quantified for recaptured (N=70), wild (N=206), and zoo-reared (N=305) mussels. Analysis of covariance found significant differences in shell shape between rearing sites, particularly between stream and lake habitats, but no shape differences were detected across the three stream sites. At two of the four sites, shell shape of recaptured individuals matched the morphology of wild populations. Genomic sequencing and parentage analysis identified 27 different fathers among recaptured individuals. Yet, no genetic differences were present between stream and lake habitats and there was no effect of parentage on shell shape. Taken together, phenotypic plasticity, over genetic differentiation, is identified as the primary mechanism of shell shape ecophenotypy. Plasticity may be a key adaptation for freshwater mussels and possibly provide a buffer against their imperilment in degraded habitats. 1. Summary statementStreamlined and obese freshwater mussel shell shapes in stream-lake environments are developed from the same maternal brood and may reflect adaptations to the presence and absence of streamflow.

ecology↗

bioRxiv2022

Synthesis of natural history collections data reveals patterns of US freshwater mussel diversity and decline

Natural history collections are uniquely positioned to chronicle biodiversity changes across time and space and are a fundamental data source in taxon-based research and conservation. With over 90 species listed under the Endangered Species Act, freshwater mussels are one of the most imperiled animal assemblages in the United States and are the focus of considerable conservation efforts (e.g., species status assessments, listing decisions, and recovery plans). Unfortunately, natural history collections data is often underleveraged in such efforts, in part, because much of the data are decentralized and nonstandard, and thus, difficult to access and analyze. Our objective herein is to synthesize, standardize, and enrich digitized US freshwater mussel collections data to better suit the needs of conservation stakeholders. We aggregated specimen records from 45 US natural history collections and enriched these records by programmatically standardizing taxonomic information, flagging potentially problematic records, and joining records with freshwater-specific spatial frameworks (e.g., hydrological units and stream segments) and their associated metadata (e.g., area, stream order, discharge, velocity). The assembled dataset includes 410,665 records, 302 species, and 1,494 hydrological units (8 digit-level). Using these enriched records, we estimated ecological attributes for over 280 freshwater mussel species including aspects of range size (i.e., area of occupancy and change in area of occupancy) and habitat preferences (i.e., stream order size, discharge, slope, and velocity). Listed species had significantly fewer occurrences (p<0.001) and smaller area of occupancy (p<0.001) in comparison to non-listed listed species. Listed species also tended to have a higher stream order preference (p<0.001) and discharge preference than non-listed species (p<0.001). These important ecological attributes have not been incorporated into freshwater mussel conservation efforts in a quantitative way and our novel estimates can be used to make more data-driven ecological and conservation inferences.

ecology↗