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Browsing by Author "Myers, Bonnie J. E."

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    Diversity-production relationships of fish communities in freshwater stream ecosystems
    Myers, Bonnie J. E.; Dolloff, C. Andrew; Webster, Jackson R.; Nislow, Keith H.; Rypel, Andrew L. (2021-09)
    Aim Ecological relationships between species richness and biomass production are increasingly thought to be pervasive across the globe. Yet, diversity-production relationships have not been explored extensively for freshwater fish communities even though fisheries production provides key services to humans. Our aim was to evaluate the diversity-production relationship of fish communities inhabiting freshwater streams across the Appalachian Mountain range and examine how diversity-production relationships varied across streams possessing different thermal signatures. Location Our study area included 25 freshwater stream ecosystems spanning from Vermont to North Carolina in the United States. Twenty sites were located in Maryland south to Tennessee and North Carolina, while five additional higher latitude sites were sampled in Massachusetts and Vermont. Methods We sampled the 25 study streams from June to September 2012 and collected fish population information to calculate biomass, species richness, the Shannon diversity index and annual production for each fish community. Linear mixed effects models were used to analyse the relationship between diversity indices and total community production. We also compared diversity and production relationships across other taxa. Results Across all streams, community fish production, biomass and P/B ratios ranged from 0.15-6.79 g m(-)(2) y(-)(1), 0.61-0.73 g m(-)(2) and 0.21-1.07 y(-1), respectively. Species richness had a significant positive effect (p = .012) on community fish production, while accounting for the thermal signature of the streams as a random effect and other habitat covariates. The Shannon diversity index did not have a significant effect (p = .101) on community production. Main conclusions The diversity-production relationship observed for stream fish communities was similar to other studies but demonstrated one of the highest slopes. Our results demonstrate that effects of biodiversity resonate to influence the production of fishes; thus, management of fisheries is more closely coupled to biodiversity than previously thought.
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    Variations in Community Fish Production and Diversity Across the Appalachians: Implications for Climate Change
    Myers, Bonnie J. E. (Virginia Tech, 2014-03-04)
    Climate change is considered a major threat to freshwater ecosystems through altering biodiversity, structure, and function. Having a thorough understanding of how diverse ecosystems respond to temperature change is vital to ecosystem management and conservation. During summer 2012, I quantified fish biomass, somatic growth, secondary production, and habitat data for fish communities in 25 Appalachian streams from Vermont to North Carolina. Multiple statistical tests were conducted to determine the relationship between community fish production and air and water temperature, species thermal guild production and air and water temperature, and the relationship between community fish production and diversity. Community fish production estimates ranged from 0.15 to 6.79 g m-2 yr-1 and community P/B ratios ranged from 0.21 to 1.07. No significant differences existed between mean community production estimates at the cold-water, cool-water, warm-water, and extreme northern sites (P=0.19), but P/B ratios in the extreme northern streams were statistically higher than mean community P/B in cold- and cool-water streams in the southern Appalachians (P=0.002). Water temperatures had a positive effect on community fish production (P=0.01) while air temperatures did not (P=0.10). Both air and water temperatures were significant in predicting whether community production would be dominated by cold-water or cool-water fish (P=0.001, P<0.0001, respectively). Community fish production was significantly, positively related to species richness (R2=0.38, P=0.001) and was one of the highest correlates of community production (R2=0.52). As climate change alters freshwater ecosystems, fish communities may transform by means of shifting fish abundance, biomass, and production among species ultimately affecting ecosystem structure, function, and biodiversity.