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Appalachian stream fish diversity: The more the merrier!

Brook Trout (adult and young of year) and Blacknose Dace (stripped fish) caught during steam sampling. USDA Forest Service photo by Colin Krause.

The relationship between diversity and productivity in ecosystems has fascinated scientists for decades but is not well understood in freshwater fish communities. USDA Forest Service scientist Andrew Dolloff co-authored a study that found a positive relationship between fish production and fish biodiversity.

Fish production is an expansive metric. It represents the number of individuals, their weight, and their annual growth. Studies measuring fish production are exceedingly rare, in part because of the extensive effort required to estimate production for every species in a fish community.

Dolloff, with colleagues from Virginia Polytechnic Institute, Northern Research Station, and University of California, examined the relationship between fish production and fish species diversity in 25 Appalachian freshwater streams with different thermal signatures, and histories of species introductions, and locations from North Carolina to Vermont.

The researchers found that more species meant greater production. With each additional species, fish production increased by 0.06 grams per square meter per year, after accounting for other aspects of habitat also are associated with production.

Freshwater fish are vulnerable to climate change and other human impacts. As the climate continues to warm, now is the time to increase understanding of freshwater ecosystems to inform conservation research and management.

Read the article in Diversity and Distributions. For more information, email Andrew Dolloff at

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