Top–down control by great blue herons regulates seagrass-associated epifauna
A 2015 paper in Oikos Journal examines the impacts of great blue heron predation on species diversity in eelgrass meadows in British Columbia.
Using a combination of behavioral observations and experimental manipulations, scientists from British Columbia recently showed that great blue heron predation reduces benthic (seafloor fish abundance), but increases diversity of invertebrates. Where herons were excluded from foraging, benthic fish populations increased, which increased fish predation on invertebrates. Specifically, in areas where herons where excluded, isopods and Heptacarpus shrimp numbers were reduced. Epiphyte abundance was actually reduced where herons were present compared to heron excluded sites, which is likely related to heron predation ultimately altering the community of grazing invertebrates. This study shows that, as predators of small fishes, great blue herons can influence the diversity of eelgrass meadows where large numbers of herons congregate to feed during summer months.
— Joe Gaydos, Encyclopedia of Puget Sound topic editor for birds and mammals
Citation
Huang, A.C. et al. (2015) Top– down control by great blue herons Ardea herodias regulates seagrass-associated epifauna. Oikos Journal. doi: 10.1111/oik.01988.
