Abstract |
During the past 50 years, Eastern red cedar (Juniperus virginiana), native to the Eastern United States, has been encroaching into grassland/prairie ecosystems in the US. Eastern red cedar (ERC) outcompetes native species, forming dense monocultures and lowering biodiversity. The process of encroachment occurs through seed dispersal by birds and mammals. The outer covering of seeds provides nutrients when other food is scarce, and foraging increases due to the lack of other resources in winter. In avian species, seed dispersal depends on distance traveled based on whether birds are resident, nomadic, or migratory. Mammals and resident birds typically disperse seeds short distances while nomadic or migratory birds tend to move seeds longer distances. We focus on seed dispersal of the ERC using wildlife cameras to monitor bird and mammal foraging behavior in two grassland habitats. Cameras were placed at the crown and base of five trees at each site to observe foraging. We focus on the seasonality of foraging behavior by birds and mammals and how it influences seed dispersal and encroachment of ERC. Mammal species observed include white-tailed deer, Virginia opossum, Eastern cottontail rabbit, and rodents. Birds using ERC include robins, cedar waxwings, bluebirds, and blue jays. Mammalian foraging was very consistent over time, while birds were more episodic in their use of ERC. Overall, mammals and resident bird species were most consistently observed and likely to be important for short-distance seed dispersal, while nomadic and migratory birds have a greater potential for longer-distance dispersal of Eastern red cedar.
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