Eastern Red Cedar (Juniperus virginiana) is native to the eastern United States. During the past 50 years, Eastern Red Cedar has been encroaching into grassland and prairie ecosystems of the Western US. Eastern Red Cedar outcompetes native species, forming dense monocultures and lowering the biodiversity of these areas. The process of invasion/encroachment occurs primarily through seed dispersal by birds and mammals. During winter, the outer covering of the seed provides nutrients when other food is scarce, and foraging increases due to the lack of other resources. In avian species, seed dispersal depends on the distance traveled, which varies based on whether bird species are resident, nomadic, or migratory. For example, mammals and resident birds typically disperse seeds short distances while nomadic or migratory birds tend to move seeds longer distances. These trees also provide nesting opportunities for birds in these ecosystems, which are usually lacking in tree cover. In this project, we focus on seed dispersal of the Eastern Red Cedar using wildlife cameras to monitor bird and mammal foraging behavior in two grassland habitats with low human interference. Cameras were placed at the crown and base of five trees at each site to observe all foraging.
Results/Conclusions
We focus on the seasonality of foraging behavior by birds and mammals and how it influences seed dispersal and encroachment of Eastern Red Cedar. Mammal species observed include white-tailed deer, Virginia opossum, Eastern cottontail rabbit, squirrels, and various vole/mice species. Birds using Eastern Red Cedar include American robins, cedar waxwings, Eastern bluebirds, and blue jays. Mammalian foraging was very consistent over time, while birds were more infrequent/episodic in their use of Eastern Red Cedar. 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 are more episodic in their feeding, with greater potential for longer-distance dispersal of Eastern Red Cedar.