Spatial ecology of predator-prey interactions: corridors and patch shape influence seed predation.
- USDA Forest Service, Savannah River
J.L. Orrock, B.J. Danielson, M.J. Burns, and D.J. Levey. 2003. Spatial ecology of predator-prey interactions: corridors and patch shape influence seed predation. Ecology, 84(10):2589-2599. Abstract: Corridors that connect patches of disjunct habitat may be promising tools for mediating the negative impacts of habitat fragmentation, but little is known about how corridors affect ecological interactions. In eight 12-ha experimental landscapes, we examined how corridors affect the impact of invertebrate, rodent, and avian seed predators on pokeweed, Phytolacca americana. Over 13 months in 2000 and 2001, we quantified the effects of patch shape, connectivity, and predator type on the number of seeds germinating in the field (germinants), seed removal, and the viability of remaining seeds. Corridors did not affect the number of P. americana germinants in experimental exclosures or the viability of seeds remaining in exclosures. However, corridors affected the removal of seeds in a predator-specific manner: invertebrates removed more seeds in unconnected patches, whereas rodents removed more seeds in connected patches. Seed removal by birds was similar in connected and unconnected patches. Total seed removal by all seed predators was not affected by corridors, because invertebrates removed more seeds where rodents removed fewer seeds, and vice versa. Overall, seed predation signi®cantly reduced the number and viability of remaining seeds, and reduced the number of germinants in 2000 but not in 2001. The abundance of naturally occurring P. americana plants in our experimental patches in 2000 decreased with increasing seed removal from exclosures but was not related to viability or germinants in 2000, suggesting that seed removal may shape the distribution and abundance of this species. Complementary patterns of seed removal by rodents and invertebrates suggest that corridors alter the effects of these predator taxa by changing the relative amounts of edge and core (nonedge) habitats in a patch. Because invertebrates and rodents do not completely overlap in the seeds they consume, corridors may change predation pressure on seeds that are primarily consumed by one predator type, with potential consequences for the composition of plant and seed predator communities.
- Research Organization:
- USDA Forest Service, Savannah River, New Ellenton, SC
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM)
- DOE Contract Number:
- AI09-00SR22188
- OSTI ID:
- 835192
- Report Number(s):
- na; 03-24-P
- Journal Information:
- Ecology, Journal Name: Ecology Journal Issue: 10 Vol. 84; ISSN 2589-2599
- Country of Publication:
- United States
- Language:
- English
Similar Records
Corridors cause differential seed predation.
Patch shape, connectivity, and foraging by oldfield mice (Peromyscus polionotus).
Related Subjects
ABUNDANCE
BIRDS
COMMUNITIES
Corridors
DISTRIBUTION
ECOLOGY
FRAGMENTATION
HABITAT
INVERTEBRATES
PREDATOR-PREY INTERACTIONS
Phytolacca Americana
REMOVAL
RODENTS
SEEDS
SHAPE
Savannah River Site
South Carolina (USA)
VIABILITY
patch shape
preditor-prey interactions
seed predation.