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Full-Text Articles in Animal Sciences

Absence Of Predation Eliminates Coexistence: Experience From The Fish-Zooplankton Interface, Z. M. Gilwicz, Wayne A. Wurtsbaugh, E. Szymansk Jan 2010

Absence Of Predation Eliminates Coexistence: Experience From The Fish-Zooplankton Interface, Z. M. Gilwicz, Wayne A. Wurtsbaugh, E. Szymansk

Watershed Sciences Faculty Publications

Examples from fishless aquatic habitats show that competition among zooplankton for resources instigates rapid exclusion of competitively inferior species in the absence of fish predation, and leads to resource monopolization by the superior competitor. This may be a single species or a few clones with large body size: a cladoceran such as Daphnia pulicaria, or a branchiopod such as Artemia franciscana, each building its population to a density far higher than those found in habitats with fish. The example of zooplankton from two different fish-free habitats demonstrates the overpowering force of fish predation by highlighting the consequences of its absence. …


Proportion Of Calves And Adult Muskoxen, Ovibos Moschatus Killed By Gray Wolves, Canis Lupus, In July On Ellesmere Island, L. David Mech Jan 2010

Proportion Of Calves And Adult Muskoxen, Ovibos Moschatus Killed By Gray Wolves, Canis Lupus, In July On Ellesmere Island, L. David Mech

USGS Northern Prairie Wildlife Research Center

Generally Gray Wolves (Canis lupus L., 1758) tend to focus predation on young-of-the-year ungulates during summer, and I hypothesized that wolves preying on Muskoxen (Ovibos moschatus Zimmerman, 1780) in summer would follow that trend. Over 23 July periods observing wolves on Ellesmere Island, Nunavut, Canada, I found that packs of 2-12 adult wolves killed seven calves, one yearling, and five adult muskoxen at distances of 2.9 to 32 km from their current dens and pups. Given a possible bias against finding calves because of their fewer remains, these results do not necessarily refute the hypothesis, but they do …


Antipredatory Defense Of Neonatal Pronghorn (Antilocapra Americana) By Yearling Male Pronghorn In Southwestern South Dakota, Christopher N. Jacques, Jonathan A. Jenks Jan 2010

Antipredatory Defense Of Neonatal Pronghorn (Antilocapra Americana) By Yearling Male Pronghorn In Southwestern South Dakota, Christopher N. Jacques, Jonathan A. Jenks

Natural Resource Management Faculty Publications

Antipredatory defense of pronghorn (Antilocapra americana) neonates (≤1 month old) by adult females (>18 months old) is well documented throughout the geographic range of this species. However, reports of male pronghorn defending neonates against predators are limited to a single study in northwestern Wyoming where occurrences were documented of adult males assisting female pronghorn in defending neonates against coyotes (Canis latrans). To our knowledge, defense of neonatal pronghorn by yearling males (12–18 months old) has not been reported previously for this species. We report occurrences of antipredatory defense of neonatal pronghorn by yearling males in southwestern South Dakota