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The reintroduction of gray wolves to Yellowstone National Park (YNP) provides a natural experiment regarding the effects of top predators on scavenger species. Fieldwork on the Northern Range of Yellowstone indicates that wolves facilitate carrion acquisition by scavengers, but it is unclear whether this represents a transient or permanent effect of wolf reintroduction. Here we present a wolf-elk model with human elk harvest and use it to investigate the long-term consequences of predator?prey dynamics and hunting on resource flow to scavengers. Our model shows that while wolves reduce the total amount of carrion, they stabilize carrion abundance by reducing temporal variation in the quantity of carrion and extending...
A central challenge in applied ecology is understanding the effect of anthropogenic fatalities on wildlife populations and predicting which populations may be particularly vulnerable and in greatest need of management attention. We used 3 approaches to investigate potential effects of fatalities from collisions with wind turbines on 14 raptor species for both current (106 GW) and anticipated future (241 GW) levels of installed wind energy capacity in the United States. Our goals were to identify species at relatively high vs low risk of experiencing population declines from turbine collisions and to also compare results generated from these approaches. Two of the approaches used a calculated turbine-caused mortality...
1 Resource pulses generally result in a burst of biological activity at multiple scales. For plants, the increased activity is generally considered positive due to an overall up-regulation of physiological activity during the pulse. Longer-term effects remain an understudied aspect of resource pulses. 2 We monitored the short- and long-term effects of nitrogen (N) pulse to the long-lived desert perennial, Cryptantha flava. One group of plants were treated with a one-time application of N in the spring of 1999, a second group received two N pulses (one in the spring of 1999 and one in the spring of 2000), and a third group received ambient N (controls). 3 In the short-term, N-pulse treated plants rapidly increased...
Like many other species, cutthroat trout (Oncorhynchus clarki) have declined substantially relative to historic conditions, and many existing populations are isolated. To inform conservation and restoration efforts for stream-resident cutthroat trout, I built a stage-structured stochastic simulation model to explore the dynamics of populations in isolation or connected by immigration. Relatively small increases in carrying capacity substantially reduced extinction risk in small, isolated populations. In the sensitivity matrix, the two most important elements affecting population growth rate were the survival of subadults that became reproductively mature the next year and the survival of young-of-the-year fish....


    map background search result map search result map Demographic and potential biological removal models identify raptor species sensitive to current and future wind energy Demographic and potential biological removal models identify raptor species sensitive to current and future wind energy