Wolves modulate soil nutrient heterogeneity and foliar nitrogen by configuring the distribution of ungulate carcasses

Bump, Joseph K.; Peterson, Rolf O.; Vucetich, John A.

doi:10.1890/09-0292.1

Cited by 137 publications

(168 citation statements)

References 34 publications

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“…The interannual variation that we observed (especially Table 2) is analogous to an important general lesson from the long-term observations of wolves on Isle Royale, where certain population patterns not only vary over time, but are also apparent over shorter periods of time, but not longer periods of time (e.g., Wilmers et al 2006, Bump et al 2009. If the dominant causal factors in a system vary over time, then results based on short-term dynamics would give clear, but misleading impressions of what's happening; and results from longer-term studies would be characterized by less obvious patterns (Vucetich et al 2010, Nelson et al 2011.…”

Section: Discussionsupporting

confidence: 76%

Long‐ and short‐term temporal variability in habitat selection of a top predator

et al. 2015

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Abstract. Considerable theory explains the importance of understanding temporal variation in ecological processes. Nevertheless, long-term variability in habitat selection is rarely assessed or even acknowledged. We explored temporal variability in the habitat selection of a top-predator, the wolf (Canis lupus), at two time scales: interannual and seasonal variability. To do this, we developed resource utilization functions to relate wolf habitat selection to environmental variables in different years and seasons. We used radiotelemetry data collected from a wolf population in Yellowstone National Park during a 10-year period (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) and added a Year variable in the models to account for interannual variation in the studied processes. We also used a three-year data set (nested within the 10-year data set) to incorporate additional variables in the models and test for differences in short-and long-term patterns of habitat selection. Wolves exhibited seasonal variation in habitat selection with respect to distance from roads, elevation, openness, and habitat type. Habitat selection was considerably more complicated during the winter compared to summer, when wolves only selected habitat based on distance from roads. We detected clear patterns of habitat selection in the three-year data set that could not be detected in the 10-year data set, despite the longer data set had more statistical power for pattern detection. This observation is likely the result of the longer data set being comprised of several shorter-term and countervailing patterns. This explanation is also consistent with having detected significant year effects in the 10-year data set. Insomuch as habitat selection is important to conservation and management, this research is significant for demonstrating the different impressions that can be given by short-term and long-term studies. It may be common for short-term data sets to suggest patterns of habitat selection that do not prevail over longer periods of time.

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Section: Discussionsupporting

confidence: 76%

Long‐ and short‐term temporal variability in habitat selection of a top predator

et al. 2015

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“…The amount of soil ingestion from inadvertent versus intentional sources would alter pathogen exposure, depending on the probability that grazing or lick areas intersect with pathogen aggregations. Since carcass sites can be nutrient hot spots and alter the community composition or nutritional quality of grasses (Towne 2000, Bump et al 2009), we speculate that these areas could be sources of attraction to herbivores. If increased soil exposure puts animals at a greater risk of ingesting a soil-borne pathogen, then herbivores should be at the highest risk during the vegetation growing season, when grasses are most palatable and soil moisture and low grass height supports the plucking of whole plants (and the associated soil attached to roots) while grazing.…”

Section: Seasonality Of Soil Ingestionmentioning

confidence: 99%

Soil ingestion, nutrition and the seasonality of anthrax in herbivores of Etosha National Park

et al. 2013

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Abstract. Anthrax, caused by the bacterium Bacillus anthracis, is a seasonally occurring infectious disease affecting primarily herbivorous wildlife and livestock. The seasonality of anthrax outbreaks varies among locations, making it difficult to develop a single consistent ecological description of this disease. Over 44 years of mortality surveillance, most anthrax cases in Etosha National Park, Namibia are observed in the wet season, although elephants have an anthrax mortality peak in the dry season. Focusing on three host species (plains zebra, Equus quagga; African elephant, Loxodonta africana; and springbok, Antidorcas marsupialis) occupying the endemic anthrax area of Etosha National Park, Namibia, we tested two commonly posited causes of anthrax seasonality in herbivores: increased pathogen exposure due to greater soil contact, and increased host susceptibility due to seasonal nutritional stress. These hypotheses were assessed using fecal sampling and measurement of the percentage of fecal silicates as an index of soil ingestion and fecal nitrogen, phosphorus and crude fiber as nutritional indices. Nutritional quality for all three species was higher in wet than dry seasons. Comparing among wet seasons, nutritional indices showed either a decline in nutrition with increasing rainfall or no significant pattern. All three species had greater soil ingestion in the wet season than the dry season. Higher soil contact during the anthrax peak suggests that anthrax seasonality may in part be due to heightened exposure to B. anthracis in wet seasons, for zebra and springbok. Elephant anthrax deaths do not correspond with the season of increased soil ingestion or grazing, suggesting that other behavioral mechanisms may overshadow foraging-based risk factors for this species. Nutritional stress is unlikely the primary causative factor in wet season anthrax systems, although nutritional stress sufficient to reduce resistance is difficult to assess non-invasively in wild herbivores. In contrast, increased soil ingestion may be an important predisposing factor for wet season anthrax outbreaks. Ultimately, the amount of soil ingested and its importance in the transmission of soil-borne pathogens will vary based on foraging behaviors, intake rates, grassland structure and on the likelihood that foraging areas intersect with pathogen aggregations in the environment.

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“…Herbivores are assumed to recycle N and C through baseline egestion, excretion and natural mortality (Vanni 2002; Bump et al. 2009; Schmitz et al. 2010).…”

Section: The Theoretical Frameworkmentioning

confidence: 99%

Predator‐driven elemental cycling: the impact of predation and risk effects on ecosystem stoichiometry

Leroux

Schmitz

2015

Ecology and Evolution

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Empirical evidence is beginning to show that predators can be important drivers of elemental cycling within ecosystems by propagating indirect effects that determine the distribution of elements among trophic levels as well as determine the chemical content of organic matter that becomes decomposed by microbes. These indirect effects can be propagated by predator consumptive effects on prey, nonconsumptive (risk) effects, or a combination of both. Currently, there is insufficient theory to predict how such predator effects should propagate throughout ecosystems. We present here a theoretical framework for exploring predator effects on ecosystem elemental cycling to encourage further empirical quantification. We use a classic ecosystem trophic compartment model as a basis for our analyses but infuse principles from ecological stoichiometry into the analyses of elemental cycling. Using a combined analytical‐numerical approach, we compare how predators affect cycling through consumptive effects in which they control the flux of nutrients up trophic chains; through risk effects in which they change the homeostatic elemental balance of herbivore prey which accordingly changes the element ratio herbivores select from plants; and through a combination of both effects. Our analysis reveals that predators can have quantitatively important effects on elemental cycling, relative to a model formalism that excludes predator effects. Furthermore, the feedbacks due to predator nonconsumptive effects often have the quantitatively strongest impact on whole ecosystem elemental stocks, production and efficiency rates, and recycling fluxes by changing the stoichiometric balance of all trophic levels. Our modeling framework predictably shows how bottom‐up control by microbes and top‐down control by predators on ecosystems become interdependent when top predator effects permeate ecosystems.

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Wolves modulate soil nutrient heterogeneity and foliar nitrogen by configuring the distribution of ungulate carcasses

Cited by 137 publications

References 34 publications

Long‐ and short‐term temporal variability in habitat selection of a top predator

Long‐ and short‐term temporal variability in habitat selection of a top predator

Soil ingestion, nutrition and the seasonality of anthrax in herbivores of Etosha National Park

Predator‐driven elemental cycling: the impact of predation and risk effects on ecosystem stoichiometry

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