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Full-Text Articles in Life Sciences
Bison Alter The Northern Yellowstone Ecosystem By Breaking Aspen Saplings, Luke E. Painter, Robert L. Beschta, William J. Ripple
Bison Alter The Northern Yellowstone Ecosystem By Breaking Aspen Saplings, Luke E. Painter, Robert L. Beschta, William J. Ripple
Aspen Bibliography
The American bison (Bison bison) is a species that strongly interacts with its environment, yet the effects of this large herbivore on quaking aspen (Populus tremuloides) have received little study. We documented bison breaking the stems of aspen saplings (young aspen > 2 m tall and ≤ 5 cm in diameter at breast height) and examined the extent of this effect in northern Yellowstone National Park (YNP). Low densities of Rocky Mountain elk (Cervus canadensis) after about 2004 created conditions conducive for new aspen recruitment in YNP's northern ungulate winter range (northern range). We sampled …
Revisiting Trophic Cascades And Aspen Recovery In Northern Yellowstone, Robert L. Beschta, Luke E. Painter, William J. Ripple
Revisiting Trophic Cascades And Aspen Recovery In Northern Yellowstone, Robert L. Beschta, Luke E. Painter, William J. Ripple
Aspen Bibliography
We revisit the nature and extent of trophic cascades and quaking aspen (Populus tremuloides) recovery in the northern range of Yellowstone National Park (YNP), where studies have reported on Rocky Mountain elk (Cervus canadensis) browsing and young aspen heights following the St. John, 1995-96 reintroduction of gray wolves (Canis lupus). A recent study by Brice et al. (2021) expressed concerns about methodologies employed in earlier aspen studies and that results from those studies exaggerated the extent to which a trophic cascade has benefitted aspen, concerns such as: (a) the selection of aspen stands, (b) …
Sampling Bias Exaggerates A Textbook Example Of A Trophic Cascade, Elaine M. Brice, Eric J. Larsen, Daniel R. Macnulty
Sampling Bias Exaggerates A Textbook Example Of A Trophic Cascade, Elaine M. Brice, Eric J. Larsen, Daniel R. Macnulty
Aspen Bibliography
Understanding trophic cascades in terrestrial wildlife communities is a major challenge because these systems are difficult to sample properly. We show how a tradition of non-random sampling has confounded this understanding in a textbook system (Yellowstone National Park) where carnivore [Canis lupus (wolf)] recovery is associated with a trophic cascade involving changes in herbivore [Cervus canadensis (elk)] behaviour and density that promote plant regeneration. Long-term data indicate a practice of sampling only the tallest young plants overestimated regeneration of overstory aspen (Populus tremuloides) by a factor of 4–7 compared to random sampling because it favoured plants taller than the preferred …
Aspen Recruitment In The Yellowstone Region Linked To Reduced Herbivory After Large Carnivore Restoration, Luke E. Painter, Robert L. Beschta, Eric J. Larsen, William J. Ripple
Aspen Recruitment In The Yellowstone Region Linked To Reduced Herbivory After Large Carnivore Restoration, Luke E. Painter, Robert L. Beschta, Eric J. Larsen, William J. Ripple
Aspen Bibliography
Quaking aspen (Populus tremuloides) recruitment during the 1980s–90s was suppressed by Rocky Mountain elk (Cervus canadensis) herbivory on winter ranges in the Yellowstone region, and saplings (young aspen taller than 2 m) were rare. Following the 1995–96 reintroduction of gray wolves (Canis lupus), browsing decreased and sapling recruitment increased in Yellowstone National Park. We compared aspen data from inside the park to data collected in three winter ranges outside the park. For most areas, the percentage of young aspen browsed annually was 80–100% in 1997–98, decreasing to 30–60% in 2011–15. Sapling recruitment was inversely …
Hydra Effects In Stable Communities And Their Implications For System Dynamics, Michael H. Cortez, Peter A. Abrams
Hydra Effects In Stable Communities And Their Implications For System Dynamics, Michael H. Cortez, Peter A. Abrams
Mathematics and Statistics Faculty Publications
A hydra effect occurs when the mean density of a species increases in response to greater mortality. We show that, in a stable multispecies system, a species exhibits a hydra effect only if maintaining that species at its equilibrium density destabilizes the system. The stability of the original system is due to the responses of the hydra-effect species to changes in the other species’ densities. If that dynamical feedback is removed by fixing the density of the hydra-effect species, large changes in the community make-up (including the possibility of species extinction) can occur. This general result has several implications: (1) …
Predation Threat Alters Composition And Functioning Of Bromeliad Ecosystems, Edd Hammill, Trisha B. Atwood, Diane S. Srivastava
Predation Threat Alters Composition And Functioning Of Bromeliad Ecosystems, Edd Hammill, Trisha B. Atwood, Diane S. Srivastava
Wildland Resources Faculty Publications
Predators can have dramatic effects on food web structure and ecosystem processes. However, the total effect of predators will be a combination of prey removal due to consumption and non-consumptive effects (NCEs) mediated through changes to prey behavioral, morphological, or life history traits induced to reduce predation risk. In this study, we examined how consumptive and NCEs alter community composition and ecosystem function using the aquatic ecosystem housed within tropical bromeliads. We allowed the recolonization of emptied bromeliads containing either no predators, caged predators (NCEs only), or uncaged predators (NCEs and consumptive effects) and recorded densities of all macro-invertebrates, microbial …