Determining the timing of willow shrub dieback using epicormic shoots

Kaczynski, Kristen M.; Cooper, David J.

doi:10.1007/s11273-014-9378-y

Cited by 1 publication

(3 citation statements)

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“…Beaver are unique herbivores whose complex foraging behavior harvests willow close to the ground, often inducing basal sprouting (Allen , Peinetti et al. , Kaczynski and Cooper ). Willow are highly adapted to repeated harvest and when in good condition sprout new basal stems in proportion to the number cut by beaver (Kindschy ) and increased net primary productivity (Baker et al.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, research to date in the park has limited indicators of wetland condition to herbaceous understory diversity, which can be difficult to interpret (Chew 1982, Gough andGrace 1998), or woody vegetation composition and structure, which may not reflect contemporary wetland integrity. Perhaps most importantly, previous analyses of ungulates, beavers, and wetlands in RMNP have not quantitatively examined the network of connections that allows a more complete description of the drivers controlling ecosystem condition (kaczynski and Cooper 2013). The demonstrated influence of multiple drivers on wetland condition argues that such an analysis will inform important changes in wetlands management strategies in the park.…”

Section: Study System and Backgroundmentioning

confidence: 99%

“…Second, persistent historical beaver habitat modifications can also directly and indirectly increase shrub production. Beaver are unique herbivores whose complex foraging behavior harvests willow close to the ground, often inducing basal sprouting (Allen 1983, Peinetti et al 2009, kaczynski and Cooper 2015a.…”

Section: Degree Of Invasionmentioning

confidence: 99%

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Using structural equation modeling to link human activities to wetland ecological integrity

et al. 2016

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Abstract. The integrity of wetlands is of global concern. A common approach to evaluating ecological integrity involves bioassessment procedures that quantify the degree to which communities deviate from historical norms. While helpful, bioassessment provides little information about how altered conditions connect to community response. More detailed information is needed for conservation and restoration. We have illustrated an approach to addressing this challenge using structural equation modeling (SEM) and long-term monitoring data from Rocky Mountain National Park (RMNP). Wetlands in RMNP are threatened by a complex history of anthropogenic disturbance including direct alteration of hydrologic regimes; elimination of elk, wolves, and grizzly bears; reintroduction of elk (absent their primary predators); and the extirpation of beaver. More recently, nonnative moose were introduced to the region and have expanded into the park. Bioassessment suggests that up to half of the park's wetlands are not in reference condition. We developed and evaluated a general hypothesis about how human alterations influence wetland integrity and then develop a specific model using RMNP wetlands. Bioassessment revealed three bioindicators that appear to be highly sensitive to human disturbance (HD): (1) conservatism, (2) degree of invasion, and (3) cover of native forbs. SEM analyses suggest several ways human activities have impacted wetland integrity and the landscape of RMNP. First, degradation is highest where the combined effects of all types of direct HD have been the greatest (i.e., there is a general, overall effect). Second, specific HDs appear to create a "mixed-bag" of complex indirect effects, including reduced invasion and increased conservatism, but also reduced native forb cover. Some of these effects are associated with alterations to hydrologic regimes, while others are associated with altered shrub production. Third, landscape features created by historical beaver activity continue to influence wetland integrity years after beavers have abandoned sites via persistent landforms and reduced biomass of tall shrubs. Our model provides a system-level perspective on wetland integrity and provides a context for future evaluations and investigations. It also suggests scientifically supported natural resource management strategies that can assist in the National Park Service mission of maintaining or, when indicated, restoring ecological integrity "unimpaired for future generations."

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Section: Discussionmentioning

confidence: 99%

Section: Study System and Backgroundmentioning

confidence: 99%