Whitebark pine stand condition, tree abundance, and cone production as predictors of visitation by Clark's nutcracker
| Autor: | Diana F. Tomback, Michael B. Wunder, Shawn T. McKinney, Lauren E. Barringer |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Nutcrackers
Evolutionary Processes Seed dispersal Endangered species Plant Pathogens lcsh:Medicine Plant Science Dendroctonus Trees Behavioral Ecology Abundance (ecology) Plant-Environment Interactions Animals Passeriformes lcsh:Science Biology Ecosystem Conservation Science Population Density Evolutionary Biology Multidisciplinary Models Statistical biology Ecology Plant Ecology lcsh:R Endangered Species food and beverages Sciuridae Agriculture Forestry Plant Pathology Plants biology.organism_classification Pinus Pinus albicaulis Species Interactions Community Ecology Evolutionary Ecology Threatened species lcsh:Q Conifer cone Research Article Coevolution |
| Zdroj: | PLoS ONE PLoS ONE, Vol 7, Iss 5, p e37663 (2012) |
| ISSN: | 1932-6203 |
| Popis: | Background: Accurately quantifying key interactions between species is important for developing effective recovery strategies for threatened and endangered species. Whitebark pine (Pinus albicaulis), a candidate species for listing under the Endangered Species Act, depends on Clark’s nutcracker (Nucifraga columbiana) for seed dispersal. As whitebark pine succumbs to exotic disease and mountain pine beetles (Dendroctonus ponderosae), cone production declines, and nutcrackers visit stands less frequently, reducing the probability of seed dispersal. Methodology/Principal Findings: We quantified whitebark pine forest structure, health metrics, and the frequency of nutcracker occurrence in national parks within the Northern and Central Rocky Mountains in 2008 and 2009. Forest health characteristics varied between the two regions, with the northern region in overall poorer health. Using these data, we show that a previously published model consistently under-predicts the proportion of survey hours resulting in nutcracker observations at all cone density levels. We present a new statistical model of the relationship between whitebark pine cone production and the probability of Clark’s nutcracker occurrence based on combining data from this study and the previous study. Conclusions/Significance: Our model clarified earlier findings and suggested a lower cone production threshold value for predicting likely visitation by nutcrackers: Although nutcrackers do visit whitebark pine stands with few cones, the probability of visitation increases with increased cone production. We use information theoretics to show that beta regression is a more appropriate statistical framework for modeling the relationship between cone density and proportion of survey time resulting in nutcracker observations. We illustrate how resource managers may apply this model in the process of prioritizing areas for whitebark pine restoration. |
| Databáze: | OpenAIRE |
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