Thesis
Influence of artificial canopy gaps on wildlife and understory in young coastal temperate coniferous forests of the Pacific Northwest
Washington State University
Master of Science (MS), Washington State University
2018
Handle:
https://hdl.handle.net/2376/103466
Abstract
Forest managers have begun to incorporate ecological silvicultural practices that mimic natural disturbance to supply habitat for forest dependent wildlife through artificial snag-gap creation in dense second-growth forests. However, the efficacy of those practices for enhancing biodiversity remain poorly studied. We studied pileated woodpecker (Dryocopus pileatus) use to determine the factors that are driving use/non-use of artificially created snag-gaps. Additionally, we studied understory vegetation in created gaps and pseudo-gaps to determine if plant species cover and diversity was affected by the increase of canopy openings in young coastal forests. We collected data on foraging sign and understory vegetation data from 2015-2016 across the Spada Lake research area located in eastern Snohomish County, Washington. We analyzed the data on woodpecker foraging sign with logistic and negative binomial regression to address three questions related to pileated woodpecker use of created snag-gaps: 1) what are the characteristics of snag-gaps and the landscape surrounding snag-gaps that were correlated with presence and intensity of foraging sign, 2) what are the characteristics of trees within snag-gaps that were associated with presence or intensity of foraging sign, and 3) how does use of artificial snag-gaps compare to use of pseudo-gap locations within the forest environment. We determined if understory species diversity and ground cover was different in created snag-gaps and determined if fragmentation of the created snags had begun to occur as a function of height and DBH reductions. We found that pileated foraging use was strongly associated with date of gap, number of trees in gap, elevation and smaller DBH sizes, and that created gaps were receiving more use than pseudo-gaps. Understory vegetation cover was higher in gaps than pseudo-gaps, but Shannon diversity was not significantly different. We did not find evidence that snags are beginning to fragment, but methodological restrictions to this analysis suggest that results should be viewed with caution. Creation of artificial canopy gaps are likely to result in more foraging opportunities for pileated woodpeckers, larger percent cover of understory vegetation over time and may contribute to increasing structural and organismal biodiversity in this intensively managed forest landscape.
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Details
- Title
- Influence of artificial canopy gaps on wildlife and understory in young coastal temperate coniferous forests of the Pacific Northwest
- Creators
- Landon James Charlo
- Contributors
- Daniel H. Thornton (Degree Supervisor)Mark Ellyson Swanson (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525113901842
- Language
- English
- Resource Type
- Thesis