First Advisor

Adams, Rick A.

Document Type

Dissertation

Date Created

5-2023

Department

College of Natural and Health Sciences, Biological Sciences, Biological Sciences Student Work

Abstract

Climate change has led to increased severity and frequency of forest disturbances globally which would predictably alter species compositions in affected habitats. Bats, as important bioindicators of ecosystem health, are known to respond to changes in habitat structure and prey composition. This dissertation describes how a forest disturbance event and ensuing successional changes altered the structure of bat-associated food web components along the highly biodiverse Front Range of Colorado. Mountain pine beetles (MPB) are important drivers of forest regeneration when populations are at background levels, however, unprecedented outbreaks of MPB populations in recent decades have severely impacted over 1.3 million hectares of lodgepole pine forests in Colorado. This has resulted in widespread structural changes in these forest habitats that comprise approximately 7% of the land area in the Rocky Mountains, and there are unclear patterns in the short-term shifts occurring in vegetation community composition following the recent MPB outbreak. The first project reported here (Chapter II) examines the community structure of vegetation in lodgepole pine forests after MPB-kill and relates time-since-kill and other environmental factors to ensuing secondary successional changes using a non-metric multidimensional scaling ordination. The second project (Chapter III) investigates how these shifting baselines in vegetation community structure alter bat-associated food web interactions in lodgepole pine ecosystems. The third project (Chapter IV) investigates activity patterns of tri-colored bats in these novel MPB-killed habitats and quantifies what site and environmental factors are influencing these patterns. Tri-colored bats (Perimyotis subflavus) are extending their distributional range westward in the United States including into the Front Range of Colorado. In sum, these projects describe how secondary successional patterns in lodgepole pine forests after severe beetle-kill disturbance shapes a diverse assemblage of vegetation, bats, and insects. This knowledge will help resource managers and biologists to better understand and plan for community and assembly-level management.

Extent

194 pages

Local Identifiers

Bevan_unco_0161D_11132.pdf

Comments

Spring 2023 Graduate Dean's Citation for Outstanding Thesis, Dissertation, and Scholarly Project

Rights Statement

Copyright is held by the author.

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