Date of Award
12-5-2017
Document Type
Thesis
Degree Name
Biology, MS
First Advisor
Than Boves
Committee Members
Paul Sikkel; Travis Marsico
Call Number
ISBN 9780355488418
Abstract
Over the last 200 years, forests of the eastern United States were largely cleared for industrial and agricultural purposes, and subsequent regrowth has resulted in mostly even-aged, closed canopy stands. Furthermore, dynamic ecological conditions including windthrow, ice storms, floods, fires, tree senescence, and insect outbreaks, which are necessary for maintaining healthy forest ecosystem functions and biodiversity, have become infrequent and/or do not have the same effects in contemporary forests as they did in old growth systems. This has partially led to declines in a number of disturbance-dependent and early-successional avian species, and a need for harvest prescriptions that emulate these important ecological processes. The Lower Mississippi Valley Joint Venture (LMVJV) has created recommendations that implement variable retention harvest (VRH) to achieve desired forest conditions (DFCs) to ameliorate even-aged, closed canopies of bottomland hardwood forests of the Lower Mississippi Alluvial Valley (LMAV) and to benefit a number of species of conservation concern. Here, I report on the short-term effects of VRH management regimes on the numerical response (e.g., density) of the avian community, including avian predators (e.g., corvids, raptors) and the brood parasitic Brown-headed Cowbird (Molothrus ater), and the reproductive response of understory breeding birds by evaluating 2 years of pre-harvest and 2 years of post-harvest data using a Before-After-Control-Impact design. Site level densities of the majority of breeding birds and all nesting guilds increased post-harvest, with the exception of Carolina Wren (Thryothorus ludovicianus), which declined to lower than pre-harvest levels by year-2 post-harvest. Treatment level density of the secondary-cavity nesting guild declined in DFC stands compared to NHC and MS stands, and the majority of individual species declined in MS stands compared to NHC and DFC stands. Understory nest survival and provisioning rates did not change between pre- and post-harvest years; however, rates of brood parasitism increased for the Indigo Bunting (Passerina cyanea) and White-eyed Vireo (Vireo griseus), and a larger proportion of nests were depredated by snakes post-harvest. In the short-term, VRH regimes appear to have mostly positive effects on avian densities, and few negative effects on nest survival, and the underlying ecological processes that impact avian fitness. However, we recommend continued assessment of temporal dynamism of predation, parasitism, and provisioning trends with follow-up studies 5–7 years post-harvest, and assessment of nest survival for other nesting guilds (e.g., canopy, midstory) in response to VRH management strategies. Finally, we recommend implementing VRH prescriptions within the largest, most contiguous available forest tracts within the LMAV, furthest from agricultural edges (i.e., cowbird foraging grounds), rather than within highly fragmented areas to reduce the potential for creating ecological traps.
Rights Management
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Wilcox, Jennifer L., "Emulating Natural Disturbance Using Variable Retention Harvest Regimes: Measuring Short-Term Changes in The Avian Community and Understory Nest Survival" (2017). Student Theses and Dissertations. 544.
https://arch.astate.edu/all-etd/544
