Date of Award

Spring 2014

Degree Name

Master of Science (MS)

Department

Biology

Advisor

Dr. Elmer Finck

Abstract

Grassland birds have declined more rapidly than any other avian taxa in North America. While woody encroachment is often cited as a threat, some grassland-dependent species requiring habitat with scattered trees or shrubs also are declining at statistically significant rates. To better understand the ecological costs and benefits of woody vegetation from a brush management perspective, I studied bird-habitat associations along a canopy cover gradient of eastern redcedar (Juniperus virginiana). Habitat associations were tested by the comparing the relative abundance of breeding birds between 3 habitat treatment levels (0% eastern redcedar canopy cover [open grassland], < 5% eastern redcedar canopy cover [light encroachment], and > 5-25% eastern redcedar canopy cover [moderate encroachment]). Data were collected by repeated point count sampling in mixed-grass and sand prairie habitats of Barton County, Kansas from 2011 to 2012. At the community level, bird response patterns were attributed to habitat preferences and nest placement. Ground-nesting species associated with grassland-forb habitat were most abundant in open grassland sites and decreased with increasing eastern redcedar canopy cover. In contrast, species associated with grassland-shrub and savanna habitats were associated positively with eastern redcedar canopy cover. Patterns in the bird community were further examined with cluster analysis and non-metric multidimensional scaling. Avian species-level responses were assessed with canonical correspondence analysis, which indicated that eastern redcedar canopy cover explained most of the variation in the bird abundance. Abundance models and analysis of variation (ANOVA) further elucidated the significance of response patterns and species distributions along the canopy cover gradient. Considering the diverse habitat requirements of grassland birds, resource managers should consider how conservation practices for one species might affect others.

Rights

Copyright 2014 Scott W. Schmidt

Library Call Number

LD2652 .T5 B5 S357 2014

Comments

Notice: This material may be protected by copyright law (Title 17 U.S. Code).

Included in

Biology Commons

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