Influence of vegetation structure and landscape context on the occupancy of shrubland birds

Van den Bosch, Kyle

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https://hdl.handle.net/2142/102922 Copy

Description

Title

Influence of vegetation structure and landscape context on the occupancy of shrubland birds

Author(s)

Van den Bosch, Kyle

Issue Date

2018-11-30

Director of Research (if dissertation) or Advisor (if thesis)

• Ward, Michael P.
• Benson, Thomas J.

Department of Study

Natural Res & Env Sci

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Shrubland birds
• occupancy
• vegetation structure
• landscape

Abstract

Across the guild of shrubland birds, some species have been experiencing long-term population declines while other have been increasing. One potential reason for these differences is that various shrubland bird species prefer different types of shrubland habitat and some habitats are more common than others. However, we lack a clear understanding of the attributes of shrublands that shrubland birds prefer. Specifically, we lack information on how the percent shrub cover, the proportion of shrubs comprised of non-native shrubs, the patchiness of shrubs, and the surrounding landscape context influence occupancy (the probability that a given species will be at a site) of shrubland birds. To better understand these relationships I used bird survey and vegetation data from a long-term monitoring program that randomly monitored shrublands across the state of Illinois. I examined the influence of landscape and site-level variables on the occupancy of 22 shrubland bird species. Generally, the proportion of non-native shrubs at a site had little influence on shrubland bird occupancy. Shrubland birds responded positively to both the percent shrub cover and to the patchiness of shrubs; however the strength of the relationship differed between species. Over half (6/10) of the species that are experiencing population declines in the region (as determined by Breeding Bird Survey data) responded strongly to the patchiness of the shrubs, whereas, only 3 of the 12 shrubland species whose populations were either stable or increased responded to the patchiness of shrubs. The difference in population trends across the suite of shrubland birds may be driven by preferences for patchy shrublands. When creating or managing shrubland habitat, it is important to consider that the presence of shrubs is not enough and that the patchiness of shrubs may be important for a subset of shrubland birds.

Graduation Semester

2018-12

Type of Resource

text

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http://hdl.handle.net/2142/102922

Copyright and License Information

Copyright 2018 Kyle Van den Bosch

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