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Document Type

Thesis - University Access Only

Award Date

2015

Degree Name

Master of Science (MS)

Department

Natural Resource Management

First Advisor

Lan Xu

Second Advisor

Gary E. Larson

Abstract

Native tallgrass prairie is becoming increasingly rare due to conversion and degradation, putting pressure on endemic prairie species such as the federally threatened Dakota skipper butterfly (Hesperia dacotae). To develop a conservation plan for the butterfly in South Dakota, accurate vegetation classification, mapping, and characterization are critical. The objectives of this study were to 1) rank prairie condition, 2) classify and map upland prairie, 3) characterize and compare vegetation at Dakota skipper inhabited and formerly inhabited sites, and 4) identify potential Dakota skipper habitat within a 225 mi2 (58,275 hectares) study area of the SD Prairie Coteau. Condition metrics were developed following the NatureServe and Minnesota County Biological Survey (MCBS) guidelines. Sixty-seven relevé plots were sampled in upland prairie using the MCBS relevé sampling protocol and classified using multivariate analysis. Characterization of habitat was conducted using 50-m transects subjectively placed at 8 inhabited sites and 4 formerly inhabited sites. Cover by species using modified Daubenmire classes was estimated in six 1-m2 quadrats placed every 10 m on alternate sides of transects. During butterfly flight time, flowering stems were counted along transects in a two-meter belt. Vegetation composition between inhabited and formerly inhabited sites was compared using multivariate analysis and Mann-Whitney U tests. A two-dimensional NMS solution of the phytosociological data found that axis one represented a moisture gradient (r = .55), while management regime influenced axis two (r = .22). Three plant communities, Upland Dry Prairie, Dry-Mesic Prairie and Mesic Prairie, were revealed using flexible beta (β = -.025) and Sørenson distance, and were mapped according to associated USDA ecological sites. The results of the vegetation comparison at inhabited and formerly inhabited sites showed no clear pattern, indicating that other factors like management history and critical minimum size may play a role in population extirpation. Potential habitat was identified by intersecting USDA ecological sites where Dakota skippers have been located with an untilled grassland layer in ArcGIS. The classification and mapping of upland communities and the potential habitat layer will provide a guide to future Dakota skipper surveys and aid in developing a recovery plan at the landscape scale.

Description

Includes bibliographical references (pages 94-99)

Format

application/pdf

Number of Pages

143

Publisher

South Dakota State University

Rights

Copyright © 2016 Diane M. Narem

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