Document Type

Thesis - Open Access

Award Date

2012

Degree Name

Master of Science (MS)

Department / School

Natural Resource Management

First Advisor

Jonathan A. Jenks

Second Advisor

David W. Willis

Abstract

Grassland established through the Conservation Reserve Program (CRP) has provided critical habitat for many wildlife species. Recent declines in CRP-grassland acreage attributed to changes in federal enrollment policy, increased biofuels production, and commodity prices may have negative consequences on wildlife populations. Conservation Reserve Program habitats have increased availability of quality nesting and over-winter cover for pheasants (Phasianus colchicus) in regions where large-scale conversions of native grasslands to cropland have occurred. The purpose of this study was to quantify the effect of CRP-grasslands on pheasants across a large geographic region. Primary objectives of the study were to determine presence/absence of pheasants and produce a habitat-based model predicting change in pheasant abundance. We used logistic regression and negative binomial regression to evaluate the influence of CRP-grassland availability on pheasant presence and abundance in South Dakota during 2006−2010 using survey data from 84 brood-survey routes. We generated pseudo-absence locations in equal proportion to hen pheasant (n = 5,876) and brood locations (n = 4,829) and used a logistic regression to model presence/absence of a hen pheasant and a pheasant brood in eastern South Dakota. We developed 2 sets of models; 1) locations where ≥1 hen pheasant was present and 2) locations where ≥1 hen pheasant with a brood was present at 2 spatial scales; a 500 and 1,000-m buffer around an observation. The top model for hen pheasants and pheasant broods at a 1,000-m scale was [Mean Patch Size + %GRASS + %Hay/Alfalfa + Landscape Shape Index + Patch Density + %CRP-grassland + CRP Mean Patch Size + CRP Patch Density + Spring Precipitation + Row Crop Mean Patch Size + Winter Snowfall + %Wetland + %Wheat + Woody Vegetation Patch Density]. Probability of the presence of a pheasant brood increased by 1.01 (95% CI = 1.003−1.023) for every 1 ha increase in CRP-grassland and probability of the presence of a hen pheasant increased by 1.02 (95% CI = 1.016−1.028) for every 1 ha increase in CRP-grassland. We examined 9,724 (n = 23,975 pheasants) spatially explicit pheasant locations using negative binomial regression to predict the response of pheasant abundance to changes in habitat distribution and percentage in eastern South Dakota. Our top model [%CRP + CRP Patch Density + %Row Crop + %Row Crop2 + %GRASS + GRASS Patch Density + Hay/Alfalfa + Hay/Alfalfa Patch Density + WHEAT] indicated CRP grasslands, other reproductive habitats associated with pheasant broods, and row crop agriculture influenced pheasants greatest across a large, regional scale. Based on our top model, when all other variables in the model were held constant at their means, pheasant counts increased by 5 (95% CI = 2.99–5.93) birds for every 94.3 ha increase of CRP-grassland. Presence of pheasants was strongly influenced by CRP-grasslands in areas dominated by row crop agriculture. CRP-grassland had a lesser effect predicting pheasant abundance, although the effect may have been diluted by the large variation in land use across eastern South Dakota as well as varying spring precipitation and winter snowfall. This study provided useful insight in the regional influence of the CRP on pheasants in eastern South Dakota. Results will be used to improve pheasant management in South Dakota and assist South Dakota Department Game, Fish and Parks when making decisions concerning Farm Bill dependent habitats and pheasant management. Conservation Reserve Program-grasslands had a positive effect on pheasants in both modeling efforts across eastern South Dakota. However, continued evaluation of the CRP and other land use programs should provide further insight to understanding regional differences in land management on pheasants in eastern South Dakota.

Library of Congress Subject Headings

Ring-necked pheasant -- Habitat -- South Dakota
Grassland ecology -- South Dakota
Conservation Reserve Program (U.S.)

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

187

Publisher

South Dakota State University

Rights

Copyright © 2012 Joshua J. White. All rights reserved.

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