Document Type

Dissertation - Open Access

Award Date

2021

Degree Name

Doctor of Philosophy (PhD)

Department

Natural Resource Management

First Advisor

Robert C. Lonsinger

Second Advisor

Andrew J. Gregory

Keywords

Grassland bird, Habitat fragmentation, Landscape matrix, Nest-site selection, Resource selection, Survival

Abstract

Habitat loss and fragmentation are the greatest threats to wildlife conservation. Grasslands are among the most threatened ecosystems worldwide. The large-scale conversion of North American grasslands to cultivation has been strongly associated with declines of grassland bird populations. The ring-necked pheasant (Phasianus colchicus) is a common grassland bird which is negatively impacted by the conversion of grassland to cropland. Though pheasants are non-native to South Dakota, they have become naturalized in most of the state. However, with increases in agricultural intensification in South Dakota, indices of pheasant abundance from brood route surveys suggest that pheasant populations have declined to historically low levels throughout the state. Over a period of 3 years (2017-2019), we i) examined pheasant space use in multiple seasons, ii) quantified nest-site selection and brood-site selection, and iii) estimated adult survival during breeding season. Additionally, we used annual count data from pheasant brood routes from 1993-2016 to identify high (HotSpot) and low (ColdSpot) pheasant productivity areas and their landscape attributes. Lastly, we used survey data from 2011- 2019 and N-mixture modeling to identify landscape attributes influencing pheasant abundance. We found that pheasant HotSpots were better explained by landscape configuration (patch connectivity, and number of grassland patches) rather than proportion of grassland. Pheasant abundance was also impacted by area under grassland, area under small grain, and connectivity of rowcrop patches. Pheasants’ space use varied slightly among seasons. Pheasants preferred grassland, Conservation Reserve Program (CRP), and road-side cover during both winter and breeding seasons. During winter, pheasant space use was also impacted by distribution of wetland, forest and rowcrop in the landscape. Our result demonstrated the importance of vegetation structure and percent grass cover on nest-site selection at the microhabitat scale. At the macrohabitat scale, pheasant nest-site selection was also positively associated with area under CRP, area under small grain, and contiguity of grassland patches. Pheasants tended to avoid areas with high relative abundance of mammalian predators. At microhabitat scale, nest survival was negatively impacted by percent litter cover and estimated nest survival was 68% (95% CI = 57%-77%). Proximity to rowcrop and small grain best explained nest survival at macrohabitat scale and estimated nest survival was 46% (95% CI = 33%- 60%). We found that at a local scale, brood-site selection was positively associated with arthropod biomass and vegetation structure while at a broader scale, pheasants with broods tended to select for sites with less area under rowcrop and more isolated rowcrop patches. Broods in our study area had low survival (0.22; 95% CI = 0.10-0.52). Average daily temperature and precipitation during first two weeks since hatch best explained brood survival. We estimated pre-nesting and nesting season adult survival as 0.85 (95% CI = 0.80-0.91) and 0.72 (95% CI = 0.66-0.81), respectively. Our survival analysis suggested habitat heterogeneity to be an important predictor of adult survival. Area of CRP grassland, proximity to road, and proximity to small grain positively influenced survival during the breeding season. Adult survival was negatively impacted by relative abundance of mammalian predators in the area. We recommend that managers work closely with landowners and facilitate public x private landscape conservation cooperatives to balance the needs of pheasants with the needs of the landowners. For example, cooperative farming agreements can be utilized whereby private landowners plant crops in a rotation specified by managers to create a landscape mosaic maximally beneficial to pheasants; in turn, landowners may receive either direct payments or tax credits for their participation and adherence to management planting guidelines. These findings provide intriguing insights into the debate regarding the merits of the importance of managing habitat area versus landscape characteristics (e.g., connectivity or number of patches).

Number of Pages

277

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

Share

COinS