Master of Science, The Ohio State University, 2007, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2020, Environment and Natural Resources

Confronted with threats of habitat loss and climate change, birds that inhabit open-lands such as grasslands and shrublands are among the most rapidly declining groups of birds across North America. One such bird is the Northern bobwhite (Colinus virginianus; hereafter bobwhite) which inhabits heterogeneous landscapes that typically consist of shrubland, grassland, and early-successional forests. Bobwhites are declining at an alarming rate across most of their range, largely due to habitat loss from intense production agriculture. Populations along the northern periphery of bobwhite range are secondarily imperiled by high mortality from severe winter weather. Because bobwhites are a socially and economically important gamebird, there has been great interest from a variety of stakeholders to maintain suitable habitat and promote sustainable populations. As a result of the conservation attention they receive, bobwhite conservation has the potential to benefit non-target songbirds with similar land cover requirements. The umbrella species concept suggests that benefits will accrue to non-target species if viable bobwhite populations are maintained through habitat conservation. The future viability of bobwhite populations is in question in Ohio, so a comprehensive demographic study is needed to estimate probability of population persistence under a variety of future weather and population viability analysis (PVA) scenarios. The first part of my thesis focuses on landscape-scale characteristics that influence bobwhite occupancy in Ohio, and whether occupancy by other open-land species is positively predicted by bobwhite occupancy. The second part of my thesis focuses on projecting population dynamics of bobwhite in Ohio in response to future winter weather and PVA scenarios. I obtained bird survey data from the Ohio Breeding Bird Atlas (2006–2011). I used land cover data (NLCD 2011) to calculate compositional and configurational landscape metrics within a 630 m radiu (open full item for complete abstract)

Committee: Robert Gates (Advisor); Stephen Matthews (Advisor); Peterman William (Committee Member) Subjects: Ecology; Wildlife Conservation

Bachelor of Arts (BA), Ohio University, 2024, Environmental Studies

Grassland birds have narrow habitat requirements that are influenced by food availability, habitat composition, and habitat structure. Because survival is influenced by habitat quality and availability, understanding habitat requirements is critical for conservation. I determined how Henslow's Sparrows (Centronyx henslowii) use grassland habitat in the breeding season. In the past 10 years, technology advancements have allowed researchers to study the habitat use and movement ecology of understudied birds, such as grassland birds. I deployed nanotags on 47 adult Henslow's Sparrows at two sites in southern Ohio to determine home range size and habitat use in relation to distance to edge and shrub, as well as the post-breeding dispersal and migratory timing. I predicted that Henslow's Sparrows would use core grassland habitat and avoid edge and shrubs. I found no difference in 95 % home range size between female (0.10 ± 0.03 ha) and male (0.32 ± 0.18 ha) Henslow's Sparrows. Henslow's Sparrows used shrubs when available and edge habitat as refugia after disturbance. I also found that Henslow's Sparrows use fields into August, past dates typically recommended for disturbance (e.g., mid to late July), which suggests the need to leave corridors and patches for refugia after management such as mowing or burning. I determined the fall migratory departure timing of 13 Henslow's Sparrows. I found that Henslow's Sparrows are at risk for entanglement which resulted in mortality of two birds. A third bird found entangled was found alive, entangled in vegetation, and was released after I removed the nanotag. I also found that 24 Henslow's Sparrows were able to remove nanotags and several damaged their nanotags. While I do not recommend the use of nanotags on this species in future studies, my study did result in determining fall migratory departure timing of Henslow's Sparrows in Ohio which was previously unknown.

Committee: Kelly Williams (Advisor) Subjects: Animals; Biology; Ecology; Environmental Studies; Organismal Biology; Wildlife Conservation; Wildlife Management; Zoology

Doctor of Philosophy, The Ohio State University, 2022, Environmental Science

Tropical savannas support globally important biological diversity and provide a variety of cultural and economic ecosystem-services to humans. As mosaic landscapes, they are characterized by the coexistence of woody and grassy habitats which are strongly regulated by abiotic gradients (e.g., soils, climate) and local disturbance regimes (e.g., fire, flooding and grazing). Consequentially, savannas are inherently dynamic over a variety of scales and provide an array of temporal and spatial ecological niches for wildlife. However, tropical savannas and their ecological functions have been widely degraded by intensifying human land-use and are threatened by impending climate change. Unfortunately, our scientific understanding of savanna ecology is currently limited, impeding development of appropriate conservation approaches. This is especially true of Neotropical systems. This dissertation provides new research, carried out within the Beni, a seasonally flooded Neotropical savanna in Bolivia, that aims to address critical knowledge gaps in savanna ecology. This research will contribute to developing sustainable land management and restoration initiatives to secure and protect savanna ecosystems for people and wildlife. The overarching aim was to understand how ecological (flooding) and agricultural (managed fire and cattle grazing) disturbance influences habitats and wildlife in Beni. To achieve this, three specific objectives were identified: 1) understand how restoration, through cessation of long-term cattle grazing impacts (i) regeneration, (ii) understory structure and composition, and (iii) abundance and diversity of large mammals and nocturnal birds, within the regions' naturally patchy gallery forests; 2) examine how compounded disturbance from flooding and fire shapes the distribution of woody plants and habitats across a savanna-grassland mosaic; and 3) determine functional responses of avian biodiversity to livestock removal across a savanna-grassland ec (open full item for complete abstract)

Committee: G. Matt Davies (Advisor); Christopher Tonra (Advisor); Stephen Matthews (Committee Member); Kaiguang Zhao (Committee Member) Subjects: Conservation; Ecology; Environmental Science; Range Management; Wildlife Conservation