This study took place within the Oak Openings Region, a biodiversity hotspot in northwestern Ohio. The Oak Openings was created during the Cenozoic period, a time where glaciers continuously moved across Ohio, creating valleys and riverbeds. When the Wisconsin glaciers melted back from Ohio around 14,000 years ago, waters were released into multiple lakes with sandy beaches. Overtime, these sandy beaches started to became dunes inundated by rainwater that could not drain past the clayey till and bedrock ground layer. Water that would stand between the clay layer and sandy dunes provided moisture to eventually support oak savanna habitat. Between the sand ridges, rainwater would saturate the land, which created open areas of wet prairie (Higgins, 2003; Grigore, 2004). The combination of oak savanna habitat and open wet prairie gave this region the name of “Oak Openings” (Grigore, 2004).
Today, the Oak Openings looks quite different as a result of the economic development and agricultural pursuits along the Toledo-Detroit corridor. This area is highly fragmented by roads, agricultural fields and urban/residential development. Roughly 45% of the Oak Openings Region contains urban and suburban development and roughly a quarter of the region has been converted to areas of agricultural production (Schetter and Root, 2011). However, there are still remnants of wild lands that exist west and south of the city of Toledo. This area is Ohio’s largest single surficial sand covering which is 1-12 meters thick and consists of wet lowland and sand ridge terrain with elevations up to 210 meters above sea level. This region is approximately 8 kilometers wide and 32 kilometers long (Higgins, 2003; Figure 1) and contains oak savanna, oak woodland and wet prairie habitats on post glacial beach ridges and swales and covers 478 km2 (The Nature Conservancy, 2001; Grigore, 2004; Schetter and Root, 2011).
The Oak Openings Region contains one third of all of Ohio’s endangered plant communities as well as many rare animals and early successional ecosystems. However, only about 10% of the Oak Openings Region is in protected areas (Abella et al., 2007). Early successional ecosystems in this area (e.g. oak savannas and prairies) were historically maintained by disturbances such as fire. Now, these disturbances are mimicked by management activities such as prescribed fires and thinning. In Ohio there are two preserves known as the Oak Openings Preserve and Maumee State Forest, which are the largest protected areas and support many different vertebrate populations and species. However, these two preserves are also highly fragmented by agricultural fields, roadways, railways, and trails that may limit animal movement and increase road mortality. Therefore, it is critical to better understand animal movement and road mortality in this area to promote viable populations, increase our knowledge of vertebrate movement and prevent the killing of vertebrate species by vehicle collisions.
This thesis has two foci, each as the topic of stand-alone chapters. The overarching goal is to predict animal movement and identify the features that may be managed to reduce road mortality, which is likely to be applicable to other reserves in human-dominated landscapes. The objective of the first chapter is to understand what factors influence animal movements and road mortality. Specifically, the first chapter examines how structural features of roads, environmental variables, spatial factors and land cover types can influence vertebrate movement (e.g. mammals, birds, reptiles, amphibians) and road mortality on roads surrounding and within the Oak Openings Preserve and Maumee State Forest. Road surveys as well as visual surveys on trails within both protected areas were utilized to account for animal movement, dispersal and mortality.
The second chapter focuses on mammal movement patterns and road mortality on roads surrounding and within the Oak Openings Preserve and Maumee State Forest. Similar to chapter I, road and visual surveys along trails were utilized to understand mammal movement and mortality. Mammals were found as roadkill more than any other taxa, so it is important to specifically understand what factors influence these trends. Again, structural features of roads, environmental variables, spatial factors and land cover types were all analyzed to understand what influences mammal movement and mortality.