Browsing by Author "Kral, Katherine Claire-Ann"

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Impact of Wildfire and Targeted Grazing Effects on Northern Great Plains Range and Pasture Lands
(North Dakota State University, 2015) Kral, Katherine Claire-Ann
The Grand River District in South Dakota has a high proportion of underutilized crested wheatgrass within native rangelands. Prescribed fire is rarely used for management; although, there is a strong evolutionary relationship with fire and grazing. Our project entailed two studies, the first looking at targeted grazing with cattle and second the effects of an April wildfire on plant species composition, basal cover, and phytomass production. The wildfire and targeted grazing did not affect (p > 0.05) plant species composition or phytomass production four and 16 months after treatment (MAT). Targeted grazing increased (p ≤ 0.05) crested wheatgrass utilization, but did not reduce (p >0.05) basal or canopy cover. Fire was ineffective (p > 0.05) at decreasing crested wheatgrass frequency. Fire increased (p ≤ 0.05) bare ground and decreased (p ≤ 0.05) litter cover four and 16 MAT. Multiple treatments may be more effective at controlling crested wheatgrass.
Method Selection and Estimating Densities for Grassland Butterflies in the Mixed-Grass Prairie
(North Dakota State University, 2018) Kral, Katherine Claire-Ann
Grassland butterflies contribute to the larger group of pollinating insects that are vital for continued plant production and food security in agroecosystems. However, grassland butterflies, along with overall biodiversity, are experiencing widespread declines due to global change factors such as landscape fragmentation, climate change, and agricultural intensification. Research and conservation efforts have therefore increased to mitigate dramatic declines of grassland butterflies. Yet, a large amount of baseline information in unknown for butterflies in the mixed-grass prairie region of the Northern Great Plains, especially for obligate species that wholly depend on grasslands to complete their life cycle. We initiated a study to increase the baseline knowledge and availability of rigorous data to inform conservation by investigating 1) butterfly survey methodology, 2) local and landscape influences on butterfly density, 3) invasive plant species impacts on butterfly communities, and 4) butterfly behavior responses to vegetation. We found that visual encounter surveys (VES) and line-transect distance sampling (LTDS) were complementary methods that should be used in butterfly research to improve the availability of quantifiable data. Even though VES were more efficient at detecting individual butterflies, LTDS provided a rapid way to estimate true density estimates for butterflies. Using LTDS density estimates to model species responses to local and landscape variables, we determined that maintaining large grasslands at the landscape level and promoting heterogeneous plant communities and structure at the local level would help conserve obligate grassland butterflies. One way to promote heterogeneous plant communities is to reduce the cover of invasive plant species. Otherwise, flowering forb and plant species richness decline and butterfly communities shift to fewer obligate butterflies. We can better understand butterfly species’ declines by incorporating behavioral surveys at the site level. In doing so, we found that monarch behaviors associated with utilizing a site (e.g., nectaring, ovipositing) did not increase as milkweed (obligate host plant) cover increased because nectar resource availability decline. Overall, maintaining large, heterogeneous grasslands and identifying management strategies like fire and grazing to increase host and nectar resource availability will benefit the largest number of grassland butterflies.