Browsing by Author "Klein, Julia, advisor"

Now showing 1 - 2 of 2

Open Access
Climate forecasting, climate-resistant tree species selection, and urban canopy planning for a small, semi-arid city
(Colorado State University. Libraries, 2023) Buchholz, Natalie S., author; Klein, Julia, advisor; Boone, Randall, committee member; Ocheltree, Troy, committee member
Globally, there is an increasing shift from rural to urban living, with major implications for the ecosystem services provided by these ecological systems and profound effects on the human communities that continue to migrate to them. Urban canopies and the development of green spaces in the urban environment can mitigate some of the negative effects of urban living such as high Urban Heat Indices (UHI), poor air quality, loss of emotional support from nature, and loss of sense of place. However, the poleward shift of climate envelopes due to climate change will eventually lead to urban canopy collapses as street trees become less suited to their environment. In chapter one of this thesis, I explore this shift and climate-change resistant tree species selections by using WorldClim's current (1971-2000), SSP126 (low emissions) and SSP585 (high emissions) scenarios to generate climate envelope projections for the City of Fort Collins, Colorado in the years 2061-2080. I collected recommended street tree lists from cities that currently exhibit future climate conditions in Fort Collins (hereafter, reference cities) and compared them to the current city of Fort Collins' recommended street tree list. I identified 15 shade trees that have already undergone testing by CSU arborists and are appropriate for immediate planting in Fort Collins, Colorado – these 15 shade tree species comprise the Future Fort Collins Recommended Street Tree list. I identified an additional 21 shade tree species that still require CSU arborist testing for planting suitability – these 21 shade tree species comprise the Future Fort Collins Recommended Street Tree-Test list. The Future Fort Collins Recommended Street Tree and Future Fort Collins Recommended Street Tree-Test lists will inform street tree diversity and planting strategies for the City of Fort Collins, CO, and provide a brief list of species that need further suitability testing by foresters and arborists along the Front Range. Chapter two of this thesis aims to address current canopy inequities in Fort Collins, Colorado, by examining patterns in the city's overall land cover distribution, as well as the built environments and policies that limit canopy expansion. Here I explore canopy and land cover in four census blocks that are at least 25% Hispanic and have a median household income of less than $40k per year. I further dissect these four census blocks into smaller study areas based on zoning type as designated by the City of Fort Collins and Larimer County Assessor's Office. Using a combination of satellite observation and I-Tree canopy analyses I hope to, 1) identify patterns in land and canopy cover across zoning types, and 2) identify factors in the built environment and written policy that limit urban canopy growth in the City of Fort Collins, Colorado. Results will inform canopy care and planting strategies as the city moves to create its first Urban Forest Strategic Plan in the coming years.
Open Access
Timing is important: seasonality of precipitation influences ecosystem properties and response to grazing
(Colorado State University. Libraries, 2012) Dev, Laura, author; Klein, Julia, advisor; Brown, Cynthia, advisor; Blumenthal, Dana, committee member; Hobbs, N. Thompson, committee member
Water availability and grazing are both strong drivers of grassland community structure and function. We know that water limited ecosystems, can be very sensitive to temporal changes in precipitation, influencing important properties including primary production, carbon and nutrient cycling and plant and microbial species composition. However, little is known about how the timing of water availability interacts with grazing. I conducted a global meta-analysis to investigate the importance of precipitation seasonality in determining broad-scale patterns of plant community response to grazing. I focused on the relative importance of climatic factors compared with grazing variables in influencing the effects of grazing on plant species composition and primary production. Locations with more summer precipitation experienced greater grazing-induced changes in species composition. Species composition was more responsive to grazing covariates, whereas production was more responsive to climatic variables, particularly the length of the growing season. I explored potential mechanisms for this pattern by conducting a trait study at a climate change experiment on the Tibetan Plateau. Shifting the timing of water availability toward the winter altered community-level plant traits associated with grazing avoidance and tolerance, and grazing sometimes acted as a feedback. Together, these results provide compelling evidence that the timing of precipitation can interact with grazing to drive changes in plant community structure and function. In light of climate changes that may shift the timing of precipitation in many systems worldwide, these effects are increasingly important to understand.