Many landscapes are experiencing extensive habitat fragmentation, which is habitat loss that isolates populations and reduces abundance. Over 70% of the Earth's forests are within 1 km of the forest edge, and most of the remaining forests are vulnerable to anthropogenic disturbance. In contemporary landscapes, species are confronting multiple interacting stressors, including habitat fragmentation and climate change. Climatic factors govern the distribution patterns of species. Rapid anthropogenic climate change has already caused range contractions and local extinctions across many species. Species that were well-adapted to historical climates may not be able to survive when faced with a novel climate. Habitat fragmentation and climate change are happening simultaneously but are typically studied in isolation. To generate robust predictions about population response to global change, we need to evaluate the synergistic consequences of climate change and fragmentation. Climate change has shifted distribution patterns, imposed novel selection, disrupted local adaptation, and altered species interactions. Extensive research on habitat fragmentation has documented reductions in gene flow and genetic diversity. My research seeks to unite these fields by evaluating the adaptive and migratory potential of fragmented populations in the context of climate change. My research focuses on Pityopsis graminifolia var. graminifolia (Michx.) Nutall Fernald (Asteraceae), a common perennial native to the southeastern US. will investigate how habitat fragmentation influences plant population persistence under global change by addressing the following question: What are the demographic consequences of habitat fragmentation under climate change conditions? I hypothesize that smaller, more isolated populations will be less likely to persist because they have decreased potential to adapt to climate change as a result of reduced gene flow. Under this hypothesis I expect fragmented populations to maintain lower population growth rates (λ) than intact populations in contemporary environments. To test the hypothesis that increased habitat fragmentation decreases population growth rates, I have initiated an annual demographic survey of fragmented and unfragmented populations of P. graminifolia. At each site, I established demographic plots 2019 to estimate population density and collect data on vital rates. I have used integral projection models to estimate population growth rate to determine whether intact populations are more stable and more likely to persist under contemporary conditions than fragmented populations. This study could direct future conservation practices and policies in a landscape subject to strong habitat fragmentation and rapid climate change.
