To improve our predictions of the response of plant communities to a warming climate, we study warming events in Earth’s history. The Miocene Climatic Optimum (MCO) spanned between 17-14 Ma. It was a period of warming that corresponded with increased atmospheric carbon dioxide to ~400-600 ppm. Rising atmospheric CO2 and increased temperatures is known to affect plant water-use efficiency (WUE)—the ratio of carbon assimilation to transpirational water loss—and the prevalence of varying ecological strategies within a plant community. This project aims to study the ecological strategy and WUE of several important plant species comprising temperate deciduous forests during the MCO, using exquisitely preserved fossil leaves from the Clarkia Fossil Site in northern Idaho (~15.9 Ma). I measure leaf vein density, which relates to maximum photosynthetic potential and estimate assimilation rates using gas exchange modeling. This model incorporates measures of resistance to stomatal conductance (i.e., stomatal index and pore length) and measures of the extent of CO2 drawdown within the leaf relative to ambient CO2 (i.e., Ci/Ca) using the stable carbon isotopic composition of the fossil leaves. I use these measures to determine the relative ecological and water-use strategies of the various species in these ancient temperate deciduous forests and compare those with similar measures from modern and similar forest types using established plant trait databases (e.g. TRY). By studying the past vegetation of the Pacific Northwest, we are providing an example of how present-day deciduous forests may respond to current anthropogenic changes in CO2.

North America’s forests face significant challenges and stressors that degrade habitat for birds and other wildlife and impair forest health and resiliency, including fragmentation, invasive species, and a lack of age class and other measures of diversity. Wildlife species need intact forested landscapes that include forests with multiple age classes, diverse species of native trees, and complex structure. Long term success in contemporary forest management methods is essential to native wildlife that depend on the abundance of biodiversity and must not only sustain timber resources, but the ecosystem services provided by forest ecosystems in the face of changing climate and disturbance regimes. Arthropods are a critical component of ecosystems because they are the base of the food chain for the majority of breeding forest birds and can be used as bioindicators to infer effect of management on forest biodiversity. To assess the relationship between forest management and insect communities, this study focused on regenerating forests and wetland habitats in the Chippewa National Forest, Minnesota, USA. Malaise traps and branch clippings were used to assess differences in insect communities within stands of fragmented tree communities in regenerating forests and wetland habitats. Malaise traps were deployed for 7-day time periods and clippings taken at the end of the 7-day time period. Insects from clippings and traps were sorted to order and weighed to determine differences in order-level diversity and biomass between sites. This information is an important first step for using arthropod bioindicator groups to effectively assess ecologically sustainable forest management plans.

Previous studies have examined the relationship between biodiversity and ecosystem functioning at the community and ecosystem level; however, there has been little research into the consequences of changes in biodiversity at the species level. The purpose of this research was to investigate the impact of changes in biodiversity on the function of ecosystems in central Texas landscapes at the species level within the mechanism of herbivory. Additionally, the objective of this study was to investigate the influence of global change constraints on the biodiversity-ecosystem functioning relationship. Three species were investigated in this study: Monarda citriodora, Lupinus texensis, and Centaurea americana. Multiple estimates of biodiversity, including phylogenetic diversity, functional diversity, and species richness, were measured to quantify ecosystem functioning. In order to assess the influence of insect herbivory on the plant biodiversity and ecosystem functioning, measurements of herbivory, functional traits, and secondary metabolites were collected inside and outside the insect net. Herbivore damage was assessed using the ImageJ processing program as well as quantitative presence and absence recording. Measures of functional traits collected included maximum plant height, specific leaf area, and leaf chemistry. The results of the study reveal noticeable differences in traits collected across the diversity gradient. There were observable variations in the maximum plant height of a species in a monoculture versus in the twelve species plots. The levels of herbivory within the insect net were lower than the levels outside of the net for all three species.

The interaction between cancer cells and their microenvironment influences tumor proliferation and progression, as well as the response to treatment. A significant component of the microenvironment of most solid tumors are cancer-associated fibroblasts (CAFs). CAFs is one of the most prominent population of stromal cells in breast tumors. As cancer develops, including through metastases, fibroblasts play a crucial role in responding to tissue damage due to cancer cells. Cancer progression has been facilitated by their release of growth factors, extracellular matrix remodeling, and inflammatory responses. This project aims to investigate the expression of extracellular matrix, inflammatory markers and invasion/migration markers in breast microtumors. In this research, we used RNA to examine the extracellular matrix of the mouse breast cancer cell line, 4T1, to the mouse breast stromal cell line 4f in both 2D and 3D cell cultures. We explore the hypothesis that breast microtumors secrete varying amounts of extracellular matrix, inflammatory markers, and invasion/migration markers compared with breast cancer cells cultured in two dimensions. We believe that as microtumors are grown in 2D and 3D, stromal cells intensify the changes observed between the two culture methods.