Current Research
Prairie Phenology Driven by Temperature and Not Moisture in Climate Manipulations Across a Latitudinal Gradient
Paul Reed, on-going research
Plant phenological responses were examined across control, warming, drought and warming plus precipitation treatments at three sites across a latitudinal gradient in the Pacific Northwest, USA. The focal species examined are range-restricted and were planted within, and north of, their current range. Abundance and flowering milestones were monitored across treatments. Seasonal biomass was measured via normalized difference vegetation index (NDVI). Results indicated that temperature was a stronger key control than moisture on phenology at both the population and community level. Warming caused flowering time to advance regardless of range. Results also suggest that survival to reproduction might be a stronger constraint than phenological shifts on the future viability of focal species. On a community-level, warming treatments influenced an earlier peak biomass across all sites. A reduction in growing season length at the southern site, a longer growing season at the northern site, and a net-neutral-length shift in growing season at the central site were observed due to warming.
Conclusions:
1.Warming advanced flowering, regardless of location along latitudinal gradient
2.Warming shortened the growing season at southern site, shifted the season at the central, and lengthened the season at the northern
Warming Advances Flowering Phenology
Phenology of Community Biomass
- Southern:
- Supression of biomass in spring 2017
- Central:
- Increase in biomass from fall 2016-spring 2017
- Supression of biomass in summer 2017
- Northern:
- Increase in biomass from winter-spring 2017
- increase again in fall 2017
Senescence rate:
- Southern>Central>Northern
- Warming>ambient at Central
Past Research
Climate Change Effects on Arbuscular Mycorrhizal Fungi and Prairie Plants Along a Mediterranean Climate Gradient
Hannah Elizabeth Wilson, 2012
The author focused on understanding the effects of climate change on the percentage of roots colonized by arbuscular mycorrhizal fungi (AMF). Using structural equation modeling, the researchers found increased temperatures to decrease AMF colonization. It is likely that as temperature and drought severity increase, soil moisture will become a stronger predictor of AMF colonization. Future shifts in the relationship between temperature, soil moisture, and AMF colonization could either exacerbate or mitigate the negative direct effect of temperature. As ecosystems in Mediterranean climates experience more intense droughts and heavier rains, decreases in AMF colonization could have substantial consequences for plant communities and ecosystem resiliency.
[embeddoc url=”https://blogs.uoregon.edu/phenology/files/2018/05/Wilson_mycorrhizae_HOPS-2j4xe02.pdf” download=”all” viewer=”google” ]
To Escape, Avoid, or Tolerate: Physiological Responses of Perennial Grasses to Experimental Climate Change
Maya Evelyn Goklany, 2012
The main objective of this study was to examine how Danthonia californica, Koeleria macrantha, and Agrostis capillaris leaf physiology responded to induced warming and precipitation. The study identified shifts in resource-use strategies in relation to carbon and water from wet to dry seasons. The differential effects of temperature and soil moisture on each species’ leaf physiology and fitness are also presented through structural modeling. The data also demonstrates that plant species within the same functional group harbor differential sensitivities to environmental factors and utilize different resource-use strategies to cope with drought.
[embeddoc url=”https://blogs.uoregon.edu/phenology/files/2018/05/Master-of-Science-Thesis-by-Maya-E-Goklany-2012-1-1pdn14g.pdf” download=”all” viewer=”google” ]
Drivers of Endophyte Communities in Pacific Northwest Prairies
Graham Bailes, 2017
This thesis examined the biotic and abiotic factors that influence endophyte communities within plants, using high-throughput sequencing across two native, cool-season bunchgrasses along a natural latitudinal gradient. Host traits and abiotic environment were found to be fairly unimportant, while spatial distance played the most important role. This research thereby highlights the importance of dispersal in shaping microbial, especially endophytic, communities
[embeddoc url=”https://blogs.uoregon.edu/phenology/files/2018/05/Graham_bailes_masters_thesis-1iku8iy.pdf” download=”all” viewer=”google” ]
The Performance of Four Native Perennial Forb Species Along a Climate Gradient in Pacific Northwest Prairies
Lauren Hendricks, 2016
This thesis examines the influence of local site factors versus regional climate on prairie plant phenology and vigor. Natural populations along a 700 km latitudinal gradient were analyzed by plant size, density, and reproductive timing. Overall, all species showed significant differences in plant size and reproduction between the studied populations, but, correlations between climate and site variables and plant size and reproduction were weak. Instead, the study shows that response was idiosyncratic by species.
[embeddoc url=”https://blogs.uoregon.edu/phenology/files/2018/05/Lauren-_Hendricks__masters_thesis_2016-2i7qas9.pdf” download=”all” viewer=”google” ]
The Herbaceous Landlord: Integrating the Effects of Symbiont Consortia Within a Single Host
Roo Vandergrift et al., 2015
This study focuses on the grass Agrostis capillaris and its root relationships with arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) across the changing climate gradient. It was hypothesized that competition between the symbionts for the host plant would result in colonization by the fungi that is most beneficial to the individual. When amount of colonized root length was measured and analyzed, the researchers found that there is a fitness cost to increased DSE colonization.
[embeddoc url=”https://blogs.uoregon.edu/phenology/files/2018/05/Vandegrift-et-al-Peer-J-2015-1vt2xci.pdf” download=”all” viewer=”google” ]
Pushing the Limit: Experimental Evidence of Climate Effects on Plant Range Distributions
Laurel Pfeifer-Meister et al., 2013
This study addresses the potential new ranges of 12 prairie species in response to changing climate. Accelerated temperature increase may influence species historical distribution or cause species extinction, making new ranges relevant to conservation biologists. Using the plots across Southern Oregon to Southern Washington, the authors found that warming affected species recruitment within their ranges. Once north of their current ranges, the plant species demonstrated differences in germination rates.
[embeddoc url=”https://blogs.uoregon.edu/phenology/files/2018/05/Pfeifer-Meister-et-al-2013-Pushing-the-limit-ro9c82.pdf” download=”all” viewer=”google” ]
Climate Change Alters Plant Biogeography in Mediterranean Prairies Along the West Coast, USA
Laurel Pfeifer-Meister et al., 2015
The multifactor climate of multiple sites within a Mediterranean climate zone was manipulated in order to study the impacts that climate change may have on the plant community composition and diversity in the coming decades. Cover, richness and diversity (plant community composition) were measured along with temperature and soil moisture for 3 years. Results indicate that the treatments caused northern plant communities to become more similar to southern communities. After two years, the cover of annual grasses and forbs increased and overall forb cover decreased at all sites. The added precipitation did not relieve drought stress and had little effect on plant community composition. Increased invasion of annuals and loss of forbs is predicted to be a result of increasing drought severity in Pacific Northwest prairies.
[embeddoc url=”https://blogs.uoregon.edu/phenology/files/2018/05/Pfeifer-Meister_et_al-2015-Global_Change_Biology-1-1le4kkn.pdf” download=”all” viewer=”google” ]