RESEARCH
Research in the lab investigates the abiotic and biotic factors (and their interactions) that affect plant species dynamics and ecosystem function.
We employ a variety of research methods (e.g. experiments, long term observational data sets, statistical models) to answer questions pertaining to both fundamental and applied science in plant communities.
Student research is an important component of the lab. Interested students are encouraged to contact Dr. Byrne about research opportunities and see the people section of this website for current student projects.
We employ a variety of research methods (e.g. experiments, long term observational data sets, statistical models) to answer questions pertaining to both fundamental and applied science in plant communities.
Student research is an important component of the lab. Interested students are encouraged to contact Dr. Byrne about research opportunities and see the people section of this website for current student projects.
Restoring coastal dunes after yellow bush lupine invasion
The coastal dunes of Humboldt County are home to some of the most intact dune ecosystems in North America. Yet these local ecosystems are challenging to manage due to exotic species, despite major restoration efforts beginning in the 1980’s. One of the more important exotic species in the region is yellow bush lupine, an exotic nitrogen-fixing legume, which alters the chemical structure of the dunes by enriching the soils with nitrogen.
Previous studies have demonstrated that yellow bush lupine negatively affects the biological community long after plants are physically removed due to the impact on soil chemical processes. Even after removal, the nitrogen-rich patches in areas previously occupied by yellow bush lupine facilitate the invasion of exotic annual weeds into the plant community, at the detriment of the native “dune mat” vegetation. Despite the challenges of this invader, some studies have found success in immobilizing soil nitrogen by adding carbon sources to the soil. The goal of this new project, in collaboration with the US Fish and Wildlife Service, is to test the efficacy of carbon addition in reducing plant available nitrogen, thus decreasing the probability of future invasion by exotic grasses even after the yellow bush lupine has been removed. In spring 2019, a California Conservation Corps crew removed yellow bush lupine from a newly acquired parcel at Lanphere Dunes. We added carbon in the form of pulverized rice straw to fifteen 1.0 x 1.0 m plots, and are tracking changes in plant available nitrogen and species composition over time, compared to fifteen "control" plots where the lupine was removed, but no carbon was added.
The coastal dunes of Humboldt County are home to some of the most intact dune ecosystems in North America. Yet these local ecosystems are challenging to manage due to exotic species, despite major restoration efforts beginning in the 1980’s. One of the more important exotic species in the region is yellow bush lupine, an exotic nitrogen-fixing legume, which alters the chemical structure of the dunes by enriching the soils with nitrogen.
Previous studies have demonstrated that yellow bush lupine negatively affects the biological community long after plants are physically removed due to the impact on soil chemical processes. Even after removal, the nitrogen-rich patches in areas previously occupied by yellow bush lupine facilitate the invasion of exotic annual weeds into the plant community, at the detriment of the native “dune mat” vegetation. Despite the challenges of this invader, some studies have found success in immobilizing soil nitrogen by adding carbon sources to the soil. The goal of this new project, in collaboration with the US Fish and Wildlife Service, is to test the efficacy of carbon addition in reducing plant available nitrogen, thus decreasing the probability of future invasion by exotic grasses even after the yellow bush lupine has been removed. In spring 2019, a California Conservation Corps crew removed yellow bush lupine from a newly acquired parcel at Lanphere Dunes. We added carbon in the form of pulverized rice straw to fifteen 1.0 x 1.0 m plots, and are tracking changes in plant available nitrogen and species composition over time, compared to fifteen "control" plots where the lupine was removed, but no carbon was added.
Conservation of Applegate's milkvetch
Applegate's milkvetch (Astragalus applegatei) is a critically endangered plant species that is a narrow endemic of the Lower Klamath Basin in Southern Oregon, within the city of Klamath Falls. Once thought to be extinct, it is now know to exist at only a few sites within the Lower Klamath Basin.
Previous research has helped to identify the germination requirements and mycorrhizal and rhizobial associations of the species. More recently, the United States Fish and Wildlife Service (USFWS) has worked with a local nursery to improve propagation techniques. In 2012, 2013, and 2014, volunteers and biologists from the USFWS augmented one of the protected populations by out-planting hundreds of A. applegatei seedlings that have been propagated in the greenhouse. To date, no thorough demographic monitoring program has established the success of this out-planting program. We conducted thorough demographic monitoring of all out-planted individuals at this site over six years, tracking seedling survival, reproduction, and recruitment. In June, 2015, an additional study was funded by the USFWS to begin demographic monitoring of native, wild plants in four populations across the Upper Klamath Basin. Work on this project began in summer 2016, and will last for five years. In both projects, we will use the data to develop stage-based population models for the species.
Three OIT undergraduates completed a study to learn more about the reproductive biology of Applegate's milkvetch (Byrne et al., in prep).
With Catalina Cuellar-Gempeler (HSU Biology) we are initiating a new project to better understand the role of the microbial community in the success of Applegate's milkvetch population growth.
Each of these projects will assist Federal, State, and Local agencies in planning future conservation efforts, and are vital for the recovery of this imperiled species.
Applegate's milkvetch (Astragalus applegatei) is a critically endangered plant species that is a narrow endemic of the Lower Klamath Basin in Southern Oregon, within the city of Klamath Falls. Once thought to be extinct, it is now know to exist at only a few sites within the Lower Klamath Basin.
Previous research has helped to identify the germination requirements and mycorrhizal and rhizobial associations of the species. More recently, the United States Fish and Wildlife Service (USFWS) has worked with a local nursery to improve propagation techniques. In 2012, 2013, and 2014, volunteers and biologists from the USFWS augmented one of the protected populations by out-planting hundreds of A. applegatei seedlings that have been propagated in the greenhouse. To date, no thorough demographic monitoring program has established the success of this out-planting program. We conducted thorough demographic monitoring of all out-planted individuals at this site over six years, tracking seedling survival, reproduction, and recruitment. In June, 2015, an additional study was funded by the USFWS to begin demographic monitoring of native, wild plants in four populations across the Upper Klamath Basin. Work on this project began in summer 2016, and will last for five years. In both projects, we will use the data to develop stage-based population models for the species.
Three OIT undergraduates completed a study to learn more about the reproductive biology of Applegate's milkvetch (Byrne et al., in prep).
With Catalina Cuellar-Gempeler (HSU Biology) we are initiating a new project to better understand the role of the microbial community in the success of Applegate's milkvetch population growth.
Each of these projects will assist Federal, State, and Local agencies in planning future conservation efforts, and are vital for the recovery of this imperiled species.
Ecosystem response to global environmental change
With co-Principal Investigator Dr. Kristen Kaczynski (California State University, Chico) we are investigating the impacts of intense, long-term drought on the western Great Basin sagebrush ecosystem. The experiment is part of a large network of concurrent drought experiments, called the International Drought Experiment. This project aims to help inform future management decisions for the Bureau of Land Management.
Dr. Byrne's dissertation research examined the effects of precipitation changes on plant species composition and community structure in native grassland communities in the Great Plains of North America. She used a field experiment to manipulate rainfall in three treatments- control, water addition, and drought - and measured changes in species composition (Byrne et al. 2017) and aboveground (ANPP) and belowground (BNPP) net primary production (Byrne et al. 2013) in each treatment over 3-4 years. This research improved our understanding of ecosystem dynamics under climate change, especially BNPP dynamics, which are infrequently studied and not well understood.
In the same research framework, Dr. Peter Adler (Utah State University) and Dr. Byrne reversed the drought and water addition treatments at the more mesic mixed grass prairie site in Hays, KS, during the fourth treatment year to quantify the magnitude of community response to the switch between extreme above and below average precipitation years (Adler, Byrne, and Leiker, 2013).
With co-Principal Investigator Dr. Kristen Kaczynski (California State University, Chico) we are investigating the impacts of intense, long-term drought on the western Great Basin sagebrush ecosystem. The experiment is part of a large network of concurrent drought experiments, called the International Drought Experiment. This project aims to help inform future management decisions for the Bureau of Land Management.
Dr. Byrne's dissertation research examined the effects of precipitation changes on plant species composition and community structure in native grassland communities in the Great Plains of North America. She used a field experiment to manipulate rainfall in three treatments- control, water addition, and drought - and measured changes in species composition (Byrne et al. 2017) and aboveground (ANPP) and belowground (BNPP) net primary production (Byrne et al. 2013) in each treatment over 3-4 years. This research improved our understanding of ecosystem dynamics under climate change, especially BNPP dynamics, which are infrequently studied and not well understood.
In the same research framework, Dr. Peter Adler (Utah State University) and Dr. Byrne reversed the drought and water addition treatments at the more mesic mixed grass prairie site in Hays, KS, during the fourth treatment year to quantify the magnitude of community response to the switch between extreme above and below average precipitation years (Adler, Byrne, and Leiker, 2013).
Influence of precipitation seasonality and quantity on ecosystem net primary production
Understanding drivers of aboveground net primary production (ANPP) has long been a goal of ecology. Decades of investigation have shown total annual precipitation to be an important determinant of ANPP within and across ecosystems. Recently a few studies at individual sites have shown precipitation during specific seasons of the year can more effectively predict ANPP. In this project we determined whether seasonal or total precipitation better predicted ANPP across a range of terrestrial ecosystems, from deserts to forests, using long-term data from 36 plant communities. We found that examining seasonal precipitation can significantly improve ANPP predictions across a broad range of ecosystems and plant types, with implications for understanding current and future ANPP variation (Robinson et al., 2013).
Understanding drivers of aboveground net primary production (ANPP) has long been a goal of ecology. Decades of investigation have shown total annual precipitation to be an important determinant of ANPP within and across ecosystems. Recently a few studies at individual sites have shown precipitation during specific seasons of the year can more effectively predict ANPP. In this project we determined whether seasonal or total precipitation better predicted ANPP across a range of terrestrial ecosystems, from deserts to forests, using long-term data from 36 plant communities. We found that examining seasonal precipitation can significantly improve ANPP predictions across a broad range of ecosystems and plant types, with implications for understanding current and future ANPP variation (Robinson et al., 2013).