Plant Community Ecology

Although much is known about the composition and dynamics of the aboveground parts of grassland plant communities, very little is known about what goes on belowground. One potential project for this summer would be to measure how much plant biomass occurs in the shallow soils in desert grasslands at the Sevilleta. There are several experimental areas at the Sevilleta where studies of below ground production could be conducted. These include comparisons or burned and unburned areas, or grazed and ungrazed areas, or areas with and without added nitrogen fertilizer. Thus, a variety of interesting projects and comparisons are possible. (Mentor: Scott Collins)

Russian Olive, Elaegnus angustifolia,  propagate via seeds or clonal reproduction, and these propagules may be dispersed by water or animals, thereby making these plants prolific dispersers. E. angustifolia populations commonly exhibit invasiveness in riparian ecosystems. As a result, these olive habitats are overcrowded and have obstructed stream flow. In this project, the student will be responsible for leaf tissue sampling along the Rio Grande and genotyping using neutral genetic markers. The results will be used to determine population structure and dispersal patterns of E. angustifolia along portions of the river and its tributaries. This project is suitable for students interested in seed dispersal, riparian forest ecosystems, and plant population genetics. (Mentor: Brian Alfaro)

Plant community changes following prescribed fire at the Sevilleta National Wildlife Refuge. We are conducting experimental burning treatments in different seasons to determine the impact of fire seasonality on community and ecosystem processes. An experimental burn was conducted in November 2007 and additional fires are scheduled for March and June 2008. These plots are large enough for studying insect responses (pitfall traps), plant population and community studies, and ecosystem processes, such as soil C and N dynamics. (Mentor: Scott Collins)

Biological soil crusts are microbial communities that are found on the surface of almost all arid and semiarid ecosystems. They play ecologically important roles in nutrient and water cycling, which has been shown to benefit individual plant growth. In 2013, we initiated an experiment that investigates the role of soil crusts in structuring plant and arthropod communities and the impact of prolonged disturbance of soil crusts on these communities across a range of different biomes. Possible projects could include vegetation data collection and analysis; arthropod collection, identification, and analysis; analysis of chlorophyll content in soil crusts; or a combination of these projects. Students who have an interest in plant and soil microbial ecology or entomology will likely be a good fit for this project. (Mentor: Jenn Rudgers, Beth Haley, Anny Chung)

A study of below ground biomass production during the summer monsoon season. This would including digging sifting, drying and weighing root samples at the start and the end (sort of) of the monsoon season. Installing root in-growth bags (not donuts) etc. The question would be focused on which plant community type has the highest root abundance and dynamics in the top 20 CM of soil. ( Mentor: Scott Collins)

Edaphic characteristics are one of the major determinants of aboveground plant community composition. The Deep Well line intercept transect has long term vegetation data recorded, and this project would involve measuring edaphic properties such as soil texture, moisture, and/or C:N ratio, and correlate that to vegetation data (Mentors: Anny Chung).

One reason for invasiveness is phenotypic plasticity of functional and reproductive traits, which allows introduced plants to overcome initial pressures of bottleneck and founder effects. The student will investigate phenotypic plasticity in Sahara mustard (Brassica tournefortii Gouan), an invasive plant that has recently expanded in the roadsides, agricultural fields, and desert habitats of southwestern United States. The project involves greenhouse work, common garden field experiments, and molecular work. This project is suitable for students interested in invasive plant biology and evolutionary ecology.  (Mentor: Brian Alfaro)

We know very little about the larger scale patterns of vegetation and soils at the Sevilleta National Wildlife Refuge. The landscape offers interesting environmental gradients along the N and S ends of the Los Pinos Mountains. These gradients serve as an interesting environmental template for analysis of variation in plant and animal communities at the Sevilleta National Wildlife Refuge. (Mentor: Scott Collins)

Water is a very important driver in arid grassland ecosystems. During the growing season precipitation comes in distinct rainfall events that set the stage for plant production and growth. In general, rainfall is scattered in time and space such that soils often dry out after a particular storm event. What is the impact of continuous, frequent moisture on arid grassland plant communities? Does more water lead to more or fewer species of plants during the growing season? Several other hypotheses could be tested as well. (Mentor: Scott Collins)

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