REU Site for Ecosystems in Transition:

The Role of Research in Assessing Ecosystem Responses to a Changing Environment:

This program will not be held in 2008.

We hope to resume the program in 2009.

Independent Research Project:

In 2004 and 2005, the REU students initially assisted with existing research projects. This allowed them to learn sampling and analytical techniques that they could use in their own independent research projects.

During the first two weeks, the mentors for each REU student suggested one or two examples of “questions of interest” that could be investigated for their independent projects. The students also developed one or two research questions of their own. The students were not be restricted to working only at existing research sites when developing these ideas, as there were numerous ecosystems on University and public lands in the area that could provide suitable research locations.

Each student discussed possible ways of investigating all of the questions with their mentor(s) and then chose one as a topic of investigation for their independent research project. This selection was be made by the end of Week 3.

The student drafted a hypothesis and an experimental design appropriate for addressing the question. The mentors worked with the student to refine their design into a workable project that was be initiated by Week 4. The independent research project was the student’s dominant activity for most of the remainder of the summer.

Click here to view the Abstracts of the 2004 REU student research projects.

Independent Undergraduate Research Areas from 2005:

A. Importance of Coarse Woody Debris in Ecosystem Carbon Storage.

Mentor: Dr. Andrew J. Burton. Co-mentor: Dr. Kurt S. Pregitzer.

Coarse woody debris (CWD) can store large quantities of carbon in old-growth forests, but little is known about the potential rates of carbon accrual by this sink for today’s younger forests. Second-growth forests in the Lakes States have typically been managed in ways that limit the accrual of CWD, however the proportion of these forests on public lands that are actively managed for timber production is declining. Forests removed from active management will begin to accumulate CWD, but the relative rates of CWD production, decay and net accumulation for these forests is poorly understood. As a result, their potential to act as carbon sinks, mitigating a portion of atmospheric CO₂ increase, is unknown. The REU student will help assess CWD pools and their carbon and nitrogen contents in long-term research plots for which eighteen years of tree mortality data is available. They will then investigate an independent research question related to this topic. Possible research areas include comparing CWD biomass and carbon content among actively managed forests, unmanaged second-growth forests, and old growth forests of the region; examining rates of carbon loss (CWD respiration) of different CWD age or decay classes; or comparing CWD biomass and potential accumulation among different ecosystem types. A variety of study areas, including the largest remnant old-growth forests in the Midwest, are available near MTU for use in the REU project.

B. Using Stable Isotopes to Assess Ecosystem Change.

Mentor: Dr. Kurt S. Pregitzer. Co-mentors: Dr. Andrew J. Burton, Jennifer R. Eikenberry.

Air pollution is an important global change issue. Nitrogen (N) deposition from the atmosphere to forests has increased because of human-caused combustion of fossil fuels and other factors. The impacts of increased N-deposition on forest ecosystems are poorly understood, but the consequences to both terrestrial and aquatic ecosystems are potentially serious. Global change factors such as altered climate, N deposition, or elevated atmospheric CO₂ also can affect ecosystem composition and function by altering the cycling of carbon within forests. One way to examine carbon cycling in forests is through the use of the stable isotope ¹³C. Similarly, stable isotopes of nitrogen (¹⁵N) allow researchers to determine the rates at which N cycles through forest ecosystems. Since 1994, we have been studying the effects of chronic atmospheric N deposition on northern hardwood forests by adding additional NO₃ to research plots in the field. In the fall of 2003, ¹⁵N-labelled leaf litter was transplanted to forest locations used in this long-term study. We also have recently developed techniques to label plants in the field with ¹³C, allowing us to investigate the impacts of various global change factors on the allocation of carbon within plants and to the soil. The REU student will initially assist with ongoing projects to learn about the use of isotopes and mass spectroscopy in ecological research, and then will develop an independent project utilizing these techniques. The student will have a chance to learn how to use state-of-the-art ecological tools and work in a beautiful northern hardwood forest with trees up to 100 feet tall.

C. Relationship Between Moose Herbivory and Forage Quality.

Mentor: Dr. John A. Vucetich. Co-mentors: Dr. Rolf O. Peterson, Dr. Leah M. Vucetich.

Interactions between wolves and moose have been studied continuously on Isle Royale National Park since 1959. Adequate understanding of these dynamics requires better understanding of the interactions between moose and their forage species. Baslam fir is the primary winter forage for moose on Isle Royale. On the eastern quarter of Isle Royale fir is present in all size classes and shows only slight signs of being browsed. On the western half of Isle Royale fir is heavily suppressed by moose herbivory, and in the past 30 years no tree has escaped to grow taller than 1.5 meters. Moose densities in both regions are similar. The causes and consequences of these differences are poorly understood. To better understand the causes and consequences of these differences, the REU student will perform chemical analyses to investigate the association between browsing intensity and forage quality (e.g., C:N ratio and crude protein content). The REU student will be offered the education and opportunity to develop and test one of several plausible hypotheses regarding this association.

D. Impacts of Exotic Species on Forest Communities.

Mentor: Dr. Andrew J. Storer.

Exotic species often have profound effects on native ecosystems. Alteration of dominant forest overstory species composition is perhaps the best understood and most noticeable of these effects. American chestnut has been essentially removed as a dominant overstory tree in eastern north American forests as a result of chestnut blight, and populations of elms have been severely impacted by Dutch elm disease. In Michigan’s Upper Peninsula, beech bark disease is currently altering the community structure of beech forests and causing significant mortality. Other exotic species, such as the European snout beetle, which feeds on leaves and roots of hardwood trees, have less well understood impacts. The REU student will have the opportunity to work on exotic species issues in forests and interact with personnel in the Center for Exotic Species (www.forest.mtu.edu/ces) at MTU. Through this interaction, the student will develop a novel research project that involves exotic insects, pathogens or weeds. Possible project areas include testing volatiles produced in response to the sudden oak death pathogen for attractiveness to bark beetles; relating health of ash trees to abiotic variables in recreational areas in order to understand the potential for damage by the emerald ash borer; exotic weed invasion of forests under differing management regimes; and sublethal effects of European snout beetles on sugar maple seedlings.

E. Restoring the Yellow Birch Component of Northern Forests.

Mentor: Dr. Christopher R. Webster. Co-mentor: Dr. Linda M. Nagel.

Traditional single-tree selection management of northern hardwoods has provided reliable outputs of high-quality wood products, and maintained contiguous forest cover in managed stands. However, the long-term consequences of this management strategy include lower tree species diversity, development of monotypic stands of shade-tolerant hardwoods (e.g. sugar maple), and the loss of ecologically significant species (e.g. yellow birch) that are sensitive to shade. The impacts of these changes in forest composition on other organisms (insects, birds, and herbaceous plants) are not well known, though preliminary research has suggested that species in decline, like the mid-tolerant yellow birch, may have a disproportionately large influence on the diversity of neotropical migrant songbirds. The REU student will assist with a study examining the impacts of group selection on yellow birch establishment and biodiversity. In addition, the student will resample an established strip clearcutting trial for regenerating yellow birch.

F. Effects of Exotic Salmonids and Habitat Conditions on Native Brook Trout Populations and their Rehabilitation.

Mentor: Dr. Casey Huckins

Brook trout (Salvelinus fontinalis) are core native members of the Great Lakes ecosystem and a species of great importance to the heritage of Lake Superior in particular. Lake-dwelling populations of brook trout, locally referred to as coasters, were once abundant in the near shore waters of the Upper Great Lakes where they supported a destination fishery. Over harvest along with possibly interacting effects of habitat degradation during the 1800’s lead to the extirpation of most populations of coaster brook trout. Only a few remnant populations are known to persist today, and only one of these viable populations is known to survive along the south shore of Lake Superior. Today, the rehabilitation of coasters is a state, federal, tribal and international goal. The likelihood of successful and long-term rehabilitation of brook trout will in part depend on understanding the specific biotic and abiotic factors influencing individuals and populations. We currently do not understand the extent to which current habitat limitation, driven by land use and negative interspecific effects of introduced and naturalized trout and pacific salmon populations, may limit current brook trout population performance and future brook trout rehabilitation. Our ongoing research programs examine the current distribution, life history, population structure and habitat use of brook trout in Lake Superior tributaries and the possible effects of habitat alteration and interspecific interactions with introduced trout and salmon. The REU student will work with us on these projects and develop a pertinent independent project within this system.

G. Global Change Effects on the Structure and Function of Mycorrhizal Fungal Communities.

Mentor: Dr. Erik Lilleskov. Co-mentor: Dr. Kurt S. Pregitzer or Dr. Andrew Storer.

Mycorrhizal fungi form symbiotic associations with plant roots, exchanging soil resources for plant sugars. Mycorrhizal fungal communities are diverse, and are sensitive to global change factors such as atmospheric N deposition, elevated CO₂ and O₃ concentrations and invasive soil organisms. The REU student would assist with field work at the Aspen FACE experiment on the effects of elevated CO₂ and O₃ on forest ecosystems, or the Michigan Gradient Study examining the effect of N deposition and fertilization on ecosystem function in sugar maple dominated stands, or on a study of the ecosystem effects of invasive soil organisms. These projects involve field and lab work investigating mycorrhizal fungal community structure and function, and a variety of opportunities exist for independent research. The student will have the opportunity to learn and apply cutting-edge molecular DNA methods for the characterization of fungal communities. Possible REU projects include: examining the effects of N fertilization, CO₂ and O₃, or earthworms on mycorrhizal fungal communities; or other projects developed in consultation between student and mentor.

H. Distribution of Invasive Plant Species Along Multi-Use Recreational Trails.

Mentor: Dr. Linda M. Nagel. Co-mentor: Dr. Christopher R. Webster.

Invasive plant species have become an increasing concern for land managers because of their competitiveness and resilience. Invasives often out-compete native vegetation, changing the species diversity of an area. Disturbance and invasion of exotic plant species seem to go hand-in-hand. The presence and spread of invasives has often gone undetected, leading to future management concerns. This project will involve an introductory characterization of invasive plant species in two multi-use recreational trail systems: the Michigan Tech trail network adjacent to campus, and Canyon Falls, adjacent to the School’s Ford Forestry Center. The REU student will conduct plant surveys along roads, skid trails, and hiking trails. This data will be used to characterize the distribution of species, and will indicate spread patterns as related to disturbance and intensity of human foot traffic. Depending on the number of species identified, the student will focus on a suite of invasive plant species of special concern. A GIS system will also be used to map general locations of species with regard to parking lots, trailheads, and trails. The map will provide the basis for future monitoring and identification of species that may require management action. In addition to plant surveys, light measurements will be taken along transects from the center of trails into the forest to elucidate possible causal mechanisms, and to quantify edge effects within these forested recreational areas.

I. Soil Carbon Formation in a Changing Environment.

Mentor: Dr. Christian Giardina.

Forested ecosystems account for 60% of terrestrial carbon (C) storage, and concern over the potential for elevated atmospheric CO₂ to cause significant changes in global climate has created interest in enhancing the capacity of forests to store C in biomass and soils. The chemical composition of plant litter (dead leaves, branches and roots) is one factor that regulates soil C formation. Altering the quantity of decay resistant lignin in trees may be a potential method for increasing forest C storage in both biomass and soils. We are cultivating aspen trees with different levels of lignin in the greenhouse at Michigan Tech and will study their decomposing leaves and roots to determine if changes in plant lignin content can alter soil C formation and storage. The REU student will assist with this experiment and then develop a complementary project that explores the role of litter chemical composition on soil C formation. This could include a lab examination of how nutrient availability affects litter decomposition, a field decomposition experiment with different litter types or litter from different species, or a project designed to answer questions of particular interest to the student. The numerous natural and experimental forests in the area, greenhouse facility, stable isotope lab, and other analytical instruments available, provide unlimited potential for an REU student to explore soil C formation.

J. Genetic and environmental regulation of leaf phenolics in Populus.

Mentor: Dr. Chung-Jui Tsai. Co-mentor: Dr. Scott Harding.

Leaf phenolics, including phenolic glycosides (PGs) and condensed tannins (CTs) are the predominant secondary metabolites in Populus. They contribute to the fitness of these species by acting as UV-B protectants and by deterring generalist insect defoliators. In nature, their levels vary among closely related species and clones, during development, and depending on the environment (e.g., soil fertility, light, drought etc). The REU student will screen an aspen seed population for variable foliar PG-CT phenotypes and apply DNA markers to determine their genetic kinship. Individuals with contrasting PG-CT phenotypes will be used for gene expression study to examine the transcript levels of key phenolic metabolism genes. The student will also develop an independent project to investigate effects of environmental stresses on leaf chemistry, gene expression and growth of vegetatively propagated Populus clones. The student will have access to the greenhouse facility and the molecular, genomics, and biochemistry laboratories at the Biotechnology Research Center.