Ecological Research Projects

Diversity of soil microbes and the function of beech-maple forests

The natural areas of The Holden Arboretum contain some of the finest examples of mature, intact beech-maple forest in Ohio. Holden is conducting research into the effects of soil physical and chemical properties on the diversity and function of soil microbes in these forests. In particular, we are interested in soil fungi that colonize plant roots (mycorrhizae) and how this symbiotic association controls the structure and function of these forests and how they respond to environmental variability and change. Holden scientists are using molecular techniques that extract and amplify DNA from environmental samples to determine the diversity and relative abundance of these important soil fungi, as well as measuring microbial processes using biogeochemical techniques.

 

handful of soil with tree roots
fungi on tree root
fungal sporocarp in forest
Tree roots in soil
Mycorrhizal fungi on roots
Fungal fruiting body in the forest

 

Winter ecology and altered precipitation dynamics

Most studies of forest ecosystems and soil microbial communities at northern latitudes ignore functional processes that occur during cold months or under snow. Recent work by Holden scientists and others has suggested that these processes may be more important that previously thought and can represent a significant portion of annual carbon and nutrient cycling in many ecosystems. Moreover, altered precipitation and temperature patterns related to climate change might influence the magnitude and importance of winter processes in the Great Lakes region. Holden scientists are working to understand how forests and soils in Northeast Ohio function during our extended periods of cold temperatures and snow cover.

 

snow removal experiment

collecting litterbags in forest
Manipulating soil temperature and soil freezing
Estimating leaf decomposition under snow

 

Acidic precipitation and forest health

Acidic precipitation resulting from burning fossil fuel is a chronic problem in areas near population centers or concentrations of industrial activity. The northeastern United States is one area that receives particularly high levels of acid precipitation. The resulting ecosystem acidification can impact plants, soils and water. In hardwood forests, such as those common in Northeast Ohio, there is concern that long-term acidification of forests and can decrease the availably of the essential nutrients phosphorus and calcium in soil, which could result in poor forest health and forest decline. Holden scientists, along with Professor J. L. DeForest at Ohio University, received a grant from the National Science Foundation (www.nsf.gov) to look at how forests and soils respond to changes in acidity and soil phosphorus availability. They are manipulating soil pH and fertility in a long-term study of Ohio forests using crushed limestone (lime) and phosphorus fertilizer and watching how plants and soil microbes respond.

 

     
super sacks of lime
Holden research crew
Applying lime with spreader
Bags of lime that were spread on forest plots
Transporting lime into the forest
Applying lime by hand

 

Production and emission of greenhouse gases from soil

 

 

 

 

Soils are an important source of atmospheric greenhouse gases such as carbon dioxide, methane and nitrous oxide. Because these gases are biologically produced, the processes controlling their production and emission to the atmosphere are sensitive to environmental change. It is uncertain how these soil processes will respond to current and future changes in climate and soil chemistry, and the potential exists for a variety of feedback mechanisms. Holden scientists are sudying the microbial processes that control the dynamics of these gases in forest and wetland ecosystems and developing new techniques to study greenhouse gas biogeochemistry.

 
 
Measuring winter soil respiration
 

 

Jenning's Woods complex ecosystem study

Ecologists in the field collecting leaf litter in Jenning's Woods

 

 

 

 

Despite the fact that is a contral tenet of ecolgy, there is still much to learn about rules governing the diversity, assembly, and distribution of organisms and those rules are relatedt to differences in the environment. Holden scientists, along with collaborators Christopher Blackwood and Mark Kershner at Kent State University are using hardwood forest to test ecological theories relating to the spatial and temporal distributions of diverse biological organisms. Specifically, they are working in a spatially complex forest ecosystem (Jenning's Woods) in Northeast Ohio and using manipulative experiments and rigorous statistical modeling to test theories related to biogeographical and niche-related patterns.

Collecting leaf litter at Jenning's Woods
 

 

Horticultural Research Projects

Please browse to the David G. Leach Research Station web site for horticultural research project information.