ESA to feature wide range of UW-Madison presentations
The Ecological Society of America will hold its 93rd annual meeting on Aug. 3-8, 2008, in Milwaukee, Wis. The society was founded in 1915 to promote the practice and awareness of ecological science.
This year’s meeting will highlight the interdisciplinary nature of ecology and linking research with education. A wide range of UW–Madison research will be presented each day at the meeting.
Presentations on Friday, Aug. 8
Homeowners hoping to do their part for urban water quality have made rain gardens – small garden plots for capturing stormwater – one of the fastest-growing features of the home landscape. But as their popularity has risen, so have opinions about the plants they should contain. Some insist that prairie species are needed to penetrate compacted soil and allow stormwater to permeate the ground. Others claim that typical urban plants, such as turfgrasses and shrubs, work just as well.
As a first foray into this issue, soil scientists Nick Balster and Marie Johnston examined the soils beneath a dozen prairie gardens ranging from one to 15 years-old at private homes in Madison, Wisconsin, and compared them with those in adjacent stretches of manicured lawn. Soil parameters, such as density and compaction, differed little between the prairie garden and turfgrass plots, the pair found. Instead, the age of the residence was the biggest factor, with soils at homes built before the 1970s showing less compaction than those at younger sites.
Prairie garden soils did, however, have higher levels of organic matter and soil aggregation – changes that, over time, may lead to less dense soil and higher infiltration rates, says Balster.
Presentations on Thursday, Aug. 7
There is growing interest in using the uncultivated portions of farms for biodiversity conservation purposes. The Wisconsin Healthy Grown Potato eco-label provides an economic incentive for growers to implement conservation and restoration plans on their non-crop lands.
Environmental studies professor Paul Zedler and UW-Extension scientist Deana Knuteson are leading efforts to assess current levels of biodiversity in non-croplands adjacent to potato fields in central Wisconsin. Participating farms – currently around a dozen – conduct one or more management practices chosen to enhance the conservation value of non-crop lands.
Current projects being presented at the ESA meeting include analyses of the diversity and abundance of native plants, birds, and beneficial insects. Early results show that even without ecological management these farms contain a significant proportion of native biodiversity and highlight the conservation value of non-field habitats next to cultivated potato fields.
Not only does Wisconsin have more dams than any other state, it’s removing dams more quickly than nearly any other state as well. By restoring natural flows to streams and rivers dam removal offers many benefits to fish communities. But once a reservoir is drained, freshly exposed sediments can become hot beds of invasive plants. Little is known about the factors that control plant communities in these basins or whether they offer favorable sites for restoration.
As part of a project to characterize the soils in a recently drained basin in southwestern Wisconsin, soil scientists Sam Eldred, Ana Wells and Nick Balster spread the seeds of prairie plants at densities ranging from very high to none. Three years of monitoring has now revealed that despite the altered state of the sediments after 60 years of impoundment, prairie species seeded at the highest densities seem to be holding their own against invasive plants, says Balster. However, the amount of seed this takes – 1,000 seeds per roughly 10 square-feet – would be prohibitively expensive for most landowners.
Balster is now interested to see if, over time, prairie growth in plots that were seeded at mid-range or even low densities might also prove successful.
Presentations on Wednesday, Aug. 6
Lakeshores offer prime real estate for residences and recreation, but this development comes at an ecological price. Two studies to be presented at the ESA meeting offer new insights into determining how lakeshore development impacts sport fish populations.
Van Butsic, David Lewis, and Volker Radeloff will present an economic model to predict housing density around lakes based on zoning policies and other development constraints. They report that decreasing the minimum frontage zoning will increase lakefront housing density. Since bluegills are known to be adversely affected by increasing development, they predict that reducing frontage minimums would substantially compromise bluegill growth.
Jereme Gaeta, Stephen Carpenter, and colleagues have found that growth rates of most size classes of largemouth bass, a popular sport fish, are also negatively impacted by development. In 16 northern Wisconsin lakes, they found that larger fish grow more slowly in lakes surrounded by more extensive building than in less developed lakes. The effect is most pronounced on the largest bass, those over about 10 inches, which show a strong decline in growth rate with increasing numbers of neighboring homes.
Presentations on Tuesday, Aug. 5
Climate models generally predict an increase in climate variability and extremes due to the enhanced greenhouse effect. Michael Notaro, a scientist in the UW–Madison Center for Climatic Research, has applied a dynamic global vegetation model to determine how year-to-year climate fluctuations will affect vegetation types and patterns and fire risk.
He has found that interannual climate variability reduces net global vegetation cover, particularly in semi-arid regions such as the southwest U.S. At the same time, the model reveals that year-to-year variability in precipitation supports greater frequency and intensity of wildfires.
High interannual climate variability can change vegetation patterns, favoring the expansion of grass cover at the expense of tree cover and, within forested areas, the expansion of deciduous forest at the expense of evergreen forests. These results offer insight into future global and regional ecosystem distributions and boundaries.
Native brook trout in streams on Wisconsin’s Bayfield Peninsula have struggled for decades, mainly due to springtime floods of snowmelt that blanket their gravel spawning beds with sand and clay. Logging and denuded stream banks are often to blame when streams experience intense runoff. Yet, after being heavily logged in the late 1800s, this area along Lake Superior’s south shore is mostly reforested. So, why is the problem continuing?
Drainage from farm fields and roads are partly to blame, but forest ecologists Jordan Muss and David Mladenoff think another answer may lie in the treetops. Though historically dominated by spruce, pine and other evergreens, the peninsula’s forests today are mostly composed of deciduous trees. So, the pair hypothesized, when evergreens were abundant, perhaps their leafed branches in winter held more snow, allowing it to evaporate from the canopy rather than accumulate below. Two winters of data collection under a variety of the peninsula’s forest types now support this: Snow pack drops by as much as 55 percent as canopy density increases.
The findings suggest that managing forests for more evergreen species could help curb runoff. The scientists will explore this possibility next through a modeling study.
In 1992, forest and wildlife ecology professor David Mladenoff began identifying and mapping Wisconsin’s most preferred wolf habitat, both to assist in the management of existing packs and predict where new ones might establish. Though he included a wide variety of landscape characteristics in his model, including the presence of forests and wetlands, and the densities of streams and deer, what wolves seemed to prefer above all else were areas with fewer roads. Now, with more than 500 wolves roaming the state and much of that top habitat occupied, does this prediction still hold?
Yes, says Mladenoff, with some nuances. While roads still play a part in his new model, the most critical factor is agriculture, whose presence appears to have a strong negative effect on wolves’ ability to establish. Wolves are least successful in places with many roads and farms because these landscape features represent contact and conflict with humans, he says.
While this suggests that wolves likely won’t colonize central and southern Wisconsin heavily in the future, he cautions that habitat preferences could shift again now that wolves no longer enjoy protection as endangered species in the state.
Ecological changes are complex and occur over large spans of space and time, making the specific causes and effects of change difficult to track. UW–Madison botany professor Don Waller and his research group are studying ecological changes in Wisconsin over time by comparing modern data with a rare and valuable historical resource – a detailed dataset of plant communities in the state compiled by John Curtis in the 1950s.
Four presentations at the ESA meeting will describe some of the group’s approaches to understanding what factors drive ecological change and how such changes are affecting Wisconsin’s environment today. Their studies show that forest habitat fragmentation, invasive plant species, and deer have each profoundly impacted Wisconsin’s forests over the past 50 years. In many areas, native species have declined, invasive plants have gained a foothold, and overall plant diversity has dropped as previously diverse areas become more and more similar. An understanding of the factors underlying ecological change may help guide efforts to identify vulnerable habitats and management strategies to protect the state’s natural resources.
Presentations on Monday, Aug. 4
A new book, titled “The Vanishing Present: Wisconsin’s Changing Lands, Waters, and Wildlife,” examines how human pressures – urbanization, population growth, and land use changes – are reshaping the state’s ecology and environment. Edited by UW–Madison botany and environmental studies professor Don Waller and Wright State University biology professor Thomas Rooney, the book brings together viewpoints of dozens of scientists, natural resource managers, and policy experts to offer insight into Wisconsin’s ecological past, present, and future. The book will be available at the meeting.