The Effect of Jumping Worm (Amynthas spp.) on Above-ground Woodland Vegetation
Laushman and Hotchkiss are researching the effect of the newly discovered Asian jumping worm on the overall health of vegetation in Wingra Woods and Gallistel Woods. Laushman has set up plots to survey the diversity of herbaceous and woody plants in areas invaded by the worm and uninvaded areas to assess the differences in the plant communities. Her work will add to our knowledge of how jumping worms affect native Wisconsin ecosystems and will help us better understand restoration challenges at the Arboretum in light of this new invasion.
Effects of European Buckthorn (Rhamnus cathartica) on Small Mammal Post-dispersal Seed Predation
Spatial patterns of animal foraging have important consequences for understanding the dynamics of animal movement, the strength of plant-animal interactions, and the ecology of disease. Although invasive plants, such as buckthorn (Rhamnus cathartica), can modify the abundance and activity level of small mammals by providing a low-risk environment for them to forage, it is unknown whether this produces significant changes in space use by small mammals. Guiden and Orrock are testing the influence of invasive R. cathartica on spatial patterns of small mammal foraging by investigating the spatial distribution of small mammal seed predation on red oak (Quercus rubra).
Intervention Strategies for Deer Ticks and Tick-borne Pathogens in Wisconsin and the Arboretum
Spurred by the discovery of a single larval deer tick in 2010, UW–Madison researchers have worked diligently with Arboretum staff to assess the growing threat of a newly established deer tick population. Since 2010, surveys have not only indicated an increasing number of ticks throughout the Arboretum property, but have also shown growing incidences of tick-borne pathogens such as Lyme disease that threaten community health. To quell these growing trends, members of the UW–Madison Medical Entomology Laboratory have begun exploring host-targeted interventions designed to reduce the tick population and reduce the infection rate of reservoir hosts that perpetuate the pathogen’s life cycle. Researchers continue to monitor the status of tick infestation in the Arboretum and possible tools to protect neighbors and outdoor enthusiasts alike.
Interaction Between the Jumping Worm (Amynthas spp.) and European Buckthorn (Rhamnus cathartica)
This project asks how a recently discovered invasive species, the Asian jumping worm, might interact with European buckthorn. European earthworms – on which much of the current understanding of invasive earthworm impacts is based – aid buckthorn spread via alterations to the forest floor that enhance buckthorn germination. European earthworms also prefer nutrient-rich buckthorn litter to that of native species, facilitating earthworm invasion in buckthorn-dominated areas. Recent studies suggest jumping worms may outcompete their European counterparts and have greater impacts on litter reduction. Yet no research exists on Amynthas spp. litter preferences or potential impacts of the recent invader on buckthorn germination and establishment. Interactions between these species could have substantial consequences for ecosystem services in areas where they co-occur. The presence of both species and available facilities at the UW–Madison Arboretum provide a unique opportunity to study this species interaction and its potential consequences within the Madison area, with implications for other Midwestern landscapes.
Effect of Climate Change on Subnivium Habitat
Many organisms in the Great Lakes Region survive extreme winter conditions by taking refuge in the subnivium, which maintains temperatures around 0 degrees C throughout the winter. The snow pack forms an insulative layer that traps warm air escaping from the soil. However, as the snow pack decreases in depth and becomes denser, it becomes less insulative, and as a result the subnivium becomes colder and less thermally stable. Warming winter conditions are likely to cause a decrease in snow depth and snow duration across North America, and we predict that the result will be a subnivium that is colder and less thermally stable.
To test this hypothesis researchers have built 27 micro-greenhouses which are distributed throughout the Great Lakes Region and across different habitat types. Three of these greenhouses are at the Arboretum. The greenhouses have automated roofs that open during precipitation events, allowing the same amount of snow to accumulate both inside and outside of the greenhouse. Once it has stopped snowing, the greenhouse heats to a set temperature above ambient, allowing researchers to simulate the effects of future warming winters on snow pack characteristics and subnivium temperature.
Uncovering the Secret Winter Life of the Jumping Worm (Amynthas spp.): Cocoon Abundance and Temperature Tolerance
Johnston is investigating questions about the abundance and hatching constraints of Asian jumping worm cocoons. There has been very little research done on cocoon biology, but due to their small size and difficulty of detection, it’s possible, or even likely, that they can be a major factor in how this invasive species is spread. Johnston and others are researching the correlation between adult jumping worm abundance and the abundance of cocoons, if freezing temperatures are needed to induce cocoon hatching, and if high temperatures can affect viability of cocoons. Results from this research will help agencies and others who are working to mitigate the spread of this invasive species.
Long- and Short-term Vegetation Dynamics at Greene Prairie
Brad Herrick, Arboretum
Prairie plants at Greene Prairie have been monitored since the 1950s, resulting in a dataset of plant species richness over 60+ years. This data will be analyzed to investigate trends in native and invasive plant diversity. More recently, we have collected plant species richness and cover data in areas of the prairie before and after invasive woody shrubs and trees were removed to determine how this common restoration technique affects plant diversity.
Persistence of Native Species Planted in a Stormwater Retention Pond
Native wetland species are often planted in and around stormwater treatment facilities to create or restore habitat in these artificial systems. However, few plantings are monitored thereafter. In 2009, a 1.6 ha. (4 ac.) retention pond was constructed at the Arboretum to treat an average of forty-four million gallons of stormwater annually. After pond construction, eight native emergent macrophyte species were planted in the shallow water zone. Shortly after planting, invasive cattails move in and competed with the planted natives. Species richness in plots was documented one year after planting in 2010, and again in 2016 to determine what impact, if any, the cattails have had on the native species.
Predicting Dragonfly Occupancy at Stormwater Retention Ponds in Southern Wisconsin
Andy Cassini, Department of Zoology
Robert Bohanan, North Temperate Lakes Long-term Ecological Research, WISCIENCE
Brad Herrick, Arboretum
Stormwater retention ponds are common best management practices (BMPs) for improving the quality of runoff and protecting downstream lakes and wetlands. However, few studies have looked at these ponds for their value as wildlife habitat. In 2016, more than 50 stormwater retention ponds in southern Wisconsin, including ten at the Arboretum, were surveyed for dragonfly species. In addition, numerous habitat variables such as vegetation cover type(s), amount of buffer, water clarity, pond size, etc., were collected. Occupancy models will be used to predict which habitat variables are most important for certain species of dragonflies and their overall diversity in and around these artificial ponds.
Influence of Sediment on Dissolved Phosphorus Levels in Stormwater Runoff though Curtis Prairie
Elizabeth Buschert, Biological Systems Engineering, Arboretum
Soil and sediments can be a source or sink for phosphorus in aquatic systems, depending on present levels of phosphorus and phosphorus-absorbing constituents. This project will analyze sediments in Curtis Pond and at 5 to 6 downstream points of the outlet along the effluent path, to try to determine the influence of sediment on dissolved phosphorus levels in stormwater runoff. Buschert will also analyze soil cored from the bottom of Curtis Pond to determine if there is a significant change in these characteristics below the accumulated sand and sediment. Finally, Buschert will monitor phosphorus levels in Curtis Pond and effluent to see how they relate to sediment levels. This project has the potential to benefit the Arboretum by shedding light on the potential for sediments to be a source or sink for phosphorus in stormwater, which may inform future management decisions for Curtis Pond.