ARBORETUM NEWS (PRESS RELEASES)

Science Day Celebrates 10th Anniversary

TUESDAY, MARCH 23, 2010

Plants, butterflies, beetles, bees, dragonflies and damselflies were all featured in the tenth annual presentations of research at the Arboretum…not to mention a culinary version of a cichlid fish, formed into to “Arboretum Oscars” awarded to Brad Herrick and Mark Wegener for their service to the research program as “Best Supporting Role” and “Best Screen Play(er)”, respectively. The festive event drew attendees from WDNR, FWS, local consulting groups, UW students, Arboretum guides and staff, and members of the public (including a “SwampLover” from Mazomanie). The audience heard three kinds of reports—discoveries of species we never knew we had, documentation of species that Arboretum lands have lost, and ways to begin new restoration efforts.

In the former category, Kyle Johnson collected and identified moths and butterflies at Raymond Rd, Bolz, Faville, McKenna Pond, Observatory Woods, Oliver Prairie, Abraham’s Woods, Loddes Mill Bluff, and Finnerud Forest. He found many “microlepidoptera”—moths that are much smaller (under 3 mm long) than names like Dyseriocrania griseocapitella, and Feralia c omstocki might suggest. Johnson thinks the Arboretum might have 1500 species of moths, of which 90% are yet to be documented. Notably, he found the rare Silphium borer at Greene and Curtis Prairies.

Some of those moths and butterflies also starred in Nicole Rafferty’s talk about pollinators in Curtis Prairie. Rafferty is asking whether or not insects will be able to pollinate prairie forbs that are initiating flowering weeks ahead of their normal time, due to changing climate. Although her results do not indicate an imminent crisis, she remains puzzled by low seed set in butterfly weed. Might there be “hidden mismatches” in some pollinators that cannot adapt to earlier flowering? We will learn more next year, as she continues her data analysis.

Meanwhile, which species have gone missing? In his keynote address, Dr. Robert Bohanan described his ongoing study of dragon- and damselflies in Lake Wingra, emphasizing sampling efforts of teachers and high school students who have so far collected only 19 species. Bohanan thinks the lake should support at least 50 species, but he’s not sure what more have not been found. The paucity of larval forms is a clue—eggs occur among the vegetation, but where are the larvae?

Also missing are many species of understory plants in Observatory Woods, where Erika Mudrak has been retracing the steps of Dr. Robert Burgess, whose 1959 map of the vegetation showed larger areas of herbaceous plants and much more invasive buckthorn. American elm, however, is making a “big comeback.”

Sara Rueth documented many prairie plants that disappeared following the prolonged flooding in June 2008. Most notable is prairie dropseed, which was a dominant grass in 2008. An additional 8 species have also dropped out of the “top ten” that were present in 2005; these include prairie fringed and lady slipper orchids. Rueth’s new data document a shift from prairie to wetland species. Given her baseline, future censuses can record some recovery of lost diversity. Rather than reintroducing lost species at this time, the Arboretum plans to watch the dynamics to see if populations can recover from catastrophic flooding.

Now that some Arboretum lands are becoming wetter, due to climate change and/or urban runoff, Sally Gallagher offers advice on how to grow and restore tussock sedge, a species that could re-establish sedge meadow vegetation. New stormwater-management structures are one place where this native plant could be introduced. Gallagher’s experiments indicate that growers could add nitrogen to pots to increase overall biomass of seedlings and plugs and that much of the extra biomass will develop below ground where it could help stabilize soil. Unlike most plant species, nitrogen additions increased the allocation of biomass to roots and rhizomes, compared to shoots.

Beth Lawrence further demonstrated the value of restoring tussock sedge in her study of tussock composition (mostly organic matter, not sediment) and persistence. In Curtis Prairie, soil under tussocks had 2 kg of carbon per square meter, and the tussocks added another 1.2 kg more. So Beth asked if that carbon is persistent or vulnerable to decomposition. After incubating subsamples of tussocks and soil for over a year in a growth chamber, Lawrence learned that tussock carbon is persistent, but not as resistant to decomposition as that in the soil.

With 75 years of research and ten years of reporting results to broad audiences, the Arboretum is fulfilling a core part of its mission, namely, advancing restoration ecology. Visit the research web page for more information and join us next year for more exciting updates!
—Joy Zedler, Arboretum Research Director

Click here to view a schedule for the 2010 program.

Click here to view abstracts from this year’s presenters.

Located between Lake Wingra and the West Beltline Highway at 1207 Seminole Highway, the University of Wisconsin-Madison Arboretum features the restored prairies, forests and wetlands of pre-settlement Wisconsin. This 1,260-acre arboretum also houses flowering trees, shrubs and a world-famous lilac collection. Educational tours for groups and the general public, science and nature-based classes for all ages and abilities, and a wide variety of volunteer opportunities for groups, families and individuals are available.