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ABSTRACTS Introduction to Mead’s milkweed Notwithstanding these discoveries, the (Asclepias meadii Torr.) and its habitat species faces serious threats. Roughly 60% of populations for which counts are available Craig C. Freeman, R. L. McGregor never have been observed with more than 25 Herbarium & Kansas Biological Survey, ramets. Habitat destruction and alteration 2045 Constant Avenue, Lawrence, KS from residential and urban development, and 66047-3269, [email protected] from agricultural changes, continue to impact populations. Annual haying, a common land Mead’s milkweed (Asclepias meadii Torr.) is use on prairies in Kansas and Missouri, a long-lived, perennial herb endemic to the prevents full development of fruits and is central United States. Plants are self- implicated in reduced genetic diversity incompatible, pollinated by small bees, and within populations on hay meadows. Sericea can spread by rhizomes. Seed dispersal is by lespedeza [Lespedeza cuneata (Dum. Cours.) wind. Populations occur on dry-mesic to G. Don] may pose a new threat to some mesic, glaciated or unglaciated tallgrass populations. prairies or glades. Substrates are sedimentary (limestone or sandstone) or, Mead’s Milkweed Recovery Plan rarely, igneous. Described 150 years ago, few extant populations were known until the Kristopher Lah, Endangered Species 1980s. When listed as threatened in 1988, Coordinator, U.S. Fish and Wildlife Service, Mead’s milkweed was known from 81 extant Chicago Field Office, 1250 S. Grove, Suite populations. Today, 225 extant populations 103, Barrington, IL 60010, are known in 34 counties in Illinois, Iowa, [email protected] Kansas, and Missouri. Distribution of these populations is highly skewed toward the The Mead’s Milkweed (Aesclepias meadii) southwest edge of the historic range. Nearly Recovery Plan was completed in 2003. Like 91% of extant populations are in 23 counties most federal recovery plans it consists of in eastern Kansas and west-central Missouri, three chapters, introduction; recovery; and largely in the southern Central Irregular implementation. This presentation will Plains ecoregion. Another 4% of extant briefly cover chapter one, introduction, of the populations are in eight counties in southwest plan which provides a description of the Iowa and north-central Missouri, in the species, its status, habitat, and biology. This northern half of the Central Irregular Plains. presentation will focus mainly on the Remaining extant populations are in the recovery plan’s chapters that mesh with the Ozark Highlands of southeast Missouri and theme of the symposium, recovery and Interior River Lowlands of extreme southern implementation. Chapter two of the plan Illinois. Populations from the Central Corn identifies the recovery objective to delist the Belt Plains (northern Illinois, northwest species with populations representative of the Indiana), Driftless Area (southwest range of the species’ habitats and geographic Wisconsin), and Western Corn Belt Plains distribution. A brief description will be (east-central Iowa) are historic. Surveys for discussed of the plan’s framework to meet new populations continue to be fruitful; the recovery criteria with a minimum number systematic inventories in Kansas in 2004 and of viable populations across Mead’s 2005 yielded 39 new populations. milkweed’s range. Chapter two continues with a description of the actions that will be estimation of population size and patch accomplished in order to reach the recovery survival using mark-recapture methodologies criteria. Chapter three of the plan more typically used in animal studies. Our summarizes the actions that need to be study has revealed that population size at the implemented to recover the species in a site is likely to exceed 125 patches despite schedule that provides an approximation of the fact that many years have many fewer the cost and timeframe that actions may be patches. Yearly patch survival is high accomplished. Hardcopies of the plan will (geometric mean = 0.96), and can only be be available for attendees and can be accurately assessed with long term data sets. downloaded at: Recruitment, as measured by the appearance http://www.fws.gov/midwest/Endangered/pla of new patches, occurs frequently enough to nts/meads-fnl-rp.pdf. balance the 4% mortality, suggesting that population numbers are being maintained Research on Mead’s milkweed at the over time. Fruit production at the site is Rockefeller Prairie in eastern Kansas: A variable, but never exceeds 45 pods across 19-year perspective the site in a single year, and often is much smaller. The best predictor of fruit number is Helen Alexander, Department of Ecology the number of flowering stems, which in turn and Evolutionary Biology, University of is often higher in years with dormant season Kansas, Lawrence, KS, 66045, burning. The variability observed in both [email protected] fruit number and number of new patches Dean Kettle, Kansas Biological Survey, suggest that recruitment may be often 2101 Constant Avenue, Lawrence, KS, episodic in nature. 66047, [email protected] Norman Slade, Department of Ecology and Factors limiting Mead’s milkweed fruit Evolutionary Biology, University of Kansas, production in eastern Kansas Lawrence, KS, 66045, [email protected] Galen Pittman, Kansas Biological Survey, Emily Grman, W.K. Kellogg Biological 2101 Constant Avenue, Lawrence, KS, Station, 3700 E. Gull Lake Dr., Hickory 66047, [email protected] Corners, MI, 49060, and Department of Plant Biology, Michigan State University, East Nineteen years of observation, using a Lansing, MI, 48824, [email protected] standard monitoring protocol, has provided Helen Alexander, Department of Ecology new insights into the population biology of and Evolutionary Biology, University of Mead’s milkweed in a 4 ½ hectare prairie Kansas, Lawrence, KS, 66045, remnant in northeastern Kansas. Our initial [email protected] question (is the population increasing, decreasing, or staying constant in numbers Most remaining populations of Mead's over time?) has proved to be challenging milkweed produce very few fruit, threatening since milkweed patches (i.e. spatially their long-term viability. In Rockefeller aggregated groups of stems, which Prairie in 2002, we conducted an approximate genetic individuals) are difficult observational study to test hypotheses of to detect in the dense prairie, and individual factors limiting fruit production. We found plants can survive, but have no above ground that lower rates of pollinator visitation were parts in some years. We have thus combined not associated with lower fruit production, our analyses of observed patches with suggesting that pollen limitation was not 2 important in this population. Larger plants From 2001 until 2006 no prescribed burns tended to produce more fruit, indicating that were conducted at either site. General trends resource limitation may have lowered fruit observed over the monitoring period at the production. However, impacts of both pollen Weimer Hill site were an increase in the and resource limitation were outweighed by number of plants with multiple stems, an vertebrate herbivory, which caused a 63% increase in the number of stems inventoried, reduction in the number of plants capable of a decrease in the number of flowering stems, producing fruit. Understanding the factors a decrease in the average height of the stems, limiting fruit production in a natural and a decrease in the average width of the population can help us increase fruit widest leaf. The Mina Sauk Falls population production and population growth in natural exhibited an increase in the number of stems and managed populations of Mead's inventoried, and an increase in the number of milkweed. flowering stems over the same time period. Mead’s milkweed monitoring at Taum 1- "Genetic Variability in the Federal Threatened Mead's Milkweed, Asclepias meadii Torrey (Asclepiadaceae), as Sauk Mountain State Park, Missouri Determined by Allozyme Electrophoresis." Diane L. Tecic, Jenny L. McBride, Marlin L. Bowles, Daniel L. Michael P. Currier, Missouri Department of NickrentAnnals of the Missouri Botanical Garden, Vol. 85, No. 1 (1998), pp. 97-109. Natural Resources, P.O. Box 176, Jefferson City, MO, 65102, [email protected] Population status, propagation, and Dan Drees, Missouri Department of management for Asclepias meadii (Mead’s Conservation, P.O. Box 180, 2901 W. milkweed) in Missouri Truman Blvd., Jefferson City, MO 65109. Emily S. Horner, Missouri Department of In 1991, after a winter prescribed burn, Conservation, P.O. Box 368, Clinton, MO Mead’s Milkweed was found in the St. 64735, 660-885-6981 Francois Mountains of southeast Missouri on igneous substrates on a lobe of Proffitt There are 59 known sites in Missouri with Mountain know as Weimer Hill. In 1995, the extant Mead’s milkweed populations population was described as "providing the documented within the Missouri Natural largest viable seed source for restoration on 1 Heritage Database. Over the past few acidic, nutrient poor soils ." The Missouri decades periodic monitoring of these sites Department of Natural Resources manages has occurred, with longer term surveys at the igneous glades and associated woodlands Paintbrush Prairie and Taum Sauk State with prescribed fire. The area has had 4 Park. Overall, the majority of Missouri prescribed burns over the past 16 years. populations contain < 15 plants, from initial Stewardship includes monitoring populations surveys in the 1970’s and 1980’s and in of threatened or endangered

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