RECOVERY PLANNING AND REINTRODUCTION OF THE FEDERALLY THREATENED PITCHERS THISTLE (CIRSIUM PITCHERI) IN ILLINOIS

Pitcher's thistle (Cirsium pitcheri) is a narrowly distributed endemic of the western Great Lakes shorelines. This monocarpic herb is an obl igate colonizer of >70% open sand habitat in early- to mid-successiona l vegetation maintained by intermediate levels of disturbance or creat ed by stochastic disturbance events. Its persistence can be modeled wi thin a metapopulation framework, where interacting populations react t o environmental factors independently, facilitating metapopulation per sistence. The habitat requirements of Pitcher's thistle have made it e xtremely vulnerable to shoreline erosion, development, and recreationa l use. It is federally listed as threatened and state listed as endang ered or threatened throughout its range in the United States. In Illin ois, Pitcher's thistle was collected at least twelve times from the La ke Michigan shoreline between 1862 and 1919; it then apparently disapp eared, probably as a result of the combined effects of increasing huma n activity, lake level fluctuations, collecting, and other chance even ts. Restoration of Cirsium pitcheri in Illinois is an objective of the federal recovery plan, and Illinois Beach State Park contains the onl y remaining Illinois dune systems where it might be reintroduced. To i dentify appropriate restoration habitat, the vegetation at Illinois Be ach was compared to the nearest occupied Cirsium pitcheri habitats, at Indiana Dunes National Lakeshore and at Kohler-Andrae State Park in W isconsin. Ordination and cluster analysis demonstrated strong similari ties between upper beach, foredune, secondary dune, and dunefield habi tat in Illinois and similar thistle-occupied habitats in Indiana and W isconsin. However, at Illinois Beach State Park only the secondary dun e habitat appeared to be free from shoreline erosion and recreational impacts. Propagated plants from Indiana and Wisconsin seed sources wer e introduced into this habitat in 1991, with greater survivorship amon g the Indiana plants. Experimental establishment of additional cohorts from seeds and propagated material is needed to further identify appr opriate microhabitat, while shoreline protection, control of recreatio n, and periodic reintroduction may be required to maintain a metapopul ation at Illinois Beach.