Patterns of demographic characteristics of Cirsium pitcheri at Piping Plover nesting sites in northern Michigan.

Abstract

My objective was to gather baseline information on abundance and distribution on the populations of Cirsium pitcheri in the understudied areas of northern Lake Michigan, near UMBS. I set out to determine densities and proportions of plants at several life history stages at each site, so I could make comparisons of vigor among sites. My findings are part of a larger study conducted by Drs. Francesca Cuthbert, Brian Scholtens, and Claudia Jolls. Their study is designed to take inventories of multiple species assemblages of rare taxa within the freshwater dune systems of the Great Lakes, with a long term goal of initiating a landscape level management plan. By observing and recording basic ecological patterns of Cirsium pitcheri, I started to realize how many factors can influence distribution and patterns of abundance in a plant population. Abiotic factors on many time scales, other plant and animal taxa, human activities, and every combination of the three can influence the demography of a rare and sensitive plant species. Variation in location and habitat types lead me to believe that perservation of habitat for Pitcher's thistle requires long term preservation of multiple, large, diverse, intact dune systems, with restricted human influence. If at all possible, the preservation of corridors of beach or dune for the movement and interaction of PItcher's thistle would help preserve the integrity of the metapopulation. Landscape scale management techniques would be well suited to conservation efforts of Cirsium pitcheri. Because large pieces of habitat are needed to ensure long term success of the metapopulation, it would be simple to coordinate efforts for the other taxa of special concern in the Great Lakes dune system. Cirisum pitcheri is probably the least habitat specific species on the list of endemic and rare taxa, so areas set aside to preserve other species would most likely support PItcher's thistle as well. However, it is the only taxa that has metapopulation dynamics which require the ability to change with habitat through space and time. Therefore, Cirsium pitcheri should provide support for the argument to merge the pieces of dune micro-habitats allocated for preservation of individual taxa, and initiate a unique landscape wide conservation effort.