Progress 06/18/03 to 06/18/08
Outputs
OUTPUTS: Sarracenia purpurea (the northern pitcher plant), a carnivorous wetland plant inhabiting low nutrient, wetlands in North America, is a species of increasing conservation concern in forested regions. Questions surrounding the planning of successful restoration of S. purpurea center on issues of species and population level genetic differentiation, population adaptation to environmental pressures, and accurate and ecologically useful definitions of subspecies. This research explored patterns of genetic and morphological variation across the range of S. purpurea, invalidating previous descriptions of two S. purpurea subspecies, defined primarily on morphology. Geographic area subspecies definitions, dividing populations of S. purpurea into Midwest, North East Coast, and South East Coast, prove more ecologically viable for planning restoration in wetlands. Natural field-measured morphological variation in S. purpurea is strongly tied to local habitat types, particularly responding to alterations in ammonium, calcium, and sulfate concentrations. Of the three habitats that S. purpurea inhabits (Sphagnum peatlands, sand savannahs, and marl fens), plants growing in marl fens are often smaller in both leaf and flower size. Common garden exploration of seedling responses to altered pH and nutrient concentrations showed the majority of morphological expression in S. purpurea as a response to altered environmental characters and not locally adapted phenotypic plasticity. S. purpurea populations exhibit over all low genetic variation within and among different populations regardless of native habitat type or historic subspecies definitions but strong morphological variation in response to local environmental variation. PARTICIPANTS: PhD graduate student TARGET AUDIENCES: PhD work contributes to the knowledge base to restore critically important wetlands within forested regions of the Eastern U.S. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This research partially supported one PhD through her time at Michigan Tech. Her work contributes to the knowledge base to restore critically important wetlands within forested regions of the Eastern US. It also demonstrates the importance of genomics in answering questions dealing with species development and plant ecology.
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
The purpose of this study is to characterize the breeding patterns, genetic diversity, and potential habitat adaptations of Sarracenia purpurea the northern pitcher plant in forested wetlands in the Great Lakes Region. Many federal and state agencies have shown interest in the importance of including this plant species in wetland restoration plans. In order to perform successful restoration, there is much still to learn about Sarracenia purpurea and how it interacts with surrounding communities. One issue we are examining is the pattern of gene flow that exists between established populations around the Great Lakes. Some of these populations are found on potential isolated island systems such as Isle Royale National Park and the Apostle Islands National Lakeshore. We are attempting to examine if these island populations are genetically different from mainland populations on the Keweenaw Peninsula, Sleeping Giant Provincial Park in Canada and Pictured Rocks National
Lakeshore. This would hopefully give an idea of dispersal distances of the plant, gene flow across long distances and if the plant tends to adapt to individual microhabitats. To answer this issue in 2003 we located forested peatlands on Isle Royale, Sleeping Giant, and the Keweenaw Peninsula. Genetic material was collected and the populations were surveyed for plant number, leaf number, flower number and fruit number, morphological measures with which to compare plant populations. We discovered moderate to low genetic diversity in all of the Sarracenia purpurea populations with all of the populations fairly similar genetically. The Canadian populations were smaller in all morphological characteristics and slightly different genetically from the Keweenaw and Isle Royale populations. The Canadian populations are in an area dominated by limestone bedrock, unlike the Keweenaw and Isle Royale areas. Limestone tends to create fairly alkaline conditions and Sarracenia purpurea tends to
inhabit very acidic environments. The physical and genetic differences observed in populations could be related to different bedrock materials and pH quality of the Sarracenia purpurea habitats. To further answer this question, in the summer of 2005 and 2006 we located populations of Sarracenia purpurea in more wetlands around the Great Lakes region. We hoped to encompass a variety of bedrock and pH types with this sampling method. Populations were surveyed and sampled in the same manner as the previous sites and DNA analysis is currently in progress. In the summer of 2007, sites will be located in a transect through North American running north-south to encompass the entire range of Sarracenia purpurea. This will hopefully allow an analysis of how closely adapted Sarracenia purpurea populations are to their local microhabitat and help design broad and local restoration and conservation plans.
Impacts
This research provides valuable information to land managers, National Parks, and ecosystem restoration planners. Forested peatlands are increasing in the focus of wetlands restoration and creation for a number of reasons: potential for carbon sequestration, water quality purification, and the unique nature of the habitat. In this study we expected to see that isolated populations would be genetically different due to limited gene flow across Lake Superior. If we had seen this then restoration would require seed sources from localized regions, sometimes difficult with endangered species. Instead we saw no real differences related to isolation. When restoring populations and reintroducing S. purpurea, seeds and plants can be taken from any number of locations. This is important for areas such as Indiana where there are very few populations left. Seed sources can be selected from areas of dense S. purpurea populations and not put a strain on the areas where the plant is
endangered. The Canadian populations were morphologically and genetically different from the other populations. This small genetic differentiation was not related to distance or isolation but to the bedrock and substrate type of the region. It appears that although the plant prefers acidic conditions, it can grow in alkaline regions. These populations appear to be adapted both morphologically and genetically to the alkaline condition. This indicates that restoration requires an examination of the substrate quality as an important consideration when looking at seed sources and ecosystem type.
Publications
- Karberg, Jennifer; Gale, Margaret. 2005, Genetic Diversity and Distribution of Sarracenia purpurea (Sarraceniaceae) in the Western Lake Superior Basin. Canadian Journal of Botany (in press)
- Karberg, Jennifer; Gale, Margaret; Beske-Diehl, Suzanne. 2005 Influence of Wetland Development by Geology: Isle Royale National Park and the Keweenaw Peninsula, MI (in preparation).
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