Plant Conservation

Research Questions

Restoration of rare plants has become critical for insuring their long-term survival. Our work with rare plants asks: What ecological and biological factors can be managed to help maintain or restore populations? What are practical ways to restore different plant species populations?, What genetic factors affect restoration potential? and Do restored populations have long-term viability? Much of our work is with the federal listed Meadís milkweed, Pitcherís thistle, and the eastern prairie fringed orchid.

Selected References

Bowles, M.L. & C. Whelan (editors). 1994. Restoration of Endangered Species: Conceptual Issues, Planning and Implementation. Cambridge University Press.  link to Cambridge University Press

Bell, T.J., M.L. Bowles, & K.A. McEachern. 2003. Projecting the Success of Plant Population Restoration with Viability Analysis. Pages 313-348 in, C.A. Brigham & M.W. Schwartz (Eds), Population Viability in Plants. Springer-Verlag, Berlin, Heidelberg. pdf


Meadís milkweed is an obligate outcrossing rhizomatous herbof late-successional prairies, and occurs as non-reproductive clones in smaller remnants. We have developed a restoration strategy based on its genetic diversity, using genotypes from multiple seed sources to assure reproductive potential in restorations. We have used hand pollination of nursery grown plants to produce propagules for multiple restorations. Monitoring indicates that seedling establishment is enhanced by fire, that growth from seedling to reproductively mature plants requires decades, and that establihsment of viable populations may require longer time periods.

Selected References

Bowles, M.L., J.L. McBride. & R.F. Betz. 1998 Management and Restoration Ecology of the federal threatened Mead's milkweed, Asclepias meadii, (ASCLEPIADACEAE). 1998. Annals of the Missouri Botanical Garden. 85:110-125. pdf

Tecic, D, J. McBride, M. Bowles, & D.L. Nickrent. 1998. Genetic variability in the federal threatened Mead=s milkweed, Asclepias meadii Torrey (ASCLEPIADACEAE) determined by allozyme electrophoresis. Annals of the Missouri Botanical Garden. 85:97-109.  pdf

Bowles, M, J. McBride, & T. Bell. 2001. Restoration of the federally threatened Mead's milkweed. Ecological Restoration 19:235-241. pdf

Hayworth, D.A., M.L. Bowles, B.A. Schaal, & K.E. Shingleton. 2001. Clonal population structure of the federal threatened Meadís milkweed, as determined by RAPD analysis, and its conservation implications. Pages 182-190 in, N.P. Bernstein & L.J. Ostrander (editors), Seeds for the Future Ė Roots of the Past: Proceedings of the Seventh North American Prairie Conference. North Iowa Area Community College, Mason City, Iowa.  pdf

Pitcherís thistle is a monocarpic disturbance-adapted herb restricted to sand dunes of the western Great Lakes. We are using repeated demographic monitoring and viability analysis to project population growth of restored populations. Click here to visit the Cirsium pitcheri research website. This work demonstrates population growth,but vulnerability of small populations to stochastic processes.

Selected References

Bowles, M., R. Flakne, K. McEachern, & N. Pavlovic. 1993. Recovery Planning and reintroduction of the federally threatened Pitcher's thistle (Cirsium pitcheri) in Illinois. Natural Areas Journal 13:164-176. pdf

McEachern, K., M. Bowles, & N. Pavlovic. 1994. A metapopulation approach to recovery of the federally threatened Pitcher's thistle (Cirsium pitcheri) in southern Lake Michigan dunes. 1994. Pages 194-218 in, M. Bowles, & C. Whelan (editors), Restoration of Endangered Species: conceptual issues, planning and implementation. Cambridge University Press. pdf

The eastern prairie fringed orchid requires pollination by hawkmoths, soil fungi for seed germination and seedling establishment, and appropriate soil conditions for growth. Use of hand pollination to produce seeds for restoration creates concern over seed sources, as well as evaluation of sites for restoration. Our work has indicated an interaction between this speciesí breeding system and crossing rates, ranging from inbreeding depression to heterosis. We have identified obligate soil fungi required for seedling establishment, and have characterized soil conditions required to support populations.

Selected References

Bowles, M.L. 1983. The tallgrass prairie orchids Platanthera leucophaea (Nutt.) Lindl. and Cypripedium candidum Muhl. ex Willd.: Some aspects of their status, biology, and ecology, and implications toward management. Natural Areas Journal 3(4):14-37.  pdf

Sheviak, C.J. & M.L. Bowles. 1986. The prairie fringed orchids: a pollinator-isolated species pair. Rhodora 88:267-290. pdf

Zettler, L.W., S.L. Stewart, M.L. Bowles & K.A. Jacobs. 2001. Mycorrhizal fungi and cold-assisted symbiotic germination of the federally threatened eastern prairie fringed orchid, Platanthera leucophaea (Nuttall) Lindley. American Midland Naturalist 145:168-175. pdf

Bowles, K. A. Jacobs, L. W. Zettler and T. Wilson Delaney. 2002. Crossing effects on seed viability and experimental germination of the Federal threatened Platanthera leucophaea (Orchidaceae). Rhodora (104)14-30. pdf

Bowles, M., L. Zettler, T. Bell & P. Kelsey. 2005. Relationships between soil characteristics, distribution and restoration potential of the federal threatened eastern prairie fringed orchid, Platanthera leucophaea (Nutt.) Lindl. The American Midland Naturalist (154)273-285. pdf

Zettler, L.W., K.A. Piskin, S.L. Stewart, J.J. Hartsock, M.L. Bowles & T.J. Bell. 2005. Protocorm mycobionts of the Federally threatened eastern prairie fringed orchid, Platanthera leucophaea (Nutt.) Lindley, and a t echnique to prompt leaf elongation in seedlings. Studies in Mycology 53. pdf