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Citation. Davis, M. A. 1992. The effects of pocket gophers on survivorship, growth, and reproduction of large beardtongue. Pages 47-49 in D. D. Smith and C. A. Jacobs, Eds., Proceedings of the Twelfth North American Prairie Conference. University of Northern Iowa Press, Cedar Falls, IA. [1034 LTER]
Abstract. A three-year study examined how pocket gophers affect patterns of survivorship, growth, and reproduction of large beardtongue (Penstemon grandiflorus Scrophulariaceae). With their mound-building and tunneling behavior, pocket gophers create areas with sparse vegetation. Plants growing naturally in areas with pocket gopher disturbances exhibited higher rates of mortality, but surviving plants grew faster and reproduced sooner than other plants. In an experiment in which beardtongue was transplanted into two gopher-proof pens, one with and one without other vegetation, plants growing in the pen with bare soil exhibited higher rates of survivorship, growth and reproduction compared lo the plants in the naturally vegetated pen. A root-removal experiment designed to simulate gopher herbivory showed that root loss of a kind normally experienced by beardtongue resulted in higher rates of mortality. However, reproduction in surviving plants not affected by root removal. The data show that although pocket gophers reduce the survivorship of individual plants, their presence actually helps perpetuate large beardtongue in the landscape.