The Effects of Woody Plant Management on Habitat Conditions, Plant Demography, and Transplantation Success of the Endangered Orchid Spiranthes parksii Correll
Abstract
Spiranthes parksii Correll is a federally endangered species endemic to 13
counties of the Post Oak Savanna in Central Texas. Approximately 700 S. parksii are
located on the Brazos Valley Solid Waste Management Agency’s (BVSWMA) Twin
Oaks landfill property in Grimes County, Texas. The opportunity to study S. parksii was
created through the mitigation requirements set forth by the United States Fish and
Wildlife Service (USFWS) on the property.
Studies were designed to assess the effect of woody plant management on the
target species with the overall goal of enhancing the establishment, growth, and
reproductive success of S. parksii. Evergreen midstory shrub removal and woody patch
clearing to produce varying sized open grassland and woody patches to increase edge
effect were studied to determine their influence on habitat for S. parksii. S. parksii were
transplanted from at risk areas to permanently protected areas to evaluate potential
effective procedures for transplanting of the species.
Seasonal variability in S. parksii and Spiranthes spp. numbers were common
across all studies, however, flower production in the fall was positively correlated with
the summed January through March precipitation. In general, the removal of encroached
woody plants resulted in a positive orchid response, though poor herbicide efficacy may
limit this treatment effect in the long-term. Transplantation of S. parksii into areas which
received woody plant management resulted in at least a 50% survival rate 3 years post-transplant.
Citation
Bruton, Richard Kyle (2014). The Effects of Woody Plant Management on Habitat Conditions, Plant Demography, and Transplantation Success of the Endangered Orchid Spiranthes parksii Correll. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /152475.