Missouri bladderpod (Lesquerella filiformis Rollins) was listed as Federally Endangered in 1987. Five populations are found at Wilson’s Creek National Battlefield. This diminutive winter annual is restricted to limestone glades and rock outcrops in southwestern Missouri and northwestern Arkansas. Habitat conversion for urban development or agriculture threatens this species range-wide. The habitat structure of the limestone glades has been altered by woody species encroachment, a result of suppression of periodic wildfires that maintained an open character to glade vegetation. Glade habitat has also been altered and threatened by exotic species establishment; of particular concern are annual exotics such brome grass (Bromus species), which compete directly with Missouri bladderpod and can crowd it out (Thomas and Jackson 1990). Current management practices have been centered upon exotic species control and the reduction of woody vegetation by the combination of manual removal and small-scale prescribed fire.

Monitoring questions and approach

1. How does abundance fluctuate over time?

   • Annual censuses to track the abundance of the species through time. Population size has been observed to fluctuate widely from year to year, with the number of plants surviving to maturity ranging over several orders of magnitude – in some years none may survive to reproduce, so that local population persistence depends on the resilience of the seed bank.

2. How does plant occurrence, survivorship and reproduction vary with habitat characteristics? Which factors determine the population size for this species?

   • Habitat data are collected simultaneously with annual abundance data so that local abundance patterns can be correlated with habitat characteristics.

   • Demographic sampling is undertaken periodically to determine which factors limit population size of Missouri bladderpod, and how survivorship and reproduction vary across glade microhabitats. Microsite conditions vary tremendously so that plants growing within a few meters of one another display drastically different survival and reproductive rates (Thomas 1996). Information on how survivorship and reproduction vary with habitat characteristics over time can be used to develop a more informed and effective habitat management plan for Missouri bladderpod.

3. How is the limestone glade habitat changing over time?

   • Glade vegetation is being monitored in two ways: 1) three vegetation transects placed at the largest population and sampled periodically; and 2) glade-wide habitat data collected systematically for two populations so that multi-year comparisons can be made.

Protocol

• Kelrick, M.I. 2001. Missouri bladder-pod monitoring protocol for Wilson's Creek National Battlefield. U.S. Geological Survey, Northern Prairie Wildlife Research Center, Missouri Field Station, Columbia, MO. 28 pp.