26 March 2008

Prescribed Fire Collaboration is Enhancing Endangered and Threatened Species Habitat

The mechanical treatment and prescribed fire in the Titusville Wellfield natural scrub community is demonstrating success. The once overgrown scrub habitat is being restored to optimal condition. Federally listed threatened Florida Scrub-Jays, state listed Threatened Gopher Tortoises, and the state listed Endangered Dicerandra thinicola (Titusville Mint) are colonizing the newly restored/managed burn block. The mechanical treatment and prescribed fire were conducted in a collaborative team effort and with a grant from the US Fish & Wildlife Service to the City of Titusville, who owns the large wellfield refuge.

Summary of Dicerandra thinicola Initial Response to Management Treatments at the Titusville Wellfield

Eric Menges, Suzanne Kennedy, Stacy Smith
21 February 2008

We have completed two censuses in our Dicerandra thinicola plots (November 2007, February 2008) since the chopping and burning treatments were imposed during the summer of 2007. Although we have not analyzed these data, we thought it would be useful to share our observations.

We were able to relocate all of our study plots that had been previously set up in the treatment area using GPS.

Many D. thinicola plants survived the partial uprooting caused by the mechanical chopping treatment and the subsequent patchy fire. The surviving plants appear quite healthy; many flowered profusely in the fall of 2007 and many have grown very large, with large vegetative flushes, since the disturbances.

New D. thinicola seedlings have appeared in many of the treated plots. The seedling numbers vary from none to many hundreds of new seedlings per plot. The positive response of seedlings this winter may reflect favorable weather conditions; and drier winter conditions in other years might mean that D. thinicola seedling responses to treatments would not be as good.
We don’t know how this species would respond to fire-only (without initial mechanical fuel reduction treatment). Fire produces positive seedling responses in D. thinicola’s congener D. frutescens (which occurs over 150 miles away on the Lake Wales Ridge). We would, therefore, predict D. thinicolat’s seedling response to also be strongly positive from a fire-only treatment. We would expect that chopping, without subsequent fire, would not produce a strong seedling response.

New seedlings appeared within plots that previously had plants and also in one of our plots that only had nearby plants outside the plot (a few meters away). Large areas of treated scrub habitat that lacked plants before treatments still lack plants. This emphasizes the limited dispersal ability of D. thinicola. We believe that active seed introductions will be necessary to substantially expand the spatial coverage of D. thinicola. We are interested in trying seed introductions in conjunction with the next round of treatments.

We have added two new study plots in areas that are not slated for the next round of treatments as controls, so we can continue to have a basis for comparison of D. thinicola responses.


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