Responses Of The Clonal Florida Endemic Shrub Polygonella Myriophylla To Fire And Mechanical Disturbance

Abstract

There is an unsettled debate on the benefits of mechanical disturbance for native species in fire-prone habitats. We compared the demographic effects of fire and mechanical treatments (Gyro-tracing) on Polygonella myriophylla, a prostrate clonal shrub listed as endangered and narrowly endemic to pyrogenic scrub ecosystems in south-central Florida. This species is commonly found in gaps within a matrix dominated by resprouting shrubs, but also occurs under other shrubs and along the shoulders of adjacent road-side habitats. We designed and executed a replicated (that plots per treatment, 1 ha per plot; total 147 initial plants) experiment including plots burned, mechanically chopped, with both treatments and without treatments at the Lake Wales Ridge Wildlife and Environmental Area - Carter Creek in Highlands County, central Florida (2005-2008; treated in summer of 2005). Cumulative mortality of standing P. myriophylla after 3 y was higher in burned plots (> 80%) than in chopped-only and untreated plots (∼ 50 % and ∼ 40 % respectively). Post disturbance growth in canopy area among the surviving plants was consistently higher in mechanically disturbed plots compared to untreated plots and intermediate burned conditions. We found three putative seedlings, accounting for less than 3% of the initial genets, before treatment application, but many seedlings after treatments. Seedling recruitment (∼ 90) post-treatment was higher in disturbed plots, highest when both treatments occurred together, and almost null in untreated plots. Recruitment was highest in the first-year post disturbance (70%), decreasing in subsequent years. Disturbances may improve the persistence of P. myriophylla by increasing recruitment and individual growth, however; fire and mechanical disturbance should be used with caution for this species given many plants died during treatment.

Publication Date

10-1-2018

Publication Title

American Midland Naturalist

Volume

180

Issue

2

Number of Pages

175-188

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1674/0003-0031-180.2.175

Socpus ID

85054515701 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85054515701

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