Effects of Time-Since-Fire and Microhabitat on the Occurrence and Density of the Endemic Paronychia chartacea ssp. chartacea in Florida Scrub and Along Roadsides

Abstract

Conservation of an imperiled plant species requires an understanding of its local occurrence and density in relation to habitat variation. Paronychia chartacea ssp. chartacea is a federally threatened species restricted to gaps in fire-maintained Florida rosemary scrub and to roadside sites that mimic scrub gaps. To assess the effects of time-since-fire and microhabitat on the occurrence and density of Paronychia populations, we conducted surveys of 119 scrub gaps and 16 roadside macroplots. In rosemary scrub, we found that the frequency of gap occupancy decreased with time-since-fire and that Paronychia occurrence and density were greater in the centers of large gaps than in small gaps or large gap edges. In roadside sites, the distance from adjacent rosemary scrub did not affect the presence of Paronychia, but density increased with distance from rosemary scrub vegetation. Paronychia densities in roadside sites were most similar to densities in recently burned rosemary scrub. Time-since-fire and microhabitat quality affect the occurrence and density of Paronychia and should be considered in management of Paronychia populations.