Abstract. Restoration of the Pinus palustris (longleaf pine)-wiregrass ecosystem of the southeastern United States requires information on reference conditions such as the historical fire regime. Aristida beyrichiana (wiregrass), a keystone perennial bunchgrass, was historically widespread throughout the southeast, but its dependence upon growing season fires for sexual reproduction hastened its decline in the face of decades of human fire suppression. The reproductive response of wiregrass is described by patterns of meristem allocation between competing life history strategies (i.e., vegetative growth vs. sexual reproduction). The temporal link between fire and flowering indicates this allocation was optimized to the historical fire regime through selection. In this study, we used the observed allocation of wiregrass reproductive effort to sexual reproduction as the response variable to examine reproductive response to fire season, using plant size as a covariate. Sexual reproduction was positively associated with plant size. Plants burned during early summer (May-June) produced a greater proportion of inflorescences than did those burned in early spring (March-April) or in late summer (August). Using state records of natural (lightningignited) and anthropogenic (human-ignited) fires from historical (1933)(1934)(1935)(1936)(1937)(1938)(1939)(1940)(1941)(1942)(1943)(1944)(1945)(1946) and contemporary (1998-2010) periods we found that the distribution of maximum wiregrass reproductive output most closely reflected the distribution of historical fires with natural ignition sources. Moreover, while the monthly distributions of historical and contemporary fires were different for anthropogenic ignitions, they did not differ for fires with natural ignitions. Our predictions of peak allocation based upon the biology of wiregrass provide strong support for the use of wiregrass as an indicator of the historical fire season (early summer). Efforts to restore the longleaf pine ecosystem should therefore consider the biological response of wiregrass in planning prescribed fires.

Large home-range size and habitat specificity are two commonly cited ecological attributes that are believed to contribute to species vulnerability. The eastern diamondback rattlesnake Crotalus adamanteus is a declining species that occurs sympatrically with the more abundant canebrake rattlesnake Crotalus horridus in a portion of the south-eastern Coastal Plain, USA. In this study, we use the ecological similarities of the two species as experimental controls to test the role of home-range size and habitat specificity in the imperilment of the eastern diamondback rattlesnake. We used analysis of variance to investigate differences in home-range size between the two species, and home-range selection was modeled as habitat use versus availability with a case control sampling design using logistic regression. We failed to detect differences in home-range size between the two species; therefore, we could not identify home-range size as an attribute contributing to the imperilment of eastern diamondback rattlesnakes. Eastern diamondback rattlesnakes selected pine savannas to a degree that suggests that the species is a habitat specialist. Of the two factors examined, habitat specificity to the imperiled longleaf pine ecosystem may be a significant contributor to the decline of the eastern diamondback rattlesnake.

Scientific models that guide restoration/management protocols should be reviewed periodically as new data become available. We examine ecological concepts used to guide restoration of pine savannas and woodlands, historically prominent but now rare habitats in the southern North American Coastal Plain. For many decades, pine savanna management has been guided predominantly by a biome-centric succession model. Pine savannas have been considered earlysuccessional communities that, in the absence of fire, transition rapidly toward closed-canopy hardwood forests. Recurrent fires have been viewed as exogenous disturbances that maintain savanna ecosystems as a sub-climax, blocking succession to an equilibrium steady state (closedcanopy forests). Over recent decades, a vegetation-fire feedback model has emerged in which pine savannas are conceptualized as persistent, non-equilibrium communities maintained by endogenous, co-evolutionary vegetation-fire feedbacks. Endemic plant species are resistant to fires and specialized for post-fire conditions generated by frequent lightning fires, primarily within a distinct fire season. These species produce pyrogenic fine fuels that are easily ignited.The resulting fire regimes, entrained by these vegetation-fire feedbacks, are predicted to result in persistent pine savannas. Local variation over space and time in evolutionary feedback mechanisms between pyrogenic vegetation and fire regimes produces heterogeneous landscapes.Disturbances of these feedbacks, such as human fire suppression, are postulated to result in rapid transition to communities lacking feedback elements, such as closed-canopy forest and those without pyrogenic species. Succession-based management focuses on reversing the transition to forest, primarily by removing hardwoods and reintroducing fire as a disturbance. However, we advocate restoration and management approaches that target reinstitution of functional vegetation-fire feedbacks. Such approaches should favor native pyrogenic plant species and 3 reinstitute fire regimes that mimic historical, evolutionarily derived fire regimes. Vegetation-fire feedback concepts should be useful in addressing resistance and resilience of fiery ecosystems worldwide to inherent changes in feedback mechanisms, constituting a framework useful in addressing global management challenges.

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