The Lack of Favorable Responses of an Endangered Pitcher Plant to Simulated Habitat Restoration.
ABSTRACT- Restoring habitat structure and fire regimes that existed before active and inadvertent fire suppression is thought to be critical to maintaining populations of rare plants in fire-suppressed habitats. Nevertheless, the impacts of habitat restoration on most endangered plants are poorly understood. Current theory predicts and empirical studies have shown that the reduction of shade or competition (a goal of many habitat restoration projects in degraded fire-dependent ecosystems) benefits plants adapted to nutrient-poor soils by increasing the benefit-to-cost ratio of adaptations for enhanced nutrient capture. Here, I examined how experimental reduction of neighboring plants in a wet longleaf pine community dominated in the groundcover by shrubs and stump sprouts influenced the growth, reproduction, carnivorous effort, and the benefits of carnivory in a U. S. federally endangered species, Sarracenia rubra ssp. alabamensis. Two years of data showed no significant effects of neighbor reduction or prey exclusion on any of several indicators of plant performance, nor was there any evidence of a hypothesized morphological trade-off between shade avoidance and prey capture. These results were unexpected. Inadequate replication and atypical precipitation patterns were ruled out as possible explanations. The population studied here (unlike that of a common pitcher plant species in a restored habitat) did not exhibit the ability to respond to variation in shade from neighboring plants. Restoring adaptive, plastic responses to fire (and competition) in this species, if possible, will depend on the untested assumption that fire-adapted ecotypes of this species exist within habitats that have experienced prolonged fire suppression.
Key words: longleaf pine savannas, fire regime restoration, adaptive phenotypic plasticity, Sarracenia alabamensis
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