The effect of habitat structure on reproduction and prey capture of a rare carnivorous plant, Pinguicula lutea

Habitat modification is one of the greatest threats to biodiversity worldwide and the main contributor to the decline of many carnivorous plant species. For carnivorous plants in the Southeast US, including many Pinguicula species (butterwort, Lentibulariaceae), habitat modification via altered fire regime has been implicated in their decline. Despite this decline, limited empirical research has been conducted examining the influence of habitat structure on reproduction and prey capture of carnivorous plant species in this region. The studies described in this thesis aim to address this deficit. Chapter 1 provides a general introduction to carnivorous plants, focusing primarily on Pinguicula species. In this chapter, I describe the results of a series of preliminary studies on Pinguicula lutea (yellow butterwort) to address gaps in knowledge of its basic biology (e.g., breeding system and prey identification) and to develop sampling protocols (e.g., seed set and prey sampling) for further work. Chapter 2 addresses the impacts of habitat structure (i.e., woody, grassy, and maintained) on reproduction and prey capture for Pinguicula lutea in the Florida Panhandle. Lastly, Chapter 3 provides conservation, management, and additional research recommendations for Pinguicula lutea and its congeners. Pinguicula lutea is a carnivorous plant that inhabits fire-dependent longleaf pine savannas of the Southeast US and is listed as threatened in the state of Florida. Based on preliminary studies in 2013, Pinguicula lutea is a self-compatible but outcrossing species. Its primary prey are Collembola and small Diptera. In 2014 and 2015 populations were identified occupying three types of habitat structure: maintained (mowed), grassy (dense Aristida stricta var. beyrichiana), and woody (Hypericum/Ilex mix). Reproductive output was determined by assessing fruit and seed set at each habitat structure. Additionally, prey availability and prey capture were assessed at each habitat structure. In general, habitat structure did not affect reproduction, but did affect the abundance of Collembola, Diptera, and all arthropods combined both in terms of availability and prey capture. Overall, there was a significant difference in total arthropod availability and prey capture among habitat structures where grassy habitats tended to have fewer arthropods available and captured prey than maintained or woody habitats. In addition, arthropod availability and prey capture were higher in 2015 than in 2014. Microclimatic conditions (e.g., light availability) associated with each habitat structure and leaf morphology/physiology could explain the observed arthropod abundance and prey capture patterns. Information from this study will aid in the conservation and management of Pinguicula lutea