NSF/EPSCoR: Ecology and Conservation of an Insect-feeding Guild Involving a State-endagered Carnivorous Plant

Sundews are carnivorous plants that capture and digest insect prey using hundreds of sticky, dew-covered glands protruding from their leaves. They exist on every continent except Antarctica and are often isolated in fragile wetland habitats. In Kentucky, an isolated population of the red sundew (Drosera brevifolia) persists only in a tiny wetland meadow in Pulaski County, far north of the species’ primary range. The species is currently listed as endangered in the state of Kentucky and threatened in the state of Tennessee. Further south the species is more abundant, ranging from Georgia to Florida, and from Virginia to Texas. Red sundews depend upon a minimum level of disturbance to create exposed patches of soil for colonization and to reduce competition from taller plant species for sunlight. Too much disturbance, however, can put the species at risk of local extinction. Recent research has suggested that interactions with animal predators may also play an important role in the species’ ecology. Specifically, spiders are numerically dominant predators that prey on the very same small insects that sundews capture in their sticky traps. Therefore, competition with spiders, both those that build spider webs and those that actively hunt for small insect prey, could potentially affect the feeding success of sundews, their density and distribution, and even their persistence in endangered or threatened communities. Other interactions are possible as well including mutualism, commensalism, or even kleptoparasitism if large free-ranging spiders were to pilpher prey items from the sticky traps of sundews. Effective conservation of red sundews in Kentucky and carnivorous plants in general will require a better understanding of the interactions and disturbance dynamics of such systems. To understand these more fully, we propose an innovative integration of multi-site field sampling, laboratory and greenhouse analysis and experimentation, and mathematical modeling that blends our experience and expertise in the use of these often disparate approaches. The proposed research will improve our understanding of spidersundew interactions and the role disturbance plays at different spatial scales, but will also develop a focal system with which to educate and motivate biology students in Kentucky. All of this should serve to increase our general understanding of ecological communities and help with the conservation of this state-endangered system specifically. The goal is to make carnivorous sundews and their spider competitors into one of the best understood examples of a biological community involving diverse ecological interactions among community members.