Podostemum ceratophyllum “Hornleaf riverweed”, henceforth referred to as Podostemum, is a foundation species in Appalachian rivers. Podostemum provides salient benefits to the benthic community and is one of the only macrophytes inhabiting swiftwater mid-order rivers. Across much of the mid-Atlantic region, Podostemum appears to have been extirpated or severely reduced in abundance. Specific reasons for the species decline include sedimentation, altered water chemistry and pollutants, dewatering, and flow alteration.
We sought to evaluate the effects of Podostemum reintroduction by focusing on the influence of the plant on macroinvertebrate communities. We deployed artificial plants with stem lengths of 5cm, 15cm, and a control (bare rock) for ~8 weeks into multiple Appalachian streams. We hypothesized that increased stem length of the plant would increase total macroinvertebrate abundance, diversity, and change the proportion of the functional feeding groups (FFG) present.
Preliminary data indicates that artificial 5cm stem length plants contain ~300% more macroinvertebrates than controls, and artificial 15cm stem length plants contain ~600% more macroinvertebrates than controls. Additionally, preliminary data indicated a shift in FFG in the artificial plant, with collector-gatherers becoming more abundant. This study will provide novel insight into the structural benefits that Podostemum reintroduction could have in rivers where the plant has been extirpated.