Scott, Ella, Clean Water Institute/Department of Biology, Lycoming College, 1 College Place, Williamsport, PA 17701, scoella@lycoming.edu; Bohlin, Emily R., Clean Water Institute/Department of Biology, Lycoming College, One College Place, Williamsport, PA 17701, bohlin@lycoming.edu; Rieck, Leslie O., Clean Water Institute/Department of Biology, Lycoming College, 1 College Place, Williamsport PA 17701, rieck@lycoming.edu; Kaunert, Matthew, Clean Water Institute/Department of Biology, Lycoming College, 1 College Place, Williamsport, PA 17701, kaunert@lycoming.edu.
The Robert Porter Allen Natural Area (RPANA) is a 227-acre nature preserve in South Williamsport, Pennsylvania. RPANA includes one of the largest floodplain wetlands remaining on the West Branch of the Susquehanna River. The wetland is currently undergoing a restoration project to expand open water and saturated areas, remove non-native vegetation, and plant native vegetation. Wetlands on the property are largely intact, but there is a lack of fine-scale information regarding current wetland plant distribution, the extent of non-native plant species encroachment, aquatic macroinvertebrate richness and composition, and chemical water quality.
This study aims to provide background (pre-restoration) data regarding the biotic and abiotic status of the wetland. During June to September 2024, a total of 99 1m2 plots were constructed on eight transects throughout the wetland. All plants within each plot were identified to species, and their percent cover was estimated. Following PA DEP protocols, aquatic macroinvertebrates were collected from all eight transects using a D-frame kick net. Samples were preserved in 70% ethanol, and taxa were identified to family-level. A handheld water quality meter was used to take field measurements of pH, dissolved oxygen, conductivity, total dissolved solids, and temperature at all transects. A total of 96 vascular plant species were documented, 72 native species (75%) and 24 introduced species (25%). Peltandra virginica (Green Arrow Arum) was the most abundant species, observed in 43 plots on all eight transects with an average cover of 50%, followed by Leersia oryzoides (Rice Cutgrass) recorded in 23 plots on five transects with an average cover of 25%. Lythrum salicaria (Purple Loosestrife) was the most abundant non-native species, observed in 15 plots across six transects at low density (<20% cover).
Thirty-seven aquatic macroinvertebrate taxa were documented. Transect 1 had the highest macroinvertebrate species richness with 26 taxa and Transect 8 had the lowest with 11 taxa. Asellidae, a moderately pollution sensitive isopod, was the most abundant family with 2,779 individuals counted across all 8 transects. Physidae (Bladder snails) was the second most abundant taxon with 324 individuals recorded in seven transects, and they are a pollution tolerant group. Water quality parameters (pH 6.14-7.58; Dissolved oxygen 1.15-4.06 mg/L-1 ; Conductivity 53-479 uS/cm-1; TDS 26-708 ppm) were mostly within normal ranges for a freshwater marsh. Dissolved oxygen was notably low, averaging 1.7 mg/l. This hypoxic condition may be due to multiple variables including the low flow and lack of connectivity through the wetland as well as the lack of rainfall and hot summer months when measurements were taken.
The dominant vegetation are native species that provide wildlife habitat, food sources, and sediment control. The proximity of native wetland plants to the newly restored wetland areas is a promising sign that colonization of desired vegetation will be successful. This survey will inform invasive plant management plans to eradicate noxious weeds like Purple Loosestrife. The high species richness of macroinvertebrates and good water quality are also encouraging signs that restoration efforts will be successful.
Wetland restoration, Wetland vegetation, Macroinvertebrates, Water quality