Invasive insects continue to have a serious negative impact on our ecosystems. The hemlock woolly adelgid (HWA) is one of the species that is threatening our area in upstate New York as it is spreading at a rate of about 25 km per year on the eastern coast of the US. HWA extracts carbohydrates from the hemlock’s cells causing a slow death, usually about 4-5 years. Most of the studies have been conducted on the biological and ecological impacts of this species and less has been done to understand its chemical impact on soils, and on soil and surface waters. The goal of this study is to determine the effects of HWA induced hemlock productivity decline and death on nutrient content of the soil, and then correlate these results with surface and soil water results to determine how these nutrients mobilize in the infected hemlock ecosystems. Two parks, the uninfected Robert V. Riddell and the infected Mine Kill State Parks in central NY, were chosen for this study. Three sites were selected within Mine Kill State Park; uninfected, infected and untreated, and infected and treated. One site was chosen in Robert V. Riddell State Park. Soil samples were collected using soil cores and pits at each site in three replicates. Soils were separated by horizons and analyzed for soil pH, moisture and organic carbon contents. Extractable nitrate, phosphate and sulfate concentrations were determined by using UV-vis spectrometry. At each site, the top horizon has the highest concentrations of both sulfate and phosphate that decrease below detection limit in the lower horizons. The highest sulfate and phosphate concentrations, 22.5 and 20 mg/L, respectively, are found in Robert V. Riddell State Park. At Mine Kill, the uninfected site has 6.6 mg/L phosphate and 21.2 mg/L sulfate, while the two infected sites only have 2.4 mg/L phosphate and 9 to 14 mg/L sulfate. The pH of the soils ranges between 3 and 5. Soil moisture and organic carbon content decreases from top to bottom in each soil profile. In soil and surface waters, sulfate (6 mg/L) and chloride (0.5 mg/L) are the dominant anions while nitrate and phosphate are below detection limit. Soil waters contain 6-7 times more total dissolved solids than the surface waters, both within neutral pH range. Data of the uninfected sites provide baseline conditions, and all data will be further analyzed to understand how the decreased productivity and death of hemlock can affect nutrient mobility in HWA infected ecosystems.

Effects of woolly adelgid induced hemlock productivity decline on soil nutrient content

249th National Meeting (2015)

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