Date of Award
Acidification in ecosystems, such as water bodies of the northeastern United States, causes significant changes in their biological communities. Changes in lower trophic levels significantly affect the structure and function of higher trophic levels. Benthic macroinvertebrates are useful when examining the effects of acidification because different species are tolerant or sensitive to particular conditions and can act as indicators of water quality. Macrophyte diversity is another explanatory variable influencing macroinvertebrates. Many studies have examined macroinvertebrate assemblages in streams related to water quality, but macroinvertebrates in lakes are less well studied. We compared the benthic macroinvertebrate assemblages in four Adirondack lakes with differing pH. We predicted that as pH decreased, the abundance and diversity of the macroinvertebrates would decline. To test this, we measured pH and collected 40 benthic samples from four Adirondack lakes using a PONAR samler. Macroinvertebrates were sorted, identified to the lowest possible taxon (generally family or genus) and tallied. Macrophytes were identified and diversity was estimated with the Shannon Diversity Index. Benthic macroinvertebrate richness decreased with lower pH (p = 0.03) and increased with greater macrophyte diversity (p =0.02). However, total macroinvertebrate abundance was not statistically correlated with pH (p = 0.08) or macrophyte diversity (p = 0.07). Diversity is often considered a strong indicator of ecosystem health, thus our results suggest that further reduction of acidification may restore diversity of lower trophic levels in Adirondack lakes and improve their ecological conditions.
Gaskill, Jacob A., "Examining the Effects of pH and Macrophyte Diversity on Benthic Macroinvertebrate Assemblages in Adirondack Lakes" (2014). Honors Theses. 35.