Influence of Canopy Density on Macroinvertebrate Assemblages & Algae Biomass in an Eastern Hemlock Forest

Authors: Rachel Davis, Andrew Gascho-Landis

SUNY Campus: SUNY Cobleskill

Presentation Type: Poster

Location: Old Union Hall

Presentation #: 45

Timeslot: Session B 10:15-11:15 AM

Abstract: Increasing threat of Eastern Hemlock (Tsuga candensis) mortality from the invasion of Hemlock Wooly adelgid (Adelges tsugae) is predicted to affect water quality parameters within headwater stream systems. We conducted macroinvertebrate and benthic algae samples in a hemlock-dominated forest stream in Whitaker Swamp State Forest, NY. The objective of this study was to compare macroinvertebrate and algae biomass samples along the variances of canopy densities within the system. Twelve macroinvertebrate samples were collected in June and August 2024, and algae sampling took place in September 2024. Ephemeroptera, Plecoptera, and Trichoptera orders were of interest as indicators of good water quality. Canopy density didn’t significantly affect macroinvertebrate richness, but algae biomass increased as canopy density decreased. Algae growth correlated with more macroinvertebrates, suggesting that Eastern Hemlock mortality may boost populations due to abundant algae food source. Functional Feeding Groups (FFGs) showed higher increases in predators (PRD), collector-filterers (C-F), and scrapers (SCR). This went against our original hypothesis which we believed SCR would have the highest increase due to their feeding habits with algae. Further research is needed to assess how Eastern Hemlock mortality will affect headwater streams in the Northeastern U.S.