Open Collections

Robinson-Leith, Emilie; Gooding, Grace; Peng, Shaoxuan; Ladki, Lana; Ni, Luke

In response to the significant population decline of avian aerial insectivores in North America, we collaborated with Birds Canada to investigate trends in both aerial insectivores and their insect prey near the Iona Island Wastewater Treatment Plant (IIWWTP). The IIWWTP is located in Richmond, BC and is one of five wastewater treatment plants serving the Vancouver area. It is situated near the habitats of many aerial insectivore species and is near a stopover for millions of birds as they migrate along the Pacific Flyway. In 2022, Metro Vancouver approved plans to continue the expansion of the IIWWTP. In this study, insect biomass data were analyzed to investigate short-term seasonal changes in the insect community at two study sites (high-vegetation and low-vegetation) near the IIWWTP. Insect biomass was compared to precipitation, temperature, and vegetation level to assess for a correlation. Using eBird community science observation data, we investigated long-term trends in aerial insectivore populations in Iona Region (IR) and the Greater Metro Vancouver Area (GMVA). Daily average recorded individuals per checklist (RIC) was used as an indicator for aerial insectivore abundance. Linear regressions were performed on three bird species’ daily average RIC and insect biomass to test for a relationship between specific aerial insectivore species and their insect prey. Significantly higher insect biomass was found at the high-vegetation site near the IWWTP. Total collected insect biomass and precipitation were significantly negatively correlated across all nine bird groups, while total collected insect biomass and temperature were only significantly positively correlated in two. There were no significant declines in aerial insectivore populations near the IIWWTP from 2004-2023 suggesting that aerial insectivores in Vancouver, BC are not facing the same steep declines as populations elsewhere. There was an observed correlation between insects and aerial insectivores, suggesting a significant predator-prey relationship. Additionally, there was a statistically significant correlation between beetle (Coleoptera) biomass and Barn Swallows (Hirundo rustica). These results suggest that minimizing the disruption of insect communities during the IIWWTP expansion through maintenance of vegetation and aquatic habitats will help ensure the continued protection of the local avian population.

Text

University of British Columbia. ENVR 400

Vancouver : University of British Columbia Library

10.14288/1.0442112

Science, Faculty of; Earth, Ocean and Atmospheric Sciences, Department of

Undergraduate

DSpace