LE3 .A278 2016

2016

Avery, Trevor
Pick, Frances

Acadia University

Bachelor of Science

Honours

Biology and Chemistry

Biology

City environments are eliminating habitat for many species thereby reducing biodiversity ; wetlands in particular are being threatened. Storm water ponds built in urban areas to collect runoff and prevent flooding can undergo succession over time to develop into quasi-wetlands. This study examined 38 storm water ponds (SWP) relative to five natural (NAT) wetlands in Canada’s National Capital Region to place the SWPs in context as a biodiversity resource in the area. Odonates (dragonflies and damselflies) were used as biological indicators. Odonates are closely associated with vegetation throughout their life cycles, so both odonates and vegetation were surveyed twice during summer 2015. Odonates were sampled in one or more circuits around each pond for a total effort of one hour during peak flight conditions. Vegetation sampling was closely timed with sampling of the odonates, using the interrupted belt transect method. Sampled quadrats were selected based on preliminarily observed maximum diversity. Only circuit 1 odonates were used for analyses, and they were standardized by distance travelled (pond size). There was no statistical difference in the odonate richness between pond types. There was greater vegetation richness at the SWPs, and a higher density of non-native plants in comparison to the NAT wetlands. Odonate richness was unaffected by pond size and age. However, vegetation richness decreased with both pond size and age. There was no significant correlation between standardized odonate richness and vegetation richness. However, the percentage of female odonates ovipositing increased with vegetation richness. SWPs are potentially good sites for management or enhancement to better support the presence of wildlife, helping to replace disappearing urban wetland habitat, while still performing their primary task of holding storm water runoff.

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https://scholar.acadiau.ca/islandora/object/theses:1454