Life in Urban Ponds
City ponds are important habitats for many beneficial insects. These insects serve several ecological and ecosystem functions including eating mosquitoes and filtering water. The presence of aquatic animals like mayflies and zooplankton can indicate that the water body contains low levels of contaminants.
The bugsandplankton lab is interested in whether we can use the natural biodiversity of aquatic insects to reduce the population size of nuisance mosquitoes. Adult mosquitoes lay their eggs in or next to ponds and aquatic larvae develop through four instars and one pupal stage before metamorphosing into adults. One way of keeping mosquito populations low is by reducing their numbers during this juvenile aquatic phase. Dragonflies and damselflies are important predators of larval mosquitoes, and zooplankton can reduce mosquito survival by outcompeting them for food. The first step towards understanding whether we can control mosquito populations by fostering healthy and diverse insect populations is to conduct pond surveys throughout the city. The pictures below show some of the ponds we surveyed in the summer of 2023. From left to right / top to bottom: Point Grey Golf Club, Beaver Lake, Jericho Beach Pond
The bugsandplankton lab is interested in whether we can use the natural biodiversity of aquatic insects to reduce the population size of nuisance mosquitoes. Adult mosquitoes lay their eggs in or next to ponds and aquatic larvae develop through four instars and one pupal stage before metamorphosing into adults. One way of keeping mosquito populations low is by reducing their numbers during this juvenile aquatic phase. Dragonflies and damselflies are important predators of larval mosquitoes, and zooplankton can reduce mosquito survival by outcompeting them for food. The first step towards understanding whether we can control mosquito populations by fostering healthy and diverse insect populations is to conduct pond surveys throughout the city. The pictures below show some of the ponds we surveyed in the summer of 2023. From left to right / top to bottom: Point Grey Golf Club, Beaver Lake, Jericho Beach Pond
Preliminary Survey Results
We surveyed Jericho Beach Park (JB), Beaver Lake (BL), the UBC Botanical Gardens (BG), McCleery Golf Course (MC), and Point Grey Golf Course (PG). The ponds at the two golf courses contained the highest abundance and diversity of aquatic invertebrates. The charts below show the different types of insects we found at each site (left/top panel). The right/bottom panel shows the insects grouped by ecological role. Each site was sampled the same way. We pulled a net 1 metre through the water three times at three different locations (edge, open water, near vegetation), for a total of 9 sweeps.
We surveyed Jericho Beach Park (JB), Beaver Lake (BL), the UBC Botanical Gardens (BG), McCleery Golf Course (MC), and Point Grey Golf Course (PG). The ponds at the two golf courses contained the highest abundance and diversity of aquatic invertebrates. The charts below show the different types of insects we found at each site (left/top panel). The right/bottom panel shows the insects grouped by ecological role. Each site was sampled the same way. We pulled a net 1 metre through the water three times at three different locations (edge, open water, near vegetation), for a total of 9 sweeps.
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Some key findings
Mayfly nymphs are quite sensitive to pollutants and we were pleased to see large populations of mayflies in several sites. We also found many damselfly and dragonfly larvae, and other predators like small and medium-sized water striders. In general there was a positive relationship between the overall number of insects we found, and the diversity of the insect community. The blue bar graph shows the number of different aquatic insect species we found in the different sites. The black silhouettes show the larval/nymph stages of damselflies, dragonflies, and mayflies (not to scale). The backswimmer is an adult. The photos below show an adult damselfly, dragonfly and mayfly. |
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What's next
We mentioned above that zooplankton often outcompete mosquito larvae. Last summer we noticed that ponds with many zooplankton contained very few mosquitoes. This year we would like to quantify this relationship in Vancouver ponds as well as run lab experiments testing the potential mechanisms that might drive this asymmetric competition. Stay tuned for a report on what we find this summer! The photos below show a single mosquito larva, a bunch of mosquito pupae (and a few larvae) and Daphnia zooplankton. The mosquito larva is about 1cm long, the pupae are 3-4mm long, and Daphnia are about 2mm from head to tail.
We mentioned above that zooplankton often outcompete mosquito larvae. Last summer we noticed that ponds with many zooplankton contained very few mosquitoes. This year we would like to quantify this relationship in Vancouver ponds as well as run lab experiments testing the potential mechanisms that might drive this asymmetric competition. Stay tuned for a report on what we find this summer! The photos below show a single mosquito larva, a bunch of mosquito pupae (and a few larvae) and Daphnia zooplankton. The mosquito larva is about 1cm long, the pupae are 3-4mm long, and Daphnia are about 2mm from head to tail.
Funding and Acknowledgements
Alexandre Beauchemin did 99% of the work in summer 2023 and was funded by a UBC Faculty of Science Science Undergraduate Research Experience Award and by operating grants to the bugsandplankton lab from the Government of Canada Natural Sciences and Engineering Research Council. We thank the Vancouver Park Board, UBC Botanical Garden, and Point Grey Golf Club for permission to sample aquatic insects. The lab is grateful to work and learn on the traditional, ancestral, and unceded lands of the Musqueam, Squamish, and Tseil-Waututh nations. All photos and graphics were taken/created by Michelle Tseng. The header photo was taken at the UBC Botanical Gardens.
Alexandre Beauchemin did 99% of the work in summer 2023 and was funded by a UBC Faculty of Science Science Undergraduate Research Experience Award and by operating grants to the bugsandplankton lab from the Government of Canada Natural Sciences and Engineering Research Council. We thank the Vancouver Park Board, UBC Botanical Garden, and Point Grey Golf Club for permission to sample aquatic insects. The lab is grateful to work and learn on the traditional, ancestral, and unceded lands of the Musqueam, Squamish, and Tseil-Waututh nations. All photos and graphics were taken/created by Michelle Tseng. The header photo was taken at the UBC Botanical Gardens.