With funding from UBC’s Ocean Leaders program and the City of Vancouver, Forrest and Craig used bats as an exemplary group to identify existing supportive ecosystems (bat “hotspots”), areas that could or currently connect those ecosystems, and interventions which might help contribute to both.
Read the full report here.
Urbanization is one of the key drivers of biodiversity loss, and urban residents increasingly lack access to green spaces in growing and densifying cities. The City of Vancouver aims to address these concerns by embedding nature and its benefits in their planning, making space for urban nature, and providing greater access to nature for all residents. To inform and achieve this type of planning, the City worked with Forrest and Craig to identify, rehabilitate, and connect ecological bat “hotspots” in Vancouver.
Bats represent an often overlooked but important indicator species for ecosystem health and biodiversity. They depend on healthy insect populations, cleanfreshwater, and roosting habitats, and so their populations reflect the health of the these factors. Moreover, bats directly benefit urban residents by controlling vectors for disease and agricultural pest insects.
However, little is known about the ways that bats exploit novel urban habitats and how bat communities change as a result of urbanization. This is especially true in Vancouver, BC, where few bat surveys have been done, and none, to Forrest and Craig’s knowledge, have been conducted throughout residential, commercial, industrial, and other non-forest or park habitats prior to this study. In this report, they surveyed for bats throughout the cities of Vancouver and Richmond, BC using a novel acoustic bicycle transect method: Craig, then an M.Sc. at IRES, biked throughout the city and detected bats with recording device.
They then statistically modeled the relationship of bat detections with urban landscape and environmental variables across two bat functional groups (see glossary) to 1) understand how they respond to urban land uses and 2) infer and recommend interventions that may enable a greater diversity and abundance of bats in the city.
Results
- At least 10 species of bats occur in Vancouver and Richmond, BC
- The most abundant species are generalists (e.g., little brown and big brown bats)
- Forested green spaces and freshwater bodies capable of supporting high insect densities likely host the greatest abundance and diversity of bats
- Active and passive human activity, including traffic and other sources of noise and light, likely exclude bats from some otherwise viable habitats
- Surprisingly, low-frequency bats were found to be positively associated with industrial areas
- The diversity of habitats in the region (including forested parks, open parks, ponds, lakes, wetlands, houses, bridges, and other potential bat roosts) likely contributes to the relatively high diversity of species found here
Figure 4. Map depicting model predictions of the likelihood of bat detection across the Metro
Vancouver area. Light colors indicate high likelihood of detection, dark indicates low likelihood.
The light blue translucent layer depicts rivers and sea. Land area falls within those boundaries,
except for the eastern edge.
Recommendations to support bat abundance and diversity
- Create or improve the quality of forest, forest clearings and edge habitats (e.g., savannah or meadow-like areas adjacent forests)
- Create or improve the quality of freshwater bodies and surrounding vegetation to help bats drink water and eat insects
- Maintain or create roosting habitat (e.g., mature trees, old buildings)
- Reduce light and noise in preferred bat habitats (e.g., near freshwater, near dense, diverse, and tall vegetation)