By Lauren Lewis
As the title of this blog implies, our primary focus is: how does an individual garden in the city fit into the bigger picture? And the answer is: there are so many different ways that it’s exhilarating to think about (if you’re nerdy like us!). Arguably the most approachable example of how a garden connects to the world around it is the movement of wildlife in and out of a garden. The vast majority of urban animal species, both invertebrate and vertebrates, are not particularly restricted by fences between gardens, but their viability is hindered by limited green space and limited appropriate vegetation. So that’s where our gardening choices become important. They help determine the presence or absence of wildlife corridors.
Urban wildlife corridors exist at the intersection of urban ecology and movement ecology, which is a very new branch of study in ecology. On a larger physical scale, movement ecology has enjoyed a recent uptick in attention because of executive branch efforts to open up previously-protected US land to natural resource extraction, which creates more barriers to animal movement. The New York Times just highlighted new research showing the extent to which human activity restricts animal movement globally, and also the surprisingly bipartisan efforts to protect migratory paths in the American West. In an urban context the animals are smaller and less attention-grabbing, but gardening in a way that promotes urban wildlife movement can be a small but meaningful action.
A perfect example is CalAcademy biologist Tim Wong (@timtast1c), who learned about the struggling Pipevine Swallowtail butterfly population in SF and took action that has substantially improved the species’ population. The Pipevine Swallowtail caterpillar feeds only on California pipevine, which has become rare in SF, so Tim found the plant and began growing it in his butterfly-friendly garden at home. As the butterflies have thrived there he has brought both the plant and the caterpillars to the California Native garden at the SF Botanical Garden, and the population is growing.
For the rest of us in SF, there’s a wonderful resource for learning and garden planning- the Green Connections Ecology Guides. The city’s Green Connections program will create a bunch of long “paths” through the city over the next decade that are specifically designed to be safe and pleasant for travel by foot or bike. The idea of the program’s Ecology Guides is that if humans can travel along those routes, then appropriate plantings can make them pleasant routes for animals we want to support too. Check if there’s a route near your garden that can help guide some of your planting choices, but even if not, some plant-focused routes, like the Coyote Bush route along Kirkham out to the beach, are very informative about the ecosystems our city was built upon.