North Star State of Mind
As a researcher I fantasize about what the world would be like if I could stroll up to a field site and have all the species present step out in single-file fashion, nod their beak, snout or what have you, and slowly saunter back into the wilderness.
If this were the case, my Urban Wildlife Institute colleagues and I could cover considerably more sites over a field season and stop worrying about detection probabilities—the likelihood that a species is present and observed.
But, of course, this is not the world we live in. Species can be cryptic, small and/or rare. For example, we’ve only collected one photo of a gray fox—a small canid that can climb trees—over the past three years of our camera trap sampling throughout the greater Chicagoland area.
While it’s unlikely that only one gray fox roams around Chicago, logistical constraints often make it impossible to scour a site to determine species diversity. Instead, ecologists make the best use of their time and set motion-triggered cameras, track plates or a myriad of other wildlife monitoring tools and wait.
And then we wait some more.
This is something I should have kept in mind last winter when Katie Talbott from the BioDiscovery Project at the Minnesota Zoo and I came up with the great idea of comparing species composition at her field site (the Minnesota Zoo in Apple Valley, just south of Minneapolis) and mine (Chicago’s Lincoln Park Zoo).
Both of us were incredibly excited to start this project and quickly forgot that it would take us months to collect enough data to compare. Over last winter the two of us collected wildlife images on our respective zoo grounds by setting four motion-triggered cameras in various locations. One of the coldest and snowiest winters to date certainly created complications (i.e. camera malfunctions, frosty noses and fingers, decreased wildlife activity), but we kept trudging out into the snow to replace batteries, switch memory cards and imagine what may have wandered past the cameras since our last visit.
At the end of our comparative survey Katie and I exchanged data and came across a few similarities and differences. Aside from the animals that travelled in front of the cameras we had thousands of photos of snow dancing in the wind. (Clicking through image after image of slowly shifting snow drifts felt like an avant-garde art experience.) Despite the powdery profusion, we both collected a number of the usual “urban” suspects like gray squirrels, raccoons and coyotes. The Minnesota Zoo, however, has a greater diversity of mammals. Katie collected photos of mink, woodchucks, red foxes and striped skunks—species we commonly survey at field sites outside the urban center of Chicago. At Lincoln Park Zoo we only collected photos of coyotes and raccoons. So what accounts for the difference between the two zoos?
It has to do with location, size and types of habitat available to wildlife. The Minnesota Zoo is located in a much less urban environment, occupies more land (485 acres versus 49 acres) and has extensive expanses of natural area.
Together, this means one major thing for mammals: natural habitat that is more connected. While animals traverse and exist in highly urban areas, many species have a preference for the natural fragments that exist within urbanized landscapes.
Wildlife in Chicago have to deal with higher rates of human density, traffic and impervious surfaces (i.e. roads), all of which can steer them away from urban centers. Yet cities should not be viewed as hapless wastelands, bereft of wildlife, but instead valued for the opportunities they present to conserve the biodiversity of native species.
Lincoln Park, for instance, is home to Illinois’ largest colony of black-crowned night herons, a state-endangered species once thought to avoid urban environments and shy away from people. These birds—and the many other species that make their homes in Chicago—are the reason the Urban Wildlife Institute exists. We strive to better our scientific knowledge of these under-studied species and inform management and planning decisions in urban areas. As the world continues to urbanize it’s critical to understand how to create cities that work for both humans and wildlife.
Katie and I are still splitting up the data we collected this winter. In my next blog post I’ll provide a more thorough breakdown of what was seen where. Until then, enjoy a few of the camera-trap photos we collected!
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The Wildlife Next Door
Camera Trap Slideshow