As urban and suburban areas fling their tentacles out further and further, habitat needs for wildlife become increasingly pressing. Some species adapt well to the change; deer and raccoons, for example, are quite happy wandering through residential neighbourhoods and appreciate the ample food supplies available for their delectation. Other species are more fragile, more sensitive to human intrusion, and their ranges shrink in response to development. The solution, in many communities, is the designation of spaces set aside as wildlife habitats, but how useful are these conservation measures?
Do they actually benefit the environment and create safe, usable spaces for wildlife? Or are they mainly tokens that make people feel better about their lives and their choices? How often do conservationists have to strike a hard bargain to get some kind of habitat, anything at all, in the face of development, to preserve something rather than giving up and leaving wildlife with nothing?
Contiguous habitat and what are known as connecting corridors are critical for biodiversity and the survival of more fragile species. Unfortunately, the course of residential and industrial development in human communities has created, in effect, a series of habitat islands, rather than contiguous environments for plant and animal species. Some of these even appear, at first glance, to be diverse; indeed, some planned communities actively advertise their closeness to nature with images of their habitat islands, complete with some nice looking trees and perhaps an artfully posed deer or two glowing in the sunset or nibbling on grass in the morning mist. Residents can feel good about being ‘connected to nature’ while living in their tract homes. They can even pay extra for a picture window to watch the raccoons loot their neighbours’ garbage cans.
Habitat islands, though, pose a number of problems. One is that they tend primarily to house hardier species. Deer, yes, because deer can live anywhere. Other animals, not so much. Likewise with plants. These islands can also become host to invasive species that may quickly outcompete native plants and animals to take over. At first glance, these species may look just as ‘wild.’ Seeing a stand of eucalyptus trees, for example, a person in California might be led to think that it’s so pleasant to live close to nature, with trees all around. As non-natives, though, they push out native oak, redwood, myrtle, and other tree species. Larger animal species with big ranges also do poorly in limited areas, and thus may vanish entirely.
There’s also limited genetic diversity on a habitat island, in part because of a phenomenon called ecosystem decay, where the residents of a habitat island dwindle into a new equilibrium point sustainable for their environment. Furthermore, if plants and animals are essentially marooned, it’s hard to exchange genetic material, which is not a good thing. Hence the rising awareness of the need for connecting corridors. If isolated habitats are going to be created, they need to be linked in some way for the benefit of their residents, to give them a fighting chance at spreading their genes elsewhere and not developing small communities that are too tightly interrelated. Connecting corridors can also be beneficial for animal safety in areas where residents of a habitat island would be forced to cross freeways or other dangerous environments to get to a different habitat.
But contiguousness is still important, even with these habitat corridors. An isolated wetland with a small trail to another wetland has a very different look and feel than a large, contiguous wetland rich with biodiversity and complexity that has taken thousands of years to build up. Habitat fragmentation is an increasingly serious issue as humans nibble into formerly unoccupied areas, sometimes in a highly irregular fashion that exacerbates the habitat splits. Pressure on natural environments all over the world is on the rise and conservation cannot always meet the need, for a variety of reasons.
Advocates for large, contiguous habitats argue that it is critically necessary for the preservation of biodiversity and the promotion of native species. Critics suggest that some conservation is better than none, and demanding large reserves may lead to a backlash effect where no reserves are created because an area lacks space or residents do not support the decision to set aside a large area of land. Here in the United States the National Parks were once one of our great gems, the focus on conservation of nature a point of pride, and now they are viewed as economic vehicles, usable for logging, mining, and other industrial activities even though these may disrupt nature and disturb humans who want to use those areas as well.
Especially when the depredation of natural areas is for housing, it is especially frustrating. Density is not a high priority in much of the United States because of the historic empty space in this country. With the exception of areas like New York City, there was almost always room to expand outwards, and this became the construction norm. People started to value more isolated living, large lots, single family homes, and thus resist the development of density and the encouragement of urban density as a tradeoff for untouched natural space. It would be more efficient to live in tightly clustered communities, but this is not the standard of living we are accustomed to[1. I say, writing in my living room on a two acre parcel and very much enjoying my unshared walls and view of the woods instead of the home of a neighbour.].
Tensions between various competing uses for land have been an ongoing problem that will only grow worse with growing populations and their demands. Situations like this highlight the difficulties of balancing human and animal needs, where the right choice for one party may not be acceptable, or viable, for the other. Promotion of conservation and environmental sustainability requires asking people to make some unpleasant choices; environmental welfare and the right thing may be buying an apartment in the city, not a tract home next to a nature preserve.