One of the most profound ideas I ever encountered, one that changed my gardening practices for good, is the concept of “species-area relationship.” It boils down to two rules: all living species need a certain amount of territory in which to flourish, to sustain healthy populations; and the larger the territory, the greater the bio-diversity, that is, the more different kinds of species can sustain healthy populations.
The problem for other species in the U.S. is Homo sapiens; according to biologists such as Dr. Douglas Tallamy, author of Bringing Nature Home, some 95 percent of the North American continent is human impacted by all the necessary accoutrements of our culture—cities, suburbs, roads, industrial agriculture—and landscaping and gardens. The result? Many once common species are in decline—not enough room or food. This is bad for us, too. We depend on a functioning ecosystem to maintain the health of our own species in intricate, complex ways scientists are only beginning to understand.
Unfortunately, the natural areas set aside for conservation and restoration, seemingly vast as they are, are not enough to maintain biodiversity; but gardeners can and do play a vital role to help. Humans may have property law and fences. We may think we “own” our backyards and corporate campuses—but nature doesn’t have boundaries. When we treat our gardens as though separate from the surrounding ecosystem, when we plant only non-native trees, bushes and flowers and use gardening practices that imitate industrial farming techniques, we actively decrease the area available to other species on whom we depend. We harm ourselves as well. Conversely, when we garden mindfully, we benefit all species, including ourselves.
Thus I say to all gardeners and landscapers: Practice what Dr. Michael Rosenzweig, author of Win-Win Ecology, calls “reconciliation ecology.” Knit your garden, or whatever piece of land you maintain, back into your ecosystem. Stop using synthetic fertilizer, herbicides and pesticides. If you are putting in bushes, choose native species such as Viburnums. When planting a maple, go native, not Norway. Stop trying to grow grass in shady areas and instead put in low-growing native wildflowers and groundcovers such as native ginger. Choose natives for your perennial beds. Make compost and use it.
While you are doing this, get your neighbors to do the same. Backyard by backyard we’ll all be helping to improve species-area relationship trends while improving our own relationships with other species. We won’t be creating a new wilderness, but we’ll be helping many species flourish, including our own. The birds, bees and butterflies we all love will thank us by visiting and living in our gardens.
Attracting Native Pollinators: The Xerces Society Guide
Strengthening the Biotic Community