Thursday, August 1, 2013

How Much Biodiversity Do We Need in Suburbia?

Knockout Roses have conquered suburban landscapes like this one. I have never seen a bee visiting a Knockout Rose - either in a photo or in real life. (Photo by mellowynk)

Douglas Tallamy thinks we need more biodiversity in our backyards (and presumably in our front yards too).

After taking a walk this weekend through my neighborhood and seeing the same 10-20 plants repeated ad nauseum (boxwoods, knockout roses and daylilies - oh my!), I'm inclined to agree.

Why does biodiversity or the lack thereof matter in the Grand Scheme of Things?

Tallamy makes the case that humans have taken over the vast majority of the land mass in the United States either for housing/retail/manufacturing or for agriculture.

To the extent that we then plant the land we've expropriated with grass and a smattering of (often exotic) plants that are useless to the native fauna, he argues that we are pushing many species toward extinction and thus impoverishing the planet.

Does the average suburban home landscape have any more wildlife value than a plastic tree? Note that plastic trees do not need to be watered or sprayed with pesticides. (Photo by BrickArt!san)

On my 90-minute early morning walk through my neighborhood last weekend, once I left my property, I saw exactly:

- 1 bee
- 2 species of birds (lots of mockingbirds, one goldfinch)
- 2 butterflies
- 1 coyote pup (very exciting!)

Do the yards in your neighborhood have enough biodiversity?

And how much is "enough" anyway? 

Should we set a goal that the average suburban property should contain 20 species of plants? 50 species? 100 species? What is the typical biodiversity of plant species on a 1/4-acre or a 1/2-acre of land anyway?

I don't the answers to all these questions, but I do think they are important questions to ask as gardeners in a nation where the population of humans continues to grow north of 300 million souls.