Biodiversity is essential to humans. As has been well-documented, bio-diversity is under incredible assault. Among other things, bird populations are dropping dramatically, an indicator that the entire food web is in trouble.

Suburbia’s contribution to the problem is the introduction and cultivation of non-native species. Your lawn and ornamental plantings may look green, but they aren’t much better than asphalt for supporting the local food web, because they don’t support bird food. I learned this last night at the Newton Conservators annual meeting. (Horn-tooting side note: I was there to receive an award from the Conservators.)

Professor Douglas W. Tallamy, the guest speaker at the confab, gave a fascinating and frankly inspiring presentation explaining that local caterpillars and other Lepidoptera are well adapted to eating local plant species. All plants have evolutionary adaptations that make them generally toxic. Local Lepidoptera have evolutionary adaptions that allow them to eat the local plant species. Without local plant species, no Lepidoptera. Without Lepidoptera, nothing for birds (and other animals) to eat. Without something to eat, no birds. Without birds, …

Professor Tallamy introduced and explained the concept of the carrying capacity of various plant species. Some species, oak is #1, support an order of magnitude more Lepidoptera than others. Non-local species have next to no carrying capacity. Lawns have little more carrying capacity than asphalt. If we increase the carrying capacity of our local vegetation, we increase biodiversity. We need more and better plants.

It’s high time to reduce the amount of ornamental* lawn in Newton and reintroduce native species.

*If you are inclined to comment that I want to get rid of all grass fields or that I’m a child-hater, please note the use of the word “ornamental.” We need grass for playing fields, for walking and playing areas on our properties. But, we don’t need as much. And, we need to use more shared grassy areas to meet the need.