By Will Stahl
Environmental issues appear to come in macro and micro versions. The macro issues are the ones that everyone has heard of: global warming, ocean over-fishing and dead zones, antibiotic-resistant bacteria that threaten world-wide pandemic.
The micro issues are the invasive species taking over your local green space, the discharge of chemical pollutants from a nearby industry and the possible arsenic in your well or the radon in your basement.
On Saturday, January 25, I attended an event that in my mind erased the boundaries between macro and micro. The event was the “Toward Harmony with Nature” conference, sponsored by the local chapter of Wild Ones, and organization dedicated to promoting the planting of native plant species in people’s yards. It sounds like a micro issue, and that is how I had always thought of it, but the keynote speaker, Dr. Doug Tallamy turned my thinking more than I would have thought possible.
His speech was titled “Why We Need More Natives in Our Landscapes,” which sounds micro enough, but he proceeded to explain why the changes we have made in the land we live on, the changes we take for granted such as turf lawns and ornamental landscape plants have removed the underpinnings of the ecosystem that we inherited when our forbearers settled this land.
When the settlers from the eastern US and Europe occupied this land, it was filled with species which depended on the native vegetation that grew here. They were not able to adapt to the change in the landscape that occurred when the plants they evolved to live on were replaced by imported crops, parking lots and turf grass lawns.
“Specialization is the rule, not the exception,” Dr. Tallamy said, and he proceeded to describe many examples of how animals we think of as our usual neighbors have requirements we never knew. For example, chickadees, which we think of as seedeaters and see at our bird feeders all the time, require caterpillars to feed their young. A pair of chickadees will deliver food to the nestlings about every three minutes, 390-570 caterpillars a day for 16 to 18 days, about 6 to 9,000 caterpillars. We think of hummingbirds as eating nectar from flowers or syrup from our feeders, but 80% of their diet is insects. Many of our common birds have similar habits, and the lack of plants that support their insect diets has been part of a 50% decline in birds of all types compared with 40 years ago.
Because insects are specialized to live on particular vegetation, and birds are specialized to feed on certain insects, the lack of native vegetation has caused declines of both.
Ninety percent of plant-eating insects eat three or fewer plant species. Ecosystems function locally and replacing the plants that are the base of the local food chain will adversely affect the local biome. Biodiversity, the variety of locally evolved plants and animals, is the foundation of ecosystem success.
Ecosystems provide what are called “ecosystem services,” oxygen, water, plants that retain and clean water and prevent floods. According to Dr. Tallamy, we have degraded 60% of the Earth’s ability to make ecosystem services. Half of all forests are gone and they continue to disappear at the rate of 22,000 acres a day. One third of the carbon in the atmosphere comes from cut trees.
We have in this country four million miles of roads, three hundred thousand miles of power line cuts, many tens of thousands of square miles of lawn.
These sound like macro issues, but they also have a micro dimension. Each of us in our own spaces can replace lost eco services by planting the native species that were the basis of the web of life that was here not that long ago. It will come back if we let it.
In our own space, we can reduce the area we have in lawn––the conventional turf-grass lawn is a biological desert, supporting only itself. Begin transitioning to native plants in landscaping. Allow native plants to grow along roadways and power line easements. These areas are not just corridors for species to move but also places for them to live.
Living here in Wisconsin, we can’t replace the cut-down Amazon rainforest or regrow the desertified regions of sub-Saharan Africa, but we can make our own spaces ones that can sustain the kind of life that grows here around us.
The local Wild Ones organization can point the way toward making your own little piece of the Earth a place that can help to maintain its life.