Eco-systems in our hands

By Sally Cunningham (for the Buffalo News, March 2018, after the WNY appearance of Dr. Douglas Tallamy, hosted by the WNY Land Conservancy and Erie County Master Gardeners)
{Dr. Tallamy presented to an audience of—mostly—the believers: people who understand the importance of habitat protection. These are some notes from that talk, to reach everyone else.}
First, the basics:
There is very little nature left.
More than 94% of people live in cities or suburbs. About 84% of the land East of the Mississippi is privately owned (with similar numbers in the other half of the country). A large percentage of so-called open space is in agriculture, used for mono-crops (corn, soybeans) or grazing, where biodiversity is scant. Huge acreage is paved for highways, malls, sports or other non-residential purposes. Much so-called greenspace is mostly turfgrass, used for running, biking, or other human activity, and it has little or no ecological value. Where we have anything resembling natural habitat, as in parks and rural property, it is fragmented with so little connectivity that genetic diversity is disappearing. Many species require specific expanses of acreage for survival.
Bio-diversity, as in a rainforest, is the secret to survival of life on the planet as we have known it. But we humans have altered or degraded at least 60% of the earth’s eco-systems.
Where then do we go from here? As scientists, leaders, gardeners, or just caring citizens, what can we do to achieve the least of the worst possible outcomes? We can’t go back to Longfellow’s “forest primeval” (and most people wouldn’t want to), but we can make positive choices at home. And remember that private citizens own most of the land: Our yards must become the habitats that support or at least replace some eco-systems.
Bio-diversity and native plants
When I wrote Great Garden Companions (Rodale Books) twenty years ago, I was promoting the idea that diversity is the key to a healthy organic garden. If you avoid mono-cropping, and plant vegetables together with herbs and flowers in certain combinations, you will attract and keep beneficial insects around (and birds, frogs, amphibians etc.) The community of predators and prey will handle most pest problems. Mixed, diverse planting covers the ground, supports pollinators, and thwarts weeds. Building healthy soil and banning pesticides were/are the other tenets of the system. Such “companion gardens” are a microcosm of what happens in nature—to a point.
Then came the invasive species threat. Soil and Water Conservation leaders, forest biologists, Cornell educators and others were actively teaching that non-native invasive species were out-competing native species (plants and animals) and destroying habitat. Why? Because away from their own lands (where they are eaten) some plants can thrive and spread rampantly here—where they have no natural enemies (nothing that eats them). 
Statistics are overwhelming, but the loss of habitat, the spread of invasive species, exacerbated by climate change, are causing species extinction at 1000 times the natural rate. (Data: U.N. Convention on Biological Diversity 2010). More than 450 species of North American birds are at risk of extinction; we have 1.5 billion fewer breeding birds than forty years ago; the lists go on. (Read: State of the Birds, 2016)
Understanding this, naturalists and horticulturists passionately promoted native plants, opposed non-native invasive plants, and pressed for bio-diversity in our fields, forests, and yards. We argued that native plants belong here, and generally do well in the soil and climate where they originated. We were right to press for native plants, but we didn’t yet have tools to make the strongest case.
Enter Doctor Tallamy
It is rare for great numbers of gardeners, educators, and experts to proclaim in unison that one guy turned their heads around, but a mild-mannered professor of entomology (University of Delaware) certainly did so. WNY Land Conservancy’s Nancy Smith, wildflower lecturer Lyn Chimera, and I are examples of many who changed our teaching and goals based on his book, Bringing Nature Home (Timber Press). {Recently Dr. Tallamy has published Nature’s Best Hope.}

This is the lesson in its simplest form: Insects are the foundation of the web of life. Many of our native insects (that feed the fish, birds, amphibians) are leaf-eaters (or they eat leaf-eaters). What leaves can they eat? Insect herbivores must have the plants with which they co-evolved over millions of years.
Without insects, eco-systems collapse. Native insects must have native plants!
So now we know: Bio-diversity is not enough. We want diverse plantings--but we must use native species. Even if it’s just a portion of every property, let’s add as many natives (and lots of other pollinator plants) in our flower-filled yards in Buffalo, and around our suburban and country homes. Let us also support organizations such as the WNY Land Conservancy that invest in habitat restoration projects such as the Niagara Gorge Restoration and the Stella Niagara Preserve.
Not all native plants are equal
We learned another important truth: Some plants, called keystone plants are far superior for the eco-system services they offer. Tallamy and his entomology students count and analyze the specialized relationships between insects, birds, and plants, as in this example.
Chickadee case study
Like 96% of terrestrial birds, chickadees rear their young on insects. The insects that baby birds can eat are caterpillars—soft and digestible. The Carolina chickadee requires 5000 or 6000 caterpillars to rear a clutch of three babies for about sixteen days. One pair of birds delivered a caterpillar every three minutes (including seventeen species of insects). Other counts showed the parents flying in with 400 to 570 caterpillars daily.
And where are the caterpillars? They’re on native trees (where you’ll never notice them), such as white oaks, wild cherries, willows, and birches. They must be nearby, or the exhausted parents won’t find the food. Choose these trees and help the birds. {In one study, students counted 2 caterpillars on a mature gingko tree; a native oak nearby held 450 caterpillars.}
 The chickadees are just one little representative group, just as monarch butterflies are symbols of hundreds of other important, endangered species. The human footprint has made most “nature” unsustainable unless we actively assist.
The message is weighty. Scientists are not here to spare us unpleasant truths. But we know what we have to do: Plant the right native plants in suitable sites—as often as possible.