Earth Day has come around again, but how many of us know of its origins? The first Earth Day took place in 1970, and rather than a string of volunteer efforts, festivals, or photo-ops- it was an outright protest. 20 million people gathered in all corners of the US to demand that something be done. The book Silent Spring had been out for almost a decade. There was no Environmental Protection Agency, no Clean Air or Clean Water Act. During demonstrations in Philadelphia, activists reportedly signed a ‘Declaration of Interdependence’, “dramatizing a point that every man depends on his fellows and on nature to help keep the environment livable.” Collective consciousness was moving towards understanding the scope of human impacts on our environment, though the science needed to measure them was still future. Forty-two years and forty-two Earth Days later, perhaps it’s time to reflect on how far we’ve come.

Just before this year’s Earth Day, a press release announced the results of a study that examined the biodiversity of plants in urban areas. The study looked at the traits of plant species in Minneapolis and St. Paul and found that these urban backyard dwellers shared traits and were less genetically diverse than those in habitats not dominated by humans. “The typical spontaneous yard species is short-lived, fast-growing, produces small seeds, uses humans as dispersal vectors, and is adapted to high temperatures,” the study showed. Years earlier, scientists in Germany had uncovered the very same “relatedness” traits present in the urban plant species they surveyed.

In the 2008 report from Germany, it was mentioned that a full 50% of the global population resides in cities or suburbs, (in the US, it is estimated that 82% of our population lives in such areas) and that number is steadily growing. The implications of this are that as urbanization spreads, so may a relatively small genetic pool of plants that as a result will be less equipped to handle impacts to their environments, and will be more susceptible to collapse. Additional concerns are that the plants spread by humans are sometimes invasive, and may not require pollinators for reproduction. German scientist Sonja Knapp is quoted as saying, “If self-pollinating species are supported by urbanization and consequently increase their frequency in the regional species pool, fewer pollinators such as bees or butterflies will be supported.” Furthermore, the increasing encroachment of invasives on natural habitats has been called one of the biggest threats to biodiversity of our time. As to what action is needed, researcher Cavender-Bares of the University of Minnesota had this to say, “These results suggest that urbanites should consider gardening and harboring a higher number of native species.” She is not alone in her conclusion.

One man at the forefront of what could be called a backyard biodiversity movement is Dr. Douglas Tallamy. In his book, Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, he tells us that biodiversity is critical to healthy ecosystems, which in turn are critical to life as we know it. To illustrate, Tallamy asks us to consider New York City for a moment, but this exercise can also be done with your own urban or suburban neighborhood. He reasons that if NYC were to become its own ecosystem, that is, without any connection to the big, wide, bio-diversified world, it would collapse within a week due to the fact that cannot produce its own food, water, or oxygen¹. It is a habitat designed by humans, expressly for humans. Only. As such, NYC relies on the ecosystem services of complex and diverse natural habitats located elsewhere. After looking to NYC as an example, Tallamy issues this warning, “If we convert the rest of the world into an artificial habitat fit for humans and nothing else, New Yorkers, as well as the rest of us, are doomed.”¹ And yet that’s exactly what it seems we are doing.

In 2008 German scientists admonished that given how much we are shaping our world, “nature conservation strategies for urban biodiversity should be developed”. This is where Tallamy’s book comes in. Referring to it as “reconciliation ecology”¹, or the reworking of human-only used spaces to support other forms of life, he lays out with rich detail a guide for planting native flora in an effort to counter the homogeneity that dominates our backyards. Tallamy makes it clear that this isn’t about a gardening aesthetic, “when I talk about biodiversity in suburbia, I am talking about a natural resource that is critical for our long-term persistence in North America.”¹

Bringing Nature Home is, in many ways, both a Declaration of our Interdependence and a manual for a much-needed movement. The movement surrounding the first Earth Day was credited with the creation of the Environmental Protection Agency, The Clean Air Act, and The Clean Water Act. Forty-two years later, we may not have a Biodiversity Act, but it can be an act that we do tomorrow, starting in our own backyards.

Milkweed leaf beetle (c) 2012 Belinda Beetham

Impact facts from Bringing Nature Home as they appear online:

  • 62,500 square miles (45.6 million acres) of land have been converted to suburban lawn in the United States, which means that land more than eight times the size of New Jersey is dedicated to an alien plant.
  • Four million miles of roads have been paved in the U.S., covering 37,879 square miles of land (nearly five times the size of New Jersey).
  • As many as 33,000 species of plants and animals are imperiled in the U.S. — no longer common enough to perform their function in ecosystems.

1. Tallamy, Douglas. Bringing Nature Home: How you can Sustain Wildlife with Native Plants. Second ed. Portland: Timber Press, Inc., 2009. 1-49. Print.


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2 Responses to Reflections on Earth Day, or, Why We Need Native Plants Now

  1. DiAnne Sundberg says:

    It is a lot to think about and share with others!

  2. Lee Tinker Loe says:

    Why must we talk of “backyard” gardens? We have our entire frontyard in flowers and vegetables with 2 kinds of orange trees, a plum tree and a weeping mulberry.
    Hey! It is work! And we have soooo many milkweed plants and monarch butterflies and also other butterflies and bees. But now we have a bad situation with the milkweed!is the beetle you show in the picture good or bad? In the back we have a large garage apt. a cattery (inclosed area to keep the cats from harming the lizards and birds and toads, a cherry laurel and small but growing live oak tree, both already here, a fig, pomegranite, and Meyer lemon tree and, in a very large pot, a Mexican lime tree. our lot is 50 X 125 feet and the house is large so this is all on a relatively small space. Also have a small deck on the back. Anyway, down with grass, up with wonderful, diverse growing things! Lee Loe, Houston, TX