Marin Master Gardeners
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Marin IJ Articles

Native plants in your garden can boost biodiversity

May 13, 2017
Marie Narlock

Like people, plants live in communities. Most of us select our neighborhoods for similar reasons: good schools, quick commute, nice weather. Plants can’t exactly choose a neighborhood or pack up and move when the going gets rough. They evolved over many years alongside animals, fungi and microbes to form a complex network both above and below ground. They withstood fire, flood, grazing, plowing and building — and they’re dealing with climate change now. They provided sustenance and livelihood to the first Californians and are the foundation of our native ecosystem. Simply put, they provide us with a sense of place and a starting point for the entire food web.

 

Some plant communities are obvious: a walk in Muir Beach’s shady mixed evergreen forest is completely different than a hike through Mount Burdell’s oak woodland or the windswept coastal sage scrub in Inverness. Thanks to our geographic diversity and splendid climate, we Marinites boast an abundance of plant communities, from saltmarshes and vernal pools to pine forests and dry chaparral. On Mount Tamalpais alone, there are five distinct plant communities, some in better shape than others.

California is not unique. Almost every location on Earth has a native plant community that reflects each region’s climate, soil, topography, rainfall and other factors. Today, scientists estimate that around 20 percent of plants are threatened by extinction. That means that of the 6,500 native plants in California, around 1,300 may disappear. This may not seem like a big deal — we’ve got plenty to spare, right? But it could have a profound effect not only on how your neighborhood looks but also on the health of the broader environment.

 

Nine out of 10 leaf-eating insects such as caterpillars can only eat native plants. These insects are critical pollinators for our food supply and they themselves are food for larger animals. They assist with the decomposition process, which helps recharge soil and keeps things growing. They also aid in regulating the population of other organisms, keeping the balance of “good bugs” and “bad bugs” in check.

The ripple effect that occurs in every plant community is silent, yet indispensable. Take that picky eater caterpillar. Without the necessary plants, say goodbye to the caterpillar and then the butterfly, which needs specific plants to lay her eggs. Then say goodbye to the baby birds that can’t find caterpillars to eat. Fewer birds result in gargantuan consequences to agricultural pest control, reforestation and watershed health — benefits estimated to be worth $16 trillion each year worldwide. In the U.S. alone, some bird species populations have declined sharply in the past 40 years; experts estimate a loss of 60 to 90 percent. We need to bring back these winged workers to keep the ecosystem economy moving!

 

What does this mean for you and your backyard? It means you and the plants you select are part of a vital, interconnected community that extends well beyond your house. Like becoming a volunteer firefighter, you can help keep your plant community safe by including just a few native plants in your garden.

Do not discount your impact: native gardens in urban and suburban areas have a measurable benefit on biodiversity. One native oak tree can feed 5,000 beneficial insects, and native plants produce up to 35 times more caterpillars than non-natives. Plus, they’re easy! Native plants are low-maintenance and require zero amendments, fertilizers or pesticides. They are already attuned to your soil, climate, and rainfall. They are typically well-behaved, since they are already co-existing with neighboring plants. And if you love your natural surroundings, it’s a sure bet you’ll like extending that native beauty into your garden.

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