Five Ways to Make Your Yard More Biodiverse

Olive clubtail dragonfly resting on Mountain ash (Sorbus scopulina).


Every 30 seconds in the United States, a football field-sized chunk of natural area disappears due to development, according to research from the Center for American Progress. Most of the natural areas lost in the past two decades were on privately-owned land, which accounts for about 60% of all land in the country. Clearly there’s much work to be done, since only 3% of protected areas in the U.S. are on private land. Currently, only 12% of all U.S. land is protected, which is very bad news for biodiversity. 

Scientists see the goals set by the International Convention on Biological Diversity — protection of a mere 17% of land and 10% of oceans by 2020 — as completely inadequate to handle the Sixth Mass Extinction and the climate crisis. To stop the crumbling of biodiversity — defined as all the organisms on earth, well as the diversity of ecosystems in which they are found, and the genetic diversity within each species — efforts are now behind “30×30”, a global goal to protect 30% of Earth’s land and water by 2030.

President Biden issued an executive order soon after taking office that requires agency leaders to submit input and strategies for how the feds can conserve at least 30% by 2030. Reversing the cuts made by the Trump administration and targeting expansive areas will certainly have the quickest effect, but all important habitat ought to be saved or restored. If you feel hopeless or sickened by the extinction and climate crises made worse by unrestrained development, even a 30 by 30 foot space at home will help. We can’t put it off any longer.

Here are some objectives as you move forward: 

1. Focus on local native plants after removing invasives. There’s nothing terribly wrong with growing a few of your favorite plants—for example, I love certain clematis vines and irises, and I grow organic food to eat. But those plants don’t provide much, if any, benefit for wildlife, so a large portion of the remaining plants I’ve chosen are native species, most of which belong in my area and might grow together in their natural state. Besides being low maintenance (when properly sited), they are absolutely essential to creatures who developed special relationships with them over millennia.

Native species are superior to introduced plants not because they’re trendy or due to some prejudice or because I say so. Simply put, native plants depend on native wildlife and vice versa (when they are in the appropriate place—that is, areas where they evolved together). They’re adapted to local environmental conditions and their value is not based solely as a resource for humans or on appearance (although their beauty is remarkable!).

Plant diversity is strongly associated with species richness, including healthy insect-dominated food webs. As the essential structural and functional base of many of the world’s ecosystems, most insects are “specialists”—they can only survive with certain species of plants that they evolved with (as opposed to “generalist” species that can use many plants). For example, butterflies and moths need certain host plants that provide food for their young, and many native bees forage for pollen only on specific plants at specific times of year. Myriad other insects are able to use only specific native plants; if those plants aren’t around, the insects’ decline or disappearance adversely impacts ecosystems and other animal populations since specialist and generalist insects and other arthropods supply food for other wildlife. Besides habitat destruction and climate chaos, insects are challenged by additional stressors, including insecticides, herbicides, introduced species, and light pollution. To make things worse, stressors often happen simultaneously. A 2019 global review revealed that 40% of insect species could become extinct in the next few decades, with a staggering 2.5% decline in insect biomass per year, and warned of a catastrophic impact on the earth’s ecosystems. In 2020, researchers found that Earth lost more than 25 percent of land-dwelling insects in the past 30 years

Growing natives is an act of compassion for wildlife at our mercy. It helps to think of animals as individuals with emotions and personalities, not just species. Like us, they want to avoid suffering and live a decent life, and most need native plants in order to do so. Animals such as birds and frogs that eat insects directly are of course negatively affected, but other species are as well. Bobcats, for example, are obligate carnivores, but they need native plants since they typically eat animals that consume insects or plant matter. 

Buy plants propagated from source material that originated as close as possible to your site. Using such “local genotypes”  helps ensure that you get plants that are well adapted to your area and preserves the genetic diversity that helps plants (and animals) adapt to changing conditions. Ask growers and nurseries about their sources if you’re unsure.

2. Minimize lawn and be bold when it comes to sizing garden beds. The more space we allocate for native plants, the better. Lawn is an unnatural monoculture that provides almost no support for wildlife, so if it’s not needed, let it go. You can remove it with a sod cutter or spade, but to preserve precious topsoil, cut it short, then cover it with a half dozen layers of overlapping newspaper or a layer of cardboard with holes punched in to ensure drainage. Cover with leaf compost and allow it to break down over many months.

To get ideas for plant selection and how to arrange and space those plants, look to nearby natural areas that support local native plants, inquire with your local native plant society chapter, and check out my book (if you live west of the Cascades). Plant long-lived trees and shrubs for carbon sequestration and habitat, as well as privacy so that unnecessary fencing may be removed, allowing for a contribution to wildlife corridors that connect. Add associated understory plants, including ground covers that offer the best mulch

Speaking of space, growing perennials for pollinators’ sakes means providing at least several plants of the same species that are planted fairly close to each other so that pollinators can easily find them and so there’s enough of a particular flower’s nectar/pollen to go around. But spacing them evenly, in perfect clumps, isn’t necessary and often looks contrived, and lining them up like veggies in a kitchen garden is even worse, aesthetically speaking. Take a walk in a natural area and you’ll find perennials and other plants with an array of spacing—some close together, some further apart; most mingle with other species that they evolved with. Irregular drifts may occur, as if nature took a paintbrush to create rhythmic splashes. Repetition of plant groupings will result in a natural look and more habitat. Be sure to provide at least a couple of species that flower in unbroken sequence from early spring until fall.

3. Avoid pesticides and use organic methods. It’s imperative to not use pesticides (insecticides, herbicides, fungicides, etc.) and chemical fertilizers to prevent harm to beneficial creatures above and below ground at home and prevent toxins from entering waterways and killing downstream. The Environmental Protection Agency has registered more than 18,000 pesticides for use, and more than 2 billion pounds of pesticides are sold every year in the U.S. Pesticides are pervasive in aquatic and terrestrial habitat throughout the country and threaten the survival and recovery of hundreds of federally listed species. They don’t stay put and can kill non-targeted species, decrease biodiversity within soil, are linked to a decline in nitrogen fixation, mess up the complex balance between predator and prey species in food webs, require fossil fuels, and involve heinously cruel experiments on animals. And, the U.N. tells us that about 200,000 people die each year from pesticide exposure. Chemical fertilizers are also very problematic since they kill soil microbes and pollute groundwater and waterways, leading to dead zones, among other damages.

4. Minimize water runoff and maximize carbon storage. There’s much we can do with the water that enters our landscape, and it doesn’t have to take much effort. It may help to think of our yards as mini-watersheds and ask what we can do to make sure the water that leaves our properties is clean and won’t harm other species.

Rain gardens can collect water — from downspouts or hard surfaces where water accumulates — and slow the flow of water, cleaning it as it slowly soaks into the ground and recharges aquifers. Other elements like bioswales, permeable paving, coniferous trees, and even rain barrels can manage water responsibly in our landscapes, reducing runoff that overwhelms storm drains and pollutes waterways. But it’s the plants themselves (along with soil) that effectively filter water and store carbon. Fully and diversely planted gardens — that include long-lived large trees, shrubs and lower plants — are best at cleaning water, preventing runoff, and sequestering carbon; more so than lawn or beds that are mostly wood chips. 

Halictus ligatus on Erigeron speciosus.

Although keeping your soil covered (with plants or mulch) is a good thing for carbon storage, moisture retention and erosion control, always leave some areas with bare soil (fallen leaves and small amounts of light compost are okay), particularly in areas that face south or east. Here’s why:  70% of native bees (such as this “sweat bee,” Halictus ligatus, shown) nest in the ground (the rest raise their young aboveground in cavities, stems, tunnels or crevices). Using thick layers of wood chips, bark dust, or other such substances prevents them from being able to create their nests and if applied after nests are complete, entombs and kills the developing bees.

Also, if you grow veggies, keep tillage to a minimum, if at all. Tilling soil speeds up the decomposition of organic matter, causes erosion, releases carbon dioxide into the air, exposes weed seeds to light, destroys mycorrhizae hyphae, and generally makes soil less fertile. Unnecessary fertilizer will also release more carbon. 

Erosion concerns? Choose native plants with dense, fibrous root systems to control erosion on slopes. In the Pacific Northwest, depending on your location and conditions, consider Douglas-fir, big-leaf maple, vine maple, Oregon white (Garry) oak, madrone, serviceberry, salal,  kinnikinnick, red-twig dogwood, oceanspray, tall Oregon grape and Cascade Oregon grape, western mock orange, red-flowering currant, snowberry, western sword fern, inside-out flower, and many others.

Bushtit nests require moss, spider silk, and other natural substances.

5. Add natural elements and be lazy. Wild species need secure, dry places to spend the winter, pupate, or seek cover during bad weather, and places to raise their young:  (1) Leave the leaves on soil. (2) Include rotting logs and other dead wood in shady spots to supply the perfect home for certain invertebrates and fungi. (3) Introduce brush piles to provide shelter and maybe even nest sites for some birds. (4) If you’ve dug up rocks from your soil, create smooth rock piles or stone walls without mortar to provide cover for wildlife like amphibians and reptiles, as well as arthropods. Making all these elements as large as possible and placing them in quiet areas works best. (5) If you must “clean up,” don’t do it in fall or winter. Instead, wait until late spring and do as little as possible so that those taking cover won’t be disturbed and so that birds can find building materials for their nests, such as moss, lichen, twigs, spider silk, and dried leaves (see bushtit nest, pictured above). If all this sounds messy, it is, but it’s also easy and exactly that characteristic that supports the greatest garden biodiversity! 

Last but not least, give wildlife a drink. All animals — from birds and dragonflies to frogs and salamanders — need water, so include a gently sloping bird bath or more elaborate water feature like a pond, and perhaps a plate full of watery gravel to help creatures thrive. Although the latter is most important during dry weather, birds need water year round to keep their feathers clean and waterproof. Since many urban streams have been buried, wetlands drained, and drought is upon us, it’s the least we can do.

Golden-crowned kinglet and Townsend' warbler.

© 2021 Eileen M. Stark

Earth to Humans: “Wake Up!”

Fifty years ago today, my U.S. senator at the time, Gaylord Nelson, designated April 22 as Earth Day, a day for Americans to speak out about environmental crises. The “conservation governor” of Wisconsin for two terms and U.S. senator for 18 years, Nelson struggled at putting environmental issues in a prominent place in politics, but eventually succeeded. Besides authoring legislation that created a national hiking trails system and the 2,100-mile Appalachian Trail System, he was deeply involved in important bedrock environmental laws including the Wilderness Act, Clean Air Act, Clean Water Acts, Federal Pesticides Act, and National Wild and Scenic Rivers Act.

Although Nelson came up with the idea, it was ordinary citizens — specifically Denis Hayes — who made Earth Day what it was and what it has become, through grassroots political action. The first Earth Day in 1970 was, to date, the largest demonstration of any kind in the country. The goal was an “environment of decency, quality and mutual respect for all other human beings and all other living creatures.” Clearly, he believed in a better future for the planet and all its residents.

Which brings me to the strange times that could become the new ‘normal.’ While it’s very difficult these days not to focus on how the pandemic affects us, climate chaos and widespread exploitation of animals continues unabated. The link between animal and human health is clear; we must remember the other gentler members of the planet with which we are connected—for both their sakes and ours. Although we are just one species on Earth, we have — by far — the biggest impact. 

I’ve always known that wildlife ought to be left alone, to live the natural life that they evolved to live. Wild animals fear us, don’t want us around, and certainly don’t need us. And when we invade and destroy their habitat, the harm that can come to them — and us — is appalling, to say the least. As if we need proof, one study demonstrates that as humans encroach into species-rich habitats — for development, road building, hunting, mining, etc. — biodiversity declines, wild landscapes disappear, and exposure to ‘new’ microbes increases. Many diseases, like Ebola, SARS, HIV, Lyme disease and others, arose that way. Scientists tell us that around 70 percent of emerging infectious diseases in humans are of zoonotic origin, and nearly 1.7 million undiscovered viruses may exist in wildlife.

Our current pandemic is similar to other unknown viruses that have come about under similar circumstances — that is, when humans steal various innocent wild animals from their natural homes and cruelly toss them together in horrendous markets. It’s almost as if the uncontrollable pathogens are responding to human actions that have put harrowing pressure on the natural world, leading to damaging and widespread consequences that put all life — human and non-human animals, and even plants — at risk. Failure to take care of our home and other species’ natural homes also means a failure to take care of ourselves.  

The media has mostly focused on the connection between pandemics and “wet markets” (where miserable live animals are slaughtered and sold). COVID-19 did likely originate in a live animal market in China, but these markets are not the only places that pose dangers, or where animals suffer intensely. Scientists now believe that the current pandemic started as a result of wildlife trafficking and that the disease probably originated in those wonderful pest-eaters — bats — and moved in a live animal market to an intermediary host — possibly the highly endangered pangolin, the most trafficked mammal on earth — and from there the disease jumped to humans. Although some locales have banned the sale of wildlife for food, there are loopholes for alleged medicinal purposes and won’t trafficking just go underground?

Moreover, confining enormous numbers of tortured, domesticated animals close together in factory farms essentially creates breeding grounds for pandemics. Studies have linked factory farming (also one of the largest sources of methane emissions) to more virulent, faster-mutating pathogens. The same animal ag corporations that worsen the climate crisis abet the creation of new, deadlier diseases at high volume that can adapt to humans.

And let’s not forget the indirect destruction, killing and other environmental disasters, such as broken heat records, dying coral reefs, and uncontrollable wildfires. Both climate chaos as well as its causes — rampant development, deforestation, animal agriculture, and other ecosystem destruction — must end, since all force free-living wildlife into contact with people.

As Carl Safina writes, it’s only going to get worse and next time we could face unimaginable “lethal chaos.” But we’re nearly there, when it comes to how we’ve caused crossover contamination to other species. One example: The Siberian (or Amur) tiger, one of the six remaining tiger subspecies and one of the most terribly endangered due to poaching and habitat loss caused by humans, may go extinct soon due to the deadly canine distemper virus (CDV). CVD was first described and likely originated in South America where the closely related Eurasian human measles virus raged in the 1500-1700s. Those epidemics “likely facilitated the establishment of CDV as a canine pathogen, which eventually spread to Europe and beyond.” The virus is suspected to have caused the deaths of thousands of Caspian seals during outbreaks in 1988 and 2000; it nearly exterminated the black-footed ferret, and has decimated Africa’s wild dog populations. CDV hit Serengeti lions in 1994, when the epidemic killed a third of their population — nearly 1,000 animals at once — as well as a huge number of leopards, bat-eared foxes, and hyenas. Additionally, global animal trade spreads the often fatal ranaviruses, which infect amphibians, reptiles and fish, and one reason for the global decline of wild native bees are diseases that spillover from managed, commercial bumble bee or honeybee (Apis mellifera) colonies that suffer from a range of exotic and high-impact pathogens.

The largest mass extinction (since the dinosaurs)
Pandemics may happen more often when climate change is unabated. For example, the Ebola epidemic in West Africa coincided with cutting down forests for agriculture. Bats who lost their homes were forced into new places when their habitat was destroyed. Changing weather patterns also alter vectors and the spread of disease.

According to a new study, as early as the next decade, many more animal species than previously predicted will collapse if greenhouse gas emissions are not lessened, and it won’t be gradual. Nearly all species and all regions will be affected and abrupt collapses in tropical oceans could begin soon. Coral bleaching events have already begun, and collapse of highly diverse tropical forests ecosystems could follow just several decades later. One example that may speed up: As much as half of the planet’s 6,000 amphibian species are in danger of extinction due to a global pandemic caused by wildlife exploitation. Chytridiomycosis, a fungal disease that’s found on every continent except Antarctica, is quickly pushing some species toward oblivion; some, like the Panamanian golden frog are thought to be gone. The disease’s spread can be traced back to the commercial trade in exotic animals and is exacerbated by the climate crisis.

If we don’t learn now, will we ever? We certainly can’t stop every negative aspect of modern human society, but we can proceed in a more gentle, compassionate, sustainable way to reduce our ecological footprint. Not only will it lessen climate change and promote conservation, it will improve our health.

© 2020 Eileen M. Stark