Green Corridors Begin at Home

“Is the deer crossing the road, or is the road crossing the forest?” 

To survive, most wild fauna must be on the move—to find food, water, safe shelter and breeding sites, mates, and, for some species, to migrate. But wildlife habitat is increasingly destroyed, degraded, or fragmented into small, isolated patches—by human-made barriers such as buildings, fences, lawns, and roads—which intensify their struggle to survive.

Habitat loss is one of the main threats to wildlife. More people and development mean less natural habitat, while inaction on the climate crisis forces animals to relocate. Today, more than ever, habitat connectivity needs to be restored and wild ones’ daily and seasonal movements or migrations protected.

Habitat connectivity is defined as the degree to which the landscape helps or hinders animals’ movements, as well as other ecological processes, such as seed dispersal. Whether they’re called conservation corridors, green corridors, habitat corridors, or wildlife pathways, their purpose is identical: To provide native habitat as seamlessly as possible, so that wildlife populations may be connected instead of separated. Even in deteriorated landscapes, such corridors boost biodiversity, allow genetic exchange between populations, and may even help ease the reestablishment of populations that have been decimated, isolated, or previously extirpated.

Recognizing that every front, back and side yard—even those within urban areas—is part of an intricate ecosystem that could support a great number of species is the first step toward encouraging rich, natural diversity. When “real” or “naturescaped” yards link directly to others like them, they help mitigate some of the effects of fragmentation, a huge threat to biodiversity. In general, urban and suburban areas are highly fragmented. Wildlife corridors are essential, especially for animals with large ranges.

You might be wondering, “Aren’t large-scale habitat connectivity projects happening?” or “Isn’t my yard too small to help much?” Yes, and no: The big projects are vital and projects such as underpasses and overpasses that help wildlife cross busy roads (that kill or injure many millions of animals each year) are multiplying, thanks to recent legislation in some states, as well as the federal Wildlife Crossings Pilot Program that provides funding. But also crucial are all the little spaces that—even if they’re not in the path of pronghorn or monarch butterflies—when added up, create interconnected networks. As I wrote in my book, “To be most beneficial, gardens need to connect—to each other and to the larger world—to provide continuous passage for wildlife and allow each garden to work and blend harmoniously with others nearby. A single naturalistic garden has benefits, but when in proximity to others like it, its worth multiplies.” Studies show that “the role of corridors is crucial for enhancing biodiversity in green spaces such as domestic gardens … results clarify the effectiveness of corridors in urban landscapes and have direct implications for the ecological management of cities.”

What to do? Whether you’re an avid gardener or someone who cares about dwindling wildlife, you can take positive action to help your property, balcony, or communal green spaces act as safe stepping stones within a green corridor that supports wildlife. It’s something that we can do despite (or perhaps because of) the heinous weakening of environmental protections by certain politicians over the past few years. And, it’s effective, rewarding, and usually fairly easy if you plan ahead.

Some basic tips:
Grow a diversity of locally native plants, and be sure to remove exotic invasive plants as much as possible beforehand (incrementally if they are used by wildlife). Your yard doesn’t have to be exclusively native, but when planted appropriately, the trees and shrubs that evolved in your area are especially important for supplying food, shelter, and possibly nesting sites.

Don’t fence them out (or in). When we moved into our house, one of the first things we did outdoors was remove two gates to our backyard. They served no purpose and I wanted to make it easy for four-legged fauna to come and go. While there are situations where fencing is helpful (for a dog run, to protect a veggie garden, or to prevent a little one from wandering off), many urban and suburban back yards are separated by tall, unattractive fencing that does nothing useful except provide some privacy.

Instead of impassible fencing (that also greatly diminishes air circulation around plants and, in the case of wooden fencing, wastes trees), think living, breathing native shrubs—either in an unpruned hedgerow or more naturalistic plantings—to provide privacy. Besides being much more aesthetically pleasing, shrubs alone provide food and shelter for wildlife, shade and carbon sequestration, and contribute greatly to green corridors. Unlike fencing, shrubs provide privacy but allow small animals to pass under, through, or along, from garden to garden. If your yard is tiny and you must add a narrow barrier, consider wooden lattice fencing with large openings, upon which (noninvasive) vines could grow (but don’t do this if you live where megafauna could get caught in it).

Some types of fencing can brutally kill or ensnare wildlife (and even people), often at nighttime. Avoid metal rail fencing, any spiked fencing, and all plastic netting. When not in use, take down volleyball and soccer netting.

Rethink manicured yards. Highly pruned, overly tidy, leafless, lawn-centric yards sustain very little life and are high-maintenance. Instead, create a chemical-free native wildlife garden that is more relaxed (some might say “messy”) and has the ability to support much more life. If you’re worried about what the neighbors will say, add some signs of human intention in the front: (a) Create interesting structure by varying the heights of plants so there is a connection from tall trees to ground cover—this not only looks nice, it’s great for wildlife; (b) Choose shrubs that can grow to their full potential without crowding each other out, hiding your doors or windows, or encroaching into pathways—all of which will eventually require harsh pruning; (c) Instead of one plant here, one plant there, plan for a rhythm by growing perennials in drifts or uneven clusters, and then repeat them elsewhere in your yard (this is also highly beneficial to wildlife like pollinators who need multiple plants to feed on); (d) Consider adding step stone paths, bird baths, strategically placed half-buried rocks, sculpture, or nest boxes (if appropriate), but don’t overdo it—few “focal points” are better than many. Don’t add landscape lighting, which is deleterious to living things.

Avoid “ecological traps” and minimize danger. When we grow native plants, minimize lighting, leave the leaves, add a water source and other positive elements to our yards, one of the wonderful outcomes is the increase in wild visitors. But no matter how well-meaning our actions are, “ecological traps” may be created when we make our yards welcoming to wildlife but don’t address the human-induced hazards that lurk nearby. When we design for biodiversity we must consider not just adding habitat, but also what we might inadvertently set them up for, such as being preyed upon by cats or dogs, or injured or killed by windows or some other hazard in our yard. Of course we don’t want to eliminate windows or companion animals, so we have to embrace adaptations that allow us to keep them and protect wild ones at the same time.

In other posts I’ve addressed the disastrous effect that reflective windows have on birds as well as the consequences of light pollution. Another lethal issue is free-roaming cats. Certainly not all cats are avid hunters, but many are, and it’s up to us to take responsibility for their actions. If you already have a kitty who’s been spending a lot of time outdoors, it’s going to be difficult—or even cruel—to suddenly lock him up and throw away the key. Cats are obligate carnivores, so it’s not their fault that they hunt, or want to. For those with unbreakable habits, consider limiting outdoor adventures during baby bird season (late spring to mid-summer) and at those times of the day when birds are actively feeding (typically early morning and late afternoon), and use hanging birdbaths instead of grounded ones. The next time you adopt a new cat, keep them safely indoors but offer a place to get fresh air, like a catio. Dogs, of course, may also be problematic, especially in areas where sensitive wildlife live or nest on the ground, such as fragile amphibians and reptiles.

Minimize hardscape. Unnatural hardscape does nothing for wildlife. Every time we remove hardscape and replace it with, say, regional native plants, dead wood, a water source and other beneficial elements, we help wildlife thrive. Minimizing it in your yard also helps reduce stormwater pollution, improve water quality, and mitigate the impacts of climate chaos.

Urge urban planners and park space advocates to plant native species. Despite native plants’ benefit to ecosystems and humans, they aren’t often added. A typical city park, for example, contains large expanses of lawn and some isolated trees (often non-native). Ecosystems are much more complex and may include tall trees, smaller trees, large and small shrubs, perennials and grasses, dead wood and fallen leaves, which support a large number of species. Creating native beds surrounding single trees, or at least within designated areas, will add complex layers without eliminating picnic space.

Finally, talk with your neighbors. Imagine if everyone’s yard was connected—botanically speaking—to the one next door, preferably without fences and gates. Then imagine that these connections continue from neighborhood to neighborhood and go on for miles, finally reaching a large natural area that’s even more supportive. Some neighbors may find your ideology beyond their grasp, but others may surprise you. Some people simply may not know about the deadly hazards of development and exotic plants, and speaking with them—or at least setting an example—may help to open their eyes and hearts.


© 2020 Eileen M. Stark

How to Grow Pacific NW Native Plants in Outdoor Containers

Although native plants will always do best in native soil with light, moisture, soil, and associated plants as close as possible to what nature intended, many people have microscopic yard space or just a porch or balcony. With a bit of planning and time, quite a few Pacific Northwest native species can successfully be grown in pots or other containers. Some — like drought tolerant sedums — may also be grown on green roofs.

When trying to figure out which plants might do best in your situation, consider which plants are native to your area. Then, take into account each plant’s needs and its natural environment, not just its physical appearance. For example, if you love maidenhair fern, which generally is a forest dweller that typically grows near streams or misty waterfalls, you know you’re going to need to supply a damp, fairly shady environment with soil rich in organic matter. Conversely, flora that typically grows in tight spaces — like rock crevices — may do well in sunny spots with fast draining soil within pots that aren’t terribly large.

If you’re thinking of grouping plants together in huge containers, remember that in Nature plants aren’t often found growing immediately next to another species, and those that grow quickly may shade out those that don’t. To help along container-mates, give them enough space and choose species that have the same needs (same light, moisture, and soil type) and that would likely grow together in nature (plants known as “associate species”).

Some ideas
For bright situations, try perennials such as yarrow (Achillea millefolium var. occidentalis), blue-eyed grass (Sisyrinchium bellum or S. idahoense), nodding onion (Allium cernuum), monkeyflower (Mimulus spp.), sedum (Sedum spp.), camas (Camassia spp.), or bitterroot (Lewisia columbiana). In very large containers consider hairy manzanita (Arctostaphylos columbiana). The latter two need sharp drainage.

Partly shaded containers might grow Douglas iris (Iris douglasiana), tiger lily (Lilium columbianum), leopard lily (Lilium pardalinum subsp. vollmeri), western columbine (Aquilegia formosa), showy fleabane (Erigeron speciosus), alumroot (Heuchera spp.), or the penstemons that like some shade and moisture (Penstemon serrulatus or P. ovatus). In very large containers, consider shrubs such as mock orange (Philadelphus lewisii), or oceanspray (Holodiscus discolor), but remember to rehome them before they get root-bound.

For shady areas, choose piggyback plant (Tolmiea menziesii), foamflower (Tiarella trifoliata), maidenhair fern (Adiantum spp.), and deer fern (Blechnum spicant), and in very large containers, snowberry (Symphoricarpos albus) or evergreen huckleberry (Vaccinium ovatum).

Keep in mind that any potted plant will need much more attention than those in the ground. Your watchful eye and experience will tell you what works and what doesn’t, but for starters, here are some things to consider to maintain plant health:

~ Choose containers that allow plenty of room for root growth. Ceramic and clay pots are generally best, but keep in mind that clay pots can crack when subjected to excessive water and low temperatures.

~ Be certain your containers have a drainage hole. Never let pots sit in saucers full of water for long periods.

~ Plants that grow fairly deep roots are going to need a deep pot, but width may be just as important. Needless to say, plants with fairly shallow roots will be able to handle shallower pots.

~ Plants that tend to spread a lot, such as wild strawberry and western bleeding heart, may not be happy in a pot for more than a couple of years.

~ Choose a growing medium that suits the plant (preferably without peat as an ingredient). Plants that need moist, rich soil will appreciate the addition of extra compost, while plants that need to dry out between waterings will do best with fast draining soil (add small gravel, sand and/or perlite to facilitate drainage).

~ Group potted plants with similar needs together to make watering easier.

~ Keep plants — even those that like quite a bit of sun — out of scorching sunlight during the hot summer months because pots will dry out very quickly, especially if they’re in clay pots.

~ Arrange larger pots in the center, with smaller pots at the edges, being aware that small pots may need more shade since they dry out more quickly.

~ Repot plants every few years to keep them healthy and growing. Donate those that have outgrown your space to someone with a yard, but try to do it before their roots are fatally confined (“root bound”).

~ Protect plants from freezing temperatures and excessive wind. Potted plants’ roots are subjected to much colder temperatures than those growing in the ground, so during sub-freezing wintertime temps place them in a protected spot or bring them indoors or insulate their roots from damaging cold.

~ Never dig plants from the wild, for two reasons: Usually the plants won’t make it and you’ll end up with a dead plant, and stealing from what’s left of the natural world is unethical. Please purchase plants from reputable nurseries or grow them from seeds that are obtained responsibly.

Heuchera micrantha (‘crevice alumroot’ or ‘small-flowered alumroot’)

© 2020 Eileen M. Stark