Posts Tagged threats to native wildlife
Wonder Spouse and I have been privileged to live on the same five acres of North Carolina Piedmont for 30 years. When I first saw the land covered in melting snow on a January day in 1989, I knew enough to recognize its potential. A diverse array of mature trees offered clues about soils and microclimates. In my mind’s eye, I could imagine the native species that should be present, and others that would do well if I added them.
Still, my little green haven exceeds my expectations nearly every time I walk it. Something — or someone — new is always appearing, and I believe it is because Wonder Spouse and I have deliberately chosen plants that have filled in some of the missing pieces of native ecosystems that I detected three decades ago. As a friend recently wrote to me, “If you plant it, they will come.”
When some birder friends of ours stopped by last fall and walked our land with us, they said they observed/heard about 60 bird species during the course of our walk. The high number is in part due to the growing beaver-built pond and wetland off our property on the other side of the creek. The raised water levels have attracted all manner of aquatic species of birds, mammals, reptiles, and amphibians. Many of those species occasionally wander over to our side of the creek to explore. I know this for a fact now, thanks to the critter camera that Wonder Spouse gifted me with this past January. We attached it to a tree and aimed it at a path along the creek, where we often see deer tracks. Thanks to the camera, we now know that many species besides deer routinely travel that path.
I realize that most folks aren’t lucky enough to live beside a healthy wetland, but even a quarter-acre lot possesses microclimates created by directional exposure and topographic variations. You can instantly serve more native wildlife guests by providing a small water feature, such as an ornamental pond. We have such a feature at our front entrance. Every year, frogs from the wetland find it, chorus lustily, then deposit gelatinous eggs that become tadpoles that eventually morph into new frogs. Amphibians are always on the lookout for such ponds, because they are usually protected from at least some of their predators, raising the odds of success for tadpoles to become frogs.
On this Earth Day 2019, I encourage all my plant-loving readers to revisit your landscape designs for additional opportunities to provide habitat for native wildlife. Rapid urbanization of the southeastern US Piedmont region is destroying many areas that once sheltered our wildlife. Ecological degradation caused by environmental pollution, invasive non-native species intrusion, and climate change-related weather shifts is causing dramatic reductions in our native wildlife from insects to birds to larger animals. Every human home landscape can make a critical difference to the continuing survival of our native wildlife.
You may not see quite the diversity of species my critter camera has captured on my five acres, but you will notice an uptick in beautiful songbirds if you plant native shrubs that provide food and cover and perhaps add a few nesting boxes and a bird bath or two. Those same shrubs will provide habitat for the caterpillars songbirds use to feed their nestlings. But they won’t eat them all, meaning you’ll see an uptick in butterflies and moths.
Your yard will come to life before your eyes. Your landscape will be vibrantly beautiful and healthy. And you will have the satisfaction of knowing you are doing your small but vital part to keep the blue-green jewel we call Mother Earth alive and healthy.
The only gardening magazine I subscribe to is The American Gardener, the magazine of the American Horticultural Society. It’s a benefit of membership – the only one I use much – and membership is expensive, compared to the annual cost of other gardening magazine subscriptions.
But only this magazine consistently provides articles in which I actually learn new and useful information. It is the only magazine that asks me to think about gardening in a larger context. A case in point is the March/April 2015 issue. Articles range, as usual, from practical concerns (“Designing an Inviting Garden”) to an article addressing the long-range health of our gardens and the native ecosystems in which they grow.
“Coming to Terms with Nativars” by Graham Rice, a well-known garden writer, is an article I wish every gardener would read and take to heart, because it addresses how the choices we gardeners make – even when planting what we think are native species – can affect the well-being of the native wildlife we are trying to support with those planting choices.
As Mr. Rice explains, the term nativar was coined by the well-known plantsman, Allan Armitage, to identify cultivated forms and hybrids of native species. Nativar is a combination of the words native and cultivar. Cultivar is another coined term made from two words – cultivated and variety – and indicates that the plant in question was either deliberately developed by horticulturalists or it was spotted by them in a garden somewhere and named and propagated.
Mr. Rice’s article describes a growing concern among horticulturalists and ecologists about the role nativars are playing – or not playing – in our gardens. This is an ongoing field of research, but it is becoming clear that nativars that vary in appearance significantly from their native species often are much less beneficial to native wildlife. Traits of special concern include:
- Double flowers – Many double-flowered nativars, such as these, do not produce much pollen or seeds, rendering them irrelevant to pollinators and seed eaters. Some doubles produce some pollen, but the changed shape of the flowers makes it nearly impossible for pollinators to reach it.
- Foliage color – The same pigments that give many purple-leaved nativars their leaf color also apparently make those leaves taste bad. Native insects that evolved to eat those species don’t eat the purple-leaved ones, thereby endangering the completion of their lifecycles. Remember that we need those insects to feed our native birds; always the interconnectedness of life must be considered.
- Size and flower color – If these traits diverge widely from the species, wildlife may not utilize such nativars. Bees, for example, are very sensitive to flower color. If a nativar color diverges widely from its parent species, it may not be recognized as a food source by these insects.
How do we know which nativars are good for everyone?
Rice consulted the experts, who suggested that gardeners interested in creating gardens inviting to native wildlife as well as humans should choose nativars that closely resemble the species, but perhaps bloom longer, such as Lonicera sempervirens ‘Major Wheeler.’ Nativars that look like the species but don’t grow as tall, such as some of the dwarf Joe Pye Weed offerings, also remain appealing to wildlife.
Other factors to consider
Rice suggests that we need to consider three other issues when choosing plants for our gardens:
- Propagation techniques used to produce native species and their nativars
- Geographic origins of these propagated species and nativars
- Wild or cultivated origins
The genetics of plants are affected by how they are propagated. Plants grown from locally collected wild seeds will be genetically different from those grown from seeds collected from stock plants in a nursery. These differences may not be apparent to us, but the wildlife that utilizes them for food may not respond in the same way to such plants.
A native species with a wide range – say from Michigan to Texas – will vary genetically, especially at the opposite ends of its range. It makes sense that species selection would favor plants best adapted to the cold of Michigan winters, and that those plants would not fare as well in the heat of Texas summers. Purveyors of wildflower seeds that don’t identify where the seeds were collected (called provenance) are not helping gardeners choose the plants best adapted to their geographic regions.
Wild or Cultivated Origins
Rice says the experts are still trying to decide if nativars propagated from naturally occurring plants in the wild are better for native wildlife than nativars developed by horticulturalists in nurseries. For example is the nativar of aromatic aster, Symphotrichum oblongifolium ‘October Skies’ better because it was developed from a plant found growing wild? The jury is still out.
My Takeway Lesson
Mr. Rice’s article doesn’t much change what I’ve been doing in my yard. I do buy nativars, but I’ve always been drawn to the ones that don’t look that different from the species. Now I have good reasons to continue selecting nativars that closely resemble their parent species.
Given the exponential decrease of worldwide wilderness that I wrote about here, I think any gardener who cares about the health of our dwindling native ecosystems should pass on fancy double flowers in unusual colors and favor the many gorgeous, vigorous nativars that will not only beautify a yard, but also benefit struggling native wildlife. Seems like a no-brainer to this gardener.
My thanks to Graham Rice and The American Gardener for spelling out these issues so clearly for us.