Now that we know what a wildscape is, the question arises: why should we wildscape? That is, is there really good reason to change our landscaping habits?
This is a legitimate question that deserves a thorough answer (thus, the longer post!). Although my answer focuses on pollinators, much of what I say applies to insects generally, and thus to the wildlife that depends on them.
WHY WE NEED POLLINATORS
Pollinators and other insects provide billions of dollars of eco-services annually in the U.S. alone. I describe just two of those services here.
- Many plants can’t survive without them. Research shows that as many as 75% to 95% of the world’s flowering plants need animal pollinators to reproduce. Plants (including flowering plants) benefit the ecosystem in many ways: cleaning our air by converting carbon dioxide into oxygen, helping prevent erosion, and sequestering water and carbon, to name a few. Without pollinators, flowering plants and the benefits they bring are in jeopardy. Additionally, about 2/3 of world’s food crops need pollinators. This translates into about 1/3 of the food that we eat. Looking at it another way, pollinators provide several billion dollars of agricultural pollination services per year. So without pollinators, our agricultural industry would also be in serious trouble.
- Other animals need them for their food. If pollinators are scarce, flowering plants could also diminish, leading to fewer nectar and pollen sources for future generations of pollinators. Additionally, mammals and birds eat the seeds and fruits derived from insect pollination. So fewer pollinators could translate into fewer seeds and fruits for hungry animals. Finally, pollinators, like other insects and arthropods, are themselves rich food sources for other animals. Take birds, for example. The adults of about ¼ of bird species include insects in their diet. More significantly, Dr. Doug Tallamy explains that about 96% of terrestrial bird species feed insects (and other arthropods) to their chicks. And they need a lot of them. His research shows that a single clutch of Carolina Chickadee hatchlings eat thousands of insects! In short, without insects (including pollinators), the web of life fails.
(Sources: https://xerces.org/pollinator-conservation/; “Bringing Nature Home,” http://blog.nwf.org/2015/04/chickadees-show-why-birds-need-native-trees/; https://www.audubon.org/news/why-native-plants-are-better-birds-and-people)
WHY POLLINATORS ARE IN TROUBLE
Pollinators (and insects generally) are in serious trouble. Recent studies show a disturbing and significant decline in overall insect biomass (see here and here). The reasons are varied, complex, and not yet fully understood (see here and here), but here are some of them.
- Habitat loss and fragmentation. Pollinators‒like other wildlife‒need habitat for feeding, mating, raising young, and shelter. However, as humans expand cities, collect resources, and farm, pollinators and other insects have fewer and fewer places to go. Likewise, even where small habitat areas remain, these may not be sufficiently large, or may be too fragmented and distant from each other, to meet pollinators’ needs.
(Sources: https://www.ipbes.net/article/press-release-pollinators-vital-our-food-supply-under-threat; http://greatpollinatorproject.org/conservation/major-threats-to-pollinators; “Bringing Nature Home” and http://www.bringingnaturehome.net/gardening-for-life.html)
- Habitat degradation. Human practices can also make life hard for pollinators. For example, heavy foot or vehicle traffic can compact soil until it’s unusable by ground-nesting bees. And urban areas’ ubiquitous pavement and lack of plant diversity stress pollinator and other insect populations.
(Sources: http://greatpollinatorproject.org/conservation/major-threats-to-pollinators; https://www.sciencedaily.com/releases/2017/08/170802153907.htm)
- Light pollution. Artificial lights can confound nocturnal insects in various ways, such as hindering the location of mates, leading to exhaustion or death of insects that mistake it for lunar light, exposing insects to predators, and more.
- Climate change. Scientists are discovering the adverse consequences that climate change visits upon pollinators. For example, one study has found that earlier and longer flowering seasons due to climate change are actually associated with reduced Bumble Bee numbers. And more generally, a changing climate pattern may cause a timing “mismatch” between when pollinators hatch and when the plants on which they depend bloom. A recent study in Puerto Rico’s Luquillo Rainforest documented a loss of insect mass of 30-60 times in sticky traps over a 26-year period (yes, you’re reading those numbers right), which the authors attributed primarily to climate change.
(Sources: https://news.ncsu.edu/2017/09/climates-effects-on-flowers-critical-for-bumble-bees/; https://blog.ucsusa.org/science-blogger/timing-pollinators-and-the-impact-of-climate-change; http://greatpollinatorproject.org/conservation/major-threats-to-pollinators; https://xerces.org/bumblebee-threats/; https://www.pnas.org/content/115/44/E10397)
- Herbicides and insecticides. Herbicides can reduce the number of plants available for pollinators and other insects. Using insecticides in our gardens kills not only “bad” insects, but also those beneficial insects that keep other insect populations in check. And some insecticides create special problems for bees, the most effective pollinators. For example, a recent Xerces Society report indicates that even sub-lethal doses of Neonicotinoids, a common insecticide used in both home gardens and agriculture, harm bees in various ways.
(Sources: http://www.xerces.org/wp-content/uploads/2016/10/HowNeonicsCanKillBees_XercesSociety_Nov2016.pdf; http://greatpollinatorproject.org/conservation/major-threats-to-pollinators; http://pollinator.org/learning-center/pesticides; https://www.ipbes.net/article/press-release-pollinators-vital-our-food-supply-under-threat)
- Introduction of non-native species and diseases. As we will discuss more in a later installment, insects (including pollinators) often cannot eat non-native plants because they contain chemicals that local insects did not evolve to consume. Some of these non-native plants are invasive, meaning that they can crowd out native plants, to the detriment of local insects. This happens because the animals that would normally keep these invasive plants in check don’t exist here. A prime example of this is the Chinese Tallow tree (Triadica sebifera). Likewise, non-native insects and diseases hitchhiking on imported plants can adversely affect native plants.
(Sources: “Bringing Nature Home” and http://www.bringingnaturehome.net/gardening-for-life.html; https://www.ipbes.net/article/press-release-pollinators-vital-our-food-supply-under-threat; http://greatpollinatorproject.org/conservation/major-threats-to-pollinators; http://www.tsusinvasives.org/home/database/triadica-sebifera)
HOW OUR WILDSCAPES HELP POLLINATORS
Fortunately, we can each do something to help pollinators‒right here, right now, right in our own gardens. In the words of Dr. Tallamy in “Bringing Nature Home”: “[N]ow, for the first time in its history, gardening has taken on a role that transcends the needs of the gardener. Like it or not, gardeners have become important players in the management of our nation’s wildlife. It is now within the power of individual gardeners to do something that we all dream of doing: to make a difference.”
We make that difference when we garden with plants native to our eco-region and adapt our gardening methods with wildlife in mind.
Now, let me be clear. These individual efforts are not enough by themselves: there must also be top-down change at the international, national, state, county, and municipal levels, along with our individual wildscaping, to save insects. I think of the players needed to save insects as forming a chain, and a chain doesn’t work without all of its links.
But we are one of those links‒and a critical one! That’s because, when we garden for wildlife, we can have a positive impact on the diversity of flora and fauna in our eco-system. I like to tell folks that it’s less the size of each wildscape, but more the number of people who have them that matters. The more wildscapes there are, and the closer they are one to another, the better they support pollinators. Our home wildscapes can together form the “stepping stones” that pollinators need to move around, survive, and thrive.
The realization that I could improve biodiversity simply by how I garden transformed my world view. I felt empowered knowing that I could improve something about which I’d felt helpless before. And I see clearly now that my purpose is to bring this same message of empowerment to as many people as I can.
We may not personally be able to change everything harming pollinators, but we can with certainty change their world for the better‒one garden at a time.
Stay tuned for more installments in this wildscaping series.
Postscript: I cannot highly enough recommend Dr. Doug Tallamy’s book Bringing Nature Home. I had already been wildscaping for about 3 years when I read it, and even at that point, it transformed my way of thinking! For the highlights, you may visit Dr. Tallamy’s website, or view one of his many presentations on Youtube. I tell folks that if I could recommend only one book on the “why” of wildscaping, this would be it.