This is my first ever post request, so let’s see if I can do it justice. Donna, over at Garden Walk, Garden Talk, has brought up the topic of ‘urban meadows’ and what they mean for pollinators and other communities of insects.
She asked me for the perspective of a biologist on whether or not urban meadows can actually be considered meadows, so for better or for worse, here is one biologist’s opinion. (She has discussed this topic eloquently and at length, so if you want a more thorough treatment of the subject, please visit her post. I won’t attempt to be as complete.)
The biological definition of a meadow is not a simple one. It is, generally, a large aggregation of herbaceous (non-woody) plants comprising many species. The “non-woody” distinction here is crucial because of succession. There is nothing in the definition of ‘meadow’ that requires it to contain nothing but native species. In fact, meadows are often extremely weedy. And, by the way, meadows often contain a lot of grass, so eliminating grass is also not a requirement of a meadow.
Succession is an oversimplification of the dynamic processes which lead to ecosystem change. All ecosystems are dynamic, full of species competing for limiting resources. The inherent variation between species, and within the heterogeneous landscape that they coexist in, leads to progressive changes in community structure over time, or succession.
The “natural progression” of ecosystems is supposedly (starting from nothing but resources) early pioneers (that colonize, grow, and reproduce quickly) to late successional species (that compete well, but colonize, grow, and reproduce slowly). In other words, a steady progression from some hypothetical “blank” landscape to a meadow comprising grasses and herbaceous things (flowering annuals and perennials, for example) to a forest.
Field and forest, forest and field
You may be wondering whether I have lost the thread of the discussion entirely when comparing urban meadows in the yards of suburbia to wild meadows and fields, but I promise that I am going somewhere with this.
My point is this: change. Wild, unmanaged ecosystems are dynamic and constantly changing. A natural meadow (and I use “natural” in the loosest sense here, given the pervasive influence of anthropogenic forces on even the wildest of meadows, the inherent presence of introduced and invasive species in any field) will change over time. There will be a constant flux of species from one year to the next, and over the course of the year, and depending on the amount of rain.
Change is beautiful
In stark contrast, someone’s garden meadow will remain static. They have in mind the individual, the plant, surrounded by bricks, lovingly tended, for years. That plant never competes for light or nutrients, never lacks for water even in the driest of summers.
“Here,” a gardener says, “Are my hydrangeas, here are my bee balms…” and so on and so forth. A garden is a work of art. In the hands of a painter like Donna, it is all detail and careful brushstrokes, colour complementarity and aesthetics.
A photograph taken by Donna at GWGT of her beautiful garden, truly a work of art!
Mother Nature is a messy gardener. She throws handfuls of seeds to the wind, crossing her fingers that some will survive. She waters them fitfully (and then too much), fertilizes them unreliably, does not account for the acidity of the soil. If Mother Nature is an artist, she is an abstract one, who covers herself in paint and rolls around on a blank canvas, nude.
“Here are some seeds, I hope some of them survive!”
There is no homogeneity, no stability in nature.
What does this mean for pollinators, or for insects in general? A few things. One is that the the heterogeneity of ecosystems, and the stochasticity inherent in environmental variables (like weather) are part of what allows for diversity. Heterogeneity contributes to the coexistence of multiple competing species. If it were not for disturbance, meadows would transform into forests, and few species (say Chestnut Oaks, Moosewood, and Black Birch) would dominate.
It is calm in the forest.
The profound and unnatural stability of gardens lends itself as well to the dominance of few insect species, those that are well-adapted to take advantage of the resources within the garden.
The implications of this are that, yes, suburban gardens provide resources for pollinators, and yes, they can contribute significantly to the populations of those pollinators which visit garden plants, but no, they cannot replace natural meadows. Thus, the diversity that we see in gardens will always be a subset of the full potential diversity of a natural area, and something will be lost.
Come and visit my garden!
Usually, it is something not well known, uncommon or rare species. You might ask, what is their value?
The answer is, we don’t know. Are you willing to find out by losing them? If not, plant urban gardens to protect those common species that we adore, and protect those natural areas for the unknown and the unknowable services they provide.
Comparing an urban meadow to a wild one is like comparing apples to oranges. Apples are so domestic. They are the reliable and sweet component of our baked goods, teas, and pies. Oranges, on the other hand, are bright, sassy, and untameable: better left raw. In my opinion, we need both to be happy.
I hope that does justice to the topic…