Does Scale Matter?
Puddock Hill Journal #33: You don’t need a big plot of land to help revive nature.
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‘Tis giving time…
About a month ago, a friend and frequent reader of this newsletter told me she found my reports on Puddock Hill “intimidating” because she has far less land than we do (she lives in a suburban subdivision) and employs a normal weekly gardening service.
I thought of this conversation while reading a new paper in the journal Agriculture, Ecosystems & Environment entitled “A little does a lot: Can small-scale planting for pollinators make a difference?”
Spoiler alert: yes, it can.
The authors of the paper reviewed data from existing studies and conducted their own research in an effort to determine the scale required to benefit pollinator conservation. They concluded that “Pollinator conservation interventions increased species richness and abundance in almost all of the studies examined, with the greatest increases in pollinator ecological metrics seen from hedgerows covering 40 m² and herbaceous interventions at 500 m².”
Let’s break this down a bit. Forty square meters is a tiny fraction of an acre—only about one percent, in fact. Five hundred square meters is only twelve percent of an acre. In other words, devoting small spaces in suburban and even urban gardens to pollinator promotion has been proved to impact both the numbers of pollinators present in an area and species variety. Modest efforts at aiding bees work!
What kind of interventions exactly? The paper homes in on three types of landscape, all of which are easily accessible to the casual gardener on a budget:
Herbaceous plantings. Think native perennials in a border or foundation planting.
Hedgerows. But only when kept messy.
Lawns. Depending upon when you mow.
Herbaceous plantings, especially of native species, seem like the most obvious choice and indeed have the most impact. “The meta-analysis of ‘small intervention’ types suggested herbaceous interventions were the most successful intervention type, in terms of pollinator diversity increases per unit area.”
For those following the No Mow May movement (which I wrote a bit about here), the proper timing of lawn cutting may also be familiar. The idea behind No Mow May is to let clover and other small flowers bloom in the lawn during a period of time when other sources of pollen are not yet available to bees, especially around thoroughly cultivated gardens.
The paper confirms the wisdom of this approach, noting that
The results of the meta-analysis also suggested that alterations to the mowing regime were able to produce relatively large increases in pollinator abundance per unit area for small plot sizes. Changes to more pollinator-friendly mowing regimes include timing mowing after flowers had finished blooming; reducing mowing frequency, reducing the cut height or leaving some strips uncut. This suggests that changes to mowing can limit the disruption caused to pollinators from the loss of floral resources and can even improve habitat heterogeneity resulting in increases in pollinator population sizes.
In sum, the writers advise that we begin mowing later in spring, mow less frequently, mow higher, and avoid mowing at all where practical.
With regard to hedgerows, the advice becomes a bit more complicated, because planting, say, a privacy hedge of privet and keeping it beautifully clipped does little to no good for pollinators. For one thing, privet is non-native and indeed invasive in parts of North America, but the main thing is managing your hedges in a way that provides services to the bees and other pollinators rather than trying to impress your neighbors with the precision of your clipper work.
The authors of the paper describe the benefits of hedgerows as providing “a 3-dimensional network of twigs and branches that can be ideal nesting habitat for insect pollinators, including some solitary bee species, as well as flowering hedges offering a food source for pollinators.”
But the hedgerows they have in mind are messier things than the hedges we often see. Pollinator-supporting hedgerows must include shrubs allowed to grow tall, left unclipped (or at least clipped rarely and after flowering), and maintained in more natural form than that which we generally find in the urban and close-in suburban environment. The authors caution that “Wildlife-friendly hedgerows require very specific management, [therefore] adopting these practices and disseminating knowledge of them has thus far limited their potential as nature-based solutions for pollinator conservation.”
A major drag on effectively helping pollinators, in other words, has come from lack of education on the subject among the gardening public. But a further limitation, noted elsewhere in the paper, is “a widespread cultural aversion to ‘messy’ spaces.”
I discussed in another newsletter that backyard stewardship rests, in some part, on redefining our conception of natural beauty, and it’s important to acknowledge that urban and suburban gardeners who want to help nature might be challenging the more conventional aesthetic sensibilities of their neighbors. But this only reinforces another point I’ve made in the past: Backyard stewardship is a group effort.
In fact, one of the more interesting points the paper makes is that small-scale attempts to support pollinators, when executed by multiple gardeners located not too far apart, are more effective than the same practices applied on a small scale on larger plots such as farms. One can easily imagine, for example, that small plots of wildflowers on a vast farm might be farther apart than two comparable plots on either side of a densely packed neighborhood. As a consequence, “The results of this study primarily demonstrated that small interventions have demonstrable benefits to pollinator diversity on these community gardens, but only when those gardens/farms are smaller than 50,000 m².”
Fifty thousand square meters is about twelve acres, and at Puddock Hill we have sixteen. So, all things being equal, if I put a small plot of herbaceous natives in one corner of our property and a properly managed hedgerow on the other—and that’s all I do for pollinators—I will likely have less impact than urban or suburban gardeners in proximity to one another creating small refuges for pollinators in their yards.
This is a healthy reminder that larger landowners need to distribute our pollinator efforts well across the whole property, not group them in an isolated spot. But it also validates the fact that the principles of backyard stewardship benefit nature when applied even at small scale—so long as we’re not acting alone.
Either do it yourself or discuss improved stewardship practices with your landscape maintenance service, but do it. Anyone with a patch of sod can make a difference.
Anemone seed heads beckon the wind in the raised bed garden:
Our new kestrel house hangs from the trunk of a black walnut tree by the barn on a blustery fall day:
