Wild Side: Farms as habitat

The same principles of ecology that apply in wilderness areas apply equally well to farms.


In addition to pecking out Wild Side columns for the MV Times, my working life includes roles with BiodiversityWorks and the Betsy and Jesse Fink Family Foundation. Both entities share my interest in sustainability and conservation of biodiversity. So it’s not too surprising that I’ve been thinking a lot lately about how food production (I mean, for food humans) intersects with ecological health.

A farm, after all, is nothing more than specialized habitat. Depending on the nature of the operation, the focus may be on optimizing conditions for livestock, for row crops, or for grains. But the same principles of ecology that apply in wilderness areas apply equally well to farms. Populations, whether crop plants or wildflowers, reflect the balance of recruitment and mortality; every species has certain ecological requirements that must be met if that species is to flourish. A good farmer is a good ecologist.

And like any other habitat, a farm interacts with the different habitats that surround it. Plants and animals readily move onto a farm from outside, or from the farm to the neighboring environments. There’s no such thing as a totally enclosed ecosystem, unless you want to consider the entire planet Earth as an example.

More so than most habitats, farms are characterized by deliberately intensified biology. Huge amounts of biomass are produced in the course of a year; vast quantities of chemicals, everything from nutrients to minerals to carbon dioxide and water, move from the environment into living tissues and then back out again. Wildlife of all kinds notices this tempest of productivity. Crops or cover crops, when in bloom, pull in bees, wasps, flies, and pollinators of all sorts to exploit pollen and nectar. In return, these insects ensure productivity by pollinating fruits and vegetables.

Even the waste or surplus productivity of a farm is useful for wildlife. There is nothing, for example, that a migrating sparrow likes better than a spent tomato field, lightly frosted, full of seeds, rotting fruit, and late-season insects. Sure, sparrows migrated successfully before there were farms, and they can still do so. But the numbers of sparrows (and, for that matter, late warbler migrants like palm and yellow-rumped warblers) I’ve run into in late autumn farm fields convinces me that the birds themselves have identified this resource as an especially attractive one.

Pastures support nesting killdeer and savannah sparrows; in winter, farmland is favored by birds such as snow buntings, pipits, and horned larks in the winter, while in the warmer months, insectivorous birds of all kinds converge on farms to feed on the wealth of invertebrates.

To be sure, there are limits to the ecological merits of farms. You won’t, in general, find wildlife with very specific habitat requirements or ecological associations; farmland is the province of generalist species, plants and animals adapted to a wide range of conditions and the use of a variety of resources. If a bee species has evolved to nectar primarily on, say, blueberries, you’re unlikely to find that bee on a farm unless blueberry figures among the crops being raised. (For some insects, though, such as squash bees, farms are the preferred habitat.)

And there are negative impacts to consider. Farms occupy acreage that was once natural habitat, and they are generally dominated by non-native species — not just the crops themselves but agricultural weeds that came to North America as uninvited guests along with more desirable Old World crop species. Weed populations on farms represent source populations that can spread to surrounding areas. Moreover, anything a farmer does to boost crop production or limit pests can spill over into the surroundings; depending on the nature of a farming operation, pesticide drift, nutrient runoff, or the flow of bacterial pathogens into nearby water can be major threats to the regional ecology.

Modern methods of food production have focused, rather scarily, on increasing the scale and simplifying the ecology of farms. The goal of “Roundup-ready” crop varieties is, quite explicitly, a vast tract on which nothing other than the crop species can survive. The farm is still an ecological system; it’s just a depauperate, a really boring one that offers nothing to the surrounding landscape. I’m happy to see, in places like Martha’s Vineyard, a countermovement gaining strength. Small-scale farmers here and elsewhere are embracing the ecological relationships that a farm can be part of, rather than fighting against them.

Organic farming, regenerative agriculture, and restorative farming are three interrelated, somewhat slippery terms that describe this holistic notion of food production. Farmers can consciously mitigate or simply avoid potentially harmful practices. They can learn to rely on services, such as pollination and pest control, provided by naturally occurring bees and predators. They can build up the soil rather than depleting it and then relying on fertilizers. They can even take measures aimed purely at promoting biodiversity, secure in the notion that a healthy, resilient ecosystem is a rising tide that lifts all boats.

Farms will never be the whole solution to declining biodiversity. But they don’t have to be part of the problem.