Food vs. forests: environmental trade-offs in farming

On the prophetic side… Last week I posted on trade-offs in environmental protection. This week in Science there’s a nice article (subscription required) illustrating my point:

Farming can harm biodiversity. You have to clear away the native vegetation; chemical fertilizers, herbicides, and pesticides can pollute the environment; and irrigation affects waterways. But there’s more than one way to farm. High-intensity farming maximizes yields through high input of chemicals and minimizing areas left in native vegetation. “Wildlife-friendly” farming, in contrast, involves leaving some of the land as natural vegetation and reduced usage of chemicals. Yields are lower, but more native plants and animals can be supported. Imagine the difference between the vast croplands of the Midwest (high-intensity) and the quaint farms of New England, with hayfields, woodlots, and crops intermixed (wildlife-friendly).

The conflict then, is this: to produce a given amount of a crop, you can either do high-intensity farming on a smaller area or low-intensity farming on a larger area. High-intensity farming requires less space, but biodiversity suffers more. The authors of this week’s Science article showed how we might resolve this conflict. They used simple models to determine which farming method is best for wildlife. Surprisingly, the best solution for most species seems to be to farm intensively, leaving as much natural habitat as possible leftover.

As the human population burgeons, we’ll need to produce more and more food. I don’t think any environmentalist wants to see more industrial farming with pesticides, fertilizers, and herbicides sprayed on huge megafields, entirely lacking native vegetation. But for many animals, this may be the best possible solution because this maximizes the amount of habitat that can be left in its native state.

Right now, the areas where we are losing the most habitat, in the tropics, are also the places where “wildlife-friendly” farming is most common. To save the rainforests and other habitats in these developing regions, we may paradoxically need to encourage environmentally unfriendly, high-intensity farming. The farming technique that is most directly harmful to wildlife may, indirectly, be our best tool to save wildlife habitats.

This is just another one of the many difficult environmental trade-offs we’ll be facing in the future.