The basic reality of agricultural activity is that it reduces biological diversity, and these reductions in diversity potentially impact ecosystem services. But do some agricultural practices impact these services less than others? In a recent paper in Nature by David Crowder and colleagues, the question of how organic versus conventional farming affects predator and herbivore pathogen diversity and how this cascades to pest suppression. They show through a meta-analysis, that organic farms tend to support greater natural enemy evenness, and they hypothesize that greater evenness of enemies should better control pest populations, resulting in larger, more productive plants.

The most detailed national vegetation U.S. land-cover map to date was released today by the U.S. Geological Survey (USGS). The map, produced by the USGS Gap Analysis Program (GAP), can be viewed online and downloaded for free.

Flickr User: JRIDLEY1  See the original on Flickr »

Conservationists often place the greatest value on protecting large contiguous habitat areas. However, as two new studies (here and here) in the journal Biological Conservation show, single, isolated trees on agricultural lands can give a big boost to bird and bat species. According to the second study,

"Our results suggest that oak savanna restoration in agricultural systems does not necessarily need to be an all-or-nothing proposition. Large savanna-form oak trees scattered in agricultural fields have wildlife value, particularly for many oak-associated birds. Moreover, individual trees have a relatively small physical footprint thus allowing minimal impact on agricultural production and contributing to biological diversity at a small cost to production."