Land sparing or sharing: Strategies for conservation of arable plant diversity

Abstract

Strategies to achieve agricultural production and biodiversity conservation fall into two categories, land-sparing or land-sharing. Plant species richness under organic arable (land sharing) versus conventional arable with land set-aside for conservation (land sparing) was evaluated on adjacent farms to compare these strategies. Sampled plant species richness was significantly higher under organic than conventional arable, as expected, but very similar to set-aside. Nevertheless, the Chao1 estimator of total plant species richness indicated that the larger area available to plants under organic arable may sustain more scarce species leading to a higher species richness. It appears that the conservation value of sparing versus sharing depends on the relative species richness of the portion of land spared (set-aside) compared to the larger area of shared land (organic), and not with the species richness on conventionally cropped land. Furthermore, in theory the land-shared use will have greater capacity to sustain populations of scarce low-density species simply due 100 % of the land area being available to these species. These are an important principals for assessing land sparing versus sharing strategies seeking to balance production and biodiversity conservation not just for arable land but all agricultural land uses.