Surface-active arthropods in organic vineyards, integrated vineyards and natural habitat in the Cape Floristic Region

The Cape Floristic Region (CFR), South Africa, is a biodiversity hotspot challenged by intensive wine production. Innovative approaches are being explored to optimize wine production without compromising biodiversity. As organic farming enhances biodiversity conservation in many other regions, the aim here was to assess the potential of organic vineyard management for conserving CFR soil surface arthropod diversity. Pitfall traps were used to sample arthropods in three study areas, each of which included an organic vineyard, an integrated vineyard and a natural vegetation reference habitat. Overall arthropod morphospecies richness was highest in natural sites, followed by organic vineyards and then integrated vineyards. The same trend was seen for predators, saprophages and phytophages. The ability of organic vineyards to sustain more morphospecies than integrated vineyards were partially due to higher non-crop vegetation complexity and less intense management in the organic vineyards. Arthropod assemblages were similar in organic and integrated vineyards, while both land-uses differed greatly from natural sites. Variation among natural vegetation assemblages in different study areas was also much greater than among assemblages of cultivated sites. Organic vineyard management has the potential to make an important contribution to arthropod conservation in the CFR at the field scale. However, at the landscape scale, natural habitat supports a much wider variety of morphospecies, and the preservation of natural fragments in the vineyard landscape may be the most effective measure to increase biodiversity in the winelands.