Data from: Experimental evidence that the effectiveness of conservation biological control depends on landscape complexity

1. The expansion of intensive agricultural practices is a major threat to
biodiversity and to the delivery of ecosystem services on which humans
depend. Local-scale conservation management strategies, such as
agri-environment schemes to preserve biodiversity, have been widely
adopted to reduce the negative impacts of agricultural intensification.
However, it is likely that the effectiveness of these local-scale
management actions depend on the structure and composition of the
surrounding landscape. 2. We experimentally tested the utility of floral
resource strips to improve local-scale biological control of crop pests,
when placed within a gradient of moderately simple through to highly
complex landscapes. 3. We found that experimental provision of floral
resources enhanced parasitism rates of two globally important crop pests
in moderately simple landscapes but not in highly complex ones, and this
translated into reduced pest abundances and increased crop yield. 4.
Synthesis and applications. Our results lend experimental support for the
‘intermediate landscape complexity hypothesis’, which predicts that local
conservation management will be most effective in moderately simple
agricultural landscapes, and less effective in either very simple
landscapes where there is no capacity for response, or in highly complex
landscapes where response potential is already saturated. This knowledge
will allow more targeted and cost-effective implementation of conservation
biological control programs based on an improved understanding of
landscape-dependent processes, which will reduce the negative impacts of
agricultural intensification.