The utility of fundamental ecological research of plant-pollinator interactions as the basis for landscape management practices

Pollination is a key component of biodiversity which is directly responsible for the maintenance of ecosystem function. We are subject to an ongoing global pollination crisis, and following the "International Pollinators Initiative" (São Paulo declaration on pollinators, December 1999), experts point to a lack of baseline ecological data for plant-pollinator interactions on which to develop integrated landscape management strategies. The current pollination crisis demonstrates the crucial link between the maintenance of 'healthy' natural ecosystems and the needs of sustainable agriculture. We present here the interim findings of a long-term study of the biotic and abiotic factors that determine the diversity of pollinators in a dynamic Mediterranean landscape, considered to be one of the global hotspots for entomophily and bee diversity. Our model system comprises a mosaic of regenerating post-fire habitats encompassing a wide variety of disturbance. Employing a space-for-time substitution (chronosequence) approach allows the assessment of the combined impacts of fire, habitat loss, fragmentation, grazing and introduction of exotic pollinators upon native pollinators. Habitat characteristics determining bee diversity and abundance include: floral diversity and abundance, quality and quantity of energy available (nectar and pollen), and availability of nesting substrates and nest building materials. To quantify the overall pollination effectiveness of these communities, the delivery of conspecific pollen to receptive stigmas and seed and fruit production are being measured on several core flowering plant species and investigated at the community, guild and individual species levels so that key components can be identified. By simultaneously assessing the fundamental determinants of pollinator diversity and effectiveness, and relating these directly to various disturbance regimes, we can construct a comprehensive model. Our study demonstrates the type of integrated approach required to provide the essential ecological data necessary to produce such models, upon which landscape management practices rely. Pollinator management needs to be addressed at the ecosystem-level to conserve and restore natural and seminatural habitats and optimise pollinator services in agricultural systems.