Pollinators

Loss of remnant vegetation and landscape complexity through agricultural intensification reduces the abundance and diversity of beneficial insects such as pollinators and natural enemies of pests (predators/parasitoids). The Canterbury Plains (CP), New Zealand, is a highly intensified agricultural region that has lost almost all remnant native woody vegetation.

Understanding the key pollinators of rare plants is important for a holistic assessment of ecosystem health, as the impact on a given species can travel through the network, affecting other species. Many specialist calcicolous (limestone-specific) plants are rare. Conservation management plans have been developed to assist in the survival of these rare plant species, but these rarely include information on pollinators.

Assessments of the effects of invertebrate herbivores on high-altitude plants have seldom taken into account both mutualistic and antagonistic interactions. To evaluate the effect of herbivores (antagonists) and pollinators (mutualists) on the female reproductive success of the high-Andean perennial herb Alstroemeria umbellata, we separately and simultaneously excluded aphids (herbivores), and bees and bumblebees (pollinators) in a 2×2 factorial design. In flowers with pollinators excluded, aphids did not reduce seed set per flower (i.e., a direct effect).