The plant-pollinator landscape

Abstract

Pollinators feed on patchily distributed plants, forcing them to decide when to move between patches and when to switch plant species. The "plant-pollinator landscape' is shaped by an interacting set of plant and pollinator attributes: flowering phenology sets the distance that pollinators need to travel between patches of a given species to obtain sufficient food, while the pollinators' search capacities and dietary specificity determines the likelihood that they can and will make that journey. These sets of traits do not vary independently, allowing us to identify several characteristic landscapes and the types of organisms that occupy them. This chapter describes five such landscapes, attempting in each case to determine whether phenological variation within plant species helps to explain the ability of pollinators to persist. The first two landscapes are occupied by highly specialized pollinators and (respectively) synchronously flowering and asynchronously flowering plants. Intraspecific phenological variation is likely to have critical consequences for pollinator persistence in these two landscapes. The third and fourth landscapes are occupied by relatively generalized pollinators and (respectively) synchronously flowering and asynchronously flowering plants. The former is probably the most common landscape, encompassing most temperate plant-pollinator interactions. Pollinators in these landscapes are less likely to be strongly influenced by phenological variation in any one of their resource plants, due to their ability to switch foods easily while remaining local. The fifth landscape is occupied by generalist pollinators that may migrate. Little is known about resource use of individual migrants, but it is possible that at least some of them rely on geographical gradients in flowering time of certain preferred species. -from Author