title: The beta-diversity of species interactions: Untangling the drivers of geographic variation in plant-pollinator diversity and function across scales.
abstract: OBJECTIVE
  Geographic patterns of biodiversity have long inspired interest in processes that shape the assembly, diversity, and dynamics of communities at different spatial scales. To study mechanisms of community assembly, ecologists often compare spatial variation in community composition (beta-diversity) across environmental and spatial gradients. These same patterns inspired evolutionary biologists to investigate how micro- and macro-evolutionary processes create gradients in biodiversity. Central to these perspectives are species interactions, which contribute to community assembly and geographic variation in evolutionary processes. However, studies of beta-diversity have predominantly focused on single trophic levels, resulting in gaps in our understanding of variation in species-interaction networks (interaction beta-diversity), especially at scales most relevant to evolutionary studies of geographic variation.
  
  
  METHODS
  We outline two challenges and their consequences in scaling-up studies of interaction beta-diversity from local to biogeographic scales using plant-pollinator interactions as a model system in ecology, evolution, and conservation.
  
  
  RESULTS
  First, we highlight how variation in regional species pools may contribute to variation in interaction beta-diversity among biogeographic regions with dissimilar evolutionary history. Second, we highlight how pollinator behavior (host-switching) links ecological networks to geographic patterns of plant-pollinator interactions and evolutionary processes. Third, we outline key unanswered questions regarding the role of geographic variation in plant-pollinator interactions for conservation and ecosystem services (pollination) in changing environments.
  
  
  CONCLUSIONS
  We conclude that the largest advances in the burgeoning field of interaction beta-diversity will come from studies that integrate frameworks in ecology, evolution, and conservation to understand the causes and consequences of interaction beta-diversity across scales.
authors.affiliation: Department of Ecology, Montana State University, Bozeman, Montana 59717 USA laura.burkle@montana.edu.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Burkle
authors.affiliation: Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130 USA.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Myers
authors.affiliation: The Wilderness Society, Bozeman, Montana 59715 USA.
authors.forename: R Travis
authors.initials: RT
authors.lastname: Belote
mesh_terms: D044822:Biodiversity; D005075:Biological Evolution; D019684:Magnoliopsida / Q000502:physiology*; D008954:Models, Biological; D054817:Pollination; D013045:Species Specificity
keywords: behavioral plasticity; biodiversity–ecosystem function; biogeographic gradient; community assembly; conservation; environmental gradient; interaction turnover; plant–pollinator network; pollination services; species pool