title: Pollination decays in biodiversity hotspots.
abstract: As pollinators decline globally, competition for their services is expected to intensify, and this antagonism may be most severe where the number of plant species is the greatest. Using meta-analysis and comparative phylogenetic analysis, we provide a global-scale test of whether reproduction becomes more limited by pollen receipt (pollen limitation) as the number of coexisting plant species increases. As predicted, we find a significant positive relationship between pollen limitation and species richness. In addition, this pattern is particularly strong for species that are obligately outcrossing and for trees relative to herbs or shrubs. We suggest that plants occurring in species-rich communities may be more prone to pollen limitation because of interspecific competition for pollinators. As a consequence, plants in biodiversity hotspots may have a higher risk of extinction and/or experience increased selection pressure to specialize on certain pollinators or diversify into different phenological niches. The combination of higher pollen limitation and habitat destruction represents a dual risk to tropical plant species that has not been previously identified.
authors.affiliation: Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4. jvamosi@ucalgary.ca
authors.forename: Jana C
authors.initials: JC
authors.lastname: Vamosi
authors.forename: Tiffany M
authors.initials: TM
authors.lastname: Knight
authors.forename: Janette A
authors.initials: JA
authors.lastname: Steets
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Mazer
authors.forename: Martin
authors.initials: M
authors.lastname: Burd
authors.forename: Tia-Lynn
authors.initials: TL
authors.lastname: Ashman
mesh_terms: D044822:Biodiversity; D003247:Conservation of Natural Resources; D017753:Ecosystem; D004777:Environment; D035264:Flowers; D005843:Geography; D015201:Meta-Analysis as Topic; D008954:Models, Biological; D008962:Models, Theoretical; D010802:Phylogeny; D018521:Plant Physiological Phenomena; D010944:Plants; D011058:Pollen / Q000502:physiology*; D012984:Software; D013045:Species Specificity; D014197:Trees