title: Landscape effects on crop pollination services: are there general patterns?
abstract: Pollination by bees and other animals increases the size, quality, or stability of harvests for 70% of leading global crops. Because native species pollinate many of these crops effectively, conserving habitats for wild pollinators within agricultural landscapes can help maintain pollination services. Using hierarchical Bayesian techniques, we synthesize the results of 23 studies - representing 16 crops on five continents - to estimate the general relationship between pollination services and distance from natural or semi-natural habitats. We find strong exponential declines in both pollinator richness and native visitation rate. Visitation rate declines more steeply, dropping to half of its maximum at 0.6 km from natural habitat, compared to 1.5 km for richness. Evidence of general decline in fruit and seed set - variables that directly affect yields - is less clear. Visitation rate drops more steeply in tropical compared with temperate regions, and slightly more steeply for social compared with solitary bees. Tropical crops pollinated primarily by social bees may therefore be most susceptible to pollination failure from habitat loss. Quantifying these general relationships can help predict consequences of land use change on pollinator communities and crop productivity, and can inform landscape conservation efforts that balance the needs of native species and people.
authors.affiliation: Conservation Science Program, WWF, Washington D.C., USA. taylor.ricketts@wwfus.org
authors.forename: Taylor H
authors.initials: TH
authors.lastname: Ricketts
authors.forename: James
authors.initials: J
authors.lastname: Regetz
authors.forename: Ingolf
authors.initials: I
authors.lastname: Steffan-Dewenter
authors.forename: Saul A
authors.initials: SA
authors.lastname: Cunningham
authors.forename: Claire
authors.initials: C
authors.lastname: Kremen
authors.forename: Anne
authors.initials: A
authors.lastname: Bogdanski
authors.forename: Barbara
authors.initials: B
authors.lastname: Gemmill-Herren
authors.forename: Sarah S
authors.initials: SS
authors.lastname: Greenleaf
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Klein
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Mayfield
authors.forename: Lora A
authors.initials: LA
authors.lastname: Morandin
authors.forename: Alfred
authors.initials: A
authors.lastname: Ochieng'
authors.forename: Simon G
authors.initials: SG
authors.lastname: Potts
authors.forename: Blande F
authors.initials: BF
authors.lastname: Viana
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D001516:Bees; D018556:Crops, Agricultural / Q000254:growth & development / Q000502:physiology*; D017753:Ecosystem; D005247:Feeding Behavior; D005638:Fruit / Q000254:growth & development; D008954:Models, Biological; D054817:Pollination / Q000502:physiology*; D012639:Seeds / Q000254:growth & development; D014329:Tropical Climate