Widespread vulnerability of flowering plant seed production to pollinator declines.

James G Rodger ,Laura A Burkle ,Joanne M Bennett ,Cang Hui ,Martin Burd ,Mialy Harindra Razanajatovo ,Janette A Steets ,Mark Van Kleunen ,Tiffany M Knight ,Walter Durka ,Leandro Freitas ,Gerardo Arceo‐Gómez ,Xia Ji ,Jana C Vamosi ,Tia Lynn Ashman ,Anton Pauw ,Jean H Burns ,Marina Wolowski ,Junmin Li ,Jurene E Kemp ,Allan G Ellis

doi:10.1126/sciadv.abd3524

Abstract

Despite evidence of pollinator declines from many regions across the globe, the threat this poses to plant populations is not clear because plants can often produce seeds without animal pollinators. Here, we quantify pollinator contribution to seed production by comparing fertility in the presence versus the absence of pollinators for a global dataset of 1174 plant species. We estimate that, without pollinators, a third of flowering plant species would produce no seeds and half would suffer an 80% or more reduction in fertility. Pollinator contribution to plant reproduction is higher in plants with tree growth form, multiple reproductive episodes, more specialized pollination systems, and tropical distributions, making these groups especially vulnerable to reduced service from pollinators. These results suggest that, without mitigating efforts, pollinator declines have the potential to reduce reproduction for most plant species, increasing the risk of population declines.

Highlights

Most of the world’s approximately 350,000 flowering plant species engage in mutualistic relationships with animal pollinators to reproduce [1]
Pollinators make at least some contribution to seed production in 79% of species (PC > 0) and no contribution in 21% of species (PC = 0) either because they are wind-pollinated (12% of species) [1] or because pollination experiments indicate that their seed production is currently not affected by pollinators (9% of species; Fig. 1)
We estimate that pollinators contribute to seed production in 79% of flowering plant species, including about half of species that rely on pollinators for most or all (80 to 100%) of their seed production (Fig. 1)

Summary

Introduction

Most of the world’s approximately 350,000 flowering plant species engage in mutualistic relationships with animal pollinators to reproduce [1]. Declines in the abundance and diversity of pollinators have been reported from multiple continents [2,3,4,5,6,7,8], consistent with declines in wild animals overall [9, 10]. If these trends are representative, plant reproduction could be reduced by pollinator declines globally. S1) estimates PC by comparing seed or fruit production when pollinators are experimentally excluded (fexc) with that in naturally pollinated control flowers (fnat) as PC = (fnat – fexc)/fnat [15]. The importance of all animal pollinators (i.e., including insects) across flowering plants remains unknown

Methods

Results

Conclusion