Land use and pollinator dependency drives global patterns of pollen limitation in the Anthropocene

Joanne M Bennett,Laura A Burkle,Janette A Steets,Jing Xia,Jana C Vamosi,Junmin Li,James G Rodger,Tiffany M Knight,Tia-Lynn Ashman,Leandro Freitas,Allan G Ellis,Jean H Burns,Marina Wolowski,Valentin Ştefan,Martin Burd,Gerardo Arceo-Gómez,Walter Durka

doi:10.1038/s41467-020-17751-y

Abstract

Land use change, by disrupting the co-evolved interactions between plants and their pollinators, could be causing plant reproduction to be limited by pollen supply. Using a phylogenetically controlled meta-analysis on over 2200 experimental studies and more than 1200 wild plants, we ask if land use intensification is causing plant reproduction to be pollen limited at global scales. Here we report that plants reliant on pollinators in urban settings are more pollen limited than similarly pollinator-reliant plants in other landscapes. Plants functionally specialized on bee pollinators are more pollen limited in natural than managed vegetation, but the reverse is true for plants pollinated exclusively by a non-bee functional group or those pollinated by multiple functional groups. Plants ecologically specialized on a single pollinator taxon were extremely pollen limited across land use types. These results suggest that while urbanization intensifies pollen limitation, ecologically and functionally specialized plants are at risk of pollen limitation across land use categories.

Highlights

Land use change, by disrupting the co-evolved interactions between plants and their pollinators, could be causing plant reproduction to be limited by pollen supply
How plant reproduction responds to land use via any declines in pollinators has important implications for much of the world’s flora[12], yet the effects of land use changes on pollen limitation of wild plant reproduction have not been evaluated on a global scale[13]
The consequences of anthropogenic disturbances for pollen limitation of plant reproduction are likely to vary with degree of plant dependence on pollinators, as well as level of ecological or functional specialization[14], in addition to plant traits that reflect the evolutionary history of their interactions with their pollinators, such as floral symmetry[15,16]

Summary

Introduction

By disrupting the co-evolved interactions between plants and their pollinators, could be causing plant reproduction to be limited by pollen supply. The consequences of anthropogenic disturbances for pollen limitation of plant reproduction (hereafter PL) are likely to vary with degree of plant dependence on pollinators, as well as level of ecological or functional specialization[14], in addition to plant traits that reflect the evolutionary history of their interactions with their pollinators, such as floral symmetry[15,16]. The degree to which pollen receipt limits plant reproduction has been studied in thousands of independent experiments that compare fruit or seed production of flowers exposed to natural pollination with those receiving supplemental pollination. This standardized experimental approach provides important insight to assess global drivers of PL via meta-analysis while controlling for plant phylogenetic history[17,18]. Does high pollinator dependency and high ecological or functional pollinator specialization place plants at higher risk of PL, while autofertility or pollinator generalization buffer plant reproduction from PL, in the face of land use modification?

Methods

Results

Conclusion