Widespread vulnerability of flowering plant seed production to pollinator declines

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.

Understanding effects of floral products on bee parasites: Mechanisms, synergism, and ecological complexity

“…At the same time, this understanding can open new avenues for promoting pollinator health. Given mounting concerns about ongoing bee declines ( Potts et al, 2010 ; Rodger et al, 2021 ; Vanbergen and Initiative, 2013 ; Zattara and Aizen, 2021 ), and the recognition that parasites, in combination with other stressors, may be contributing to these declines ( Averill et al, 2021 ; Cameron et al, 2011 ; Goulson et al, 2015 ), there has been a recent surge in interest in the therapeutic and preventive potential of phytochemicals against bee disease. Much of this work has been motivated by an interest in controlling disease in commercial honey bee colonies, and includes many phytochemicals that are unlikely to be encountered by wild-foraging bees, at least not at the concentrations to which they are exposed in experimental studies (e.g., Boncristiani et al, 2021 ; Flesar et al, 2010 ; Maistrello et al, 2008 ).…”

Climate influence on plant–pollinator interactions in the keystone species Vaccinium myrtillus

“…reduced plant reproduction due to limited pollen availability, is widespread in natural ecosystems (e.g., Bennett et al, 2020 ; Burd, 1994 ; Knight et al, 2005 ). Accordingly, Rodger et al ( 2021 ) conclude that an absence of pollinators would strongly reduce reproduction by seed for 50% of flowering plants, and that one‐third of these species are completely dependent on pollinators for seed production. This suggests that animal‐pollinated plants are vulnerable to changes in plant–pollinator interactions.…”

Reduced visitation to buzz‐pollinated Cyanella hyacinthoides in the presence of other pollen sources in the hyperdiverse Cape Floristic Region

“…The majority of flowering plants are pollinated by animals (Ollerton et al, 2011 ; Rodger et al, 2021 ), and most animal‐pollinated species offer resources such as pollen, nectar, oils, and scents as rewards to attract floral visitors. The degree to which these resources are accessible to floral visitors varies between plant species, and the accessibility of resources is often modulated through morphological restrictions, such as nectar tubes or keel flowers (Córdoba & Cocucci, 2011 ; Santamaría & Rodríguez‐Gironés, 2015 ).…”