Without Birds, Lizards, and Other Vertebrate Pollinators, Plant Reproduction Could Decline by Two-Thirds

Bees tend to get the most attention as pollinators critical to the survival of plant species. But lizards, mice, bats, and other vertebrates also act as important pollinators. A new study finds that fruit and seed production drops an average 63 percent when vertebrates, but not insects, are kept away from plants.

The research, published in the journal Frontiers in Ecology and the Environment, looked at 126 animal-exclusion experiments on plants that rely on vertebrates and insects for pollination. The starkest example was among bat-pollinated plants, of which there are about 528 species worldwide. When bats were kept away, the fruit production of these plants dropped by an average 83 percent, the study found. Loss of vertebrate pollination in the tropics caused a 71 decline in fruit or seed production.

Birds are the largest contingent of vertebrate pollinators, with more than 920 species known to pollinate plants across the globe. The study found that when birds are excluded from plants, fruit or seed production declines 46 percent. But the research, led by scientists at the University of Southampton in the UK, also looked at the importance of non-flying mammals as pollinators, including ruffed lemurs, mice, possums, squirrels, and lizards.

The scientists say the study’s findings could help focus conservation efforts. “Both mammal and bird pollinators are becoming increasingly threatened with extinction over time, with an average of 2.5 species per year having moved one Red List category towards extinction in recent decades,” lead author Fabrizia Ratto, a postgraduate researcher at the University of Southampton, said in a statement. “With such a large potential impact of vertebrate pollinator loss, there is a clear need for prompt, effective conservation action for threatened flower-visiting vertebrate species.”

Source: Yale Environment 360, April 6, 2018

Fabrizia Ratto, Benno I Simmons, Rebecca Spake, Veronica Zamora-Gutierrez, Michael A MacDonald, Jennifer C Merriman, Constance J Tremlett, Guy M Poppy, Kelvin S-H Peh, and Lynn V Dicks. Global importance of vertebrate pollinators for plant reproductive success: a meta- analysis.
Front Ecol Environ 2018; 16(2): 82–90, doi: 10.1002/fee.1763