Flower plants weakened by decline of pollinators

An international study of 1,174 floral species estimates that half of them are threatened by the disappearance of pollinators, suggesting significant repercussions for all biodiversity.

by Elie Herbert

From pollinating animal survival also depends on tens of thousands of flower plant species. Without these bees, butterflies, drones, birds or bats that work for the transport of pollen, indispensable to fertilization and seed formation, the reproduction of a multitude of plants becomes impossible. Yet the spread of neurotoxic pesticides and the loss of floral abundance induced by intensive monocultures decimate these animal species for several decades. According to A published study Wednesday, October 13 in the Review Science Advances , half of the planets of the planet, or nearly 175,000 plant species on 350,000, would be likely to disappear.

Although the pollination of plants is not only the fact of animals, the insects intervene exclusively in the pollination of more than eight species of in ten flower plants. To a lesser extent, vertebrates focus on 6% of vegetable pollinations. Other natural mechanisms, such as self-certification (the plant ensures its reproduction by its own pollen) or the action of the wind, allow some plants to reproduce without the intervention of pollinators. If many plant species depend on one of these factors, others are able to conjugate several.

The 21 international researchers at the origin of this study, driven by two South African and German teams, brought together three large databases compiling thousands of pollination experiments carried out on the surface of the globe. For each plant, these experiments reflect their dependence on animal pollination, measuring their ability to produce seeds and then in the absence of pollinators.

Bern fertility

In total, 614 studies have been incorporated into this “meta analysis”, whose interest is to synthesize existing data from a set of publications. The sample analyzed by scientists apprehends 143 flowering plant families for which pollination experiments could be collected.

The findings that come out of them are of concern and reflect a grain fertility. Without the action of pollinators, a third of the species of flowering plants no longer produce seed all and half of them see their reduced fertility of 80% or more – instead of 10 seeds, they generate More than 2. “To obtain this estimate, we calculated the median contribution of pollinators for the 1,174 species of our sample, explains James Rodger, researcher in the Department of Botanical and Zoology of the University of Stellenbosch in South Africa and First author of this study. This means that for half of the species, animal pollinators contribute to 80% or more of seed production. “It is this median value, extrapolate to all existing flowering plants, which leads to the final estimate of 175,000 plant species substantially weakened by the announced disappearance of pollinators.

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