A seed dispersal crisis threatens European vegetation

Seed dispersal by animals (known as zoochory) is a critical ecosystem service that contributes to the regeneration, diversity and resilience of plant communities. This is especially relevant in fragmented landscapes, such as those common in Europe, where 66% of the trees and shrubs have adaptations for biotic dispersal of seeds (i.e., dispersal mediated by organisms such as birds, mammals, reptiles and ants). However, the current wave of defaunation has raised concerns over the capacity of animals to maintain an effective seed dispersal. Surprisingly, the conservation status of the seed dispersal in Europe remained unknown. We tackled this knowledge gap by reconstructing the first European-wide seed dispersal network and evaluated the conservation status of interactions between animal dispersers and plant species by assessing each interacting partner’s conservation status and population trends according to the IUCN (International Union for Conservation of Nature). To do so, we performed an extensive literature review to extract all records of seed dispersal by European animals. Our literature searches retrieved more than 50,000 publications in 26 European languages. Overall, the European (biotic) seed dispersal network included 5030 distinct interactions between 592 zoochorous plant species and 398 disperser animal species. We found that a third of the disperser species and interactions face potential extinction and that 30% of the plant species have most of their dispersers threatened or declining. Our study reveals an ongoing seed dispersal crisis in all European biomes, being particularly alarming in the Black Sea, Arctic, and Pannonian biomes. We also found large knowledge gaps in seed dispersal research in Europe, highlighted by the fact that there are no recorded dispersers for 74% of the European zoochorous plants. Moreover, the conservation status of 67% of the European plant species has not been assessed by the IUCN. The ubiquity of threatened and unevaluated interactions in Europe highlights the urgency for further scrutiny and action to conserve the seed dispersal service that underpins the resilience of European vegetation.

 

Read the full study  here:

Sara Beatriz Mendes et al., Evidence of a European seed dispersal crisis.Science386,206-211(2024).DOI:10.1126/science.ado1464

Text written by Sara Beatriz Mendes and edited by Clara Ruiz and Félix Picazo