Critical animal-plant species interactions being lost

Uploaded 05/27/2022

Critical animal-plant species interactions being lost through defaunation puts many plants in danger of extinction

Critical animal-plant species interactions being lost

Critical animal-plant species interactions being lost through defaunation puts many plants in danger of extinction. Frugivores are animals that eat and get nutrients from fruit and benefit the fruit-producing plant by dispersing its seed. It is calculated that approximately half of plant species depend on this fundamental mutualistic relationship.

Many plants rely on frugivores to disperse their seeds to shift their range to more optimal ecological conditions. But seed dispersing of wild plants has been greatly disrupted by defaunation, habitat fragmentation and invasive species, greatly limiting the chances of a plant species to migrate.

The combination of a rapidly changing environment through climate change and human disruptions puts in danger many plants species. Species that need to shift their range may not have their mutualistic bird and mammals frugivore partners to facilitate this shift.

In this great paper the authors developed predictive models for seed dispersal interactions involving mammals and birds to estimate seed dispersal distance and the impact of gut passage on germination.

They tested the model for future novel community scenarios by using interactions involving introduced species as a proxy for interactions in future novel communities.

Seed dispersal and defaunation

Furthermore, the authors investigated how alterations of mammal and bird species composition has affected seed dispersal function globally by focusing on long-distance dispersal because of its key role in population expansion, gene flow, and recovery from landscape disturbance.

Finally, the authors addressed the negative interaction between defaunation and climate change by estimating how altered bird and mammal assemblages influence the capacity of plants to track local climate change through seed dispersal.

The authors estimated that already existing mammal and bird defaunation has already reduced the capacity of plants to track climate change by 60% globally. The future loss of vulnerable and endangered species from their current ranges would result in a further reduction of 15% globally.

Human caused quick climate change together with defaunation of birds and mammals reduces the ability of plants to shift their ranges. Habitat fragmentation and other land-use changes by human amplify the constraints on plant range shifts.

This issue should urgently be addressed to mitigate the loss of wild plant species by measures such as promoting connectivity between habitats and reintroducing large bodied animals that are long distance dispersers.

Species Interactions