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Birds that disperse more types of seeds have better evolutionary chances

Publicado em 11 agosto 2021

More than 70% of the plant species that produce flowers depend on birds to disperse their seeds. Birds feed on fruits from a wide range of different plants, and the interactions between birds and plants make up a tangle of complex webs.

Astudy carried out at the Institute of Biosciences of the University of São Paulo (IB-USP) in Brazil shows that the evolutionary stability of each species of bird depends on the position it occupies in these networks, increasing with the number and centrality of its interactions with potential associated plant species and the number of network connections it maintains.

The study was funded by the São Paulo Research Foundation - FAPESP and is published in the journal  Science  .

"Bird species that occupy more central positions in a network, that have more connections, tend to be more stable in macroevolutionary terms," ​​Gustavo Burin, first author of the article, told Agência FAPESP.

According to Burin, establishing this correlation between species interactions and their evolutionary dynamics was a great challenge because it required an analysis of two processes, seed dispersal and evolution, that occur on completely different time scales. Seed dispersal takes place annually, while evolution takes place over millions of years.

"We worked on this for four years, integrating data on 468 species of birds belonging to 29 seed dispersal networks," he said. “We show that the more links a bird species establishes with plant species, the greater its evolutionary possibilities.

“More precisely, the greater the evolutionary stability of a bird species, the more possibilities we have to observe its relative importance in a seed dispersal network, measured by the number and pattern of interactions established by the bird species.

"Species that occupy central positions in a network have two important traits: either they live longer or they belong to groups that accumulate many species in a relatively short time, so that if one species disappears it is replaced by many similar ones."

Among the   native birds of Brazil, examples of long-lived species include the rufous-bellied thrush (Turdus rufiventris) and the Sayaca tanager (Thraupis sayaca).

“Here we emphasize the importance of interaction with plants for the evolutionary success of bird species, but the converse may also be true in the sense that plants that may depend on more species of birds to disperse their seeds are more likely to spread and survive. . When there is a dispersed vertebrate, the seeds can be transported tens of miles from the plant, "said Burin.

This mechanism is more intense and effective in hot and humid regions less subject to seasonal variations. It is no coincidence that the main animal and plant biodiversity hotspots in the world are located in the Amazon region of Colombia and Southeast Asia.

The study combined ecological data, mathematical and computational modeling, and analytical tools derived from complex network analysis. The other co-authors are Paulo Guimarães Jr. and Tiago Quental.

More information: Gustavo Burin et al, Macroevolutionary stability predicts interaction patterns of species in seed dispersal networks, Science (2021). 

Citation: Birds that disperse more types of seed have better evolutionary chances (2021, August 11) retrieved 12 August 2021 from https://phys.org/news/2021-08-birds-disperse-seed-evolutionary-chances.html