Defaunation And Carbon Storage Affect Each Other, Says Study

Defaunation has been causing the decreasing number of large-seeded, animal-dispersed trees in the tropical forests around the globe. Yet, how the drop will impact the carbon storage remains uncertain.

Anthropocene defaunation is one of the most prevalent causes of the current biodiversity crisis on Earth. The speed at which the tropics lose the vertebrate species are one of the highest, including the bigger species being prone to population declines. These declines may have universal impact on the community and ecosystem processes due to the fact that smaller species are frequently unable to  do the ecological responsibilities of the bigger vertebrates, according to Science Mag.

The defaunation can change the composition of the community of trees through the effects on seed dispersal, causing tree recruitment to turn to smaller-seeded, animal-dispersed species. This theory is based on the evidences pointing to the tropical forests, where most of the tree species rely on vertebrate frugivores for the seed dispersal.

The reduced number of large vertebrate frugivores could lead to the decline of up to 60 percent in the growth of tree species that rely on them for the seed dispersal, along with the reduction of more than 25 percent in the normal seed sizes of the adult tree communities. With tropical forests as the representative of one of the bigger terrestrial carbon pools, performing an important responsibility in controlling the global climate, it is best to understand the importance of how the defaunation-driven reductions in large-seeded organisms could affect carbon storage in the tropical forests across the globe.

The effects of defaunation-driven shifts in the composition of tree community for carbon stocks are going to rely on how abiotically and small-seeded dispersed species differ from the large-seeded, animal-dispersed species in their likely to keep carbon. Based on some recent works from Atlantic and Amzonian forests imply that defaunation is likely to prompt aboveground carbon losses via shifts to the tree communities of less dense wood due to the small-seeded, animal-dispersed species in the Neotropical forests that are prone to have lower wood densities compared to the large-seeded species, NCBS reported.