The Amazon basin is the largest and most species-rich tropical forest and river system in the world. It plays a vital role in global climate regulation, conservation of biodiversity, and is home to hundreds of traditional indigenous cultures. At the same time, the area is under severe pressure from threats such as deforestation, fires and climate change.
Unfortunately, the list does not end there.
"Another, more invisible and insidious threat, is the excessive harvest of animals and fish," Professor Torbjørn Haugaasen says.
Important food source
"Hunting and fishing are very important sources of protein for more than 20 million people in the region.”
The population in the Amazon has the highest per capita intake of fish protein on the planet. Haugaasen further states that this harvest in many cases is unsustainable and some animal and fish population numbers are falling rapidly.
"As of today, we do not know how hunting and fishing affect the ecosystem on a larger scale.”
Currently, there is an intense debate among scientists about whether the structures of the forest ecosystem itself are threatened by the locals’ hunting. Researchers are concerned that ‘empty forests’ possibly lose completely essential ecological functions.
"We also wonder if one of these features is carbon storage.”
The researchers' hypothesis is that larger, untouched forest areas gradually lose carbon due to excessive hunting.
“Hunting for important seed dispersers, like monkeys and fish, interferes and delays the spread and the growth of many trees and lianas.”
He explains that it is possible that the shortage of seed dispersers disturbs the entire dynamics of the forest.
"When the trees are unable to distribute their seeds, recruitment is hindered, and they are replaced by other types of wood with other characteristics.
Trees with large seeds that are dispersed by large animals that are often hunted are often hardwoods and store a lot of carbon. If these trees have no recruitment, slowly, but certainly, there will be fewer trees of hardwood. These are replaced with trees that store less carbon and this leads to a ‘carbon leakage’ as the structure of the forest changes.
"However, this hypothesis and its implications for carbon storage in tropical forests has never been investigated on a large scale.”
Food security meets natural resource management
Haugaasen’s project, "Cascading consequences of hunting and fishing for ecosystem services in Amazonian forest", has been awarded funding from the Norwegian Research Council’s MILJØFORSK-program - Environmental Research for a Green Transition.
It is a four-year project comprising eight scientific cooperative institutions.
"The project addresses some of the most critical issues at the interface between food security, biodiversity conservation, natural resource management and land-use change in Amazonia, and global climate change,” Haugaasen concludes.