Fast-growing, small-seeded trees are taking over Brazil’s forests, particularly in regions suffering from high deforestation. These fast-growing species, though capable of surviving quickly, are less dense and shorter-lived than the trees they replace. This transformation will greatly impact the forests’ ability to absorb and store carbon. It also affects wildlife dependent on large-seeded species, says a recent study.
These “winning” species—fast-growing trees with smaller seeds—are not as effective at carbon storage as the slower-growing trees they replace. The new dominant species have less dense stems and branches. This change leads to a reduction in the forest’s overall ability to absorb and retain carbon. As Brazil continues to face large-scale deforestation, this shift could accelerate climate change, weakening an important global carbon sink.
WILDLIFE AT RISK: LOSING THE BIG SEEDS
Forests with fewer large-seeded tree species also risk losing the wildlife that depends on them. Large birds, like toucans, and mammals like spider monkeys, are critical for seed dispersal. These species thrive in environments with slow-growing trees. If they decline, it could lead to a breakdown in the ecosystems that rely on their actions for regeneration, which in turn could exacerbate deforestation issues further.
RESEARCH METHODS: MAPPING THE EFFECTS OF HUMAN ACTIVITY
The study, published in Nature Ecology and Evolution, uses data from more than 1,200 tropical tree species. These data come from 270 forest plots in Brazil’s Amazon and Atlantic forests. The researchers examined forests affected by human activity, like logging, hunting, and burning. They identified the traits of “winning” and “losing” species. The findings indicate that landscapes with heavy forest cover support trees with dense wood. These trees also have large seeds. More degraded areas are dominated by fast-growing trees. These trees have smaller seeds. are impacted by deforestation.
FAST-GROWING TREES REPLACING SLOW-GROWERS
Researchers identified that in areas with significant deforestation, smaller, faster-growing species are increasingly replacing the dense, large-seeded trees. These smaller species are dispersed by smaller animals like bats and birds, which are adapted to disturbed environments. In contrast, the trees with larger seeds and dense wood are spread by larger animals. These include monkeys and toucans. These animals are slowly disappearing from these areas due to habitat loss.
THE CALL FOR URGENT CONSERVATION EFFORTS
The study calls for urgent conservation and restoration of tropical forests to prevent further degradation. Senior Investigator Professor Jos Barlow emphasizes the need to combat deforestation. He also highlights the need to address forest disturbances such as selective logging and fires. Preserving and restoring forests is crucial for maintaining the ecological balance and carbon storage capacity of these vital ecosystems.
A GLOBAL CRISIS: THE DANGERS OF HABITAT LOSS
Tropical forests are essential for biodiversity and play a significant role in regulating the global climate by absorbing greenhouse gases. Yet, over the past two decades, deforestation has wiped out millions of hectares of tropical forest annually. As a result, much of the remaining forest is now fragmented and exposed to local disturbances. The loss of biodiversity and disruption of vital ecosystem processes, such as carbon storage, is a growing concern for the global environment.
