A new study published in the journal Science has revealed that human activities and deforestation have caused a staggering 80% of tropical forests to become fragmented in the past two decades. Globally, between 51% and 67% of all forests have also been fragmented, a change that is severely impacting biodiversity and ecological integrity.
Primary Drivers of Forest Fragmentation
The researchers identified the primary causes of fragmentation, noting that most are temporary activities rather than permanent land conversions. Globally, the leading drivers are:
• Shifting agriculture Responsible for 37% of increased fragmentation.
• Forestry Accounted for 34%.
• Wildfires and commodity-driven deforestation Each contributed 14%.
The study found significant regional differences in these drivers. In the tropics, fragmentation is overwhelmingly driven by shifting agriculture (61%), while temperate forests are primarily affected by forestry (81%). In boreal regions, wildfires and forestry are the main contributors.
Threats to Biodiversity and Protected Areas
Forest fragmentation negatively impacts biodiversity through several mechanisms:
• Microclimate changes Forests become warmer and drier, harming species.
• Loss of core habitat Species that rely on large, intact habitats are threatened as forest patches shrink and become isolated.
• Disrupted connectivity movement of wildlife is restricted, leading to long-term population declines.
The study also assessed the effectiveness of protected areas. In the tropics, strictly protected areas showed 82% less fragmentation compared to non-protected areas, demonstrating their critical role. In contrast, non-tropical protected areas showed slightly higher fragmentation, with a notable increase in forestry activity.
The authors emphasized that since most fragmentation is driven by temporary activities like agriculture and forestry, there is a significant opportunity for restoration. The findings underscore the urgent need for a more comprehensive approach to conservation to achieve global biodiversity goals.