AsianScientist (Oct. 17, 2018) – Scientists from Singapore and the UK have warned that the combined impact of deforestation and wildlife exploitation on bird numbers is severely underestimated and could lead to some species becoming extinct. Their findings are published in Nature Communications.
Tropical forests are the most biodiverse ecosystem globally. However, extensive loss of tropical forests, driven primarily by the expansion of agricultural land, threatens the survival of forest-dwelling species. Coupled with other anthropogenic disturbance such as logging, hunting and fires, the threat to biodiversity in these forests is amplified.
While the International Union for Conservation of Nature (IUCN) has been tracking the different forms of threats to wildlife, the assessments tend to look at each form of threat separately. Researchers led by Dr. William Symes of the National University of Singapore found that these threats are in fact interconnected, and their combined impact could be more severe than currently estimated.
The scientists focused on Sundaland, a hotspot of biodiversity in Southeast Asia spanning Borneo, Sumatra, Java and Peninsular Malaysia, where habitat loss, hunting and wildlife trade are particularly intense. Looking at 308 forest-dependent bird species, they found that that 89 percent of the species examined had experienced an average habitat loss of 16 percent due to deforestation. The researchers also estimated that wildlife exploitation had led to a 37 percent decline in mean population on average.
Among the bird species studied, the researchers also identified 77 commercially traded species that are more commonly exploited. They found that the estimated average decline for these exploited species was 15.3 percent from deforestation alone, but when combined with the effects of exploitation, the estimated average decline was drastically increased to 51.9 percent.
In addition, the assessment of the combined impact of deforestation and exploitation in the study suggested that a total of 51 species should be listed as critically endangered, endangered or vulnerable, nearly doubling the number currently listed by IUCN. The researchers caution that 50 to 90 of forest-dependent bird species in the region, such as the Ruby-throated Bulbul, the Brown-Cheeked Bulbul and the White-Crowned Hornbill will be extinct by 2100.
“Recent extinctions like the passenger pigeon and the dodo present common traits like the simultaneous combination of habitat loss and active hunting. This fatal combination of ingredients is present for dozens of unique bird species in Sundaland. At current rates, vanishing forests and enormous trapping pressures are likely to drive many of them to extinction in the near future,” said Symes.
The article can be found at: Symes et al. (2018) Combined Impacts of Deforestation and Wildlife Trade on Tropical Biodiversity Are Severely Underestimated.
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Source: National University of Singapore; Photo: Francesco Veronesi/Wikimedia Commons/CC0.
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