Legal and illegal logging increased more than 600 percent in Ghana during a 15-year period. Credit: Nicole Arcilla
Posted: 08 Sep 2015 11:11 AM PDT
The devastating impact has been revealed of illegal logging on bird communities in the understory layer of Ghana’s Upper Guinea rain forests, one of the world’s 25 “biodiversity hotspots” where the most biologically rich ecosystems are most threatened…. Researchers found that the level of legal and illegal logging increased more than 600 percent between 1995 and 2010 — six times greater than the maximum sustainable rate. They also discovered that the abundance of forest understory bird species declined more than 50 percent during the same period. Species richness, or the number of different understory bird species represented, also showed declining trends. The bird communities showed no evidence of post-logging recovery. “The numbers don’t lie and they don’t have a political agenda. These numbers are shocking,” said lead author Nicole Arcilla, PhD, postdoctoral research associate in the Biodiversity, Earth & Environmental Sciences (BEES) Department in Drexel’s College of Arts and Sciences. “Our most disturbing finding was that more than half of all understory birds had vanished in only 15 years. If things continue as they are, in a few decades, these incredibly beautiful forests and their unique wildlife will be largely depleted, which would be a huge loss to Ghana, Africa and the world.”… The researchers sampled bird communities in logged and unlogged forests in Ghana from 2008-2010, and compared their data with findings from fieldwork in the same study area in Ghana from 1993-1995, when illegal logging was not as prevalent. The evidence revealed severe declines in Ghana’s Upper Guinea forest understory bird communities during the 15-year period between the two datasets. Abundance declines appear to be pervasive across the understory bird community and to be driving declines in species richness over time. Species such as the yellow-whiskered greenbul declined by 73 percent, and the icterine greenbul declined by 90 percent.
Results further indicate that Ghana’s forestry management system has seriously deteriorated due to widespread increases in logging intensity coupled with extensive illegal logging, which has decreased or eliminated post-logging forest recovery. The absence of many conservation priority species from 2008 to 2010 field data suggests continuing population declines and increasing rarity of species at risk of extinction…. “Illegal logging is having serious impacts — not just on the forests themselves — but on the animals,” said Arcilla. “It’s reasonable to assume that if the birds are being this powerfully impacted, it’s impacting other groups, such as mammals, reptiles, amphibians and arthropods. Birds — like the ‘canary in a coal mine’ — are a great indicator of what’s happening to other animals, and eventually, what will happen to us.”
The situation, though dire, is not hopeless, according to the researchers. “There is enormous potential for regenerating logged forests for bird conservation,” the report states. For this conservation potential to be realized, according to the researchers, urgent measures must be taken to protect these surviving forest fragments and prevent further forest bird declines. Such actions would ideally include increasing forest ranger patrols, increasing forest law enforcement and increasing implementation of measures to prevent illegal logging, such as making roadblocks in logging roads following legal logging operations to prevent incursion by illegal logging operations. “Solutions are complex and socially complicated, but the problem is solvable if there is motivation and interest,” said Arcilla…..
Nicola Arcilla, Lars H. Holbech, Sean O’Donnell. Severe declines of understory birds follow illegal logging in Upper Guinea forests of Ghana, West Africa. Biological Conservation, 2015; 188: 41 DOI: 10.1016/j.biocon.2015.02.010