- Researchers found understory bird abundance fell by more than half in just 15 years while illegal and legal logging increased by 600 percent.
- Logging can destroy habitat while opening up what remains to poaching and other human activities.
- The study recommends that Ghana increase measures to protect its forests from illegal logging, including more forest rangers, law enforcement, and adding road blocks to logging roads.
Thousands of studies have measured the impact of logging on tropical biodiversity, but few have looked at illegal logging. This, despite the fact that illegal logging represents anywhere from 50 to 90 percent of total timber harvesting in tropical countries, according to the United Nations Environment Program. But new research in Ghana’s highly-biodiverse Upper Guinean rainforests has found that a combination of illegal and legal logging has taken a tremendous toll on birds. The researchers, headed by Nicole Arcilla, a postdoctorate researcher with Drexel’s College of Arts and Sciences, found understory bird abundance fell by more than half in just 15 years.
“The numbers don’t lie and they don’t have a political agenda. These numbers are shocking,” said Arcilla, whose paper was published in Biological Conservation.
Understory birds are species that live primarily between the canopy and the forest floor, largely feeding on insects. The team collected data on these birds from 2008 to 2010 in forest heavily impacted by illegal logging, comparing them to previous data collected from 1993 to 1995.
They found that during the fifteen-year gap, logging – both legal and illegal – increased by 600 percent, decimating the understory birds.
“Whereas analysis based on data collected in 1993–1995 estimated a partial post-logging recovery of the understory bird community at that time, data from 2008–2010 showed no indication of post-logging recovery, likely due to ongoing illegal logging following intensive legal logging operations,” reads the paper.
Illegal logging can be much more devastating than legal logging largely because it is wholly unregulated, unmanaged, and unmonitored. Illegal loggers have no limits on the number of trees, the species, or the size that they cut.
“The prescribed policies for logging, which were working, are not being followed,” Arcilla told Audubon. “And so the logging is totally unsustainable. It more resembles deforestation than logging.”
Arcilla told Mongabay that there were two sources of illegal logging: companies and rogue loggers.
“About one third of illegal timber is taken by logging companies themselves by harvesting more trees than legally allowed, and/or from areas that are supposed to be legally protected, and/or after legal permits have expired,” she explained. “The other two thirds of illegal timber are taken by illegal chainsaw operators who often operate at night in any forest to which they can gain road access, and may be armed and dangerous.”
The rampant run on forests has taken its toll. From 2001 through 2014, Ghana lost more than half a million hectares of forest – an area larger than Rhode Island – according to Global Forest Watch. This represents nearly 9 percent of the country’s total forest. In all, 92 percent of Ghana’s forests are managed as logging concessions.
“Industrial logging involves opening roads into forests that then provide ongoing access to illegal logging, farming, poaching, and permanent settlement,” said Arcilla, who noted that these concessions have few if any guards and roads are left open between logging cycles, making illegal entry easy.
It’s not surprising then that more than half of the country’s greenhouse gas emissions are linked to land use change, such as deforestation.
The view is even gloomier when looking at Ghana’s Upper Guinean rainforests. According to the paper, only 20 percent of these forests remain. Indeed, Arcilla described the region she worked in as “the Wild West.” It’s believed that 80 percent of timber in Ghana is harvested illegally. Despite this, the impact of illegal logging on biodiversity often goes unstudied.
“No one has looked at this issue in the past, to my knowledge, because illegal logging is an underworld issue, so it’s not on the books and is harder to quantify,” Arcilla noted. “But it’s so prevalent that if we don’t look at it, these forests will be destroyed. The first step in doing something about it is knowing about it.”
Some birds were especially hard hit, including common ones. The study found that yellow-whiskered greenbul (Eurillas latirostris) populations dropped by 73 percent in the forest. The icterine greenbul (Phyllastrephus icterinus) fared even worse with a population drop of 90 percent. Both of these species are currently considered Least Concern by the IUCN Red List due to a large range across Africa. But declines were across the board.
“Logging and associated disturbances that have been taking place in Ghana’s forests appear to have affected the entire bird community – including both common and rare or specialized species – causing abundance declines across species,” said Arcilla. “Species that were already rare are then most vulnerable to local extinction following logging, and many ‘common’ species have become much less common.”
Interestingly, the study found that logging actually hit forest generalist birds harder than forest specialists, the opposite of what researchers expected.
The researchers write that this is “an example of the difficulty predicting specific impacts of logging in any particular system or region a priori, without collecting empirical data.”
Arcilla told Mongabay that one reason behind the decline in generalists may be their ability to survive on forest edges. According to Arcilla this brings them in closer contact with local people – and threats like hunting and logging.
“The edges of Ghana’s forest fragments are typically surrounded by high density villages, and under intense pressure from human activities,” explained Arcilla. “Many residents hunt birds, even the smallest songbirds. Logged forests and smaller fragments are also likely to have more human disturbance from hunters, illegal loggers, and other people exploiting the forest and wildlife, because they tend to be more accessible by road or footpath.”
In addition to a loss in abundance, the study also documents the decline in species diversity, with some birds vanishing from the forest altogether. In all, the team documented 46 bird species, while an earlier study had counted 82 species.
“Although it’s difficult to ‘prove’ absence or extinction without exhaustive surveys, it is likely that some of these species are either extremely rare or possibly extinct in Ghana,” Arcilla told Mongabay.
She added that she believes the effect is not limited to birds.
“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 paper recommends that Ghana increase measures to protect these forests from illegal logging, including more forest rangers, law enforcement, and adding road blocks to logging roads to frustrate illegal loggers.
Protection of Ghana’s forest, Arcilla said, must “begin with adequate law enforcement.”
She added, “some in Ghana have even called for Ghana’s military forces to be tasked with bringing a halt to illegal logging. In the long term, well-supervised, well-supported law enforcement staff could patrol the 92% of Ghana’s forest that comprise forest reserves, as they already do in the other 8% of Ghana’s forests designated as national parks and other wildlife protected areas. Anti-poaching patrols in Kakum National Park and Ankasa Resource Reserve, for example, have been effective not only at controlling poaching but also keeping illegal loggers and other illegal actors out of forests.
“Protecting Ghana’s forests is entirely possible with sufficient support.”
Policy reform of industrial logging is also needed, according to the researchers. One of the most important would be finding legal solutions to supply the domestic timber market, rather than penalizing the domestic timber industry.
“Current forestry laws, which do not provide sufficient domestic timber to meet demands and impose a 20% duty on wood imports, are widely viewed as unfair,” Arcilla explained. “This and the lack of law enforcement contributes to perverse incentives fueling illegal logging as a cheap, easy alternative to buying legally logged wood or artificially expensive wood imports.”
According to Arcilla, innovative conservation programs, including payments that are “conditional upon conservation success,” could go a long way toward solving the country’s forest crisis.
“As the last refuges of its forest wildlife, Ghana’s forest reserves are incredibly valuable – arguably much more valuable standing than logged and destroyed,” Arcilla said. “Much needed jobs for law enforcement staff could be provided through direct payments to conserve biodiversity, a system in which financial incentives, are provided by donors in return for conservation outcomes…If [locals] can benefit more from protecting forest than destroying it, they will protect it.”
The researchers noted that the wildlife of Ghana doesn’t have long to wait.
“Ghana’s remaining forests are a living monument to Ghana’s unique natural and cultural heritage,” Arcilla said. “Standing up to the current forestry crisis would help restore pride in these treasures, home to African elephants, grey parrots, unique primates, and many other charismatic and unique wildlife species.
“Ghana would take back its future from illegal loggers and set an example of what is possible for other tropical forest countries in Africa and around the world.”
- Arcilla, Nicola, Lars H. Holbech, and Sean O’Donnell. “Severe declines of understory birds follow illegal logging in Upper Guinea forests of Ghana, West Africa.” Biological Conservation (2015).