New York, NY, 10 April 2024 — a new study reveals compelling evidence that forests certified by the Forest Stewardship Council®(FSC®) in Gabon and the Republic of Congo harbour a higher abundance of larger mammals and critically endangered species, such as gorillas and elephants, compared to non-FSC certified forests. The research was led by Utrecht University with support from WWF and the Wildlife Conservation Society (WCS), and was published in Nature on 10 April 2024. It underscores the effectiveness of measures implemented in FSC-certified forest concessions to safeguard wildlife. 

Key findings: FSC certification is a haven for larger mammals 
By meticulously documenting individual animal counts and strategically positioning camera traps, the research conducted by Joeri Zwerts affirmed that certified concessions notably harbour a larger population of large mammals – 2.7 times more for mammals over 100 kg, such as gorillas and forest elephants, and 2.5 times more for mammals between 30–100 kg such as leopards and chimpanzees, when compared to non-FSC-certified forest concessions. The number of smaller mammals observed was similar between FSC- and non-FSC certified concessions, painting a picture of less biodiversity in the latter forests. The effects were similar in both Gabon and the Republic of Congo. In addition, the encounter rates of large mammals in FSC-certified forests were comparable to published data from recently monitored protected areas in the Congo Basin. 

Clear link between hunting and biodiversity loss  
The research emphasizes the pivotal role of hunting in biodiversity loss, highlighting the reduced number of hunting signs and increased wildlife observations in FSC-certified concessions. Certified forestry entities’ proactive measures, such as blocking old logging roads, establishing checkpoints, and supporting alternative protein sources for local populations, have significantly curbed illegal hunting. 

Beyond wildlife conservation, the study highlights the broader positive impact of FSC certification. The conservation of large mammals positively influences seed dispersal, nutrient cycling, and forest carbon storage. Previous research (published in Nature Geoscience) has shown that tropical forests would potentially store 7% less carbon without the presence of elephants.  

Responsible forest management: an important pillar for biodiversity conservation 
The study shows how sustainable forestry practices can contribute to the conservation of large mammal populations and to the protection of existing tropical forests.

Said WCS research scientist and study co-author Fiona Maisels: “Tropical ecologists have known for some time that FSC certification is helpful for maintaining large-bodied mammal populations, based on studies that compare a single protected area to adjacent concessions. However, this is the first time that a set of paired FSC and non-FSC management concessions have been included in a carefully designed study over an enormous geographical area. The results are crystal clear: large animals of conservation concern (such as forest elephants and the great apes) are unquestionably far better off in FSC-certified forests.” 

This study – the first to compare so many different forest areas at the same time – “was a large and ambitious project that took five years and involved hundreds of local employees. We had to convince both certified and non-FSC-certified companies to participate in the study. It was hard work under challenging conditions, but the knowledge we gained will make an important contribution to the protection of animals in tropical forests,” said Utrecht University’s Joeri Zwerts, who led the study.  

Fran Price, Leader, WWF Forest Practice, said: “These results are inspiring and an indication that FSC continues to be an effective tool in tropical forests, and that its standards translate into tangible impacts. Solutions that benefit both people and nature do exist, and responsible forest management certification is one of those vital solutions. This study shows there is a significant difference between populations of large mammals, such as the critically endangered forest elephant, in FSC-certified concessions versus non-certified concessions. We urge companies to pursue FSC certification and invest more in research that can help inform continual improvement of such mechanisms.” 

Kim Carstensen, FSC International’s Director General said: “Utrecht University’s study reinforces FSC’s core principles and our commitment to responsible forest management. This research affirms the vital role of FSC certification in fostering diverse ecosystems and protecting endangered species in tropical forests, while benefiting both local communities and the environment.”  

As logging concessions account for more than half of the remaining forest areas in the two countries studied (61% in the Republic of Congo and 67% in Gabon), these positive results from FSC-certified concessions are of great importance for the conservation of biodiversity in the region.  

Methodology: rigorous surveillance unveils compelling insights 
Conducted by Joeri Zwerts and his team, the study published in the science journal Nature employed 474 camera traps across 14 logging concessions – seven FSC-certified and seven non-FSC-certified – in the Congo Basin. Over three to four years of fieldwork (two to three months monitoring period per concession) these traps snapped 1.3 million images, capturing approximately 55 mammal species including leopards and gorillas, as well as various endangered species.  

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