As public awareness about the plight of the world’s tropical forests has risen in recent decades, rainforests have become a frequent symbol of destruction and loss.
But there’s good news: New data collected by more than 1,000 camera traps across the tropics — and published today in the journal PLOS Biology — paints a more nuanced picture for the future of wildlife in these forests.
The research, based on data gathered by researchers with the Tropical Ecology Assessment and Monitoring (TEAM) Network, analyzed more than 2.5 million pictures taken in 15 protected areas across Latin America, Africa and Southeast Asia. Using sophisticated statistical methods that compile the camera-trap images to estimate the proportion of the forest occupied by a particular species, the study found that among the almost 250 ground-dwelling mammal and bird species monitored, 17% of the animal populations increased in number while 22% remained constant and 22% decreased. (The other 39% of species were not captured often enough on camera to make an informative assessment.)
The fact that the majority of species assessed did not decline is significant, especially given the number of pressures facing these animals, from habitat destruction and fragmentation to the illegal wildlife trade. It also indicates that protected areas are doing their job.
Started in 2002 by Conservation International (CI), TEAM has grown to a coalition that includes CI, the Wildlife Conservation Society and the Smithsonian Tropical Research Institute. Its data collection and analysis represents a milestone enabling scientists across the world to study and compare rare species across large areas of forest.
“Our study reflects a more optimistic outlook about the effectiveness of protected areas,” said Jorge Ahumada, executive director of TEAM and a co-author of the study. “For the first time we are not relying on disparate data sources, but rather using primary data collected in a standardized way across a range of protected areas throughout the world. With this data we have created a public resource that can be used by governments or others in the conservation community to inform decisions.”
Here are five species whose populations have either increased or stabilized — thanks in part to the parks where they live.
1. African golden cat, Uganda
After witnessing an initial decline in the occurrence of the African golden cat in Bwindi Impenetrable Forest, local researchers examined the data collected by TEAM and realized that the declines were occurring in areas of heavy tourism traffic. After park managers took advantage of this information and re-routed tourists to alternative trails, researchers began to see an increase in sightings of the African golden cat, which is listed as Vulnerable on the IUCN Red List of Threatened Species.
2. Great argus, Indonesia
The great argus is well-known for its remarkable courting display. Males clear an open spot in the forest and fan out their wings to reveal hundreds of “eyes” as they dance around for their potential mate; see if you can spot them when this bird walks in front of the camera.
Although this species is classified as Near Threatened by the IUCN Red List, our data indicates that it is showing signs of recovery in Bukit Barisan Seletan National Park. Although hunting by humans has influenced the species’ decline in the past, no humans have been captured on camera at this site since 2012, a possible indication that the birds are experiencing less pressure from hunting and habitat disturbance.
- How camera-trap data can help us predict earthquakes
- What camera traps reveal about how Colombian communities use forests
3. Jaguar, Brazil
Jaguars like this one — caught playing with its food on camera in Caxiuana National Forest — are either increasing or staying stable across the majority of TEAM sites; they remain listed as Near Threatened by the IUCN Red List. By using standardized methods, TEAM can provide not only a glimpse at how individual species are faring, but also a valuable look at overall forest health.
4. Bush dog, Ecuador
Bush dogs like the ones seen here in Yasuni National Park are extremely difficult to observe in the wild, but TEAM camera traps have captured this species at three different sites in South America, including the first-ever photographic evidence of the species in Peru’s Yanachaga National Park in July 2014. Although this species has not been observed at the third field site in the Central Suriname Nature Reserve since 2011, the results of the Wildlife Picture Index indicate that the overall status of this species is improving.
5. Asian elephant, Indonesia
Asian elephants like this curious individual were responsible for trampling a TEAM climate station two years ago in Bukit Barisan Selatan National Park. The population of this endangered species has been increasing in the park over the course of this long-term study. (An usually large group of elephants was also recently caught on camera in Cambodia’s Central Cardamom Protected Forest.) That is great news for the species — perhaps not so much for the climate stations.
Researchers caution that while this data is useful, it is only an estimation of trends in species populations; wildlife losses could still be occurring in the protected areas that were studied. In addition, this research does not speak for unprotected tropical forest areas, which may have higher rates of species decline due to differences in management and may be threatened by increased pressure from humans.
Molly Bergen is the senior managing editor of Human Nature.
Want to read more stories like this? Sign up for email updates. Donate to Conservation International.