Only an estimated 3,200 tigers remain in the wild worldwide. Image credit: Wildlife Conservation Society
Unfortunately, assessing the problem is not easy; most biodiversity studies are forced to rely on secondary and retrospective data. To fill this gap, the Wildlife Conservation Society, in conjunction with other groups, has built the Wildlife Picture Index, a global network of camera traps used to assess the health of medium and large-sized terrestrial birds and mammals.
The steenbok, seen here, is a small antelope native to East Africa. Image credit: Wildlife Conservation Society
The project seeks to survey entire landscapes, focusing on the most wide-ranging species in each area. Such studies typically require expensive instruments and regular airplane flyovers. The Wildlife Picture Index has been able to achieve the same results with a network of motion-triggered autonomous cameras.
The aardwolf is a type of hyena native to Africa that feeds almost entirely on insects. Image credit: Wildlife Conservation Society
When an animal walks past a camera, the shutter snaps and the image is uploaded into a virtual photo album containing hundreds of other photos. Statistical analysis of the photos allows researchers to draw conclusions about the biodiversity of the area.
The project places 100 camera traps for every two square kilometers of habitat.
The aardvark roams across sub-Saharan Africa. Image credit: Wildlife Conservation Society
And already, the program is yielding results. In Sumatra, Indonesia, an analysis of 5,450 images suggests a net biodiversity decline of 36 percent over the past eight years. This means that in the forests of Indonesia, wildlife loss is outpacing rates of deforestation.
The analysis also revealed that animals with a high value on the black market were disappearing faster than those typically hunted as a nuisance or for subsistence.
These insights, researchers say, are valuable for crafting conservation plans in the future.
Frequently mislabeled as scavengers, the spotted hyena acquires most of its food by hunting ungulates. Image credit: Wildlife Conservation Society
Tim O'Brien, a researcher from the Wildlife Conservation Society who is leading the study, explained:
The Wildlife Picture Index is an effective tool in monitoring trends in wildlife diversity that previously could only be roughly estimated...this new methodology will help conservationists determine where to focus their efforts to help stem the tide of biodiversity loss over broad landscapes.
Less than 300 Sumatran rhinoceros survive in the wild. Image credit: Wildlife Conservation Society
John Robinson, executive vice-president for conservation at WCS, commented:
The Wildlife Picture Index will allow conservationists to accurately measure biodiversity in areas that previously have been either too expensive, or logistically prohibitive...we believe that this new methodology will be able to fill critical gaps in knowledge of wildlife diversity while providing much-needed baseline data to assess success or failure in places where we work.
The leopard is considered "near threatened" because of its rapidly declining range. Image credit: Wildlife Conservation Society
The caracal is a medium-sized cat that rages across Western Africa. Image credit: Wildlife Conservation Society
The system has also led to some unexpected results: Conservationists "rediscovered" the Sumatran short-eared rabbit—which hadn't been seen in more than 80 years—thanks to a photo captured by the camera traps.
The population of wild lions has decreased 30-50 percent in the last two decades. Image credit: Wildlife Conservation Society
The project was designed to address a mandate put forth by the Convention on Biological Diversity to develop indicators for reliably monitoring biodiversity. It has demonstrated, however, a new way of approaching conservation research—one that may help preserve biodiversity worldwide.