Camera Trap Study Offer View of Declining Mammal Populations
Imagery from three continents, seven countries highlights importance of protected areas & coordinated approach to mammal conservation and diversity
Arlington, VA — The first global camera trap mammal study, announced today by a group of international scientists, has documented 105 species in nearly 52,000 images, from seven protected areas across the Americas, Africa and Asia. The photographs reveal an amazing variety of animals in their most candid moments — from a minute mouse to the enormous African elephant, plus gorillas, cougars, giant anteaters and — surprisingly — even tourists and poachers.
See the images from the camera traps: Photo Gallery 1 | Photo Gallery 2
Analysis of the photographic data has helped scientists confirm a key conclusion that until now, was understood through uncoordinated local study: habitat loss and smaller reserves have a direct and detrimental impact on the diversity and survival of mammal populations. Impacts are seen in the form of less diversity of species and less variety of body sizes and diets (smaller animals and insectivores are the first to disappear), among others. This information replicated over time and space is crucial to understand the effects of global and regional threats on forest mammals and anticipate extinctions before it is too late.
The results of the study have been published in the article "Community structure and diversity of tropical mammals: data from a global camera trap network", in the journal Philosophical Transactions of the Royal Society. The study was led by Dr. Jorge Ahumada, ecologist with the Tropical Ecology Assessment and Monitoring (TEAM) Network at Conservation International. Protected areas in Brazil, Costa Rica, Indonesia, Laos, Suriname, Tanzania and Uganda were researched, making this not only the first global camera trap mammal study, but also the largest camera trap study of any class of animals (not just mammals).
To gather data, 420 cameras were placed around the world, with 60 camera traps set up in each site at a density of one per every two square kilometers for a month in each site. After photos were collected from 2008-2010, scientists categorized animals by species, body size and diet, among other things. They found that larger protected areas and continuous forests tend to contain three similar attributes:
- a higher diversity of species
- a greater variety of animal sizes, including populations of larger mammals
- a greater variety of diets among those mammals (insectivores, herbivores, carnivores, omnivores)
"The results of the study are important in that they confirm what we suspected: habitat destruction is slowly but surely killing our planet's mammal diversity" said Dr. Ahumada. "We take away two key findings from this research. First, protected areas matter: the bigger the forest they live in, the higher the number and diversity of species, body sizes and diet types. Second, some mammals seem more vulnerable to habitat loss than others: insect-eating mammals — like anteaters, armadillos and some primates, are the first to disappear — while other groups, like herbivores, seem to be less sensitive."
Of the sites researched, the Central Suriname Nature Reserve presented the highest number of species diversity (28) and the Nam Kading National Protected Area in Laos presented the lowest number of species diversity (13). The body size of species photographed ranged from 26 g (Linnaeu's Mouse Opossum, Marmosa murina) to 3,940 kg (African elephant, Loxodonta africana).
With around 25 percent of all mammal species under threat and little global quantitative information available, this study fills a very important gap in what scientists know about how mammals are being affected by local, regional and global threats such as overhunting, conversion of land to agriculture and climate change.
"What makes this study scientifically groundbreaking is that we created for the first time consistent, comparable information for mammals on a global scale setting an effective baseline to monitor change. By using this single, standardized methodology in the years to come and comparing the data we receive, we will be able to see trends in mammal communities and take specific, targeted action to save them", said Dr. Ahumada, adding that since 2010 cameras have been installed in new places, expanding the monitoring network to 17 sites (Panama, Ecuador, another site in Brazil, two sites in Peru, Madagascar, Congo, Cameroon, Malaysia and India). "Without a systematic, global approach to monitoring these animals and making sure the data gets to people making decisions, we are only recording their extinctions, not actually saving them."
Mammals serve as indicators of ecosystem health and play important roles in nature that ultimately benefit people, such as plant growth control, nutrient cycling and seed dispersal. For instance, some scientists argue that the removal of large mammals through excessive hunting reduces the capacity of forests to store carbon, since those animals are responsible for the dispersal of large, high carbon density seeds. Forests decreased capacity to store carbon means decreased capacity for people to alleviate the effects of climate change.
"We hope that these data contribute to a better management of protected areas and conservation of mammals worldwide, and a more widespread use of standardized camera trapping studies to monitor these critically important animals," concluded Dr. Ahumada.
The Tropical Ecology Assessment and Monitoring (TEAM) Network is a partnership between Conservation International, The Missouri Botanical Garden, The Smithsonian Institution and the Wildlife Conservation Society, and partially funded by these institutions and the Gordon and Betty Moore Foundation.
Local Partners in the study are: Instituto Nacional de Pesquisas da Amazonia (INPA), Conservation International Suriname, Organization for Tropical Studies, Museo Tridentino di Scienze Naturali, and Institute of Tropical Forest Conservation.
- Americas, Africa and Asia
- Seven sites:
- Bwindi Impenetrable Forest (Uganda)
- Udzungwa Mountains National Park (Tanzania)
- Bukit Barisan Selatan National Park (Indonesia)
- Nam Kading National Protected Area (Lao PDR)
- Central Suriname Nature Reserve (Suriname)
- Manaus (Brazil)
- Volcan Barva Transect (Costa Rica)
- 420 cameras used
- 60 cameras in each site
- 1 camera every 2 square kilometers
- Cameras were set up for a month in each place
- Timeframe of data analyzed in the paper: 2008-2010
- Number of sites being monitored today: 17
All data from the study is publicly available at: www.teamnetwork.org/en/data/query
About Conservation International (CI):
Building upon a strong foundation of science, partnership and field demonstration, CI empowers societies to responsibly and sustainably care for nature, our global biodiversity, for the long term well-being of people. Founded in 1987, CI has headquarters in the Washington, DC area, and nearly 900 employees working in more than 30 countries on four continents, plus 1,000+ partners around the world. For more information, visit www.conservation.org and follow us on Twitter: @ConservationOrg or Facebook