‘The Serengeti ecosystem is incredibly diverse and dynamic, and home to one of the largest mammalian migrations on earth,’ says Alexandra Swanson, from the Department of Ecology at the University of Minnesota, and lead author of the Snapshot Serengeti wildlife conservation survey.
‘We set out camera traps to collect data on where all of these animals were across the landscape, how many of them there were, and what they were doing,’ she continues. ‘We wanted to know how predators coexisted with other predators, given that they interact aggressively when they meet. We wanted to know how herbivores managed to coexist with each other given that they compete for the same resources. And we wanted to know how prey animals balanced their need for food with their need to avoid being eaten.’
Camera traps have become a common tool in monitoring conservation areas such as the Serengeti, helped by technological advances which have made them an extremely cost-effective way to track animals over a wild expanse.
‘We set the cameras up on a grid layout to ensure systematic coverage across the entire study area,’ says Swanson. ‘Every camera was placed as close as possible to the centre of a 5km2 grid cell – so the cameras were about 2.3km apart. At the centre of every grid cell, we picked the nearest tree that could support a camera and that had reasonable visibility across the landscape. Tall grass and branches can trigger the cameras to fire repeatedly, so we tried to minimise the risk of that happening.’
Overall, over 1.2 million images were taken by the 225 camera traps scattered across the Serengeti, of which 322,653 contained animals. A citizen science platform consisting of 28,000 registered volunteers subsequently sorted through the images to help catalogue each one, resulting in 48 different species being identified.
‘I think one of the coolest things about this publication is that volunteers – regular, everyday people with no formal scientific training – made this possible,’ says Swanson. ‘Even though computer algorithms are getting better, they can’t do what our volunteers did. So without the help of “citizen science” to classify all these images, this research would never have been possible. As technology allows researchers to collect increasing quantities of data, I think this type of citizen science participation will be increasingly important in generating scientific discovery.’
And her favourites? ‘In general, my favourite photos are the one that capture these animals at their most candid. Some of them are funny. Some are simply beautiful. But they all capture a side of the Serengeti that is otherwise so easy to overlook.’
‘This study is incredibly exciting because it provides some of the first systematic data on what all of these different species are doing day and night,’ adds Swanson. ‘And because the images can be used for so many ecological research questions, we’d like to keep the camera survey going for as long as possible, and expand outward. But we are limited by funding. In fact, if the Serengeti Lion Project, which provides the infrastructure for the Snapshot Serengeti survey, doesn’t find more funding soon, the survey will close down later in 2015.’