A brief guided tour of the Lake Magadi study design via maps.
(1) Base Map – This is the basic map of the study site in Kenya’s southern Rift Valley. Lake Magadi is at the far east and the Nguruman escarpment is along the western border. The swamp is fed primarily by the Ewaso Ngiro river (center) and drains into Lake Natron to the south.
(2) Bomas – Brown points indicate Maasai bomas (homes + livestock pens). The Conservation Area, in which bomas are not allowed, lies to the south of the dry Sampu riverbed and east of the swamp. The remaining area is grazing land used by the local Maasai, many of whom migrate seasonally.
(3) Dens – Striped hyena moms frequently move cubs to new dens, especially when the cubs are very young. The majority of dens are in thick bush and are very difficult to observe. To our surprise (and delight), two hyenas (mother and adult daughter) shared a den for 2 of their litters.
(4) Trail Cameras – We deployed motioned activated cameras across a grid to help monitor hyenas. To collect DNA samples from striped hyenas we otherwise might not work with, we coupled cameras with sticky hair snares on scented rubbing posts that snares passively collect DNA samples.
(5) Transects – We used nighttime driving transects (heavy dashed lines) to evaluate the distributions of prey species on which the hyenas rely (e.g. gazelles) and the other carnivore species which can compete with striped hyenas for food (e.g. spotted hyenas), or displace or kill striped hyenas (e.g. lions).
(6) Combining Methods – Our monitoring schemes are a good example of how we designed the study to simultaneously approach questions from multiple angles: transects bisected camera grids so that transect data (prey distributions) complemented camera data (predator distributions) and vice-versa.
(7) The Grid and the Hyenas – We also designed the camera grid to encompass the areas used by the striped hyenas we monitor directly (individuals indicated here by different colored points). This ‘fit’ allowed us to relate their activities to those of the other carnivores we monitored via the cameras.
(8) The Transects and the Hyenas – As with the camera grid, basing transect coverage on the ranges of the striped hyenas we monitor directly (individuals indicated here by different colored points) allowed us to evaluate the relationship between changes in prey distributions and densities and striped hyena activities.
(1) Base Map - This is the basic map of the study site in Kenya's southern Rift Valley. Lake Magadi is at the far east and the Nguruman escarpment is along the western border. The swamp is fed primarily by the Ewaso Ngiro river (center) and drains into Lake Natron to the south.