Measuring threats to Budongo’s reptiles and amphibians

Above: Olive house snake in the Budongo Forest taken by T.Doherty-Bone.

I first visited Budongo Conservation Field Station, back in 2012 with the hope of starting a project for amphibians and reptiles there. Over several weeks I worked alongside BCFS field assistants exploring the forest, searching for frog, snake, lizard and tortoise species. As well as getting our own quantitative baseline for the amphibians of the forest, we did the same for areas cleared for agriculture. During my visit, the field assistants were trained to continue surveying for amphibians on a seasonal basis after I left. During my doctoral studies, I managed to get back during a Christmas break to check on how things had progressed. Although a lot of data had been gathered, it was becoming apparent that the current survey methods would not be enough to allow us to clearly understand the habitat requirements of the amphibians of Budongo. We decided to start identifying sections of the forest that could be used in a more intensive survey. Following another two week trip, we ended up with a portfolio of study sites that would allow us to make a stratified, replicated study of the impacts of forest management history on amphibians in the forest.

In April of this year, we set aside three whole months to regularly survey 20 sites across the forest-farm landscape. We used fixed transects, so that they can be revisited in future with minimal bias to the comparisons. The diligent support of the staff at BCFS made this possible, patiently transporting us to some of the more remote sections of forest, not accessible by foot from the field station. This extended beyond just field work and I was also extremely grateful to the team for delivering me to the hospital when I came down with a fever (might have been typhoid!). With limited time available to complete the project, we managed to survey all transects on three separate occasions. We also measured the structure of the forest so that we could understand any differences or similarities of amphibian community structure. So far we have found forests that are continually exploited to have a greater understorey plant density, fewer big trees, fewer fallen logs and deeper leaf litter.

Above: Golden puddle frog in the Budongo Forest taken by T.Doherty-Bone.

Frog species within the Budongo forest include tree frogs, Ruwenzori clawed frogs, squeaker frogs, golden puddle frogs while in the farmland were reed frogs, savanna puddle frogs, Mueller’s clawed frog. River frogs were in both land use types, all that was needed for them was (strangely enough) a river. We kept our eyes out for reptiles to see if forest management impacted them, but we did not see enough to make this assertion, other than rainbow lizards are likely to move in when the forest has been completely cut down, but if there is still a canopy (i.e. only slightly cut down), they don’t seem to fancy it. And a baby Nile Monitor was hiding in the walls of the field station. These lizards can get up to 6ft in length! The previous visits were not so lucky to meet many snakes, but as we had more time, we met at least one snake a week, usually a different one each time. These included powdered tree snakes, green tree snakes (there are several kinds*), house snakes, bush vipers, forest cobras – not all of these are dangerous, but capturing a snake has to happen quickly but also with great care. For example, on meeting a snake, one will have to restrain it with a stick (usually a purpose built snake stick) and then have a careful look as to what one has captured. There are lots of harmless green snakes in the forest, but only a couple are dangerously venomous, such as the Jameson’s mamba and the boomslang.

Above: Baby Nile monitor lizard hiding in one of the Budongo Field station lodges taken by T.Doherty-Bone.

One reptile group we have been struggling to work on are turtles and tortoises. We did manage to see a mud turtle out in the farms, however we did not encounter the elusive forest tortoise ourselves personally. Thankfully, the Budongo Forest is home to several other researchers and conservation workers, so we put out a memo to report any tortoise sightings so we could work out when and where they are most frequently seen. Forest Tortoises are an under-studied animal in Africa, possibly because they are so elusive – the odd one gets seen from time to time, but the best way to study them is to put on a radio-tracker on one during a serendipitous encounter. What we do know is that they are dependent on forest, and aside from deforestation, they are severely hunted throughout their range. My only previous sighting of a tortoise in Africa over the past 13 years has been hanging from a rope at the side of a road, being sold for bushmeat. The IUCN lists it as Data Deficient, but it has been argued that it could be listed as Critically Endangered given its likely range reduction. This nominal species is likely to consist of several cryptic species, which are likely to be even more threatened. But from the time being, the tortoises at Budongo appear to be okay, if not rare, and we have started to break the ground on understanding them in this forest.

Aside from our target organisms (amphibians and reptiles), the biodiversity of Budongo forest is amazing rich with wildlife. Our study could easily have focused on ants or on millipedes or on birds, even primates. However the “crawlies” always have my attention, the memorable encounters being with army ants, dung beetles, forest crabs and my favourite being a whip Scorpion carrying its babies on its back.

Above: Marching ants carrying dead termites, Below: Female whip scorpion with young on her back. Photos by T.Doherty-Bone.

Working around the Budongo Forest and surrounding areas, we sadly witnessed several threats to the forest. Moving away from the field station, we frequently found trees being cut down illegally, even bumping into nervous looking tree poachers who often turned and ran. We sometimes came upon snares, at one point we had to rescue a blue duiker from a snare that was strangling it as it ran about forest with the pole dislodged. Snares are an increasingly rare occurrence near to the field station, demonstrating the value of it’s presence alone, with regular forest excursions by researchers following primates around – it deters illegal forest users. Even if a researcher is only interested in primate facial expressions, their presence in the forest still protects it. Although we focused just one animal group,  our work this year has helped us quantify the substantial benefits of protecting the Budongo Forest.

Until next time

Thomas

RZSS Co-ordinator, Conservation Research and Action for Amphibians of Uganda and Camaroon