The KNP Is Alive...With The Sound of Croaking
If the colourful world of amphibians interests you as a subject for photography or nature-gazing, then the Kruger National Park (KNP) is the place to be this season. Tourists often wax poetic about the Big Five, but frogs have an equally important function in maintaining the ecological balance in South Africa’s most important national parks. The good news is that our favourite amphibians are fulfilling their functions splendidly, as the results of an important three-year study, carried out by the Water Research Commission (WRC) indicate.
Frogs and local ecosystems
The study, headed by independent researcher, Dr. Wynand Vlok, reveals that the KNP is literally teeming with frogs and this is good news for the area as a whole, since frogs function as an ‘indicator’ species, their presence or absence being tell-tale signs of the health (or lack thereof) of a particular ecosystem.
South Africa is home to approximately 130 different frog species, yet a third of these are in danger of extinction. On a global level, the situation is no less alarming, with frogs swiftly hopping their way into Top 10 Endangered Species lists in various countries. Various reasons have been postulated for the worrisome trend, including habitat loss, pollution (air and water), increased ultraviolet radiation, pesticide use, predation and climate change. Another important reason is an incurable fungal disease known as chytridiomycosis, said to be responsible for the greatest disease-causing loss of biodiversity in history. Climate change, which affects aquatic systems particularly harshly, is also to blame. Wetlands are said to be the most affected ecosystems.
The WRC study surveyed 45 wetlands at the KNO, as well as the Letaba, Olifants, Luvuvhu, Sabie and Crocodile rivers. Over 30 species of frogs were identified, several of which were new species. Species spotted included the Southern Ornate Frog, the Sharp-Nosed Grass Frog and the African Bullfrog. Scientists also found the tadpole of a new species known as the East African Puddle Frog.
The reason for the surge in numbers can mostly be attributed to recent flooding in the area, which wreaked havoc on bridges, homes and roads, but which were manna from heaven as far as the frogs are concerned. The study also focused on the effect of acid rain and declining pH levels on frog numbers. Researchers carried out acid tolerance tests on eggs and tadpoles of four different tadpole species found in the KNP, concluding that pH levels have a definite impact on tadpole size and development. As early as 2000, studies proved that low pH levels reduce the survival and activity level of frogs. Therefore, while the thriving frog populations are a good sign for the health of the aquatic ecosystems in the KNP, these populations will require continuous monitoring, since acid rain continues to pose a serious threat to their continued survival; indeed, it is as yet unknown how long the soil in these areas can continue to successfully buffer high levels of acidity.
Visiting the Amphibians… and more, at KNP
For many tourists from all over the world, their dream holiday involves coming into contact with the Big Five while visiting the KNP and most often, they are not disappointed. The KNP houses approximately 1,500 lions, 12,000 elephants, 1,000 leopards, 5,000 rhinos and 2.500 buffalos, as well as striking plant species, including the baobab, natal mahogany and monkey orange trees. A safari is somehow one of the most adventure-packed yet safest holidays, requiring little more than a standard travel or health policy and offering a host of economical ways to get the most out of your visit – there are membership cards, for instance, which allow you to visit most of South Africa’s premier conservation areas for as little as R300 (around $30 US). There are various boat and canoe adventures that will allow you to see the colourful frogs and tadpoles in their natural habitat, and if you’re feeling more adventurous, you may decide to check out dangerous reptiles such as the black mamba snake, with the help of experienced handlers who will ensure you’re adventurous spirit is kept within reasonable bounds! And if a trip is out of the question, you can always take a virtual safari by contemplating the wildlife on Africam.
A Guide for Frog Spotting the Top Three at the KNP: If you’re undertaking a trip to South Africa, watch out for the following gorgeous frog species:
The Southern Ornate Frog (Hildebrandtia ornata): A medium-sized, plum frog with a broad green/brownish vertebral band running from the snout to the end of the body. The band can either cover the entire snout or divide into three separate stripes, the middle of which runs to the end of the body.
The Sharp-Nosed Grass Frog (Ptychadena oxyrhynchus): This frog easily blends into the background, since it is mottled brown and grey in hue. It has a pale triangle on its snout and a white-and-pale yellow underbelly. It is easily recognised by its high-pitched trill, which it repeats two or three times per second.
The African Bull Frog (Pyxiecephalus adspersus): One of the largest frogs in Africa as a whole, the African bullfrog can reach up to 24cm (9.5 inches) in size! It is plump and olive green, and has bumpy, rough skin. Males normally have a yellow-hued throat, which is cream-coloured in females. This frog’s hind toes are webbed.