Croaking in the Cloisters

The endangered Kloof Frog, Natalobatrachus bonebergi, originally discovered near Mariannhill, is restricted to forest streams in KwaZulu-Natal and the Eastern Cape

So named for its discovery in the kloofs of Mariannhill in 1912, by Abbot Boneberg from the Mariannhill Monastery, the Kloof Frog, Natalobatrachus bonebergi, is a very unique species of frog – it is the only species in its genus, a fairly rare occurrence known as monotypic (Homo sapiens is also monotypic, having killed off the competition!). In other words, it is genetically distinct enough from other species to be placed in its own group. It is also an Endangered species, according to the IUCN Red List (International Union for the Conservation of Nature) which provides an assessment of species’ risk of extinction. The IUCN Red List measures the pressures acting on species, which guides and informs conservation actions to help prevent extinctions. This is why the IUCN Red List is often referred to as a Barometer of Life. Endangered is classified as species that possess a very high risk of extinction as a result of rapid population declines of 50 to more than 70 percent over the previous 10 years.

In the case of the Kloof Frog, this assessment is a result of the limited geographic distribution in which the species is found – it is restricted to lowland riparian forest patches between Manubi State Forest Reserve in the Eastern Cape Province, to southern and central KwaZulu-Natal. Its elevational range is between 50 and 900m asl. Within this fragmented landscape, its area of occupancy (AOO) is just 188 km2. As the species is so tied to riparian forest, much of its habitat has been historically lost to sugarcane cultivation and other agriculture, woodcutting, afforestation and urbanization, all of which are ongoing threats to the subpopulations of KwaZulu-Natal Province. Mining of the Marble Delta in in the Oribi/Port Shepstone area is also likely to have caused, and continues to cause, direct habitat loss. It is also threatened by pollution and siltation of streams. An emerging threat includes alien invasive vegetation.

Kloof Frog habitat – slow-flowing streams with overhanging forest vegetation

It is a habitat specialist, inhabiting rocky streams in dense scarp and gallery forests, where it is usually found close to water, and does not occur in open areas. The species is a semi-arboreal specialist, requiring clear shallow streams with overhanging vegetation and large rocks for egg clump attachment. They are also good swimmers and are well camouflaged in their environment of leaf-litter and rocks. They have an extended breeding season from August to June, peaking between December and April. Males have a very quiet click call which they issue from the riverbank or elevated positions on rocks or vegetation above the water. They are often active during the day, unlike most frogs.

The reason for this very specific choice in habitat selection is that the Kloof Frog has an unique breeding behaviour, in particular egg laying. Females deposit distinct gelatinous masses, consisting of 75–95 eggs on rock surfaces or vegetation (leaves, twigs or branches) overhanging pools. Many species of frogs have a high level of parental care, and the Kloof Frog is a good example of this. Females will remain close to their egg clump and have been observed keeping the egg clutches moist with liquid from their cloacas. Tadpoles hatch after about six days and drop into the water to complete development, which takes approximately two months.

The unique egg clump of the Kloof Frog, which can be attached to leaves, twigs, branches or rocks

Kloof Frog tadpoles in egg jelly

Photo: Nick Evans

As a result of these very particular habitat requirements, and loss of habitat elsewhere, the species is found mostly within protected areas, populations are mostly restricted to streams within protected areas. Locally, small populations can be found in Krantzkloof Nature Reserve, Springside Nature Reserve and several Conservancy areas in Hillcrest, Waterfall, Gillitts and New Germany. Many of these confirmations of sightings have taken place in recent years. We encourage the public to submit their sightings via platforms such as i-Naturalist, and in particular projects such as AfriHerps.

While the frog occurs in ‘Protected Areas’ often the management, particularly around stream health, is lacking in these reserves, and improved management is a key intervention needed for the species. Siltation and alien vegetation are some of the major threats entering reserves as a result of development activities taking place outside the reserve boundary. More stringent measures need to be put in place to mitigate siltation, especially from housing and shopping developments. For example, construction of the Checkers centre in Gillitts resulted in a huge amount of siltation entering downstream Crowned Eagle Conservancy, which has been magnificently looked after by the George brothers, Mervyn and Clive (and featured in the Conservancies KZN series of Walks on the Wild side event in March 2021). The discovery of the Kloof Frog here is a happy story, with the site being inspected several years ago as part of an application to develop a new road adjacent to Stockville Road. Consultant Ryan Edwards observed the Endangered Kloof Frog here, and along with the discovery of several other threatened species such as a pink-footed millipede, the construction of the road was fortunately prevented. We cannot continue to view “progress” as those activities that harm the environment. Indeed, if the last two years have taught us anything, it is that without intact, functional habitats, human health is in jeopardy.

Kloof Senior Primary learners with Jeanne monitoring Kloof Frogs at Crowned Eagle Estate

Towards improving such management, and facilitating research on the Kloof Frog, the Endangered Wildlife Trust, with support from Ezemvelo KZN Wildlife, have monitored several populations of the Kloof Frog over the past seven years. Starting in 2013, with the development of a monitoring protocol that focusses on the egg clumps as the main variable as an indicator of breeding activity and population health, we have rolled out monitoring at several Kloof Frog sites. These include Vernon Crookes Nature Reserve on the KZN south coast, Crowned Eagle Estate in Gillitts, and several reserves in the Eastern Cape province. The protocol includes data collection on number of egg clumps within a stretch of stream, number of eggs per clump, egg-laying surface, water-depth below egg clump position and height of egg clump above water surface. Initially, this monitoring was done monthly for several years and is now carried out in December and April (the start and end of the peak breeding season). We have also developed a digital app to aid the collection of this data – much easier than bits of soggy paper! Vernon Crookes provides our most long-term and consistent database, but the surveillance was also carried at Crowned Eagle Estate in a joint citizen science effort by Thomas More College and Kloof Senior Primary School.

Citizen Science can be fun!

Citizen Science contributions are critical to research and conservation. Given the limited resources for conservation, in particular for amphibians, any help we can get in improving the knowledge base is welcome. Especially important are contributions of occurrence records, which is becoming much easier with platforms such as iNaturalist. All records are verified, and these are then incorporated into, for example, Red List assessments, spatial planning processes and a revised Frog Atlas. So, keep an eye out for egg clumps and frogs next time you are out and about!

Our findings from the monitoring show that breeding takes place across many months of the year, including in winter months, however the peak is very much tied to summer rainfall – during the drought experienced in 2015 and 2016, breeding activity was very much reduced. The most preferred egg attachment surfaces are leaves, followed by branches and then rocks. Egg clumps can be attached anywhere between 10cm and 2m above water, with a preference around 1.5m. The egg clumps are usually laid in dabbled shade.

Cherise Acker of EWT conducting camera trap monitoring of the Kloof Frog, which has revealed some interesting behaviours!

Taking this a step further, and given the unique behaviour of Kloof Frogs, the Endangered Wildlife Trust embarked on the use of camera traps for observing the species. To our knowledge, the is the only camera trapping of frogs that has been done in South Africa, and possibly Africa. We set up a camera trap at a known egg deposition site (in front of a large rock) in Vernon Crookes in 2020 to take time-lapse images. The findings have been fascinating and have revealed interesting behaviours, including site inspections by male and female pairs prior to egg laying, frequent visitations by busy mum frog – less so during wet weather, confirming that she plays a role in keeping egg clumps moist, and male frogs gathering in small groups and just hanging out. Sound familiar?! We have been able to track movement of the frogs over time, as well as observe interactions with other species, for example when big Mr River Frog arrives, the Kloof frogs scatter. We plan to expand this work to other sites where the Kloof Frog occurs.

Artist Giffy Duminy with mural at Iphithi Nature Reserve

An extremely important part of our work is being able to share it with the general public, and to make sure that people understand that healthy ecosystems, including with thriving frog populations, is also good for human health. We may lose sight of this, but protecting our wild spaces, and doing what we can at home to this end (see below) is of vital importance if future generations – of both humans and frogs – are to persist. An exciting campaign held in 2020, as part of our annual Leap Day for Frogs awareness day, was working with the incredibly talented street artist, Giffy Duminy, who, along with other local artists, and with support from the Kloof Project, painted a series of Kloof Frogs at Elizabeth Bridge in Kloof – if you haven’t spotted them, and the other beautiful murals that have since joined them, slow down next time you drive past. At the annual Kloof Conservancy Frog Day, Giffy also painted a mural at Iphithi Nature Reserve in Gillitts as part of this campaign.

Painted Reed Frog by Robyn Ansell

Communicating conservation through art is a great way to connect people to nature and inspire getting out there to see the real-life versions. We have also recently partnered with the wonderful local artist, Robyn Ansell, who has done a beautiful series of frog paintings, available as prints, card and gift tags. Look no further for you next birthday or festive season needs!

Conservation projects cannot be successful if done in isolation. Our work on the Kloof Frog, as well as other threatened species across South Africa, is possible due to strong and long-term collaborations. Our thanks go to Ezemvelo KZN Wildlife and their Honorary Officers, Kloof Conservancy, Crowned Eagle Conservancy, and our donors, without whom our work would not be possible. To join one of our frogging events, or host one in your local area, please do not hesitate to contact me at jeannet@ewt.org.za.

Kloof Frog

About the author

Dr Jeanne Tarrant

Bachelor in Zoology (2001) Rhodes University, South Africa, Masters in Environmental Science (2008) and Phd in Zoology at North-West Univeristy, Potchefstroom, South Africa. Jeanne manages the Endangered Wildlife Trust’s Threatened Amphibian Programme (TAP in South Africa).

This is the only NGO with a focus on frog conservation, using threatened species as flagships to:

• protect the critical freshwater and terrestrial habitats 
• improve the management of important amphibian habitat
• use research to monitor species and habitats to support conservation action
• promote behavioural change that reflects increased knowledge and recognition of the importance of frogs and their habitats.  

Jeanne is responsible for project design and coordination, specialist knowledge, partner and donor relations, fundraising and project management. Almost all of her work is linked to threatened frog species, which are usually associated with very limited distribution ranges and specific habitat types, most of which are not protected or well-managed. In 2020, Jeanne was recipient of the Whitley Award, or “Green Oscar” for her work in conservation.

Fun facts: I took up mountain biking at age 40, I try to find time for yoga regularly, I increasingly love gardening and getting grubby! I have two boys, who get very upset if I don’t catch the snakes spotted in the garden for them if they are not around!  Favourite amphibian: Kloof Frog, Natalobatrachus bonebergi – they are handsome little frogs that have a unique egg-laying technique – attaching them to branches or rocks above water, females then watch over them.

Twitter: JeanneT4Frogs, #FrogLady

Youtube: English, some Afrikaans and isiZulu