Heart of darkness revisited: rediscovery of four frog species in Itombwe Natural Reserve

Fieldwork in the Itombwe Natural Reserve , situated in the Eastern Democratic Republic of Congo, has led to the rediscovery of four species that were described before only by a Belgian herpetologist working in the fourties and fifties of the past century in this area. The Itombwe Plateau is an area which is characterized by a high degree of endemism and is one of the most important sites for amphibians in the whole of Africa. Beside describing the rediscovery of these four amazing frog species, the article provides insight into the very practical difficulties that field biologists and conservations face whilst working in parts of Africa that are still dominated by atrocities.

In the country profile of the Democratic Republic of Congo on the BBC website one can read the following: “A vast country with immense economic resources, the Democratic Republic of Congo (DR Congo) has been at the centre of what could be termed Africa’s world war. This has left it in the grip of a humanitarian crisis. […] Despite a peace deal and the formation of a transitional government in 2003, people in the east of the country remain in terror of marauding militia and the army.”

Thinking about Africa I always return to the books by Ryszard Kapuscinski who has written so beautifully about this continent and has witnessed firsthand 27 revolutions in the post-colonial era of the continent. Between the first discovery of these species in the fifties and the rediscovery the DR Congo has known many different leaders and wars, beginning with Patrice Lulumba as its first leader striving for freedom. In the aftermath of the murder on Patrice Lulumba, Kapuscinski was struggling for his life as he was a white man in a country surrounded by people who blamed the white man for the death of their hero Lulumba. Reading (his book the Soccer War) about the torturing he had to endure and his narrow escape from death, one can begin to imagine what it must be like to live in a country in a state of seemingly eternal warfare. And one cannot else but admire the perseverance of a reporter working under such harsh conditions but continuing to bring the news to the world. Not many have had the courage to do so.

The same holds for these researchers that have been doing their field work from 2008-2012 in an area where still no less than three armed military groups reside and where instability is still rather the rule than the exception. It is therefore very logical  that it has taken so many decades for biologists to rediscover these frog species in the eastern part of the DR Congo. But for researchers to go into the area and trying to uncover the biological richness is not that straightforward and we should be thankful for those who dare to venture there.

The Itombwe Natural Reserve forms part of the Albertine Rift of Central Africa, which in turn is the western montane branch of the Great Rift Valley. It runs from north of lake Albert in the eastern DR Congo to the southern tip of Lake Tanganyika. The Albertine Rift has been recognized as the most species rich area for vertebrates in continental Africa and has a high degree of endemism. The Itombwe Natural Reserve is a recently established (October 2006) protected area in the Albertine Rift on the western side of Lake Tanganyika. It is an area of approximately 15.000 km2 (almost half the land surface of the Netherlands) and ranges in elevation from about 900 to 3475 meters. It has a very diverse vegetation and is one of the few places in Africa where there is a complete succession of forest types from lowland rainforest to montane forest. The diversity of vegetation and habitats has to do with the great variety of temperature and rainfall throughout the Itombwe Mountains.

Next to being an important site for large numbers of endemic and threatened plants, butterflies, birds, reptiles, and mammals, the Itombwe Natural Reserve is one of the most important sites for amphibian conservation in Africa. This is illustrated by it having the highest number of endemic amphibian species (together with Virunga National Park) and unfortunately the highest number of threatened species in Africa.

Most of descriptions of species living in the Itombwe Natural Reserve date back to the fourties and fifties of the twentieth century when this part of Africa was still Belgian. It is no coincidence therefore that it was a Belgian scientist, Raymond Laurent, recording these species. He described several new species of frogs, among which the monotypic treefrog genera Callixalus and Chrysobatrachus, which is endemic to high-elevation grasslands. Ever since, there have hardly been any expeditions to this part of the world, so the status of these species has remained unknown for many decades. In 2011, the same researchers that have written this article, announced the rediscovery of five frog species in Itombwe Natural Reserve that hadn’t been seen since 1954. As a conclusion to their fieldwork in this area, they have now reported on the rediscovery of four species: Arthroleptis pyrrhoscelis(Arthroleptidae), Chrysobatrachus cupreonitens (Hyperoliidae), Hyperolius leucotaenius (Hyperoliidae), and Phrynobatrachus asper (Phrynobatrachidae). Fieldwork was conducted without the use of consistent methodology and consisted of a brief herpetological survey, due to the unsafe situation with several armed militia present.

Arthroleptis pyrrhoscelis was also recorded at the Kabobo Plateau, a relatively small highland area just southeast of Itombwe, which shares many characteristics and species with the Itombwe Natural Reserve. Based on analyses of amphibian specimens and DNA samples that these scientists have collected in both of the locations during their fieldwork from 2008 to 2012, they conclude that amphibian diversity is grossly underestimated in this region. Several new species that have been collected seem to have very restricted distributions and so there might be more awaiting discovery, also because these scientists haven’t ventured far into pristine forests, but found the amphibians mainly in already affected habitats.

The researchers recommend that the species be qualified by the IUCN as endangered, with Chrysobatrachus cupreonitens and Phrynobatrachus asper even deserving a critically endangered threat status. The latter species is hunted for food (and was rediscovered because it was offered to the scientists as food!) and for all species several threats are identified:  the ongoing deforestation in the area because of human pressure, the occurrence of the chytrid fungus in multiple species in the area, overgrazing of grasslands on the plateau and limited elevational distributions. The high degree of endemism means that we should be very careful with the conservation of these and other species, as we will find them nowhere else on earth.

There is also an interesting evolutionary story to tell about this region: the large number of endemic species suggests that the forests in the Itombwe Natural Reserve and the Kabobo Plateau have remained climatically stable for a very long time. Among those endemic species are even two monotypic genera, Callixalus and Laurentophryne, which are considered to be relictual lineages. These relict endemics are the sole survivors of their genera, probably because they could survive in a climatically stable area, while the surrounding areas repeatedly saw climate change over million years due to glacial activity. Itombwe Natural Reserve and Kabobo Plateau therefore acted as glacial refugia for these species. This theory has been put forward by Dr. Lovett et al. in a chapter on a book called ‘Phylogeny and Conservation’. They hypothesize as well that such an ecologically stable forest would be characterized by, besides by these relict endemics, the presence of newly evolved species and ecological equilibration. Data on the species of Itombwe and Kabobo indicates that they harbor several recently diverged sister taxa and because they are mainly known from restricted geographic and elevational distributions  support a pattern of ecological equilibration. This leads Greenbaum & Kusamab to say the following: “If Itombwe was indeed a glacial refugium that was ecologically stable during past climatic shifts, there is hope that it could be a reservoir for its astounding biodiversity if future global climate change models are correct in predicting drastic shifts in temperature and rainfall in the 21st century.”

Photograph of the Itombwe Plateau near the village of Tumungu. Copyright Wandege Mastaki Moninga

So what are the prospects for the Itombwe Natural Reserve? It has been established very recently, which is surprising seeing how ecologically valuable the area is. This part of Africa is known for the highest fertility rate in the world and being the most populous area of Central Africa and therefore a high human pressure is being felt in the surroundings, with an inflow from neighboring countries like Burundi and Rwanda. The sever conflict in this region, termed Africa’s world war, has led to an influx of automatic weapons in the region and poaching pressure therefore is very high, causing a catastrophic decline of large mammals like elephants and gorillas. This has affected the ecosystems and these are further transformed by overgrazing by domestic cattle, because people there  make a living primarily by herding. According to a personal communication that is reported in the article, plans exist for building a road thereby making it easier to extract resources from the area and adding human pressure to the already existing ones. This project is funded by the EU and would definitely not help in conserving Itombwe Natural Reserve. A typical example of when nature conservation and human development collide.

The Kabobo Plateau is currently doing better than Itombwe because human pressures are not that high. However, this area is without any legal protection and illegal hunting and mining was observed by the researchers in 2009.

The challenges in conserving biodiversity at both Itombwe and Kabobo are many: not least because  at least three armed militia groups are based within the Itombwe Natural Reserve. Even though the UN are making some progress in disarmament of these groups, they still make scientific research and conservation efforts difficult. When peace would arrive, there are some excellent opportunities for ecotourism in the area, as experience in Rwanda has shown. But at the same time, people living in the area are very logically mainly concerned by their own livelihoods, so hopefully this will not hamper conservation efforts.

In conclusion, the researchers point out that the rediscovery of these species suggests that there is still an impressive level of biodiversity in Itombwe and Kabobo. Therefore, both sites should be protected together to maximize conservation efforts. In conclusion the researchers state: “efforts to bolster INR (Itombwe Natural Reserve, MB) should continue and expand to include Kabobo, predicted detrimental effects of the rehabilitated road through the Itombwe Plateau must be monitored carefully and linked to conservation benefits to local communities, and captive breeding programs must be initiated for the most vulnerable species if conservation efforts cannot improve by the end of this decade. Because additional, new herpetofaunal species await description, it is likely that the Itombwe Plateau’s importance as a center of endemism and conservation concern will increase as biological exploration continues.”

For those interested in another beautiful species discovered by these researchers in Burundi, click the following link 

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