Sky islands: exploring East Africa's last frontier

The montane rainforests of East Africa are little-known to the global public.
The Amazon and Congo loom much larger in our minds, while the savannas of East Africa remain the iconic ecosystems for the region.
However these ancient, biodiverse forests – sitting on the tops of mountains rising from the African savanna – are home to some remarkable species, many found only in a single forest.
A team of international scientists – Michele Menegon, Fabio Pupin, and Simon Loader – have made it their mission to document the little-known reptiles and amphibians in these so-called sky islands, many of which are highly imperiled.

Forest canopy on the sky island of Nyungwe, Rwanda. Photo by: Michele Menegon.

The montane rainforests of East Africa are little-known to the global public. The Amazon and Congo loom much larger in our minds, while the savannas of East Africa remain the iconic ecosystems for the region. However these ancient, biodiverse forests—sitting on the tops of mountains rising from the African savanna—are home to some remarkable species, many found only in a single forest. A team of international scientists—Michele Menegon, Fabio Pupin, and Simon Loader—have made it their mission to document the little-known reptiles and amphibians in these so-called sky islands, many of which are highly imperiled.

During the past 15 years, the scientists have already conducted several biological surveys in a number of high-altitude forests in East and Central Africa, including Ethiopia, Tanzania, Rwanda, Uganda, and Democratic Republic of the Congo. Their expeditions have resulted in a number of new specie, with many more awaiting description. But that work hasn’t kept them at their desks. The team now plans to visit the almost wholly-unknown sky islands of Mozambique, including three mountain forests: Mecula, Injese, and Mabu. However, the trip that has recently been delayed due to political instability.

Unfortunately, time is running out for many of the region’s sky islands as growing human populations and rising economies have led to increasing deforestation on some mountaintops. The most imperiled, according to the team, are the Bale forests in Ethiopia. But not only are the scientists uncovering new species—and further illuminating evolutionary connections in the region—they are also using their discoveries to convince governments to protect these irreplaceable ecosystems.

In a December interview with mongabay.com, the team with the Science Museum of Trento and University of Basel talk about why Africa’s sky islands are so important, past discoveries on these mountaintop havens, and their upcoming expedition to Mozambique.

INTERVIEW WITH MICHELE MENEGON, FABIO PUPIN, SIMON LOADER

Bush viper chasing the photographer. Photo by: Michele Menegon.

Mongabay: What are your backgrounds?

Michele Menegon, Fabio Pupin and Simon Loader: We are scientists. In particular, we’ve been working on amphibians and reptiles of the Eastern Afromontane hotspot for 15 years (Fabio joined the team 5 years ago) for the Science Museum of Trento and University of Basel, collaborating with most of the international agencies operating in the area.

AGE OF EXPLORATION?

Mongabay: What compels you to explore these little-known ecosystems?

Simon Loader (left) and Michele Menegon (right) in the Uluguru Mountains in Tanzania. Photo by: Vaclav Gvozdik.

Michele Menegon, Fabio Pupin and Simon Loader: We are naturally curious and the main fulfillment for us is to know a bit more about our planet. Of course, this means focusing our efforts on particular fields of study and ours is the understanding of the amphibians and reptiles communities of the montane forests of Eastern Africa. It’s a microcosm far from being fully understood, and we are just starting to scratch the surface.

Mongabay: Why is it so important to support biological expeditions like these?

Michele Menegon, Fabio Pupin and Simon Loader: There are a number of good reasons, but firstly such expeditions increase our knowledge of an area, which is both personally satisfying but also vital for its future preservation. Such knowledge is important in our ability to distinguish the important areas that we should try, at all costs, to preserve. Personally we also like to explore these places for our own curiosity and thirst of knowledge—this is a great motivation to keep returning. Doesn’t everyone want to know the place where we all live?

Mongabay: Are we still in an age of discovery? Or an age of global ecological decline?

Michele Menegon, Fabio Pupin and Simon Loader: Actually, the age of discovery will never end, at least until the age of global decline reaches its end goal. Whether that’s soon or not is difficult to tell.

EAST AFRICA’S SECRET SKY ISLANDS

Trees in the mist in Nyungwe Forest in Uganda. Photo by: Michele Menegon.

Mongabay: East Africa’s montane rainforests are lesser known globally than its surrounding savannahs. So what makes them vitally important?

Michele Menegon, Fabio Pupin and Simon Loader: Montane rainforests are beautiful and intriguing places to work for us, however for people living in, and around it (even in large cities hundreds of kilometers away), they are highly dependent upon them. From water and food resources, to the stable environment and climate they provide—rainforests are important habitats. Compared to savanna habitats, though savannas provide important tourist incomes, rainforests have significantly greater importance to human populations because of the ecosystem resources they provide.

Mongabay: Why does the age of these ecosystems, around 30 million years, matter so much?

Michele Menegon, Fabio Pupin and Simon Loader: The age of an ecosystem doesn’t matter per se, but the diversity and abundance of the natural resources does, and the age gives a good estimation of the worth of such resources. Often, age correlates with the biological richness of an habitat, with greater age we see more species and the evolutionary distinctiveness of them. If given the choice to preserve 10 different species of amphibians, or 10 different types of vertebrates we would choose the later in order to preserve as much biological diversity as possible. Similarly, we would choose to preserve areas that harbor large amounts of biological diversity, not only in terms of numbers of species but evolutionary history.

Mongabay: You’ve explored a number of Africa’s ‘sky islands’ already. Will you tell us what you have discovered?

The range-restricted Rhampholeon viridis from Tanzania’s Pare Mountains. This species remains unassessed by the IUCN Red List. Less than half of the world’s reptiles have been assessed by the IUCN. Photo by: Michele Menegon.

Michele Menegon, Fabio Pupin and Simon Loader: We have discovered several species new to science and have numerous species that await description. Of greater significance and interest than even discovering new species, we have estimated genetic relationships among these many species (described or not) to better understand the evolutionary history of these groups. From this work we are starting to understand the tempo and mode of evolution in the Sky Islands of East Africa.

For example, our work has revealed that many species show relatively long evolutionary histories, suggesting that the habitats they occur in (sky island forests) are equally as long lasting. Furthermore, although most sky islands show long evolutionary histories some show large radiations of species whereas others are not so numerous in terms of species. The reasons for these differences are interesting to us and suggest something different about the biogeographical histories of these areas.

Mongabay: What new species particularly standout from all your expeditions?

Callulina meterora, a recently described frog from the Nguru Mountains, Tanzania. Photo by: Michele Menegon.

Michele Menegon, Fabio Pupin and Simon Loader: There are many new species that are spectacular, but among the most impressive species we have described is the brightly coloured glandular warty frog (Callulina meteora) from the Nguru Mountains in Tanzania—meteora refers to “it coming from the sky” as something quite remarkable and mythical. It is quite a spectacular looking frog and is found in a small area of beautiful pristine montane forest. In part, the finding of this frog has helped to highlight the biological importance of this area—which has recently been made into a nature reserve: Mkingu Nature Reserve. The Matilda horned viper is also remarkably beautiful (yes, vipers are beautiful…). It was named after a 7-year-old promising herpetologist who spends part of her childhood in the forests of Mount Rungwe, in Southern Tanzania.

Mongabay: What are imperiling these ‘sky islands’?

Michele Menegon, Fabio Pupin and Simon Loader: Habitat destruction continues to threaten all sky islands, though some areas are at a significantly greater risk than others. We suspect in some cases that some species are perilously close to extinction because of such habitat destruction. For example, we studied the herpetofauna of the Ethiopian Bale Mountains and found worryingly few individuals, and in particular certain species were extremely rare or absent. The large degree of habitat destruction in this region appears to be the main factor that could account for such declines. Declines in frogs also likely means declines in other species.

Mongabay: How does expeditions like yours result in on-the-ground conservation?

The rare and recently described Matilda’s horned viper (Atheris matildae). Photo by: Michele Menegon.

Michele Menegon, Fabio Pupin and Simon Loader: Results from our surveys and the subsequent scientific work have shown areas to be of biological importance—either in line with previous biological work or providing a new perspective. This can be manifested in the description of new species or the finding of rare, evolutionarily-distinct species. The consequence of these field surveys is to increase knowledge and understanding, which are all considered in prioritizing conservation effort. In particular, we think that our work aims to highlight and draw attention to certain areas—and convince administrators that an area is of biological importance and therefore of worth to humans. The worth of biodiversity to humans is increasingly understood in terms of the ecosystem services that the biologically diverse forests of the sky islands provide—such as water catchment and sustainable forest products. In addition to providing important data, we are always working with locally-based scientists, and by working together we can share each of our expertise. In our planned expedition to Mozambique two students will be with us, sharing knowledge, along with other local people. This transfer of knowledge is vitally important for all, and our aim is to improve the capacity for Mozambicans to conduct such work independently or collaboratively in the future.

TO MOZAMBIQUE

Mongabay: Why survey the ‘sky islands’ of Mozambique next?

Michele Menegon, Fabio Pupin and Simon Loader: We are attempting to fill in a gap of knowledge of the Eastern Afronmontane region. In comparison to both the north and south, our biological understanding is very poor indeed—we need to remedy this by conducting biological surveys. Furthermore, the Mozambican mountains, which are geographically in between areas that are well understood (both north and south) prevents us from a comprehensive understanding of the Eastern Afronmontane region.

Mongabay: Will you tell us about the particular rainforests you will be exploring in Mozambique?

A galago from the Udzungwa Mountains in Tanzania. Photo by: Michele Menegon.

Michele Menegon, Fabio Pupin and Simon Loader: We are going to focus on forest capped inselbergs in the Niassa and Nampula provinces. These forests are in small pockets, but the little data we have on their inhabitants suggest stable and ancient environments, this means long evolutionary history in isolation. And we love these premises.

Mongabay: What do you expect to find?

Michele Menegon, Fabio Pupin and Simon Loader: Part of the fun of what we do is that we are not entirely sure what we will find, but we do expect to find species that either closely resemble or are somehow different from other Eastern Afromontane regions. The extent to which they are similar will be the key to understanding the evolutionary history of this region.

Mongabay: Your focus will be on amphibians, reptile, and invertebrates. Have these sky islands already been surveyed for mammals and birds?

Harenna Forest in Ethiopia. Photo by: Michele Menegon.

Michele Menegon, Fabio Pupin and Simon Loader: Our focus will be entirely on amphibians and reptiles—already a big job! Mozambique is generally poorly understood and this is true for most animal and plant groups.

Mongabay: Are any of these three rainforests currently under threat?

Michele Menegon, Fabio Pupin and Simon Loader: Montane forests in Mozambique are small patches on isolated inselbergs, many of them are still in good condition, but often economic growth means expanding exploitation of natural resources and Mozambique is one of the fastest growing countries in Africa. It’s of vital importance to document the biological value of this forests in order to take them into the account during the process of land planning

Mongabay: A film crew is coming along. Where will people be able to view the film once it’s released?

Handling a Gaboon viper. Photo by: Renzo Vicentini.

Michele Menegon, Fabio Pupin and Simon Loader: We have a dedicated webpage where people can find news and updated on the expedition and once the post-production will be completed we’ll announce the when and where of the film. The film crew is planning to reach some festivals etc.

Mongabay: Your team has run into some issues ahead of the biodiversity survey in Mozambique. Will you tell us about what has occurred?

Michele Menegon, Fabio Pupin and Simon Loader: After twenty years of peace, outbreaks of conflict between government forces and the main opposition party have been reported during the local elections of November 20th. At first, clashes occurred in the south of the country, far from the planned study area. However, turmoil has subsequently spread to other central and northern provinces of the country. For some time the situation has remained unstable and difficult to interpret and the first step was to postpone the departure a few weeks.

Apparently, the elections of the 20th of November were held in a relatively quiet and uneventful climate, but given the situation and the difficulties in receiving precise and reliable news from Mozambique, especially regarding the specific areas where we were planning to conduct the surveys, two members of the team—already in Tanzania for finalizing the preparations—decided to travel to Pemba in Mozambique, to meet up with the Mozambican member of the Sky Islands team and check on the actual safety conditions. Unfortunately, and at least at this stage, the picture was found incompatible with the guaranteed minimum safety condition for the members of the expedition and so it was decided to postpone to the next rainy season.