Tag Archives: vegetation

The impenetrable challenge of an overwhelming understorey

The following is a text I wrote for tthe British Ecological Society Bulletin — that was published last month (June 2012). I wrote it to attract interest to a challenge that requires more attention from ecologists and others.  I hope you find it of interest.


Science journals favour tidy theory and rigorous results, but ecological science can also be advanced through highlighting unfamiliar unknowns and quirky questions. For many of us such unknowns are what makes research fun. I want to share a problem (don’t worry, it is about ecology). Maybe you can help.

Our understanding of tropical forest dynamics has advanced considerably over recent decades. We now have vast data-sets tracking hundreds of thousands of tree stems over areas of 50 hectares or more. Numerous processes have been quantified in detail. Remaining unknowns may appear to be minor gaps that will soon be filled. But, for some locations, these impressions are misleading.

For the last few years I have been based in the Bwindi Impenetrable National Park – a World Heritage Site in Southwest Uganda. We can see Rwanda and the Democratic Republic of Congo from here. The site is known for supporting half the World’s remaining mountain gorillas; a major “see them before you die”-tourist-draw that brings in significant revenues to support conservation and the region’s economy. I help run a research station that focuses on the needs of local conservation practitioners (see ITFC.org). We have various day-to-day challenges ourselves – of which I may share more another time – but here I want to focus on our inadequate grasp of forest dynamics.

Living in a salad bowl: fewer than 800 mountain gorillas remain (Photograph Douglas Sheil)

What’s in a name

First, consider the name Bwindi Impenetrable National Park. That “Impenetrable” often leads to raised eyebrows, disbelieving laughter and accusations of ill-judged humour. But it is not a joke: “Impenetrable” is there in the official name. Ask why and you reveal you have not yet been here. Bwindi is rugged, steep and divided by cliffs but the key feature is the thick understorey. It is near impossible to walk through. The main element of this understorey challenge, superseding even the impressively rich flora of noxious nettles, barbed briars and spiny Acanthus, is its remarkable density. Understanding this forest by looking at the trees alone is probably harder than walking through it without tripping over the understorey.

Impenetrable forest – where are the seedlings? (Photograph Douglas Sheil)

Let me sketch out a few local features. The climate here is cool with altitudes up to 2,600m (we huddle at the fire at night). Being one degree south of the equator, seasonal variation is limited but we have two wetter and two drier seasons. Much of the forest canopy is open and there are extensive clearings – this likely reflects slow or stalled recovery from past disturbance (human activities, fires, landslides and elephants are all blamed). Small trees are scarce over large areas – suggesting limited regeneration. Many clearings are filled with persistent bracken fern Pteridium aquilinum (L.) Kuhn.reminiscent of the forests near where I grew up in Ireland. Other understorey species dominate other areas both with and without tree cover. Many of the common understorey species are synchronously monocarpic, living for a decade or more before flowering, seeding and dying en masse. . Examples include the African mountain bamboo (Yushania alpina (K. Schum.) Lin. Poaceae). Like many gregarious bamboo species elsewhere, it forms extensive stands and flowers only every few decades. Other monocarpic understorey plants include various Acanthaceae including several Mimulopsis spp.. One thicket forming species is Mimulopsis arborescens C.B. Clarke. It grows to 4 meters tall and bears multiple soft-woody stems with interlocking stilt-roots that are near impossible to walk through – this plant covers large areas of the forest. Along with another common monocarpic Mimulopsis species (M. solmsii Schweinf.) this is among the mountain gorillas’ most plentiful food plants. Both these Mimulopsis species flowered, seeded and died over the last two years.

ITFC researchers work among the woody remains and seedling carpets of the monocarpic liana Sericostachys scandens (Amaranthaceae): note the bamboo in the background (Photograph Douglas Sheil)

A liana that was abundant in Bwindi just three years ago is also monocarpic. Sericostachys scandens Gilg. & Lopr. (Amaranthaceae) used to cover almost every tree over large areas of forest. Then 3 years ago it flowered and for months its fluffy seeds were everywhere. It is now hard to spot a plant aside from seedlings. Large dead crumbling stems lie in heaps in parts of the forest.

So to recap: large areas of the forest are dominated by a dense understorey. Many of these plants are monocarpic and achieve high densities in cycles that must impact the recruitment opportunities of other plants. Trees are locally patchy and seedlings are often rare. The behaviour of the non-tree vegetation appears key in understanding the dynamics of these forests and, by implication, the animal species such as the mountain gorillas that they sustain.

These issues are not simply a matter of curiosity: major concerns have been raised about the long term management of the forest. These are practical questions. What, for example, should be done about the forest’s vulnerability to fire and to alien species (such as Lantana camara L. now spreading in the northern lower part of the forest)? Specific questions have been raised about maintaining conservation values. Recently the park authorities suggested it may be necessary to artificially maintain gorilla food species by cutting trees. We don’t have anything close to the understanding needed to address these concerns with confidence.

Fun fun fun

How can we get a handle on the key relationships within this complex patchy mountain forest vegetation? How can we, in only a few years of affordable research, grasp how outcomes are determined? If we can’t do that can we at least begin to clarify, gather and store the information that future researchers will need to better address these impenetrable problems? We have some plots with a few thousand tagged trees already. We also acknowledge valuable research elsewhere on seedling-understorey interactions, bracken control, and many other key issues. But we’ll need more, including the sustained funding to achieve it. So can we address this in easy bite-sized pieces? Ideally we would support local students and build capacity as we did it. I am hoping you may have suggestions. If you do please let me know, better still drop by and see just how impenetrable the forest here really is.

Left: Bwindi before, and right:, after last year’s understorey die-back (Photographs by Miriam van Heist)

Hope to hear your thoughts.


Africa’s first GLORIA sites established on the Mountains of the Moon

Dear esteemed reader,

We are glad to be back from establishing the first GLORIA (Global Observation Research Initiative in Alpine Environments) sites in Africa – on the Rwenzori (popularly known as the Mountains of the Moon) and Elgon mountains.  You will have seen some of the earlier pictures from Rwenzori.

Frost, snow, hailstones,freezing temperatures, strong winds, heavy rains and mist – all combined, formed some of the hardships we endured on these intriguing mountains, we could not avoid but wallow in deep bogs, endure bouts of high altitude sickness as well as labour to catch some sleep!!! If it was not for the encouragement of our experienced guides, we may as well have given up before reaching our camps. Nonetheless, the expedition was so exciting that we will live to remember the mind-blowing sight of the spectacular snow-capped peaks, the extensive and gentle calderas and the days we huddled around the charcoal stove just to get some warmth.

GLORIA targets high mountain regions because of their similar climatic conditions across the globe. This makes it possible to compare climate-induced changes worldwide. In addition, mountains host high diversity of plants and animals, many of which can only survive at such high altitudes characterized by low temperatures. Low-temperature limits of plant life on high mountains are considered to be particularly sensitive to climate change. Therefore, potential biodiversity losses caused by climate change may be more pronounced for mountain ecosystems compared to ecosystems of lower altitudes. More still, high mountain environments comprise real wilderness habitats with ecosystems undisturbed by direct anthropogenic influence. Our study will contribute to the global data base which will allow for comparisons of climate change impacts across continents.

This long term monitoring initiative is being implemented in areas where these changes are expected to occur fastest. One hundred twenty eight 1m2 permanent sampling quadrants were established at eight mountain tops (GLORIA Summits) on both sites. Within the quadrants, plant species composition and abundance were assessed. The quadrants were also photographed to provide an overview of plant cover. The summits were geo-referenced using the Global Positioning System (GPS). These high altitude plots were established from 4000 meters ASL. Thirty two data loggers (four at each summit) were installed in the ground to record soil temperature. By comparing plant species composition and soil temperature records, we will get a better understanding of the influence of global warming on plant migrations to higher elevations. All these summits will be re-measured after five years.

The good news is that in Rwenzori some peaks still have glaciers. However, these glaciers are receding fast. One of our experienced guides, John Muhindo told us that there were glaciers even at Elena Hut (about 4500m ASL) in the 1970s. During our fieldwork from the same point, the glaciers appeared to have receded some 300 meters high-up the mountain. We think this could largely be attributed to climate change.

We are proud to pioneer this type of research in Africa. Our team of enthusiastic scientists included ITFC’s Badru Mugerwa, Robert Barigyira and Fredrick Ssali; WCS botanist Ben Kirunda; UWA rangers Abel Basikania, Erick Mulewa, Alfred Masereka, Joseph Wasike, James Matanda, Patrick Muzaale, Alex Salim, Francis Musobo and Mike Mazune. Special thanks go to our trainers Anton Seimon, Stephan Halloy and Mariana Musicante for demonstrating to us the GLORIA methods.

Below are pictures to highlight our GLORIA fieldwork in Rwenzori and Elgon;

Heading for GLORIA field work above 4000 m ASL: the Rwenzori GLORIA team leaves Guy Yeoman hut for the base camp at Kitandara camping ground

Plot established: This GLORIA summit was established near Elena hut at about 4500m ASL in Rwenzori

Another plot established: this GLORIA summit was established at about 4200m ASL in Rwenzori

Men at work: Salim B. Alex (with a pointing stick), Joseph Wasike (middle) and James Matanda identifying plants in the sampling grid of a high altitude GLORIA summit in Elgon

At work: Mulewa Erick (left holding tape on string), Badru Mugerwa (right with black jacket holding clipboard) and Robert Barigyira (in green walking along the tape) record plants in a GLORIA summit of Elgon

One of the GLORIA summits in Elgon with string delimiting the sampling sections: the field team shelters data sheets from a drizzle in misty weather

All smiles… Badru and I after establishing GLORIA plots in Rwenzori


Badru Mugerwa and Fredrick Ssali

Could Carapa seed studies aid forest conservation?

At the end of last month (June 2011), we hosted visiting researchers from the National Museum of Natural History Brunoy, France. Dr. Pierre-Michel FORGET (also past president of Tropical Biological Association in 2007-2009) was accompanied by research partners Dr. Irene Mendoza and Aisha Nyiramana (Ph D student, Muséum National d’Histoire Naturelle and University of Butaré lecturer in Rwanda).

P.M. Forget and Aisha with Carapa grandiflora fruits in Bwindi. ©Irene Mendoza

They were here to evaluate the feasibility of field work on the ecology of Carapa grandiflora (aka Carapa or African crabwood ) in Bwindi Impenetrable National Park. During the one week in Ruhija and Rushaga, they traversed the forest searching for Carapa grandiflora trees and fruits. They succeeded in finding good sites for their study and Aisha Nyiramana will be returning to Bwindi to conduct her doctoral studies during the peak season (of Carapa seed production) in October.

The party gave us presentations about their studies and afterwards a brief interview with Bwindi Researchers’ Ivan Wassaaka. Here are the excerpts from the interview.

Ivan: What brings you all the way to Bwindi?

P.M Forget: I have been studying the use of large-seeded Carapa tree species to protect and save biodiversity of tropical rainforests in Africa and America. So I came to Africa to study Carapa in different countries because there is larger diversity of Carapa on this continent. I have been in Cameroon, Mali, then also Nigeria, Rwanda, Nigeria and in 2006 in Rwanda (with Aisha who is doing her PhD). So I always looked forward to coming to Bwindi to do new studies in a new site.

Our main purpose of coming this time was to evaluate the field conditions and possibility of Aisha doing her PhD work in this park. She is doing a comparative study of Carapa seed distribution in Nyungwe Forest Reserve and Bwindi Impenetrable National Park. The reason she is doing this is because in Bwindi you have elephants which feed on the Carapa and therefore somehow act as agents in dispersing the seeds. However, this is not the case in Nyungwe.

Ivan: How hands-on is your study? What is the significance of this study?

P.M Forget: The relevance is that Carapa grandiflora is a vital Albertine rift endemic species. It is a dominant species in some areas. It forms a major part in the diet of some animals. In some places human beings feed on Carapa. There is serious competition for its fruits and because of the many species that enjoy it, there may be a threat to the plant’s survival. It is therefore important to have the necessary information about the plant, so that the right policy guidelines can be drawn since its existence affects many other organisms. It is almost pointless to conserve the animals (that feed in a tree) without conserving the tree that it feeds on. So in my studies, we are working on ways the conservation of Carapa grandiflora can give way to the conservation of tropical rainforests in general.

Broken Carapa fruits.

Ivan: But Pierre, why Carapa of all plant species?

P.M Forget: When I started my studies ten years ago, I started working on the seed dispersal by different animal species. Carapa was not my main area of study. It was just one of the many species I came across. However, the Carapa (genus) became more interesting to me because I frequently came across it in Africa and America. In my studies, it was very important to have a model species with different methods of seed dispersal. And for Carapa, there are different dispersal mechanisms but all falling in the same model, that’s dispersal by large mammals.

It is also very interesting to me working with a wide range of people from all over the world. We actually have a group of Carapa people working in Brazil, Senegal, Mali, and other tropical countries. We have also developed a website – Carapa.org where we list all the species that have been studies, Carapa uses, ecology, taxonomy, distribution, conservation, physiology, among other things.

Ivan (to Aisha): What brings you all the way to Bwindi?

Aisha: I have been doing an almost similar study in Nyugwe, about the dispersal on Carapa seedlings in the forest. But as it came out, Nyungwe does not have similar large animals like we have in Bwindi. And if you consider the characteristics of Carapa, the fruit is hard and mainly eaten by large mammals like elephants. Unlike Bwindi, there are no elephants in Nyungwe. These elephants (in Bwindi)  feed on the Carapa fruits and could be agents aiding in the seedlings dispersal. So as Forget has already said, my study will be a comparative study of the dispersal of Carapa grandiflora in Bwindi and Nyungwe. The recommendations coming out of my study will then be forwarded to the conservation managers for implementation where necessary.

Aisha Nyiramana in Bwindi. Note the Carapa seedling in the foreground

Aisha Nyiramana standing by a carapa seedling in Bwindi. ©Irene Mendoza

Humans or Elephants – Who is wrecking the Forest?

Open ground due to trampling by elephants

Although human activity is blamed for causing significant loss of forest cover, few studies have documented the role of wild animals in altering, or indeed trashing, their own habitats.  Should we be concerned when animals do this?

While ranging in their forest habitat, elephants leave extensive damage wherever they go. Whether they carelessly or intentionally do this, we all agree that elephants open vegetation, trample, and even sometimes uproot plants thereby causing enormous damage. Even from a distance, you hear them snapping tree branches as they feed or move through the forest.

A patch of the forest opened by the elephant

Most of us know elephants to range in open savannah and can hardly imagine elephants moving around in an ‘impenetrable’ forest. Yet there is an estimated 35-50 elephants ranging in Bwindi Impenetrable National Park. While moving within the forest, you won’t need great skills to tell where elephants have been as there are usually broken tree branches everywhere along their paths.

Fredrick Ssali has recently completed a MSc research project on “the Impact Of Elephants On Trees In Bwindi Impenetrable National Park”. Please see earlier blog introducing this study. His study has clarified this behaviour.

Fred’s study documented tree species, sizes and sites most affected by elephants in Bwindi. He recorded elephant impacts like bark stripping, tree toppling, breaking of branches and trampling over a series of 20 x 4m plots laid out along fresh elephant trails in four sites, varying in vegetation type. In each plot, all damaged and undamaged trees were identified, counted and their stem sizes measured. Of course this was done considering other environmental variables in the study area- the slope, aspect, altitude and tree cover.

ITFC staff assessing impact on trees broken by elephants

The study revealed that elephants are selective in how and where they feed; they target the large and usually less abundant trees for stripping off bark, and usually topple trees or break their branches, when small and abundant. Habitat change mediated by elephants may ead to increased habitat patchiness within the forest. The patches left behind by elephant destruction in Bwindi have usually not been regenerating to primary forest. Rather, frens and other quick growing plants tend to conquere and dominate the patches, thereby suppressing forest recovery. The consequences of this to the general ecology of the forest may be far-reaching but that may call for another study all together.

Some of the patches opened by elephants offer benefits. Other forest animals like the mountain gorillas prefer feeding from the herbaceous vegetation found in these more open areas.

It is a debate. If people were doing this we’d all agree they should be stopped. So, what about the elephants?  Are they wrecking the forest or contributing? As elephant numbers grow we may one day have to consider how many the forest can stand.

Ivan Wassaaka

(with input from Fred and Douglas)

What to do with the old bamboo?

We have just started a new study in Mgahinga Gorilla National Park. This is Uganda’s smallest National Park: an area on the slopes of the Virunga Volcanoes that borders Rwanda and Congo (DRC). It is a fun study.  It is about bamboo.

The African Mountain Bamboo is a key food for several animals. The young shoots provide a valued food to Mountain Gorillas and to the rare African Golden Monkeys (a species found only in the Virungas). According to UNEP “Mountain Gorillas depend on bamboos for up to 90% of their diet in some seasons. The survival in the wild of the Mountain Bongo [a forest antelope] depends on conservation of the bamboo thickets to which it migrates during the dry season”.

Bamboo are also a valued commodity for people in the surrounding communities who use the larger stems for building, old stems for fire-wood and bean stakes, and use young stems for weaving durable baskets. (In Eastern Uganda bamboo shoots are also eaten smoked … but that is not the case around the Virungas).

Botanists have argued a lot about what to call bamboos. The problem is that botanists like to have flowers to base plant names on … and bamboo doesn’t flower often which makes it hard for them to classify. The African Mountain Bamboo has at least three names to confuse everyone: Arundinaria alpina or Sinarundinaria alpina or Yushania alpina. It is all one species.

Pontious – Sr Warden in Charge of Mgahinga Gorilla National Park explains the challenge of the bamboo.

The Virunga mountains are a scenic place to work

The Uganda Wildlife Authority (UWA) has been concerned that the Mgahinga Mountain Gorillas are spending less time in Uganda  than in the neighbouring countries. That means that tourists who visit are sometimes disappointed. One suggested reason why the gorillas do not stay longer is that the bamboo was old and dry and not producing the young shoots that would (twice a year) attract the animals to feed. It is also a concern regarding the Golden Monkeys.

Much of the park’s income from tourism depends on the gorillas and the monkeys. At the same time, MGNP management is under pressure from local communities who are eager to access bamboo. UWA asked us at ITFC to help them with a study: if they allowed local people to cut the dry stems would it encourage the bamboo to produce more young shoots?

UWA had already gone ahead selecting an area where local people were allowed to cut and collect dry stems for building and fuel.  That was completed a year ago.

So we though we could try and help. We visited Mgahinga in mid September to see the site with UWA staff. We then designed our study. Then in the early days of October,  two ITFC volunteers together with MGNP rangers and ourselves spent a few days in training and started the actual data collection. We had two small teams and spent a lot of time counting, measuring and assessing bamboo stems. Our teams included UWA Head Ranger Research and Monitoring: Barebwa Ismael, three UWA Rangers: Uwihoreye Allen, Adrama Francis and Halera George and two ITFC volunteers: Ssali Frederick and Mukasa Joseph. The photographs should give you some feel for these forests.  It is high up (about 2,500 meters plus) and cool.

We never saw any wild buffalo, though their tracks were everywhere (the rangers need to carry a rifle just in case — the buffalo are often agressive). We did not see the Golden Monkeys but we heard them close on a few occasions. There was an odd popping sound that carried through the forest as the monkeys snapped off the young nutritious bamboo shoots.

Training at Mgahinga — training is an important part of the research process.

Training at Mgahinga — counting bamboo is not so simple!

Training at Mgahinga — counting bamboo needs care and attention.

Joseph and George reading the calipers – Mgahinga.

Bamboo forest – Mgahinga

Bamboo forest – Mgahinga

In an ideal world UWA could allow local people controlled access to bamboo without it having any negative impacts … it may even increase the food available for Mountain Gorillas and Golden Monkeys.  Perhaps that is true, we don’t know yet. We’ll wait and see the data.  That’s applied research.

Best wishes


Bwindi elephant research: the experience of an ITFC sponsored student

Dear esteemed readers,

Allow me to register my sincere and hearty gratitude to ITFC for supporting me financially and academically in my study of elephant impacts on trees of Bwindi Impenetrable National Park. I am indeed grateful.

I first came to ITFC in June 2009 as a prospective student following my application for scholarship and was given a warm welcome. The main aim of this visit was to discuss my intended project with the ITFC Directors and staff and also to gain first hand impression of the impenetrable forest since I had never been to Bwindi. I was pleasantly surprised to find good facilities at ITFC, notably, a rich library, spacious dormitory, comfortable vehicles, offices powered by solar and with fast internet, to mention but a few. In addition, I found that ITFC had welcoming and altruistic staff who guided me as I easily familiarised myself with the place and got ideas to improve my research proposal. After spending more than a week in Bwindi, I left ITFC determined to do my best to produce an improved proposal that would merit selection for ITFC scholarship. Thank goodness, my efforts were rewarded with this scholarship and I breathed a sigh of relief since I had found an ideal place to conduct research.

After being selected, I came back to ITFC eager to try out my research methods and find elephant ranging areas as well as clear elephant impacts along fresh trails. However, I feared that the task ahead of me was not going to be easy since Bwindi elephants had been little studied, so there was little information to guide me. I was helped by the people neighbouring the park, UWA rangers and the ITFC field assistants who volunteered information about elephants’ whereabouts and guided me in my quest. My fears were further heightened by the thought of going up and down the rugged terrain of Bwindi. In addition, I could not imagine myself deep in the jungle searching for these giant and potentially dangerous creatures. In a nutshell, my mind was kept busy with the challenges of study.

As if to confirm my earlier fears, the pilot study exposed me to the anticipated challenges posed by the rugged terrain of Bwindi. I found myself constantly stumbling, puffing, panting, gasping and sweating profusely during the first days of field excursion. One day while walking slowly behind my field guide, I paused and pondered what it would take to get the better of the hills, valleys and thick vegetation of Bwindi. I then gazed at the ITFC field guide ahead of me and couldn’t help but envy his ability to go uphill and downhill seemingly effortlessly. This prompted me to contemplate taking fitness lessons so as to be equal to the task since the going was getting tough day by day. Fortunately, I soon grew accustomed to the demanding field excursions and was able to complete the pilot study and field work successfully.

During field work, ITFC assigned me a hard working team of experienced field assistants that included Christopher Byaruhanga, Caleb Ngambeneza, Savio Ngabirano, and Beda Turyananuka. They knew the forest so well that many times the GPS was rendered unnecessary in locating the study sites. They also helped me in identification of trees damaged by elephants and the trees that were not affected at all. In addition, these field assistants were always good company. I recall vividly the nights we were in the forest camping and shared stories around the fire place as we warmed ourselves in an attempt to relax after a hard day’s work. This made the entire field work exciting and successful. I thank Christopher, Caleb, Savio and Beda for helping me during field work. They are my Bwindi grand masters!

The photos below highlight what transpired during field work;


Caleb (holding machete), Beda (blue sweater) and a ranger marvel at an open ground left by elephants digging up P. aquilinum rhizomes for feeding


Christopher prepares to measure the size of a tree toppled by elephants along the banks of river Nshongi


Caleb spreads out fresh elephant dung searching for seeds which passed through the elephant gut


Left to right: Christopher, Gerevasio (porter), Savio and Sepe (camp keeper) take a break on our way back from camping near Mubwindi swamp, an area frequented by Bwindi elephants

Results of this study showed that Bwindi elephants affected some trees more than others. This varied with species, size and location. In addition, elephant impacts varied with altitude and distance to forest edge. Given the restricted range that elephants use in Bwindi, it is likely that habitat change mediated by elephants may not homogenize the park’s vegetation but rather lead to increased habitat patchiness. There is need to mitigate wanton anthropogenic activities, such as wild fires, that would exacerbate the elephant problem in BINP.

Look out for my thesis abstract on www.itfc.org!

Fredrick Ssali

Searching for gorilla food in Bwindi’s Northern Sector

The northern sector of Bwindi is very steep and rugged. It is lower than the rest of the park and hosts different plant species. The Northern Sector is attached to the main forest by a narrow corridor called “the neck”.  Mountain gorillas have not been seen in this most Northerly part of the forest for as long as people remember.  Though that has recently changed.

Since about three years ago, one of the gorilla groups already habituated for tourists has from time-to-time entered through the neck into one corner of this Northern Sector … They tend not to stay long before returning to the main forest block.

Why do gorillas avoid this area?   Perhaps, some people suggest, it is a lack of food plants like Myrianthus, Mimulopsis, and Triumfetta.


Rugged terrain, forested hills and valleys of the Northern Sector

I was involved in a study to examine this, comparing the distribution, availability and abundance of gorilla food plants in the Northern Sector with that in the south, where Mountain gorillas do occur. The study was organized by the MPI (Max Planck Institute) based in Germany that has a long term research collaboration in Bwindi on gorilla ecology and sociology. We assessed the vegetation, identified and recorded the Mountain gorilla food species (herbs, climbers, shrubs, trees), and counted the number of plants and even their leaves .

We camped for two weeks at a time inside the forest, walking long distances looking for our next sampling plots. Heavy rain would often shower on us and stop us from working. Sometimes we were very wet and cold. In the evening we need to hang all the wet clothes and hope that they can dry overnight.

This northern area is very rugged and steep slopes, many areas are difficult to cross. It was tough but also fun.  Often we needed to make big detours to reach our sample locations. We often fell, and often found ourseleves sweating and covered in mud after crossing boggy areas. But we stay cheerful and often laugh together.


Crossing river Ishasha looking for sample plots

Many trees that occur in this area, particularly along the river Ishasha, are not found elsewhere in this forest or indeed in other forests in Uganda. An example is a tree called Allanblackia which has huge fruits (if they fell on your head they might kill you). Special tree species are found in rocky areas where it is amazing that tree roots can penetrate, some along the river and others in the flat plains. This was interesting to me as I saw things I have not seen elsewhere. Sometimes you feel as though no one else has ever been there before as the place is so wild and special.


Doesn’t this place look special ?

Our survey was done to find the availability of gorilla foods so as to compare  with other areas where gorillas normally range. In my personal observations, the gorilla food presence and distribution was indeed lower that in other areas where gorillas occur. The vegetation is also patchy and in some areas fire has damaged the forest and is full of dense bracken fern, grass or other young plants. Basing myself on the experience, trainings and the time I have taken serving both in UWA and ITFC, I have enjoyed field camping and the type of the work involved and I love wildlife conservation.

Let me know what you think.


Tracking wild bananas … and a story in your fruit bowl

A lighter one this time. Today we went hunting for African wild bananas. Really.

They are not common but I had spotted some distinctive plants in a nearby valley and wanted a closer look. As with so many Bwindi stories this one started with a steep descent. The easiest path followed the park boundary. The in-park side is mainly regrowth after an area of plantations was cleared some years ago. The area outside the park has been planted with pine seedlings and, lower down, a small area of tea.

We had heard and occasionally seen the crowned cranes that visit the small swamp at the valley bottom. These elegant birds were hooting today. We saw them as we reached the swamp, and they saw us. They watched us with their characteristic poise and confidence.

Despite months without significant rain, the mud in the swamp remains soft. We tried to cross. After my first trial steps I struggled to withdraw as I gently began to sink. The dark ooze that rapidly filled my foot prints released a noxious egg smell (sulphide). Luckily I still had my boots.

A Crowned crane near Ruhija. We saw a pair of birds. They hooted loudly at intervals through the morning.

We edged around the swamp and then moved into the forest following a trail that soon petered out in a cluster of bee hives. We pushed on climbing now. Much of the forest here is thick scrubby vegetation. We had underestimated how thick the vegetation was. We had to struggle to find a good vantage point to spot our quarry. Our clothes, and even our hair, were soon covered in the spiny and hooked fruits of plants that viewed us as a passing opportunity to disperse their seeds.

Finally, we had a good view. The large leaves of the banana plants are unusual in these forests and stand out clearly even at a distance. I counted more than 90 plants growing near the valley bottom.

Can you see the wild bananas (Ensete ventricosum)?

See the large broad leaves? That’s them: wild bananas!

So I have bananas on my brain day. I was thinking that for some of you bananas are a very familiar link that leads to the rain forests. Let me tell you some more about that. Bananas are amazing.

What surprises many who first encounter wild bananas (whether in Africa or elsewhere) is that the fruit contain large numbers of hard dark typically pea-sized seeds. Generally speaking, all wild bananas need seeds to disperse to clearings in the forest and thus persist from generation to generation in a changing environment of trees and gaps.  Occasional  seedless mutants must occur from time-to-time but such plants will not survive long unaided.

Wild banana showing dark hard seeds.

African bananas occur in mountain forests. They have been domesticated in the highlands of southern Ethiopia where they are a major component of the diet. The wild plants now have a relatively restricted distribution making them of some conservation interest. As they feed many people in often drought ravaged parts of Ethiopia they may prove to be a crop with wider value in the future (they taste good too).

Unlike the exposed stacked “hands” of fruit seen in the Asian bananas (as in your local shops), the African plant sheaths its flowers and fruits in a succession of lampshade like structures that makes a large heavy flower and fruit filled tassel. Take a look at the picture.

A view into the flowering tassel (inflorescence) of an African banana (I’m cheating here and using a picture I took some years ago of a domestic plant in Ethiopia).

The African plant is an Ensete to distinguish it from the Musa to which other edible bananas belong (other Ensete species also occur in Asia [and Madagascar]). There are no true wild banana species in the Americas (where their closest relatives include the broad leaved Heliconias commonly seen as ornamentals). Most wild banana species (mostly Musa and a few Ensete) today occur in South East Asia, especially in the many islands of Indonesia, New Guinea, and the Philippines and also in Malaysia. These Asian wild plants are dependent on animals such as bats and tree-shrews for pollination.  I am unsure what the African banana requires, though I would suspect bats or sunbirds (maybe someone can tell me please?).

The bananas we eat lack seeds. These eating bananas were likely domesticated in New Guinea, where bananas have been cultivated for at least 7000 years. These varieties have been utterly dependent on humans for their vegetative propagation and survival ever since they lost the ability to produce seeds. They are clones, though mutations for sweeter forms etc. must have arisen and been selected form time-to-time. These seedless forms somehow made it to Africa. Archaeological evidence suggests the cultivation of (Asian or New Guinea) bananas from a few centuries BC in Cameroon and just possibly (the evidence is suggestive but not conclusive) from five thousand years ago in Uganda.

Claims of cultivated bananas in South America before Columbus are debated. Such vast ocean crossings are not wholly implausible. We know that the Polynesians carried bananas to some Pacific islands. Banana plant sprouts can survive in storage for several months, enough time to cross an ocean. We know too that sweet potatoes, originally from the Caribbean, travelled the other way across the Pacific and were well established in the New Guinea highlands long before the arrival of the astonished Europeans.

Today we found our wild banana plants in the forest. Those in your fruit bowl are direct vegetative descendants of plants once also found in the rain forest and transferred from human hands to human hands since long before the dawn of history. What rain forest riches shall we leave for future generations?

Interesting or boring? Perhaps we should we avoid plants in a wildlife blog …?  Let me know.

Best wishes


p.s. I should be clear that I cannot be certain that the plants we saw are really wild without checking each for seed in their fruit.  I hope to make a check soon.  It will take some cutting to get there.  Will let you know …

What is the point? Placing plots in an impenetrable forest

Clutching our equipment and a few scribbled notes, we descended into the Bwindi Impenetrable Forest. We were not looking for Mountain gorillas. We were coming because we plan to watch the trees. In fact, working with instructions from Conservation International in the USA, we were going to check out proposed plot ” VGBIF4P”. Not as glamorous as gorilla tracking but important nonetheless.

Bwindi Forest is much more open than most tropical forests

We intend to add Bwindi to a select number of tropical forests around the world which will be closely monitored. The hope is that these observations will help provide a better idea of the World’s health. The site we were checking is one out of a longer list of places where we plan to set up a big square 100 meter by 100 meter plot (one hectare) in which we shall record and measure trees every year.

Initially we followed the steep trail down from just below the station. Elephants had just been here! There were broad elephant footprints in the soft mud, fresh mounds of dung, and several smaller snapped trees. I am surprised we hadn’t heard that as we live so close by. We followed the signs as we descended. In this forest even elephants prefer paths.

After about an hour we had to leave the path and cut across country moving through the dense undergrowth relying on compasses and global positioning units (these use satellites to provide a precise location; we are lucky to have had a good one donated recently by a visiting student from Edinburgh University). Moving through the forest is much slower and harder than following the trail – our lead field assistant had to cut and hack through the thick vegetation. Bwindi is a Mountain gorilla salad bar but the salad is tough.

A Bwindi bog: Mubitukura Swamp. Our plot should be near here.

The proposed plot VGBIF4P (E 0807197 and N 9883272) occurs inside Mubitukura swamp . Global positioning units are a vital part of our equipment.

If you know tropical rain forests, this thick herbaceous vegetation is not what you expect. In most tropical forests the vegetation near ground level is heavily shaded, plants are widely scattered and easy to walk between. But in this part of Bwindi the trees are often patchy and the canopy is open casting little shade. As in a normal rain forest many of the trees hold clumps of orchids and other plants high in their branches (plants growing on plants = epiphytes). Many trees are swathed in vines and other climbers. The difference is in the open nature of the forest which means that plenty of sunlight gets near to the ground. Plants grow thickly and the undergrowth is dense with a tangle of vegetation that catches around ankles as you try to take extra high steps to get over them. The main plants are called Mimulopsis – if you were a Mountain gorilla, these would be part of your daily diet.

I tried with mixed success to avoid the more localised long-spined nettles. These had little trouble penetrating the thin fabric of my trousers. The flora here is rich in stinging and spiny plants.

Ouch! Bwindi’s nettles. The long stinging hairs have little trouble penetrating clothes.

Forests are constantly changing. Trees germinate from seeds, grow and after years or centuries, they die. Because most of these changes are so slow they are hard to observe. So we need careful research.

Why do we need such research? Let me provide a couple of arguments (let me know if you get bored!).

If forests are always changing, the quality and value of the habitat is also changing. Conservation values are not guaranteed. For example, will the forest continue to provide the food that Bwindi’s Mountain gorillas depend upon? If we don’t make good observations it is hard to know (and there are reasons to worry – I’ll leave that discussion for another time).

Let’s zoom out and look at the bigger picture. A recent United Nations global summary of changes in our planet’s ecosystems summarised 30,000 sets of scientific observations. Sounds impressive right? But for those of us concerned about the wealth of species that live in the tropics there is an important clarification. Only 15 of these studies, (0.05% of the whole) are from the tropics. Scarcity of reliable data is one reason there are still so many arguments about climate change etc. and its implications. It bears repeating too that we know least about the places which have most of the species – the tropical forests!

A recent study I contributed to combined many small localised periods of observations of forest changes across tropical Africa and reached a surprising conclusion: the forests were increasing in the bulk-amount of trees they contained. While we argue about the causes of these trends they seem real and are big enough to influence the world’s atmosphere (reducing carbon dioxide – the main gas responsible for concerns about global warming). Similar forest changes have been observed in the Amazon rain forests and elsewhere suggesting a truly global phenomenon. This is important as it helps explain where some of the carbon dioxide that humans have been releasing into the atmosphere has been going.

Anyway, back to our plot. We eventually found our selected point after about 3 hours. Luckily we were all in rubber boots because this was a bog … the plot would have to be moved. We followed our guidelines carefully locating a series of sites in turn until we had a location which satisfied all the criteria. We took time setting up the square and marking the corners. The rain came pouring down. The bog’s frogs started singing. We were quickly soaked.

Badru and Bennon laying out the plot edge

Cutting the thick undergrowth to make a straight plot edge

When the plot survey was finished we returned to the station as quickly as we could without slipping. My rubber boots making dramatic slurping noises on each step as my wet socks pumped the air in and out. Finally we were back: a hot drink, a wash and a chance to dry my by now horribly wrinkly water-logged feet. A successful day. One site checked … many more to go. Then there’ll be years of measurements to do (as long as Conservation International agrees to support it). Who knows what we’ll discover?

Tree watching is not as glamorous as tracking gorillas, but I think it’s important. Let me know what you think.