Extract from 'Account of meeting - Ness Botanic Gardens, 1996' (BBS AGM meeting)

R.D. Porley (English Nature): 'The Darwin Initiative bryological expedition to Uganda'.

The Tropical Bryology Group last had a bryological expedition to Africa in 1991, when seven members went to Mulanje Mountain, Malawi. That expedition was largely self-financed. Progress has been steady with naming the collections and publishing the results. However, to maintain and develop the groups' expertise in tropical bryology, particularly in the field, it was decided to return to Africa. It was agreed that this time we would need to seek funding for the expedition, and we submitted a proposal to the Darwin Initiative in late 1994. This is a fund established by the UK government following the Earth Summit in Rio de Janeiro in 1992. Its purpose is to support the development of an integrated strategy for the deployment of UK scientific, industrial and managerial expertise to assist developing countries implement the Convention on Biological Diversity.

We were delighted to learn that the proposal had been successful and that we had secured funding to enable a three year project to go ahead. The project was to study and document the bryoflora of montane rain forests in Uganda. The present political stability in Uganda, the dearth of published bryological data for the country, the pressing priority to document the biodiversity in one of the richest parts of Africa, and to contribute to the effective conservation of the rain forests convinced us that Uganda was the country to go to. Furthermore, Uganda represents something of a gap in our knowledge of the bryoflora of East Africa, with Tanzania, Kenya, Burundi, Rwanda and eastern Zaire being relatively better known.

There are five key objectives of the project:

• to make as complete an inventory as possible of the bryophytes of Bwindi Impenetrable National Park, Rwenzori National Park and other montane forests in western Uganda.
• to compare the bryophyte floras of these areas both with each other and with other East African forests.
• to identify centres of bryological diversity as a contribution to their effective conservation.
• to communicate the bryological importance of the study areas to specialists and administrative authorities.
• to facilitate the study of bryophytes in Uganda by providing bryological literature and training for local botanists, and donating a set of named vouchers to the herbarium of Makerere University.

Six UK members of the Tropical Bryology Group, Jeff Bates, Nick Hodgetts, Howard Matcham, Ron Porley, Robin Stevenson and Martin Wigginton left England on 19 January, 1996. We were joined in Kampala by Stephen Byarujali and Berna Nakityo of Makerere University.

Uganda is about the same size as the UK although 25% of the country is water (Lake Victoria, Albert, Edward, George, Kyoga and The Nile). It is situated on the equator on the Central African Plateau with most of the land over 1000 m above sea level. The Rwenzori, Ptolemy's fabled Mountains of the Moon, forms the western border with Zaire, and Mt. Elgon rises above the plains over to the east on the Kenyan border.

Bwindi Impenetrable National Park, the main study site in year one, is located in the south west corner of Uganda at the end of the western arm of the Great Rift Valley. It covers some 321 km and varies in altitude from 1160 m to 2600 m. It is of one of the few forests in East Africa to show an intact altitudinal zonation from lowland forest type, through sub-montane to montane. The known flora and fauna of Bwindi is impressive: there are over 1000 vascular plants, possibly a greater number of trees than in any other East African forest, there are several endemic trees and many central African trees reach their eastern limits here. It is the best forest for primates in East Africa, supporting about half the global population of mountain gorilla. In addition there are chimpanzees, black and white colobus and several Cercopithecus species, 58% of African montane birds, also occur in Bwindi, including the spectacular Rwenzori turaco. Bwindi is an important Nile catchment area and is vital for watershed protection (facilitated by the large bryophyte biomass acting as a slow release sponge).

The drive from Kampala to Bwindi, which took us across the equator, was about 400 km. It seemed to be twice as far though because of the rather ancient Landrover (probably from the old Colonial days) which we had the use of. Howard was voted to be our main driver and it was no easy task. However, despite the bonnet having to be raised far too frequently, it did eventually get us there (and back). Daily sorties on foot were made into Bwindi forest from Ruhiija, our base for the first half of the trip, and then from our base at Buhoma, which took us further north.

Bryophytes were collected from as wide a range of habitats as possible; particular attention was paid to twigs and branches laying on the forest floor as this was the only way to sample the canopy. Typical plants found in this situation were Mastigophora diclados, Chandonanthus hirtellus and Macromitrium spp. The forest floor, on bare exposed earth banks, could also be rewarding, with Telaranea nematodes and two ecostate Fissidens species, F. bryum and F. usambaricus, all previously unreported for Uganda. However, trees proved to be amongst the most productive of the habitats for bryophytes, supporting diverse range of epiphytes and epiphylls.Plagiochila squamulosa was particularly prominent, together withPilotrichum sp., Calyptothecium hoehnelii, Porothamnium spp., Syrrhopodon gaudichaudii and, more rarely, Prionodon sp. More familiar plants were also present, such as Pterogonium gracile and Leptodon smithii. Buhoma was noticeably more humid than Ruhiija and correspondingly richer in bryophytes. Epiphylls were encountered in some quantity, including the distinctive Radula flaccida and Caudalejeunea sp. Other notable plants from this area, and not so far recorded for Uganda, include Distichophyllum rigidicaule, Homaliodendron piniforme, Syrrhopodon gardneri and Frullania diptera.

In addition to the general collecting, Jeff Bates was keen to undertake an ecological study or two. The main study involved investigating bryophyte diversity and species ranges in relation to altitude. Five plots, 25 x 25 m, were delimited at points along an altitudinal gradient and all bryophyte species recorded noting whether on trees , rotting wood, rock, on leaves and so on. Observations on stand structure, vascular flora and topography were also made. Alongside this study was an investigation of epiphyte communities. In each of the plots mentioned above, five mature trees were selected and the epiphyte community sampled by a 25 x 10 cm quadrat attached to the trunk at about chest height. This was repeated at a number of aspects on each tree to characterize any variation in the community. One of the plots was set up in high altitude bamboo forest; bryophytes were present on the stems particularly around the rough nodes.

It was decided that two members, Nick and Ron, accompanied by local trackers, would make an excursion into the interior; a day to walk in, a full day collecting and the third day to walk out. Two memorable nights were spent under canvas deep in the rainforest, all too aware that the tents were pitched across a regularly used elephant track. Luckily for us they didn't pass this way again, at least while we were there. In this part of the forest, large buttressed trees were common having escaped the deprivations of loggers. Tree-ferns were also a prominent feature of this area, and the moss Rhizofabronia persoonii appeared to be restricted to their fibrous stems. Epiphylls were common, with many representatives of Lejeuneaceae, including Taxilejeunea pulchriflora, Colura tenuicornis and Odontolejeunea lunulata, all unrecorded for Uganda. Several epiphyllous Daltonia spp. were also collected. On our way out of the forest we saw fresh gorilla nests, and it was quite a thought that we had been sleeping just a few hundred metres away from these incredible animals.

The number of published taxa from Uganda prior to our visit is something in the order of 362 mosses and 156 liverworts. Bryology in Uganda dates back to the early 1800s a period when some type specimens were published. Several collections have been made since, for example in the 1920s and 1930s, and with a particular increase in activity in the 1950s and 1960s, just before Independence and the Amin era. A large number of collections reside in the British Museum (Natural History), some named, but many not. Brian O'Shea has started working on these collections. Makerere University also houses a small collection of bryophytes from Uganda, some with familiar collector names, such as Alan Crundwell and Francis Rose. However most of these are also un-named. It is early days yet with the naming of our material, but many species are turning out to be new to Uganda, and for mosses the total is now in excess of 400 and for liverworts over 200.

All those who took part in the expedition had memorable experiences. For me, and I suspect others too, it was to see, at close range, a family of mountain gorillas set against the backdrop of their montane rain forest home.

Finally I would like to say many thanks to Nick Hodgetts and Martin Wigginton who did virtually all the organisation of the expedition, both before we left these shores and in Africa.