A note on the chimpanzee ecology of the Ugalla Area,Tanzania

Results of a nine-day survey of the chimpanzee habitat in Ugalla area of western Tanzania in 1975 is reported. The most dominant vegetation of the area wasJulbernardia globiflora woodland. Evidence of chimpanzees, both indirect (such as beds, faeces, and food remnants) and direct (calls and actual observation), suggests that chimpanzees are sparsely distributed throughout the area, but that they disproportionately useBrachystegia bussei woodland along escarpments andCynometra-Albizzia riverrine forests. The hilly country of Sisegwa/Mnyangwa was the only area where chimpanzees appeared to be comparatively abundant. Mammal hair found in faeces indicates mammal-predation by the chimpanzees in this area. Hard-shelled fruits ofStrychnos were apparently bitten open without the use of extra-somatic objects. The food repertoire included fruits of the generaAzanza, Canthium, Cordia, andTamarindus.     

Spatial pattern,regeneration and growth rates of Brachystegia spiciformis and Julbernardia globiflora

Past work on tree-to-tree interactions in semi-arid savannas, through the use of nearest neighbour analysis, has shown both a regular dispersion pattern and a positive correlation between the size of a tree and the distance to its nearest neighbour. From these results, the importance of competition has been inferred. In the present study, tree-to-tree interactions in a mesic savanna woodland at Marondera, Zimbabwe, dominated by relatively small-sized individuals of Brachystegia spiciformis and Julbernardia globiflora, were examined. Results show that the regular dispersion pattern is uncommon; that there are few significant positive correlations between size of individual and distance to nearest neighbour; and that growth rate is not consistently correlated with size and distance of nearest neighbour. Results of a study of regeneration relative to canopy cover suggest a possible mechanism for these findings: unlike semi-arid savannas, young plants often grow in under-canopy environments so that early spacing of young trees does not occur. Significant positive correlations between the size of a tree and the distance to its nearest neighbour were found in a stand of larger, presumably older, trees, suggesting that such a relationship only develops in mesic miombo woodland through a thinning process as the trees mature. Familial clumping, which is common in the study area, may mask spatial patterns.Abbreviations RBAI Relative basal area increment     

Ectomycorrhizae in coastal miombo woodland of Tanzania

Summary Ectomycorrhizae were found in root samples of the treesAfzelia quanzensis Welw. andBrachystegia spiciformis Benth. (Caesalpiniaceae), collected in the coastal miombo type woodland 50 km west of Dar-es-Salaam, Tanzania. Root nodules with a structure resembling that of nitrogen-fixing root nodules of other leguminous plants were observed in theA. quanzensis material. The climate of the locality is rather dry, and strongly seasonal. In the tropics, ectomycorrhizae have previously been found only in humid or rain forest climate zones.     

A preliminary survey of epiphytes in some tree canopies in Zambia and the Democratic Republic of Congo

The vertical distribution of the density and richness of vascular and nonvascular epiphytes on some mature trees was studied in two 1 km² plots in Miombo Woodland in Zambia (n = 20) and the Democratic Republic of Congo (D.R.C.) (n = 20). The aim was to assess the diversity of arboreal epiphytes and to investigate general distribution patterns of epiphytes along some individual mature phorophytes. Species richness was low on both sampling sites (24 in D.R.C. and nineteen in Zambia) with Orchidaceae being the richest family. Epiphyte density for both sampling plots was high with 92% of the available surface area being occupied. Lichens showed the highest density of 67.2% followed by moss 18.4%, orchids 7.9% and ferns 6.5%. Species richness and density showed a clear zonation within the canopy. Richness and density peaked in the upper and mid‐canopy and was positively correlated with available surface area, branch aspect and to some extent bark pH, but not with bark texture. This study demonstrated that tree canopies can harbour a diversity of epiphyte species, and the findings constitute baseline information in such environments.     

The Short-term Impact of Forest Fire on Soil Invertebrates in the Miombo

A study was conducted in eastern Zambia to assess the impact of fire on soil invertebrate communities between December 2003 and November 2004. Soil samples were collected 4 times from secondary miombo forest patches that were burnt in July–September 2003 and 2004 and patches not affected by fire. Macro-invertebrates were hand-sorted from soil samples and their population densities computed. The total number of orders per sample and the population density of Annelida, Chilopoda, Arachnida and some Hexapoda were lower under burnt forest patches compared to unburnt ones throughout the study period. Although the difference between burnt and unburnt patches in populations of other taxa such as Lepidoptera and Diptera remained below the threshold of statistical significance, fire appeared to have reduced their densities. It is concluded that fire can alter the structure of soil invertebrate communities through direct mortality or by its effect on availability of food resources. Further studies are needed to establish the linkage between fire, invertebrate community structure, ecosystem processes and floristic composition of the miombo.     

Community-based Monitoring of Natural Resource Use and Forest Quality in Montane Forests and Miombo Woodlands of Tanzania

A community-based monitoring system that focuses on natural resource use and forest quality in montane evergreen forest and miombo woodland areas was developed and implemented in 23 villages in 2002 as part of a participatory forest management regime in Iringa District, Tanzania. The scheme was developed to suit the needs and capacities of locally-elected natural resource committees managing and monitoring natural forests. Rather than measuring biodiversity, the monitoring is focused on resource extraction and disturbance. High levels of commitment to the monitoring were displayed by village level managers, and the preliminary feed-back indicates that the monitoring scheme provides them with the relevant information needed to suggest appropriate management interventions. While external support has been essential to cover development costs, natural resource revenue generated at village level can provide most of the running costs. Once developed, the scheme can, however, be transferred to similar areas at significantly lower costs that can be met by Tanzanian District budgets. Natural resource revenue generated from montane forests is generally much lower than in woodland areas due to restrictions on resource extraction imposed as a consequence of national and international interests. Opportunities to provide economic incentives for montane forest managers through direct utilisation of the resource are limited and it remains to be seen whether other non-economic incentives can sustain long term commitment in these biodiversity rich areas. Findings indicate that the key elements of this local resource utilisation monitoring scheme are simplicity, incentive mechanisms, transparency and accountability, and autonomy for local managers. However, the methods may not provide sufficient data on changes in biodiversity values in the high value forests and may need to be augmented by conventional monitoring by scientists funded by national or international institutions. Elements of the scheme are now being institutionalised within the forestry sector in Tanzania.     

Tree species composition and diversity in Miombo woodlands between co‐managed and government‐managed regimes,Malawi

Comparative information on the composition and diversity in tree species associations in Miombo woodland is limited. This study assessed how tree species associations across forest reserves of Miombo woodland in Malawi varied in composition and diversity concerning site factors and resource use disturbances under co‐management versus government management. Eighty nested circular plots, randomly selected in ArcGIS, were sampled to record stem diameter at breast height (DBH) of tree species: 0.04 ha for stems 5–29.9 cm DBH and 0.16 ha for stems ≥30 cm DBH. The recorded 109 tree species grouped into communities and 14 sub‐communities, using stem counts by species in TWINSPAN analysis. Sub‐divisions to level 5 showed eigenvalues ≥0.3, symbolising the stability of sub‐divisions. North/South sub‐divisions related to site factors; historical/current resource use influenced differences at levels 3–5. Species importance differed, indicating few important species in each sub‐community. Brachystegia and Julbernardia species showed importance across sub‐communities while Uapaca sansibarica in government management. Disturbances stimulated high species diversity. Recommendations include the need for a policy review towards group‐felling mature stands to stimulate regeneration and selective thinning of suppressed stems in stand development stages to maintain species diversity, productive recovery, diverse resource use value, and monitoring of harvesting impacts.     

The immediate effect of burning and ash-fertilization

Summary Changes in the vegetation and soil store of major nutrients were followed under the local practice of shifting cultivation. Changes in the soil store of N, P, K, Ca, Mg and Na were recorded under recently cleared forest before, 24 hours, and 40 days after the burning of vegetation of known biomass and chemical composition.The immediate increase of K and the delayed increase of P in the upper 50 cm—although equal to the content of the above-ground vegetation before burning—is not to be explained by the ash-fertilization alone. The immediate increase of K after burning was not observed after 40 days at any depth, and less Ca and Mg were found in the topsoil immediately after the burning and after 40 days, than before. Apparently mobilization and/or diffusion due to heat are important factors, even in the deeper horizons.