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Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper examines the changes in land use/cover types in the degraded environment of central Tanzania over the last 45 years, and how such changes have influenced agricultural and livelihoods sustainability, especially in the Irangi Hills. Changes of land use/cover were measured through aerial photographs interpretations, while local perceptions and description of change were addressed through household interviews and field observations. The results of this study show that there have been variations over the years in terms of both the areas and spatial distribution of cultivated fields. The total land cultivated increased from 31% in the late 1970s to 35% in early 1990s, mainly because of agricultural expansion to sandy watercourses and former grazing areas. Water courses shrank by 55% between late 1970s and early 1990s providing new areas for cultivation. Over the last 45 years, the open and wooded grasslands, and tree-cover types covered about 40% of the total land area, ranging from 29% in 1960 to 43–45% between late 1970s and early 1990s. Spatial and temporal distribution of the cultivated fields and other vegetation cover types were influenced by differences in the scale of land degradation, and the soil-conservation initiatives that have been implemented. With increasing pressure on the land, however, sustaining livelihoods through agricultural production in the area remains a critical challenge. [ABSTRACT FROM AUTHOR]

The paper is based on an on-going 3-year study in the wetland communities of Kampala. The study uses participatory methods and aims to contribute to (i) the development of low-income wetland communities, (ii) to prepare these communities to become less dependent on wetlands without receding into poverty, and (iii) the better management of the wetlands. The communities in direct dependence and intimate interaction with Nakivubo wetlands are mainly poor, live and work under hazardous conditions, and their activities pose a threat to the ecological function of the wetlands. Yet these wetlands are important for filtering the city’s waste and storm water before it flows into Lake Victoria’s Murchison Bay, which is Kampala’s source of piped water. Government approaches to the problem of wetland encroachment have largely failed because they are confrontational, and are not consistent or participatory. The study has in the first year conducted a series of activities including stakeholder analysis, resource analysis, livelihood analysis, a questionnaire survey and action planning. Preliminary data show that wetland dependency is very high among the poor nearby communities. They practice cultivation, brick-making and harvesting of wetland vegetation. However, these activities are under threat because wetland resources are dwindling due to increasing population and over-use. Livelihoods are threatened not only by the decreasing productivity of the wetland, but also by the ever-present government threat to evict wetland encroachers to restore its ecology. The study therefore works with communities to prepare for less dependence on wetlands so that they do not suddenly recede into worse poverty if they are evicted. They formulate strategies to enhance alternative livelihood, and for management of the wetland. Action plans have been formulated to address the situation through a newly created association. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The role of domestication in conserving indigenous plant diversity on farmlands was studied in West Usambara Mountains, Tanzania by structured, semi-structured and unstructured interviews; participant observation; literature review and botanical identification in March 2006. There was high diversity of indigenous plant species on farmlands (73%) compared with exotics (27%). For the number of plants per species, a small proportion of indigenous plants (14%) were recorded compared with exotics (86%). Although the number of domesticated indigenous plant species has declined by 8% between 1998 and 2006, still 96% of the respondents practise domestication and they have domesticated at least one indigenous plant species each. Gender equity in domestication is lacking given that male-headed households had domesticated significantly more plant species on farms than female-headed households. Sustainability in domestication is questionable because of increasing number of exotic plants of very few species on farmlands, the phenomenon that encourages monoculture, thus threatening conservation of species diversity in inhabited areas. Suggestions for promoting domestication as an important indigenous method for conserving biodiversity are given, including the need for more number of studies to explore the biodiversity of other organisms associated with the domesticated indigenous plants. [ABSTRACT FROM AUTHOR]

This paper addresses the effect of human activities on the density of large mammals in the Dzanga-Ndoki National Park and the adjacent Dzanga-Sangha Reserve in the Central African Republic. Between six and eight 20 km long permanent transects were walked on a monthly basis from January 1997 to August 1999 to assess large mammal populations as well as human intrusion. There were no obvious seasonal or monthly trends in elephant, gorilla or non-human primate densities. Overall, it appears that human activities negatively influence the distribution of most of the large forest animals in Dzanga-Sangha. Elephants in particular were significantly less common in areas used by humans, but also other species such as non-human primates showed lower densities closer to the main road and the town of Bayanga. This study confirms the findings of previous studies that roads have a negative impact on wildlife populations. Results of this study stress the need for conservation of large uninterrupted forest blocks to maintain wildlife populations at normal levels. Simply creating roads, even within a protected Central African forest, is likely to have negative impacts on wildlife populations. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A checklist of Odonata has been compiled for Kenya. It is based on an inventory of museum material, publications and personal observations made between 1978 and 1997. Changes of scientific names and synonyms are documented. The list contains 194 valid dragonfly species recorded for Kenya. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a practical tool that can assure comparable metrics for the age of forest elephants at the Dzanga Clearing in the Central African Republic. It mentions that reliable individual identification was facilitated by making an identity card as every individual was encountered, recording physical features such as pattern of ear tears and sex. It states that adult males and females older than 40 years averaged 2.32 meters (m) and 1.97 m, respectively.

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Lake Nakuru, Kenya, is one of a series of saline–alkaline closed basin lakes in the eastern arm of the Rift Valley. The lake has been variously described as ‘ the lake of a million flamingos’ and ‘the Worlds greatest ornithological spectacle’ and is bedrock to the areas’ tourism. The lake was designated a bird sanctuary in 1960, a National Park in 1968, first rhino sanctuary in 1987, first Kenyan Ramsar site in 1990, an Important Bird Area in 1999 and a world-class national park in 2005. Over the last 40 years, its basin has been heavily settled, extensively cultivated, urbanized and industrialized. Environmental problems include poor agricultural practices, human encroachment, pollution, wildlife mortality/morbidity, human/wildlife conflicts, poverty, ethnic tensions and land clashes and lack of adequate legal and policy framework. Approaches to conservation have been initiated against identified existing problems and constraints. These approaches are (i) organizational and institutional development; (ii) hot spots and pollution loads management and (iii) catchment and park management. Constraints have been identified as unclear demarcation of responsibilities, lack of budget, skilled staff and know-how and lack of environmental standards and regulations. The impacts of ecosystem changes on people’s lives and livelihoods are discussed. [ABSTRACT FROM AUTHOR]

In developing countries, participatory land-use planning is seen as a panacea to mitigate land-use conflicts and enhance land productivity. This assumption has not been thoroughly tested in wildlife corridors. Three villages were selected for this study. Several methods were used to provide indication of the performance of the plans against their stated objectives of mitigating conflicts and conserving wildlife corridors. Three hundred and fifty-eight households and eight park and extension workers were interviewed. In addition, focus group discussion with the nomadic Barabeig, field assessment and review of land-use plan/general management plan reports were carried out. Results reveal that land-use plans failed to achieve their set objectives. For example, 75% of the households held this view. Major causes of failure were insufficient participation by stakeholders in the planning process, lack of robust, transparent and accountable implementation strategies, inadequacy of qualified staff and lack of ‘holistic approach’ to the planning process. Taking these findings into account, an improved buffer zone land-use planning framework is suggested. For the framework to enhance both conservation and development and to enable policies and legislation, equitable benefit sharing and conservation education, initiation of compensation schemes for depredation caused by wild animals and intensification of patrols are required. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Traditional reserved pastures namely 'Olopololi/Alalili' for Maasai, 'Ngitili' for Sukuma and 'Milaga' for Gogo have been in use among the pastoral and agropastoral communities for many years. These reserves provide dry season feed for ruminant livestock especially cattle, sheep and goats. Apart from the provision of forage materials, these reserves provide fuel wood, construction material and medicinal plants. These traditional forage conservation practices also contribute to soil conservation and forage species biodiversity. However, studies conducted in these traditional forage reserves at Tingatinga (Maasai), Makang'wa (Gogo) and in Mwamishali/Mwanyanhina (Sukuma) in Tanzania show limitations of the reserves especially, in providing adequate dry matter and proteins for both maintenance and production of livestock. Nevertheless, there are opportunities for improvement on these traditional practices through introduction of improved grasses, legumes and tree/shrub species as well as proper maintenance of the superior local species and cultivars. [ABSTRACT FROM AUTHOR]

The article focuses the roundtable discussion related to ecology in Africa. During the discussion, attendees suggested that the term "Capacity Building" for biodiversity conservation be rephrased as "Capacity Enhancement" because there is knowledge already vested in people. The event also presented ecology research, including topics on the importance of monitoring mammals and birds in Eastern Africa and the significance of scientific and reference collections of animals and plants for biodiversity identification and research.

This study monitored the phenology of fruit and leaf of 575 chimpanzee food trees (40 species belonging to fifteen families) in the Budongo Forest Reserve (Uganda) from June 1999 to June 2006. We also monitored the phenology of all fig species in the study area. Fruit quantity varied significantly between species and seasons, with peak during wet season (April–June). The number of tree species in fruit correlated positively with rainfall and was higher during rainy season than dry season. Ficus species had exceptionally high fruit quantities ranging from 400 to 650,000 fruits per tree in a single production period. Leaf flushing peaked during late dry season and early wet season (February–April). Mature leaves were available at all seasons, even when young leaves were emerging. Only Ficus sur, Broussonetia papyrifera and Celtis gomphophylla had fruits throughout the year, and six species did not produce fruits during the study period. Of the twelve species that fruited between 40 and 58 months, three are very important timber species and seven were once killed with arboricides. We conclude that the long-term survival of chimpanzees in tropical forests requires conservation of their food trees. Résumé Cette étude a suivi, de juin 1999 à juin 2006, la phénologie des fruits et des feuilles de 575 arbres qui servent de nourriture aux chimpanzés (40 espèces appartenant à 15 familles) dans la Réserve Forestière de Budongo (Ouganda). Nous avons aussi suivi la phénologie de toutes les espèces de figuiers présentes dans l'aire étudiée. La quantité de fruits variait significativement selon les espèces et les saisons, avec un pic pendant la saison des pluies (avril - juin). Le nombre d'arbres en fructification était positivement corrélé avec les chutes de pluies et était plus élevé pendant la saison des pluies qu'en saison sèche. Les Ficus avaient des quantités exceptionnelles de fruits, allant de 400 à 650.000 fruits par arbre en une seule saison de production. La production de feuilles était au maximum en fin de saison sèche et début de saison des pluies (février – avril). Des feuilles mâtures étaient disponibles en toutes saisons, même lors de la parution de nouvelles feuilles. Seuls Ficus sur, Broussonetia papyfera et Celtis gomphophylla portaient des fruits toute l'année, et six espèces n'ont pas produit de fruits du tout pendant toute la durée de l’étude. Des douze espèces qui ont fructifié pendant 40 à 58 mois, trois sont très importantes pour leur bois et sept ont été tuées par des ‘arboricidesg’. Nous concluons que la survie à long terme des chimpanzés dans les forêts tropicales requiert la conservation des arbres qui leur servent de nourriture. [ABSTRACT FROM AUTHOR]

Soil is a living entity, comprising an inseparable mixture of solid, liquid and gaseous phases, and diverse fauna and flora, the below ground biodiversity. The macrofauna consists of animals longer than 4 mm or wider than 2 mm, which are easily located by the naked eye and include arthropods, molluscs and earthworms. This review is aimed at developing an inventory of the present knowledge about macrofauna in ecosystems in Uganda and identifying future priorities for research, application and capacity building. It is noted that there are a few assessments of soil macrofauna, diversity and abundance made for different habitats. Similarly, studies on their importance in ecosystems, distribution patterns, management, linkage with above ground biodiversity and effects of land use on them are deficient. Further, there is little documentation of farmers’ knowledge and practices related to soil macrofauna management and conservation. It is also noted that the current gaps in the soil macrofauna data and information have been caused by lack of capacity and expertise to identify, evaluate and manage this resource. More research and training in the taxonomy, ecology, economic evaluation and management of this fauna are suggested. [ABSTRACT FROM AUTHOR]

We studied the social system and time budget of kob antelopes in the Comoé National Park, Côte d'Ivoire from March 1993 till May 1998, a population that is suffering from heavy over-hunting, to assess information about the effects of population decrease and its relevance for conservation of this antelope population. Single animals accounted for the majority of observed kob antelopes. Time allocated to certain behavioural traits depended on group size, with animals in smaller units spending less time on behaviours sensitive to predation risk. Single animals allocated far less time to ruminating and feeding being more vigilant and walking more. Groups were highly fluid and associations between individuals could be predicted by home-range overlap among females but not for female/male associations where association indices might be influenced by reproductive aims. Frequency of social groupings did not change compared with earlier studies when population density was much higher. However, compared with these studies maximum group size decreased, and smaller groups became more abundant. The observed effect of group size on the time budget of kob antelopes in combination with a steady decrease in group size because of reduction in population size might have a severe impact on the long-term persistence of the studied kob population due to anticipated aggravated predation effects. As males form the majority of single animals, putting them on higher predation risk, number of males decreases more rapidly than the number of females, which might eventually lead to a collapse of the kob population. Résumé Nous avons étudié le système social et l'emploi du temps des antilopes cobes dans le Parc National de Comoé, en Côte d'Ivoire, entre mars 1993 et mai 1995. C'est une population qui souffre d'une grave sur-chasse, et nous voulions évaluer les informations sur les effets de la diminution de la population et leur pertinence par rapport à la conservation de cette population d'antilopes. La majorité des observations de cobes concernaient des animaux solitaires. Le temps consacréà différents types de comportement dépendait de la taille du groupe, les animaux faisant partie des plus petits groupes allouant moins de temps à des comportements sensibles au risque de prédation. Les animaux isolés passaient beaucoup moins de temps à ruminer et à se nourrir car ils étaient plus vigilants et se déplaçaient davantage. Les groupes étaient très fluides, et on pouvait prévoir les associations entre individus femelles par le recouvrement de l'occupation spatiale des femelles, mais pour les associations mâles-femelles, les indices peuvent être influencés par des buts reproducteurs. La fréquence des regroupements sociaux n'a pas changé par rapport aux études antérieures, quand la densité de la population était beaucoup plus élevée. Cependant, par rapport à ces études, la taille maximale du groupe a diminué, et les plus petits groupes sont plus abondants. L'effet observé de la taille du groupe sur le budget temporel des antilopes cobes, combinéà la diminution très nette de la taille des groupes due à la réduction de la taille de la population, pourrait avoir un impact sévère sur la persistance à long terme de la population étudiée car on peut s'attendre à des effets plus graves de la prédation. Comme les mâles forment la majorité des individus solitaires, ce qui les met plus en danger face aux prédateurs, le nombre de mâles diminue plus vite que celui des femelles, ce qui pourrait conduire à l'effondrement de la population de cobes. [ABSTRACT FROM AUTHOR]

The tilapiine fish Oreochromis esculentus, is endemic to only lakes Victoria and Kyoga and a few satellite lakes in the two lake basins. It was the most important commercial fish species during the first half of the 20th century in the two lake basins but because of over-exploitation and competition with introduced tilapiines, its stocks declined and, by 1980s, O. esculentus was virtually absent from the two main lakes. Lakes Mburo, Kachera, Kayanja and Kayugi in the Lake Victoria basin, and Nabisojjo, Kawi and Lemwa, in the Lake Kyoga basin, where remnants of the species survived were investigated using experimental fleets of gillnets from 1997 to end of 2002 with the objective of determining the species length frequency distribution, condition factor, feeding and breeding to guide its management, conservation and enhancement. Fish caught in Lake Kayugi, where diatoms dominated in the stomach contents attained the largest size, were most fecund and had a high value of condition factor K. These findings suggest that diatoms were vital in the survival of O. esculentus. However, with the recent shift of algal communities from diatoms to blue-green algae in most aquatic systems, assimilation of blue-green algae by O. esculentus should be investigated. Résumé Le tilapia Oreochromis esculentus est endémique des seuls lacs Victoria et Kyoga et de quelques lacs satellites dans leurs deux bassins. C’était la plus importante espèce commerciale pendant la première moitié du 20ème siècle dans ces deux bassins mais, en raison de la surexploitation et de la compétition avec des autres espèces de tilapias introduites, les stocks ont décliné rapidement et, au cours des années 1980, O. esculentus a pratiquement disparu des deux lacs principaux. Les lacs Mburo, Kachera, Kayanja et Kayugi, dans le bassin du lac Victoria, et les lacs Nabisojjo, Kawi et Lemwa, dans le bassin du lac Kyoga, où il reste quelques survivants de l'espèce, ont étéétudiés de 1997 à la fin de 2002 en utilisant des flottes expérimentales de filets maillants, dans le but de déterminer la distribution de la fréquence des tailles de l'espèce, les facteurs déterminant sa condition, son alimentation et sa reproduction, pour orienter sa gestion, sa conservation et sa consolidation. Les poissons pêchés dans le lac Kayugi, où les diatomées dominent dans le contenu stomacal, atteignaient la plus grande taille, étaient les plus féconds et avaient une valeur élevée du facteur K de condition. Ces découvertes suggèrent que les diatomées sont vitales pour la survie d’ O. esculentus. Cependant, avec le récent glissement des communautés d'algues des diatomées vers les algues bleues dans la plupart des systèmes aquatiques, il faudrait étudier l'assimilation des algues bleues par O. esculentus. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

SummaryThis study of biomass densities of wild animals and domestic stock was carried out on the Lolldaiga Hills ranch in the Laikipia District, Kenya, between 1989 and 1995, as part of the study of the ecology of leopards and their impact on the working ranch. The ranch is set amongst the Lolldaiga Mountains, north-west of Mount Kenya, and lies in ecological Zone IV. The vegetation in the area was classified as a scattered tree grassland. The weighted mean annual rainfall was 554 mm. The ranch carried 1543 kg km-2 of wild animals and 6512 kg km-2 of cattle and sheep. The ranch has produced beef, milk and wool since its foundation over 70 years ago, with a steadily maintained output and without any apparent degradation of the land. The milk production of normally over 450,000 kg per year was reduced, or ceased, in periods of drought and may represent a useful ‘safety valve’. The feasibility of multiple land use and conservation of wildlife are discussed. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There has been considerable uncertainty about the abundance estimation of Loxodonta africana within tropical lowland moist forests in Zaire. We surveyed a 15,570 km2 area within the forests of eastern Zaire using transect sampling methods and estimated the elephant population to be 3720 (range 2300-5000) individuals. Dung pile densities were significantly different between adjacent settlement, deep forest, and deep forest core strata, with the most remote area harbouring the highest density. Evidence of elephant poaching was encountered throughout the survey area suggesting that elephant populations continue to be at severe risk. [ABSTRACT FROM AUTHOR]