Search

Environmental sustainability is a huge challenge in Africa as the region is currently struggling to provide sustainable systems to support daily human activities. Such activities in many African organisations include paper‐based information storage and communication which are not ecofriendly and place a huge burden on forest resources. This study therefore focused on the implication of overusing paper in an African university. Fifty offices in the university were surveyed and 59 questionnaires administered. The questionnaires were transcribed and analysed using both textual qualitative and quantitative analyses. The results showed that 6888 reams of paper (costing about 8 million Naira) are consumed annually by the university, translating to about 413 trees, which are enough to occupy a standard‐sized football pitch. It was also found that administrative staff members were generally Information Communication Technology (ICT) certified; however, many of them are still not well‐informed on the environmental implication of overconsuming paper even though they are largely aware of the benefits of paperless systems. Recommendations were offered on how to reduce the demand for paper by the university. This study is expected to create more awareness on the urgent need for African organisations to take environmental sustainability issues more seriously. [ABSTRACT FROM AUTHOR]

The wasps' nest was only about 15 cm from the water surface, but the growing vegetation structures in the floating mat may have prevented it from sinking further towards the water. GLO:7ZA/01dec20:aje12772-fig-0001.jpg PHOTO (COLOR): 1 Nest of Polistes paper wasps attached to remains of an herbaceous plant protruding from a transient floating vegetation mat in the Aluize, Mozambique (November 2017). [Extracted from the article]

The Critically Endangered Nubian Flapshell Turtle (Cyclanorbis elegans) is found in the White Nile River system in South Sudan and northern Uganda. Over the past few decades, its populations have sharply declined, primarily due to human-induced threats, leading to its near-extinction across almost its entire range. In this paper, we present the results of a comprehensive threat analysis undertaken to pinpoint the challenges confronting the species within its natural habitat, specifically in the only known sites where it currently exists. We aimed to develop a conceptual framework to understand causal relationships among driving forces, threats and the target species. This framework allows the visualisation and analysis of the web of intricate interactions that contribute to the species' decline and vulnerability. We convened a panel of experts who identified three primary direct threats to the Nubian Flapshell Turtle: (1) Sand mining (IUCN code 3.2); (2) Overfishing by native fishers and refugees (code 5.4) and (3) Habitat loss at nesting sites (code 7.3). Among these threats, overfishing had the largest geographical extension, the highest intensity and duration, while habitat loss occurred at the highest frequency. These threats varied significantly in intensity and frequency. Additionally, when assessing the overall magnitude of these threats, habitat loss and overfishing had the highest impact, with significantly higher scores compared to sand mining. Our experts also identified the underlying driving forces behind these threats: (1) Economic interests driving sand mining activities along the Nile; (2) The influence of civil conflict and refugee populations, which contribute to the demand for bushmeat; (3) the Chinese expatriates, that lead to overfishing; (4) The removal of bank vegetation serves as a catalyst for habitat loss at nesting sites. The resulting conceptual framework serves as a valuable tool for defining targeted conservation measures for each distinct threat. [ABSTRACT FROM AUTHOR]

Using the lens of the baobab tree, this paper explores the ecological outcomes of different tenurial arrangements and implications for resource sustainability. With the emergence of markets for baobab products, a central concern is to confirm whether use patterns differ across different tenure regimes and, if so, their ecological outcomes. The study is based on an ecological survey in Zimbabwe of 244 baobab trees located across three tenure regimes – communal, private and state – and also draws on interviews with key informants. The results suggest that tenure has a strong influence on the sustainability of baobab harvesting. Based on identified parameters of ecological sustainability, trees under state tenure were shown to be harvested unsustainably, and showed excessive bark harvesting, while those under private and communal tenure had fewer signs of debarking and produced more fruits, suggesting their use was more sustainable. Excessive bark harvesting was found to negatively affect fruit and bark production and, to a lesser extent, the overall health of the tree. The research illustrates that in order to understand ecologically sustainable use, an understanding of resource use patterns across different tenure regimes is crucial, suggesting the design of bespoke interventions to manage the use of natural resources in different tenure systems. [ABSTRACT FROM AUTHOR]

The paper assesses trends in use of earth observation data in wetland conditions monitoring and assessment in Zimbabwe from 1980 to 2019. Reviewed literature shows academia and research institutions (69.8%), government agencies (14%) and international development partners (16.3%) as the main users of remotely sensed data in wetland ecological assessments and monitoring. There is more reliance by the abovementioned stakeholders on freely available low‐cost resolution imagery from Landsat (62.9%) and Moderate Resolution Imaging Spectroradiometer (14.3%). Other stakeholders, however, are reliant on high‐resolution imagery like Rapid Eye (5.7%) and aerial photography (11.4%). Satellite images in wetland management in Zimbabwe are used for land use land cover change detection (42.1%), vegetation health monitoring (21.1%), water quantity monitoring (5.3%), water quality monitoring (13.2%) and wetland mapping (18.4%). The identified challenges faced by different stakeholders to effectively utilise EO data include high cost of high‐resolution imageries, limited expertise, inadequate equipment and software. Since the cost of high‐resolution satellite imagery mainly constraints the acquisition of suitable satellite data to assess the small wetlands that dominate Zimbabwe's landscape, there is need to promote use of recently launched freely available high‐resolution Sentinel data to improve the ecological assessment of wetland conditions. [ABSTRACT FROM AUTHOR]

The Eastern Arc Mountains are one of the most important ecosystems that conserve biodiversity in the world. These ecosystems are threatened by the increasing occurrence of wildfires. Nevertheless, there is inadequate information useful for the development of effective strategies to prevent or respond to future fires. This paper analyses the current extent of dry season fires, underlying causes and the effectiveness of the fire management strategy being implemented in and around the Uluguru Nature Forest Reserve (UNFR) between 2016 and 2021. Differenced Normalised Burn Ratio derived from Landsat satellite images was applied to determine the extent of burned areas, and focus group discussions were held to determine the underlying causes of fires and the extent of implementation of fire management strategies. About 2% (472 ha) of reserved UNFR and 5% (2,854 ha) of unreserved forests were burned in 2017. Some of the fires impacted on 60% (370 ha) of the grassy Lukwangule plateau, which is home to a fire‐sensitive endemic species. The underlying causes of fires varied spatially across the mountains but generally, fire escaping from farm preparation and hunting activities were found to be the most prevalent. On average, survey participants perceived that fire management strategy objectives were achieved by only 29% mainly constrained by a shortage of financial and human resources. Our findings suggest that ignitions and fire spread in UNFR could be prevented or controlled through sustainable funding of fire management activities and the effective engagement of local communities in the management of the reserve. [ABSTRACT FROM AUTHOR]

Large mammals consist of a wide variety of animal species ranging from lower herbivores to top carnivores (Collier, Ditchkoff, Raglin, & Smith, 2007). Natural habitats are disappearing at an alarming rate due to the expansion of human habitats, which account for the loss and reduction in many large mammalian species (Vaughan, Ryan, & Czaplewski, 2000). Therefore, the aim of this paper was to record the large diurnal mammals of Nechisar National Park and to identify the major human activities that threaten this cohort of species and their habitat. Among the order Artiodactyla, the family Bovidae was represented by seven species followed by the order Suidae ( I n i = 2) and the order Hippopotamoid ( I n i = 1). [Extracted from the article]

Understanding homestead tree holdings is important for developing local conservation and livelihood strategies. However, relative to urban homesteads, tree holdings in rural African homesteads remain little studied, especially in semi‐arid settings. Using ecological and household surveys, this paper examines homestead tree composition, uses and challenges in Checheche, Zimbabwe. In total, 1,594 trees were encountered across 147 homesteads. Nearly, all homesteads (99%) had trees, and most of them were primarily planted for fruits and shade. Fuelwood, traditional medicines, windbreak and homestead decoration were considered as secondary benefits. Overall, tree density was approximately 112 trees/ha, with an average of 11 ± 7.1 trees per homestead. Homestead tree holdings were explained by age and gender of respondent, homestead ownership and importance attached to and knowledge of trees. Challenges to tree planting mentioned include termites, diseases, livestock damage, high temperatures, water shortages and poor quality soils. Overall, this study shows that homestead tree planting is widespread in semi‐arid rural settings but constraints to tree planting ought to be addressed to optimise the benefits from trees. Further research is needed to fully understand the socioecological context that explains tree survival, as a basis for developing interventions for enabling homestead tree planting. [ABSTRACT FROM AUTHOR]

In the context of recent climate changes and their impact on the vegetation cover in the southern shore of the Mediterranean, this paper deals with the potential distribution in the present and the future of the Aleppo pine in the north‐east of Algeria. Accordingly, this study focuses on modelling of the spatiotemporal distribution of the Aurasian Aleppo pine, by means of MaxEnt program. The models developed with MaxEnt showed good predictivity with AUC > 0.80 for the RCP 4.5 and RCP 8.5 scenarios projected, respectively, for 2055 and 2085. The results showed that the annual thermal amplitude followed by altitude appear to be the main factors of the spatiotemporal distribution of Aleppo pine in the study area. Under current conditions, only 20% of the territory seems favourable to the presence of the Aleppo pine. However, future predictions expect an extension of the areas classified as "moderately favourable" to the Aleppo pine. In response to climate changes, the Aurasian Aleppo pine may display two contrasted tendencies: a progressive evolution in the north, and a regressive evolution in the south of the Aurès region as well as a displacement of suitable areas for Aleppo pine to the north. [ABSTRACT FROM AUTHOR]

The main aim of this paper was to evaluate the use of OLI spectral data as a tool to assess the steppe vegetation in a conservation context. The field sampling was conducted for two specific areas of treatment (a) an exclosure area and (b) a free grazing area. After testing several vegetation indices (VIs), the optimal results were obtained for the Normalised Difference Vegetation Index (NDVI)‐based aboveground biomass model with r2 = 0.61 and r2 = 0.72 for total and perennial biomass, respectively. No difference between observed and predicted total and perennial biomass was found (p = 0.700 and p = 0.306, respectively). The comparison between the two treatments using the field sampling revealed a significant difference on total plant cover (p = 0.016) and total biomass (p = 0.005), with a plant cover of 50.6% and a biomass of 325.771 kg dry matter per hectare (kg DM ha−1) on average in grazed area and 66.9%, 1,407.869 kg DM ha−1 in exclosure. Finally, a concordance is noted between the results obtained by the NDVI‐based biomass model and the field sampling‐based biomass. [ABSTRACT FROM AUTHOR]

Camera traps are very widely used to monitor the presence of animals and record their behaviour. Setting them up properly enhances their performance and data yield. The paper describes how camera traps work and gives basic advice on camera selection, setting up camera traps for various purposes, protecting them from animals, keeping them working and troubleshooting. A camera trap's capture of a still image or video is triggered by a passive infrared detector that responds when something hotter or colder than the background moves in its detection zone. Target detection is camera traps' weak point, and they need to be set up so that animals move across their detection zone rather than towards or away from the camera. Short trigger and recovery times are preferred. After dark, camera traps illuminate the subject with infrared light that is difficult for animals to see, or white light if colour images are required. During the day, stills and video are captured in colour, and at night in monochrome under infrared, or in colour with white illumination. Where cameras need to be sited depends on study design. Camera performance is sensitive to the height and angle that they are mounted at; maximum detections come from cameras just below the target's shoulder height, aimed horizontally. To avoid large numbers of false triggers, trim vegetation in the detection zone that might be moved by the wind. Keep cameras clean and change batteries frequently. [ABSTRACT FROM AUTHOR]

In a paper published fifteen years ago, Gorman et al. ( Nature 391, 479-481) made precise claims about how sensitive the African wild dog is to kleptoparasitism by spotted hyaenas Crocuta crocuta and lions Panthera leo. These claims are regularly referred to in the literature, and so far, they have remained unchallenged. However, careful perusal of their paper and analysis of the available data on energy intake and expenditure by wild dogs show that their claims are unfounded. Contrary to Gorman et al., wild dogs can usually take loss of food by kleptoparasitism in their stride. We present the calculations of the energy budget of wild dogs that remain implicit in the paper by Gorman et al. [ABSTRACT FROM AUTHOR]

Abstract: Large areas of the bushveld bioregion are converted from natural rangeland to cultivated fields for economic purposes. Conversion of grasslands to agricultural land alters the vegetation structure, plant species composition and ecological functioning. The aim of this paper was to evaluate the effectiveness of different seeding densities to enhance the restoration of old cultivated fields in Marakele National Park. Before these areas along the Motlhabatsi River were incorporated into the Park they were used for cultivation of crops. In an attempt to restore these areas to an improved condition, this pilot study was undertaken to determine best practice. One study area comprising two experimental sites and one control site were selected. A seed mixture consisting of natural grass species to the area was selected and sown at two different seed densities. The sites were monitored for a 2‐year period for species diversity and composition. Data were analysed using the analysis of variance (ANOVA), while species diversity was calculated for the different experimental sites using the Shannon–Wiener index. Limited differences were observed between the two seeding densities. The results indicate that seeding degraded grasslands in these bushveld areas enhance the diversity and evenness of the degraded land. [ABSTRACT FROM AUTHOR]

Following its introduction in the late 1960s, Broussonetia papyrifera L. Vent. Moraceae (paper mulberry) has emerged as a major exotic invasive species in Ghana's forest ecosystems. This study was carried out to assess the effects of B. papyrifera invasion on community composition in forest and forest-savannah transition ecosystems. Comparative and removal experiments were conducted in paired B. papyrifera invaded versus uninvaded plots. In the comparative assessment, species composition was found to be similar in both invaded and uninvaded plots. However, relative per cent cover of resident species and guilds including Chromolaena odorata, indigenous broadleaves and indigenous grasses were significantly lower in invaded plots. Seven months after B. papyrifera was experimentally removed from invaded stands, cover by indigenous broadleaves increased by 35%, as against only 5% in control plots at the forest site. However, at the transition site, the increase in per cent cover of indigenous broadleaves (18%) was not significantly different from control (2.5%) plots. We conclude that B. papyrifera has the capacity to reduce the abundance of indigenous broadleaf species, although its removal is more likely to favour regeneration in a forest than a forest-savannah transition ecosystem. [ABSTRACT FROM AUTHOR]

This paper provides an overview of some of the significant environmental problems in the Southern African region. The key problems highlighted are global warming and climate variability, loss of biodiversity, deforestation, desertification-land degradation, waste and littering, population growth, urbanization, pollution, poverty and health hazards. These problems present a challenge to governments and other players within and outside Southern Africa to seek for long-term solutions by addressing the root causes of these problems. The paper notes that although the environmental problems facing the Southern African region are being tackled at national, regional and international levels, there is more that can be done. At the national level, the different agencies and players, both within and outside government need to strengthen coordination and implementation of key interventions in different sectors in both rural and urban areas. At the African regional and international levels, there is a need to address geopolitical forces and issues that contribute to the underdevelopment of the African region. Among the major issues are poor terms of international trade, political instability, poverty, declining economic performance and international debt. [ABSTRACT FROM AUTHOR]

Community ecology and resource-partitioning patterns of African reptiles have been increasingly studied over the past 30 years. In this paper, I review these studies and provide a meta-analysis based on null models and Monte Carlo simulations (RA2 and RA3 algorithms) to compare patterns of resource partitioning among reptiles in tropical versus nontropical Africa. In general, studies on community ecology of African reptiles have had a strong impact on the global study of resource-partitioning patterns in ectotherms, with such authors as Robert Barbault and Eric Pianka being among the most famous having ever worked in Africa. Despite previous claims, in this paper I suggest that there is no true evidence that reptile biomass is depressed in tropical Africa in comparison with tropical regions of other continents. My null-model reanalysis of 32 independent study systems (twenty from tropical Africa and twelve from nontropical Africa) shows that resource-partitioning patterns are nearly always found in tropical assemblages of reptiles, although this cannot be said for nontropical assemblages of species. Microhabitat (especially for lizards) and food (especially for snakes) are the resource axes typically partitioned by African reptiles. [ABSTRACT FROM AUTHOR]

The Serengeti–Mara ecosystem in East Africa is a spectacular natural heritage endowed with diverse fauna and flora. The presence of the seasonally migrating wildebeest (Connochaetes taurinus) is a major boost for tourism. This migration however has enormous impacts to the ecosystem. Consequently efforts at monitoring the herd's migration trends and patterns remain a challenge to wildlife managers and ecologists in the region. In this paper, the relative influence of vegetation (normalized difference vegetation index), landscape and relief on herds migration routes are investigated and the migration routes simulated using GIS and remote sensing techniques. The results are compared with the annual mean route taken by the herds, as determined by radio tracking over the 1995–1997 period. Green vegetation availability is shown to be the major criterion in route choice. It is also shown that during the dry season phases of the migration (western trek, western corridor), the herd endures complex relief (complexity quantified based on slope and inter-visibility) in the search for greener grass. During the season of abundance (southern trek), relief becomes critical in making route choices, with herds avoiding difficult terrain, notwithstanding their relatively more abundant vegetation. The method proposed in this paper is viable for rapid prediction of approximate routes for the migrating wildebeest in different climatic conditions. [ABSTRACT FROM AUTHOR]

Species distribution models are often used in ecology to ascertain relationships between environmental variables and species presence. Modelling to understand this relationship can be used to aid conservation management strategies. In this paper, we applied the random forest classification method to predict habitat used by black rhino for browsing. The random forest model was created using detailed habitat data collected from Ol Pejeta Conservancy in Kenya. Variables from plots where rhino had been present were compared to those not used by rhino. Independent data were used to test the predictive accuracy of the rules generated. The model performed well with the independent test data, correctly classifying 69% of the sampling plots where black rhino were present. Important habitat features that affected rhino presence were browse availability and density of vegetation, with Vachellia drepanolobium (formerly Acacia) and Euclea divinorum being important components. The analysis also highlighted areas of potential high browse pressure, which should be the focus of continued monitoring and management. [ABSTRACT FROM AUTHOR]

The study of community composition shifts due to increased habitat modifications and deforestation is a primary issue in contemporary tropical community ecology theory. As the forest habitat conversion process has been very short in Africa relative to the evolutionary temporal scale, it is likely that animal communities are not at an equilibrium. The Upper Orashi Forest Reserve (Niger Delta region of Southern Nigeria) is a valuable case study as it is one of the few remnant deltaic swamp forest patches inside a highly developed and deforested region. In this paper, we investigated some aspects of the community ecology of reptiles of this forest area based on standardized field surveys across 2 6 study plots. Overall, we recorded 34 species, with the detected number of both species (34 versus 2 7) and individuals (562 versus 381) being higher during the wet season. Diversity/dominance diagrams showed similar trends in both seasons, but diversity measures showed that evenness was remarkably higher by wet season. Analysis of similarities (ANOSIM) confirmed that the species-richness estimate generated by Chao's index was significantly higher for the wet season. However, the profiles of the diversity curves were comparable in the two seasons. The proportion of forest-specialist species decreased compared to that observed at the same study area 15+ years ago, with a gradual process of biotic homogenization being apparent. [ABSTRACT FROM AUTHOR]

Old World vultures are in decline across their entire range. Although critical for the formulation of effective conservation measures, neither survival nor movement patterns of African vultures are adequately known. This paper presents survival and movement data on the African white-backed vultures ( Gyps africanus) from South Africa. Survival estimates were modelled on resightings of tagged vultures. Birds were captured en masse and resighted between November 2005 and December 2010. A total of 93 adult and subadult birds were fitted with uniquely numbered patagial tags, which were resighted 3707 times(mean of 39.8 resightings per bird). The programme MARK was used to estimate survival. The best model was one where survival and recaptures varied only with time (e.g. year). However, owing to the fading (illegibility) of tags in later years, the relationship with time is probably spurious. The second best model was one where survival and recaptures varied with age and time. Annual survival estimates increased from 85.2% in second-year birds to 99.9% in adults. This corresponds well with the survival of two other Gyps vultures that have been studied to date and underscores the point that additional mortality of adults in these long-lived species will result in rapid population declines. [ABSTRACT FROM AUTHOR]

Long-term wildlife monitoring programs are typically listed as a fundamental component of protected area (PA) management. Unfortunately, few PAs have wildlife population monitoring information available over extended periods of time, particularly in the many forested PAs throughout tropical Africa. Taï National Park in south-western Côte d'Ivoire is one of these few. Regular wildlife monitoring based on transect dung count sampling and direct observations began as early as 1977 in five sections of the park. In this paper, we present comparative descriptive results from two periods, 1977-1983 and 1995-2004. Several large mammal species, such as forest elephants and bongos, have experienced dramatic population declines over this time period, with some decline rates as high as 91%. Other species, such as duikers and leopards, seem to have better resisted the primary cause of these observed declines, hunting. In addition, we found that day counts delivered mostly significantly lower density estimates for several of the monitored species than night counts, which shows the importance of carefully interpreting the estimates from other studies. The continuation of wildlife monitoring will provide further insight into the efficiency of implemented park management with regard to the observed population changes. [ABSTRACT FROM AUTHOR]

Termites are important decomposers and 'ecosystem engineers' in tropical ecosystems. Furthermore, termite assemblages are sensitive to human land-use intensification and often termite density and the importance of soil-feeding termites decrease with land-use intensification. These changes in termite assemblages may also lead to a decrease in termite-mediated ecosystem processes (e.g. soil formation, cellulose decomposition). We compared density and functional composition of termites with cellulose removal from undisturbed primary forests to farmlands (Kakamega Forest, Western Kenya). In contrast to the expectation, we found no response of termite abundance along the gradient of land-use intensification. However, as expected, the relative abundance of soil-feeders decreased from primary forests to farmlands. In contrast, frequency of attack on tissue paper baits and removal of tissue showed a clear hump-shaped relationship to land-use intensification with high values in secondary forests. These nonconcordant patterns of density and functional composition of termite assemblages with cellulose removal by termites suggest that it may be misleading to infer changes in a process by the characteristics of the assemblage of organisms that mediate that process. [ABSTRACT FROM AUTHOR]

This paper reports the results of the first study on secondary seed removal of seeds dispersed by Sykes' monkeys ( Cercopithecus albogularis) using camera traps in Africa. Patterns of primary seed dispersal are often superimposed by secondary conveyance, emphasising the need to study these secondary processes carefully. As the agents and mechanisms of seed dispersal are often concealed, being carried out by cryptic or nocturnal animals in dense vegetation, camera trapping was deemed a viable means to investigate secondary removal of seeds disseminated by C. albogularis in the Western Soutpansberg, South Africa. Camera traps were established at preferred feeding trees of the focal Sykes' monkey group to identify animal species that remove seeds and fruits spat and dropped to the forest floor and seed removal observations were carried out. This method proved to be effective in identifying seed removers and also allowed to get indications about the quantities of seeds removed. Ten animal species were recorded visiting the trees, of which eight were observed removing seeds and fruits. Overall seed and fruit removal rates were high, indicating that the foraging behaviour of C. albogularis attracts many terrestrial frugivores. [ABSTRACT FROM AUTHOR]

Mount (Mt) Elgon forest in western Kenya is important for biodiversity, environmental protection and socio-economic development. Characterizing forest conditions is essential for evaluation of sustainable management and conservation activities. This paper covers findings of a study which determined and analysed indicators useful in monitoring disturbance levels in the Mt Elgon Forest. A systematic survey was carried out and covered 305 plots of 0.02 ha and 250 smaller nested regeneration plots along 10 belt transects that were distributed in five blocks within the moist lower montane forest type. Collected and analysed data include types of disturbance, tree species composition, abundance and logged species. Correlation breakdown among disturbance types revealed that, paths were indicators of the number of tree harvesting sites ( rs =1.00, P < 0.01) and of de-vegetated areas through grass harvesting ( rs = 0.90, P = 0.04). Solanum mauritianum Scop. was an indicator of old-charcoal production sites. Logging targeted 13 tree species and harvested trees with diameter at breast height above 20 cm. The most exploited species were Olea capensis L. and Deinbolia kilimandscharica Taub. All exploited species had low regeneration but tree regeneration was not an effective indicator of logging. [ABSTRACT FROM AUTHOR]

This paper describes a method of scoring the neck pattern of reticulated giraffes as a simple code that can be searched for in an Excel spreadsheet. This enables several hundred individual giraffe to be recognized and repeatedly found within a database. Possible sources of error are described and quantified. Data on group size, dispersal within groups and social network patterns are described. The latter is facilitated using Ucinet 6.85 for Windows, a software package that helps to visualize and analyse such networks. [ABSTRACT FROM AUTHOR]

The dung count method is widely used to estimate elephant numbers in forests. It was developed in the lowland forests of Central Africa but it is also used in Montane forests in eastern Africa. Using data collected on Mount Kenya and computer simulations, this paper explores the following issues associated with dung surveys in Montane forests: • High rainfall at 3000 m altitude on Mount Kenya was expected to accelerate dung pile decay but no significant difference was found between 3000 and 2500 m where less rain falls, possibly because high rainfall at 3000 m is counteracted by lower temperatures; • Physical obstacles make it difficult to walk long, straight transects in Montane forests. Deviating from a straight line pushes the distribution of distance measurements from dung piles to the transect centre line (pdist) towards a negative exponential (NE), which complicates data analysis and may give inaccurate estimates. Using short transects largely alleviate this problem; • Analysis of dung count simulations shows that the expected sightability curve of pdist pushes towards a NE with increasing numbers of obstacles blocking the view, even along perfectly straight transects; • Extrapolating measured dung density to map area on Mount Kenya resulted in an underestimate of c. 13%. An unstratified correction of map area to ground area for Montane areas would be biased because of the strong tendency for elephants to avoid steeply sloping areas. [ABSTRACT FROM AUTHOR]

In this paper, the influence of climate variability and change on the environment was studied over southern Africa using ground-based and remotely sensed data. A time series analysis of rainfall and temperature anomalies indicated that there was a high rainfall and temperature variability in the region. The influence of global teleconnections on rainfall patterns over southern Africa showed that in some areas there was a spatial variation in their strength, increasing from west to east. Maps of NDVI, from 1982 to 2004, showed that changes in vegetation cover were more apparent during the dry season than during the wet season. The study also revealed that climate variability and change are linked to decreasing rainfall and hence, decreasing regional water resources and biodiversity and increasing environmental degradation. With the regional population expected increase, this depletion of resources poses the greatest regional environmental challenge to humankind. [ABSTRACT FROM AUTHOR]

Frequent alteration in land cover often leads to decreased stability of ecosystems which can also increase the vulnerability of rural communities to externalities of environmental change. This study carried out in parts of the coast of southwestern Nigeria utilized topographic base maps and two-time Landsat TM imageries to assess the trend in land cover changes and ecosystems degradation for the three time periods 1965, 1986 and 2001. Remote sensing, geographic information systems and landscape pattern analysis were employed for data processing and analysis. The focus of the analysis was on land cover change, land degradation, and changes in landscape pattern resulting from interplay of natural and anthropogenic drivers. The results show increased trend in human-induced land cover change with concomitant severe negative impacts on ecosystems and livelihoods. About 98,000ha (30% of the area) was seriously degraded as at 2001. About 33,000ha (10%) was under permanent saline water inundation with about 21 communities already dislocated. Loss of fragile ecosystems including marshland (from 7.7% in 1965 to 1% in 2001) and mangrove (from 14.6% in 1965 to 3.1% in 2001) was intense, while over 300 ponds/small lakes which are important for the local fishing economy have disappeared. About eighteen communities were also dislocated by erosion in a section around the southeastern parts of the coastline. Landscape metrics generated, suggested increased ecosystems perturbation and landscape fragmentation. The paper also discussed the implications of these rapid changes for ecosystems stability, food security and sustainable rural livelihoods in the area. [ABSTRACT FROM AUTHOR]

This paper discusses the ecological gradient as an organizing framework to assist understanding the complex interactions between societal and ecological processes underlying land-use change in East Africa. Detailed case studies on the gradients of the slopes of Mt Kilimanjaro, Kenya show how land-use change is responsive to the dynamics of both local and external driving forces. The study has shown that the distinct ecological conditions at the extremities of gradients are associated with specific land uses which may be different within livelihood systems such as for wet and dry season grazing. Access to water for cultivation, domestic use, livestock and wildlife is critical in determining the nature and distribution of livelihood systems. Land-use systems interact across the different ecological zones of the gradients characterized by vigorous spatial, cultural and economic interactions. Sometime conflicts occur between or within land-use/livelihood systems. There is strong evidence that the areas of higher economic potential remain advantaged compared with areas lower on the gradient. The ecological characteristics have been found to influence human activities and distribution. Interactions between societies are important in terms of trade, social relations and access to resources. [ABSTRACT FROM AUTHOR]

To offer an increased understanding of the spatial patterns, temporal, social and physical predictors of the conversion and transformations of land use in Lake Victoria basin, an assessment of proximate and underlying forces is presented. This study discusses key theoretical underpinnings for the manifold linkages existing between selected drivers of land-use changes around the basin and their consequences on human well-being. Using a meta-analytical research design, the paper analyses ecosystems level cases of the causes of land use and cover changes in the basin, to determine any spatio-temporal or institutional patterns and dynamics. A suite of recurrent core variables has been identified to influence land use and cover changes in the basin. The most prominent of these at the underlying category are climatic factors, economic factors, institutions, national and regional policies, population growth and other remote influences. At the proximate level, these factors drive cropland expansion, overgrazing, infrastructure extension and rates of land degradation. These are supported by empirical evidence from the basin. This assessment is crucial for appropriate local and transboundary policy interventions, which have to be fine-tuned to the locale-specific dynamic patterns associated with the inherent ecosystems changes. [ABSTRACT FROM AUTHOR]

The hydrological regime of the Okavango River Basin is the main driver of ecological change in the delta. The delta supports a small-scale fishery which is a source of livelihood for communities within its fringes. The fish resource is particularly important to subsistence fishers, who have limited access to socio-economic opportunities. However, fish availability is subject to ‘concentration and dilution’ effects because of the hydrological regime. As a copying strategy, fishers use a variety of fishing methods to effectively harvest the delta’s fish community across all its trophic levels. This exploitation regime helps to maintain the delta’s species diversity and only reduces fish biomass proportionally across the different trophical levels. Furthermore, fishers have developed different fish-processing techniques to preserve their harvest for low fishing season periods to cope with low food availability. The aim of this paper therefore, was to explore spatio-temporal variations in fish availability and to show how the delta’s subsistence fishers cope with this dynamicity. [ABSTRACT FROM AUTHOR]

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 concern over sustainable livelihoods in African drylands is an issue that has received considerable attention from researchers and policy makers alike. Over the past two decades African rural areas have undergone rapid changes, whereby, rural income diversification has become the most salient feature. With a particular focus on dryland ecosystems, among the major challenges facing communities in these areas is recurrent drought leading to conditions of food insecurity. This paper draws on experience on coping mechanisms for food insecurity from an agro-pastoral community in Mvumi, located in the semiarid areas of central Tanzania. An understanding of livelihoods of people in this area has involved examining how communities have managed to adjust their livelihood in the midst of challenges resulting not only from drought but also from various forces such as socio–economic, political and ecological factors. It has been found out that, despite profound food crisis in this area, people are not always desperate and that there are possibilities for realizing some hidden potentials of dryland resources for livelihood diversification. The issue of sustainable natural resource management in such areas is, however, questionable because of some adverse environmental effects associated with some of the coping mechanisms. [ABSTRACT FROM AUTHOR]

Understanding future ecosystem changes is central to sustainable natural resource management especially when coupled with in-depth understanding of impacts of drivers, such as governance, demographic, economic and climate variations and land use policy. This offers comprehensive information for sustainable ecosystem services provision. A foresight process of systematic and presumptive assessment of future state and ecosystem integrity of Lake Victoria basin, as participatory scenario building technique, is presented. Four scenarios have been illustrated as possible future states of the basin over the next twenty years. Using a scenario building model developed in Ventana Simulation (VENSIM®) platform, the paper presents a scenario methodology for tracking changes in lake basin ecosystem status. Plausible trends in land use change, changes in lake levels and contribution of fisheries are presented. This is part of an initial attempt to setup long-term environmental policy planning strategies for Lake Victoria basin. The assumptions, driving forces, impacts and opportunities under each scenario depict major departure and convergence points for an integrated transboundary diagnosis and analysis of regional issues in the basin as well as strategic action planning for long-term interventions. The findings have been presented in terms of temporal, spatial, biophysical and human well-being dimensions. The attempts in this study can be embedded in a policy framework for basin management priority setting and may guide partnerships for environmental management. [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]

The houbara bustard in the Canary Islands is included into the category ‘Endangered’ on the Spanish Bird Red List according to suspected declines in bird numbers, the loss of previously occupied areas and the suggested endemicity of the taxon. This paper deals with the population size and the distribution pattern of the houbara bustard in Fuerteventura (the largest island occupied by the species in the Canary archipelago, 1730 km2) and analyses its habitat use according to topography, soil, vegetation and human impact variables. We employ distance sampling on 1471 (early spring) and 602 (summer) 500-m transects and measure habitat characteristics within the transects to estimate local densities and population sizes and to test whether the features of the used habitats (as measured in transects where the species was recorded) differed from those available (measured in the whole sample). Topographic and anthropic features are the main determinants of the habitat use of the species, while other descriptors related to vegetation structure and substrate characteristics play a minor role in its habitat preferences. The slope of the terrain is the most important habitat feature constraining the occurrence of the houbara bustard... [ABSTRACT FROM AUTHOR]

To develop an inventory of the present knowledge about soil-borne pests (insects, fungi, nematodes and bacteria) in Uganda, we review in this paper, aspects of their diversity, abundance, distribution in agro-ecosystems control approaches as well as their role in sustainable land management. Knowledge gaps about the soil pests and short falls in human resource capacity are identified as possible factors affecting the development of appropriate management packages for the soil pests. Priority research areas and capacity building needs are suggested. [ABSTRACT FROM AUTHOR]

In this paper, we present results on germination patterns of the seed dispersal system of an endemic Macaronesian plant ( Rubia fruticosa). Seeds from this plant are mainly dispersed by endemic lizards and native warblers; therefore, we included three different treatments: control seeds, seeds extracted from lizards and seeds found in warbler droppings. Seeds from the same pool of every treatment were germinated in two different seasons, one in autumn, coinciding with the arrival of the first rains, and another in spring, coinciding with the arrival of the dry season. A clear differential pattern of germination success was observed between the two seasons. Seeds planted in autumn achieved a higher percentage of germination than those sown in spring in all treatments. The great robustness of these results seems to indicate that germination timing is strongly selected in R. fruticosa and this evolutionary trend probably extends to other vascular plants growing in xeric coastal environments of the Macaronesian islands. [ABSTRACT FROM AUTHOR]

This paper presents the analysis of ten natural regenerated stands of Aucoumea klaineana in native monodominant Aucoumea forest located in the Mayombe rain forest (southern Congo). The mean total density was 0.51 ± 0.15 m−2, the main crop density accounted for 46.12% of the total density, the stocking ranged from 18.02% to 78.10% and the spatial pattern was clumped in all stands. The natural regeneration showed a nearly continuous age distribution. The difference of height between consecutive age-classes indicates a high stability of the seedlings height positions. The upper stratum generally corresponds to the oldest seedling, some new individuals had established during late stages of the regeneration phase. Analysis of the saturated models suggested a different pattern in soils with sand content above and below 80%. The model developed showed a positive correlation between the establishment of successful seedlings and soil preparation, and predicts an increase in the number of main crop seedlings from 0.03 to 1.30 seedlings m−2 when soil preparation is made. On the contrary, grasses cover and mean height of hardwood species were negatively correlated with the density of main crop seedlings. Grasses, hardwood and Cecropiaceae species competition were the main factors that explained total density but only in soils with low sand content. Thus, vegetation-control treatments in regeneration areas are highly recommended. In precommercial thinning, the height position of tree could be used as an important criterion in the selection of the remaining trees. [ABSTRACT FROM AUTHOR]

Inland fishery ecosystems in Africa are characterized by patterns of overexploitation, environmental degradation and exotic species introductions. Ecological complexity and diversity of aquatic habitats dictate that fishes in general are not evenly distributed in a water body. However, fisheries management regimes tend to ignore this basic principle, assume generalized conditions in a water body, and focus more on ‘desired’ objectives such as maximizing catch. The result is to disregard fish habitat boundaries and anthropogenic influences from the catchment that influence fish production. Overexploitation and environmental degradation disrupt sustainable socioeconomic benefits from the fisheries, create uncertainty among investors, but leave some managers calling for more information with the expectation that the fisheries will recover with time. Open access to the fisheries and full control of fishing effort remain challenges for managers. Exotic species introductions and fish farming can increase production, but such interventions require firm commitment to sound ecological principles and strict enforcement of recommended conservation and co-management measures in capture fisheries. The general tendency to downplay fishing effort issues, other ecosystem values and functions or rely on temperate fisheries models until a new cycle of overexploitation emerges, characterizes many management patterns in inland fisheries. Aquaculture is not an option to challenges in capture fisheries management. Aquaculture should be developed to increase fish production but even this practice may have negative environmental impacts depending on practice and scale. Decades of information on Lake Victoria fisheries trends and aquaculture development did not stop the collapse of native fisheries. The successfully introduced Nile perch ( Lates niloticus) has shown signs of overexploitation and aquaculture has again been considered as the option. By reviewing significant trends associated with Nile perch and its feasibility in aquaculture this paper uses Lake Victoria to illustrate ‘special interest management’ targeting selected species of fish rather than the fisheries. [ABSTRACT FROM AUTHOR]

Gynaecological morbidity is one of the most severe conditions under reproductive health. Healthcare providers and planners in Uganda have not taken it seriously among rural communities. This study was carried out mainly to document indigenous knowledge on medicinal plants used by traditional healers in the treatment of some gynaecological morbidity ailments in reproductive healthcare in western Uganda. In addition, the methods of preparation and administration of herbal medicines including the plant parts utilized were established. The research methods used included informal conversations, semi-structured interviews and discussions, and field excursions. The documented conditions under gynaecological morbidity discussed in this paper include excessive-bleeding (hypermenorrhea), painful menstruation (dysmenorrhoea), irregular menstruation and prolapsed uterus. Fifty-two medicinal plants have been documented as being used in the treatment of these ailments and conditions. Leaves are the most commonly harvested plant parts and the most common growth forms harvested are the herbs 51.9%, followed by trees 25% and shrubs 17.3%. Over 50% of these herbal remedies are harvested from the wild ecosystems. The main methods of herbal remedies preparation were boiling, squeezing and pounding and the medicines are administered orally. The nutritional status of individuals plays a vital role in the well-being and in fighting diseases as some medicinal plants are used as foodstuffs like Lycopersicon esculentum Mill., Mangifera indica L., Carica papaya L., Cucurbita pepo L., Physalis minima L., Rumex abyssinicus Jacq., Daucus carota L., Zingiber officinale Roscoe and Ananas comosus (L.) Merr. [ABSTRACT FROM AUTHOR]

The eastern arc mountains (EAMs) are a chain of isolated mountains (534,000 ha) in Kenya and Tanzania surrounded by arid woodlands and influenced by the Indian Ocean. In 1900 there was three times the amount of forest cover there is today. Much of the original forests have been converted into agricultural crops. These mountains are recognized as a globally important ‘hot spot’ by World Wide Fund for Nature (WWF) and World Conservation of Union (IUCN) for forest biodiversity and are major national, regional and local sources of hydropower, water and wide array of forest-based benefits and agricultural production. In February 2000 we began a 3-year evaluation of forest health, land-use change and information sharing in the EAMs. Permanent sample plots were used to evaluate forest health. This paper summarizes the baseline data from eighteen permanent sample plots in the east Usambara's and nine in Ulugurus. The eastern arc web site ( ) was established, continues to expand and contains some detailed information on the project. Information gathered will assist land managers, planners, policy makers, interested communities (villages) and individuals in decision-making. These data can also provide an early warning system of stresses on forest catchments. [ABSTRACT FROM AUTHOR]

In this paper, a model is set up to determine the size of the wildlife population compatible with the extraction of the maximum output by rural people from natural resources. It is found that when the size of human population increases, to obtain the maximum output of food, the size of wildlife population decreases if the human population is growing faster than or at the same rate as that of the wildlife population; whereas the size of the wildlife population increases if the human population is growing slower than that of the wildlife. Furthermore, in the event that the increase in the size of the wildlife population is unable to reach the level compatible with the extraction of the maximum output of food, the improvement of the wildlife habitat and supplementing rural people's income with the proceeds of tourism are proposed as policies to maintain a balance between the preservation of the wildlife habitat and the use of natural resources by rural people. [ABSTRACT FROM AUTHOR]

In this paper, we present a new method for estimating elephant densities by counting elephant wells and dung boli within dry seasonal flooding rivers. A combination of aerial and ground counts of elephant wells and dung boli in the Ewaso Ngiro River were related to elephant numbers, obtained from an on-going monitoring program of individually identified elephants in Samburu and Buffalo Spring National Reserves, Kenya. The total number of elephant observations was highly correlated with both densities of wells and dung boli at a spatial resolution of 4-km river-section. This indicates that both wells and droppings can be used for estimating relative densities at such spatial resolution. The method can be used as a quick and reliable way of estimating relative elephant densities in semiarid regions but is sensitive to differences in the time when different parts of the river dry out and will be unreliable in areas with secondary un-censused water sources. A short 4-week period between the river dry out and the count is recommended, because of an error induced by a level of well reuse and the difficulties in counting areas of high well densities from the air. [ABSTRACT FROM AUTHOR]

This paper examines the ecological threat of tobacco farming in Urambo District, the leading producer of flue-cured tobacco in Tanzania with other major producers being Tabora, Iringa and Chunya Districts. Structured interviews were conducted in four villages while 39 Modified-Whittacker plots were laid in tobacco fallow lands for inventory of woody species to ascertain ecological performance and the impact of tobacco on species diversity, richness and standing stock functions. There was higher than expected species richness with a total of 115 tree and shrub species identified. Tobacco farming showed no significant negative effect on the floristic composition and stem density. However, the significantly reduced biomass and change in vegetation structure illustrate the potential loss in ecological function of the woodlands. Land clearing for tobacco planting account to an annual deforestation of 3.5% while on average a farmer requires 23 m3 of stacked wood only for curing per season which adds another 3% of deforestation. Shifting cultivation is no longer sustainable given the shortened fallow periods of 4 years. Improved barn structures, alternative sources of fuel like coal, tree planting, mixed cropping and cash crops that are environment friendly are recommended for ecological restoration. [ABSTRACT FROM AUTHOR]

Fragmentation of tropical forest alters community composition as a result of changes in forest shape. This paper uses 22 hypotheses to test the effect of fragment shape on tree species composition in Ghana, West Africa, within biological categories of regeneration guild, rarity, phenology and dispersal. For both regenerating and mature trees, relationships between species composition and the shape of forest fragments were complex; almost half were significant but many failed to support the established hypotheses. Irregular shaped fragments had high proportions of regenerating, light-demanding pioneers and mature, animal-dispersed species. Species common to Ghana formed the foundation of communities in fragments of all shapes. Investigation at the landscape level indicated broad patterns of species change. Rigorous hypothesis testing is needed, following extensive demographic work on the ground, before population dynamics within tropical forest fragments can be comprehended fully and applied to conservation management. [ABSTRACT FROM AUTHOR]

In this paper we provide life history characteristics for an introduced marbled lungfish (Protopterus aethiopicus)population in Lake Baringo, Kenya, including their length–weight relationship, body condition, fecundity, sex ratio, reproduction and food. These data are compared with those of other populations. Samples were obtained from the commercial fishery between January and October 2001. The lungfish exhibited positive allometric growth, with the length–weight relationship described by the equation: logW = −6.41 + 3.52 logTL. The mean relative condition factor was close to unity, did not vary much between months and was not significantly different between sexes. The overall sex ratio was skewed in favour of females. The size of fish at first maturity was 70–76 cm total length (TL) for females and 82–88 cm TL for males. Fish in maturity stages III–IV occurred in all monthly samples suggesting year round spawning. The marbled lungfish in Lake Baringo is largely piscivorous and its impact on other fishes certainly warrants further research. [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]

This paper reports on the phenological patterns of figs in Budongo Forest, Uganda, and how it relates to chimpanzee food availability in different seasons. In addition, we analysed the dung of chimpanzees to understand the composition of fruits in their diet. The aim of our study was to assess Ficus phenology and how it affects chimpanzee diet. Fifteen species of figs were monitored for fruit (syconium) and leaf phenology between June 2000 and 2001. Ficus fruit production varied significantly between and within species, and also with tree trunk and crown diameters. Fig fruit production was asynchronous and individual fig trees produced crops from one to five times in a year. In addition to fruits, chimpanzees fed on young leaves of some Ficus species. Shedding of old Ficus leaves coincided with the dry season, followed by appearance of young leaves. The dry season in Budongo is a period of general fruit scarcity. The combination of fig fruits and young leaves make up the most important food in the diet of chimpanzees. From the chimpanzee dung, more than 78% of seeds comprised fig ‘seeds’ (nutlets) and the rest of the diaspores were from other tree species. Our findings suggest that chimpanzees disperse large number of diaspores in their dung, thereby serving as important agents of natural forest regeneration. [ABSTRACT FROM AUTHOR]

Timed Species Counts (TSCs) have been found to provide useful data for assessing the relative abundances of birds in conservation studies, particularly in species-rich areas, such as many tropical habitats. An index is conventionally based upon the mean TSC from a number of counts. In this paper, we develop a new statistic, λ, which is based upon the assumption that the number of encounters with a species in unit time has a Poisson distribution. Using the same assumptions on detectability that underlie earlier analyses of TSC data, values of λ, unlike the simple mean TSC, are directly proportional to abundance. However, TSC data are affected by detectability, so that comparisons of relative abundance for the same species between similar sites have greater validity than those between different species. Explicit formulae for calculating an estimate of λ and its SE from sample data are described. Although λ can be estimated from either TSC data or the simple proportion of counts in which the species was encountered, for the commonest species a simulation study shows that only data in full TSC form provide accurate estimates. The difference becomes negligible for scarcer species. The use of λ in preference to mean TSC scores is recommended where it is important to compare values of relative abundance. [ABSTRACT FROM AUTHOR]