Fish populations and biomass in headwater streams of the Lake Tumba Landscape, DR Congo, 2007–2011

The fish biodiversity in the Congo River and its tributaries is extremely rich but the information on fish communities in the headwaters in terms of catch and biomass estimates is rare. Fishes in the running and stagnant waters in this region are of vital importance as a food resource for local residents. This study aimed to describe the fish community, catch, and biomass in the three headwater streams Bambou, Lebomo, and Bongo in the Lake Tumba Landscape (LTL) of the Democratic Republic of the Congo. Such information is of vital impor- tance as a benchmark to understand the sustainability of the fish population for future generations of residents of the LTL. The field data were collected from 2007 through 2011, including dry and wet seasons. Here we present the results of this systematic, multi-annual study which was the first for fishes in streams of this region. In total, 50 species of 15 families were found in the nutrient-poor brown waters of these streams where high concentrations of humic acids cause a low pH. Among abundant species occurring in all three streams were the cyprinid Enteromius holotaenia (Boulenger, 1904), the mormyrid Marcusenius moorii (Günther, 1867), the alestids Clupeocharax schoutedeni Pellegrin, 1926 and Bryconaethiops boulengeri Pellegrin, 1900, and the clariid Clarias angolensis Steindachner, 1866. Bon- go Stream was distinguished from the others by a rich abundance of Alestopetersius compressus (Poll et Gosse, 1963). The presence of several species at low pH (between 5.0 and 5.5) is new information that lowers the bottom of the pH interval for these species compared to earlier reports. The maximum total length (TL) of some other species was by 5–20 percentage points higher than those reported earlier. The median weight per unit effort (WPUE) in the streams varied between 30 and 115 g per hour during the dry seasons and between 18 and 86 g per hour during the wet seasons. The fish biomass in the streams varied between 0.05 and 0.7 g ⸱ m–2 with a median 0.14 g ⸱ m–2. This relatively low value compared to other tropical headwaters may be a result of the low pH and dark color of these headwaters. The results of the study serve as a reference point to which future monitoring of fish fauna can be compared for sustainable management of the LT

Distribution, Abundance, and Biomass Estimates for Primates within Kahuzi-Biega Lowlands and Adjacent Forest in Eastern DRC

Africa’s tropical forests have been subjected to alarming rates of forest clearing in the last two decades. Baseline data are critical to understanding the impacts of large-scale habitat loss and fragmentation. This report describes the distribution and relative abundance of anthropoid primates in 1994–95 within and adjacent to Kahuzi-Biega National Park lowland sector, eastern Democratic Republic of Congo. This is a region for which few empirical data exists. Density and biomass estimates derived from transect sampling are discussed for both adjacent settlement and remote sampling zones where minimum biomass estimates are 436 kg/km2 and 663 kg/km2, respectively. With the exception of red colobus Procolobus badius in sampling zone KB 4, hunting pressures do not appear to have been excessive. The owl-faced guenon Cercopithecus hamlyni is widely distributed and relatively abundant throughout the survey areas

Forest Elephant Crisis in the Congo Basin

Debate over repealing the ivory trade ban dominates conferences of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Resolving this controversy requires accurate estimates of elephant population trends and rates of illegal killing. Most African savannah elephant populations are well known; however, the status of forest elephants, perhaps a distinct species, in the vast Congo Basin is unclear. We assessed population status and incidence of poaching from line-transect and reconnaissance surveys conducted on foot in sites throughout the Congo Basin. Results indicate that the abundance and range of forest elephants are threatened from poaching that is most intense close to roads. The probability of elephant presence increased with distance to roads, whereas that of human signs declined. At all distances from roads, the probability of elephant occurrence was always higher inside, compared to outside, protected areas, whereas that of humans was always lower. Inside protected areas, forest elephant density was correlated with the size of remote forest core, but not with size of protected area. Forest elephants must be prioritised in elephant management planning at the continental scale

Roadless wilderness area determines forest elephant movements in the Congo Basin

A dramatic expansion of road building is underway in the Congo Basin fuelled by private enterprise, international aid, and government aspirations. Among the great wilderness areas on earth, the Congo Basin is outstanding for its high biodiversity, particularly mobile megafauna including forest elephants (Loxodonta africana cyclotis). The abundance of many mammal species in the Basin increases with distance from roads due to hunting pressure, but the impacts of road proliferation on the movements of individuals are unknown. We investigated the ranging behaviour of forest elephants in relation to roads and roadless wilderness by fitting GPS telemetry collars onto a sample of 28 forest elephants living in six priority conservation areas. We show that the size of roadless wilderness is a strong determinant of home range size in this species. Though our study sites included the largest wilderness areas in central African forests, none of 4 home range metrics we calculated, including core area, tended toward an asymptote with increasing wilderness size, suggesting that uninhibited ranging in forest elephants no longer exists. Furthermore we show that roads outside protected areas which are not protected from hunting are a formidable barrier to movement while roads inside protected areas are not. Only 1 elephant from our sample crossed an unprotected road. During crossings her mean speed increased 14-fold compared to normal movements. Forest elephants are increasingly confined and constrained by roads across the Congo Basin which is reducing effective habitat availability and isolating populations, significantly threatening long term conservation efforts. If the current road development trajectory continues, forest wildernesses and the forest elephants they contain will collapse

Conserving great apes living outside protected areas : the distrubiton of bonobos in the Lake Tumba landscape, Democratic Republic of Congo

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The Bonobo Pan paniscus (Mammalia: Primates: Hominidae) nesting patterns and forest canopy layers in the Lake Tumba forests and Salonga National Park, Democratic Republic of Congo

The description and differentiation of habitat types is a major concern in ecology.  This study examined relationships between Bonobo Pan paniscus nesting patterns and forest structure in the Lake Tumba Swampy Forests. Data on presence of fresh Bonobo nests, canopy cover, canopy structure, tree densities and tree basal areas were collected systematically along 134 transects at 400m and 800m intervals, and the leaf-covered area (LCA) was calculated for each of seven forest types. I observed a significant correlation between bonobo nests and mixed mature forest/closed understory forest type (r=-0.730, df = 21, p &lt;0.05), but not mixed mature forest/open understory, old secondary forest and young secondary forest.  Basal areas of non-nesting trees along transects did not differ significantly from those in sites where bonobos nested.  Higher LCA (55% and 55%) occurred in nesting sites when compared with non-nesting sites (39% and 42%) at elevations 4–8 m and 8–16 m above the soil.  There was greater leaf cover in the understorey at sites where bonobos did not nest, while there was greater leaf cover in the mid-storey at sites where bonobos did nest.  </div

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon¹⁻³. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses⁴⁻⁹. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.Keywords: Ecology, Environmental scienc

Effects of epidemic diseases on the distribution of bonobos.

This study examined how outbreaks and the occurrence of Anthrax, Ebola, Monkeypox and Trypanosomiasis may differentially affect the distribution of bonobos (Pan paniscus). Using a combination of mapping, Jaccard overlapping coefficients and binary regressions, the study determined how each disease correlated with the extent of occurrence of, and the areas occupied by, bonobos. Anthrax has only been reported to occur outside the range of bonobos and so was not considered further. Ebola, Monkeypox and Trypanosomiasis were each reported within the area of occupancy of bonobos. Their respective overlap coefficients were: J = 0.10; Q(α = 0.05) = 2.00 (odds ratios = 0.0001, 95% CI = 0.0057; Z = -19.41, significant) for Ebola; J = 1.00; Q(α = 0.05) = 24.0 (odds ratios = 1.504, 95% CI = 0.5066-2.6122) for Monkeypox; and, J = 0.33; Q(α = 0.05) = 11.5 (Z = 1.14, significant) for Trypanosomiasis. There were significant relationships for the presence and absence of Monkeypox and Trypanosomiasis and the known extent of occurrence of bonobos, based on the equations y = 0.2368Ln(x)+0.8006 (R(2) = 0.9772) and y = -0.2942Ln(x)+0.7155 (R(2) = 0.698), respectively. The positive relationship suggested that bonobos tolerated the presence of Monkeypox. In contrast, the significant negative coefficient suggested that bonobos were absent in areas where Trypanosomiasis is endemic. Our results suggest that large rivers may have prevented Ebola from spreading into the range of bonobos. Meanwhile, Trypanosomiasis has been recorded among humans within the area of occurrence of bonobos, and appears the most important disease in shaping the area of occupancy of bonobos within their overall extent of occupancy

Distribution of bonobos relative to the known occurrence of Ebola within the Democratic Republic of Congo.

<p>Inset shows the known distribution of Ebola across Africa. A = Actual outbreak zone and occurrence points for Ebola, adapted from International Federation of Red Cross and Red Crescent Societies, 2009 (Walsh <i>et al.</i>, 2005). B = Modeled potential zone of Ebola outbreaks across Africa (after Peterson <i>et al.</i>, 2004). Grey shading in the main map represents the extent of occurrence of bonobos.</p