Managing the Mount Kenya environment for people and elephants

Forests contain much global biodiversity, and over 90% of the worlds' poorest people depend on them. Few forests remain in East Africa, and these are vulnerable to further fragmentation from expanding settlement, and to over-exploitation by people and wildlife that become prone to over-crowding through isolation. Kenya contains 26 natural habitat fragments and only 3% of forest cover across five main forest blocks. These blocks form the main water towers in semi-arid Kenya on which people and wildlife, far beyond the protected boundaries, depend. Mount Kenya (MK) is the largest forest block, and the protection of its water catchment function is of national importance (Chapter 2). The five forest blocks in Kenya hold almost one third of the total of 28,806 elephants in Kenya, of which MK was estimated as having the largest highland elephant population with 2,911 (±640) individuals in 2001 (Chapter 3). Elephant estimates in forest are usually derived from dung count surveys, which are prone to bias and accordingly most often classed as C or D, in the range from A (best) to E (worst), in the African Elephant Database (AED). The MK elephant estimate described in this thesis was one of only two dung count estimates that were classed as quality B in the AED of 2002 (Chapter 3). Explanatory models based on the dung count data were integrated with a geographic information system (GIS) to develop the most advanced predictive seasonal distribution maps currently available for elephants in a forested environment (Chapter 4). Furthermore, least-cost elephant travel routes and foraging paths were digitally traced over cost surface images, developed from data on preferred elephant habitats in different seasons, physical barriers such as extreme slopes, and land use barriers such as farmland (Chapter 5). This enabled the location of elephant movements in relation to plantations inside the MK forest, and investigation of the relationship between measured tree damage in plantations and elephant movements (Chapter 5). Two areas where subsequently identified where elephant routes strayed from the forest into adjacent farmland, which was where most elephant crop damage was reported by farmers to Kenya Wildlife Service stations and outposts (Chapter 6). Elephants and people trespassing on each other's habitats is pronounced because MK is surrounded by a ring of small-scale farmers, totalling over 500,000 people living within 5,000m of the MK forest boundary on farms of 1.6ha on average (Chapter 6).Time-series analysis of satellite imagery of 1987,1995, and 2000 illustrated a gradual deterioration of MK land and resources, and results of an aerial survey conducted in 1999 showed high levels of illegal exploitation of land and resources (Chapter 7). However, management responsibility of the MK forest transferred from the Forestry Department to the Kenya Wildlife Service in July 2000, and time-series analysis of satellite images of 2000 and 2002 show regeneration of degraded MK land by 2002 (Chapter 8). Comparison of two aerial surveys conducted in 1999 and 2002, showed a significant reduction of illegal exploitation of forest resources on MK by 2002 (Chapter 8). Sound land use management plans are needed for MK to avoid deterioration of the forest by an over-crowded and confined elephant population, and by surrounding people. These plans need to address problems with longer term solutions, regardless of the short term disadvantages that they may entail (Chapter 9)

Large mammals at forest clearings in the Odzala National Park, Congo

Nous avons exploré 36 clairières incluses dans les forêts du Parc National d'Odzala au Congo. Treize espèces de mammifères y ont été observées, dont les plus fréquentes étaient les éléphants, les buffles, les gorilles, les sitatungas, les bongos, les potamochères et les hylochères. Sur la clairière de Maya Nord, les taux de présence des buffles dans la journée était de 71 %, celle des éléphants de 37 % et celle des gorilles de 34 %. Plus de 100 éléphants ont été dénombrés simultanément, ainsi qu'un groupe de 25 buffles tandis que la présence simultanée de deux groupes de gorilles a été observée à plusieurs reprises et qu'un groupe de 17 sitatungas résidait en permanence sur la clairière. Les différences dans le taux de fréquentation des clairières résultent pro parte de l'influence du braconnage des éléphants qui touche plus fortement les clairières situées à proximité des rivières. Les clairières sont essentiellement visitées par les animaux pour la collecte des sels minéraux trouvés dans l'eau, le sol et les végétaux. Elles jouent sans doute un rôle fondamental dans le maintien des fortes densités de populations observées dans la région notamment pour les éléphants et les gorilles. Elles constituent en outre des sites d'observation remarquables. Elles sont cependant des sites idéaux pour le braconnage. Les clairières les plus riches se trouvant hors des limites du PNO, l'extension de ces limites semble une priorité

Addressing uncertainty in marine resource management; combining community engagement and tracking technology to characterize human behavior

This study was approved by the University of Exeter Ethics committee and the Ministry of Scientific Research and Technological Innovation in Congo (Permit: No. 023/MRSIT/DGRST/DMAST); and supported by funding from the Darwin Initiative (Projects 20-009 and 23-011) and the Wildlife Conservation Society.Small-scale fisheries provide an essential source of food and employment for coastal communities, yet the availability of detailed information on the spatiotemporal distribution of fishing effort to support resource management at a country level is scarce. Here, using a national-scale study in the Republic of Congo, we engaged with fishers from 23 of 28 small-scale fisheries landing sites along the coast to demonstrate how combining community engagement and relatively low cost Global Positioning System (GPS) trackers can rapidly provide fine-scale information on: (1) the behavioral dynamics of the fishers and fleets that operate within this sector; and (2) the location, size and attributes of important fishing grounds upon which communities are dependent. This multi-disciplinary approach should be considered within a global context where uncertainty over the behavior of marine and terrestrial resource-users can lead to management decisions that potentially compromise local livelihoods, conservation, and resource sustainability goals.Publisher PDFPeer reviewe

Quantitative estimates of glacial refugia for chimpanzees (Pan troglodytes) since the Last Interglacial (120,000 BP).

Paleoclimate reconstructions have enhanced our understanding of how past climates have shaped present-day biodiversity. We hypothesize that the geographic extent of Pleistocene forest refugia and suitable habitat fluctuated significantly in time during the late Quaternary for chimpanzees (Pan troglodytes). Using bioclimatic variables representing monthly temperature and precipitation estimates, past human population density data, and an extensive database of georeferenced presence points, we built a model of changing habitat suitability for chimpanzees at fine spatio-temporal scales dating back to the Last Interglacial (120,000 BP). Our models cover a spatial resolution of 0.0467° (approximately 5.19 km2 grid cells) and a temporal resolution of between 1000 and 4000 years. Using our model, we mapped habitat stability over time using three approaches, comparing our modeled stability estimates to existing knowledge of Afrotropical refugia, as well as contemporary patterns of major keystone tropical food resources used by chimpanzees, figs (Moraceae), and palms (Arecacae). Results show habitat stability congruent with known glacial refugia across Africa, suggesting their extents may have been underestimated for chimpanzees, with potentially up to approximately 60,000 km2 of previously unrecognized glacial refugia. The refugia we highlight coincide with higher species richness for figs and palms. Our results provide spatio-temporally explicit insights into the role of refugia across the chimpanzee range, forming the empirical foundation for developing and testing hypotheses about behavioral, ecological, and genetic diversity with additional data. This methodology can be applied to other species and geographic areas when sufficient data are available

Managing the Mount Kenya environment for people and elephants

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Large mammals at forest clearings in the Odzala National Park, Congo

After having been located on maps, 36 forest clearings were explored and the presence of large mammals was recorded in the Northern area of the Parc National d’Odzala, Congo. 13 species of large mammals were observed. Elephants, buffaloes, gorillas, sitatungas, bongos, forest hogs, and giant forest hogs were the most common visitors. At the Maya Nord clearing, the rates of presence of buffaloes, elephants and gorillas were particularly high (71 %, 37 % and 34 % of the observation time respectively) while a group of sitatungas was resident. Differences in the rates of clearing fréquentation was found to result from several factors including the past hunting pressure on elephants. Forest clearings constitute an important food source for large mammals which enter clearings for mineral salts contained in soil, water and herbaceous vegetation. They are of great value to maintain the population densities of mammals as well as to develop ecotourism. However, they are also ideal sites for ivory poaching. The richest clearings we explored are not included within the limits of the park : extending these boundaries is a priority.Nous avons exploré 36 clairières incluses dans les forêts du Parc National d’Odzala au Congo. Treize espèces de mammifères y ont été observées, dont les plus fréquentes étaient les éléphants, les buffles, les gorilles, les sitatungas, les bongos, les potamochères et les hylochères. Sur la clairière de Maya Nord, les taux de présence des buffles dans la journée était de 7 1 %, celle des éléphants de 37 % et celle des gorilles de 34 %. Plus de 100 éléphants ont été dénombrés simultanément, ainsi qu’un groupe de 25 buffles tandis que la présence simultanée de deux groupes de gorilles a été observée à plusieurs reprises et qu’un groupe de 17 sitatungas résidait en permanence sur la clairière. Les différences dans le taux de fréquentation des clairières résultent pro parte de l’influence du braconnage des éléphants qui touche plus fortement les clairières situées à proximité des rivières. Les clairières sont essentiellement visitées par les animaux pour la collecte des sels minéraux trouvés dans l’eau, le sol et les végétaux. Elles jouent sans doute un rôle fondamental dans le maintien des fortes densités de populations observées dans la région notamment pour les éléphants et les gorilles. Elles constituent en outre des sites d’observation remarquables. Elles sont cependant des sites idéaux pour le braconnage. Les clairières les plus riches se trouvant hors des limites du PNO, l’extension de ces limites semble une priorité.Vanleeuwe Hilde, Cajani Simona, Gautier-Hion Annie. Large mammals at forest clearings in the Odzala National Park, Congo. In: Revue d'Écologie (La Terre et La Vie), tome 53, n°2, 1998. pp. 171-180

Devastating Decline of Forest Elephants in Central Africa.

African forest elephants– taxonomically and functionally unique–are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002–2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced

Range-wide indicators of African great ape density distribution

Species distributions are influenced by processes occurring at multiple spatial scales. It is therefore insufficient to model species distribution at a single geographic scale, as this does not provide the necessary understanding of determining factors. Instead, multiple approaches are needed, each differing in spatial extent, grain, and research objective. Here, we present the first attempt to model continent-wide great ape density distribution. We used site-level estimates of African great ape abundance to (1) identify socioeconomic and environmental factors that drive densities at the continental scale, and (2) predict range-wide great ape density. We collated great ape abundance estimates from 156 sites and defined 134 pseudo-absence sites to represent additional absence locations. The latter were based on locations of unsuitable environmental conditions for great apes, and on existing literature. We compiled seven socioeconomic and environmental covariate layers and fitted a generalized linear model to investigate their influence on great ape abundance. We used an Akaike-weighted average of full and subset models to predict the range-wide density distribution of African great apes for the year 2015. Great ape densities were lowest where there were high Human Footprint and Gross Domestic Product values; the highest predicted densities were in Central Africa, and the lowest in West Africa. Only 10.7% of the total predicted population was found in the International Union for Conservation of Nature Category I and II protected areas. For 16 out of 20 countries, our estimated abundances were largely in line with those from previous studies. For four countries, Central African Republic, Democratic Republic of the Congo, Liberia, and South Sudan, the estimated populations were excessively high. We propose further improvements to the model to overcome survey and predictor data limitations, which would enable a temporally dynamic approach for monitoring great apes across their range based on key indicators

Encounter rate of elephant dung per kilometre.

<p>Results are shown for the 80 survey sites in Central Africa included in this study. Grey shading represents forest cover.</p

Estimated conditional dependence of elephant dung density for top-ranked multi-variable models including hunter sign.

<p>Results are shown for the top-ranked model with variables: (A) hunter sign*, (B) survey year*, (C) proximity to roads∧, (D) human population density***, (E) corruption*** (higher values = less corrupt) and presence/absence of guards***. Also shown is (F) the Human Influence Index (HII) for the model with proximity to road and human population density variables replaced by the HII, i.e. one of the top-ranking models with variables: hunter sign**, survey year*, HII*, corruption***, and presence/absence of guards***. P-value significance codes are: ‘***’<0.001, ‘**’<0.01, ‘*’<0.05, and ‘∧’<0.1. Plot components are: Estimates on the scale of the linear predictor (solid lines) with the y-axis scale for each variable selected to optimally display the results, confidence intervals (dashed lines), and explanatory variable values of observations with a focus on the core 95% of values for hunter sign, proximity to road and human population density (rug plot - short vertical bars along each x-axis showing the x value for each site).</p