The Development of Wildlife Community Conservancies in Kenya: A Preliminary Review

The significance of biodiversity conservation has transformed from a concern for conservation of endangered species and landscapes into an increasingly diverse yet comprehensive set of conservation, social and economic development goals. Community conservancy, a powerful extension of the PA system, has great potential to support biodiversity conservation, poverty eradication and conflict mitigation. Based on its policy environment and development characteristics, Kenya has implemented community conservation practices, and established over 160 conservancies across the country in the past decades. This paper reviews the development and experiences of community conservancies, discusses how they have been implemented in Kenya, and looks at the management paradigm, efficacy and challenges to help better understand the community conservancy approach. The development trajectory and lessons these conservancies have to offer can contribute to the sustainable utilization of natural resources and the enhancement of community wellbeing in Kenya and other countries alike.     

Mg-Al Sapphirine- and Ca-Al Hibonite-bearing Granulite Xenoliths from the Chyulu Hills Volcanic Field, Kenya

Basanites of the Chyulu Hills (Kenya Rift) contain mafic Mg–Aland Ca–Al granulite xenoliths. Their protoliths are interpretedas troctolitic cumulates; however, the original mineral assemblageswere almost completely transformed by subsolidus reactions.Mg–Al granulites contain the minerals spinel, sapphirine,sillimanite, plagioclase, corundum, clinopyroxene, orthopyroxeneand garnet, whereas Ca–Al granulites are characterizedby hibonite, spinel, sapphirine, mullite, sillimanite, plagioclase,quartz, clinopyroxene, corundum, and garnet. In the Mg–Algranulites, the first generation of orthopyroxene and some spinelmay be of igneous origin. In the Ca–Al granulites, hibonite(and possibly some spinel) are the earliest, possibly igneous,minerals in the crystallization sequence. Most pyroxene, spineland corundum in Mg–Al and Ca–Al granulites formedby subsolidus reactions. The qualitative P–T path derivedfrom metamorphic reactions corresponds to subsolidus cooling,probably accompanied, or followed by, compression. Final equilibrationwas achieved at T 600–740°C and P <8 kbar, inthe stability field of sillimanite. The early coexistence ofcorundum and pyroxenes (± spinel), as well as the associationof sillimanite and sapphirine with clinopyroxene and the presenceof hibonite, makes both types of granulite rare. The Ca–Alhibonite-bearing granulites are unique. Both types enlarge thespectrum of known Ca–Al–Mg-rich granulites worldwide. KEY WORDS: granulite xenoliths; corundum; sapphirine; hibonite; Kenya Rift     

Effect of Integrated Use of Inorganic Fertilizer and Organic Manures on Bacterial Wilt Incidence （BWI） and Tuber Yield in Potato Production Systems on Hill Slopes of Central Kenya

Bacterial wilt (BW) caused by Ralstonia solanacearum is one of the most damaging diseases of potato (Solarium tuberosum L.) in Kenya and worldwide. In Kenya, potato tuber yield losses due to BW infection are estimated at 50 ～ 100%. Low soil fertility is also one of the most important constraints limiting potato production in central Kenya highlands. Farmers tackle this problem through use of inorganic fertilisers and organic manures, both of which amend the soil environment to influence bacterial wilt development. Undecomposed organic manures can also introduce the pathogen into a clean field. Between short rains 1999 and 2000, 10 on-farm extension-researcher-farmer-designed and farmer-managed trials were done at Kianjuki catchment in Embu District. The objective was to use farmers‘ participatory research approach and select the most suitable organic and inorganic fertiliser combination(s) with lowest BWI and acceptable usable tuber yields, and also to demonstrate use of some components of integrated disease management methods in reduction of disease incidence and spread. Seven treatments were proposed, presented to the farmers for discussion and the most relevant four were selected for evaluation. A newly released potato variety ‘Asante‘ was planted during the short rains 1999 and long rains 2000. BWI didn‘t result in significant differences between treatments but the tuber yields were significantly different in short rains of 1999 and 2000. During short rains 2000, both BWI and tuber yields and unusable tubers differed significantly between treatments. The results confirmed that well-decomposed manures or manures from pathogen-free areas can be used in combination with inorganic fertilisers to improve soil fertility and potato tuber yields in smallholder farms without influencing BWI. Use of certified seed tubers in pathogen free field and following recommended field sanitation measures resulted in apparently bacterial wilt free crop. Considering the high cost of inorganic ferfiliser and its negative effects on the environment, reduced usage at half the recommended rates combined with half rates of FYM is feasible option friendly to the farmer, soil and environment. The interviewed farmers also ranked the option as the most appropriate combination for soil fertility improvement for potato production in smallholder farms.     

Modelling changing population distributions: an example of the Kenyan Coast, 1979–2009

ABSTRACT

Large-scale gridded population datasets are usually produced for the year of input census data using a top-down approach and projected backward and forward in time using national growth rates. Such temporal projections do not include any subnational variation in population distribution trends and ignore changes in geographical covariates such as urban land cover changes. Improved predictions of population distribution changes over time require the use of a limited number of covariates that are time-invariant or temporally explicit. Here we make use of recently released multi-temporal high-resolution global settlement layers, historical census data and latest developments in population distribution modelling methods to reconstruct population distribution changes over 30 years across the Kenyan Coast. We explore the methodological challenges associated with the production of gridded population distribution time-series in data-scarce countries and show that trade-offs have to be found between spatial and temporal resolutions when selecting the best modelling approach. Strategies used to fill data gaps may vary according to the local context and the objective of the study. This work will hopefully serve as a benchmark for future developments of population distribution time-series that are increasingly required for population-at-risk estimations and spatial modelling in various fields.     

Targeting of intervention areas to reduce reservoir sedimentation in the Tana catchment (Kenya) using SWAT

Abstract

A measurement campaign was carried out in the Upper Tana basin (Kenya) to quantify soil erosion and reservoir sedimentation rates, including a bathymetric reservoir survey and sediment load sampling during one year. Then, distributed soil erosion modelling was performed to study sediment budgets throughout the basin and to evaluate the potential of upstream erosion control through vegetated contour strips and check dams. Finally, the areas where these measures would be most effective were identified and local stakeholder associations to implement them were prioritized. The influence of the scale of implementation was evaluated by using the model to consider three adoption scenarios. This study illustrates the relevance of distributed erosion models to target erosion control measures when sufficient information on the eroding areas is available from field surveys. Bathymetric surveys were fundamental to validate the long-term model response, while point measurements were valuable to verify the spatial variability of model predictions.

Editor Z.W. Kundzewicz; Associate editor G. Mahé

Citation Hunink, J.E., Niadas, I.A., Antonaropoulos, P., Droogers, P., and de Vente, J., 2013. Targeting of intervention areas to reduce reservoir sedimentation in the Tana catchment (Kenya) using SWAT. Hydrological Sciences Journal, 58 (3), 600–614.     

Holocene palaeohydrology,groundwater and climate change in the lake basins of the Central Kenya Rift

Abstract

The Central Kenya Rift contains small soda lakes such as Nakuru, Elmenteita and Bogoria, freshwater Lake Naivasha, and the partly (spatially) freshwater Lake Baringo. The hydrology of this area is controlled mainly by climate, tectonically controlled morphological and volcanic barriers, faults, and local water-table variations. Much of the area relies on groundwater for human and industrial use, though there are widespread quality issues particularly in relation to fluoride. Despite the huge demand for the resource, little is known about the highly complex groundwater systems; lacking monitoring data, an assessment is developed on the basis of regional geological, hydrogeological and hydrochemical analyses. Significant hydrological changes have taken place in the region over the last 10 000 years as a result of global, regional and local changes, but the impacts on groundwater resources are still largely unknown. The IPCC projects a 10–15% increase of rainfall in the area, but it may not necessarily result in a proportional increase in groundwater recharge. High groundwater recharge periods appear to be anchored on a decadal cycle.     

Concentration of particulate organic nitrogen in the marlborough sounds,New Zealand (note)

Samples of particulate matter were analysed for nitrogen by the micro‐Kjeldahl technique in an attempt to obtain an indication of the food available for mussels. The small amounts of nitrogen available in the samples prevented the detection of seasonal variation by this method. The mean concentration of 11.8 μg‐at of nitrogen per litre obtained from this study compares favourably with data from mussel farming areas in Spain.     

Electrical-hydraulic conductivity model for a weatheredfractured aquifer system of Olbanita,Lower Baringo Basin,Kenya Rift

Groundwater yield in the Kenya Rift is highly unsustainable owing to geological variability.In this study,field hydraulic characterization was performed by using geoelectric approaches.The relations between electrical-hydraulic(eh)conductivities were modeled hypothetically and calibrated empirically.Correlations were based on the stochastic models and field-scale hydraulic parameters were contingent on pore-level parameters.By considering variation in pore-size distributions over eh conduction interval,the relations were scaled-up for use at aquifer-level.Material-level electrical conductivities were determined by using Vertical Electrical Survey and hydraulic conductivities by analyzing aquifer tests of eight boreholes in the Olbanita aquifer located in Kenya rift.VES datasets were inverted by using the computer code IP2Win.The main result is that ln T=0.537(ln Fa)+3.695;the positive gradient indicating eh conduction through pore-surface networks and a proxy of weathered and clayey materials.An inverse(1/F-K)correlation is observed.Hydraulic parameters determined using such approaches may possibly contribute significantly towards sustainable yield management and planning of groundwater resources.     

Assessment of erosion damage in Ndome and Ghazi, Taita Taveta, Kenya: Towards an integrated erosion management approach

Aerial photograph interpretation on erosion trends from 1961 to 1998 showed that by 1998, approximately 17 and 50% of agricultural land in Ndome and Ghazi respectively had been permanently lost due to the combined effect of rill, inter-rill, and gully erosion, and sand deposition. Although abnormally heavy rains received between 1996–98 caused much of the present land damage, the severity of the damage was enhanced by inappropriate and persistent human perturbations in the land-system notably through vegetative degradation and destruction of soil structure through inappropriate tillage practices. With soil organic matter contents of 1.6 and 1.9%, and clay ratios of 10.1 and 10.6 for Ndome and Ghazi, respectively, the areas inherent erodibility was considered as high thus pointing to the need for careful use and management of the soil resource. That farmers appreciated only land quality indicators that were visible to the naked eye and that directly affected their subsistence, revealed a knowledge gap that saw damages from intrinsic processes like rill and inter-rill erosion proceed unnoticed. This paper argues that the spread of erosion damage in rural agro-ecosystems is survival-driven. And as a remedy to this problem, there is need for the diversification of livelihood endeavours to alternative off-farm income sources to reduce pressure on the already fragile land resource. Further, being the ultimate implementers of conservation technologies and by virtue of the multiplicity and inter-relation of rural household needs, adoption of an integrated erosion management approach with food security as paramount presents the most practical entry point for sustainable land management in such rural agro-ecosystems. This revised version was published online in July 2006 with corrections to the Cover Date.