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Schistosomiasis mansoni is an infectious parasitic disease caused by worms of the genus Schistosoma, and praziquantel (PZQ) is the medication available for the treatment of schistosomiasis. However, the existence of resistant strains reinforces the need to develop new schistosomicidal drugs safely and effectively. Thus, the (±)-licarin A neolignan incorporated into poly-Ɛ-caprolactone (PCL) nanoparticles and not incorporated were evaluated for their in vivo schistosomicidal activity. The (±)-licarin A -loaded poly(ε-caprolactone) nanoparticles and the pure (±)-licarin A showed a reduction in the number of worm eggs present in spleens of mice infected with Schistosoma mansoni. In addition, the (±)-licarin A incorporated in the concentration of 20 mg/kg and 200 mg/kg reduced the number of worms, presenting percentages of 56.3% and 41.7%, respectively.

Arabuko Sokoke Forest (ASF) is the largest area of coastal forest remaining in East Africa and a major Important Bird Area in mainland Kenya. The study analysed data from point count surveys over 15 months in three land use types; primary forest (PF), plantation forest (PL), and farmlands (FM), and compared these to the first comprehensive bird checklist for the forest, as well as recent surveys from other studies. Avifaunal diversity and abundance were compared using multivariate analysis to determine bird responses to different land use characteristics. The primary forest held a distinctive bird community, while the bird communities of farmlands and plantation forest were more similar to each other. Land use had a significant effect on overall avian diversity and abundance. The current forest avifauna was divided into forest specialists (16 species), forest generalists (26 species) and forest visitors (30 species). Seven species of forest specialist and generalists recorded prior to 1980 may no longer occur in the forest. Of 38 specialists and generalists recorded in our point counts, 19 were also recorded on farmland and 28 in plantations. One forest specialist, the Green Barbet, was most encountered outside the forest. Future research should focus on habitat use by these bird species, and the extent of movement by forest birds between the remaining patches of coastal forest. Patterns of habitat use by birds in the area suggest that vegetation heterogeneity and habitat complexity are especially significant in sustaining diverse and abundant bird populations. The management of plantations and farmland will be critical for the conservation of forest generalists and forest visitors.

Background Continuous storage root formation and bulking (CSRFAB) in sweetpotato is an important trait from agronomic and biological perspectives. Information about the molecular mechanisms underlying CSRFAB traits is lacking. Results Here, as a first step toward understanding the genetic basis of CSRFAB in sweetpotato, we performed a genome-wide association study (GWAS) using phenotypic data from four distinct developmental stages and 33,068 single nucleotide polymorphism (SNP) and insertion-deletion (indel) markers. Based on Bonferroni threshold (p-value − 7), we identified 34 unique SNPs that were significantly associated with the complex trait of CSRFAB at 150 days after planting (DAP) and seven unique SNPs associated with discontinuous storage root formation and bulking (DCSRFAB) at 90 DAP. Importantly, most of the loci associated with these identified SNPs were located within genomic regions (using Ipomoea trifida reference genome) previously reported for quantitative trait loci (QTL) controlling similar traits. Based on these trait-associated SNPs, 12 and seven candidate genes were respectively annotated for CSRFAB and DCSRFAB traits. Congruent with the contrasting and inverse relationship between discontinuous and continuous storage root formation and bulking, a DCSRFAB-associated candidate gene regulates redox signaling, involved in auxin-mediated lateral root formation, while CSRFAB is enriched for genes controlling growth and senescence. Conclusion Candidate genes identified in this study have potential roles in cell wall remodeling, plant growth, senescence, stress, root development and redox signaling. These findings provide valuable insights into understanding the functional networks to develop strategies for sweetpotato yield improvement. The markers as well as candidate genes identified in this pioneering research for CSRFAB provide important genomic resources for sweetpotato and other root crops.

Land use change can have profound effects on forest ecology, particularly on the avian community. Arabuko-Sokoke Forest, one of the Important Bird Areas (IBAs) in Kenya, is under threat due...

Drought is a recurring hazard which affects many parts of Kenya. In most countries in Sub-Saharan Africa, agriculture which is predominantly rain-fed is the main stay of the economies is highly prone to the impacts of drought which, whenever it occurs, leads to serious socioeconomic challenges at various levels. The study of drought duration, magnitude and severity have relevance in many areas such as waste load allocations, issuance of pollution discharge permits, location of treatment plants and sanitary landfills, determination of allowable water transfers and withdrawals both within, between and outside the affected areas and determination of minimum downstream release requirements for hydropower water supply, cooling plants and other facilities. Knowledge of the frequency distribution of the drought events is useful as it contributes to the assessment of drought risks which have implications on the long term ecological, economic and social well being of the biological and human communities that make use of water from the various streams in a basin. In this study five frequency distributions were fitted to drought duration and severity as determined from discharge data from representative river gauge stations in the upper Tana Basin of Kenya. The frequency distributions fitted to the two drought events were the Generalized Normal (GN) or 3-parameter Lognormal, Generalized Extreme Value (GEV) or the Extreme Value Type III, Generalized Pareto (GPA), Pearson Type III (P3) and Generalized Logistic (GL). The distributions of best fit for the drought events were identified using the Z value obtained from the average L-moment statistics of a particular candidate distribution and the average L-moment statistics. The Z value for each homogenous region was determined from sample estimates of Lcv , Lcs and Lck that were determined from probability weighted moment estimators and the weighted means of Lcv, Lcs and Lck using records from the river gauging stations representing each hydrologically homogenous region. A frequency distribution of best fit was selected if ׀Z Dis ׀ ≤ 1.64 and the one with the lowest ׀Z Dis ׀ value selected as the distribution

To address the potential of legumes to contribute to improved quality and quantity of natural pastures in the semi-arid rangelands of Kenya, five legume species were introduced and evaluated in a small-plot field experiment over three growing seasons. The investigated species were glycine (Neonotonia wightii), siratro (Macroptilium atropurpureum), dolichos (Lablab purpureus cv. Rongai), velvet bean (Mucuna pruriens) and shrubby stylo (Stylosanthes scabra cv. seca). Treatments included two cutting heights (ground level and 15 cm) and two cutting intervals (at 2 and 4 months). The mean dry matter (DM) yields of glycine and siratro were highest when the legumes were harvested at ground level at 2-month intervals (10·31 and 7·81 t ha−1 year−1 respectively). Mean DM yield of stylo was highest when the legume was harvested at 15 cm after 4 months (3·52 t ha−1 year−1). These three legumes also produced high organic matter through litter fall, which contributed to soil fertility. Evidence from a supporting pot experiment showed effective nodulation and potential for N fixation. These legumes also possessed deep tap roots and withstood heavy defoliation. These three legumes were selected for further integration with grasses in natural pastures. The DM yields of dolichos and velvet bean when harvested at 15 cm after 2 or 4 months were low (2·48 and 1·91 t ha−1 year−1), and these species were considered inappropriate for further investigation.

Human–livestock–wildlife interactions have increased in Kenyan rangelands in recent years, but few attempts have been made to evaluate their impact on the rangeland habitat. This study identified drivers of increased human–livestock–wildlife interactions in the Meru Conservation Area between 1980 and 2000 and their effects on the vegetation community structure. The drivers were habitat fragmentation, decline in pastoral grazing range, loss of wildlife dispersal areas and increase in livestock population density. Agricultural encroachment increased by over 76% in the western zone adjoining Nyambene ranges and the southern Tharaka area, substantially reducing the pastoral grazing range and wildlife dispersal areas. Livestock population increased by 41%, subjecting areas left for pastoral grazing in the northern dispersal area to prolonged heavy grazing that gave woody plant species a competitive edge over herbaceous life-forms. Consequently, open wooded grassland, which was the dominant vegetation community in 1980, decreased by c. 40% as bushland vegetation increased by 42%. A substantial proportion of agro pastoralists were encountered around Kinna and Rapsu, areas that were predominantly occupied by pastoralists three decades ago, indicating a possible shift in land use in order to spread risks associated with habitat alterations. Resume Les interactions hommes-betail-faune sauvage ont augmente dans les pâturages kenyans ces dernieres annees, mais il y a eu peu de tentatives pour evaluer leur impact sur cet habitat. Cette etude identifie quelles ont ete les raisons sous-jacentes de ces interactions dans l’Aire de Conservation de Meru entre 1980 et 2000, et leurs effets sur la structure de la communaute vegetale. Les raisons etaient la fragmentation de l’habitat, le declin de la surface libre pour le pâturage pastoral, la perte d’aire de dispersion pour la faune sauvage et l’augmentation de la densite de population du betail. L’envahissement agricole a augmente de plus de 76% dans la zone ouest touchant les fermes de Nyambene et l’aire sud de Tharaka, reduisant substantiellement l’etendue du pâturage pastoral et les aires de dispersion de la faune sauvage. La population du betail a augmente de 41%, soumettant les etendues laissees au pâturage pastoral dans la region de dispersion nord a un pâturage intensif prolonge qui a donne aux especes vegetales ligneuses un avantage sur les formes herbeuses. Par consequent, la prairie arboree ouverte, qui etait la communaute vegetale dominante dans les annees 1980 a diminue de pres de 40% alors que la vegetation de broussailles a augmente de 42%. Une proportion substantielle d’agropastoralistes se rencontraient autour de Kinlla et de Rapsu, des zones qui etaient principalement occupees par des pasteurs il y a trois decennies, ce qui indique une evolution possible de l’utilisation des sols afin de disperser les risques lies a l’alteration des habitats.

O presente texto busca comprender as raízes sócio-históricas contidas na cultura do trabalho dos pescadores artesanais pernambucanos, a qual liga seu saber-fazer pesqueiro às categorias arte e autonomia. Nesse sentido, o passado torna-se campo fértil para encontrarmos – nos dias de hoje - vários aspectos que repercutem nas “formas de ser” e nas “determinações de existência” pertencentes à organização produtiva da pesca artesanal. Palavras-Chave: Pescadores artesanais, arte, autonomia, cultura do trabalho pesqueira, Pernambuco. This text intends to understand the socio-historical roots in the culture of the artisanal fishermen work from Pernambuco, which connects its fishing know-how to the category of art and autonomy. In that sense, the past becomes a fertile field to find – nowadays – several aspects that impact on “ways to be” and the “determination of existence” belonging to the productive fishing organization. Key words: Fishermen craft, art, autonomy, work culture of fishing, Pernambuco.

Chloris roxburghiana is an important rangeland grass in Kenya. In some areas it has disappeared due to land degradation resulting from overgrazing and drought. Efforts to re-introduce the grass through re-seeding using seeds from research stations have had little success. One possible reason for low establishment is attributed to transplanting spatially separated populations that may represent genetically distinct ecotypes. To test this hypothesis, germplasm diversity within and among four populations of C. roxburghiana from four ecologically distinct sites was analysed using random amplified polymorphic DNA (RAPD) markers. A total of 131 polymorphic markers were identified using nine RAPD primers. There was significant variation among populations, with genetic diversity (H) ranging from 0.134 to 0.206. Analysis of molecular variance (AMOVA) revealed most variance within populations (76%). However, the variation among populations was also significant (24%). The UPGMA of the population frequency indicated ...

These success stories describe how two programs helped families to strengthen their health agricultural livelihoods and food security in Malawi. The programs helped households to grow more food guided farmers toward profitable business practices helped people to form savings groups taught families and young mothers about health and nutrition and increased access to HIV services and social welfare systems.

A research study was conducted in Mashuru Division of Kajiado District, Kenya with the objective of analyzing the types of vegetation degradation, their causes and their influence on rangeland condition and trend. The study was conducted through remote sensing tools, ground truthing, interviews, community workshop and literature. The results of the study showed that excessive use of the woody species by humans for woodfuel, building and fencing materials, medicine and ornamentals had led to the deterioration of the rangeland due to a loss of cover, change in plant composition and biodiversity. On the other hand, overgrazing and ecological succession of the grazing lands had led to further vegetation degradation in form of bush encroachment and thickening. These types of vegetation degradation have had an overall effect of loss of grass cover and hence loss of grazing capacity by livestock, especially cattle. The causes of vegetation decrease or increase over the last 30 years have been due to deforestation (trees and shrubs), bush encroachment and thickening , change in plant species composition and natural calamities such as droughts, wild fires and army worm invasions at various times. The overall results indicated that there has been a downward trend in range condition over the last 30 years which has affected the livestock productivity of the area.

This study was conducted in the northern part of Kenya, in Kakuma division, Turkana district. Kakuma is a semi- arid area under nomadic pastoralism as the main activity. The presence of a refugee camp has attracted many people from within the Turkana community and also the outside community. The study aimed at documenting the effects of emergent land use changes on vegetation resources and the socio-economic environment in Kakuma. Data on vegetation density and cover was collected. Socio-economic data was collected from the local Turkana population and the settlement camp. The data was analysed using SPSS computer package and descriptive statistics. There was a significant difference (P

The Maasai indigenous knowledge of animal diseases is comparable to the conventional knowledge of the modern veterinarian. Their diagnostic skills of livestock diseases is based on indigenous symptoms of diseases, vectors of diseases, season effects and species affected. The pastoralist diagnostic skills appear to be superior to those of agropastoralists. With the advent of modern veterinary medicine, the Maasai ethnoveterinary practice appears to be on the decline. This paper focuses on indigenous knowledge basis for diagnosis, treatment and control of selected examples of livestock diseases. In addition, the impact of modern veterinary medicine on pastoral (Maasai) ethnoveterinary practice will be briefly discussed.

Fifteen yearling goats of similar weight were used to evaluate the potential of Zizyphus spina-christi leaves as a supplement to goats fed on Cynodon dactylon grass. Animals were randomly assigned to five feeding regimes and individually stall-fed for a preliminary period of 14 days, followed by 14 days of feeding to determine dry matter intake and digestibility and a 3-month feeding period to determine body weight changes. The treatments were formulated based on leaf:grass ratios of 0%, 25%, 50%, 75% and 100%. Z. spina-christi leaves had higher crude protein and lower fibre content than C. dactylon grass (P Z. spina-christi foliage is a potential feed supplement in the dry season, as the dry season grasses are deficient in the required nutrients and cannot meet goat requirements. African Journal of Range & Forage Science 2003, 20(3): 265–270

The study was conducted in the Blue-Nile valley of Wogidi district in Ethiopia, where woody vegetation degradation associated with intensive land use activities has become a national concern. It wa...

A study was conducted in the semi-arid Kibwezi division of Kenya to investigate the effect of moisture availability on nitrogen and phosphorus uptake by plants. The study consisted of four treatments i.e. control, grass, legume, and grass/legume mixture. These were replicated on two sites with different soils. On each site, two sets of treatment were set up whereby one was WATER AVAILABILITY ON NITROGEN AND PHOSPHORUS UPTAKE BY RANGE PLANTS 361 given additional water, whereas one remained unwatered. The experiment was conducted during the short and the long rains. CP and P contents were determined for each of the treatments and seasons. The CP content of plants generally decreased as they grew from vegetative to seeding stage. Watering had no significant effect (P

Data on litter production and decomposition in an arid rangeland in Kenya was collected over a two-year period. Litter sampling was carried out at monthly intervals using a rectangular 0.25m-2 quadrat frame. Litter within the quadrats was handpicked and washed with running water to get rid of soil particles, dried, and weighed. Weights were expressed on organic matter basis. Monthly litter production ranged from 31.4g m-2 to 130.0g m-2. Mean monthly yield was 92.5 ± 26g m-2, with a 28% coefficient of variation. There was no significant difference (p>0.01) in litter yield between 1992 and 1993. Rate of decomposition for aboveground material ranged from 0.005g g-1 day-1 to 0.084g g-1 day-1. The mean annual rate of decomposition was 0.026g g-1 day-1. Belowground plant material rates of decomposition spread from 0.009g g-1 day-1 to 0.062g g-1 day-1, with a mean annual rate of 0.041g g-1 day-1. Belowground material consistently decomposed faster than aboveground material. Peaks in both aboveground and belowground material decomposition rates coincided with rainfall peaks. Overall, in this arid environment, litter production and decomposition is pulsed in nature, and trends are closely related to rainfall occurrence. Moisture is thus a limiting factor both to the production and decomposition of litter. Belowground litter plays a significant role in nutrient cycling. Keywords: dead herbage yield; dryland ecosystem; ecosystem function; nutrient cycling African Journal of Range & Forage Science 2001, 18(2&3): 125-129

A study was conducted to determine the nutritional characteristics of selected grass and browse species from “Kenya” rangelands. The identified species were analyzed for their chemical composition ...

Semi-arid rangelands in Kenya are an important source of forage for both domestic and wild animals. However, indigenous perennial grasses notably Cenchrus ciliaris (African foxtail grass), Eragrostis superba (Maasai love grass) and Enteropogon macrostachyus (Bush rye grass) are disappearing at an alarming rate. Efforts to re-introduce them through restoration programs have often yielded little success. This can partly be attributed to failure of topsoil to capture and store scarce water to meet germination and plant growth requirements. A study was undertaken in the semi-arid environment of eastern Kenya to determine the effects of land treatment on morphometric characteristics of E. superba, C. ciliaris and E. macrostachyus. Seed viability of the grasses was estimated by germination tests. Land treatments involved soil ripping using a tractor and hand-clearing. Thirty-five plants were randomly selected per sub-plot and tagged for sampling. Morphometric characteristics of the grass species were measured weekly. Aboveground biomass was estimated by harvesting standing biomass three months after establishment. Seed viability tests showed significant differences (p

This study investigated the role of moisture in the successful rehabilitation of denuded patches in semi-arid lands of Kenya and the primary productivity of three perennial rangelands grasses namely Cenchrus ciliaris (African foxtail), Enteropogon macrostachyus (Bush rye) and Eragrostis superba (Maasai love grass) at three phenological stages (early growth, elongation and reproduction) as pure stands and two-grass mixtures. The grasses were sown on either rainfed (Sites 1 and 2) or simulated rainfall conditions (site 3). Site preparation in all the 3 sites involved mechanical bush clearing, use of fire and creation of micro-catchments using an ox-drawn plough. Soils in site 3 were sandy clay loams and those in sites 1 and 2 were sandy clays. There was total failure in establishment sites 1 and 2 under natural rainfall. Site 3 had good germination and subsequent establishment. These results were attributed to the moisture conditions in the three sites. There was a significant difference (p

Savannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in regulating woody cover, but perceptions differ on which of these are the primary drivers of savanna structure. Here we show, using data from 854 sites across Africa, that maximum woody cover in savannas receiving a mean annual precipitation (MAP) of less than approximately 650 mm is constrained by, and increases linearly with, MAP. These arid and semi-arid savannas may be considered 'stable' systems in which water constrains woody cover and permits grasses to coexist, while fire, herbivory and soil properties interact to reduce woody cover below the MAP-controlled upper bound. Above a MAP of approximately 650 mm, savannas are 'unstable' systems in which MAP is sufficient for woody canopy closure, and disturbances (fire, herbivory) are required for the coexistence of trees and grass. These results provide insights into the nature of African savannas and suggest that future changes in precipitation may considerably affect their distribution and dynamics.

A two-year study was conducted with an overall objective of characterising the structure and function of an arid rangeland in Kenya. A plot measuring 100 x 100m was used for this study. Data on rainfall and temperature were recorded at the plot site whereas data on evaporation rates and relative humidity were obtained from the meteorological office near the study site. Herbaceous aboveground material was sampled at monthly intervals using a rectangular 0.25m2 quadrat frame. Clipped material was separated by species and classified dead or live by physical examination. A 5cm diameter metal soil corer was used to sample belowground plant material, at monthly intervals. The sampled material was washed with running water over 2mm sieves and classified dead or live using the vital staining technique. All weights and calculations were based on organic weight. Total aboveground standing crop ranged from 84.6g m-2 to 295.4g m-2, with a mean of 162.3 60.6g m-2. Mean monthly aboveground standing crop for 1992 and 1993 was 142.8 53.8 and 178.5 63.3g m-2 respectively. The two values were significantly different (p0.01) in the mean belowground dead material yield between 1992 and 1993. In 1992, annual NPP was 439.2g m-2, giving a net primary productivity of 1.22g m-2day-1. Monthly NPP ranged from 17.2g m-2 to 90.1g m-2. In 1993, annual NPP was 944.5g m-2, equivalent to a net primary productivity of 2.62g m-2day-1. Monthly NPP was between 27.4g m-2 and 548.6g m-2. Over the 1992—1993 period, NPP was 1 383.7g m-2, equivalent to a productivity of 1.92g m-2day-1. Trends in monthly NPP closely followed the trend in rainfall. On the whole, herbaceous vegetation production and productivity were episodic in nature and closely linked to rainfall. The high primary productivity puts arid and semi-arid rangelands under sharp focus as CO2 sinks, whose role in the amelioration of greenhouse effect could be more important than is currently appreciated. Keywords: climatic elements; aboveground biomass; belowground biomass; primary productivity African Journal of Range & Forage Science 2001, 18(2&3): 117-124