Papyrus Swamps Research Articles

Birds of an Extensive Papyrus Swamp in Uganda and Their Conservation

The delta of the Nile as it enters Lake Albert is part of a Ramsar site and supports 35 km2 of papyrus swamp through which run channels of the river. For 12 months in 2017-2018, we made monthly bird counts, each of ten minutes, at 20 points along swamp edges. Overall, 143 species were recorded, of which 13 were particularly common in the papyrus, and a similar number along the channels. Of seven papyrus-restricted species observed, three are globally red-listed notably papyrus gonolek and shoebill. Most species are resident, but white-winged terns and several hirundine species were seasonally common. Our baseline counts should be repeated in future years as well as recording potential threats—climate change, oil and gas operations and other human activities. Most, but not all, of the Ramsar site is within Murchison Falls National Park, which is well-protected; if possible, the protection should be extended to the whole site.

Plankton Diversity in Tropical Wetlands Under Different Hydrological Conditions (Lake Tana, Ethiopia)

Plankton is an integral part of wetland biodiversity and plays a vital role in the functioning of wetlands. Diversity patterns of plankton in wetlands and factors structuring its community composition are poorly understood, albeit important for identifying areas for restoration and conservation. Here we investigate patterns in local and regional plankton richness and taxonomic and functional community composition in riverine papyrus swamps, river mouth wetlands, and lacustrine wetlands in the Lake Tana sub-basin, Ethiopia. Data on phytoplankton, zooplankton, and environmental variables were collected from 12 wetlands during the dry and wet seasons of 2018. Redundancy analysis, and linear mixed effect models, were used to investigate differences in local environmental conditions and variation in plankton community richness and composition between wetland types. We also assessed the ecological uniqueness of the plankton community by calculating the contribution of a single wetland: local contributions to overall beta diversity (LCBD) and contributions of individual species (SCBD) to overall beta diversity (BDTotal). Beta regression models were used to investigate the relationships of LCBD and SCBD to environmental variables, wetland, and taxa characteristics. A total of 85 phytoplankton taxa, distributed among 18 Reynolds functional groups, and 57 zooplankton taxa were observed over the entire set of samples. Local plankton taxon richness was significantly higher in riverine papyrus swamps (mean taxa of 30 phytoplankton and 21 zooplankton) compared to river mouth wetlands (mean taxa of 27 phytoplankton and 13 zooplankton). Several local environmental variables and the composition of the plankton community differed significantly between the three wetland types. The highest phytoplankton ecological uniqueness (LCBD) was detected in lacustrine wetlands, whereas the riverine papyrus swamps had the highest zooplankton ecological uniqueness. Based on our analyses, we recommend protecting the wetlands with high LCBD values and stress the importance of various wetland types for preserving the diverse plankton communities of Lake Tana wetlands.

Designing effective protected area networks for multiple species

Protected area networks seek to ensure the persistence of multiple species, but their area and extent are limited by available land and conservation resources. Prioritising sites based on their quality, quantity, size, or connectivity is often proposed; potentially using the occupancy and metapopulation dynamics of individual threatened species as surrogates for network effectiveness. However, the extent to which the dynamics of species with overlapping habitat requirements differ, and the implications of this for the optimal network designs for multiple species, are rarely tested. We parameterise metapopulation models for 5 papyrus-specialist birds occupying a network of papyrus swamp in Uganda, each of which possess subtly different ecological characteristics and habitat preferences. We estimate how each responds to different strategies based on prioritising patch size, number, quality and connectivity. The optimal approach differed depending on the metapopulation structure and characteristics of each species. The rank order of strategies also varied with the overall wetland area available and the desired persistence threshold. For individual species, prioritising habitat quality achieved the highest levels of persistence and population size for an equivalent amount of land area conserved. However, connected patches showed greatest overlap across species, thus the most effective strategy to conserve multiple species in the same network prioritised habitat connectivity. This emphasises the importance of individual species' characteristics using the same habitat networks in conservation planning, and demonstrates the utility of prioritising protected sites based on the spatial connectivity of habitat patches, when aiming to conserve multiple species with differing or uncertain habitat requirements.

Clonal growth strategy, diversity and structure: A spatiotemporal response to sedimentation in tropical Cyperus papyrus swamps.

Land degradation and soil erosion in the upper catchments of tropical lakes fringed by papyrus vegetation can result in a sediment load gradient from land to lakeward. Understanding the dynamics of clonal modules (ramets and genets) and growth strategies of plants on such a gradient in both space and time is critical for exploring a species adaptation and processes regulating population structure and differentiation. We assessed the spatial and temporal dynamics in clonal growth, diversity, and structure of an emergent macrophyte, Cyperus papyrus (papyrus), in response to two contrasting sedimentation regimes by combining morphological traits and genotype data using 20 microsatellite markers. A total of 636 ramets from six permanent plots (18 x 30 m) in three Ethiopian papyrus swamps, each with discrete sedimentation regimes (high vs. low) were sampled for two years. We found that ramets under the high sedimentation regime (HSR) were significantly clumped and denser than the sparse and spreading ramets under the low sedimentation regime (LSR). The HSR resulted in significantly different ramets with short culm height and girth diameter as compared to the LSR. These results indicated that C. papyrus ameliorates the effect of sedimentation by shifting clonal growth strategy from guerrilla (in LSR) to phalanx (in HSR). Clonal richness, size, dominance, and clonal subrange differed significantly between sediment regimes and studied time periods. Each swamp under HSR revealed a significantly high clonal richness (R = 0.80) as compared to the LSR (R = 0.48). Such discrepancy in clonal richness reflected the occurrence of initial and repeated seedling recruitment strategies as a response to different sedimentation regimes. Overall, our spatial and short-term temporal observations highlighted that HSR enhances clonal richness and decreases clonal subrange owing to repeated seedling recruitment and genets turnover.

Isotropic and anisotropic processes influence fine-scale spatial genetic structure of a keystone tropical plant.

Limited seed or pollen dispersal enhances spatial genetic relatedness between individuals (fine-scale spatial genetic structure, FSGS), which usually decreases as a function of physical distance. However, such isotropic pattern of FSGS may not always occur when spatially asymmetric processes, for instance, wind direction during dispersal, are considered in wind-pollinated and -dispersed plants. This study assessed the pattern of FSGS in the keystone tropical wetland plant Cyperus papyrus (papyrus) as a function of these isotropic and anisotropic processes. We tested the hypothesis that the FSGS would be influenced by predominant wind direction during pollen and seed dispersal, as well as by the physical distance between individuals. We genotyped a total of 510 adults and 407 juveniles from three papyrus swamps (Ethiopia) using 15 microsatellite markers. In addition, the contemporary directional dispersal by wind was evaluated by seed release-recapture experiments and complemented with parentage analysis. Adults and juveniles differed in the strength of isotropic FSGS ranging from 0.09 to 0.13 and 0.12 to 0.16, respectively, and this suggests variation in dispersal distance. Anisotropic FSGS was found to be a function of asymmetric wind direction during dispersal/pollination that varied between sites. Historical gene dispersal distance was astoundingly low (<4 m), possibly due to localized seed rain. According to our contemporary dispersal estimates, mean pollen dispersal distances were longer than those of seed dispersal (101 and <55 m, respectively). More than two-thirds of seeds and half of pollen grains were locally dispersed (≤80 m). The difference in historical and contemporary dispersal distance probably resulted from the asymmetric wind direction due to change in vegetation cover in the surrounding matrix. We further concluded that, in addition to wind direction, post-dispersal processes could influence gene dispersal distance inferred from the FSGS.

Mapping the Dabus Wetlands, Ethiopia, Using Random Forest Classification of Landsat, PALSAR and Topographic Data

The Dabus Wetland complex in the highlands of Ethiopia is within the headwaters of the Nile Basin and is home to significant ecological communities and rare or endangered species. Its many interrelated wetland types undergo seasonal and longer-term changes due to weather and climate variations as well as anthropogenic land use such as grazing and burning. Mapping and monitoring of these wetlands has not been previously undertaken due primarily to their relative isolation and lack of resources. This study investigated the potential of remote sensing based classification for mapping the primary vegetation groups in the Dabus Wetlands using a combination of dry and wet season data, including optical (Landsat spectral bands and derived vegetation and wetness indices), radar (ALOS PALSAR L-band backscatter), and elevation (SRTM derived DEM and other terrain metrics) as inputs to the non-parametric Random Forest (RF) classifier. Eight wetland types and three terrestrial/upland classes were mapped using field samples of observed plant community composition and structure groupings as reference information. Various tests to compare results using different RF input parameters and data types were conducted. A combination of multispectral optical, radar and topographic variables provided the best overall classification accuracy, 94.4% and 92.9% for the dry and wet season, respectively. Spectral and topographic data (radar data excluded) performed nearly as well, while accuracies using only radar and topographic data were 82–89%. Relatively homogeneous classes such as Papyrus Swamps, Forested Wetland, and Wet Meadow yielded the highest accuracies while spatially complex classes such as Emergent Marsh were more difficult to accurately classify. The methods and results presented in this paper can serve as a basis for development of long-term mapping and monitoring of these and other non-forested wetlands in Ethiopia and other similar environmental settings.

Subsistence use of papyrus is compatible with wetland bird conservation

Conservationists have historically advocated measures that limit human disturbance. Nevertheless, natural disturbances are important components of many ecosystems and their associated species are often adapted to such regimes. In consequence, conservation managers frequently simulate natural disturbance, particularly in temperate forest systems. This practice is less widespread and seldom studied in tropical regions, where biodiversity conservation and human activities are often thought to conflict. However, many tropical systems have been subject to natural and anthropogenic disturbance over evolutionary timescales, and disturbance may therefore benefit the species they host. Determining whether this is true is especially important in tropical wetlands, where human activities are essential for sustaining local livelihoods. Here we investigate the impacts of disturbance from human resource use on habitat–specialist bird species endemic to papyrus swamps in East and Central Africa. Bird densities were estimated using point counts and related to levels of human activity using physical characteristics of wetland vegetation as a proxy for disturbance. All species were tolerant to some degree of disturbance, with particular species occurring at highest density in intensely disturbed habitat. Species were generally more tolerant to disturbance in larger swamps. Our results suggest that low-intensity use of papyrus wetlands by people is compatible with the conservation of specialist bird species, and highlight the potential benefits of traditional human activities to conserve biodiversity in the tropics.

Impact of papyrus wetland encroachment on spatial and temporal variabilities of stream flow and sediment export from wet tropical catchments

During the past decades, land use change in the Lake Victoria basin has significantly increased the sediment fluxes to the lake. These sediments as well as their associated nutrients and pollutants affect the food and water security of millions of people in one of Africa's most densely populated regions. Adequate catchment management strategies, based on a thorough understanding of the factors controlling runoff and sediment discharge are therefore crucial. Nonetheless, studies on the magnitude and dynamics of runoff and sediment discharge are very scarce for the Lake Victoria basin and the African Rift region.We therefore conducted runoff discharge and sediment export measurements in the Upper Rwizi, a catchment in Southwest Uganda, which is representative for the Lake Victoria basin. Land use in this catchment is characterized by grazing area on the high plateaus, banana cropping on the slopes and Cyperus papyrus L. wetlands in the valley bottoms. Due to an increasing population pressure, these papyrus wetlands are currently encroached and transformed into pasture and cropland. Seven subcatchments (358km2–2120km2), with different degrees of wetland encroachment, were monitored during the hydrological year June 2009–May 2010.Our results indicate that, due to their strong buffering capacity, papyrus wetlands have a first-order control on runoff and sediment discharge. Subcatchments with intact wetlands have a slower rainfall–runoff response, smaller peak runoff discharges, lower rainfall–runoff ratios and significantly smaller suspended sediment concentrations. This is also reflected in the measured annual area-specific suspended sediment yields (SYs): subcatchments with encroached papyrus swamps have SY values that are about three times larger compared to catchments with intact papyrus vegetation (respectively 106–137tonkm−2y−1 versus 34–37tonkm−2y−1). We therefore argue that protecting and (where possible) rehabilitating these papyrus wetlands should be a corner stone of catchment management strategies in the Lake Victoria basin.

Estimating standing biomass in papyrus (Cyperus papyrus L.) swamp: exploratory of in situ hyperspectral indices and random forest regression

Accurate estimates of papyrus (Cyperus papyrus) biomass are critical for an efficient papyrus swamp monitoring and management system. The objective of this study was to test the utility of random forest (RF) regression and two narrow-band vegetation indices in estimating above-ground biomass (AGB) for complex and densely vegetated swamp canopies. The normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) were calculated from field spectrometry data and fresh AGB was measured in 82 quadrats at three different areas in the iSimangaliso Wetland Park, South Africa. NDVI was calculated from all possible band combinations of the electromagnetic spectrum (350 and 2500 nm), while EVI was calculated from possible band combinations in the blue, red, and near infrared of the spectrum. Backward feature elimination and RF regression were used as variable selection and modelling techniques to predict papyrus AGB. Results showed that the effective portions of electromagnetic spectrum for estimation AGB of papyrus swamp were located within the blue, red, red-edge, and near-infrared regions. The three best selected EVIs were computed from bands located at (i) 445, 682, and 829 nm, (ii) 497, 676, and 1091 nm, and (iii) 495, 678, and 1120 nm. These indices produced better predictive accuracies (R2 = 0.90; root mean square error of prediction (RMSEP) = 0.289 kg m−2; 7.99% of the mean) than the best selected NDVIs (R2 = 0.85; RMSEP = 0.343 kgm−2; 9.49% of the mean) that were calculated from bands located at (i) 739 and 829 nm, (ii) 739 and 814 nm, (iii) 744 and 789 nm, and (iv) 734 and 909 nm. The results of the present study demonstrate the utility of narrow-band vegetation indices (EVI and NDVI) and RF regression in estimating papyrus AGB at high density, a previously challenging task with broadband satellite sensors.

Diversity and fine-scale spatial genetic structure of Cyperus papyrus populations in Lake Naivasha (Kenya) using microsatellite markers

Papyrus in tropical swamps regenerate vegetatively and through seeds. The study investigated clonal diversity of Cyperus papyrus bordering Lake Naivasha (Kenya). Three regions within the lake were investigated aiming to detect fine-scaled structure in a lakeward transect, including two sites subject to recent dynamic changes, namely a seedling zone and a harvested zone. Using microsatellites, out of 279 ramets, 271 were genets, with most allelic variation observed at individual level but little at site or region level, resulting in very high gene flow levels. At lake level a PCoA grouped lakeward samples distinctly from the landward sites. Somewhat higher inbreeding levels were observed in landward zones but only the harvested site had all loci significantly deviating from the equilibrium implicating the impact of a 6-monthly harvesting regime. A 1,500 m lakeward transect revealed a spatial genetic structure at short distance whereas a very small isolation-by-distance supported a continuous distribution model. The seedling zone contained the highest allelic diversity and individual seedlings were assigned to the nearest shoreline transect, suggesting localized seed rains. Highly diverse C. papyrus swamps of Lake Naivasha are hypothesized to originate mainly from seedling recruitment at short distances, such mature stands can maintain high clonal diversity.

Papyrus swamp drainage and the conservation status of their avifauna

Papyrus Cyperus papyrus swamps sustain the livelihoods of millions of people, but threats to this habitat have never been quantified formally. Birds are useful indicators of threats that cannot be measured directly. Using satellite imagery classification and habitat associated modelling, we quantify drainage and present International Union for Conservation of Nature (IUCN) Red List assessments for the eight taxa most closely associated with this habitat. We show that, between 1984–1987 and 1999–2001 the areal extent of papyrus declined by 6.7 % from 1,643 to 1,532 km2. Papyrus-specialist avifauna has undergone much greater declines, due in part to fragmentation effects and in part to geographical overlap between areas of highest population densities and areas that have experienced greatest habitat loss. Our assessment does not alter the IUCN Red List status of any full species, but it improves current knowledge of the drivers of their extinction risk. Papyrus gonolek Laniarius mufumbiri should remain at least near threatened, but on the basis of population decline rather than a purported small and decreasing range size, and papyrus yellow warbler Chloropeta gracilirostris should remain vulnerable, but again due to declines rather than on the basis of previous under-estimates of population size. Other species should remain listed as least concern. However, taxonomically, likely specifically, distinct populations of papyrus yellow warbler in Zambia and Kenya are highly threatened and should be listed as endangered and critically endangered respectively. We propose several conservation priorities and discuss means of achieving these in a manner consistent with maintaining the livelihoods of people.

Malaria in East African highlands during the past 30 years: impact of environmental changes

East African highlands are one of the most populated regions in Africa. The population densities in the highlands ranged between 158 persons/km2 in Ethiopia and 410 persons/km2 in Rwanda. According to the United Nations Population Fund, the region has the world's highest population growth rate. These factors are likely behind the high rates of poverty among the populations. As there were no employment opportunities other than agricultural, this demographic pressure of poor populations have included in an extensive unprecedented land use and land cover changes such as modification of bushland, woodland, and grassland on hillsides to farmland and transformation of papyrus swamps in valley bottoms to dairy pastures and cropland and changing of fallows on hillsides from short or seasonal to longer or perennial. Areas harvested for food crops were therefore increased by more than 100% in most of the highlands. The lost of forest areas, mainly due to subsistence agriculture, between 1990 and 2010 ranged between 8000 ha in Rwanda and 2,838,000 ha in Ethiopia. These unmitigated environmental changes in the highlands led to rise temperature and optimizing the spread and survival of malaria vectors and development of malaria parasites. Malaria in highlands was initially governed by low ambient temperature, trend of malaria transmission was therefore increased and several epidemics were observed in late 1980s and early 2000s. Although, malaria is decreasing through intensified interventions since mid 2000s onwards, these environmental changes might expose population in the highlands of east Africa to an increase risk of malaria and its epidemic particularly if the current interventions are not sustained.

Discriminating the papyrus vegetation (Cyperus papyrus L.) and its co-existent species using random forest and hyperspectral data resampled to HYMAP

Techniques for discriminating swamp wetland species are critical for the rapid assessment and proactive management of wetlands. In this study, we tested whether the random forest (RF) algorithm could discriminate between papyrus swamp and its co-existent species (Phragmites australis, Echinochloa pyramidalis and Thelypteris interrupta) using in situ canopy reflectance spectra. Canopy spectral measurements were taken from the species using analytical spectral devices but later resampled to Hyperspectral Mapper (HYMAP) resolution. The RF algorithm and a simple forward variable selection (FVS) technique were used to identify key wavelengths for discriminating papyrus swamp and its co-existence species. The method yielded 10 wavelengths located in the visible and short-wave infrared portions of the electromagnetic spectrum with a lowest out-of-bag (OOB) estimate error rate of 9.5% and .632+ bootstrap error of 8.95%. The use of RF as a classification algorithm resulted in overall accuracy of 90.50% and a kappa value of 0.87, with individual class accuracies ranging from 93.73% to 100%. Additionally, the results from this study indicate that the RF algorithm produces better classification results than conventional classification trees (CTs) when using all HYMAP wavelengths (n = 126) and when using wavelengths selected by the FVS technique.

Integrating local ecological knowledge and management practices of an isolated semi-arid papyrus swamp (Loboi, Kenya) into a wider conservation framework

The current study documented local utilization of Cyperus papyrus L. (papyrus), harvesting patterns, threats, and local management practices among the Endorois community living around Loboi swamp (Kenya). Papyrus is a highly productive freshwater macrophyte that is widely utilized throughout tropical Africa. However, increased human population and poverty, has led to over exploitation and conversion of papyrus wetlands to agricultural fields. Nonetheless, users of papyrus hold important local ecological knowledge (LEK) and practices. We show that Endorois practices on papyrus uses are compatible with the management priorities of the swamp and a wider conservation framework using data obtained from three focus group discussions (FGD), interviews of 34 households and 15 key informants. The study revealed that papyrus support local livelihood notably as a source of income (papyrus mats are sold), cattle fodder, roofing materials (shelter), and cooking fuel. The study further revealed important LEK relating to harvesting patterns, recovery after harvesting and traditional management practices. Correlation and principal component analyses showed that experienced old harvesters (EXPERT) avoided harvesting repeatedly at the same location (REVISIT), thereby allowing recovery of papyrus when compared to younger harvesters (r = 0.63, p < 0.01). However, over 70% of harvesters predicted a decrease in papyrus coverage in the future due to the current diversion of water from the swamp, and frequent droughts, despite the instituted traditional management strategies (e.g. rotational harvesting) to curb overharvesting. The study concluded that the documentation of site-scale papyrus users' profile, LEK, and traditional practices are vital for the conservation and management of Loboi swamp.

A Review of the Relative Merits of Conserving, Using, or Draining Papyrus Swamps

Wetlands are a vital resource, particularly in Africa where livelihoods are closely linked to natural capital. In recent years, extensive drainage has occurred to make way for agriculture. To gain insight into whether drainage is justified, we review the value of African wetlands dominated by Cyperus papyrus in relation to use, conservation and conversion. Evidence suggests that the value derived from low-intensity, multifunctional wetland use far exceeds the value derived from swamp reclamation and generally exceeds that of conservation. At a local level, the main driver of wetland misuse appear to be a breakdown in collaborative management regimes and the main constraint on wetland use, the value of labor and selling-times. Local drivers are linked to regional factors such as the lack of coordinated wetland policies and difficulties in ensuring that legislation is absorbed by all sectors of society. We highlight opportunities for ensuring more effective collaborative management and legislation communication, which capitalize on existing governance structures. In contrast to predictions by Hardin's Tragedy of the Commons model, we argue that effective wetland management is best achieved by preventing privatization and promoting common property management regimes. We also argue that poverty and income inequity are more important drivers of unsustainable resource use than environmental managers commonly acknowledge.

Revising estimates of the Shoebill (Balaeniceps rex) population size in the Bangweulu Swamp, Zambia, through a combination of aerial surveys and habitat suitability modelling

The Shoebill Balaeniceps rex is a threatened bird of inaccessible papyrus swamps in central and eastern Africa, and is thus difficult to census. We conducted an aerial survey of Shoebills in the Bangweulu Swamps of north-eastern Zambia using a microlight aircraft in July 2006, and used strip transect methodology to estimate population size. We then applied maximum entropy modelling to satellite images to produce a quantitative map of the likelihood of habitat being suitable (occupied), based on the location of Shoebill sightings. Population size was then re-estimated based on the extent of potentially suitable habitat, which covered 37% of the swamp. Our most conservative mean population size estimate of 1 296 individuals is 550% higher than previous estimates. We suggest that previous estimates may have been underestimates. Our study provides the first estimate of the extent of potentially suitable habitat and an estimate of the population size of Shoebills for the entire swamp. Our analysis of potential habitat suitability can be used to guide future Shoebill surveys, and our methodology can be applied to other little known and inaccessible sites to improve estimates of population size continent-wide.

SRTM DEM levels over papyrus swamp vegetation – a correction approach

Abstract. The SRTM DEM, a digital elevation model based on the Shuttle Radar Topography Mission of February 2000 is a source of elevation data with nearly worldwide coverage. It has proven its usefulness in various regions but problems persist for densely vegetated areas where, caused by the organic matter and water content of the vegetation, the radar signal is reflected at some level between the vegetation canopy and the ground level. This level varies with different types and densities of vegetation cover and has so far not been assessed for papyrus areas. The paper describes the approach and establishment of a correction factor for a pilot area in the Sudd swamps of southern Sudan based on comparison of SRTM reference levels and ground control points collected during field surveys between 2004 and 2006. Results show a correction factor between the sensed and the real surface of 4.66 m and a average penetration depth of the radar signal into the dense papyrus vegetation of 0.34 m.

Effect Of Seasonal Rainfall And Other Environmental Changes, On Snail Density And Infection Rates With &lt;I&gt;Schistosoma mansoni&lt;/I&gt; Fifteen Years After The Last Snails\' Study In Kigungu, Entebbe, Uganda

The last study on snail population density in relation to rainfall pattern in Kigungu canoe landing and recreational sites on Lake Victoria shore was earlier carried out about fifteen years ago. This study also reviewed the influence of other environmental factors on the snails' infection rate. To reassess the density dynamic of Biomphalaria (B) choanomphala and Biomphalaria (B) pfeifferi, which act as the intermediate host for S. mansoni and Bulinus (B) globosus, and Bulinus (B) tropicus, which act as intermediate host for S. haematobium. Retrospective study. Busy canoe landing sites along Lake Victoria in Kigungu fishing village were selected for the snail sampling. Nine thousand one hundred and ninety four B. choanomphala were collected over the study period. The numbers of B. choanomphala collected in each yearwas 4742 (51.6%) and 4452 (48.4%) in 2004 and 2005 respectively. Of the 4742 B. Choanomphala collected in 2004, 82 (1.7%) shed human cercariae and 329 (6.7%) shed non-human cercariae. Whereas in 2005, out of 4452 B. choanomphala collected 302 (6.85%) shed non-human cercariae and 82 (1.8%) shed human cercariae. Similarly, 4173 B. pfeifferi were also collected in the same period. Out of which 2224 (53.3%) were collected in 2004 and 1949 (46.7%) in 2005. For B. pfeifferi, 42 (1.9%) out of 2224 snails collected in 2004 shed human cercariae and 246 (11.1%) shed non-human cercariae. While in 2005, 33 out of 1949 snails (1.7%) shed human cercariae and 159 (8.2%) shed non-human cercariae. Other snails of medical importance collected included 292 B. globosus and 3094 B. tropicus. None of the Bulinus spp. collected shed any human cercariae but 37 (2.1%) and 30 (2.3%) B. tropicus shed non-human cercariae in 2004 and 2005 respectively. In 2004 and 2005, the area received, 1729mm and 1959mm of rainfall respectively, The mean rainfall during the year was 144.05 mm and 163.3 mm in 2004 and 2005 respectively. There was a negative correlation between rainfalls and snail density dynamic. We have found in this study that in spite of the bush clearing of the papyrus swamps which originally was the major habitats for B. choanomphala, B. pfeifferi and the Bulinus spp the intermediate host for schistosome at all canoe landing sites at Kigungu, these snails are still present. Moreover, that their population density dynamic and infection rate are inversely proportional to the rainfall pattern.

Vegetation dynamics in western Uganda during the last 1000 years: climate change or human induced environmental degradation?

AbstractA multi‐proxy analysis of microfossils from sedimentary records, together with evidence from historical and archaeological data, has provided evidence of vegetation dynamics and human environment interactions in western Uganda for the last 1000 years. Pollen, fungal spores and phytoliths extracted from sediment cores obtained from a papyrus swamp at Munsa archaeological site indicate a relatively wet and forested environment in western Uganda prior to ca 1000 yr bp (cal 977–1159 ad). A subsequent decline in forest vegetation occurred from ca 920 yr bp (cal 1027–1207 ad). However, the deforestation period occurred during a wet period as registered in the River Nile water records, suggesting a human induced deforestation at Munsa rather than reduced precipitation. Increased numbers of herbivores, presumably domesticated cattle, postdeforestation are evidenced by the presence of dung fungal spores and broad accord with the archaeological evidence for initial occupation of the site at Munsa and the establishment of a mixed economy based on crops, cattle and iron working between 1000 and 1200 ad. From ca 200 yr bp (cal 1647–1952 ad), forest recovery occurred at Munsa site and appears to reflect abandonment of the site, as suggested by archaeological evidence, possibly following a period of prolonged drought and famine between 1600 and 1800 ad, as recounted in the oral rich traditions of western Uganda and also reflected by low water levels of River Nile.

Ecohydrological principles to underpin the restoration of Cyperus papyrus at Lake Naivasha, Kenya

Degradation of C. papyrus (papyrus) at Lake Naivasha is the result of a combination of lowered lake levels and destruction by large grazing mammals, buffalo and cattle, followed by several smaller species, in addition to more limited direct human clearance. Restoration of papyrus is considered to be of great importance for the future sustainability of the lake ecosystem. Two different interventions for papyrus (wetland) restoration have been proposed: one located around the delta of the Malewa river, based on ecohydrological principles, the other on land adjacent to the Gilgil river, adopting more of an ecological engineering approach. Both interventions are ecologically feasible. However, the principal limitations of both projects relate to anthropogenic factors and, in this respect, restoration of the Gilgil river is regarded as the more pragmatic of the two proposals at the present time. Future action should facilitate the involvement of local communities in any restoration projects at Lake Naivasha, with particular emphasis placed on the development of economic goods derivable from papyrus swamps.