Leaf gas exchange characteristics, biomass partitioning, and water use efficiencies of two C 4 African grasses under simulated drought

Background Few studies have evaluated the effect of drought on the morpho-physiological characteristics of African C4 grasses. We investigated how drought affects leaf gas exchange characteristics, biomass partitioning, and water use efficiencies of Enteropogon macrostachyus and Cenchrus ciliaris. Methods The grasses were grown in a controlled environment under optimum conditions, that is, 70% of the maximum water-holding capacity (WHC) for the first 40 days. Thereafter, half of the columns were maintained under optimum or drought conditions (30% of maximum WHC) for another 20 days. Results Under optimum conditions, C. ciliaris showed a significantly higher photosynthetic rate, stomatal conductance, and transpiration rate than E. macrostachyus. Drought decreased the photosynthetic rate, stomatal conductance and transpiration rate only in C. ciliaris. The net photosynthetic rate, stomatal conductance, and leaf transpiration of E. macrostachyus did not differ significantly under optimum and drought conditions. E. macrostachyus showed an increase in its water use efficiencies under drought to a greater extent than C. ciliaris. Conclusions Our results demonstrate that C. ciliaris is more sensitive to drought than E. macrostachyus. The decrease in the intercellular CO2 concentration and the increase in stomatal limitation with drought in C. ciliaris and E. macrostachyus suggest that stomatal limitation plays the dominant role in photosynthesis of the studied African C4 grasses

A cluster randomised controlled trial of the community effectiveness of two interventions in rural Malawi to improve health care and to reduce maternal, newborn and infant mortality

<p>Abstract</p> <p>Background</p> <p>The UN Millennium Development Goals call for substantial reductions in maternal and child mortality, to be achieved through reductions in morbidity and mortality during pregnancy, delivery, postpartum and early childhood. The MaiMwana Project aims to test community-based interventions that tackle maternal and child health problems through increasing awareness and local action.</p> <p>Methods/Design</p> <p>This study uses a two-by-two factorial cluster-randomised controlled trial design to test the impact of two interventions. The impact of a community mobilisation intervention run through women's groups, on home care, health care-seeking behaviours and maternal and infant mortality, will be tested. The impact of a volunteer-led infant feeding and care support intervention, on rates of exclusive breastfeeding, uptake of HIV-prevention services and infant mortality, will also be tested. The women's group intervention will employ local female facilitators to guide women's groups through a four-phase cycle of problem identification and prioritisation, strategy identification, implementation and evaluation. Meetings will be held monthly at village level. The infant feeding intervention will select local volunteers to provide advice and support for breastfeeding, birth preparedness, newborn care and immunisation. They will visit pregnant and new mothers in their homes five times during and after pregnancy.</p> <p>The unit of intervention allocation will be clusters of rural villages of 2500-4000 population. 48 clusters have been defined and randomly allocated to either women's groups only, infant feeding support only, both interventions, or no intervention. Study villages are surrounded by 'buffer areas' of non-study villages to reduce contamination between intervention and control areas. Outcome indicators will be measured through a demographic surveillance system. Primary outcomes will be maternal, infant, neonatal and perinatal mortality for the women's group intervention, and exclusive breastfeeding rates and infant mortality for the infant feeding intervention.</p> <p>Structured interviews will be conducted with mothers one-month and six-months after birth to collect detailed quantitative data on care practices and health-care-seeking. Further qualitative, quantitative and economic data will be collected for process and economic evaluations.</p> <p>Trial registration</p> <p>ISRCTN06477126</p

Author Correction: Drivers of seedling establishment success in dryland restoration efforts

1 Pág. Correción errata.In the version of this Article originally published, the surname of author Tina Parkhurst was incorrectly written as Schroeder. This has now been corrected.Peer reviewe

The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/ taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems

The African elephant and food security in Africa: experiences from Baringo District, Kenya

Elephants often impose costs on the people who share their range, including threats to life and the destruction of property. Incidences of conflict between humans and elephants, in particular crop destruction crops are increasing in Africa, undermining efforts to conserve biodiversity and food security. This study analysed the impact of crop raiding by African elephants to food security in Baringo District, Kenya. The study area covering 390 km2 was divided into three blocks Kamailel, Mochongoi and Kimoriot. A total of 120 households, 40 per block, were interviewed and data analysed using Statistical Package for Social Sciences. Our results show that human-elephant conflict (HEC) in the study area had reduced by 15%, 20%, and 29% for 2006, 2007 and 2008. Despite reduction in HEC, crop destruction by elephants influenced both household food security and cash income. About 65.5% of the losses were associated with maize, followed by beans (32.8%) and lastly cabbage (1.7%). Crop damage to households was on average KShs.104,225 per household per annum, equivalent to six months household loss of food while the household cash income was reduced by 11.3%. HEC is common among communities living adjacent to protected areas. This often destabilizes communities and undermines their normal livelihood strategies, thus contributing to increased food insecurity

HIV surveillance based on routine testing data from antenatal clinics in Malawi (2011–2018): measuring and adjusting for bias from imperfect testing coverage

Objective: The use of routinely collected data from prevention of mother-to-child transmission programs (ANC-RT) has been proposed to monitor HIV epidemic trends. This poses several challenges for surveillance, one of them being that women may opt-out of testing and/or test stock-outs may result in inconsistent service availability. In this study, we sought to empirically quantify the relationship between imperfect HIV testing coverage and HIV prevalence among pregnant women from ANC-RT data. Design: We used reports from the ANC Register of all antenatal care (ANC) sites in Malawi (2011–2018), including 49 244 monthly observations, from 764 facilities, totaling 4 375 777 women. Methods: Binomial logistic regression models with facility-level fixed effects and marginal standardization were used to assess the effect of testing coverage on HIV prevalence. Results: Testing coverage increased from 78 to 98% over 2011–2018. We estimated that, had testing coverage been perfect, prevalence would have been 0.4% point lower (95% CI 0.3–0.5%) than the 7.9% observed prevalence, a relative overestimation of 6%. Bias in HIV prevalence was the highest in 2012, when testing coverage was lowest (72%), resulting in a relative overestimation of HIV prevalence of 15% (95% CI 12–17%). Overall, adjustments for imperfect testing coverage led to a subtler decline in HIV prevalence over 2011--2018. Conclusion: Malawi achieved high coverage of routine HIV testing in recent years. Nevertheless, imperfect testing coverage can lead to overestimation of HIV prevalence among pregnant women when coverage is suboptimal. ANC-RT data should be carefully evaluated for changes in testing coverage and completeness when used to monitor epidemic trends

Leaf gas exchange characteristics, biomass partitioning, and water use efficiencies of two C4 African grasses under simulated drought

Background: Few studies have evaluated the effect of drought on the morpho-physiological characteristics of African C4 grasses. We investigated how drought affects leaf gas exchange characteristics, biomass partitioning, and water use efficiencies of Enteropogon macrostachyus and Cenchrus ciliaris. Methods: The grasses were grown in a controlled environment under optimum conditions, that is, 70% of the maximum water-holding capacity (WHC) for the first 40 days. Thereafter, half of the columns were maintained under optimum or drought conditions (30% of maximum WHC) for another 20 days. Results: Under optimum conditions, C. ciliaris showed a significantly higher photosynthetic rate, stomatal conductance, and transpiration rate than E. macrostachyus. Drought decreased the photosynthetic rate, stomatal conductance and transpiration rate only in C. ciliaris. The net photosynthetic rate, stomatal conductance, and leaf transpiration of E. macrostachyus did not differ significantly under optimum and drought conditions. E. macrostachyus showed an increase in its water use efficiencies under drought to a greater extent than C. ciliaris. Conclusions: Our results demonstrate that C. ciliaris is more sensitive to drought than E. macrostachyus. The decrease in the intercellular CO2 concentration and the increase in stomatal limitation with drought in C. ciliaris and E. macrostachyus suggest that stomatal limitation plays the dominant role in photosynthesis of the studied African C4 grasses.ISSN:2097-051XISSN:2770-174

Determinants and rates of land degradation: Application of stationary time-series model to data from a semi-arid environment in Kenya

The causes of land degradation in the African drylands have been shown to vary. Some researchers consider climate to be the major contributor to degradation, with anthropogenic factors playing a minor role. Others reverse the significance of these two factors. A third group attributes land degradation to climate and anthropogenic factors equally. This study was undertaken to establish the factors influencing land degradation in a semi-arid environment in southeastern Kenya and the rate of change in vegetation types for a period of 35 years (1973–2007). The reduction in grassland cover was used as an indicator of land degradation. Causes of land degradation were determined by a multiple regression analysis. A log-linear regression analysis was used to establish the rate of vegetation change. The multiple and log-linear regression analyses showed: (1) woody vegetation, livestock population and cultivated area to be the main contributors of reduction in grassland cover in the area, and (2) an increase in undesirable woody species, livestock population and cultivated area had a significant (P<0.05) negative effect on grassland vegetation. Increased human population, low amounts of rainfall and drought showed no significant negative effect on grassland vegetation cover. In conclusion, human and livestock population growth and increased agricultural land have contributed to intensive crop cultivation and overgrazing in the semi-arid lands. This overuse of the semi-arid rangelands has worsened the deterioration of the natural grassland vegetation

A “win-win” scenario: the use of sustainable land management technologies to improve rural livelihoods and combat desertification in semi-arid lands in Kenya

Dryland ecosystems support over 2 billion people and are major providers of critical ecosystems goods and services globally. However, desertification continues to pose a serious threat to the sustainability of the drylands and livelihoods of communities inhabiting them. The desertification problem is well exemplified in the arid and semi-arid lands (ASALs) in Kenya which cover approximately 80% of the total land area. This study aimed to 1) determine what agropastoralists attribute to be the causes of desertification in a semi-arid land in Kenya, 2) document sustainable land management (SLM) technologies being undertaken to improve livelihoods and combat desertification, and 3) identify the factors that influence the choice of the sustainable land management (SLM) technologies. Results show that agropastoralists inhabiting the semi-arid lands in southeastern Kenya mainly attribute desertification to the recurrent droughts and low amounts of rainfall. Despite the challenges posed by desertification and climate variability, agropastoralists in the study area are using a combination of SLM technologies notably dryland agroforestry using drought tolerant species (indigenous and exotic), grass reseeding using perennial native and drought tolerant grass species (vegetation reestablishment) and in-situ rainwater harvesting to improve livelihoods and by extension combat desertification. Interestingly, the choice and adoption of these SLM technologies is influenced more by the additional benefits the agropastoralists can derive from them. Therefore,it isrationale toconclude that success in dryland restorationand combating desertification lies in programs and technologies that offer a “win-win” scenario to the communities inhabiting the drylands

The choice of grass species to combat desertification in semi-arid Kenyan rangelands is greatly influenced by their forage value for livestock

Livestock production is the main source of livelihood in the arid and semi-arid lands in Africa. However, desertification characterized by vegetation degradation and soil erosion is a major threat to the sustainability of land-based production systems. Native rangeland forage species Cenchrus ciliaris L. (Buffel grass/African foxtail grass), Eragrostis superba Peyr. (Maasai love grass) and Enteropogon macrostachyus (Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass) have been used to combat desertification. The objectives of the study were to identify the best-suited native grass species to combat desertification in a semi-arid environment in Kenya and to identify the preferred grass species among the agropastoralists in the area. Percentage basal cover, plant densities and frequencies of the three grasses in pure stands and mixtures were estimated. Grass species preferences were through household survey and focus group discussion. Results showed a significant difference (P < 0 05) in plant densities and cover estimates: E. macrostachyus was ranked first; C. ciliaris and E. superba were ranked second and third respectively. The agropastoral farmers, however, preferred E. superba followed by C. ciliaris and E. macrostachyus, a reverse trend. These results suggest that the choice of grass species to combat desertification is influenced more by its contribution as a source of forage for livestock than its contribution for rehabilitation purposes