Grasslands Of Africa Research Articles

Cultures of Fermentation

Cultures of Fermentation

Insights into the diet and feeding behaviour of Red-capped Lark Calandrella cinerea (Aves: Passeriformes: Alaudidae)

Anthropogenic activities have continued to threaten critical habitats of many tropical birds. Few studies, however, have established the habitat requirements, diet and foraging strategies of the threatened species to guide conservation efforts. The Red-capped Lark Calandrella cinerea, which inhabits tropical grasslands in Africa is highly threatened by habitat loss and anthropogenic activities such as burning for pasture regeneration and overgrazing by livestock. Many aspects of the feeding behaviour of this threatened tropical lark are still unknown. We studied the diet and feeding behaviour of the adult Red-capped Lark in its open grassland habitat at Kedong, Naivasha, Kenya from 04 March 2016 to 12 August 2016. Findings revealed that birds predominantly consumed animal nutrients that included insect larvae/caterpillars, grasshoppers, moths/butterflies, ants, and beetles. This was supplemented with plant nutrients (grass seeds) from two grass species, Eragrostis tenuifolia and Harpachne schimperi. Picking and gulping were the most employed food capture and handling techniques respectively. In relation to foraging substrates, grass substrate was most selected for food capture as compared to large mammal dung and soil mounds. Given that tropical grasslands are becoming increasingly threatened biomes, the findings are critical in guiding the management of grassland habitats of birds to ensure their protection from negative impacts as well as deepen understanding on how they adapt to environmental changes.

The conservation costs and economic benefits of using biodiversity offsets to meet international targets for protected area expansion

AbstractAichi Biodiversity Target 11 under the Convention on Biological Diversity sets out to conserve at least 17% of terrestrial area by 2020. However, few countries are on track to meet this target and it is uncertain whether developing countries have allocated sufficient resources to expand their protected areas. Biodiversity offsets could resolve this conservation shortfall if developers who affect biodiversity negatively at one locality are made responsible for its protection elsewhere. Here we simulate the use of biodiversity offsetting to expand protected area coverage in South Africa's grassland biome. South Africa's biodiversity offsets policy has been designed specifically to compensate for the residual loss of biodiversity caused by development, by establishing and managing protected areas within the same ecosystem type. We show that it is possible to meet protected area targets using only offsets, while facilitating economic development. However, doing so could slash the current extent of intact habitat by half. These losses could be reduced considerably should the gains in protected areas through offsetting supplement rather than supplant existing government commitments to protected area expansion. Moreover, supplementing existing government commitments would result in comparatively small reductions in potential economic gains, because the marginal economic benefit of transforming habitat decreases as more intact habitat is lost. Therefore, the intended role of biodiversity offsetting in achieving a country's protected area target should be made explicit to fully understand the associated trade-offs between conservation and economic development.

Wild Herbivore Grazing Enhances Insect Diversity over Livestock Grazing in an African Grassland System.

Southern Africa’s grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild grazed EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic grazing. Furthermore, species composition shows significant differences between the two grazing systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs.

Biomass burning fuel consumption dynamics in the tropics and subtropics assessed from satellite

Abstract. Landscape fires occur on a large scale in (sub)tropical savannas and grasslands, affecting ecosystem dynamics, regional air quality and concentrations of atmospheric trace gasses. Fuel consumption per unit of area burned is an important but poorly constrained parameter in fire emission modelling. We combined satellite-derived burned area with fire radiative power (FRP) data to derive fuel consumption estimates for land cover types with low tree cover in South America, Sub-Saharan Africa, and Australia. We developed a new approach to estimate fuel consumption, based on FRP data from the polar-orbiting Moderate Resolution Imaging Spectroradiometer (MODIS) and the geostationary Spinning Enhanced Visible and Infrared Imager (SEVIRI) in combination with MODIS burned-area estimates. The fuel consumption estimates based on the geostationary and polar-orbiting instruments showed good agreement in terms of spatial patterns. We used field measurements of fuel consumption to constrain our results, but the large variation in fuel consumption in both space and time complicated this comparison and absolute fuel consumption estimates remained more uncertain. Spatial patterns in fuel consumption could be partly explained by vegetation productivity and fire return periods. In South America, most fires occurred in savannas with relatively long fire return periods, resulting in comparatively high fuel consumption as opposed to the more frequently burning savannas in Sub-Saharan Africa. Strikingly, we found the infrequently burning interior of Australia to have higher fuel consumption than the more productive but frequently burning savannas in northern Australia. Vegetation type also played an important role in explaining the distribution of fuel consumption, by affecting both fuel build-up rates and fire return periods. Hummock grasslands, which were responsible for a large share of Australian biomass burning, showed larger fuel build-up rates than equally productive grasslands in Africa, although this effect might have been partially driven by the presence of grazers in Africa or differences in landscape management. Finally, land management in the form of deforestation and agriculture also considerably affected fuel consumption regionally. We conclude that combining FRP and burned-area estimates, calibrated against field measurements, is a promising approach in deriving quantitative estimates of fuel consumption. Satellite-derived fuel consumption estimates may both challenge our current understanding of spatiotemporal fuel consumption dynamics and serve as reference datasets to improve biogeochemical modelling approaches. Future field studies especially designed to validate satellite-based products, or airborne remote sensing, may further improve confidence in the absolute fuel consumption estimates which are quickly becoming the weakest link in fire emission estimates.

Are there consistent grazing indicators in Drylands? Testing plant functional types of various complexity in South Africa's Grassland and Savanna Biomes.

Despite our growing knowledge on plants’ functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa’s grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs). Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses) and two-trait PFTs (e.g. perennial grasses) performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold) had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may also be useful for identifying ecological indicators in other ecosystems.

Stature, body mass, and brain size: A two-million-year odyssey

Physical size has been critical in the evolutionary success of the genus Homo over the past 2.4 million-years. An acceleration in the expansion of savannah grasslands in Africa from 1.6Ma to 1.2Ma witnessed concomitant increases in physical stature (150–170cm), weight (50–70kg), and brain size (750–900cm3). With the onset of 100,000year Middle Pleistocene glacial cycles (“ice ages”) some 780,000years ago, large-bodied Homo groups had reached modern size and had successfully dispersed from equatorial Africa, Central, and Southeast Asia to high-latitude localities in Atlantic Europe and North East Asia. While there is support for incursions of multiple Homo lineages to West Asia and Continental Europe at this time, data does not favour a persistence of Homo erectus beyond ∼400,000years ago in Africa, west and Central Asia, and Europe. Novel Middle Pleistocene Homo forms (780,000–400,000years) may not have been substantially taller (150–170cm) than earlier Homo (1.6Ma–800,000years), yet brain size exceeded 1000cm3 and body mass approached 80kg in some males. Later Pleistocene Homo (400,000–138,000years) were ‘massive’ in their height (160–190cm) and mass (70–90kg) and consistently exceed recent humans. Relative brain size exceeds earlier Homo, yet is substantially lower than in final glacial H. sapiens and Homo neanderthalensis. A final leap in absolute and relative brain size in Homo (300,000–138,000years) occurred independent of any observed increase in body mass and implies a different selective mediator to that operating on brain size increases observed in earlier Homo.

Review of the Genus Andropogon (Poaceae: Andropogoneae) in America Based on Cytogenetic Studies

Andropogon is a pantropical grass genus comprising 100–120 species and found mainly in the grasslands of Africa and the Americas. In the new world the genus is represented by approximately sixty (diploids or hexaploids) species grouped in three sections. The hexaploid condition occurs only in the Americas and the full process of this origin is still uncertain, although cytogenetic analysis coupled with taxonomic evidence have provided strong support for new hypothesis. Stebbins proposed the first hypothesis suggesting that the origin of polyploidy in species of Andropogon in North America resulted from duplication of the genome of some diploid species, and then by intergeneric crosses with species of a related genus. Since then, numerous studies were performed to clarify the evolutionary history of the genus in America. In this paper, we present a review of cytogenetic studies in the American Andropogon species during the last four decades.

Meiotic behavior as a selection tool in the breeding of Brachiaria humidicola (Poaceae)

Brachiaria humidicola is a tropical grass that grows in seasonally swampy grasslands in Africa. In Brazil, two apomictic cultivars (2n = 54) of this species are widely used as pastures in poorly drained soils. The recent discovery of a sexual polyploid accession (2n = 36) in the germplasm collection at the Embrapa Beef Cattle Research Center allowed intraspecific hybridization with the objective of broadening the genetic variability and selection of superior genotypes in this species. Hybridization, however, depends on accessions with the same ploidy level. Cytological analyses of 55 accessions revealed that 19 apomictic accessions also presented 2n = 36 chromosomes. Chromosome pairing in hexavalent association at diakinesis and metaphase I suggested that the basic chromosome number for this species is x = 6. Cytological analysis revealed abnormalities in variable frequencies in the meiosis of these hexaploid (2n = 6x = 36) accessions. The most common were those related to irregular chromosome segregation which led to unbalanced gamete formation, but chromosome stickiness was also recorded. These results clearly demonstrate the value of cytogenetics in the choice of genitors and for superior hybrids to be obtained in the breeding of this species. For that both the ploidy level and the frequency of abnormalities need to be considered, besides other favorable agronomic characteristics.

Meiotic behavior in nonaploid accessions of Brachiaria humidicola (Poaceae) and implications for breeding

Brachiaria humidicola is a grass adapted to seasonally swampy grasslands in Africa; two cultivars, 'common' and Llanero, are widely used in Brazilian pastures. New cultivars are in great demand in order to diversify current production systems to achieve improved quality and yield. Cytological analyses of 55 accessions of this species available from the Embrapa Beef Cattle germplasm collection revealed that 27 are apomictic and have 2n = 54 chromosomes. Chromosome pairing as bi- to nonavalent associations at diakinesis indicated a basic chromosome number in this species of x = 6, as found in other closely related Brachiaria species. Thus, these 27 accessions are nonaploid (2n = 9x = 54). Abnormalities were found in the meiosis of these accessions, at variable frequencies. The most common abnormalities were those related to irregular chromosome segregation, which led to unbalanced gamete formation; but chromosome stickiness, cell fusion, and absence of cytokinesis were also recorded. Although some accessions have a low frequency of meiotic abnormalities, ensuring potentially good pollen viability, these cannot be used in hybridization due to a lack of sexual accessions with the same ploidy level.

A palaeoecological investigation into the role of fire and human activity in the development of montane grasslands in East Africa

Human activity has been widely implicated in the origin and expansion of montane grasslands in East Africa, yet little palaeoecological evidence exists to test whether these grasslands are natural or secondary. Pollen and charcoal data derived from two Holocene records in the Eastern Arc mountains of Tanzania are used as a case study to investigate the supposed secondary nature of montane grasslands in Africa. Fossil pollen data are used to detect vegetation change, and charcoal analysis is used to reconstruct fire history. The pollen data are characterised by stable proportions of local taxa suggesting permanence of grasslands throughout the past ~13,000 years. Recent increases in fire adapted taxa such as Morella point towards the development of a grassland/forest patch mosaic possibly associated with burning. However, robust evidence of human activity is absent from the records, which may be attributed to the late human occupation of the mountains. The records indicate long-term persistence of grasslands which, coupled with a lack of evidence of human activity, suggests that these grasslands are not secondary. These data support the hypothesis that grasslands are an ancient and primary component of montane vegetation in Africa, but that they experienced some expansion during the late Holocene as a result of changing fire regime.

Initial Estimates of Mercury Emissions to the Atmosphere from Global Biomass Burning

The average global annual mercury emission estimate from biomass burning (BMB) for 1997-2006 is 675 +/- 240 Mg/year. This is equivalentto 8% of all currently known anthropogenic and natural mercury emissions. By season, the largest global emissions occur in August and September, the lowest during northern winters. The interannual variability is large and region-specific, and responds to drought conditions. During this particular time period, the largest mercury emissions are from tropical and boreal Asia, followed by Africa and South America. They do not coincide with the largest carbon biomass burning emissions, which originate from Africa. Frequently burning grasslands in Africa and Australia, and agricultural waste burning globally, contribute relatively little to the mercury budget The released mercury from BMB is eventually deposited locally and globally and contributes to the formation of toxic bioaccumulating methyl mercury. Furthermore, increasing temperature in boreal regions, where the largest soil mercury pools reside, is expected to exacerbate mercury emission because of more frequent larger, and more intense fires.

The antiquity of Madagascar’s grasslands and the rise of C4 grassy biomes

AbstractAim Grasslands and savannas, which make up > 75% of Madagascar’s land area, have long been viewed as anthropogenically derived after people settled on the island c. 2 ka. We investigated this hypothesis and an alternative – that the grasslands are an insular example of the post‐Miocene spread of C4 grassy biomes world‐wide.Location Madagascar, southern Africa, East Africa.Methods We compared the number of C4 grass genera in Madagascar with that in southern and south‐central African floras. If the grasslands are recent we would expect to find fewer species and genera in Madagascar relative to Africa and for these species and genera to have very wide distribution ranges in Madagascar. Secondly, we searched Madagascan floras for the presence of endemic plant species or genera restricted to grasslands. We also searched for evidence of a grassland specialist fauna with species endemic to Madagascar. Plant and animal species endemic to C4 grassy biomes would not be expected if these are of recent origin.Results Madagascar has c. 88 C4 grass genera, including six endemic genera. Excluding African genera with only one or two species, Madagascar has 86.6% of southern Africa’s and 89.4% of south‐central Africa’s grass genera. C4 grass species make up c. 4% of the flora of both Madagascar and southern Africa and species : genus ratios are similar (4.3 and 5.1, respectively). Turnover of grasses along geographical gradients follows similar patterns to those in South Africa, with Andropogoneae dominating in mesic biomes and Chlorideae in semi‐arid grassy biomes. At least 16 monocot genera have grassland members, many of which are endemic to Madagascar. Woody species in frequently burnt savannas include both Madagascan endemics and African species. A different woody flora, mostly endemic, occurs in less frequently burnt grasslands in the central highlands, filling a similar successional niche to montane C4 grasslands in Africa. Diverse vertebrate and invertebrate lineages have grassland specialists, including many endemic to Madagascar (e.g. termites, ants, lizards, snakes, birds and mammals). Grassland use of the extinct fauna is poorly known but carbon isotope analysis indicates that a hippo, two giant tortoises and one extinct lemur ate C4 or CAM (crassulacean acid metabolism) plants.Main conclusions The diversity of C4 grass lineages in Madagascar relative to that in Africa, and the presence of plant and animal species endemic to Madagascan grassy biomes, does not fit the view that these grasslands are anthropogenically derived. We suggest that grasslands invaded Madagascar after the late Miocene, part of the world‐wide expansion of C4 grassy biomes. Madagascar provides an interesting test case for biogeographical analysis of how these novel biomes assembled, and the sources of the flora and fauna that now occupy them. A necessary part of such an analysis would be to establish the pre‐settlement extent of the C4 grassy biomes. Carbon isotope analysis of soil organic matter would be a feasible method for doing this.

Cultural landscape in mongolian tourism

The Mongolian steppes and their nomads, horses, herds and gers form a cultural landscape which is the region’s icon attraction, the central image in Mongolian marketing, the key feature of its flagship tourism products, and the most heavily commoditized component of its industry. In other Mongolian landscapes, and also in the steppes of neighboring regions and the grasslands of Africa, Australia, and North America, natural and cultural heritage are treated as separate attractions. The concept of cultural landscape is heavily used in a World Heritage context, has a significant role to play in the global tourism industry, and deserves further investigation as a tool for analysis.

Genomic relationships among diploid and hexaploid species of Andropogon (Poaceae)

Andropogon is a pantropical grass genus comprising 100-120 species and found mainly in the grasslands of Africa and the Americas. While the genomic relationships between many Andropogon species have been resolved by studying chromosome behavior in interspecific hybrids, relationships between the North and South American diploids have remained elusive. Further, the genome composition of two hexaploid species (including the important forage grass Andropogon lateralis Nees) has been unclear because of the strong hybridization barriers that exist between species. Consequently, genomic in situ hybridization was applied to shed light on these issues. The results confirmed that (i) both the South American (Andropogon selloanus (Hack.) Hack., Andropogon macrothrix Trin.) and North American (Andropogon gyrans Michx.) diploid species shared a common S genome and (ii) the S genome comprises just one of the three genomes in the hexaploids A. lateralis Nees and Andropogon bicornis L. The evolutionary and taxonomic implications of these findings are discussed.

Estimation of Soil Carbon Gains Upon Improved Management within Croplands and Grasslands of Africa

Many agro(eco)systems in Africa have been degraded as a result of past disturbances, including deforestation, overgrazing, and over exploitation. These systems can be managed to reduce carbon emissions and increase carbon sinks in vegetation and soil. The scope for soil organic carbon gains from improved management and restoration within degraded and non-degraded croplands and grasslands in Africa is estimated at 20–43 Tg C year−1, assuming that 'best' management practices can be introduced on 20% of croplands and 10% of grasslands. Under the assumption that new steady state levels will be reached after 25 years of sustained management, this would correspond with a mitigation potential of 4–9% of annual CO2 emissions in Africa. The mechanisms that are being put in place to implement the Kyoto Protocol - through C emission trading - and prevailing agricultural policies will largely determine whether farmers can engage in activities that enhance C sequestration in Africa. Mitigation of climate change by increased carbon sequestration in the soil appears particularly useful when addressed in combination with other pressing regional challenges that affect the livelihood of the people, such as combating land degradation and ensuring food security, while at the same time curtailing global anthropogenic emissions.

Over in the Grasslands

Let this wonderful book transport you to another continent and discover life on the grasslands of Africa. Helen Bromley, a literacy consultant in Essex, has plenty of original suggestions to help you make the most of this great story.

The distribution of sweetveld and sourveld in South Africa's grassland biome in relation to environmental factors

Abstract The distribution of sweet‐ and sourveld in relation to climate, parent material and soil nutrients has been examined in South Africa's grassland biome. Sourveld occurs in areas with high water supply and where parent material gives rise to soils with a low base status. Sweetveld occurs in areas with low water supply and where parent material gives rise to soils with a high base status. The distribution of sweet‐ and sourveld does not seem to be determined by base status itself, but by the concentration of available phosphorus and the size of the readily mineralizable nitrogen pool in the soil. The difference between the temperatures in the growth (wet) and no‐growth (dry) seasons also appears important, but the relation is not clear. We propose that aspects of the environment which promote carbon assimilation (water supply and temperature) in relation to nutrient supply (soil fertility, water supply and temperature) determine the forage quality of grassland vegetation. Sourveld occurs where carbo...