Tag: grasslands
The ENRICH Bot, a smartphone application measuring fruit and vegetable intake and food choice motives: Development and validation for the case of urban Kenyan consumers
Understanding the complexity of food consumption and choice motivation is vitally important for guiding business and policy efforts towards healthier nutritional intake. We need that insight in order to develop, offer, and design food and nutrition interventions that better fit the diverse range of consumers and eventually lead to a higher intake of healthy foods (e.g. fruit and vegetables). The rise in ownership of smartphones and technical developments provide the opportunity to apply new and innovative metrics. The overall aim of this study was to develop and validate a tool/metrics, the ENRICH Bot, that can provide reliable information on fruit and vegetable intake and food choice motives (FCM) in real time and in situ from urban consumers in low- and middle-income countries (LMICs) with an application to urban consumers living in Nairobi (Kenya).
The imperata grasslands of tropical Asia: area, distribution and typology.
The rehabilitation or intensified use of Imperata grasslands will require a much better understanding of their area, distribution, and characteristics. We generated estimates of the area of Imperata grasslands in tropical Asia, and suggested a typology of Imperata grasslands that may be useful to define the pathways toward appropriate land use intensification. We conclude that the area of Imperata grasslands in Asia is about 35 million ha. This about 4% of the total land area. The countries with the largest area of Imperata grasslands are Indonesia (8.5 million ha) and India (8.0 million ha). Those with the largest proportion of their surface area covered with Imperata are Sri Lanka (23%), the Philippines (17%), and Vietnam (9%). Laos, Thailand, Myanmar, and Bangladesh evidently all have similar proportions of their land area infested with Imperata (about 3 to 4%). Malaysia (< 1%), Cambodia (1%), and the southern part of China (2%) have but a minor proportion of their total land area in Imperata. The species was found widely distributed on the full range of soil orders. It occupied both fertile (e.g. some of the Inceptisols and Andisols) and infertile soils (Ultisols and Oxisols) across a wide range of climates and elevations. Imperata lands fall into four mapping scale-related categories: Mega-grasslands, itmacro-grasslands, meso-grasslands, and micro-grasslands. The mega-grasslands are often referred to as ‘sheet Imperata’. They are the large contiguous areas of Imperata that would appear on small-scale maps of say 1:1,000,000. We propose that this basic typology be supplemented with a number of additional components that have a key influence on intensification pathways: land quality, market access, and the source of power for tillage. The typology was applied in a case study of Indonesian villages in the vicinity of Imperata grasslands. We propose an international initiative to map and derive a more complete and uniform picture of the area of the Imperata grasslands. This should include selected studies to understand conditions at the local level. These are critical to build the appreciation of change agents for the indigenous systems of resource exploitation, and how they relate to local needs, values and constraints.
Agroforestry innovations for imperata grassland rehabilitation: workshop recommendations
Agroforestation of grasslands in Southeast Asia: WaNulCAS model scenarios for shade-based imperata control during tree establishment
In the stage of land use evolution where smallholder tree-based systems are desirable as replacement of Imperata cylindrica (and similar) grasslands, agroforestry can provide a gradual and rewarding approach to the transition. There tends to be, however, a gap between the last opportunity for food crop interplanting and canopy closure providing shade-based control of grass and weed growth. In such period, regrowth of Imperata enhances the risk of fire and failure of tree establishment. We analyzed the duration of this ‘Imperata regrowth window’, for a range of planting patterns and choice of tree species in Lampung (Indonesia) and northern Mindanao (the Philippines). Simulations of agroforestation scenarios with the WaNuLCAS model (‘water, nutrient and light capture in agroforestry systems’) focuss on the Imperata regrowth window as the period between 50 percent and 15 percent of ground-level light availability. The simulation results first of all confirm a well-known fact: young trees of most species are not able to compete with Imperata and partial weeding around the tree stem base is absolutely necessary to get most trees started, with the possible exception of Paraserianthes falcataria. Although Acacia mangium is a fast growing tree, a more intensive weeding regime will double tree growth. The improvement of initial tree growth speeds up tree canopy closure and reduces subsequent Imperata regrowth window by two to more than five years according to the model, with periods longer than five years associated with slow initial growth rates. There is, according to the model, only limited opportunity to reduce risk exposure by modifying tree spacing.
Nitrogen mineralization in soils under grasses and under trees in a protected Venezuelan savanna
Nitrogen mineralization was evaluated in soils beneath the most common woody species growing isolated within the grass matrix of a Venezuelan Trachypogon savanna, which has been protected from fire and cattle grazing since 1961. Adult trees of three evergreen species, Byrsonima crassifolia (L) H. B. K., Curatella americana L., and Bowdichia virgilioides H. B. K; and two deciduous, Godmania macrocarpa Hemsley and Cochlospermun vitifolium (Wild) Spreng were selected. The amount of N mineralized (NH4+-N+NO3-N) during 15 weeks of laboratory incubation of soils collected from beneath trees, was significantly higher (p<0.01) than those from under grasses. Values of N mineralized on soil from under trees were from 21.28 to 82.65% greater than for soil from under grasses. A highly significant (p<0.01) positive correlation, for all soils, was found between Nm and SOC, and between Nm and Nt. The higher N mineralization rates under trees would reflect a higher soil biological activity, due to higher SOC and Nt, of the soils under the tree canopies than those under grasses. The N availability values obtained under all species reveal the importance these trees have for creating enriched areas on generally oligotrophic soils.Nitrogen mineralized in the soil from beneath evergreen trees was significantly (p<0.01) higher than from under deciduous trees, being 25.87% higher on average. Similarly to the relation found for all soils, a highly significant (p<0.01) positive correlation between Nm and SOC and between Nm and Nt was also obtained for soils beneath all trees, indicating the importance of SOC and Nt for nitrogen mineralization processes in this savanna. The higher SOC and Nt contents found under evergreen trees are probably due to the longer time they have been established on the site as compared to the deciduous ones.The chemical quality of fresh fallen leaves (as measured by their lignin/nitrogen ratio) did not seem to influence the quality of the SOM (as measured by C/N ratio), since the C/N ratio was not statistically different for the soils under the two groups of trees. Apparently, whatever the chemical quality of the fresh fallen leaves (higher lignin/nitrogen ratio in evergreen trees), the humification processes in this savanna soil environment seems to homogenize the SOM beneath both types of trees.
Can rehabilitation of Imperata grasslands help to protect the remaining rain forests?
Forest conversion for unsustainable land use practices in the humid tropics often results in the formation of coarse grasslands, dominated by imperata cylindrica. Rehabilitation of these grasslands may help to alleviate the pressure on further forest conservation. Evidence in favour and against this hypothesis in review on the basis of results of phase 1of the global Alternatives to slash-and-Burn project in Indonesia.
Effects of human-livestock-wildlife interactions on habitat in an Eastern Kenya rangeland
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.
Critical climate periods for grassland productivity on China’s Loess Plateau
Strong correlations between aboveground net primary productivity (ANPP) of grasslands and mean annual temperature or precipitation have been widely reported across regional or continental scales; however, inter-annual variation in these climate factors correlates poorly with site-specific ANPP. We hypothesize that the reason for these weak correlations is that the impacts of climatic variation on grassland productivity depend on the timing and intensity of variation in temperature and precipitation. In this study, long-term records of grassland productivity on the Loess Plateau in China were related with daily temperature and precipitation during 1992–2011 using Partial Least Squares (PLS) regression to test the above-mentioned hypothesis. Our results suggested that temperature increases during the early stage of the growing season (April–May) were positively correlated with ANPP. However, these effects were canceled out when this phase was followed by a hot and dry summer (June–July). Impacts of drought and heat in August on productivity were negligible. Increased temperature and precipitation during the senescence period (September–October) and a warmer dormancy phase (November–March) were negatively correlated with productivity in the following year, while precipitation during the dormancy period had no detectable effects. Climatic variability in summer has thus far been the dominant driver of temporal variation in grassland productivity. Warming during winter and spring currently play minor roles, but it seems likely that the importance of these secondary impacts may increase as warming trends continue. This evaluation of climate variability impacts on ecosystem function (e.g. grassland productivity) implies that not only the magnitude but also the timing of changes in temperature and precipitation determines how the impacts of climate changes on ecosystems will unfold. © 2016 Elsevier B.V.
Managing grasslands for planet and profits: The essential role of pastoralism
This brief shares key insights from the programme’s development at scale of effective livestock management interventions, learning from the environmental value of nomadic pastoralism.