Heterotrophic respiration is a major component of the soil C balance however we critically lack understanding of its variation upon conversion of peat swamp forests in tropical areas. Our research focused on a primary peat swamp forest and two oil palm plantations aged 1 (OP2012) and 6 years (OP2007). Total and heterotrophic soil respiration were monitored over 13 months in paired control and trenched plots. Spatial variability was taken into account by differentiating hummocks from hollows in the forest; close to palm from far from palm positions in the plantations. Annual total soil respiration was the highest in the oldest plantation (13.8 ± 0.3 Mg C ha-1 year-1) followed by the forest and youngest plantation (12.9 ± 0.3 and 11.7 ± 0.4 Mg C ha-1 year-1, respectively). In contrast, the contribution of heterotrophic to total respiration and annual heterotrophic respiration were lower in the forest (55.1 ± 2.8%; 7.1 ± 0.4 Mg C ha-1 year-1) than in the plantations (82.5 ± 5.8 and 61.0 ± 2.3%; 9.6 ± 0.8 and 8.4 ± 0.3 Mg C ha-1 year-1 in the OP2012 and OP2007, respectively). The use of total soil respiration rates measured far from palms as an indicator of heterotrophic respiration, as proposed in the literature, overestimates peat and litter mineralization by around 21%. Preliminary budget estimates suggest that over the monitoring period, the peat was a net C source in all land uses; C loss in the plantations was more than twice the loss observed in the forest.
Tag: land use change
Benefit sharing in context: A comparative analysis of 10 land-use change case studies in Indonesia
Key points
- In the absence of robust national or subnational policies for benefit sharing, land-use change initiatives in Indonesia have developed their own approaches to distributing benefits. At the local level, support and capacity building are needed to strengthen intermediary institutions in order to improve governance and increase legitimacy when deciding how to share benefits.
- Nonmonetary benefits such as land tenure, capacity building, infrastructure and access to natural resources have been especially important. However, in some cases there are nonmonetary burdens associated with intended benefits.
- The legitimacy of benefit-sharing arrangements is determined more by the actors involved than the type of land-use change associated with them. Conservation initiatives, REDD+ projects and oil palm initiatives all exhibited both high and low levels of legitimacy in their benefit-sharing arrangements.
- The legitimacy of benefit-sharing arrangements can be compromised by the lack of broad consultation with local actors including customary authorities, lack of community control over access to land snd limited livelihoods options for communities.
Water Efficient Alternative Crops for Sustainable Agriculture along the Tarim Basin: A Comparison of the Economic Potentials of Apocynum pictum, Chinese Red Date and Cotton in Xinjiang, China
Study on nutrient compositions of and processed products developed from son tra (Docynia indica (Wall.)) – Second part: In-depth study of bioactive substances in son tra fruit and its processed product development.
Effects of land‐use change on community diversity and composition are highly variable among functional groups
In order to understand how the effects of land‐use change vary among taxa and environmental contexts, we investigate how three types of land‐use change have influenced phylogenetic diversity (PD) and species composition of three functionally distinct communities: plants, small mammals, and large mammals. We found large mammal communities were by far the most heavily impacted by land‐use change, with areas of attempted large wildlife exclusion and intense livestock grazing, respectively, containing 164 and 165 million fewer years of evolutionary history than conserved areas (~40% declines). The effects of land‐use change on PD varied substantially across taxa, type of land‐use change, and, for most groups, also across abiotic conditions. This highlights the need for taxa‐specific or multi‐taxa evaluations, for managers interested in conserving specific groups or whole communities, respectively. It also suggests that efforts to conserve and restore PD may be most successful if they focus on areas of particular land‐use types and abiotic conditions. Importantly, we also describe the substantial species turnover and compositional changes that cannot be detected by alpha diversity metrics, emphasizing that neither PD nor other taxonomic diversity metrics are sufficient proxies for ecological integrity. Finally, our results provide further support for the emerging consensus that conserved landscapes are critical to support intact assemblages of some lineages such as large mammals, but that mosaics of disturbed land‐uses, including both agricultural and pastoral land, do provide important habitats for a diverse array of plants and small mammals.
Landscape-scale variability of soil health indicators: effects of cultivation on soil organic carbon in the Usambara Mountains of Tanzania
Land-use change continues at an alarming rate in sub-Saharan Africa adversely affecting ecosystem services provided by soil. These impacts are greatly understudied, especially in biodiversity rich mountains in East Africa. The objectives of this study were to: conduct a biophysical baseline of soil and land health; assess the effects of cultivation on soil organic carbon (SOC); and develop a map of SOC at high resolution to enable farm-scale targeting of management interventions. Biophysical field surveys were conducted in a 100 km2 landscape near Lushoto, Tanzania, with composite soil samples collected from 160 sampling plots. Soil erosion prevalence was scored, trees were counted, and current and historic land use was recorded at each plot. The results of the study showed a decline in SOC as a result of cultivation, with cultivated plots (n = 105) having mean topsoil OC of 30.6 g kg1, while semi-natural plots (n = 55) had 71 g OC kg1 in topsoil. Cultivated areas were also less variable in SOC than semi-natural systems. Prediction models were developed for the mapping of SOC based on RapidEye remote sensing data for January 2014, with good model performance (RMSEPcal = 8.0 g kg1; RMSEPval = 10.5 g kg1) and a SOC map was generated for the study. Interventions will need to focus on practices that increase SOC in order to enhance productivity and resilience of the farming system, in general. The high-resolution maps can be used to spatially target interventions as well as for monitoring of changes in SOC. © 2015, The Author(s).
Environmental services and land use change in Southeast Asia: from recognition to regulation or reward?
Awareness of environmental services and land use change in Southeast Asia is high among scientists, policymakers, and society. In the case of transboundary smoke, the level of awareness and concern in the region is high, but subsides in between periods of’crisis’. Although there is a rising level of awareness of habitat loss and associated loss of genetic diversity, the basic cause-effect relationships underlying the ecological roles of biodiversity are still debated. Degradation of watershed functions is the most mature of our three meso-scale environmental topics; indeed it shows signs of being’fossilized’ by vested interests in the present consensus. Land use planning and other regulatory approaches have had little success. Policy instruments for achieving meso-level environmental policy objectives through changing incentives such as payment schemes for environmental services, have not been tested widely in Southeast Asia (or anywhere else). Further research and experimentation needs to incorporate strategic consideration of processes and spatial scales of environmental impacts and resource governance.
Land use change patterns and livelihood dynamics on the slopes of Mt. Kilimanjaro, Tanzania
This study is about changes in land use and interactions of land use change and livelihoods in the Chagga farming system on the slopes of Mt. Kilimanjaro, Tanzania. An aerial photo interpretation and fragmentation analysis of the years 1961, 1982 and 2000 was conducted covering approximately the Kirua Vunjo Division, a transect of 152 km2 from the forest reserve edge to the plains. Earlier changes were traced from literature review. The results show the expansion of cultivation to more marginal land down the slope, the disappearance and extreme fragmentation of bush land and appearance and expansion of settlements. The home garden area has experienced some specific internal change, but has not expanded down the slope. In the 1960s there were small open fields and patches of grazing lands amongst home gardens. In the 1980s the area was more uniformly covered by homegardens. Since then it has become patchy again as new homesteads have been built on subdivided farms and more food is produced on the higher slopes. Population pressure and the ensuing expansion of agriculture to more marginal land, intensification of the homegarden system, together with climate changes affecting the water supplies, have caused changes in farmers’ livelihoods. As land scarcity now hinders expansion of agriculture, farm size has seriously decreased, common resources have become scarce, and prices of coffee in the world market remain low, farmers are trying to intensify and diversify their farm production. Local initiative is leading to change, but the locally conceived alternatives are too few and lack integrated approaches of technical agricultural research, economic analysis, and policy studies and reforms. Non-agricultural activities and paid employment are becoming increasingly important. However, due to considerable entry barriers to remunerable off-farm jobs, not all households enjoy equal access to attractive non-farm opportunities. The future welfare of the area will depend on increasing the marketable knowledge and skills of the population that will enable it to become integrated in the economy of the region and the country.
Soil chemical properties dynamics as affected by land use change in the humid forest zone of Cameroon
The conversion of forests to other forms of land use has profound effects on the distribution and supply of soil nutrients. Understanding the effects of land use on soil is essential for addressing agroecosystem transformation and sustainable land productivity. Although soil carbon stock has been previously examined in the humid forest zone of Cameroon, the dynamic and interactions between other soil chemical properties has been poorly addressed to date. The present study used the quadrat approach to assess the effect of four land use types (secondary forest, fallow, cocoa plantation and mixed cropping) on soil chemical properties. Soil samples were collected at two different depths (0-10, 10-30 cm) in all land use types and analyzed for pH, total carbon, soil organic carbon, total nitrogen, cation exchange capacity (CEC), calcium (Ca), potassium (K), magnesium (Mg) and boron (B). Land use type significantly affected B, Ca, K and pH: in general, these properties were higher in cocoa plantation and mixed cropping than in secondary forest and fallow. All soil properties were significantly greater in the upper than in the lower soil depth. In addition, all soil properties differed significantly among sites and villages within sites. Pearson correlations between soil chemical properties were positive and generally significant in the four land use types, except for some correlations with B, pH and CEC. Despite the fact that some of the fundamental soil chemical properties (carbon, nitrogen, CEC and Mg) did not differ among the four land use types, high density tree-based production systems are recommended for the storage of these elements in the soils.
Carbon balance in rubber (Hevea brasiliensis) plantations: A review on uncertainties at plot and landscape level
Rapid expansion of natural rubber plantations in South-East Asia and other regions has greatly altered ecosystem based carbon (C) stocks with potential impacts on climate change mitigation and future C trading opportunities. Therefore, reliable estimations of carbon sequestration and emission at the landscape level after land cover transition from forest, swidden agriculture and other land use types are needed. We reviewed studies on C stocks and dynamics in rubber plantations considering the contribution of aboveground and belowground biomass, soil organic matter, collected latex and other minor components. C sequestration occurred after conversion of arable land to rubber plantations while C losses usually prevailed if forest was converted to rubber. These general trends strongly depended on local climate conditions and soil properties as well as on topography. Non-traditional planting of rubber under subtropical conditions with a dryer climate and at high elevations (300–1000 m above sea level) decreased the C sequestration potential of rubber. We show how rotation length, rubber clone, and management strategies like tapping frequency or planting density affect C stocks, discuss the uncertainties in C stock estimation and highlight improved approaches. An important conclusion is that upscaling of C stocks and dynamics under different climate scenarios and rotation lengths to a regional level requires the use of time averaged C stocks. Enhanced remote sensing techniques can greatly improve C stock estimates at the regional level, allowing for an accounting of the variability caused by terrain and plantation properties. A partial life cycle assessment of rubber production revealed greenhouse gas emissions as a minor contribution when compared to land use change effects on plant and soil C stocks and C accumulation in latex, wood products and seed oil. The review highlights scantily explored topics and proposes directions for future studies, which should decrease uncertainties in C estimates in rubber dominated landscapes.