Human alteration of the global environment has triggered the sixth major extinction event in the history of life and caused widespread changes in the global distribution of organisms. These changes in biodiversity alter ecosystem processes and change the resilience of ecosystems to environmental change. This has profound consequences for services that humans derive from ecosystems. The large ecological and societal consequences of changing biodiversity should be minimized to preserve options for future solutions to global environmental problems.

Consequences of changing biodiversity

Oil palm is one of the world's most rapidly increasing crops. We assess its contribution to tropical deforestation and review its biodiversity value. Oil palm has replaced large areas of forest in Southeast Asia, but land-cover change statistics alone do not allow an assessment of where it has driven forest clearance and where it has simply followed it. Oil palm plantations support much fewer species than do forests and often also fewer than other tree crops. Further negative impacts include habitat fragmentation and pollution, including greenhouse gas emissions. With rising demand for vegetable oils and biofuels, and strong overlap between areas suitable for oil palm and those of most importance for biodiversity, substantial biodiversity losses will only be averted if future oil palm expansion is managed to avoid deforestation.

How will oil palm expansion affect biodiversity

How much palm oil do we need

Influence of slash-and-burn farming practices on fallow succession and land degradation in the rainforest region of Madagascar

This study in the wake of 1990s fire catastrophes identifies and analyzes underlying causes of vegetation fires in eight locations across Borneo and Sumatra. Multidisciplinary and multiscale analysis integrates geospatial technologies with varied social research approaches and participatory mapping. It helps fill a void of site-specific evidence on diverse underlying causes of the Indonesian fires, despite emerging consensus on macrolevel causes and impacts, and policy debates on preventing future fire disasters. Our most important findings include confirmation of multiple direct and underlying fire causes at each of the eight locations, no single dominant fire cause at any site, and wide differences in fire causes among sites. Conclusions emphasize the importance of location specific studies within a regional analytical context. Our “hybrid” research methods demonstrate the explanatory power of integrating geospatial and social analysis techniques, and the benefits of analyzing fire causes and impacts at multiple scales in varied locations across diverse regions.

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Fire, People and Pixels: Linking Social Science and Remote Sensing to Understand Underlying Causes and Impacts of Fires in Indonesia

Should policy makers - or anyone else - care about millions of ha of Imperata grassland? The answer depends on the balance between costs of conversion to other uses and the net benefits produced in economic growth, poverty alleviation, and protection of the environment. The first section on Imperata economics sets up the analytical framework to address this question and draws on the wider development economics literature to consider whether growth and poverty alleviation are conflicting or complementary objectives. Although evidence is limited, it suggests smallholder-based agroforestry could provide the same economic growth with greater poverty alleviation than large-scale forestry estates. There is, however, no substitute for project appraisal for specific settings. The second section on Imperata policy reviews whether policy distortions and market failures provide a sufficient rationale for direct policy intervention to promote tree planting on Imperata grasslands. Estimates of imputed values of carbon sequestration to alleviate global warming are presented for Acacia mangium and rubber agroforestry. The conclusion summarizes the policy research agenda and examines the desirability and feasibility of policy intervention to promote carbon sequestration through Imperata grassland conversion to tree-based systems.

http://www.mekonginfo.org/assets/midocs/0001579-economy-imperata-economics-and-policy.pdf

Imperata economics and policy

This is a report of a collaborative research project, 'Improving smallholder farming systems in Imperata areas of Southeast Asia: a bioeconomic modelling approach' sponsored by the Center for international Forestry Research and the Australian Centre for International Research. The nature of the Imperata problem and the methodology is outlined. Imperata is essentially restricted to upland areas, since it does not coexist with lowland rice farming. There is a section on bioeconomic analysis of traditional smallholder 'shifting cultivation' farming systems where the fallow is Imperata and another contains a series of case study descriptions of successful tree growing by smallholders on Imperata grasslands. The core modelling work of the project is reported. Various tree-based interventions are modelled with and without an animal component. Some of these modelled farming systems are already in place in farmers' fields. In these cases, possible management or policy interventions analysed with the models can point the way to productive and economic improvements. In other cases, the farming systems modelled are 'experimental' in nature. Imperata grows on uplands of various slopes, but some special attention is given to Imperata on steeply sloping land where soil erosion is a particular problem. Finally, two key issues in relation to tree growing on Imperata grassland, fire control and carbon sequestration, are addressed. These are viewed both from the viewpoints of the individual smallholder and of the broader society. This is an overview and compilation of studies, many of which were previously reported in a series of project papers published by Centre for Resource and Environmental Studies, Australian National University between 1995 and 1998.

Improving Smallholder Farming Systems in Imperata Areas of Southeast Asia: Alternatives to Shifting Cultivation

Napier grass strips are gaining some acceptance in Southeast Asia as a vegetative means of soil erosion control, due to the relative ease of establishment and management. In addition, the napier grass strips aid productivity of agroforestry systems by providing mulch or by being fed to livestock. In this paper, a bioeconomic comparison of different ways of utilising the napier grass cuttings is undertaken. The three uses examined for the cuttings were: as mulch in the alley areas, sold as fodder, and fed to animals with manure applied back to the system. The analysis linked the soils-oriented SCUAF model with economic and animal component models. SCUAF was parameterized using field data based on farmer interviews and field visits. Farmer interviews and field visits were conducted at Claveria, Misamis Oriental to gather additional data regarding costs and returns associated with animal production, and also to obtain the farm gate price of napier. Predicted biophysical results produced by the SCUAF model showed that application of napier grass cuttings, back into the system, directly as mulch or indirectly as animal manure resulted in higher maize and napier yields, lower soil erosion rates, and less of a reduction in soil mineral nitrogen and soil labile carbon levels. The comparison was made with the case where napier was sold off-farm as fodder. Cost-benefit analysis showed that higher economic returns were gained when napier grass cuttings were fed to animals, rather than applied directly as mulch. This economic benefit was attributed to the draught and transport services rendered by the animal and to a change in the value of the animals. This analysis highlights the value of utilizing animals within a napier grass strip system for control of erosion.

Napier grass strips and livestock: a bioeconomic analysis

Considerable resources have been expended promoting hedgerow intercropping with shrub legumes to farmers in the Philippine uplands. Despite the resources committed to research and extension, persistent adoption by farmers has been limited to low cost versions of the technology including natural vegetation and grass strips. In this paper, cost-benefit analysis is used to compare the economic returns from traditional open-field maize farming with returns from intercropping maize between leguminous shrub hedgerows, natural vegetation strips and grass strips. An erosion/productivity model, Soil Changes Under Agroforestry, was used to predict the effect of erosion on maize yields. Key informant surveys with experienced maize farmers were used to derive production budgets for the alternative farming methods. The economic incentives revealed by the cost-benefit analysis help to explain the adoption of maize farming methods in the Philippine uplands. Open-field farming without hedgerows has been by far the most popular method of maize production, often with two or more fields cropped in rotation. There is little persistent adoption of hedgerow intercropping with shrub legumes because sustained maize yields are not realised rapidly enough to compensate farmers for establishment and maintenance costs. Natural vegetation and grass strips are more attractive to farmers because of lower establishment costs, and provide intermediate steps to adoption. Rural finance, commodity pricing and agrarian reform policies influence the incentives for maize farmers in the Philippine uplands to adopt and maintain hedgerow intercropping.

Cost-benefit analysis of alternative forms of hedgerow intercropping in the Philippine uplands

Soil erosion in the Philippine uplands is severe. Hedgerow intercropping is widely advocated as an effective means of controlling soil erosion from annual cropping systems in the uplands. However, few farmers adopt hedgerow intercropping even in areas where it has been vigorously promoted. This may be because farmers find hedgerow intercropping to be uneconomic compared to traditional methods of farming. This paper reports a cost-benefit analysis comparing the economic returns from traditional maize farming with those from hedgerow intercropping in an upland community with no past adoption of hedgerows. A simple erosion/productivity model, Soil Changes Under Agroforestry (SCUAF), is used to predict maize yields over 25 years. Economic data were collected through key informant surveys with experienced maize farmers in an upland community. Traditional methods of open-field farming of maize are economically attractive to farmers in the Philippine uplands. In the short term, establishment costs are a major disincentive to the adoption of hedgerow intercropping. In the long term, higher economic returns from hedgerow intercropping compared to open-field farming are realised, but these lie beyond farmers' limited planning horizons.

K Menz

Papers

Imperata economics and policy

Improving Smallholder Farming Systems in Imperata Areas of Southeast Asia: Alternatives to Shifting Cultivation

Napier grass strips and livestock: a bioeconomic analysis

Cost-benefit analysis of alternative forms of hedgerow intercropping in the Philippine uplands

A cost-benefit analysis of hedgerow intercropping in the Philippine uplands using the SCUAF model