Land use change and its impact on soil properties using remote sensing, farmer decision rules and modelling in rural regions of Northern Vietnam

After the Indo China war in 1954, a dramatic rise in population in Northwest Vietnam led to an increased demand of agricultural land for food security requirements. Slash and burn systems which existed for many hundreds of years were replaced by intense cash crop systems, particularly maize production. Maize cropping was further expanded to steeper sloping areas, resulting in a risk of soil degradation. Therefore, investigating Land Use Change (LUC) and its impact on soil properties were considered in this study. The study aimed to identify LUC in 1954, 1973, the 1990s and 2007 in Chieng Khoi commune, Yen Chau district, Son La province, Vietnam using available remote sensing data. Furthermore, a detailed land use map classification method was developed using farmers decision rules. Based on farmers crop decision rules and, food requirement and population information, a simple LUC model was developed to simulate LUC annually from 1954 to 2007. Moreover, total soil nitrogen and carbon were determined under a chronosequence of intense cultivation. Thus, developing a modelling tool had the aim to assess the impacts of LUC on soil fertility at watershed level. The first case study (Chapter 3) presented the LUC assessment, using available remote sensing data combined with farmer information. Forest areas decreased from 1954 to 2007, except in the 1990s because of policies that aimed to encourage and support afforestation programmes to increase forest land. However, planted forest has since decreased again since 1999 whereas agricultural land has increased dramatically. Agricultural land expanded to both natural forest and planted forest areas until 2007 legally (with encouragement of agroforestry) and illegally thereafter (at the border between cultivated land and forest). The establishment of an artificial lake in Chieng Khoi commune opened the accessibility to forest land surrounding the lake, with a forest area of 929 ha remaining in 2007 compare to more than 2,500 ha in 1954. Paddy rice areas did not change because of their specific location (lower and flat lands), but production increased and was intensified by two cropping seasons per year due to irrigation improvements and a continuous water supply from the artificial lake. The second case study (Chapter 4) presented the development of a LUC model, using the outputs from the first case study comprising farmers decision rules and food requirements for an increased population. For later periods, the influence of market orientation factor was considered. The model successfully simulated the expansion of cultivation areas and replacement of forest land by agricultural land. Simulations were at accepted level of accuracy comparing actual and simulated LUC (Goodness-of-fit GOF values greater than 0.7 and Figure of merit - FOM values greater than 50%). The third case study (Chapter 5) demonstrated an investigation of the soil fertility dynamic under intense cultivation and the development of a simple dynamic and spatially-explicit modelling tool to assess the changes in soil fertility. The Dynamic of total Carbon and Nitrogen distribution (DyCNDis) model was constructed using field data combined with literature information. The field data showed that, under a decade of maize mono cultivation in slope areas, both nitrogen and carbon were largely depleted. Furthermore, the DyCNDis model showed an acceptable level of validation (modelling efficiency EF of 0.71 and root mean square error - RMSE of 0.42) to simulate nitrogen and carbon under intense maize cultivation at watershed level. Additionally, the model identified hotspot areas of 134 ha (18.9% of total upland cultivation areas) that are threatened by soil degradation through intense cultivation over a long-term period. In conclusion, the combination of qualitative and quantitative approaches allowed assessing impacts of LUC on environmental services such as soil fertility through the developed DyCNDis modeling tool. The combination of improved LUC analysis with a simple spatial dynamic soil fertility modeling tool may assist policy makers in developing alternative implementation strategies for local stakeholders in regions which face data limitations. The modelling tools developed in this study were able to successfully simulate LUC and to identify locations where soil conservation methods at watershed level need most urgently to be applied to avoid soil degradation. The model tools were able to simulate the trends rather than values of agricultural area expansion and reduction of soil nitrogen and carbon. The developed approaches could be linked and coupled to other modelling tools to economically consider benefits or ecological concerns toward sustainable crop production in remote and rural regions.Nach Ende des Indochinakrieges führten ein starkes Bevölkerungswachstum und der damit steigende Bedarf an Nahrungsmitteln in Nordwestvietnam zu einer enormen Ausweitung der landwirtschaftlich genutzten Flächen. Intensivierte Landwirtschaft, insbesondere im Maisanbau, ersetzte die traditionellen Landnutzungssysteme, die hauptsächlich auf Brandrohdung basierten und zuvor für Jahrhunderte Bestand hatten. Vor allem der Maisanbau wurde zunehmend auf Steillagen ausgeweitet, was beträchtliche Risiken der Bodendegradierung nach sich zog. Diese Dissertation befasst sich mit der Erforschung der Landnutzungsänderungen und ihren Auswirkungen auf die Bodeneigenschaften der betroffenen Flächen. Das übergeordnete Ziel ist die Analyse der Landnutzungsänderungen in der Kommune Chieng Khoi des Distrikts Son La in den Jahren 1954, 1973, den 1990er Jahren sowie 2007. Hierfür wurden verfügbare Fernerkundungsdaten verwendet. Zudem wurde eine detaillierte Klassifizierungsmethode zur Erstellung von Landnutzungskarten entwickelt. Basierend auf den Anbauentscheidungen der Kleinbauern in der Studienregion, Nahrungsmittelbedarf und demographischen Daten, wurde ein einfaches dynamisches und räumlich-explizites Modell zur Simulation der Landnutzungsänderungen im Zeitraum von 1954 bis 2007 erstellt. Gesamtstickstoff und der gesamte Kohlenstoffgehalt unter intensiver Landnutzung wurden durch Feldbeprobungen und Laboranalysen bestimmt. Somit hatte die Modellentwicklung das Ziel, den Einfluss der Landnutzungsänderungen auf die Bodenfruchtbarkeit im Wassereinzugsgebiet des Chieng Khoi-Sees zu analysieren und zu bewerten. Die erste Fallstudie dieser Dissertation behandelt die Bewertung der Landnutzungsänderungen mit Hilfe von Fernerkundungsdaten und Interviews mit Kleinbauern. Nahezu der gesamte Untersuchungszeitraum war durch Abholzung geprägt. Eine Ausnahme stellen die 1990er Jahre dar, in denen Aufforstung durch diverse politische Maßnahmen gefördert wurde. Diese kurze Phase der Aufforstung endete jedoch bereits im Jahr 1999, als mit massiver Abholzung begonnen wurde. Bis ins Jahr 2007 wurden sowohl Primärwälder, als auch wieder aufgeforstete Flächen zur Erschließung von Ackerland gerodet. Dies geschah zum einen auf legalem Weg im Rahmen von staatlich geförderten Agroforstprogrammen, zum anderen illegal an den Grenzbereichen der Ackerflächen zu Wäldern. Insbesondere die Errichtung des Chieng Khoi-Stausees ermöglichte die landwirtschaftliche Erschließung umliegender Waldgebiete. Als Konsequenz gingen die Waldgebiete von 2.500 Hektar in 1954 auf 929 Hektar in 2007 zurück. Im Gegensatz zu Hanglagen hatte die Errichtung des Stausees lediglich geringe Auswirkungen auf den Nassreisanbau in flachen Lagen und Tälern. Dennoch wurden auch im Nassreisanbau Veränderungen registriert. Die konstante Wasserverfügbarkeit durch den Stausee ermöglichte die Einführung eines zweiten Produktionszyklus pro Jahr. Außerdem konnten durch intensivere Bewirtschaftungsmethoden die Erträge gesteigert werden. In der zweiten Fallstudie wird ein Modell zur Simulation von Landnutzungsänderungen entwickelt. Hierfür werden die Ergebnisse der ersten Fallstudie, die Anbauentscheidungen der Kleinbauern in der Studienregion und der Nahrungsmittelbedarf einer wachsenden Bevölkerung herangezogen. Mit Hilfe des Modells konnte die Ausweitung der landwirtschaftlich genutzten Flächen sowie die dadurch bedingte Abholzung erfolgreich simuliert werden. Simulierte Ergebnisse lagen beim Vergleich mit historischen Daten im Toleranzbereich. Die dritte Fallstudie befasst sich mit der Untersuchung der Entwicklung der Bodenfruchtbarkeit in intensiven Ackerbausystemen. Zudem wurde ein einfaches Modellierungstool zur Bewertung der Änderungen der Bodenfruchtbarkeit entwickelt. Das Modell zur Analyse der Entwicklung der gesamten Kohlenstoff- und Stickstoffverteilung (DyCNDis) wurde mit Hilfe von im Feld erhobenen Primärdaten sowie Sekundärdaten aus relevanter Literatur entwickelt. Anhand der Primärdaten konnte gezeigt werden, dass an Hanglagen sowohl der Kohlenstoff- als auch der Stickstoffgehalt im Boden bereits nach einem Jahrzehnt Maisanbau drastisch abgenommen hatte. Zudem konnte das DyCNDis-Modell zufriedenstellend validiert werden. Demnach ist das Modell geeignet, um Kohlenstoff- und Stickstoffgehalte im Boden unter intensivem Maisanbau für Wassereinzugsgebiete zu simulieren. Außerdem konnten Standorte, welche bei dauerhafter landwirtschaftlicher Nutzung besonders von Bodendegradation bedroht waren, identifiziert werden. Diese Standorte hatten eine Gesamtfläche von 134 ha, was 18,9% der gesamten Ackerfläche an Hanglagen in der Forschungsregion entspricht. Zusammenfassend kann gesagt werden, dass die Kombination qualitativer und quantitativer Forschung eine hinreichende Bewertung der Einflüsse von Landnutzungsänderungen auf Ökosystemdienstleistungen ermöglicht. Dynamische Veränderungen der Landnutzung und Bodenfruchtbarkeit werden, wie in der Vergangenheit, auch in Zukunft auftreten. Besonders in Regionen mit beschränkter Datenverfügbarkeit bietet diese Dissertation politischen Entscheidungsträgern mögliche Umsetzungsstrategien für lokale Stakeholder. Die entwickelten Modelle konnten Landnutzungsänderungen zuverlässig modellieren und Standorte identifizieren, an denen eine Einführung von bodenkonservierenden Maßnahmen notwendig ist, um eine Bodendegradation zu verhindern. Darüber hinaus können Modelle zur Einsparung von Kosten und Arbeitszeit bei Feldversuchen verwendet werden, sowie für die Bewertung des ökonomischen Nutzens oder von ökologischen Bedenken zu einer nachhaltigeren Landbewirtschaftung in abgelegenen und ländlichen Regionen beitragen

Participatory simulation of land-use changes in the northern mountains of Vietnam: the combined use of an agent-based model, a role-playing game, and a geographic information system

In Vietnam, the remarkable economic growth that resulted from the doi moi (renovation) reforms was based largely on the rural households that had become the new basic unit of agricultural production in the early 1990s. The technical, economic, and social changes that accompanied the decollectivization process transformed agricultural production, resource management, land use, and the institutions that defined access to resources and their distribution. Combined with the extreme biophysical, technical, and social heterogeneity encountered in the northern mountains, these rapid changes led to the extreme complexity of the agrarian dynamics that today challenges traditional diagnostic approaches. Since 1999, a participatory simulation method has been developed to disentangle the cause-and-effect relationships between the different driving forces and changes in land use observed at different scales. Several tools were combined to understand the interactions between human and natural systems, including a narrative conceptual model, an agent-based spatial computational model (ABM), a role-playing game, and a multiscale geographic information system (GIS). We synthesized into an ABM named SAMBA-GIS the knowledge generated from the above tools applied to a representative sample of research sites. The model takes explicitly into account the dynamic interactions among: (1) farmers¿ strategies, i.e., the individual decision-making process as a function of the farm¿s resource profile; (2) the institutions that define resource access and usage; and (3) changes in the biophysical and socioeconomic environment. The next step consisted of coupling the ABM with the GIS to extrapolate the application of local management rules to a whole landscape. Simulations are initialized using the layers of the GIS, e.g., land use in 1990, accessibility, soil characteristics, etc., and statistics available at the village level, e.g., population, ethnicity, livestock, etc. At each annual time step, the agrarian landscape changes according to the decisions made by agent-farmers about how to allocate resources such as labor force, capital, and land to different productive activities, e.g., crops, livestock, gathering of forest products, off-farm activities. The participatory simulations based on SAMBA-GIS helped identify villages with similar land-use change trajectories to which the same types of technical and/or institutional innovations could be applied. Scenarios of land-use changes were developed with local stakeholders to assess the potential impact of these changes on the natural resource base and on agricultural development. This adaptive approach was gradually refined through interactions between researchers and the local population

Sustainable Land Use and Rural Development in Southeast Asia: Innovations and Policies for Mountainous Areas

Sustainable Development; Landscape/Regional and Urban Planning; Agricultur

Biodiversity in rubber agroforests, carbon emissions, and rural livelihoods: An agent-based model of land-use dynamics in lowland Sumatra

AbstractRubber agroforests in the mostly deforested lowlands of Sumatra, Indonesia are threatened by conversion into monoculture rubber or oil palm plantations. We applied an agent-based model to explore the potential effectiveness of a payment for ecosystem services (PES) design through a biodiversity rich rubber eco-certification scheme. We integrated conditionality, where compliance with biodiversity performance indicators is prerequisite for awarding incentives. We compared a PES policy scenario to ‘business-as-usual’ and ‘subsidized land use change’ scenarios to explore potential trade-offs between ecosystem services delivery and rural income. Results indicated that a rubber agroforest eco-certification scheme could reduce carbon emissions and species loss better than alternative scenarios. However, the suggested premiums were too low to compete with income from other land uses. Nevertheless, integrating our understanding of household agent behavior through a spatially explicit and agent-specific assessment of the trade-offs can help refine the design of conservation initiatives such as PES

Simulating the impact of land use change and climate change on the supply of ecosystem services in a rubber-dominated watershed in Southwestern China

This cumulative PhD thesis investigates the expansion of rubber (Hevea brasiliensis Müll. Arg.) plantations and the ensuing multiple impacts on biodiversity and the supply of ecosystem services (ESS) in a mountainous watershed in Xishuangbanna Prefecture, Southwestern China. In recent decades, the study area, the Nabanhe Reserve, saw the expansion of rubber plantations and the loss of extensive forest areas, which led to a substantial decline in ESS. Workshops with regional stakeholders resulted in the development of three future land use scenarios for Nabanhe Reserve (2015 2040), varying in their degree of rubber expansions, management options and reforestations efforts. In the first study, the InVEST (Integrated Valuation of Ecosystem Services and Trade-offs) modeling framework was used to analyze the impact of these rubber expansion scenarios on selected ESS: sediment retention, water yield, habitat quality, and carbon sequestration. In addition, a model for assessing potential rubber yields was developed and implemented in ArcGIS. The analysis also included different statistical weighting methods to include rankings for the preference of ESS from three contrasting stakeholder groups (prefecture administration, tourists, off-site citizens). The study concludes that the integrated ESS indices would be overestimated without the inclusion of the stakeholder groups. The second study introduced a new method to identify potential tipping points in the supply of ESS. Here, time-series data derived from InVEST have been combined with a sequential, data-driven algorithm (R-method) to identify potential tipping points in the supply of ESS within two contrasting scenarios of rubber expansion in Nabanhe Reserve. The tipping point analysis included hydrological, agronomical, and climate-regulation ESS, as well as multiple facets of biodiversity. The model results showed regime shifts indicating potential tipping points, which were linked to abrupt changes in rubber yields, in both scenarios and at varying spatial scales. The study concludes that sophisticated land use planning may provide benefits in the supply of ESS at watershed scale, but that potential trade-offs at sub-watershed scales should not be neglected. The third study focused on modeling hydrological ESS (water yield and sediment export) in Nabanhe Reserve under multiple scenarios of land use and climate change in order to assess how both drivers influence the supply of these ESS. Three rubber expansion scenarios were analyzed in combination with multiple climate change scenarios using the InVEST modeling framework. Simulation results showed that the effect of land use and land management decisions on water yield in Nabanhe Reserve are relatively minor (4% difference in water yield between land use scenarios), when compared to the effects that future climate change will exert on water yield (up to 15% increase or 13% decrease in water yield compared to the baseline climate). Changes in sediment export were more sensitive to land use change (15% increase or 64% decrease) in comparison to the effects of climate change (up to 10% increase). The study concludes that in the future, particularly dry years may have a more pronounced effect on the water balance in Nabanhe Reserve as the higher potential evapotranspiration increases the probability for periods of water scarcity, especially in the dry season. In conclusion, the studies showed detrimental consequences induced by rubber expansions for all assessed ESS, with the exception of rubber yields. Further continuing the trend of rubber expansions in the study area is not the best option in terms of integrated ESS supply on a landscape scale. Land use planning alternatives, such as rubber expansions restricted to suitable areas only, in combination with reforestation efforts at less suitable locations, may be used to keep crucial environmental functions intact. Policy regulations at the local level, if properly assessed with spatial models and integrated stakeholder feedback, have the potential to buffer the typical trade-off between agricultural intensification and environmental protection. The implementation of these regulations might still pose a considerable challenge. The methods introduced in this Dissertation can easily be transferred to regions facing comparable land use situations, as InVEST and a large amount of the utilized spatial datasets are freely available.Die vorgelegte Doktorarbeit befasst sich mit der Ausweitung von Kautschukplantagen (Hevea brasiliensis Müll. Arg.) und den daraus folgenden vielfältigen Auswirkungen auf Biodiversität und die Bereitstellung von Ökosystemdienstleistungen (ÖSD) in einem bergigen Wassereinzugsgebiet in der Präfektur Xishuangbanna im Südwesten Chinas. In den vergangenen Jahrzehnten kam es im Untersuchungsgebiet, dem Nabanhe-Reservat, zu einer rasanten Ausweitung von Kautschukplantagen und dem Verlust weitläufiger Waldflächen und Ökosystemdienstleistungen. Aus Workshops mit regionalen Interessenvertretern entstanden drei Landnutzungsszenarien für die Zukunft des Nabanhe-Reservats (2015 2040), die sich hinsichtlich des Ausmaßes der Kautschukausweitung, verschiedener Managementoptionen und Wiederaufforstungsstrategien unterscheiden. In der ersten Fallstudie wurde das Model InVEST (Integrated Valuation of Ecosystem Services and Trade-Offs) verwendet, um die Auswirkungen der Landnutzungsszenarien auf vier ausgewählte ÖSD zu analysieren: Sedimentretention, Wasserertrag, Habitat-Qualität und Kohlenstoffbindung. Zusätzlich wurde ein Modell zur Abschätzung potenzieller Kautschukerträge entwickelt und in ArcGIS implementiert. Weiterhin wurden verschiedene statistische Gewichtungsmethoden benutzt, um die Präferenzen dreier kontrastierender Interessengruppen (Präfektur-Administration, Touristen, Externe Bürger) in der Auswertung der ÖSD Ergebnisse miteinzubinden. Die Studie kommt zu dem Schluss, dass die integrierten ÖSD Indizes ohne die Einbeziehung der Interessengruppen überbewertet würden. Die zweite Studie stellt eine neue Methode zur Identifikation potenzieller Kipp-Punkte (KP) in der Bereitstellung von ÖSD vor. Hierbei werden Zeitreihendaten von InVEST mit einem sequenziellen, datengetriebenen Algorithmus (R-Methode) kombiniert, um potenzielle KP in der Bereitstellung von ÖSD innerhalb zweier gegensätzlicher Landnutzungsszenarios abzuleiten. Die KP-Analyse umfasste hydrologische, agronomische und klimaregulierende ÖSD sowie mehrere Facetten der Artenvielfalt. Die Modellergebnisse zeigten in beiden Landnutzungsszenarien auf unterschiedlichen räumlichen Skalen Regimeverschiebungen, die auf potenzielle KP hindeuteten und aus abrupten Veränderungen der Kautschukerträge hervorgingen. Verbesserungen in der Bereitstellung von ÖSD können mit Hilfe von gut geplanten Landnutzungsstrategien auf der Skalenebene von Wassereinzugsgebieten erreicht werden. Potenzielle Trade-Offs auf kleineren Skalenebenen sollten jedoch auch beachtet werden. Die dritte Studie befasste sich mit der Modellierung hydrologischer ÖSD (Wasserertrag und Sedimentretention) im Nabanhe-Reservat unter verschiedenen Landnutzungs- und Klimawandelszenarien, um zu beurteilen, wie beide Faktoren die Bereitstellung dieser ÖSD beeinflussen. Drei Landnutzungsszenarien wurden in Kombination mit mehreren Klimawandel-Szenarien mit Hilfe von InVEST analysiert. Die Simulationsergebnisse zeigen, dass die Auswirkungen von Landnutzungs- und Landmanagemententscheidungen auf den Wasserertrag im Nabanhe-Reservat relativ gering sind (ein Unterschied von 4% im Wasserertrag zwischen den Landnutzungsszenarien), insbesondere wenn man sie mit den Auswirkungen des bevorstehenden Klimawandels vergleicht (eine 15% Zunahme oder 13% Abnahme des Wasserertrags verglichen mit dem Baseline-Klima). Sedimentexportwerte reagierten sensitiver auf Landnutzungsänderungen (15% Zunahme oder 64% Abnahme) im Vergleich zu den Auswirkungen des Klimawandels (bis zu 10% Zunahme). Die Studie kommt zu dem Schluss, dass sich in Zukunft besonders trockene Jahre stärker auf den Wasserhaushalt im Nabanhe-Reservat auswirken könnten, da die höhere potenzielle Evapotranspiration die Wahrscheinlichkeit für Zeiten der Wasserknappheit erhört, was insbesondere in der Trockenzeit eintreten könnte. Zusammenfassend zeigten die Studien nachteilige Folgen der Kautschukausweitung in Bezug auf alle betrachteten ÖSD mit Ausnahme der Kautschukerträge. Auf Landschaftsebene ist die zusätzliche Ausweitung von Kautschukflächen nicht die beste Option im Hinblick auf die integrierte ÖSD Bereitstellung. Alternativen der Landnutzungsplanung, wie z.B. die Kautschukausweitung auf geeignete Flächen zu beschränken und andere Flächen wieder aufzuforsten, können genutzt werden, um wichtige Umweltfunktionen zu erhalten. Politische Regelungen auf lokaler Ebene haben das Potenzial den typischen Zielkonflikt zwischen landwirtschaftlicher Intensivierung und Umweltschutz zu mildern, sofern sie mit räumlich expliziter Modellierung und dem Feedback von Interessengruppen ausgewertet werden. Die Umsetzung solcher Regelungen könnte jedoch eine beträchtliche Herausforderung darstellen. Die in dieser Dissertation vorgestellten Methoden können leicht auf Regionen mit vergleichbaren Landnutzungssituationen übertragen werden, da sowohl InVEST als auch der Großteil der verwendeten räumlichen Datensätze frei verfügbar sind

Integrated modelling for land use planning and policy recommendation in the Northern Uplands of Vietnam

The study focuses on analyses of major development problems related to livelihood and natural resource management in the Northern Uplands of Vietnam (NUV). The study was conducted in Suoi Con, a small agro-forestry watershed with the total area is about 1760 ha. The watershed is characterized by a high poverty rate and low agricultural production and household income. Livelihood of the households is dependent upon self-sufficient agricultural production, which accounts for nearly 80% of the total production value. Traditional agricultural activities have led to various land degradation problems. The main objective of the study is to integrate modeling of (i) erosion assessment, (ii) land use optimization and (iii) land use decision making in order to improve the effectiveness and adoption of recommendations that contribute to the improved livelihood of farmers and sustainable natural resource management. This will be achieved through: (1) increasing understanding of the interactions between agro-ecological and socio-economic dynamics at watershed scale; (2) facilitating emergence of a common agreement on ecological sustainability, social equity and economically sound solutions; and (3) stimulating dialogues among various stakeholders to achieve a shared responsibility of the common resources. The biophysical and socioeconomic characteristics of the study area were explored through surveys, FAO’s land evaluation, literature review and stakeholder meetings. The Predict and Localize Erosion and Runoff (PLER) model and the Revised Universal Soil Loss Equation (RUSLE) were used to examine influences of land use on soil erosion at the watershed scale.Although agricultural land in the watershed has several limitations such as steep slopes, low soil fertility, high acidity and serious soil erosion, different soil types and the large variation topography and crop suitability create flexibility in farmers’ land use decisions. The Land Use Planning and Analysis System (LUPAS) was then applied to analyze feasibilities of alternative land use options. Based on land use scenarios, 4 main land use constraints in the regions were analyzed. Results of the analysis were finally discussed with stakeholders though Role Playing Game sections to find feasible land use solution and to develop policy recommendations. Results of the study showed that different actors in the watershed have different views on land use targets, objectives, constraints and decisions. The integrated modeling approach used in this study identified that traditional technology level appears to be a largest constraint that significantly holds back agricultural production of the region. Land area, capital and labour are also constraints but they only appear if agricultural technology is improved. Land fragmentation should be considered as an important factor because without any new agricultural technique, crop variety or external capital, land consolidation can significantly improve food production and income. Integration of individual tools described in this study represents a participatory approach for land use planning, in which problems in land use are explicitly defined and land use plans are developed and revised by stakeholders under their own social and economic conditions. Imperfections in given land use plans and possible solutions proposed by stakeholders provide policy makers with ideas to improve land use planning and to bridge the gaps between land use objectives of the government and of farmers. The integrated modelling approach developed and presented in this thesis can make use of individual research tools for describing agro-ecological and socio-economic dynamics and for developing land use policy. It has the potential to serve planners and policy makers to increase the likelihood of developing plans that will effectively increase farmer livelihood and improve resource conservation. This integrated modelling approach can incorporate different aspects of land use into land use planning and test hypotheses regarding the contributions of intended plans to general development targets. Furthermore, it can support bottom-up land use planning as it allows incorporation of different stakeholders in analysing existing problems, proposing solutions and developing land use plans. Therefore, it can increase the likelihood of adoption. This in turn will create the chances for achievement of targets of the government, researchers and farmers through effective implementation of the plans.</p

Landscapes and livelihoods changes in the north-western uplands of Cambodia: Opportunities for building resilient farming systems

Almost 1 million hectares of forest lands have been reclaimed over the last 15 years for farming. Farmer practices with intensive mono-cropping based on tillage and herbicides use have resulted in significant soil erosion and rapid land degradation. Declining land productivity with increasing frequency of drought and flood have jeopardized the farm's economy of the smallholders. Understanding the impacts of land use changes on livelihoods and ecosystem services, and exploring intervention mechanisms based on Conservation Agriculture (CA) would help sustain smallscale farming systems in the Cambodian uplands. A research study on "Landscapes and livelihood changes in the northwestern uplands of Cambodia: Impacts on ecosystem services and opportunities for building resilient farming systems" is presented aiming to (i) analyze land use changes, their proximate causes, and underlying driving forces, (ii) assess the impacts of land use changes on local livelihoods and ecosystem services at multiple scales, (iii) evaluate the capacity of alternative cropping systems based on agro-ecology principles to preserve/restore soil fertility while improving local livelihoods, and (iv) assess the potential of conservation agriculture to enhance resilience of farming systems to climate change. The study produced (i) a full illustration of land use changes and its impacts provided by the integration of different scales: spatial, temporal, disciplinary, but also methods to describe and simulate changes, (ii) a new participatory approach adapted to the context of Cambodian uplands to develop the land use and landscape plan, and (iii) resilience scenarios of each type of farming system

The impact of swidden decline on livelihoods and ecosystem services in Southeast Asia: a review of the evidence from 1990 to 2015

Global economic change and policy interventions are driving transitions from long-fallow swidden (LFS) systems to alternative land uses in Southeast Asia’s uplands. This study presents a systematic review of how these transitions impact upon livelihoods and ecosystem services in the region. Over 17 000 studies published between 1950 and 2015 were narrowed, based on relevance and quality, to 93 studies for further analysis. Our analysis of land-use transitions from swidden to intensified cropping systems showed several outcomes: more households had increased overall income, but these benefits came at significant cost such as reductions of customary practice, socio-economic wellbeing, livelihood options, and staple yields. Examining the effects of transitions on soil properties revealed negative impacts on soil organic carbon, cation-exchange capacity, and aboveground carbon. Taken together, the proximate and underlying drivers of the transitions from LFS to alternative land uses, especially intensified perennial and annual cash cropping, led to significant declines in pre-existing livelihood security and the ecosystem services supporting this security. Our results suggest that policies imposing land-use transitions on upland farmers so as to improve livelihoods and environments have been misguided; in the context of varied land uses, swidden agriculture can support livelihoods and ecosystem services that will help buffer the impacts of climate change in Southeast AsiaThe authors wish to acknowledge the support of the Centre for International Forestry Research (CIFOR) via the award of an Evidence-Based Forestry grant administered on behalf of the UK Government’s Department for International Development (DfID) under the KNOW-FOR programme