Universität zu Köln

Martin, Romina (2013). Livelihood security of pastoralists in semi-arid rangelands under global change - A social-ecological modelling study. PhD thesis, Universität zu Köln.

Preview

PDF Dissertation_RMartin2013.pdf - Published Version Download (8MB)

Abstract

More than two billion people inhabit global drylands where animal husbandry is the most important source of income for pastoral livelihoods. Consequences of climate and land use change accompanied by human population growth cause an accelerating degradation of natural resources. These trends endanger sustainable range management for livestock and consequentially pastoral livelihood security. Drylands are characterized by low and spatio-temporally variable precipitation. It follows, that sustainable range management is dependent on adaptive mobility to make use of the highly variable availability of forage resources. Intensive research on such strategies is mainly focused either on ecological or economic aspects of sustainable resource use. However, the feedbacks between the natural and the social system are currently not well understood so far. It is still an open question how the diverse set of drivers interacts and translates into vulnerability for pastoral livelihoods. We aim to analyze the consequences of climate and land use change on pastoral livelihood security. This is exemplified by a case study on nomadic herdsmen in the High Atlas Mountains of Southern Morocco. The challenge is to evaluate diverse aspects of pastoralism and their combined impact on pastoral households. To achieve this goal, we develop an ecological-economic simulation model on spatially heterogeneous rangelands. The resulting herd size dynamics are then evaluated by means of an innovative risk assessment, to identify the constraints under which income for households is not sufficient anymore in three different model applications. First, consequences of projected climate change for drylands are investigated in terms of increased precipitation variability and decreased mean annual precipitation. Interestingly, increasing precipitation variability has a smaller effect on the sustenance of the herd size than for example a decreased mobility. Especially the negative effects of extremely high precipitation variability were not confirmed by this study. This can be partly explained by the traits of perennial vegetation. Mediterranean shrubs are able to conserve reserves that buffer effects of variable precipitation and production of forage. But even more important is the adaptive strategy of mobile and frequently destocked herds, which allows sufficient pasture resting and thereby a sufficient performance of vegetation and herd size. The second model application tests the effect of drought events on pastoral livelihood security. Surprisingly, meteorological droughts are only in rare cases the single cause for the vulnerability of pastoral households since several effects overlap. This is proved by a hypothetical reference simulation under constant precipitation, where a considerably high variation of vegetation and herd size can be observed. This is evidence for a tightly coupled vegetation-herbivore system which already poses a challenge for pastoral livelihoods. The innovative characterization of diverse socio-economic household types reveals the major influence of socio-economic factors compared to single drought events on the livelihood of mobile pastoralists. The third model application uses a newly developed operationalization of the concept of key resources to evaluate the relative importance of different pasture types for local herds in the High Atlas Mountains of Morocco. These pastures are characterized by specific vegetation traits due to the climatic gradient and different tenure regimes. Particularly, the communal winter pastures can be identified as essential for the long term sustenance of livestock. Besides vegetation production, the ability to conserve reserves plays an important role. This applied example helps to review and refine the concept of key resources. The different applications of our newly developed model help to find options and constraints of sustainable range management related to the combined effect of natural and socio-economic impacts. Model analyses enable us to compare climate and socio-economic change in their consequences on pastoral livelihood security. Notably, it seems that climate change affects adaptive herd management less then previously expected. This underlines the importance of typical traits of adaptive pastoralism for sustainable resource use. A major risk for livelihoods is posed by socio-economic change such as increasing income needs or reduced mobility resulting from land use change. This could partly be compensated by increasingly diversified income from non-pastoral activities but it remains an open question how effective this strategy is in the long-term. The general principles of sustainable range management can be further demonstrated by the development of a strategic board game. In it, three to five players take the role of nomadic herdsmen to raise their herd of sheep. During the game, players can experience typical events in the environment of pastoral households and are confronted with complex decisions. The board game supports the communication and education about various aspects of sustainable range management, such as mobility and resting times for pastures. Beyond that, it facilitates learning about natural resource use and livelihood security in a broadly understandable way. Finally, the problem-oriented modelling approach of this work contributes to the integration of natural and social sciences in research on range management in drylands. The interdisciplinary perspective supports mutual understanding on principles of sustainable land use which could be transfered to wider regions.