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