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Publications - Economics

Rasch, S., et al., (2017), Multi-scale resilience of a communal rangeland system in South Africa, Ecological Economics, 131: 129-138

Resilience has either been assessed on system or individual scale so far. Ignoring the other scale may potentially change the interpretation of resilience in socio-ecological systems (SES). Thus, this paper argues that the co-evolution of both resiliencies must be studied to capture multi-scale complexity. We attempt to close this gap by assessing resilience at both scales of a village community in Thaba Nchu, South Africa. Villagers use a commonly managed rangeland for beef cattle production. An agent based model of household interaction coupled with a biophysical model of the rangeland measures the resiliencies of the SES towards a shock, a stress and a policy intervention. Currently, the SES remains in a stable attractor in terms of SES resilience. Household resilience, however, degrades in a process of structural change. A drought scenario shows improved SES resilience but structural change at household level accelerated. An increase in the number absentee herders increases the likelihood for SES collapse by eroding social embededdness. Finally, an introduced basic income grant demonstrates that the SES is able to cope with an increased number of appropriators. However, interaction of the policy intervention with an exogenous stress translates into an increased probability of SES decoupling.

Willy, K.D. and Kuhn, A., (2016): Technology Adoption Under Variable Weather Conditions — The Case of Rain Water Harvesting in Lake Naivasha Basin, Kenya, Water Economics and Policy, 2(2): online

This paper applies a parametric econometric duration model (log–logistic) to analyze the duration of adoption of rain water harvesting techniques (RWHTs) among smallholder farmers in the Lake Naivasha basin, Kenya. The study utilizes survey data from 307 farm-households who are dependent on rain-fed agriculture in a region where rainfall has historically been relatively variable. In such circumstances, RWHT helps to stabilize water supply and help farmers manage weather-related risks. The current study seeks to identify constraints to the spread of RWHTs by exploring how rainfall variability influences the timing of decisions to adopt RWHTs alongside other farm-household and spatial characteristics. Empirical results indicate that although rainfall variability is a significant determinant of time to adoption of RWHTs, farmers’ sensitivity to rainfall variability have declined over time. Instead, access to informal sources of information has gained importance in adoption of RWHT implying that adoption has become more of an endogenous process of social exchange within communities, and less driven by external natural pressure and persuasion by state agents. Other important factors were: age and education level of household head, domestic water demand, ground water abstraction and the number of previous and expected adopters in the village.


Linstädter, A., et al. (2016), Assessing the resilience of a real-world social-ecological system: lessons from a multidisciplinary evaluation of a South African pastoral system, Ecology and Society 21 (3):35

In the past decades, social-ecological systems (SESs) worldwide have undergone dramatic transformations with often detrimental consequences for livelihoods. Although resilience thinking offers promising conceptual frameworks to understand SES transformations, empirical resilience assessments of real-world SESs are still rare because SES complexity requires integrating knowledge, theories, and approaches from different disciplines. Taking up this challenge, we empirically assess the resilience of a South African pastoral SES to drought using various methods from natural and social sciences. In the ecological subsystem, we analyze rangelands’ ability to buffer drought effects on forage provision, using soil and vegetation indicators. In the social subsystem, we assess households’ and communities’ capacities to mitigate drought effects, applying agronomic and institutional indicators and benchmarking against practices and institutions in traditional pastoral SESs. Our results indicate that a decoupling of livelihoods from livestock-generated income was initiated by government interventions in the 1930s. In the post-apartheid phase, minimum-input strategies of herd management were adopted, leading to a recovery of rangeland vegetation due to unintentionally reduced stocking densities. Because current livelihood security is mainly based on external monetary resources (pensions, child grants, and disability grants), household resilience to drought is higher than in historical phases. Our study is one of the first to use a truly multidisciplinary resilience assessment. Conflicting results from partial assessments underline that measuring narrow indicator sets may impede a deeper understanding of SES transformations. The results also imply that the resilience of contemporary, open SESs cannot be explained by an inward-looking approach because essential connections and drivers at other scales have become relevant in the globalized world. Our study thus has helped to identify pitfalls in empirical resilience assessment and to improve the conceptualization of SES dynamics.

Kuhn, A., et al., (2016), Simulating the viability of water institutions under volatile rainfall conditions - The case of the lake Naivasha Basin, Environmental Modelling & Software, 75: 373-387

This study views the Lake Naivasha Basin in Kenya's Rift Valley as a hydro-economic system with slowly emerging basin-wide water management institutions. Possible institutions face two interlinked challenges. Firstly, large scale horticultural activities as a core economic activity in the basin require substantial and regular amounts of irrigation water, abstracted from the lake and its aquifer. The lake level and thus irrigation water availability reveal a falling trend over the last two decades, which calls for institutions aimed at restricting further expansion in water use. Secondly, the region is characterized by volatile weather conditions where periods of average and above average rainfall have alternated with prolonged droughts for centuries. That leads to highly volatile water inflows into the lake. The two challenges combined thus call for water management institutions that support sustainable water use in both the short and the long run. This study therefore investigates the effect of water institutions already existing or proposed by local stakeholder organizations on preserving target lake levels against a background of highly volatile water availability which negatively affects the economic viability of institutions. To take the absence of functioning basin-wide coordination mechanisms for water allocation into account, we employ the solution format of Multiple Optimization Problems with Equilibrium Constraints (MOPEC) in our integrated hydro-economic model. Stochastic scenario simulations with the model reveal that compliance to water regulations and thus the viability of water institutions in the Naivasha Basin would require very high penalties which are not likely to be accepted by users.

Rasch, S., et al., (2016a), Cooperation and Collapse in a communual livestock production SES model - a case from South Africa, Environmental Modelling & Software, 75: 402-413

Institutional arrangements are considered necessary for successfully governing the commons. They are furthermore thought to be more effective if they are self-organized instead of being imposed. However, endogenous institutional arrangements, like local norms, are specific to a particular socio-ecological systems (SES). This paper presents a SES model of communal livestock producers in South Africa. Its bio-physical component accounts for the impact of biotic and abiotic factors on livestock population. The social agent based component models individual and socially determined behaviour, the latter being a social norm specific to the case. Model results show that cooperative agents obeying and sanctioning the norm reduces the likelihood of SES collapse in terms of livestock population crashes. However, cooperation among agents only emerges in times of ecological crisis where social reorganization is fostered. The crisis creates the opportunity for initializing a self-enforcing process of mutual cooperation. Model specifications are based on survey data and agents were parameterized according to individual household data. A sensitivity analysis shows that this empirical heterogeneity cannot be reduced without changing model outcomes.

Rasch, S, et al., (2016b), Reorganizing resource use in a communal livestock production socio-ecological system in South Africa, Land Use Policy, 52: 221-231

Livestock production on South Africa’s commons contributes significantly to the livelihoods of communal households, offering status, food, income and savings. Management innovations are generally top-down and informed by commercial practices such as rotational grazing in combination with conservative stocking. Implementations often ignore how the specific socio-ecological context affects outcomes and the impact on equity. Science now acknowledges that rangeland management must be context specific and that a universally agreed-upon recommendation for managing semi-arid rangelands does not exist. We present a socio-ecological simulation model derived from a case study in South Africa and use it to assess the socio-ecological effects of rotational vs. continuous grazing under conservative and opportunistic stocking rates. We find that continuous grazing under conservative stocking rates leads to the most favourable outcomes from the social and the ecological perspectives. However, the past legacy under apartheid and participants’ expectations renders its successful application unlikely because enforceability is not ensured.

Willy, D.K., et al., (2014), Estimating the joint effect of multiple soil conservation practices: A case study of smallholder farmers in the Lake Naivasha basin, Kenya, Land Use Policy, 39: 177-187

The current study seeks to assess the private benefits associated with multiple soil conservation practices (MSCPs) by estimating the marginal value of crop production that can be attributed to such practices. In areas where land degradation associated with soil erosion causes serious agri-environmental challenges such as loss of soil fertility, siltation and eutrophication, a multiple approach to soil conservation is neccessary. However, notwithstanding efforts to encourage adoption of such practices, their uptake remains generally low. Analysing the effect of MSCPs on crop productivity is one of the ways through which the incentives for soil conservation can be explored. To achieve the stated objective, the current study applied propensity score matching and exogenous switching regression techniques to cross-sectional data collected from a random sample of farm households located in Lake Naivasha basin, Kenya. Results indicate that there is a significant positive effect of implementing multiple soil conservation practices on crop productivity. However, we note that whether the additional benefits will cover the opportunity costs associated with the implementation of these practices will depend on farm specific attributes such as slope and the soil conservation effort. In cases where marginal benefits are not substantial to cover opportunity costs for implementation of soil conservation practices, intrinsic or external incentives could be necessary. Policy interventions could focus on offering technical assistance to farmers in selecting soil conservation practices that are best suited to their local condition.

 

Britz, W., et al., (2013), Modeling water allocating institutions based on Multiple Optimization Problems with Equilibrium Constraints, Environmental Modelling & Software, 46 (0), 196-207

Hydro-economic river basin models (HERBM) based on mathematical programming are conventionally formulated as explicit ‘aggregate optimization’ problems with a single, aggregate objective function. Often unintended, this format implicitly assumes that decisions on water allocation are made via central planning or functioning markets such as to maximize social welfare. In the absence of perfect water markets, however, individually optimal decisions by water users will differ from the social optimum. Classical aggregate HERBMs cannot simulate that situation and thus might be unable to describe existing institutions governing access to water and produce biased results for alternative ones. We propose a new solution format for HERBMs, based on Multiple Optimization Problems with Equilibrium Constraints (MOPEC), which allows, inter alia, to express spatial externalities resulting from asymmetric access to water use. This new problem format, as opposed to commonly used linear (LP) or non-linear programming (NLP) approaches, enables the simultaneous simulation of numerous ‘independent optimization’ decisions by multiple water users while maintaining physical interdependences based on water use and flow in the river basin. We show that the alternative problem format allows formulating HERBMs that yield more realistic results when comparing different water management institutions.

Willy, D.K. and Holm-Müller, K., (2013): Social influence and collective action effects on farm level soil conservation effort in rural Kenya, Ecological Economics, 90: 94-103

This paper analyzes the effects of social influence and participation in collective action initiatives on soil conservation effort among smallholder farmers in Lake Naivasha basin, Kenya. We apply binary and ordered probit models in a two stage regression procedure to cross-sectional data collected through a household survey among randomly selected smallholder farmers. Smallholder farming systems in the research area are associated with practices that render farmlands susceptible to soil erosion causing negative impacts on land and the environment. Therefore, strategies that encourage soil conservation are likely to also offer solutions for dealing with agri-environmental challenges and poverty alleviation. Results indicate that social capital facilitates participation in collective action initiatives which then influence individual soil conservation efforts. Neighborhood social influences, subjective norms, gender, education level, farm size, access to credit and livestock ownership also emerge as key determinants of soil conservation effort. Policy implications drawn by this study encourage strategies to increase participation and effectiveness in collective action initiatives as a boost to soil conservation. Implementation of soil conservation practices could also be encouraged through awareness increasing instruments, facilitating access to agricultural micro-credit and paying attention to gender related challenges on knowledge access and rights over land and other natural resources.

 

Kuhn, A., Britz, W. (2012), Can hydro-economic river basin models simulate water shadow prices under asymetric access?, Water Science & Technology, 66 (4), pp. 879-886

Hydro-economic river basin models (HERBM) based on mathematical programming are conventionally formulated as explicit ‘aggregate optimization’ problems with a single, aggregateobjective function. Often unintended, this format implicitly assumes that decisions on water allocation are made via central planning or functioning markets such as to maximize social welfare. In the absence of perfect water markets, however, individually optimal decisions by water users will differ from the social optimum. Classical aggregate HERBMs cannot simulate that situation and thus might be unable to describe existing institutions governing access to water and might produce biased results for alternative ones. We propose a new solution format for HERBMs, based on the format of the mixed complementarity problem (MCP), where modified shadow price relations express spatial externalities resulting from asymmetric access to water use. This new problem format, as opposed to commonly used linear (LP) or non-linear programming (NLP) approaches, enables the simultaneous simulation of numerous ‘independent optimization’ decisions by multiple water users while maintaining physical interdependences based on water use and flow in the river basin. We show that the alternative problem format allows the formulation HERBMs that yield more realistic results when comparing different water management institutions.

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