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This paper reviews the determinants of rural household food security in Africa and Asia where more than 88% of the world's undernourished people live. A conceptual model is proposed on the basis of the three widely known components of food security: food availability, accessibility and utilisation. This model is used to select a total of 40 peer-reviewed studies carried out over the last decade (20 each from Africa and Asia). A meta-analysis technique is then used to identify which determinants of food security have been highlighted and how well the causality is demonstrated. Food availability is the most studied component in both regions, followed by food accessibility, while food utilisation is the most neglected component in these studies.

Building on available theory, this work uses controlled laboratory experiments to investigate the budgetary and the economic performance of competitive tenders for allocating conservation contracts to landholders. Experiments have been replicated in two different countries to check for robustness of results. We find that auctions outperform the more traditional fixed-price programs only in the one-shot setting. With repetition, the auctions quickly lose their edge. The budget-constrained auction performs similarly to the targetconstrained in the one-shot setting but appears more robust to repetition. Our results suggest that previous estimates of conservation auction performance are too optimistic, and we propose a method for improving such estimates.

Conservation tenders are being used as a policy mechanism to deliver environmental benefits through changes in land, water and biodiversity management. While these mechanisms can potentially be more efficient than other agri-environmental and payment for ecosystem service schemes, a key limitation in practice is that participation rates from eligible landholders are often low, limiting both efficiency and effectiveness. In this paper we document and review potential causes of low participation in two categories: those that treat participation as an adoption issue focused on searching for the landholder, farm or practice characteristics that limit participation; and those that treat it as an auction design issue, looking for the different auction, contract or transaction cost elements that limit landholder interest in participation. We then model how landholders make choices to engage and bid in a tender, making three important contributions to the literature on this topic. First, we document the low participation rates in conservation tenders, mostly across developed countries, an issue that has received little attention to date. Second, we explain that a decision to participate in a conservation tender involves three simultaneous decisions about whether to change a management practice, whether to be involved in a public or private program with contractual obligations, and how to set a price or bid. Third, we explain that there are a number of factors that affect each stage of the decision process with some, such as landholder attitudes and risk considerations, relevant to all three. Our findings suggest that decisions to participate in a conservation tender are more complex than simple adoption decisions, involving optimisation challenges over a number of potentially offsetting factors.

Marine fish stocks are in many cases extracted above sustainable levels, but they may be protected through restricted-use zoning systems. The effectiveness of these systems typically depends on support from coastal fishing communities. High management costs including those of enforcement may, however, deter fishers from supporting marine management. We incorporated enforcement costs into a spatial optimization model that identified how conservation targets can be met while maximizing fishers' revenue. Our model identified the optimal allocation of the study area among different zones: no-take, territorial user rights for fisheries (TURFs), or open access. The analysis demonstrated that enforcing no-take and TURF zones incurs a cost, but results in higher species abundance by preventing poaching and overfishing. We analyzed how different enforcement scenarios affected fishers' revenue. Fisher revenue was approximately 50% higher when territorial user rights were enforced than when they were not. The model preferentially allocated area to the enforced-TURF zone over other zones, demonstrating that the financial benefits of enforcement (derived from higher species abundance) exceeded the costs. These findings were robust to increases in enforcement costs but sensitive to changes in species' market price. We also found that revenue under the existing zoning regime in the study area was 13-30% lower than under an optimal solution. Our results highlight the importance of accounting for both the benefits and costs of enforcement in marine conservation, particularly when incurred by fishers.