A resilience approach to sustainability focuses on how to build capacity to deal with unexpected change. This approach moves beyond viewing people as external drivers of ecosystem dynamics and rather looks at how we are part of and interact with the biosphere – the sphere of air, water and land that surrounds the planet and in which all life is found. One of the main ways in which people depend on and interact with the biosphere is through their use of different ecosystem services, such as the water we use for cooking and drinking, the crops we grow to nourish ourselves, regulation of the climate and our spiritual or cultural connections to ecosystems. People also change the biosphere in many ways through activities such as agriculture, and building roads and cities. A resilience thinking approach tries to investigate how these interacting systems of people and nature – or social-ecological systems – can best be managed to ensure a sustainable and resilient supply of the essential ecosystem services on which humanity depends.
Small-scale farmers often plant several different food crops so that failure of any one crop will not have catastrophic impacts on food provision. Similarly, natural resource harvesting systems, which target a number of different species, are more resilient than systems which target single species. Evidence from several other fields of study suggests that systems with many different components are generally more resilient than systems with few components. Functional redundancy, or the presence of multiple components that can perform the same function, can provide ‘insurance’ within a system by allowing some components to compensate for the loss or failure of others. In short, redundancy is embodied in the saying “don’t put all your eggs in one basket”.
Redundancy is even more valuable if the components providing it also react differently to change and disturbance. This is what we call response diversity (differences in the size or scale of the components performing a particular function give them different strengths and weaknesses, so that a particular disturbance is unlikely to present the same risk to all components at once). For example, seed dispersal in Ugandan forests is performed by a range of different-sized mammals, from mice to chimpanzees. While the small mammals are negatively affected by local disturbances, the larger, more mobile species are not and can therefore maintain their function as seed dispersers.
Within a governance system, a variety of organisational forms such as government departments, NGOs and community groups can overlap in function and provide a diversity of responses, because organisations with different sizes, cultures, funding mechanisms and internal structures are likely to respond differently to economic and political changes. Diverse groups of actors with different roles are critical in the resilience of social-ecological systems, as they provide overlapping functions with different strengths. In a well-connected community, where functions overlap and redundancy is present, creativity and adaptability can flourish.
Conventional economic thinking promotes maximum efficiency, while resilience thinking encourages policies that can better cope with ecological, market or conflict-related shocks. For example, in farming communities, livelihood options that are dissimilar to farming, such as a tourism-related activities rather than alternative types of farming, will provide greater response diversity and thus resilience to shocks. Specific incentives can be created to encourage such diversification at the individual farmer level.