Agroecology advocates maximising diversity. From a biological point of view, this diversity of species and genetic resources can be maintained at a spatial level (agroforestry systems and intercropping) or temporal level (crop succession) and by the effective combination of plants and animals. Biodiversity contributes to the maintenance of nutritional wealth; to productivity, creation of new market opportunities, product variety, and consequently income; security against the risks of climate change in agricultural production; greater capacity for efficient use of environmental resources, in addition to performing ecosystem services such as pollination and maintenance of soil quality. Diversified agroecological systems are more resilient, with a more remarkable ability to recover from disturbances, including extreme weather events such as droughts, floods, or hurricanes, and to withstand the onslaught of pests and diseases. Agroecological approaches can also increase socio-economic resilience. Through diversification and integration, producers reduce their vulnerability if a single crop, animal species, or other commodity fails. By reducing dependence on external inputs, agroecology can reduce producers' vulnerability to economic risk.