For centuries, traditional farmers have developed diverse and locally adapted agricultural systems, managing them  with  ingenious  practices  that  often  result  in  both  community  food  security  and  the  conservation  of agrobiodiversity. This strategy of minimizing risk stabilizes yields, promotes dietary diversity, and maximizes returns using low levels of technology and limited resources. These microcosms of agricultural heritage still cover  no  less  than  10  million  ha  worldwide,  providing  cultural  and  ecological  services  not  only  to  rural inhabitants, but to mankind generally. These services include the preservation of traditional farming knowledge, local crop and animal varieties, and native forms of sociocultural organization. By studying these systems, ecologists can enhance their knowledge of the dynamics of complex systems, especially the relationship between biodiversity and ecosystem function and practical principles for the design of more sustainable agroecosystems  appropriate  to  small  farmers.  Novel  agroecosystem  designs  have  already  been  modeled  on successful traditional farming systems.