Agriculture and Agri-Food Canada defines an “agroecosystem” as an “ecosystem under agricultural management — an open dynamic system connected to other ecosystems through the transfer of energy and materials.” While the importance for agriculture of such natural resources as soil, water, and air has long been recognized, the agroecosystem approach puts biological resources at the center of agricultural concerns. Issues related to biological diversity in sustainable agroecosystems and their implications, with a particular focus on the impact of biotechnologies are discussed.