only found in the natural science databases, with 13% only in social science database, and 5% only in economic literature. No references were in the databases from all three fields of science. The remaining references were found in two out of the three fields, with 2% in social and natural sciences, none in social sciences and economics, and 16% in a combination between natural sciences and economics (Fig. 2).Compared to the total number of references in the searched databases, relatively few referred to agroecology. For example CAB (2001) refers to 1195 abstracts including the term agroecology out of the more than 2 million references in total. In comparison, more than 300,000 references referred to animal nutrition. Using the definition of agroecology stated in the next section, we could have redefined a number of additional and often earlier studies as agroecological, even though the authors chose not to describe them as such at the time. However, the point of the survey was not to determine what work was being done but rather whether the scientists involved considered the studies to be agroecological.2.4. A definition of agroecologyIn this paper, agroecology is defined as "the study of the interactions between plants, animals, humans and the environment within agricultural systems". Agroecology as a discipline therefore covers integrative studies within agronomy, ecology, sociology and economics (Fig. 1). Most authors acknowledge agroecology as a discipline of integration, but define it in other terms, for example as 'the application of ecological science to design and management of sustainable agroecosystems' (Gliessman, 1998). Thereby, the upper part of the window of agroecology in Fig. 1 is excluded. Clearly there is still not one, finally acknowledged definition of agroecology, indicating the ongoing development within the discipline.The historical development of agroecology shows that it began originally as a part of crop physiology, agricultural zoology, and ecology but the term was adopted by a movement which wished to promote the development of sustainable agriculture through the integration of ideas and methods from other disciplines (Altieri, 1980). Now agroecology departments exist at a number of universities across the world but particularly in the USA and Europe. This implies that at least some people think that agroecology has made the transition from a proposition to a separate scientific discipline. In the next section, the case for considering agroecology as a separate scientific discipline is examined.3. Agroecology as a separate, scientific discipline3.1. A separate disciplineTo be considered a separate discipline, agroecology must be distinguishable from existing disciplines. The argument is that agroecology is distinguished from its parental disciplines of agronomy, ecology and socio-economics by its integration between these disciplines and across scales. The agroecology-related studies found in the literature survey were characterised by an integrative approach, where information from single disciplines was collected and combined to solve problems at a higher scale. An additional indication that agroecology is a separate discipline is that the numbers of references to agroecology have increased in recent years, indicating that more scientists feel that their work lies sufficiently far from the existing scientific disciplines that an alternative term is necessary.3.2. A