Distribution of pollination and biological control studies relevant to food production used in quantitative reviews. Smallholding Environment (coloured areas) is a broad classification of smallholding type (see  for definitions) for countries that are not defined as OECD-high income nations (greyed areas) by the World Bank. These colours state the likely type of smallholding to be found if present and do not reflect the presence/absence or importance of smallholding in an area. High potential environments (in terms of crop yield) are a combination of irrigated farming systems, wetland rice-based farming systems, and rain-fed farming systems in humid areas of high resource potential. Low potential environments are those of low current productivity or potential because of extreme aridity or cold. Highland environments are steep, highland areas.