On-Farm Agrobiodiversity Index

The on-farm agrobiodiversity index applies the mathematics of biological diversity — richness, evenness, and combined indices such as Shannon, Simpson and Margalef — to the crops, landraces, varieties and livestock breeds that farmers actually maintain in their fields and herds. Rather than counting wild species in an ecosystem, it quantifies cultivated and reared diversity: how many distinct crop species and varieties a farm grows, how evenly the area or production is spread across them, and how this compares between farms, communities and regions. Devra Jarvis and a large international team showed in 2008 that these measures of richness, evenness and divergence reveal substantial crop-variety diversity still maintained on farms worldwide and provide a sound basis for indicators of on-farm conservation. Built on Magurran's standard diversity formulas, the index turns agrobiodiversity into measurable, comparable numbers for research and policy.