One of the salient features of GIAHS is their high degree of biodiversity. This diversity occurs at various scales from plant and animal genetic resources to landscapes.  By planting several species and varieties of crops farmers minimize the risk of catastrophic loss, stabilize yields over the long term, and maximize returns even with low levels of technology and limited resources. This strategy, moreover, promotes dietary diversity. Many of these plants cultivated by local farmers are landraces grown from seed which has been passed down from generation to generation and selected over the years to produce desired production characteristics. Landraces are genetically more heterogeneous than modern cultivars and can offer a variety of defenses against vulnerability. The same holds true for local animal breeds, which have been domesticated and developed over centuries to meet local environmental and social requirements.

Such biodiverse agricultural systems are also endowed with nutrient-enriching plants, insect predators, pollinators, nitrogen-fixing and nitrogen-decomposing bacteria, and a variety of other organisms that perform various beneficial ecological functions. Additionally, many such agro-ecosystems provide habitats to wildlife, including endangered wildlife species.

Clearly, traditional agricultural production commonly encompasses the multiple uses of both natural and artificial ecosystems, where crop production plots and adjacent habitats are integrated into a single agroecosystem.

The use of traditional farming practices with minimal industrial inputs has resulted in a varied, highly heterogeneous landscape - possibly even more heterogeneous than would exist naturally. In fact, the crop and livestock production units and adjacent habitats constitute a continuum where plant gathering, fishing, animal and crop production are actively undertaken.

These complex agroecosystems and their agricultural biodiversity and associated landscapes can, therefore, only be conserved and managed sustainably with a holistic approach, involving all stakeholders and building on local people's knowledge and experience. The dynamic conservation of GIAHS is vital to the future of humankind, and should be treated at the international level as an ecological/cultural resource of utmost global significance.