The most prominent social effect of transitioning from older forms and models of food production to the dominant industrial form is the destruction of diverse existing rural cultures. These cultures are what put the “culture” in agriculture, making it something specific to certain peoples, regions, and ecologies.
The term “agro-biodiversity” describes how these cultures’ diverse ways of growing food also helps to develop and maintain biodiversity. This biodiversity includes the distinct breeds and varieties grown as foods and the genetic diversity maintained within these varieties, but also beings in the ecosystem whose survival is benefitted by (and benefits) ecological farming systems. This latter component includes plants and animals that are not directly or intentionally supported by the act of farming: wildlife that are provided greater access to food, habitat, nesting ground, and protection by landscapes cultivated and managed in ecological ways.
Many specific vegetables, medicinal herbs, and particularly rare grain species have been maintained and reproduced over long periods by groups of people due to their cultural/culinary importance. Grains, herbs, trees, and even semi-wild animals have been cultivated and domesticated by small subsets of the human population. Without this continual work (what’s called “in-situ conservation” because it happens in place), these species are at risk of dying out. In contrast to the efforts by large institutions to do “ex-situ” conservation of genetic material diversity (mainly by maintaining large stores of seeds in frozen “seed banks”), agro-biodiversity raises the importance of the people who are key parts of any food crop’s ecosystem.
The real tragedy, then, is not just that monocultural agriculture creates monocultural cultures (think of the “McDonaldization” of much of the world’s food habits). The destruction of existing rural cultures also reduces the material from which new more sustainable agricultures can be created: the seed diversity that might hold adaptive responses to climate change, the plant diversity that can maintain and improve a nutritious diet, or the animal diversity that can keep functioning ecosystems functioning. It’s both an environmental and a social loss, wrapped into one.