As few as nine crops account for two-thirds of the global food output, and on-farm crop diversity has declined significantly over the decades as farmers have switched from traditional production systems that utilise farmers’ varieties and landraces to modern production systems depending on officially released varieties, shows a report on global biodiversity of food and agriculture, released on Friday.

Globally, there are approximately 3,82,000 species of vascular plants, of which a little over 6,000 have been cultivated for food. Of these, as of 2014, fewer than 200 species had significant production levels globally, with only nine (sugarcane, maize, rice, wheat, potatoes, soyabeans, oil-palm fruit, sugar beet and cassava) accounting for over 66 per cent of all crop production by weight,” said the first-ever State of the World’s Biodiversity for Food and Agriculture report, released by the UN Food and Agriculture Organisation (FAO).

According to the report, which analysed country reports presented by 187 nations, the overall diversity present in farmers’ fields has declined and threats to diversity are increasing, even though the situation varies greatly depending on the country, location and type of production system.

“Although it is not possible to make definite statements about global trends, evidence suggests that overall, the diversity present in farmers’ fields has declined and that threats to diversity are getting stronger,” the report released in Rome said.

The biodiversity of food crops is important because it is the foundation of food systems and makes production systems more resilient and makes them withstand the effects of climate change.

However, it also added that since a widely applicable indicator for monitoring within-species diversity was still missing, the precise extent of such diversity is difficult to quantify.

Livestock

As regards livestock, the report said, the world’s livestock production is based on about 40 animal species, with only a handful providing the vast majority of global output of meat, milk and eggs.

As of 2018, 7,745 out of 8,803 reported livestock breeds were classified as local and 593 of these breeds are extinct. Among the extant local breeds, 26 per cent are considered to be at risk of extinction, while the risk status of 67 per cent is unknown. While wild water buffalo and banteng, jungle cattle present in South-East Asia, are classified as endangered, Indian bison, wild yak and wild goats are among vulnerable species.

“It appears that a higher proportion of livestock with wild relative species are threatened with extinction, rather than mammalian and bird species in general,” the report said.

Though 31,000 species of finfish, 52,000 species of aquatic molluscs, 64,000 species of aquatic crustaceans and 14,000 species of aquatic plants have been reported, global capture fisheries harvested in 2016 was limited to 1,800 marine species. The report, however, added that there are numerous genetically distinct stocks and phenotypes within these thousands of species.

Similarly, the data on inland fisheries could be incomplete as over half of all production is not designated by species, the reported said, quoting a scientific study in 2015.

As regards forest biodiversity, the FAO report said the number of tree species in the world is estimated to be around 60,000. Globally, more than 700 tree species, including bamboo, palms, and scrubs, have been included in tree-breeding programmes. It said forest resources are being threatened and eroded by conversion of forests to agriculture, unsustainable harvesting of trees for wood and non-wood products, grazing and browsing, climate change, forest fires and invasive species. Forests, according to the report, still cover 30.6 per cent of the world’s land area and even though forests continue to shrink, the rate of annual net loss of forests has decreased significantly over recent decades.

Among other things that threaten food and agriculture biodiversity, are the threat faced by pollinator species as well as a decline in soil decline. According to the report, one in seven species of vertebrate pollinators – such as bees – is threatened with global extinction (rising to almost one in three in island countries. Similarly, soil biodiversity is under threat in all regions of the world, leading to deterioration of soil health, it said.