Extinction risk of Mesoamerican crop wild relatives

Crop wild relatives (CWR) are the wild cousins of domesticated crops and an important source of genetic diversity that can help strengthen important food sources in the face of climate change and other threats. Mesoamerica is a significant centre of domestication, wild relative diversity and origin of many important crops, such as maize, squash, avocado, vanilla and cotton.

In this study, a stakeholder workshop selected 224 priority CWR taxa related to crops cultivated or domesticated in Mesoamerica and assessed their extinction risk according to IUCN Red List categories and criteria. Using occurrence data from GBIF and other sources, experts derived species distribution and richness maps, calculating the extent of occurrence (EOO) and area of occupancy (AOO) for each species of interest.

Among the assessed CWR taxa, 35 per cent were considered threatened including seven Critically Endangered (CR), 48 Endangered (EN) and 16 Vulnerable (VU). The crop with the highest proportion of threatened relatives was Vanilla at 100 per cent (eight taxa, all CR or EN), followed by cotton (Gossypium) with 92 per cent, avocado (Persea) with 60 per cent and maize with 44 and 33 per cent for Zea and Tripsacum, respectively.

The highest diversity of CWR taxa was located in the Mexican states of Jalisco (31 taxa) and Oaxaca (28 taxa), while most threatened taxa were present in Veracruz. The dominant threat processes included land use change introduced by agriculture and farming, pests and invasive alien species.

With climate change affecting existing crops and agricultural practices threatening CWR and the genetic potential they represent, the study highlights a need for promoting more sustainable agriculture and implementing policies supporting CWR conservation in Mesoamerica to help ensure future food security.