Final answer:
Planting traditional local species of edible plants is the practice that helps maintain food diversity, contributing to the biodiversity and resilience of food systems.
Step-by-step explanation:
The practice that helps to maintain food diversity is planting traditional local species of edible plants. This approach preserves the genetic diversity of crops, which is vital for ensuring a resilient and sustainable food supply. Using traditional varieties can contribute to the overall biodiversity, supporting ecosystems and the range of pollinators, extending the usable land for different crops, and potentially improving disease and pest resistance through natural means. By contrast, increased use of genetically modified crops can lead to genetic homogeneity, and replacing food crops with cash crops can reduce crop diversity.
Furthermore, sustainable farming techniques that follow traditional practices like agroforestry and crop rotation foster higher food yields, healthier soils, and reduced use of fertilizers and pesticides. The biodiversity found within these systems helps in conserving numerous species and contributes to the long-term viability of our food systems.