Climate Change, Plant Biodiversity, and Food Security: A Case Study from the AlUla Region of Saudi Arabia

AlUla, a hyper-arid oasis in north-western Saudi Arabia, exemplifies the critical interplay between plant biodiversity, climate change, and food security in dryland ecosystems. This chapter synthesizes ecological, ethnobotanical, and agronomic evidence to demonstrate how native and cultivated plant diversity underpins ecosystem services, traditional livelihoods, and climate resilience. Despite receiving less than 90 mm of annual rainfall, AlUla sustains over 60 native medicinal, forage, and wild edible species (Phoenix dactylifera, Moringa peregrina, Calligonum comosum), alongside cultivated fruit systems comprising more than 3.1 million date palms and 260,000 citrus trees. These biodiversity-rich agroecosystems enhance soil stability, microclimate regulation, pollination, and nutrient cycling functions increasingly threatened by rising temperatures, erratic precipitation, groundwater depletion, and land-use change. The chapter documents how traditional water management (qanat systems), multi-layered oasis agroforestry, and indigenous knowledge have historically buffered climatic extremes. However, ongoing climate warming (+0.4–0.6 °C per decade in the region) is accelerating habitat degradation, reducing forage availability, and altering the distribution of keystone species. Conservation and restoration initiatives led by the Royal Commission for AlUla (RCU) including native seed banks, protected areas (Sharaan Nature Reserve), and sustainable agriculture programs demonstrate a pathway to reconcile biodiversity conservation with food production. The chapter concludes that AlUla serves as a living laboratory for climate-resilient food systems, offering transferable lessons for arid lands globally. Aligning national strategies (Saudi Vision 2030) with international frameworks (CBD, SDGs) and community-based adaptation is essential to safeguard biodiversity as a foundation for long-term food security.