Global change impacts on cacti (Cactaceae): current threats, challenges and conservation solutions.

This article reviews the major global change threats to cacti (family Cactaceae) distributed across arid to semi-arid subtropical regions of the Americas, focusing on four key factors: rising atmospheric CO₂ concentrations, increasing temperatures and heat waves, intensified droughts, and enhanced competition and wildfire frequency due to invasive non-native species. It examines how morphological and physiological traits—such as stem volume-to-surface area ratios, rooting depths, thermal tolerance mechanisms, and variations in crassulacean acid metabolism (CAM) photosynthesis—may influence species' resilience or vulnerability to these stressors. The review highlights the critical conservation challenges facing cacti, including habitat loss, illegal collection, and altered fire regimes, and proposes integrated strategies involving international cooperation, habitat restoration, management of invasive grasses, protection of nurse plants, ex situ conservation, and forensic tools to combat illegal trade. The article underscores the complexity of predicting climate change impacts on cacti due to their diverse adaptations and distributions, emphasizing the need for coordinated monitoring and innovative conservation approaches.