Elevated extinction risk of cacti under climate change

Area of Science:

• Ecology
• Botany
• Conservation Biology

Background:

• Cactaceae (cacti) are a highly endangered plant family from the New World.
• Conservation planning is hindered by uncertainty regarding climate and land-use change impacts on cactus diversity.
• While some cacti are adapted to arid conditions, many species inhabit cooler, mesic ecosystems, questioning their tolerance to future warming and drought.

Purpose of the Study:

• To assess the hypothesis that cacti will benefit and expand their distribution in a warmer, more drought-prone world.
• To quantify the exposure of cactus species to climate change through range forecasts.
• To evaluate the impact of climate change on global cactus diversity and identify species at risk.

Main Methods:

• Range forecasts and diversity maps were generated for 408 cactus species.
• Analyses considered three Representative Concentration Pathways (2.6, 4.5, and 8.5) for 2050 and 2070.
• The study assessed factors influencing future climate suitability, including dispersal ability and model complexity.

Main Results:

• 60% of cactus species are projected to experience a reduction in favorable climate conditions.
• Approximately 25% of species may face environmental conditions outside their current realized niche.
• Epiphytic cacti showed the greatest exposure to novel climates, and current richness hotspots are particularly vulnerable.

Conclusions:

• Climate change is projected to become a primary driver of cactus extinction risk.
• 60-90% of assessed cactus species may be negatively impacted by climate change and/or other anthropogenic processes.
• The number of cactus species at risk is expected to increase sharply, necessitating urgent conservation strategies.