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Study in Nature warns of a decline of up to 30% in cactus species richness due to severe droughts
A study published in Nature highlights the vulnerability of cacti to climate change, warning that severe droughts could significantly reduce suitable habitats and increase extinction risks by the end of the century.
The article highlights the vulnerability of cacti to climate change and foresees scenarios involving significant losses of areas suitable for their survival, with high risks of extinction.
Chile is among five bioregions that could experience significant losses of cactus species by the end of the century, due to habitat changes associated with the occurrence of extreme climatic events, according to an international study published in the renowned scientific journal Nature.
Cacti—a family of plants comprising more than 1,900 species, most of them endemic to the Americas—are considered a symbol of resilience to extreme environmental conditions, but have proven to be highly sensitive to climate change.
The article—in which the University of Concepción participated—presents concerning data on the loss of areas with climates suitable for cacti, with an increased risk of extinction for up to 30% of species due to global warming and severe droughts.
“Because these plants are adapted to arid conditions, they were thought to be invulnerable to climate change. However, there is growing evidence showing that they are being severely affected,” commented University of Concepción researcher Pablo Guerrero Martin.
Extreme heat events could be an essential component of these impacts, stated the researcher, who is also a member of the Institute of Ecology and Biodiversity and the BASE Institute, and has extensive experience in studies on extinction risks, evolution, and the poaching of cacti.
The academic from the Faculty of Natural and Oceanographic Sciences is part of the team of authors of the study led by Michiel Pilliet, from the University of Arizona, which also includes Beatriz Mariño, a doctoral student in Systematics and Biodiversity.
Beyond the averages
The research highlights the vulnerability of this plant family to climate change, which is often underestimated by conventional species distribution models (SDMs), a tool used to assess or predict the status, distribution, or conservation problems of biological organisms.
Most of these models are based on climatic averages—temperature and precipitation—which leave out the impacts of extreme events, increasingly frequent and intense in the context of global warming.
Thus, the objective of the international study was to determine whether the explicit inclusion of severe climatic events in SDMs substantially changes predictions regarding cactus extinction risks under climate change.
The researchers used new spatial data on severe droughts—including the combined effects of higher temperatures—drawn from a database of cactus records comprising more than 688,000 observations.
Using these data, scenarios were modeled for 993 species through the end of the century, yielding more drastic projections than those provided by conventional models.
“Projections for the future of climatically suitable areas for cacti, that is, areas ideal for their growth, reproduction, and survival, change considerably when the models incorporate severe droughts,” explained Dr. Guerrero.
This suggests that, when defining the climatic conditions in which cacti can live, the intensity and duration of extreme episodes may be more relevant than average rainfall, added Beatriz Mariño.
The study projected that 66% of the 993 species modeled using severe drought variables would experience a reduction in areas suitable for their survival, compared with 55% in models that did not include these variables.
The magnitude of these reductions would also depend on the dispersal capacity of the species—that is, their ability to migrate to more favorable locations—in combination with climate change scenarios.
Projections indicate that when dispersal is not possible, between 84% and 85% of species would lose areas with suitable climates, compared with the 69–72% predicted by conventional models.
With a dispersal capacity of 100 kilometers, models incorporating severe drought data increased the proportion of affected species from 58–61% to 69–72%.
Likewise, the observations indicate that between 55% and 58% of cacti could lose at least one-quarter of the areas optimal for their survival, while between 25% and 35% would lose 80%.
A discouraging future
In the assessment of species richness, projections showed significant declines in several areas of high species concentration, highlighting five bioregions: Chile and the border area with Argentina, with 29%; Central America, with 32%; and Peru, Ecuador, and part of central Colombia, with 34%.
In some areas of Central America, the Venezuelan coast, and northwestern Brazil, the reduction in species would exceed 50%.
“Although these projections refer to the end of the century, it is important to note that we are already observing impacts that are currently limiting plant distribution,” stated the article’s lead author, Michiel Pilliet.
Pilliet indicated that this work will help update the conservation assessments of the International Union for Conservation of Nature (IUCN) Red List, which currently classifies 31% of cactus species as threatened.
The researcher foresees a discouraging future for these plants if the persistent threats of habitat destruction and illegal collection are added to these projections.
“In Chile, this concern also has a present-day counterpart. The article shows specimens of Copiapoa solaris affected by drought in Antofagasta. Their ability to store water does not make them immune to prolonged droughts intensified by warming,” said Pablo Guerrero.
In the academic's view, these results reinforce the urgency of protecting their populations and strengthening the monitoring of their survival and regeneration.
This work represents a contribution toward advancing understanding in an area of climate change that remains poorly understood: its effects on species distribution and extinction risks.
And although the study focuses on cacti, its authors believe the results could be relevant to the assessment of other plant families.
Specimens of Copiapoa dealbata growing in their natural habitat in the arid landscapes of northern Chile.
A flowering specimen of Copiapoa esmeraldana in its natural habitat in Pan de Azúcar National Park, northern Chile.
Two flowering specimens of Eriosyce krausii, displaying bright yellow flowers in the arid environment of northern Chile.
Findings from a study spanning the Americas show that climate-change forecasts are underestimating threats to biodiversity – even to exceptionally resilient species – by not factoring in extreme weather events that become more likely in a warmer world.
New research published in Nature revealed a dramatic decline in suitable habitat for the majority of nearly 1,000 cactus species studied when incorporating severe drought data into existing climate distribution models.
An international team led by researchers at the University of Arizona and the University of South Florida found that more than a quarter of cactus species analyzed could lose at least 80% of their suitable habitat by the end of the century. Projected diversity declines could be especially severe in important cactus diversity hotspots like Chile, Peru and northeastern Brazil. This level of loss could qualify these cactus species as Critically Endangered, according to criteria established by the International Union for Conservation of Nature, which would more than double the number of species currently in this category.
One of the great challenges in biodiversity science is predicting how life on Earth will respond to a changing climate, according to Brian Enquist, a plant ecology professor at the U of A and senior author on the study.
"For decades, we have relied on average temperature and precipitation to understand how species will be impacted by changing climate and who will likely persist," he said. "But organisms do not experience averages alone. They must also survive the extremes. Our study shows that accounting for these extremes can fundamentally change how we assess the future of biodiversity."
The authors suggest similar impacts will be seen in many other plant groups when accounting for extreme weather events with future climate scenarios.
"Climate change makes extreme events more frequent, but such events are typically excluded from large-scale forecasts," said the study's lead author, Michiel Pillet, who did the work as part of his dissertation at the U of A and is now a post-doctoral researcher at USF. "For this study, we integrated severe drought projections into models, which is quite novel, and extrapolated that at large scales with a plant family that is adapted to drought conditions. Our findings indicate that these adaptations may not be sufficient in a future with longer and more intense droughts."
Conventional distribution models typically rely on long-term temperature and rainfall averages but fail to capture the damaging effects of extreme events such as droughts, hurricanes and cold snaps on biodiversity. By incorporating newly available global data on future droughts with records from biodiversity databases, field observations and the community science network iNaturalist, researchers were able to improve predictions of future impacts.
While cacti are icons of desert environments, they inhabit nearly all types of ecosystems across the Americas, from California to Florida, and from Canada to the southern stretches of South America. More than 30% of cactus species are already threatened with extinction, particularly from habitat destruction and poaching.
Research published in 2022 by Pillet and Enquist already showed that climate change will elevate this number, but the addition of severe drought vastly increases how much suitable area species stand to lose.
"Cacti have evolved an astonishing range of forms and strategies that allow them to persist in some of the driest environments on the planet," Enquist said, explaining that impacts of severe drought are already visible in the Southwest, including Arizona, "with large-scale mortality of chollas, prickly pears, and even the mighty saguaro."
"Droughts in the last few years have contributed to stunted saguaro growth and reproduction, and killed many plants in some areas," Pillet added. "These effects also impact the many animal species that rely on these cacti for habitat and food."
The research was informed by a cadre of scientists across the Americas, including in Chile, Peru, Mexico and Cuba, and from institutions including the Desert Botanical Garden, Conservation International and the IUCN Cactus and Succulent Plants Specialist Group. The study was aided by additional data from iNaturalist.
"What we are seeing on the ground are some cacti populations that are already experiencing reductions in habitat and nearing extinction risks due to this combination of climate and extreme events," said Pablo Guerrero, a professor of botany at the Universidad de Concepción in Chile and co-author of the study. "The data and modeling allow us to reveal the extent of this surprising development across geographic scale and hopefully inform how we proceed in conserving and protecting what we can."
"Though these forecasts are for the end of the century, it is important to note we are already seeing impacts that are limiting plant ranges today," Pillet said. "Our results will inform updated IUCN Red List conservation assessments, and we expect the outlook for cacti will be grim, especially when our projections are combined with ongoing threats of habitat destruction and illegal collection."
Severe drought and warming increase the extinction risk of cacti
Article Publication Date
11-Nov-2026
During late spring and early summer, prickly pear flowers dapple the landscape with color in the Sonoran Desert near Tucson, Arizona, USA.
Credit
Daniel Stolte
Saguaro cacti in the Sonoran Desert are experiencing reproductive failures and mortality due to severe drought. The effects are made worse by invasive grasses, which outcompete small plants and increase the frequency of fires.
Credit
Ronald Souder
New USF-led research shows that even cacti are severely threatened in a warmer, drier world
Nature study finds climate change could put hundreds of species at risk of extinction
Drone footage of a densely populated cactus landscape in Oaxaca, Mexico. Cliffs are often cooler than the surrounding landscape, providing refuge for plants and animals.
TAMPA, Fla. (Nov. 11, 2026) – Findings from a study spanning the Americas show that climate-change forecasts are underestimating threats to biodiversity – even to exceptionally resilient species – by not factoring in extreme weather events that become more likely in a warmer world.
New research published in Nature, “Severe drought and warming increase the extinction risk of cacti,” revealed a dramatic decline in suitable habitat for the majority of nearly 1,000 cactus species studied when incorporating severe drought data into existing climate distribution models. The findings are embargoed until Wednesday, Nov. 11, 2026, at 11 a.m. ET and may not be shared until that time.
An international team led by the University of South Florida and University of Arizona found that more than a quarter of cactus species analyzed could lose at least 80% of their suitable habitat by the end of the century. Projected diversity declines could be especially severe in important cactus diversity hotspots like Chile, Peru and northeastern Brazil.
This level of loss could qualify these cactus species as Critically Endangered, according to criteria established by the International Union for Conservation of Nature (IUCN), which would more than double the number of species currently in this category.
Authors of the study suggest similar impacts will be seen in many other plant groups when accounting for extreme weather events with future climate scenarios.
“Climate change makes extreme events more frequent, but such events are typically excluded from large-scale forecasts,” said Michiel Pillet, lead author of the study and a post-doctoral researcher at USF. “For this study, we were able to integrate severe drought projections into models, which is quite novel, and extrapolated that at large scales with a plant family that is adapted to drought conditions. Our findings indicate that these adaptations may not be sufficient in a future with longer and more intense droughts.”
Conventional distribution models typically rely on long-term temperature and rainfall averages but fail to capture the damaging effects of extreme events such as droughts, hurricanes and cold snaps on biodiversity. By incorporating newly available global data on future droughts with records from biodiversity databases, field observations and the community science network iNaturalist, researchers were able to improve predictions of future impacts.
“When we started modeling and crunching the data, we were really skeptical of the initial findings,” said Brian Maitner, an assistant professor of integrative biology at USF and co-author of the study. “Then we consulted with cactus experts across North and South America and they confirmed that what we were modeling, they were already seeing in the field.”
While cacti are icons of desert environments, they inhabit nearly all types of ecosystems across the Americas, from California to Florida, and from Canada to the southern stretches of South America. More than 30% of cactus species are already threatened with extinction, including most species in Florida, particularly from habitat destruction and poaching.
Research published in 2022 by Pillet and Maitner already showed that climate change will elevate this number, but the addition of severe drought vastly increases how much suitable area species stand to lose.
“Cacti have evolved an astonishing range of forms and strategies that allow them to persist in some of the driest environments on the planet,” said Brian Enquist, a plant ecology professor at the University of Arizona and senior author of the study. “But there is something deeply concerning about discovering that even these plants may face substantial losses of suitable climatic habitat due to extreme events.”
The research was informed by scientists across the Americas, including in Chile, Peru, Mexico and Cuba, and from institutions including the Desert Botanical Garden, Conservation International and the IUCN Cactus and Succulent Plants Specialist Group. The study was aided by additional data from iNaturalist.
“What we are seeing on the ground are some cacti populations are already experiencing reductions in habitat, that are nearing extinction risks due to this combination of climate and extreme events,” said Pablo Guerrero, a co-author of the study and professor of botany at the Universidad de Concepción in Chile. “The data and modeling allows us to reveal the extent of this surprising development across geographic scale, and hopefully inform how we proceed in conserving and protecting what we can.”
Researchers emphasize that further work is needed to understand how drought affects different life stages, in what ways species may respond to changing conditions and which other plant (or non-plant) groups may be similarly impacted. Nevertheless, the study demonstrates that accounting for severe drought can substantially change forecasts of biodiversity loss — and indicates a growing challenge to identify which species face the greatest risks of extinction when extreme weather events are considered alongside long-term climate trends.
“Though these forecasts are for the end of the century, it is important to note we are already seeing impacts that are limiting plant ranges today,” Pillet said. “Our results will inform updated IUCN Red List conservation assessments, and we expect the outlook for cacti will be grim, especially when our projections are combined with ongoing threats of habitat destruction and illegal collection.”
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