A photo essay
Molly Taft - Monday
Molly Taft - Monday
An Iconic Species
“For me, what’s so wonderful about saguaros is really kind of the way that they move people,” Swann told PBS. “And a lot of people who live here will tell you that one of the reasons they live here is because of this plant.”
A saguaro in the Sonoran desert near Apache Junction, AZ.
One of the Southwest’s most familiar plants may be in deep trouble. The towering, multi-armed saguaro cactus, which is found only in the Sonoran Desert in Arizona, California, and parts of Mexico, has faced increasing instability as climate change alters its natural habitat through droughts and wildfires. The cacti can live well over a century and are culturally important to the tribal nations native to the Sonoran, as well as crucial to the larger ecosystem of the desert.
“We’re trying to understand how changes in temperature and precipitation in the future might affect the reproductive potential of saguaros, everything from how old they are when they start reproducing to how many flowers do they produce,” Don Swann, a biologist at Saguaro National Park, told PBS.
Long-Lived Giants
Saguaro in the desert.
Saguaros stick around for a while: They can live on average between 150 and 175 years and generally don’t reach maturity until 35 to 65 years old. This longevity helps the cacti survive the extremes of their natural habitat, as the cactus’s resilience to drought increases as they grow. Older cacti are able to store large amounts of water and withstand unusually dry seasons. Smaller cacti, meanwhile, generally rely on the moisture in the ground to survive and may not last through a season where the soil is dried out. Younger cacti generally need several seasons of favorable growing conditions with plentiful rains to develop to maturity.
Fewer Younger Cacti
A fallen saguaro rots
Experts say that there have been fewer and fewer younger cacti around as climate change has intensified drought conditions. A 2018 survey conducted by the National Park Service in Saguaro National Park found that, of 10,000 cacti surveyed, just 70 were under 15 years old.
“Although the population of saguaros in Saguaro NP is quite healthy, establishment of young saguaros has nearly ceased since the early 1990s in nearly all habitats,” the report concluded.
Younger Cacti Are Less Resilient
A flowering saguaro cactus.© Photo: Hal Beral / VWPics (AP)
“The older they are, the more resilient they become to deeper and deeper droughts, right?” Swann told PBS. “So they’re very resilient when they’re 60 years old, but they’re not very resilient when they’re 5 years old.”
Invasive Plants Also a Problem
A forest of saguaro cacti among other plants.
“For me, what’s so wonderful about saguaros is really kind of the way that they move people,” Swann told PBS. “And a lot of people who live here will tell you that one of the reasons they live here is because of this plant.”
A saguaro in the Sonoran desert near Apache Junction, AZ.
One of the Southwest’s most familiar plants may be in deep trouble. The towering, multi-armed saguaro cactus, which is found only in the Sonoran Desert in Arizona, California, and parts of Mexico, has faced increasing instability as climate change alters its natural habitat through droughts and wildfires. The cacti can live well over a century and are culturally important to the tribal nations native to the Sonoran, as well as crucial to the larger ecosystem of the desert.
“We’re trying to understand how changes in temperature and precipitation in the future might affect the reproductive potential of saguaros, everything from how old they are when they start reproducing to how many flowers do they produce,” Don Swann, a biologist at Saguaro National Park, told PBS.
Long-Lived Giants
Saguaro in the desert.
Saguaros stick around for a while: They can live on average between 150 and 175 years and generally don’t reach maturity until 35 to 65 years old. This longevity helps the cacti survive the extremes of their natural habitat, as the cactus’s resilience to drought increases as they grow. Older cacti are able to store large amounts of water and withstand unusually dry seasons. Smaller cacti, meanwhile, generally rely on the moisture in the ground to survive and may not last through a season where the soil is dried out. Younger cacti generally need several seasons of favorable growing conditions with plentiful rains to develop to maturity.
Fewer Younger Cacti
A fallen saguaro rots
Experts say that there have been fewer and fewer younger cacti around as climate change has intensified drought conditions. A 2018 survey conducted by the National Park Service in Saguaro National Park found that, of 10,000 cacti surveyed, just 70 were under 15 years old.
“Although the population of saguaros in Saguaro NP is quite healthy, establishment of young saguaros has nearly ceased since the early 1990s in nearly all habitats,” the report concluded.
Younger Cacti Are Less Resilient
A flowering saguaro cactus.© Photo: Hal Beral / VWPics (AP)
“The older they are, the more resilient they become to deeper and deeper droughts, right?” Swann told PBS. “So they’re very resilient when they’re 60 years old, but they’re not very resilient when they’re 5 years old.”
Invasive Plants Also a Problem
A forest of saguaro cacti among other plants.
© Photo: Jon G. Fuller / VWPics via AP Images (AP)
It’s not just high temperatures that are threatening the cacti. Invasive plant species like buffelgrass have been increasingly showing up in the saguaro’s habitat over the past 20 years. This grass can provide fodder for the wildfires that sweep through the desert.
Saguaro at Danger From Wildfire
Saguaro cacti at sunrise.© Photo: Charlie Riedel (AP)
Saguaros are not adapted to withstand wildfire, and these blazes have been devastating to the cacti. The Bighorn Fire, which was sparked by lightning and burned nearly 120,000 acres between June and July 2020, killed an estimated 2,000 cacti.
Non-Native Grasses Fuel Fires
The Carefree Complex Fire, which burned through the Sonoran
It’s not just high temperatures that are threatening the cacti. Invasive plant species like buffelgrass have been increasingly showing up in the saguaro’s habitat over the past 20 years. This grass can provide fodder for the wildfires that sweep through the desert.
Saguaro at Danger From Wildfire
Saguaro cacti at sunrise.© Photo: Charlie Riedel (AP)
Saguaros are not adapted to withstand wildfire, and these blazes have been devastating to the cacti. The Bighorn Fire, which was sparked by lightning and burned nearly 120,000 acres between June and July 2020, killed an estimated 2,000 cacti.
Non-Native Grasses Fuel Fires
The Carefree Complex Fire, which burned through the Sonoran
in 2005, rolls toward a stand of saguaro cacti.
© Photo: Jeff Topping (Getty Images)
“We have this increase of non-native grasses, the grassification of the Western United States and in many of the deserts,” Ben Wilder, a desert ecologist, told PBS. “And that drives a fire regime and introduces a fire regime to the desert that’s pretty novel.”
Cacti Don’t Have Time
A close-up of a saguaro’s spines.© Photo: Jon G. Fuller / VWPics (AP)
The 2018 NPS survey also found that younger saguaros had been spotted growing recently in rocky areas, which could suggest they’re leaching moisture from water caught in the rock cracks. But the long growth period of the cactus means that the rapid climate changes we’re seeing in the West may not give the plants enough time to adapt to the new conditions.
An Iconic Species
Saguaro framed against oncoming monsoon clouds.
“We have this increase of non-native grasses, the grassification of the Western United States and in many of the deserts,” Ben Wilder, a desert ecologist, told PBS. “And that drives a fire regime and introduces a fire regime to the desert that’s pretty novel.”
Cacti Don’t Have Time
A close-up of a saguaro’s spines.© Photo: Jon G. Fuller / VWPics (AP)
The 2018 NPS survey also found that younger saguaros had been spotted growing recently in rocky areas, which could suggest they’re leaching moisture from water caught in the rock cracks. But the long growth period of the cactus means that the rapid climate changes we’re seeing in the West may not give the plants enough time to adapt to the new conditions.
An Iconic Species
Saguaro framed against oncoming monsoon clouds.
Photo: Mario Tama (Getty Images) unless otherwise attributed
“For me, what’s so wonderful about saguaros is really kind of the way that they move people,” Swann told PBS. “And a lot of people who live here will tell you that one of the reasons they live here is because of this plant.”
“For me, what’s so wonderful about saguaros is really kind of the way that they move people,” Swann told PBS. “And a lot of people who live here will tell you that one of the reasons they live here is because of this plant.”
No comments:
Post a Comment