What Does Phoenix’s Record Dry Monsoon Mean for Local Plants?

Around 50% of the plant diversity in the Sonoran Desert comes via short-lived planet species—so when the rain doesn’t come, neither do those plants.

The Phoenix area faced an especially dry monsoon this summer, getting only 0.15 inches of rain at a time when the Valley usually receives a much-needed smattering of rainfall.

To make matters worse, it was a summer of not only extreme dryness, but extreme heat, too. The National Weather Service recorded a 31-day streak of high temperatures at or above 110 degrees Fahrenheit.

RELATED: Phoenix Has Driest Monsoon Season Since Weather Service Began Record-Keeping in 1895

A dry monsoon season—which typically runs from June through September—doesn’t just negate the relief Arizonans get from the overbearing heat, it also harms local plant life.

No Rain = Much Fewer Plants

Dr. Elizabeth Makings, instructor at Arizona State University and curator of its herbarium, said all plants are affected by a dry monsoon, but especially local herbs.

“[They’re] especially vulnerable in the short term since they don’t have extensive root systems to rely on in dryer times, and rely on wetter conditions to persist,” she said. “It’s really no different than your summer garden—if you don’t water those seeds or starts, they don’t germinate and survive.”

Makings said around 50% of the plant diversity in the Sonoran Desert comes via short-lived planet species. So when the rain doesn’t come, neither do those plants.

Those plants are at the bottom of the food chain, so when their growth is stunted, there are knock-on effects all the way up the food chain.

“Plants are the primary producers,” Making said. “Everything relies on them. There is no fauna without plants, so they are critical to every terrestrial ecosystem—from the microbes to the invertebrates to the vertebrates.”

Despite desert plants being built for periods of low moisture, even they have their limits. They are still plants, which means they still need water to survive.

“After a season of little rain, they seem to be able to bounce back, but consecutive seasons without adequate moisture is stressful for even the toughest plants,” Makings said. “I have sadly seen a lot of mortality in the desert lately. Couple climate change with increasing fires and you have a very troubling situation.”

“I think we really have to consider proper land management and conservation measures of our natural areas as a huge priority,” she added.

Part of a Larger Problem

Plants aren’t just failing to stay alive due to natural droughts, but also from human-caused climate change. Overgrazing from livestock, greenhouse gas emissions, and off-road vehicles are all things people do to harm local flora, Making said.

On the flip side, there are things people can do to protect their natural environment:

• Support conservation efforts of local land managers.
• Volunteer to do restoration work.
• Plant a pollinator garden.
• Make conservation a priority where they live.
• Get involved in land use decisions.

“Thoughtful decisions about how to manage our public lands should be prioritized in the face of the current climate crisis if we want to be able to enjoy these beautiful places. Not in some distant future, but today,” Making said.