By Michelle Kostuk
The water flooded my hiking boots and soaked my socks. I continued to trudge through the stream, enjoying the coolness. My three colleagues decided to rough it through the dense foliage on the banks of the Cienega Creek in Arizona. This was one of our monthly wildlife camera checks we conducted as citizen scientists for Arizona’s Pima County’s wildlife corridor monitoring project. Since we had been monitoring this site regularly starting in March 2019, we’d not only noticed trends in the animal populations using this stretch of land, but also noticed the spring’s water body depletion.
There were thick patches of bright-green algae suspended in the water. I took a deep breath and the scent, reminiscent of seaweed, filled my lungs. Tiny minnows darted underfoot and took cover in the thick algal masses. I sidestepped into clear water, where I could see the pebbles underneath.
The stream curved and opened into a larger perennial pool, which persists through the hot Arizona summers. I darted around the shallow edges of the spring and went up the bank to the tree where we had stationed our wildlife camera. The camera was encased in a camouflage-covered metal cage secured by a lock and a metal chain. I unlocked the apparatus and lifted the front of the metal cage off the camera and quickly scanned for spider webs. Handing the camera to my fellow volunteer, she put the SIM card into her computer. I pulled out some jerky and water from my day pack and then sat behind the computer with everyone. The screen flickered on as a minnow breached the surface of the pool located beyond the screen, cascading ripples to the edges of the bank.
A shock of green in the desert, Cienega Creek is one of Arizona’s most important water habitats, yet its permanence is increasingly threatened by climate change. As temperatures rise, the area is becoming more arid, diminishing the connectivity between the pools and streams, such as those I frequented in 2019 as part of the citizen scientist project for Arizona Pima County’s wildlife camera corridor project. This is not the only issue facing Arizona streams, water, and land. Forests are growing thick because of management choices and now burn hot when there is a fire. The rain and snowmelt runoff after a devastating fire, which has altered the landscape, is choked with debris. This debris-laden water is the source of recharge for the Colorado River Basin, the source of water for many southwestern states.
The Gila Topminnow (Poeciliopsis occidentalis) and Gila Chub (Gila intermedia) are two of the federally endangered species that are at risk as Arizona’s intermittent streams start to further separate and have a harder time connecting in the wet seasons. “Let’s say something bad happens and a population gets wiped out in one place. If these habitats are connected, then these fish can recolonize,” Daniel Allen, Assistant Professor of Biology at the University of Oklahoma, said in a phone interview.
Allen analyzed ten years, (2006-2016), of citizen scientist collected data from Cienega Creek performed by trained volunteers from The Nature Conservancy and the US Bureau of Land Management. The citizen scientists conducted yearly long-term wet/dry mapping surveys.
Allen created simulations and models to compare stream drying patterns with temperature, precipitation, streamflow, and drought conditions. In the areas that he studied in Cienega Creek; perennial water decreased by 14 %. As temperatures rise due to climate change, the habitat connection that local fish species need to survive could diminish, explained Allen. This threat to the habitat could push some species, such as the Gila Topminnow and Gila Chub, toward extinction.
Franklin Lane is a Citizen Scientist Team Leader for the Sky Island Alliance Spring Assessment Project. Despite this project not being affiliated with Allen’s research, Lane’s citizen scientist spring data collection methods are like those used in Allen’s research.
Lane and his wife go to their designated Arizona spring five times a year. They wake up at 5:30 in the morning to ensure they have enough time to hike to their location. Once there, Lane ties a measuring tape to a tree and then wades into the stream that is roughly sixty meters long. Every meter he takes a depth measurement. “I’ve done this by myself and that takes almost an hour and a half. My wife and I can do it in just under an hour. It really helps to have someone recording the data as you’re shouting it out,” Lane said. Lane does not analyze his own data, but Marco Robles, a Conservation Scientist with the Arizona Chapter of the Nature Conservancy, also uses similar citizen scientist data for his work.
While the southwest might be getting warmer, the full picture is more nuanced than the area simply getting drier. The Colorado River Basin supplies water to parts of California, Colorado, Nevada, New Mexico, Utah, and Wyoming, and all of Arizona. Robles commented that drier temperatures due to climate change are diminishing this reserve. “All the states had to recently renegotiate their treaty because of drought and water supply. The states are prioritized in terms of who gets what amount of water and Arizona is low on the list. This is not going to just impact the cities, but also agricultural use,” Robles said.
Another source of water in the Colorado River Basin is runoff from snow-melt, but rising temperatures and forest fire risk could threaten the efficacy of this water supply. “When we’re talking about the snow-pack, the data is really clear that warming is going to impact the water flow and the amount of water in the upper Colorado River Basin,” Robles said.
Arizona is drying and its water supply is diminishing. Yet another threat is the increase in forest fires, which threatens both water supply and quality. Fire management is playing a large role in these trends.
Over the last 100 years in Arizona, fire management has concentrated on prevention. While this has helped save buildings and property in the short term, this strategy has thickened forests with dense layers of underbrush. When fires burn, this clears out the forests and runoff is filled with debris that clogs water systems.
Trees take a long time to grow and open spaces are prone to a runoff in rain events. When it rains after a forest fire, local waterways become filled with debris. “Healthy forests are really good for the water supply from a water quality and water quantity standpoint. That is one of the risks of having unhealthy forests that are really dense,” Robles said. Now, the fires that rage in these forests burn hot and decimate the local forest communities.
There are many factors that play a role in how Arizona’s streams and basins are recharged and maintained. Climate change is making intermittent streams and the animals that depend on those water sources scarcer. Fire is transforming the way runoff water is collected in the Colorado River Basin. Many of the long-term data sets researcher depend upon are observed and documented by citizen scientists.
After previewing the charismatic mammals that paraded in front of our camera, we packed up and re-secured the camera so we could collect our data bounty for next month. As we walked back, I noticed the water-smoothed rocks shining brightly. During previous trips, those rocks had been submerged under the water. The signs of fire and climate change are not always apparent, but an apt observer can notice the trends and hopefully fathom the implications of these changes.
Note: Franklin Lane and the author are both a part of the Sky Island Alliance and the Arizona Master Naturalist Association.
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