Blog post on the work web site about our research into how saguaro cactus are impacted by fire.2/18/2020
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First we talk (and eat pastries and drink coffee), then we dig!! This was actually an great learning site for people, there was 1) buffelgrass, 2) bristlegrass, 3) cottontop, and 4) tanglehead, almost all of the similar looking grasses!
I and others contributed to an interesting case study on buffelgrass in the greater Tucson area. Check out this link and see whats going on.
https://usbr.maps.arcgis.com/apps/MapSeries/index.html?appid=3627aad031d44e33acda00a46e882147 Click the button below for a recent article by Laura Stack about our work in Pima Canyon and elsewhere. Pima Canyon is a beautiful canyon in the Santa Catalina Mountains. The US Forest Service manages this wild area. It is home to desert big horn sheep (Ovis canadensis nelsoni), which is a subspecies of big horn sheep. An estimate from March 2017 by AZ Game and Fish puts the population size at 85 individuals. * For the past eight months a team of volunteers has been working to remove buffelgrass from Pima Canyon. People who live in the Catalina Foothills have watched the steady encroachment of buffelgrass across these slopes and through their neighborhoods. Last year we received a grant from the National Forest Foundation to reach out to the community about the dangers of buffelgrass, to start a volunteer buffelgrass control group, and to hire youth crews to come out after the rains to help us battle this invasive plant. It has been so rewarding to work with this community, helping folks understand the problem, showing them how to identify the plant, and teaching them what they can do to help. Even more satisfying (because it was outside and with a great group of people) was helping to organize a volunteer manual control buffelgrass crew. From October 2017 through May 2018 we met in Pima Canyon twice a month to dig out buffelgrass through the morning hours. The terrain was rocky, sometimes steep and rife with saguaro, cholla, and other pokey plants. To dig out buffelgrass we paired up into groups of two and one person would hike out with a 20 lb. digging bar while the other carried a rock hammer. The buffelgrass was quite dense in most areas that we worked and the digging bar was the tool of choice. It is important to get this bunchgrass out by the roots so one person would hold the grass by the top, pulling it out of the way while the other person would use the bar to pry out the grass. We would shake the remaining soil out of the roots and then stack the grass in a lattice formation to limit the spread of the seeds and subsequent sprouting. The best apart of this endeavor was the enthusiasm and dedication of the volunteers. The people that have chosen to give their time in this way come from many different backgrounds. Some have just moved here and want to learn, others have lived here for decades and already know what a menace buffelgrass is. When you go out and spend a few hours on the hillside with a digging bar and rock hammer, you can see the difference that it makes to at least that small spot. We all loved uncovering and “freeing” young saguaros from the stranglehold of buffelgrass. We had the opportunity to see interesting plants and animals while we are out there. One volunteer often brought binoculars and we would take breaks and look at big horn sheep on the rocks. We saw numerous snakeskins, coyote and deer scat, a murder of crows, many different birds’ nests, and packrat middens stuffed full of cholla segments. One old saguaro skeleton had a perfectly preserved boot (the hard shell that the saguaro builds when it is damaged by birds making nests in the cactus) and we awed over the many generations of birds that must have been raised in it. When we began this endeavor in October, we would wear extra layers in the morning until we warmed up with the work and the day, but by the time we stopped going out in May we were starting at 6:30 and making sure to bring a lot of water! Whenever I describe pulling buffelgrass it always sounds hard and arduous, but I don’t think that I am alone in saying that it is actually a lot of fun. Working outside in this place of immense beauty, with other people that care, what could be better? We have not cleared all of the buffelgrass out of Pima Canyon, but we have saved hundreds of saguaros and many, many other plants, and in the process we learned a lot about our desert backyard, about ourselves, and about each other. * https://tucson.com/news/local/bighorn-sheep-surviving-possibly-thriving-in-tucson-s-catalina-mountains/article_3123e685-d61e-5a52-857e-20513dfbafb2.html This year, like many years, the City of Tucson put on a 4th of July fireworks display overtop of A Mountain for all to enjoy. This would not be a problem for a typical Sonoran Desert landscape that has natural open space among its scattered trees, shrubs, and cacti and thus a very low potential to burn. However, this hill that lies nestled in the heart of the city is largely covered with the invasive grass — buffelgrass. Buffelgrass is an excellent fuel, capable of producing hotter fires that move faster and further than our native vegetation could possibly produce. On this 4th of July, I had just flown in from a family member’s wedding. Driving home from the airport we noticed that the hillside was on fire. One (or more) of the fireworks had set fire to some of the bone-dry grass, and the fire was rapidly spreading across the hill. We could see saguaros engulfed in flames. As part of my work with the University of Arizona and the Arizona-Sonora Desert Museum, I went out over the subsequent weeks to map the area of the fire and to study the mortality of the saguaros and other perennial plants on the hillside. The following is a photo essay to illustrate the problem of buffelgrass. We will not know the exact number of saguaros lost for some time, but over 200 were burned in the fire. The pictures above show what the area looked like directly after the fire. Picture 1 shows burnt baren ground immediately after the fire. Picture 2 shows the buffelgrass sprouting days after the fire out of the burnt buffelgrass. Picture 3 shows the buffelgrass sprouting across the hillside. These pictures are from a few weeks after the fire. Buffelgrass is already up to my thighs in some places. Picture one shows green healthy buffelgrass growing up around a burnt saguaro. Picture 2 shows the hillside covered in lush green buffelgrass. Picture 3 shows another view of a burnt saguaro with fresh buffelgrass.
This blog is going to be brief as I am pretty busy right now. I have recently started working with the Arizona-Sonora Desert Museum on all things buffelgrass.
What is buffelgrass and how does this relate to seabirds? Well buffelgrass is an invasive grass that causes massive problems for the Sonoran Desert where I currently find myself. It doesnt have anything to do with seabirds, but it has everything to to with ecology and conservation, which is what I have really been working on all along. Why is buffelgrass so bad? Because it moves in to a low fire ecosystem, crowds out native plants and spreads fires further and hotter than the native vegetation is adapted to. Being a grass it also spreads really easily and does fine on low water and hot summer temperatures. I am humbled and inspired in this new position to do what I can to facilitate more effective work on controlling this scurge. Here I have also linked a blog post that my supervisor wrote about buffelgrass. I will be posting more on this in the future I am sure. September, 2016 In late August, the kids, the dog and I were lucky enough to accompany Sky Island Alliance to Aravaipa Canyon Wilderness to assist The Nature Conservancy in some restoration work. This was a great opportunity to learn about native grasses, history of cattle grazing, and about the Sonoran Desert/ Apache Highlands ecotone. It was also beautiful. Aravaipa Canyon is an isolated canyon with a perennial stream, high cliffs, and supposedly bog-horned sheep (though we did not see any). This is an 11-mile canyon in the Northern Galieros Mountains.We did see black-tailed rattlesnakes, a tarantula, a wind scorpion, a pocket mouse, and so much more! Hundreds of little plugs of alkaline sacaton, Sporobolus airoides, and giant sacaton, Sporobolus wrightii got planted. We planted in a long plot that TNC had seeded in hay seed to produce a mixture of native and non-native grasses to produce hay. Mark Haberstich of TNC has worked towards using native grasses to feed cattle, and the cows seem to like it. We also planted the two spp. of sacaton in a wash further north where they are attempting to slow down and widen the water flow to allow for more water to stay in the ecosystem. The river experienced decades of overgrazing and driving right in the river. This helped to channelized the flow. When TNC acquired Cobra ranch in 2007 they were able to reduce the number of cattle on the land and begin to rehabilitate the river. They installed juniper posts back in 2012 in strategic places to slow down water and trap debris and sediment. The sacaton is hardy and can withstand flood conditions in the stream bed as well as desert conditions once it is established. Last week I was fortunate to go out with Dr. Aaron Flesch and his Irish assistant Vincent. We headed out to Cienega Creek Preserve around 3 PM. Our first task was to hike out to saguaro cactus that had been identified in previous nights as potential elf owl homes. We searched the xeric riparian habitat for traces of owl poop. Elf owls, being one of the smallest owls also have very small poop. Being accustomed to looking at seabird poop, looking for tiny smears of elf owl poop took some adjustment (see picture). When we found sign we looked in nearby saguaros for cavities, preferably with a little bulge below the opening. A long telescoping pole was then used to carry a camera up the saguaro and into the hole to see who, if anyone was inside. We were fortunate with three positive elf owl IDs in the course of the afternoon and one Gila woodpecker family. The surprising thing to me about seeing these owls was the fact that they were stacked up inside the cactus. I had imagined that they would sit side by side, but nope, they are stacked right up. In the picture here you can see the corner of one of their eggs and on top of the eggs are two birds. The top bird is clear, but if you look, you can see that there is another bird underneath. The cactus apparently has such a high water content that it acts as insulation buffering the owls from the intense heat that we are experiencing right now. The other interesting fact was that all of the elf owl burrows were oriented in a generally west/ southwesterly direction, probably for temperature control. Other birds seen while we were hiking around:
Coopers Hawk (and its nest) Gila woodpecker (in cavity) Grey Hawk Curve-billed thrasher Red-tailed hawk (pair and their nest) Lesser goldfinch Black-throated sparrow Blue grosbeak Ladder-backed woodpecker Lesser nighthawk White-winged dove Yellow-breasted chat (heard only) Great horned owl Western screech owl (heard only) After the sun went down we were trying to locate other possible nests, usually in areas where they had been heard before, we attempted to better pinpoint where the birds were nesting. This involved splitting up, playing elf owl calls and trying to determine where they were coming from. There were other variations of this at different sites that we hiked to in the preserve. This being Arizona in June, the sky was clear and the stars were bright. Mars and Jupiter were out early and very bright, Leo and others soon followed. I could hear other little animals scurrying around after dark, but except for one pocket mouse, never got to see what they were. Pictured below are elf owl poop, saguaro cactus and an assortment of desert plants |
Julia A. RoweI am an ecologist interested in an interdisciplinary approach to conservation and natural resource problem solving. Archives
February 2020
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