Salt River Ecological Report
Ecological Report on Salt River (AZ) Wild Horse Herd & Associated Ecosystem
By Craig C. Downer, Wildlife Ecologist, President: Andean Tapir Fund, P.O. Box 456, Minden, NV 89423.
This area is a riverine habitat set within the great Sonoran Desert ecosystem, and it is crucial for maintaining the native plant and animal diversity of the region. Since water is the key limiting factor of desert life, the importance of a river to its adjacent life communities is a critical one. Ecologists and naturalists have recognized the Salt River for its great variety of birds, and the Audubon Society has been quite active in conservation projects, including the annual Christmas Bird Counts. Also fish are very diverse and abundant here. This ecosystem has many features of a marshland, which accounts for its high annual productivity in terms of biomass, in areas that are not overly polluted or otherwise degraded.
As a wildlife ecologist, my primary purpose for visiting the Salt River ecosystem was to observe its wild horse inhabitants and to assess their health and population as well as their impacts/contributions to the whole life community, including humans.
In general during my three days, I observed that each band usually maintained a space of at least a few hundred yards from other bands, except for rare times such as in the late afternoon when I did observe a few bands coming together. Each band usually kept moving so that no particular portion of the river habitat became over-browsed or grazed.
I soon began to notice how these wild river horses were eating the fresh water Eelgrass much of the time. This I consider a positive ecological contribution that prevents the clogging of the river, especially during periods when the Stewart Mountain Dam releases less water. I had been told by locals that there were times when very little water was released and the river slowed to a trickle. The river bank revealed high flows and even flood stages in the recent past, and the present flow was quite full. If the flow is often cut drastically, then many species would appear to have a tortured life history, past, present, and future.
During the late afternoon float, we observed large willow trees, some of which were being moderately browsed by the horses. “Continental species of conservation concern” observed here include the Abert’s Towhee and the Southwestern Willow Flycatcher (also endangered). Marsh Wrens, Great Blue Herons fishing in the shallows, and groups of Turkey Vultures circling high overhead, Snowy Egrets and Belted Kingfishers were also frequently observed. Large-mouth Bass propelled themselves bodily out of the water in the early evening, making loud thumps and splashing sounds that carried a long ways. Sunfish were also present. Around 100 or so recreationalists were also present, many in kayaks or boats of various sorts. Many were fishing. There were many pink or reddish clusters of small gelatinous eggs plastered on herbaceous stems at the edge of the river, which were probably those of a frog. I noticed several small Lowland Leopard Frogs, which the herons seemed to be hunting with their stabbing beaks along with fish. Nesting Bald Eagles were reported to me by locals as well as Joe Bobian. Several species of Dragon Flies were observed, including a large 3”-winged, orange one. Mosquitoes came out at sundown. Small biting Black Flies were also present. Sign of Muskrats were detected on the river banks. Beaver were also gnawing on some trees on the north bank and there was sign of a former beaver, submerged when the river was at a higher level.
The north side of the river had considerable cattle, and ca. 100 were observed during my three days on the river, compared with about a half as many wild horses, i.e. ca. 50. Many of the cattle were on the reservation and causing much habitat destruction. The south side of the river, however, did not display such habitat destruction except where people and their activities, including ORVs and garbage were negatively impacting. This indicated that the wild horses, present on both sides of the river, were not causing such destruction. It would be both dishonest and unfair to blame them for habitat destruction being caused by cattle or by people. For truly they are restorers and healers here.
I directly observed many positive contributions that these horses were making to the riparian ecosystem. A variety of seedlings sprouted from the horses’ droppings and included those of the thorny Acacia tree common here and whose leaves and twigs I observed the horses eating. Their pruning of this tree or eating of its seedlings maintains open areas and habitat diversity by preventing this tree’s overcrowding of the ecosystem.
Of all the species I observed the horses eating, the river or fresh water Eelgrass seemed to log the most time in the horses schedule. Perhaps this was because they had to work hard at pruning these tough leathery ribbons with their upper and lower incisors and at the same time tug them out of the water. Sometimes I observed them flinging this vegetation, perhaps to clean it of clinging mud particles. There were other types of river vegetation, one of which was Potamogeton, which was also eaten.
While investigating a sandy island, I observed a horse wallow area in the river-washed sand. There were also trails that wove from the rivers through the thickets and out into the upland Sonoran desert hills, with their colorful and statuesque cacti. Some tree trunks were used as rubbing posts, and some shady groves were occupied for shade and for concealment. Puma occur here, as well as coyotes and bobcats. Puma can take young horses or weakened, diseased or declining, older horses, especially in ambush. Shortly prior to my arrival, one unfortunate, dark-colored stallion had become entangled in barbed wire, which cut deep into the flesh above his hoof. Though we persistently searched for him during the three days in an effort to help him, he was no longer to be seen. It is possible that a puma had followed the bloody trail left by his wound, then overtook and killed him through strangulation, which would have been merciful in the end. Abandoned barbed wire fences are particularly a problem on the north side of the river where the cattle occur and should be removed here as well as on the south side of the river, where there are also many fences. These are real hazards for many animals, including both species of deer found here: the Mule Deer and the Whitetail Deer.
On a sandy island in the middle of the river, I gathered evidence that horse feces were clearly helping to build the soils by contributing to their humus component and by dispersing many intact seeds of a great variety of plant species, including the Acacia, along with some Mints, and members of the Sunflower Family, Asteraceae. I also observed many Squash seeds that had been deposited in tact in the horse feces. This ecological contribution by the horses is quite major and serves to increase the diversity of plant and animal species in many ways (See Downer, Ch. 2). I have done detailed studies of this sort and could so again given adequate support. From what I saw of the river and its riparian habitat, the wild horses are not over-populating, but are at a numerical level that is in balance with the other species and well spaced. Their removal or major reduction would have a dis-equilibrating effect upon the Salt River ecosystem.
Wild horses have been here for centuries, dating back to Spanish missionary times, three to four hundred years ago. They were also present during the passage of the 1971 Wild Free-Roaming Horses and Burros Act of 1971 (P.L. 92-195) and are legally entitled to protection within the Tonto National Forest. Please note that the U.S. Forest Service, under USDA, (along with the BLM, under USDI) is also charged with preserving, protecting, and managing the wild horses as “principal” resource recipients within their legal territories (USFS). (See section 2 c of this act, & Downer, pp. xi-xiii.)
Rather than removing or greatly reducing the modest population of wild horses here, Tonto National Forest officials should focus on clearing up all the garbage that has accumulated for many years in and around the Salt River, and prevent its further accumulation. Officials should also restrict recreational vehicles, such as ATV’s and motorcycles, as well as certain river craft, that are having damaging effects on the stream banks and other riparian areas, or upon the river itself.
The majority of the horses I viewed were in good shape with Heineke scores of between 4 & 5, with a few 3’s and a few 6’s. Present were a reasonable number of foals and yearlings. The latter were not at all excessive as would indicate a population boom. The wild horses were establishing a harmonious balance within the Salt River ecosystem and contributing positively to this.
An important aspect of a Salt River wild horse band’s year-round life is its occupation of the upland Sonoran desert habitat. The band trails I followed led into the surrounding upland ravines and mountains, some with spectacular red sandstone formations. This indicates that the wild horses are being true to their ancient, semi-nomadic nature. They are distributing their grazing and browsing pressure over very large areas involving hundreds of square miles, thus minimizing their impacts on any given part of their home range and allowing this to regenerate. Such a wholesome lifestyle, attuned to seasonal variation, stands in marked contrast to the domestic cattle I observed, either directly or indirectly, concentrating their grazing and browsing pressure along the northern side of the river, and trampling and over-consuming vegetation. This is causing increased erosion of soils as well as putrid, stagnant conditions along certain river plains where the excess urine and feces of cattle become a breeding ground for dangerous bacteria and disease-conveying mosquitoes, which brings me to my next topic.
Examining the water of Salt River, I realized it carried a high nutrient, including Nitrogen, load. Although it did not show signs of extreme eutrophication, if the volume of water released from the Stewart Mountain Dam to the east were to be decreased, such eutrophication could set in to the detriment especially of animal life. This would result in a harmful concentration of anaerobic bacteria and the depletion of oxygen from the water with attendant die-off of fish, amphibians, many invertebrates and dependent reptiles, birds, and mammals of a great variety. Also of concern is the introduction of pesticides, herbicides, chemical leaching from nearby mines, air pollution, sewage from homes and businesses, and the general littering of plastics, tin cans, picnic garbage, etc., from visitors. I could tell the situation was serious when I visited certain river edges with little current on the slow side of bends. These were becoming very eutrophied and had gobs of algae floating in them as well as masses of floating plastic refuse, some of which is ingested by animals or tangles them up and even strangles them. The wild horses’ daily visits to the river significantly aid in more thoroughly circulating its waters. Also, by wading or swimming through and eating the river vegetation and then moving inland to deposit their feces in drier uplands (which build their soils), the horses assist in preventing eutrophication and keep the ecosystem more open for deer and other animals to circulate. They aid in the aeration of the waters. The wild horses maintain and even enhance the ecological health of the river and its riparian habitat, as well as that of the adjacent Sonoran desert, with all its amazing variety of cacti, mesquite, succulents, herbs, grasses, forbs, bushes, and trees that have adapted to the hot and arid conditions here. Acting on the river bottoms, their hoof action serves to aerate stagnant areas and prevent toxic anaerobic conditions from developing. (See Downer, Chapter II.)
The life of the Salt River wild-horse-containing ecosystem begins to really stir during the crepuscular hours of late afternoon and early evening. At this time dramatic chases occurred between stallions competing for mares, and bass spectacularly leapt out of the river followed by the loud slapping of the river surface as they re-enter the water. I also heard the hoarse chorus of the gangly Great Blue Herons, the cheerful, cozy chatter of day-active songbirds seeking their protective roosts in bushes, and the energetic takeoff of ducks and geese, quail and doves, seeking their nocturnal abodes as well.
Finally I quote from the current November, 2012, issue of National Geographic Magazine in its “Next” section on “Horse Power”:
“Before Neolithic farmers began to till marshes in what is now Europe, grazers kept forests from creeping in, which allowed varied habitats for birds, insects, and plants to flourish. Today, conservationists are trying to revive that diversity. In many places that means cutting brush back with chain saws. But Koniks are cheaper and better at it. The horses are now at work in nearly a dozen countries – including some 20 sites in the U.K. alone.” (Williams.)
This tribute to the value of the horse in restoring and maintaining ecological diversity by preventing takeover of brush, etc., is directly applicable to the Salt River ecosystem. Salt River’s wild horses are positive assets. They should not be removed but rather allowed to fill their ancient niche within their ancestral lands in North America. They are post-gastric digesters who complement ruminant digesters, help build the soils, disperse intact seeds capable of germination for many valuable plant specis, prevent catastrophic wildfires, and maintain productive and bio-diverse riparian habitats, among other habitat types. We “two-leggeds” (old Indian term for humans) must learn to appreciate a wild-horse-containing ecosystem. It is a restored and enhanced one – and what’s more it is especially beautiful!
List of Species for Salt River riparian and aquatic and adjoining desert above Mesa AZ:
Some Wild Horse Observations and GPS (Geographical Positioning System) reading with corresponding observations of horses and other important items:
9/25/12: Band of 8 w/ 1 foal. Mid morning, upper river, eating.
9/26/12: 3 bands of wild horses seen, one w/ 4 wh’s, 1 w/ 8 wh’s (same as seen on 9/25), 1 w/ 3 wh’s. GPS: 33 d 32.720’ N; 111 d 40.264’W. 4,791’ elev. Time 12:32 pm. Horses feeding, grooming, bathing, splashing. Many small flies about, some large horse flies also. Horses swish tails, throw water, twitch skin to repel flies.
9/27/12: Same band of 6 observed in earlier days, observed followed. GPS: 10:32 AM. 33 d 32.366’N; 111 d 40.273’W. 1,327’ elev. On rocky island. Tiny white “ghost” lizard seen, ca. 3” long. Slender, rapidly ran to cover under tiny bush.
4:30 PM: Met Retired man fishing from small inflatable boat in river: Vaughn Dolle. He enjoys wild horses here and has observed them since 1967 (may substantiate the legal protection of Salt River herd under the Wild Free-Roaming Horses and Burros Act of 1971 along with many others, including Amerindians). He would miss them if removed and feels they are harmonious here. Film interviewed by Simone. Lives nearby.
Important Information for literature search:
Raptors wintering in the river corridor include Northern Harrier, Copper’s Hawk, Osprey, Red-Tailed Hawk, Sharp-Shinned Hawk, Prairie Falcon, Peregrine Falcon. Swainson’s Hawk and Ferruginous Hawk migrate through here in fall and spring.
Ecological threats include Tamarisk invasion, loss of water due to pumping and diversion. Risks to water quality come from herbicide and pesticide run off and pharmaceuticals in effluent waters. Uncontrolled human use of area disturbs nests and habitat. Much illegal dumping occurs and some damaging and dangerous accidental fires. Invasive Cowbirds are numerous and parasite nests of other birds.
The U.S. Army Corps of Engineers (Los Angeles District) was given an American Recovery and Reinvestment Act of 2009 contract to restore the Va Shly’Ay Akimel Salt River Ecosystem between the Salt River Pima-Maricopa Indian Community and Mesa, Arizona. This $645,000 contract funds Phase I involving ca. 2.5 miles along the river. It plans to restore the riparian ecosystem to support native vegetation and wildlife. This project runs a total of 14 miles between Granite Reef Dam and the SR 101 freeway.
The Salt and Verde Riparian Ecosystem is an IBA that is also germane to our project to protect the wild horses. It encompasses two rivers: the Salt and the Verde. The Salt River section of the IBA extends from Saguaro Lake’s Steward Mountain Dam along the riparian corridor of the Salt River west to the Verde River confluence. The Maricopa Audubon Society conducts the Salt and Verde River Christmas Bird Count each year that includes a portion of this IBA. This IBA contains ca. 1/3 of all Bald Eagle nest areas in Arizona. Nesting here are the Yellow-Billed Cuckoo, Southwestern Willow Flycatcher, Lucy’s Warbler, Abert’s Towhee, and the Common Black Hawk, all “Species of Conservation Concern”. Recreation uses, including boating and ATVs, disturb nesting birds. ATV’s impact flood-plain vegetation and cause erosion. Species on the Audubon list that I observed include: Gambel’s Quail, Northern Pintail, Common Merganser, Gilded (Northern) Flicker, Great Blue Heron, Great Egret, Southwestern Willow Flycatcher, Abert’s Towhee.
The 12-mile Salt River portion of the IBA is located in the Tonto National Forest, Mesa Ranger District, except the last 3 miles downstream. In the latter, the north side of the Salt River is within the Salt River Indian Reservation.
Fremont Cottonwood, Gooding’s Willow, and Arizona Ash are the dominant riparian species present in the flood plain habitat. In the lower section, Velvet Mesquite, Saguaro, Blue Palo Verde, Foothill Palo Verde, and Ironwood are the dominant upland trees.
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