Casa Grande Ruins Casa Grande Ruins National Monument, Arizona: A Centennial History of the First Prehistoric Reserve 1892 - 1992

In the latter half of the nineteenth century, human activity began to alter the Gila Valley landscape with an outcome that left Casa Grande Ruins National Monument as an island of natural desert growth in the midst of an agricultural community. Outside pressures from ranching followed by twentieth century farming and urban development have taken their toll on the monument flora and fauna and continue to threaten further degradation of the monument's natural vegetation and wildlife. Consequently, in the 1980s, the major issues of monument management have changed from ruins preservation to protection of the natural habitat.

A. The Natural Setting

In the centuries following the Hohokam abandonment of Casa Grande, desert vegetation and grass recaptured the land. Travelers in the last half of the nineteenth century could never have envisioned the modern-day scene of this area. At that time nearly all who passed through the valley were impressed with the desert growth and in particular with the tall mesquite. Henry Hanks, who accompanied some New Jersey geologists in 1879, noted that the mesquite hid the Great House until it had been nearly reached. Even by that date, however, the human element had begun to make a change. [1]

In 1869, when Ralph Norris surveyed the subdivision lines in Township 5 South, he noted that Section 16 had a cover of mesquite, greasewood, and grass. Norris thought that much of the township had an appearance of having been cultivated and, as a result, contained a large supply of "grammon" grass. Grass frequently becomes the first invader of previously disturbed soil and thereby controls the disbursement of other vegetation. Periodically, along the banks of the Gila, Norris found that Mexican families had already settled and were cultivating fields using water diverted from that river. By the early I 870s, however, the abundant grass attracted ranchers. Charles Clark, who visited Casa Grande in 1873 recorded the existence of Decker's ranch buildings along the Gila just north of the ruins. Although suffering occasional setbacks from drought, cattle ranching prospered in the monument area for about fifty years. Livestock, wandering over open range, proved to be a destructive nuisance to the ruins. The early custodians requested funds to fence the prehistoric remains to keep cattle away from them. They reported that livestock had damaged the ruins both by rubbing against them and walking over the mounds. Although the custodians only expressed a concern about ruins damage, the cattle also destroyed the natural vegetation. Cattle would be attracted to the shade provided by the taller ruins. As a result, the surrounding vegetation suffered from grazing and trampling. Frank Pinkley reported in 1902 that the range cattle had consumed all the forage within 100 yards of the Great House. Such intensive grazing on the monument not only destroyed the grass, but had an effect on other natural vegetation. The lack of grass allowed mesquite and creosote bush to spread and dominate the other vegetation. Consequently, some change would have begun to occur in the monument flora by the later part of the nineteenth century. Despite livestock damage to the natural vegetation, a 1912 description stated that the desert around Casa Grande "is rather well covered with trees, brush, shrubs, and in the spring a large variety of wild flowers. Among the trees, shrubs, and brush, are the mesquite, catclaw, creosote bush, salt bush sometimes called sage brush. Cactus is not very prominent immediately surrounding Casa Grande ...". Animal and bird life, however, were quite abundant. [2]

Although livestock grazing may have harmed the monument vegetation, the development of irrigated land and a population center on the monument's boundary led to even greater damage to the flora and fauna. The first sign that would lead to an even greater change in the monument's vegetation appeared in the 1880s. Farmers began to settle along the Gila River some twenty miles upstream from Casa Grande and, by building crude diversion dams, they obtained some of its water for irrigation. On their land they planted fruit trees, grapes, cereal grains, and alfalfa. In 1889 the Pinal County Board of Supervisors advocated that a permanent dam be built at the Buttes area, some fifteen miles east of Florence, to provide a water storage reservoir. The supervisors concluded that water from this source could be used to irrigate the whole Gila Valley. At the time that this promotional tract appeared, men had already begun to dream of constructing a permanent dam at that site. Irrigation water from a storage reservoir was not the only source of moisture. By the early part of the twentieth century, farmers realized that an immense amount of water lay at shallow depths under the whole Gila Valley. In 1916 in an effort to attract more farmers, the Pinal County Commissioner of Immigration wrote that many wells furnished a plentiful supply of irrigation water. [3]

Although the early farmers focused their irrigation efforts to the east of Florence, the arrival of more and more settlers, combined with the approval of the Coolidge Dam to store Gila River water, soon brought people to cultivate the land around Casa Grande. The approval of the San Carlos Irrigation District in 1924 led Frank Pinkley to write that "this irrigation district will surround our monument and the time may come when we will have the only bit of typical desert land in this part of the valley." [4]

In 1925, R. J. Jones, a Phoenix businessman, purchased eighty acres of land along a newly constructed line of the Southern Pacific Railroad and plotted it into a town site just southeast of the monument boundary. He named it after President Calvin Coolidge, who occupied the White House at the time. Many young married couples purchased property there. As a future omen, one of the first buildings constructed in the town was a cotton gin. When part of the boundary and subdivision lines of Township 5 South were resurveyed in 1928, the surveyor, Dupree Averill, noted that, in scattered areas throughout the township, land had just begun to be improved for irrigation. [5]

Once started, the development of irrigated land spread rapidly. In 1929, Edna Pinkley wrote that the desert around Casa Grande was disappearing quickly to be replaced by cotton, alfalfa, grapes, and lettuce. The following year, during a visit to the monument, Charles Peterson echoed Pinkley's earlier thoughts. He wrote that irrigation made possible by the Coolidge Dam would leave the monument acreage as an isolated area of desert flora among cultivated fields. It did not take long for Casa Grande to become a desert island. C. P. Russell observed in 1932 that agricultural development had affected the monument on all sides making it a bit of native desert preserved. Soon, spring winds carried soil from surrounding fields being prepared for cotton planting. These storms carried dust across the monument. [6]

Settlers continued to be attracted to Coolidge and its surrounding area after 1930. The period of greatest growth came between 1930 and 1945 as more and more irrigation took place. As it turned out, the storage reservoir behind Coolidge Dam could not supply sufficient water for an entire growing season. Consequently, the Indian Irrigation Service, San Carlos District, and farmers all drilled wells to obtain water when the reservoir ran dry. Pumping more and more water rapidly lowered the water table. This situation, in turn, caused farmers to drill their wells deeper. In a time of drought during 1947-48, the water shortage led to a sharp drop in the population growth rate. Rumors spread that the state legislature intended to control water use. Consequently, land speculators began to sink as many wells as possible before any regulation could take affect. When pumping began from these new wells in the spring of 1948, the water level in the monument well fell by ten feet. In the next year it had dropped an additional thirty to thirty-five feet. As usual, the state did nothing to regulate the water problem. Testimony at public hearings in June 1951 gave evidence that ground water was being removed thirty-seven times faster than it was being replaced. The state land commissioner stated that there were 539 wells functioning in the Gila and Santa Cruz River ground water basin. If that were not bad enough, he reported that he had received 395 new notices of intent to drill wells. It would take years and the abandonment of some land before any regulation was placed on the number of wells. [7]

B. The Effect of Neighboring Agriculture on the Monument

Because of its small acreage, the monument land could never encompass a desert ecosystem. In the days before the development of modern agriculture, its desert vegetation blended with the surrounding area to provide an ecological niche for many birds and animals. Even the period of open-range cattle grazing did not seem to harm the wildlife. In 1924 George Boundey wrote that a faucet on the well pipe was allowed to drip water into a basin. The presence of water attracted all sorts of wildlife. He recounted that he had seen "ravens, hawks, mockingbirds, desert horned larks, hummingbirds, Sonora pigeons, ring necked pigeons, cactus wrens, yellow shafted flickers, thrashers, phainopeplas, cardinals, tanagers." Tracks near the basin indicated the presence of great horned owls, cottontails, jack and antelope jack rabbits, kangaroo rats and mice, fox, bobcats, and coyotes. He even saw a red racer snake and a gila monster drink the water. [8]

As a small piece of habitat, the monument was further hampered from serving any balanced natural function starting with the 1930s. Surrounding the monument with irrigated agricultural land destroyed the outside native vegetation and reduced the animals' natural habitat. To survive, smaller mammals were forced from the surrounding area onto the monument where overcrowding put pressure on the natural community. Enclosing the monument with a fence, as was done by 1934, prevented the free range of larger mammals. Thus somewhat protected, the smaller mammals multiplied. By the mid-1930s a serious rabbit overpopulation caused the destruction of young plants, especially mesquite. Without the benefit of natural checks and balances the monument vegetation cover suffered greatly. [9]

Starting in the 1930s destruction of the natural vegetation cover increased. This annihilation became especially noticeable with the death of the mesquite and diminished numbers of salt bush. In August 1936 monument personnel noticed that an infestation of bugs and worms had attacked mesquite trees. These insects were judged to be quite harmful. Without funds, however, the trees went untreated. Following circulated reports of this attack, two Park Service biologists came to Casa Grande in January 1937 to examine the mesquite. C. P. Russell and A. E. Borell concluded that soon no mesquite would exist on the monument. They judged that all of the existing mesquite were doomed because of their age combined with a mistletoe infestation and insect attacks. Russell and Borell also decided that the rapidly lowering water table could be responsible for the deterioration of the mesquite. Most important, however, there was a total lack of natural mesquite reproduction. An abnormally large rabbit population on the monument probably prevented new growth, but the lowered water table, they felt, could also be a cause. In the meantime, Russell and Borell thought that one of two courses of action could be used with the existing mesquite. Either the trees could be trimmed to keep them free of insects and other parasites during their remaining life or nature could be allowed to take its course. In any case, the removal of affected tree parts would not promote growth or reproduction. The solution to develop new mesquite trees involved a transplant program combined with irrigation. [10]

Dr. E. P. Meinecke came to the monument in the fall of 1937 to give a second opinion on the mesquite problem. He observed that while most mesquite were in decline, a few were sound and bright. The mesquite, Meinecke decided, had been in decline for a number of years. He listed three potential causes for mesquite deterioration. Part of the cause came from an infestation of mistletoe which hung heavy from the tree branches. A lowered water table, as the result of pumping for agricultural irrigation, aided the decline. Another consideration ascribed the damage to a flat-head borer (Chrysobothris octorola). Meinecke wrote that more had to be learned about the damage caused by the borer before any decision could be made on its effect. He observed that the borer only lived in the bark of dead or injured trees, so it possibly did not contribute to the death of the mesquite. In his judgement, Meinecke concluded that the lowered water table had the greatest impact on the mesquite. Another problem was the lack of mesquite reproduction, which he felt was mainly due to an overpopulation of rabbits that had found a safe haven on the monument. Another consideration came from the fact that the lower branches had been pruned from many of the trees. (Men involved with several depression-era programs had trimmed mesquite both as make work and at the recommendation of Russell and Borell.) Meinecke stated that mesquite needed to have lower branches because it was the shade from these lower branches that permitted mesquite seedlings to develop. Consequently, he recommended that pruning cease. [11]

Further studies were not undertaken on the mesquite problem and the trees slowly died. Superintendent Bicknell reported in January 1953 that conditions remained the same for the mesquite since he had first reported on them in 1936. Nearly all of these trees had died by the 1960s. An article in a 1971 issue of the Great Basin Naturalist concluded that, although data were incomplete, the mesquite decline resulted primarily from a lowered water table and a mistletoe infestation. Age, insect infestation, and lack of reproduction were considered secondary factors. All the mesquite, except for some around the visitor center/housing areas that are watered, have died. The death of the mesquite caused a change in soil moisture retention with the result that salt bush have also begun to decline. This same phenomenon created a favorable environment for the creosote bush and this vegetation moved into areas once occupied by the salt bush. Consequently, "the only bit of typical desert land" that Frank Pinkley thought the monument would support, has not occurred. The monument land no longer contains an area of "typical" desert. Because of the agricultural development around the monument's boundary, it has become an area on which some desert plants grow. [12]

Aside from a lowered water table, neighboring agriculture has potentially had other effects upon the monument flora and fauna. Beginning in the 1950s, farmers began to spray herbicides and pesticides on their fields from airplanes. By the late 1950s, just before harvest, cotton fields received an aerial spraying of a defoliant [Agent Orange?] to make it easier to pick the cotton. With each of these spray applications, planes undoubtedly flew over the monument releasing some spray. On other occasions spray would have drifted onto the monument as it was applied to neighboring fields. Some effects of these sprays on the monument's plants and animals have been determined, but a comprehensive study has yet to be conducted. [13]

C. Monument Management of Natural Resources

During the period when Casa Grande was a reservation, natural resources were not taken into consideration. For most of the years after 1918, when Casa Grande became a national monument under the Park Service administration, natural resource management was considered to be secondary to cultural resources. After all, managers reasoned, the monument was established to preserve its prehistoric ruins and not its desert life. Although there was some interest by the 1930s in interpreting natural history, little was accomplished. Visitors who wished to learn about desert flora and fauna were directed to Saguaro and Organ Pipe National Monuments.

For good or bad, some consideration was given to wildlife by the early 1920s. George Boundey noted that water was allowed to drip into a basin for birds and animals. No concept of an ecosystem or balance of nature, however, applied at the time. Occasionally in the early 1920s, some birds and animals were thought to be a nuisance with the result that an effort was made to reduce their population. At the same time other birds and animals were protected. In 1924 Boundey wrote about protecting red and black racer snakes mostly because they lived off the bats that resided in the Great House. On one occasion Boundey tried to shoot a roadrunner that had attacked and killed two adult thrashers. Another time he did shoot a male roadrunner, but he regretted this action when he heard the mate's mourning calls. Pinkley was delighted when Great Western Horned owls returned each year to nest in the Great House because their presence provided an attraction for visitors. [14]

In the fall of 1932, soon after Pinkley hired Bob Rose as a park naturalist in his Southwestern Monument's office, Rose decided that he wanted to develop a more comprehensive education program for the Southwestern Monuments. At Casa Grande, he wanted to reduce the emphasis on cultural resources and provide a more balanced picture with natural resources. At the same time, Rose wanted to develop a scientific study program and reference collections on mammals, birds, reptiles, insects, and botanical material. Rose's desire was reflected in the 1934 Six-Year Program. The authors of that plan expressed the need for the development of a natural resources program through which visitors could receive information on desert growth. [15]

Despite grand desires, only a minor natural resource plan developed at Casa Grande during the 1930s. A bird banding program, which was conducted for several years, began in March 1935. This activity led to thoughts of banding or marking nocturnal animals, but no action was taken to start such a study. An annual wildlife census, based upon casual sightings, began in the late 1930s and lasted into the 1950s. Few larger mammals, such as coyotes, were seen, but each year an abundance of cottontails and jackrabbits were reported. [16]

In 1941 the National Park Service began a program to exclude exotic plants from park areas. Hugh M. Miller reported that although a survey had been made for exotics, the only such plants at Casa Grande were flowers and shrubs that existed in small plots in the residential area. The search for exotic plants evidently was not taken seriously because the very next year a new grass was reported to be growing in great abundance on the monument. Tentatively identified as Australian Bunch Grass, these plants produced seed in such large amounts that a prediction was made that it would soon cover great sections of the monument. [17]

An effort began in 1941 to artificially encourage the regeneration of the monument's diminished vegetative cover. A Soil and Moisture appropriation was used to develop a soil conservation program. By this scheme, a system of contour furrows and low dikes were located in strategic places to prevent moisture runoff. This project evidently had little effect to renew the vegetation, but, by 1952, it was judged to have been of aid in the prevention of soil erosion. [18]

Although Mexican Free-tail bats had inhabited the Great House for many years, in the 1940s they seemed to increase in numbers. A bat count on August 31, 1944, produced a figure of 5,330 bats flying from the Great House in a period of nineteen minutes. The bats were deemed to be a nuisance since their droppings stained the Great House walls and created an offensive odor. Bats also contributed to enlarged cracks in the Great House walls since they lived in these fissures. In addition the bats attracted red and black racer snakes which used them as a source of food. These snakes sometimes frightened visitors as they stalked their prey. On one occasion, a ranger, while guiding a women's group through the Great House interior, directed their attention to the beam holes in the upper part of a room at the moment a black racer swung from a brace and pulled a bat from its hiding place. The startled women stood motionless until the snake began to devour the bat. Forgetting all interest in the ruins, the women rapidly departed the building. [19]

By mid-1946, Casa Grande's Acting Custodian, Peter Schuft, sought a means to end the bat problem. While he hoped to obtain some sonic device to drive the bats from the Great House, the head of the Chemical Products Company in Phoenix made a $25 bid to exterminate them. John Davis, the acting associate regional director of Region Three, wanted more information on any elimination program. He thought that, because the bats were mostly beneficial, the Park Service director needed to make a decision before any action was taken. That fall, National Park Service Director Newton B. Drury consented to have the bats driven from the Great House by using sonic sound waves. Such an instrument evidently could not be found because the bats were not removed. [20]

Bats again became a subject for extermination in 1948. On this occasion the Regional Naturalist, Natt Dodge, told Casa Grande Custodian Bicknell that it was against the law to rid an area of wildlife. He quoted Chapter 1, Section 2.9 of the rules and regulations which stated:

The parks and monuments are sanctuaries for wildlife of every sort, and all hunting, or the killing, wounding, frightening, capturing or attempting to kill, wound, frighten, or capture at any time of any wild bird or animal, except dangerous animals when it is necessary to prevent them from destroying human lives or inflicting personal injury, is prohibited. [21]

Toward the end of 1948, the National Park Service Assistant Director countered Dodge's pronouncement by citing Section 4.655, Part 4, Subtitle A, Title 43 of the Code of Federal Regulation dated August 13, 1947. This regulation gave the National Park Service authority to control animals around historic and prehistoric structures. It stated that animals could be destroyed for the following reasons:

1.) habitually destructive to buildings or property

2.) if they were injured, crippled or decrepit animals

3.) rodents hazardous to human health and safety

4.) rodents doing injury to shade trees or other vegetation

5.) exotic and domestic animals that have reverted to a wild state. [22]

Although no National Park Service action was taken against the bats, their days were numbered at the monument. In 1952 Park Service Director Conrad Wirth decided that Title 43 of the Federal Regulation cited by the Assistant Director in 1948 did not give the National Park Service authority to destroy bats. Wirth's determination did not matter because, by that date, fewer bats resided in the Great House walls. Spraying the area cotton fields had so reduced the insect population that the bats had either begun to move to other regions or had died from the poisoned insects. By October 1956, bats no longer lived on the monument. Without bats, fewer red and black racer snakes were sighted. [23]

Birds as well as bats were affected by the insecticide sprayed on neighboring agricultural fields. By the early 1960s the number of cactus wrens living on the monument had been greatly reduced and owls no longer lived in the Great House. Crop spraying was given as the reason for this phenomenon. For years, sparrows had been discouraged from entering the Great House by the owls. With the death or departure of the owls, great numbers of sparrows took up residence in that building. In 1964 monument personnel sprinkled mothballs around the Great House in an effort to get rid of those birds, but this measure did not succeed. It was thought that they should be trapped although no effort was made to do so. In 1968 Roy Reaves gathered the debris which he thought had been sloughed from the south room walls in the Great House by the sparrows. On the basis of that sample, he figured that these birds had knocked as much as 215 pounds of material from the wall. In the following year, he set out to control the sparrows by destroying their nests. This measure had some effect as fewer birds were seen in the structure and forty-five percent less debris was gathered. This effort to control the sparrows ended in 1970 when Reaves left the monument. In the present day the number of these birds roosting in the Great House or the protective roof does not seem to pose a problem. [24]

By 1980 the destruction of the monument's natural resources took on a greater concern. In that year, Casa Grande Superintendent Sam Henderson proposed to have an inventory made of the monument's flora and fauna along with a study of the effects of the dropping water table. Nothing came of his proposal. Then, in 1986, the newly arrived superintendent, Donald Spencer, placed a great emphasis on the monument's natural resource management. He made the formulation of "a long-range policy based on sound research for the preservation or restoration of the desert environment that would be appropriate and pertinent to the prehistoric scene" one of his management objectives. As a first step, he proposed to develop a Resource Basic Inventory (RBI) of the natural resources. With that information, Spencer felt that the effects of crop spraying and the dropping water table as well as other outside threats could be determined and action taken against them. Consequently, in 1986 he contracted as Phase I of the RBI to have the monument's vegetation inventoried. It was completed in 1988. An inventory has also been completed for birds, but a study on insects has not begun. Any attempt to return the monument to the only bit of typical desert land in the area will require enormous effort. At the same time some exotic plants like the Thistle Bush, which appeared on the monument in 1990, will need to be eradicated. [25]

In the future, outside pressure from agriculture will probably diminish, but less agricultural pressure will only be replaced by that from an urban community. Developer Sam Capon has proposed to construct a shopping mall, condominiums, single-family residences, and apartments across Highway 87 on the monument's east side. William Costello wishes to install a trailer park across from the monument's northeast corner. Another trailer park is proposed for part of the monument's south side. Finally, the Butterwick Enterprises of Denver, Colorado is seeking to build single-family dwellings on the monument's west side. Casa Grande's natural landscape will survive but only as an area containing desert plants.