Part 6

But over decades, centuries, or longer, the fulcrum of the seesaw moves: the larger environment changes, and the community and its constituent plants and animals must change with it or perish. Such changes may be climatic, as we saw with the formation of the Southwestern deserts; or it may be geologic, as with the rising and partial disintegration of the Rincon Mountains. The efforts of plant and animal species to meet such changes constitute in large part the story of evolution, for new environments spawn newly evolved forms of life. Evidence of such evolution we have seen in the plants of the Sonoran Desert, notably the giant saguaro cactus, whose prickly ancestor lived in the West Indies only 20,000 years ago.

Thus nature is ever-changing; and the inexorable rule for all living things is, “adapt or perish.” Before technological man enters the scene, the slow evolutionary process can keep pace with the changing environments, though here and there a species is dropped by the wayside. Generally, communities of living things reach new equilibria without serious disruption.

But what happens when man, with his machines and his passion for progress, institutes changes of a speed and kind and on a scale drastically different from those brought about by earthquakes, storms, shifting climates, and other natural phenomena? What happens to the living things that have adapted to the harsh desert environment when that environment is drastically altered?

the impact of man

Man has been a part of the scene in this region for several thousand years, but until recent times his influence on it was minimal. Only with the rapid technological development of the last century has man been able to make a major impact on this landscape. Thus the story of man, here as elsewhere, is a story of gradually accelerating power to change environments, a power that now threatens to destroy environments, and with them, man himself.

From carbon-14 dating in Ventana Cave, we know that man was here at least 12,500 years ago, in the Pleistocene age, a time that was cool and moist compared to the present. Living by hunting, he followed mammoths and other large mammals. As the climate warmed during succeeding millenniums, and these mammals became extinct, he came to rely more on plant foods. These hunters and gatherers necessarily had to live in small bands scattered over the land, since the plants and animals on which they depended were widely dispersed. By 300 B.C., they had learned from people to the south how to cultivate food plants, and had developed a sedentary way of life. About 2,300 years ago a group we call the Hohokam settled in the Salt and Gila River basins (including the Santa Cruz Valley). By A.D. 700 they had a well developed agricultural economy including extensive irrigation systems. Pottery fragments, projectile points, petroglyphs (rock carvings), and other evidence show that Hohokam villages existed for about 600 years in the eastern section of the monument along Rincon Creek and its tributary washes. Archeological work in the Tucson Mountain Section has indicated that this area was visited only temporarily by the Hohokam, for hunting, food gathering, and perhaps ceremonial purposes.

During the 15th century the Hohokam high culture vanished. Soils made salty from irrigation water and internecine warfare are suggested explanations.

When the Spanish explorer Coronado passed to the east of the Rincons in 1540, he found the Sobaipuri living there. The Pimas, descendants of the Hohokam, occupied the same basins the Hohokam had. To the west, in drier country, lived the Papago. These tribes, thought to be descendants of the Hohokam, lived much the same sort of life, practicing irrigation where surface water was available, hunting and gathering where it was not.

The period of Spanish rule, implemented by a series of missions, began in the Santa Cruz Valley about 1692, when the energetic Father Kino began his work among the Pima and Papago. The mission system concentrated the Indians in fewer places, brought Spanish and, later, Mexican settlers into southern Arizona, and introduced sheep, cattle, and goats. Although the new culture must have had some environmental effects, there is no evidence of drastic change. Grass was plentiful, and streams, including the Santa Cruz, remained marshy and unchanneled.

After the Gadsden Purchase of 1853-54, however, when the present boundary with Mexico was established and this area came into United States ownership, man’s impact on the land increased. Apache raiding had been a deterrent to settlement during the 18th and 19th centuries, but, after the Civil War, American soldiers got the upper hand and settlement increased. Following completion of the Southern Pacific Railroad to Tucson in 1879, a cattle boom began. The disastrous results of the livestock explosion of the eighties—overgrazing, soil erosion, and starvation of cattle—we have already seen in the story of the saguaro cactus. In 1890, a flood cut a deep channel in the Santa Cruz River, transforming it from a meandering, marshy stream to the usually dry incision one sees today. The arroyo cutting of this and many other rivers throughout the Southwest was undoubtedly due partly to increasing aridity, which reduced the plant cover and its water-holding capacity. But the erosion was probably triggered by overgrazing.

In the monument, we have already seen how grazing pressure, hunting, and predator control reduced ground cover and led to an upsurge of certain rodents and a decline in large mammals. But there have been other man-induced changes. For as long as there has been forest on top of the Rincons, there has been fire. Lightning-caused fire is a natural part of ponderosa-pine forest, every few years burning the litter and small trees and shrubs from the forest floor, and thus maintaining open stands of tall trees. But since 1908, when the Rincon Mountains came under protection of the Forest Service, U.S. Department of Agriculture (to be followed in 1933 by National Park Service, U.S. Department of the Interior protection), fires have been put out as fast as possible. This policy has resulted in a paradox. On the one hand, thickets of scrawny young pines and shrubs such as buckbrush have developed in many places under the tall pines. On the other hand, the accumulation of litter and low-level vegetation has provided fuel over the years for occasional very hot crown fires, which have been hard to control and which have burned large acreages. On top of the Rincons you can see several meadows that resulted from these fires. Only a few scattered trees and stumps remain in them to suggest the forest that once was there.

Ideally, national parks and monuments should be “vignettes of primitive America”—naturally evolved landscapes in much the same condition as when first seen by Europeans. In reality they are compromises—beautiful, wild, but still bearing the marks of human occupation. In Saguaro, as we have seen, fire control has produced a forest different from that known to the Indians who once lived here; grazing has depleted the ground cover; and hunting has removed the desert bighorn from its rocky haunts. In these days of burgeoning population, when human influence is affecting every natural landscape, environmental management becomes necessary to approach the ideal of naturalness. This may mean “prescribed burns” to return forests to their earlier state; elimination of grazing; or reintroduction of animals once native to a park. In the summer of 1971, after 2 inches of rainfall, natural burns (caused by lightning strikes) were allowed to run their courses.

Some or all of these measures may be taken in Saguaro, in order that future generations will know a piece of the Sonoran Desert as it was in Coronado’s time.

The realization of this goal, however diligently we work toward it, seems almost each day to become more difficult of attainment. These desert and mountain environments—which once seemed secure, needing only the continued protection afforded by their status as a national monument—are increasingly imperiled by the works of man. As the city of Tucson sprawls in all directions, the monument’s two divisions, islands in an encroaching sea of civilization, must withstand ever-accelerating hazards. Vandalism takes an increasing toll of the saguaros; housing developments creep toward the monument borders. Smog drifts over the fragile plant communities, threatening to choke them—as the polluted air from Los Angeles is already strangling forests in the distant San Bernardino Mountains.

A new awareness that the best-managed preserve cannot thrive independently of what is happening in the surrounding region only emphasizes the difficulty of the task. Saving the saguaros is inevitably tied to the problem of enhancing the quality of life and reversing the degradation of the environment—not only in Tucson but throughout the Southwest.

There is no time to waste. Only concerted effort by scientists, resource managers, and the community can assure that our grandchildren will be able to visit a Saguaro National Monument where coyotes howl under the moon, peccaries snort through the washes, and giant cactuses lift bristly green arms into a blue sky.

appendix

Suggested Reading

Arnberger, Leslie P. _Flowers of the Southwest Mountains._ Southwestern Monuments Association, Popular Series No. 7. Globe, Ariz. 1962.

Benson, Lyman D. _The Cacti of Arizona._ University of Arizona Press, Tucson. 1969.

Burns, William A. (ed.). _The Natural History of the Southwest._ Franklin Watts, Inc., New York. 1960.

Dodge, Natt N. _Flowers of the Southwest Deserts._ Southwestern Monuments Association. Popular Series No. 4. Globe, Ariz. 1961.

——. _Poisonous Dwellers of the Desert._ Southwestern Monuments Association. Popular Series No. 3. Globe, Ariz. 1964.

Dodge, Natt N., and Herbert S. Zim. _The Southwest._ Golden Press, New York. 1962.

Earle, W. Hubert. _Cacti of the Southwest._ Desert Botanical Garden. Phoenix, Ariz. 1963.

Jaeger, Edmund C. _The North American Deserts._ Stanford University Press, Stanford, Calif. 1957.

Kearney, Thomas H., Robert H. Peebles, and collaborators. _Arizona Flora._ University of California Press, Berkeley. 1960.

Krutch, Joseph W. _The Voice of the Desert._ William Sloane Associates, Inc., New York. 1955.

Milne, Lorus, and Margery Milne. _The Balance of Nature._ Alfred A. Knopf, Inc., New York. 1960.

Olin, George. _Mammals of the Southwest Deserts._ Southwestern Monuments Association, Popular Series No. 8. Globe, Ariz. 1965.

——. _Mammals of the Southwest Mountains and Mesas._ Southwestern Monuments Association, Popular Series No. 9. Globe, Ariz. 1961.

Patraw, Pauline M. _Flowers of the Southwest Mesas._ Southwestern Monuments Association. Popular Series No. 5. Globe, Ariz. 1959.

Phillips, Allen, Joe Marshall, and Gale Monson. _The Birds of Arizona._ University of Arizona Press, Tucson. 1964.

Schmidt-Nielsen, Knut. _Desert Animals: Physiological Problems of Heat and Water._ Oxford University Press, Inc., New York. 1964.

Sears, Paul B. _Deserts on the March._ University of Oklahoma Press, Norman. 1959.

Stebbins, Robert C. _Amphibians and Reptiles of Western North America._ McGraw-Hill Book Co., New York. 1954.

Storer, John H. _The Web of Life._ The Devin-Adair Co., Old Greenwich, Conn. 1960.

Sutton, Ann, and Myron Sutton. _The Life of the Desert._ McGraw-Hill Book Co., New York. 1966.

Underhill, Ruth. _People of the Crimson Evening._ Publications Service, Haskell Institute, Lawrence, Kans. 1951.

Common and Scientific Names of Plants

Agave—_See_ Amole Alligator juniper—_Juniperus deppeana_ Amole—_Agave schottii_ Arizona cypress—_Cupressus arizonica_ Arizona rosewood—_Vauquelinia californica_ Arizona sycamore—_Platanus wrightii_ Arizona white oak—_Quercus arizonica_ Aster—_Aster commutatus_

Barrel cactus—_Ferocactus wislizenii_, _F. lecontii_ Beargrass—_Nolina microcarpa_ Bladder-pod—_Lesquerella gordoni_ Bluedicks—_Dichelostemma pulchellum_ Blue paloverde—_Cercidium floridium_ Bluegrass—_Poa fendleriana_ Boxelder—_Acer negundo_ Bracken—_Pteridium aquilinum_ Brittlebush—_Encelia farinosa_ Buckbrush—_Ceanothus fendleri_ Bullgrass—_Muhlenbergia emersleyi_

Catclaw—_Acacia greggii_ Chain fruit cholla—_Opuntia fulgida_ Chihuahua pine—_Pinus chihuahuana_ Chokecherry—_Prunus virginiana_ Cinquefoil—_Potentilla subviscosa_ Cologania—_Cologania lemmoni_ Creosotebush—_Larrea tridentata_ Curly mesquitegrass—_Hilaria belangeri_

Desert chicory—_Rafinesquia neomexicana_ Desert Christmas cactus—_Opuntia leptocaulis_ Desert-marigold—_Baileya multiradiata_ Dogbane—_Apocynum androsaemifolium_ Douglas-fir—_Pseudotsuga menziesii_

Emory oak—_Quercus emoryi_

Fairy-duster—_Calliandra eriophylla_ Fiddleneck—_Amsinckia intermedia_ Filaree—_Erodium cicutarium_ Fishhook cactus—_Mammillaria sp._ Fleabane—_Erigeron arizonicus_

Gambel’s oak—_Quercus gambelii_ Goldenrod—_Solidago sparsiflora_ Goldfern—_Pityrogramma triangularis_ Gourd—_Cucurbita digitata_ Grama—_Bouteloua sp._ Groundsel—_Senecio neomexicanus_

Hairy grama—_Bouteloua hirsuta_ Hedgehog cactus—_Echinocereus sp._ Houstonia—_Houstonia wrightii_

Indian wheat—_Plantago purschii_ Indigobush—_Dalea sp._ Ironwood—_Olneya tesota_

Jointfir—_Ephedra sp._ Jojoba—_Simmondsia chinensis_

Lupine—_Lupinus sp._

Marigold—_Tagetes lemmoni_ Mesquite—_Prosopis juliflora_ Mexican blue oak—_Quercus oblongifolia_ Mexican pinyon pine—_Pinus cembroides_ Mexican white pine—_Pinus strobiforms_ Mock-pennyroyal—_Hedeoma hyssopifolium_ Mountain-mahogany—_Cercocarpus breviflorus_ Mountain muhly—_Muhlenbergia montana_

Netleaf hackberry—_Celtis reticulata_ New Mexican alder—_Alnus oblongifolia_ New Mexican locust—_Robinia neomexicana_ Nightblooming cereus—_Peniocereus greggii_

Ocotillo—_Fouquieria splendens_ Orange sneezeweed—_Helenium hoopesii_

Palmer oak—_Quercus palmeri_ Paper flower—_Psilostrophe cooperi_ Parry’s penstemon—_Penstemon parryi_ Peavine—_Lathyrus graminifolius_ Pencil cholla—_Opuntia arbuscula_ Phacelia—_Phacelia crenulata_ Pincushion cactus—_Mammillaria sp._ Pine dropseed—_Blepharoneuron tricholepis_ Pointleaf manzanita—_Arctostaphylos pungens_ Ponderosa pine—_Pinus ponderosa_ Pricklypear—_Opuntina engelmannii_ and others Puccoon—_Lithospermum multiflorum_

Quaking aspen—_Populus tremuloides_

Sacahuista—_See_ Beargrass Saguaro—_Carnegiea gigantea_ Scorpionweed—_Phacelia crenulata_ Screwleaf muhly—_Muhlenbergia virescens_ Shindagger—_See_ Amole Shrub live oak—_Quercus turbinella_ Sideoats grama—_Bouteloua curtipendula_ Silktassel—_Garrya wrightii_ Silverleaf oak—_Quercus hypoleucoides_ Skunkbush—_Rhus trilobata_ Snakeweed—_Futierrezia sp._ Snowberry—_Symphoricarpos oreophilus_ Sotol—_Dasylirion wheeleri_ Spanish dagger—_Yucca schottii_ Sprucetop grama—_Bouteloua chondrosioides_ Staghorn cholla—_Opuntia versicolor_

Tanglehead—_Heteropogon contortus_ Teddy bear cholla—_Opuntia bigelovii_ Texas bluestem—_Andropogon cirratus_ Triangle bursage—_Franseria deltoidea_ Turpentine-bush—_Haplopappus laricifolius_

Vine mesquite grass—_Panicum bulbosum_

Western yarrow—_Achillea lanulosa_ White fir—_Abies concolor_ White tackstem—_Calycoseris wrightii_ Wild carrot—_Daucus pusillus_ Wild-cucumber—_Marah gilensis_ Wild-heliotrope—_Heliotropium curassavicum_ Willow—_Salix sp._ Wolfberry—_Lycium sp._ Wolftail—_Lycurus phleoides_

Yellow paloverde—_Cercidium microphyllum_

Reptiles and Amphibians of the monument.

This checklist names reptiles and amphibians that have been seen, or that should occur, according to range maps and distribution records in important reference works, in the monument. Four of these species are found only in the Tucson Mountain Section; they are: desert iguana, desert horned lizard, western shovel-nosed snake, and sidewinder. An asterisk marks those species most commonly seen in the daytime.

The _desert_ (D) habitat is the rather flat or gently rolling terrain below 3,200 feet in elevation, as seen in the vicinity of the visitor center and the Cactus Forest Drive, and in the north and west portions of the Tucson Mountain Section.

The _foothills_ (F) habitat includes the area above 3,200 feet where the land becomes quite rocky and begins to ascend rather sharply on the Cactus Forest Drive and along Hohokam Road in the Tucson Mountain Section.

The _mountain_ (M) habitat is restricted to the Rincon Mountains above an elevation of 6,500 feet where one finds tall trees.

common name scientific name habitat AMPHIBIANS _toads and frogs_ Colorado River Toad _Bufo alvarius_ D F Great Plains Toad _Bufo cognatus_ D Red-spotted Toad _Bufo punctatus_ D F Woodhouse’s Toad _Bufo woodhousei_ D F M Couch’s Spadefoot _Scaphiopus couchi_ D F Western Spadefoot _Scaphiopus hammondi_ D F M Canyon Treefrog _Hyla arenicolor_ F M Leopard Frog _Rana pipiens_ D F M REPTILES _turtles_ *Desert Tortoise _Gopherus agassizi_ D F Western Box Turtle _Terrapene ornata_ D F Sonora Mud Turtle _Kinosternon sonoriense_ D F M Spiny Softshell _Trionyx ferox_ D _lizards_ Banded Gecko _Coleonyx variegatus_ D F Desert Iguana _Dipsosaurus dorsalis_ D Lesser Earless Lizard _Holbrookia maculata_ D F Greater Earless Lizard _Holbrookia texana_ D F *Zebra-tailed Lizard _Callisaurus draconoides_ D F *Collared Lizard _Crotaphytus collaris_ D F Leopard Lizard _Crotaphytus wislizenii_ D F Short-horned Lizard _Phrynosoma douglassi_ F M Desert Horned Lizard _Phrynosoma platyrhinos_ D *Regal Horned Lizard _Phrynosoma solare_ D F *Side-blotched Lizard _Uta stansburiana_ D F *Tree Lizard _Uta ornata_ D F M *Desert Spiny Lizard _Sceloporus magister_ D F Clark’s Spiny Lizard _Sceloporus clarki_ D F M Eastern Fence Lizard _Sceloporus undulatus_ F M *Western Whiptail _Cnemidophorus tigris_ D F Spotted Whiptail _Cnemidophorus sacki_ D F Arizona Alligator Lizard _Gerrhonotus kingi_ M *Great Plains Skink _Eumeces obsoletus_ D F *Gila Monster _Heloderma suspectum_ D F _snakes_ Western Blind Snake _Leptotyphlops humilis_ D F Arizona Coral Snake _Micruroides euryxanthus_ D F M Regal Ringnecked Snake _Diadophis regalis_ F M Western Hognose Snake _Heterodon nasicus_ D F Spotted Leaf-nosed Snake _Phyllorhynchus D F decurtatus_ Saddled Leaf-nosed Snake _Phyllorhynchus browni_ D F Coachwhip _Masticophis flagellum_ D F Sonora Whipsnake _Masticophis bilineatus_ D F M Western Patch-nosed Snake _Salvadora hexalepis_ D F Mountain Patch-nosed Snake _Salvadora grahamiae_ M Glossy Snake _Arizona elegans_ D F Gopher Snake _Pituophis catenifer_ D F M Compton Kingsnake _Lampropeltis getulus_ D F Sonora Mountain Kingsnake _Lampropeltis pyromelana_ M Long-nosed Snake _Rhinocheilus lecontei_ D F Black-necked Garter Snake _Thamnophis cyrtopsis_ F M Mexican Garter Snake _Thamnophis eques_ D Checkered Garter Snake _Thamnophis marcianus_ D F Western Ground Snake _Sonora semiannulata_ D F Western Shovel-nosed Snake _Chionactis occipitalis_ D Banded Sand Snake _Chilomeniscus cinctus_ D F Mexican Black-headed Snake _Tantilla atriceps_ D F Plains Black-headed Snake _Tantilla nigriceps_ D F Sonora Lyre Snake _Trimorphodon lambda_ D F Night Snake _Hypsiglena torquata_ D F M Western Diamondback _Crotalus atrox_ D F Rattlesnake Sidewinder _Crotalus cerastes_ D Black-tailed Rattlesnake _Crotalus molossus_ F M Tiger Rattlesnake _Crotalus tigris_ F Mohave Rattlesnake _Crotalus scutulatus_ D F Arizona Black Rattlesnake _Crotalus viridis F M cerberus_

Birds of the monument

This checklist is based entirely on written records of observations of birds seen in the monument. Names are in accordance with A.O.U. Checklist of North American Birds, 5th edition, 1957. (See checklist of reptiles and amphibians for description of habitats.)

key to symbols: D desert habitat F foothill habitat M mountain habitat * species most often seen at lower elevations s summer resident w winter visitor p permanent resident t transient visitor