By Walt Anderson
Four decades ago, I was a grad student in the School of Natural Resources at the University of Arizona in Tucson. Well before Arizona gained its strong reputation as a hotspot for American birding, there was a small community of birders who sought out the neotropical specialties that crossed the border and the eastern vagrants that popped up now and then in desert oases. There were seasoned experts like Gale Monson, whose knowledge of Southwest birds was encyclopedic, and ragtag graduate students like Carroll Littlefield, an expert on Sandhill Cranes, and Ted Parker, later considered by many as the superstar of birders and field ornithologists. There was none of the competitive, obsessive listing that later infected the birding world, a narrow-minded focus on seeing and ticking off species as fast as possible, the interest in each bird satisfied by a mere checkmark. No, these were naturalist birders, keen observers who sought to learn about the entire ecosystems in which birds were a part. Where a bird nested, what it ate, how it migrated or molted—such were the questions that occupied the curiosities of this generation of field biologists.
Whenever possible, we would load up a tank of gas at twenty-some cents per gallon and take off to one of our favorite oases, ostensibly to bird, but even more so to explore wild places and experience the joys of discovery in nature. Often our paths took us through the dusty border town of Douglas, Arizona under the appalling smokestacks of Phelps Dodge, then likely the largest single point-source of pollution in the Southwest, if not America as a whole. Continuing east along teeth-chattering gravel roads, we passed through the “malpai” badlands of rocky hills, creosote bush, ocotillo, and occasional flash-flood-prone desert washes. We’d pass the old ranch of Texas John Slaughter, where we’d stop to glass for whistling ducks, Neotropic Cormorants, Vermilion Flycatchers, and other oasis birds drawn to the artesian springs there (later much of this became the San Bernardino National Wildlife Refuge established primarily to help save native fishes of the Rio Yaqui watershed).
Our final destination lay at the end of the road just into New Mexico right where that state intersects with Arizona and Sonora: a green finger of Mexican riparian woodland, Guadalupe Canyon. We would stop up at the Magoffin ranch house to pay our respects and get their generous permission; then we’d explore the main canyon of large cottonwoods and sycamores and venture up thorny side washes for arid-adapted specialties. At night, we would listen and watch for the Ridgeway’s Whip-poor-will (now called Buff-collared Nightjar), one of the species that barely entered the United States at this point.
We were certainly aware of the proximity of Mexico, but only because we could count birds seen on this side of the weak barbed-wire fence for our U.S. list. At night as we lay in sleeping bags under the canopy of trees and the overarching dome of stars in an unpolluted sky, we might awaken to the footsteps and breathing of men, usually alone or with one companion, heading north to work, seeking employment opportunities that were unavailable south of the border. We might meet them at dusk or in early morning, where a polite exchange of “Buenos Dias” or “Hola” along with shy smiles would be the extent of our interchange.
One morning, three of us decided to step over the loose fence and walk south. We had absolutely no idea of what we would find, and the fact that this was “foreign land” made it all the more exciting. For hours we walked through grasslands along ridges, discovering an old cobblestone road that we followed for several miles. There were signs of cattle, but we encountered no people. Finally we descended off the high ridges into a substantial canyon, where a perennial stream meandered under stately cottonwoods. Some cottonwoods had the unmistakable beveled cut marks that indicated beaver presence. We were stunned—beavers had been trapped out in southern Arizona years before. Could this mean that beavers had survived the onslaught of the trappers in La Frontera de Sonora?
That canyon, I soon learned, was Cajon Bonito. If dry Guadalupe Canyon was a birding hotspot, this live stream and its gallery forests were a biodiversity inferno. The memory of it haunted my imagination for years.
That was in the early 1970s. More than twenty years later, I accompanied ecologist Mark Briggs into Sonora to join other conservationists as guests of Josiah and Valer Austin, new owners of a ranch on Cajon Bonito. Austins represented a new breed of ranchers, people who could see beyond commodity production into visions of restoring healthy landscapes, and we were there to see what they were doing and to offer any insights or advice we might have.
For several days we explored the canyon and its watershed—the Sierra San Luis and other rugged mountains. We were thrilled to learn that here lived eight native species of fishes and no exotics (currently, Aravaipa Canyon is the best in Arizona with seven). There was sign of the beavers, descendants of those present in the early 1970s. Some of us immediately began to think of this intact population as the potential source for beaver reintroductions elsewhere in the Southwest, as it is axiomatic that using a local source population takes advantage of local adaptedness.
We saw that Austins were going to close use of the creekbed as a road (it had been the main highway between northern Chihuahua and Sonora for years, and evidence of past heavy use—even of trucks and buses—was still apparent). Riparian areas with removal of stressors like cattle have the capacity to recover quickly, and if Cajon Bonito was considered “one of the most-intact, low-desert watercourses in the American Southwest” (Rinne and Minckley 1991), then its future under Austins’ management looked rosy indeed.
As the biologists and land managers dispersed after several enlightening days in Cajon Bonito, the Austins invited me to linger a bit longer and to go back to Arizona with them. We were thus able to hike downstream to an enchanting side canyon known to them as “The Grotto,” where a waterfall spills over a basalt cliff into a clear pool, where maidenhair ferns cling to the dripping rocks and large sycamores and ash provide perpetual shade.
As we drove back toward Agua Prieta where we could cross back into the United States, I told the Austins about the walk from Guadalupe Canyon to Cajon Bonito twenty years before and about the discovery of the beavers. When we were going through a vehicle checkpoint, we ran into the couple who owned Rancho Puerta Blanca, the “White Gate Ranch” that must have been our point of entry into Mexico all those years before, a time before Mexico built the border highway that now lies north of the cajon. At dinner in a small café in Agua Prieta, Josiah urged me to tell my story to the rancher. His face lit up when I mentioned the beavers, and he said, “Oh, yes, Chappo’s father brought those in from Canada in the 1940s.”
A few hours before, the ecologists I had been with were enthusiastically considering using the Cajon Bonito beavers as a source of animals for transplanting, repopulating beavers across their historical range. The assumption was that these were native animals. I had just learned, entirely by chance, that today’s Cajon Bonito beavers were of Canadian stock, doing just fine, thank you, despite the dramatic differences in climate from their homeland.
It’s all too easy to see a landscape in its current state without knowing enough about its historical context. The deep arroyo that forces us to detour appears permanent and timeless, when, in fact, a few hundred years ago, native fishes spawned in the marshlands created by beaver dams on this very spot. The stand of straight pines that cloaks the slopes today may be an artifact of past logging and subsequent fire suppression. The dense thickets of mesquite and prickly pear may bear little resemblance to the grasslands that preceded them. And the ecosystems that we view today, those to which we assign value as future conservation lands, may be mirages, as well. I have to remind myself as I think about climate change, about evolving land status in the dynamic borderlands, that “the future’s not what it used to be.” At the same time, the past slips into history; unless we are aware of it, we may be groping in the dark, armed with good intentions but handicapped by the limitations of our knowledge.
As a natural historian, I hope to pass along some of the accumulated wisdom and experience of those who have gone before, to provide some of the clues that will help one decipher the codes of the landscape. I want to share some of the learning rules of the culture of ecological science and conservation biology, guidelines that will permit extrapolation and further personal discovery. Though the Sky Islands of the US/Mexico borderlands are a specific and unique region, the naturalist’s ways of knowing are not geographically bounded. Learning to navigate these islands will help one to sail meaningfully on other waters.
There are patterns on the land, and many of these reflect somewhat predictable underlying causes. Climate, geology, latitude, and soils all influence what can live here and how things go about living here. Biological factors, such as competition, predation, disease, parasitism, and social systems, are additional determinants of the patterns of life. Humans certainly are among those biological factors, and their (our) influences have at times been highly significant.
“History” is of course, more than a mere chronology of events. There are elements of chance that have influenced these islands just as surely as physical and evolutionary principles have. The arrival of a waif from across the oceanic barrier or the impact of a rare storm or intense fire on the survival of the inhabitants of a small habitat island can set into motion processes unique and unrepeatable. What unfolds is contingent upon what happened before. Continental shiftings, the buckling of crustal surfaces on massive scale, the advances and retreats of a vast Pleistocene Lake or the arm of a shallow sea, the intrusion of heavy metals into certain rocks, the formation of the Bering Land Bridge, the rapid spread of a particular technology — all these, unpredictable in any precise way, have shaped the Sky Islands that we see today and contribute to the context within which the Sky Islands will continue to evolve. Remove copper or Apaches or the arbitrariness of an international boundary, and this landscape today might be quite different.
Natural history is a way of knowing, a way of trying to fathom how the world works. Direct powers of observation are considered within a theoretical framework and in light of the circumstances of history to seek explanations and understanding. Details, unique particularities, are examined and absorbed to become tiny pixels of information. Given enough pixels and a way of organizing them, one may eventually develop a fairly coherent picture of a larger whole. Some pixels may, in fact, help generate others, a form of self replication that may sharpen the resolution of the total image.
Just as a photograph is a representation of something else, at least a step away from the object or feeling it is meant to evoke, any “big picture” of the ecologist or natural historian is not the precise equivalent of “the real world.” We are limited by both our sensory and processing equipment. We do not record nature perfectly; we interpret it.
Our interpretations are, in fact, colored by the kinds of questions we ask and by how we conduct our inquiries. If the current belief of our society is that fires are destructive forces that must be controlled, we may be blind to the restorative powers of fire in an ecosystem in which organisms evolved with frequent, low-intensity fires. When a paradigm shift occurs and we embrace fire as a management tool, we may overlook other ecological effects and end up with “unexpected consequences” (a handy euphemism to cover our “blind spots”). In fact, awareness of the fragmentary nature of even our best models of nature should encourage us to move slowly and with humility. “Land management” may be just as oxymoronic as “military intelligence.”
Yet both governmental and private organizations are often charged with just that: land management. In truth, we all do it. Our personal choices — picking a site for home building, creating a lawn or garden, selecting our pets, buying our produce or beef, recycling our wastes (or not), supporting our charities, paying our taxes, electing our leaders, driving our cars, and paying our lawyers — all result in land management consequences. The least we can do is try to become aware of the implications of our actions within and beyond our home region.
Natural history is not something we study in the grassland or chaparral or high on the mountaintop, wonderfully esoteric nature worship that we leave behind with Pan in the pansies when we return to our homes and families. Oh, no. A study of the Sky Islands would be incomplete, even deceptive, if we did not consider the cows, the cats, the interstate highways, the second homes, the introduced bullfrogs and starlings, and even economic policies as manifest in NAFTA. The naturalist cannot hide behind a thicket of wild roses bursting with activity of butterflies and songbirds. Discussion of parasitism and predation cannot stop with the gall wasp and the preying mantis as examples. Humans function in these roles, as well.
The Sky Islands region may have low human densities (at the moment), but the suburban growth of Tucson, the groundwater thirst of Sierra Vista and Fort Huachuca, and the increase in traffic through all the border towns and along the northernmost highway in Sonora will change this region.
We can debate about which of our activities are “natural” and which are not, but clearly we are ecological players who cannot be ignored in any natural history investigation. As human impacts grow in this region, some understanding of cause and effect may help us make intelligent and responsible decisions. Learning how the place works is the first step to having some power of choice. Our descendants are unlikely to forgive us for intentional ignorance in this time of expanding knowledge and efficient communication.
Any “history” involves condensation and selective interpretation. There are a few obvious limitations to my own interpretations. One is that I live in Arizona, speak English (and stumble through Spanish), read literature generated primarily by natural scientists. The international border is a filter of sorts, allowing only a certain amount of exchange of movement and information. For a long time, the borderlands were on the frontier of both countries, far from the cities and universities that generated or funded scientific inquiries. There are a few notable exceptions, and that generalization is weakening as more agencies and individuals are shifting attention to the region. This is a positive trend, an essential one, for resource exploitation and settlement (including subdivisions and ranchettes in some places) are proceeding even as the scientific probing becomes more focused.
At present, the southern half of the Sky Islands is but little studied, though surely there are people who know the flow of its canyons and some of the secrets of its high trails through islands of dark conifers. There is a lot of wild land out there, particularly south of the border, but few scientists spend much time in the rougher parts of even the relatively accessible Chiricahuas or Galiuros or Santa Teresas. To a large extent, accumulated knowledge correlates well with ease of access.
Local people through their own experiences may be aware of just where El Tigre, the Jaguar, prowls or where the northernmost Boa Constrictor lives or where hundreds of bats issue from underground chambers in a place where no scientist has set foot. The wisdom and experience of indigenous people are beginning to be tapped, but our ignorance of what they know is still vast. Often the sightings of local people (whether an editario living close to the land, a rancher, or a temporary visitor from Nogales or Tucson or Willcox) might be dismissed; something doesn’t really exist until it can be documented by a bonafide scientist. How much are we missing through this attitude?
Could the Mexican Wolf still roam in the Sierra los Embudos or on the mountain called El Tigre, wrapped in the curve of the Rio Bavispe? Maybe. Skepticism is better than unquestioning acceptance of anything (the onza and the chupacabra are real in the minds of many people living in the borderlands, but so far they have defied scientific documentation). Still, we need to be open to reasonable possibilities. Rare organisms can be incredibly difficult to find, particularly if they are actively secretive. Recent documentation of a living Ocelots in Arizona is good proof of that, but I am not holding my breath on the existence of the chupacabra.
Other organisms may be taxonomically secretive; we don’t know yet that they represent something new. Others fairly shout for intensive research once we have declared them “important” through Endangered Species status. Money follows official recognition the way a kangaroo rat runs down its tunnel.
We tend to be woefully ignorant about many things. For example, what’s going on in the soil beneath a ten-foot snowpack on Mt. Graham? How does a tiny hummingbird navigate from the tropics to Madera Canyon, then over to Ramsey? We know little about the diversity of nematodes and bacteria and other minute organisms that run the soil ecosystems. We can scarcely imagine how the world is interpreted by a terrapin, a tarantula, a topminnow, or a trogon. But at least we can ask questions, can seek some answers, and more importantly, we can have the heart to know that most of these things matter. Science certainly is not value free, but our shared values will indeed affect how we use our science.
The available literature for the Sky Islands is overwhelmingly biased in favor of certain well-studied areas (e.g., the San Pedro River, the Huachucas and Chiricahuas, some reserves of The Nature Conservancy or National Audubon Society), some organisms (e.g., the Mt. Graham Red Squirrel, Mexican Spotted Owl, Southwestern Willow Flycatcher, Sonoran Topminnow), or broader topics (e.g., riparian ecology, fire ecology, livestock grazing). How often in my research have I been frustrated by a paper showing detailed mapping of species or communities up to but not south of the U.S.-Mexican border? Even paleontological reconstructions tend to stop at the border; I’m told that the requisite packrat middens or wetlands with preserved cores yielding pollen information just aren’t there in Sonora.
Perhaps my periodic attempts to pull together some of what’s known about this entire region, as incomplete as it must now be, will stimulate others to overcome border blockage and put things into a more complete picture. Perhaps the examples I use will help identify gaps in knowledge that can be remedied.
One well-known environmental educator has written, “You can’t love an ecosystem.” I take issue with that perception, for I know many who are absolutely in love with pine forests or grasslands or mountain meadows or even caves. But I do grant that most people find it easier to empathize with another vertebrate—a large cat or canid or eagle or owl. For that reason, I am going to tell some of my stories through some of the vertebrates who live in these borderlands. I will also briefly mention other critters (even some of the spineless ones) whose stories are relevant, and through organism-centered accounts, I will describe the ecosystems that support them, the changes in the landscapes that have affected them, and some of the actions people are taking on behalf of them.
Today there is a small army of dedicated people working on conservation issues on both sides of the U.S./Mexico border. Perhaps “army” implies too high a level of organization to this movement, but they are dedicated to the causes that they embrace. At the same time, many individuals who are not scientists or activists, who live on the land or who visit these landscapes for various reasons, are making decisions that cumulatively steer the ship of history in particular directions. It is for both these groups, anyone who cares about this homeland, that this collection of stories is aimed.
All of these people are important. The idea of heroes and villains in the on-going saga of the borderlands is perhaps a bit misplaced, for our perspectives change over time. Hindsight makes us question the beliefs of prior generations. The long battles against the Apaches, for example, were readily justified by men determined to “settle” and “tame” the Wild West. The sacrifices and hard work of those who saw the land as a rich source of valuable commodities—beaver pelts, mineral ores, timber supplies, grasses ideal for grazing herds—quickly changed the very landscapes that had drawn them here. The pioneers were heroes in their day, yet in retrospect, they were essentially ignorant of the concept of “sustainability” that many espouse today. Should we treat them then as heroes or villains? The question is inadequate, the concept far too simplistic.
I take a certain measure of pride in being a naturalist, someone attuned to the workings of nature and eager to share what I know (again with humble recognition that my knowledge is limited by culture, training, and inherent intellectual deficiencies). Even scale limits me: the microscopic and intergalactic scales overwhelm me. The whole story is beyond my capacity, just as is my ability to conceive of a universe filled with countless galaxies, infinitely large and timeless (though the “big bang” implies at least a starting point). Most of the story along the border is, for me, dark matter.
But the reassuring thing is that I am not alone in this. There are points of light amidst this dark matter, and those are the interesting things anyway. I hope to string together a necklace of these tiny illuminations to draw attention to the graceful neck of the borderlands. Or perhaps it’s better to think of these stories as little solar lamps lining a path that can take each of us a bit farther into the heart of our continent. Perhaps the enlightened traveler, emboldened by each successful traverse, can extend the pathways, casting light further into the mysteries of life in the borderlands.
Rinne, John N. and W. L. Minckley. 1991. Native fishes of arid lands: a dwindling resource of the desert Southwest. Gen Tech. Rep. RM-206. Ft. Collins (CO): U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station.