A Spring hail storm at the ranch (photo by Zac Tuthill)

An Introduction—Some History Leading to Our Efforts at Restoration, Research, and Education

The Wind River Ranch Foundation is a 501c3 organization dedicated to preserving the Southwestern ecological heritage. The ranch contains 4,500 acres in south-central Mora County, and it is at 6,700 to 7,000 feet of altitude. The canyon along the Mora River is up to 300 feet deep. Major habitat-types on the ranch are western Great Plains short-grass prairie, piñon-juniper (Pinus edulis / Juniperus spp.) and oak (Quercus ssp.) woodland, ponderosa pine (Pinus ponderosa), and a five-mile long riparian corridor of the Mora River. Six side canyons feeding the river contain permanent seeps, springs, and ponds, and some ephemeral water holes. Riparian areas represent less than 1% of the total area in the Southwest, but 75 to 80% of vertebrate life depend on these areas for food, water, cover, and movement (Bogan et al. 1998).

The need for ecological restoration in the region is urgent (see Bogan et al. 1998; NM DG&F 2006). Heavy livestock grazing and fire suppression have changed the flora and fauna of the Southwestern grasslands. Native grasses have declined while less palatable shrubs and weeds have increased. Exotic species thrive in disturbed areas. Piñon / juniper woodlands have advanced onto the grasslands. Following the boom in cattle production during the 1880s, arroyos began forming in the late 1890s. Subsequent erosion degraded the soil’s ability to hold water. The water table lowered, soils hardened, and run-off increased, dumping sediment into the river (Bogan et al. 1998; Allen 2003). In addition, keystone species were eliminated or greatly reduced in number (NM DG&F 2006). When they decline, it causes a series of indirect effects that ripple across trophic levels, affecting life-forms that seem distantly removed from the keystone (see Soulé et al. 2005). All of the above impacts reduce the health of the land.

The degradation of nature can also threaten human livelihoods, particularly in the long-term. Mora County is rural and poor. About 50% of the children in Mora County live below the poverty level. San Miguel County has one the highest per capita Driving While Intoxicated (DWI) levels in the United States. Las Vegas NM has one of the highest per capita rates for violent crime in the state. We hope to nurture a sense of place through the restoration of landscapes and increase ecological awareness toward responsible land-use, including connectivity among landscapes.

Erosion, lack of water, and declining health of grasslands are issues of concern in our region, and 80% of New Mexicans agree that restoration of such ecosystems is important (NM DG&F 2006). Riparian and grassland habitats are both marked as a priority by the Comprehensive Wildlife Conservation Strategy for New Mexico (NM DG&F 2006).

There is no time to waste. One of the recent developments of science is recognition of how non-linear responses and thresholds affect habitat degradation and wildlife management. Nature does not exist in a steady state, but continuously varies within certain bounds, and the species and systems have adapted over time to the range of variability in their particular region. When the range of variation is pushed beyond the threshold of adaptive boundaries, a system can decline at an exponentially increasing rate. Once thresholds are crossed, synergistic effects make it increasingly difficult to restore a system. In other words, thinking of restoration as simply climbing back up the linear stages of ecological succession will not work after thresholds have been crossed. In some cases, we may be considering ecological restoration over geological time scales.

The dominant land-use in our area is livestock grazing on private lands. Thompson (2006-2007: 10) stated “In spite of the evolutionary history of grazing [on the Great Plains], domestic livestock have had a negative impact upon the short-grass prairie.” Thompson’s statement is germane to the restoration of the western Great Plains short-grass prairie. Why did a system that evolved with large grazers decline so sharply under grazing by domestic livestock? After all, it has been reported that there is a 72% dietary overlap between bison and cattle and a 40% overlap between cattle and elk (Wydeven and Dahlgren 1985, Uresk 1986, Holechek et al. 2004). In other words, cattle can substitute for about ¾ of the bison diet. No ecological substitute can completely replace the original, but ¾ is fairly close. Why did the level of decline far exceed the ¼ difference when cattle replaced bison, particularly when the Great Plains evolved with grazing as a major ecological process? We propose that there are several reasons for the decline. They largely relate to human behavior.

One is that even though the Great Plains evolved with grazing, that disturbance historically came from interactions among a number of different grazing species, not just one. The different species had different plant preferences and different grazing styles. They included bison, elk (Cervus elaphus), pronghorn (Antilocapra Americana), deer (Odocoilus spp.), prairie dogs (Cynomys spp.), ground squirrels (Spermophilus spp.), lagomorphs, and untold numbers of invertebrates, like grasshoppers. There is even evidence suggesting a positive feedback between cattle and prairie dogs in the southwestern desert grasslands of the Gray Ranch (Curtain 2006), largely because they keep tall, thick grasses in an early, more succulent stage.  Derner et. al. (2006) found that when prairie dogs occupied 20% of a pasture in Colorado, they reduced the income of that pasture by 88 cents an acre (poison for prairie dogs can cost $4 to $10 an acre without costs of labor).  Female bison gain weight faster when grazing with prairie dogs on mid-grass prairies (Detling 2006).

Over the last 100 years, there has been a concerted campaign to reduce the diversity of grazers to simply one species, domestic cattle (Truett et al. 2001). That broke the interactive link among grazers (whether mutualistic or simply opportunistic). While grazing was a historical disturbance, the present method of excluding other grazing species, and concentration on just one species, does not mimic the original ecological process—despite the close overlap in diet between domestic cattle and bison.

Modern range research shows that cattle graze preferred species of plants first (Briske and Stuth 1982; O’Reagan and Grau 1995; Ambos et al. 2000), and the preferred species were always chosen regardless of grazing strategy (Hart et al. 1993). The damage to preferred species by high livestock density outweighed any benefit that came after cattle were forced to turn to the less-preferred species (O’Reagan and Grau 1995; see a review by Holochek et al. 2000). In the role of grazing as an important ecological process, the preferences of bison may have been mitigated by the preferences of other grazers, with whom they interacted.

Second, fire suppression broke another interactive link between grazers and a key natural process. Both Pfeiffer and Hartnett (1995) and Brown and Stuth (1993) provided evidence that grazing management does not replace the ecological function of fire. When cows favor a particular plant species, it decreases while less palatable competitors increase, but fire can restore the balance (Pfeiffer and Hartnett 1995). For an opposing opinion see Savory (1988).  Similarly, fire without grazing tends to reduce the diversity of plants (Truitt et al. 2001).

Third, cattle have a dietary preference similar to bison, but confinement produces a landscape with less diversity than one grazed by wandering ungulates (Benedict et al. 1996). Indeed, any grazer, whether native or exotic, that is confined and overstocked will over-graze. Bison wandered over an immense region, and during drought they essentially destocked themselves to look for better conditions (Lott 2002).

Confinement also affects soils. Native grazers, including bison, enhanced early successional forbs and some cool season grasses by the action of their hooves (Knapp et al. 1999; Truitt et al. 2001).  This level of disturbance, however, conformed to the “intermediate disturbance hypothesis,” where too little or too much disturbance has a negative effect but the mid-level has benefits (Truitt et al. 2001).  Cattle in confinement tend toward too much disturbance, even when they are regularly rotated through paddocks.  Studies at different locations were consistent. Hoof action from a large number of cattle even for a short period of time reduced soil moisture, reduced the ability of the soil to absorb water, and increased soil erosion (McCalla et al. 1984; Thurow et al. 1986; Weltz and Wood 1986; Warren et al. 1986; Pluhar et al. 1987; Dormaar et al. 1989). 

Fourth, old-style forms of livestock management such as killing predators and competitors, fencing, road-building, introducing exotic plants as forage, using chemicals, altering fire regimes, and grazing in riparian areas took an ecological toll (Freilich et al. 2003). Keystone species have been eliminated from large areas of their former range because they compete with cattle for grass (prairie dogs), impede attempts at irrigation (beavers, Castor Canadensis), or because they are predators who can view cattle as prey (wolves, Canis lupus). Keystones are highly interactive species that contribute greatly to ecological and evolutionary functions. Even though individuals of those species still persist at various locations across their historic range, they are no longer abundant enough or distributed widely enough to exert their ecological function (Soulé et al. 2005). That causes a series of indirect effects that ripple through trophic levels, affecting life-forms that seem distantly removed from the keystone (Terborgh et al. 1999; Miller et al. 2001; Soulé et al. 2005).

Thus, even though domestic cattle and bison have similar diets, the replacement of bison by cattle has produced ecological damage because cattle are managed differently than bison behaved naturally.  Cattle grazing usually aims for uniform cropping of plants instead of the habitat patchiness that is necessary for species diversity (Truitt et al. 2001).  Furthermore, livestock are produced for human food.  Because our species is rapidly increasing in numbers, this means livestock managers will benefit by increasing the efficiency of production (Truitt et al. 2001).  So, the diversity of natural grazers has been reduced or eliminated, and predators are killed.  As a result, changed ecological processes have caused declines in species diversity. We recognize that visionary ranchers have changed their livestock grazing to step more lightly on the land. Nevertheless, we still bear the burden of historical practices. We also bear the burden of those who still embrace old-style management today. Several groups are working to change the latter (like the Quivira Coalition and the Malpai Borderlands Group), and we hope to help with such changes.

Given the evolutionary history of grazing on the Great Plains, species diversity and landscape matrices can be restored, at least at smaller scales. We propose that if cattle are to be viewed as an ecological substitute for bison on the Great Plains, then cattle should be managed to mimic the original behavior of bison and with the same ecological interactions (e.g. no prairie dog poisoning). Because livestock are here to produce food for a growing human population, and for economic benefits to the manager, that is unlikely to happen–particularly over the large scales necessary to revive grassland health.   In addition, cattle and bison differ in evolution, morphology/physiology, and behavior, and we propose those differences make bison more suited to the Southwest than cattle.  For a more detailed explanation of those differences, see the page on this website titled Restoration, Section 5. b. Bison.

There are ways, however, to reduce the negative impacts we discussed above.  While there are a number of proposals for managing livestock, there is no universally-applicable magic bullet. To be a responsible producer requires a lot of effort and close attention, regardless of the method. The Southwest is often in some form of drought. During drought, numerous experiments have shown that conservative stocking levels are the best way to maintain plant productivity and range health (see reviews by Holochek et al. 2000; 2004).  But, a slim margin of profit in agriculture, combined with the American desire for a high standard of living, places economic pressure against following that advice.  No grazing system will work well for the land or producer when there is a severe drought.  At the Wind River Ranch, we share a herd of bison with the Jicarilla Apache Cultural Affairs Office.  We are investigating the ecological affects of bison on grassland health and grazing interactions.  We are doing this in conjunction with the Inter-Tribal Bison Cooperative.

In a brief summary, all habitat types have declined because humans have tried to dominate nature. In the grasslands, the ecosystem was simplified, competitors and predators were eliminated, processes were changed, and interactions were broken. The grasslands evolved with grazing (in some places quite heavily), but not the style humans have introduced. Uniform utilization of grasses is counter to conservation of biodiversity, which requires patchy grazing, species interactions, and a landscape matrix of habitat types (Truett et al. 2001). The human mind-set of domination and profit, combined with human numbers, patterns of consumption, global markets, and the economic discount rate, thus works against sustainable use of the prairie, just as it does for any other industry or profession. There is, however, a long-term cost. We are all guilty at some level or another.  To live within nature instead of on top of it will change the landscape from what you see today. But before we can attempt that, we must change the way we think and the values we hold.

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