Habitat Guideline for Mule Deer
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- Bu səhifədəki naviqasiya:
- Kothmam
- Sampson
- Wood and Blackburn
- Misstatements and contradictions
- I would like to know if, and how, you plan to correct the record. II. Explaining Holistic Planned Grazing
- Correct grazing planning makes overstocking, over-grazing, and over-resting impossible. Plants need animals as much as animals need plants
- : individual plants are harmed, and eventually will die, from (1) too much herbivory (“over-grazing”) but also, from (2) too little herbivory (“partial and/or total rest”).
- Over-rest: the new insight
- Sins of commission sins of omission
- This cannot be shown to hurt plants (
McCalla also found that “the results of these studies indicate that infiltration rates of pastures grazing under a deferred rotation system (4-3: 12:4 months) were similar to those of livestock exclosures and greater than high-intensity low frequency pastures (McCalla et al. 1984). This is an excellent point: of several poor systems tested, relatively intensive animal stocking with longer recovery periods works better, as planned graziers predict. McCalla did not test planned grazing. Kothmam, on whom McCalla relies concludes that “management systems which utilize intermittent grazing and deferment, but depend upon the operators’ judgment and not a pre-determined schedule … can be very effective in improving or maintaining range condition … but do not lend itself (sic) to any system of nomenclature other than grazing management. (Kothmam 1974).” This is consistent with the findings of planned grazing. Sampson on whom Kothmam relies found, that, “on bunch grass ranges, deferment of grazing every three years or so is highly beneficial to the vegetation. … Some form of rotation grazing is essential. Natural re-vegetation is generally unsuccessful where there is spotty over-grazing of the more accessible portions and too-light cropping of the steeper slopes. Any system of rotation … should provide for shifting the animals so that no given portion of the range will be grazed at the same time every year (Sampson 1951).” Each comment reflects precepts of planned grazing, although this was not a test of planned grazing. Thurow et al. “Primary infiltration was related to the total organic cover of the plant community. The amount of cover was more important than the type of cover. Short-duration grazing and heavy continuous grazing reduced the plant cover and therefore harmed infiltration. Infiltration rates were greatest at the first five minute reading for each vegetation type and then declined in subsequent reading until a terminal infiltration rate was reduced.” (Thurow et al. 1986). In other words, the initial wetting of dry soil is critical. That is why hoof action is beneficial to initial water absorption. Whereas, plant condition: foliation, root mass, insect activity and liter are critical to deep infiltration (Heffelfinger et al. 2006; Savory et al. 1999; Butterfield et al. 2006; Gill 2007; Sampson 1951; Holechek et al. 2000; Pluhar 1987). None of this study contradicts conclusions that planned graziers arrived at decades ago. The study did not test planned grazing. Weltz studied the difference between heavy continuous, moderate continuous, complete deferment, and SDG and found that short-duration grazing had no beneficial effect on two different sites (Weltz 1986). Not a test of planned grazing. Wood and Blackburn are cited by Weltz as finding that the Merrill 4 pasture -3 herd system approached the optimum infiltration rate of a 20-year old exclosure (Wood and Blackburn 1981, Weltz 1986). In other words a system that incorporated relatively intense grazing with longer recovery period was the best tested grazing system. Weltz also stated that the SDG pasture had the least amount of grass of any of the grazing treatments. But in the Fort Sumner study where the short-duration pasture was rested the infiltration was greater than the other grazing treatments although no better than the exclosure. (Weltz 1986.) This study concluded that where practices that increased the health of the plant community were followed, the water infiltration was highest (Weltz 1986). Planned graziers would say none of these systems are ideal but their relative merits align with the degrees of over-grazing, over-rest, and, adequate recovery periods inherent in each. Warren et al. studied a site devoid of vegetation, following periodic trampling of intensive grazing systems. They found that the deleterious impact of livestock trampling generally increased as stocking rate increased. Damage was augmented when the soil was moist at time of trampling. Thirty days of rest was insufficient to allow hydrological recovery. This study consisted strictly of bare soil inquiries. The trampling of the bare soil involved large animal numbers five times at 30-day intervals through the growing season with the soil wet before the trampling. (Warren et al. 1986). Planned graziers would not return large herds to bare soil five times during the same growing season, nor in the desert could heavy rains be expected to coincide with such animal presence. This does not test planned grazing. What was found is consistent with what planned grazing principles and common sense would predict. Pluhar conducted experiments in different scenarios and found that what helps plants helps infiltration. Infiltration rates were least in the spring, and most in the fall, because in the spring soil was dry and plant cover minimal compared to conditions at the end of the growing season (Pluhar et al. 1987). This is what planned graziers would expect: whatever system is tested that tends to bring animal numbers up for the shortest time possible to achieve the desired amount of grazing will be the one that works best. Not a test of planned grazing. Misstatements and contradictions #1 “Studies from desert rangelands showed no advantage to various rotational grazing systems over continuous grazing in range condition per Holechek in 1994 (page 15, Heffelfinger et al. 2006).” This summary statement is wrong: here is what Holechek said. “Best pasture rotation grazing at 25% higher stocking rate than moderate continuous grazing … improved range condition and increased forage on the pasture where it was applied compared to moderate and heavy continuous grazing (Hoelchek et al. 1994). “Ranchers should be encouraged to avoid heavy use year after year (sic) on the same key areas. That is where rotation grazing … can be useful (Holechek et al. 2000, page 14).” I read the Holechek studies and his sources. Holechek contradicts your summary at least twice. At least eight other studies on which he, and you rely also contradict your representation (Manley et al. 1997; Anderson et al. 1988; Taylor et al 1993; Kothmann 1974; Sampson 1951; Wood and Blackburn 1981; Weltz 1986; Pluhar 1987). #2 Statement #1, at page 15 is contradicted twice on page 15 and again on page 19: “Timing and intensity of grazing are important considerations …” “Timing can be important for fawn cover …” “Grazing southwestern rangelands in winter has been shown to have less impact on forage production and range condition than grazing during the growing season …” (Heffelfinger et al. 2006). These statements are correct: rotation in some form is helpful. What shall we call grazing adjustments for timing, intensity and growing season deferral other than forms of rotation? Seasonal considerations are always part of the planned grazing process. Protocols which allow some plant recovery will always work better than continuous grazing at any density. #3 “Studies from desert rangelands showed no advantage to various rotation grazing systems over continuous grazing in … financial returns (per a study by) Holechek (in) 1994” (and) 2000.” (Heffelfinger et al. 2006). Negative comments by Holechek in 2000 were in regard to SDG’s only (Holechek et al. 2000). Here is the rest of what Holechek said: “This strategy (best pasture rotational) appears quite sound for ranchers with a 10-30 year investment time frame.” “Best pasture rotational grazing at a 25% higher stocking rate than moderate continuous grazing, was unsound over a short-term (10 year) basis … (but) … financially effective for ranchers with a long-term (10-30 years) investment time frames (Holechek et al. 1994).” Other studies relied on by yourselves also contradict this conclusion (Manley et al. 1997; Taylor et al. 1993). Tripling forage under planned grazing is like getting two free ranches (Savory et al. 1999; Butterfield et al. 2006; Gill 2007). How are we to restore plants and animals except over the long-term? Not only do Holechek’s complete statements contradict your summary, but, in making those he considered only grazing economics. Holechek omitted the value of wildlife, hunting, and land appreciation associated with habitat improvement, which together total many times that of gains in grazing profits (Gill 2007). #4 “Despite this (disproved theory) some range managers continue to allow or even promote inappropriately high stocking rates with a short duration grazing system as proposed by Savory (in 1983) (Heffelfinger et al. 2006).” In other words, planned graziers advocate SDG’s or other grazing methodologies that overstock and do not plan moves or allow plants to fully recover between grazings. That is wrong per se. I know this because, as graduates of HMI’s Ranch and Rangeland Management School, I and other family members understand and practice planned grazing protocols continuously (Gill 2007). Moreover, no one has advocated more persistently, educated more effectively, or persuaded more people in favor of integrated grazing, financial, land and personal ranch planning, and monitoring than Allan Savory and Holistic Management International (HMI) (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). You advocate grazing planning: (Heffelfinger et al. 2006, pp. 16-19). I agree with that advice. Of the several planning methodologies I have seen, all borrow heavily from planned grazing in nomenclature, format, or otherwise. Future editions should refer readers to Holistic Management International at www.holisticmanagement.com and the Quivira Coalition at www.quiviracoalition.org as sources from which to learn grazing, financial, and land planning, and monitoring. Correcting the record Obviously the conclusions on planned grazing are wrong, as this analysis shows. If a scientific theory disproving planned grazing exists, it was not presented in these studies. The public has a right to expect its employees and the quasi-public entities which it supports, and on whom it relies, to use the best science available. For years to come these conclusions will be offered as “proof” that planned grazing does not work. This is a great disservice to the public and to our shared goals for mule deer. I would like to know if, and how, you plan to correct the record. II. Explaining Holistic Planned Grazing Holistic Planned Grazing is all about getting animals to the right place at the right time for the right reason. The right reason is to use animals to improve desert grassland ecology by concentrating cattle herds, rather than dispersing these as is the norm in conventional desert range management. This intense grazing must always be followed by long-enough periods without grazing to allow complete plant recovery. This high-concentration-long-recovery is better for plants since it mimics the natural behavior of large herds of wild herbivores in the presence of their predators (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). These herds are known to have existed in our deserts until humans arrived about 10,000 years ago (Heffelfinger et al. 2006; Martin et al. 1984; Martin 2005). Whereas conventional practice focuses on over-grazing alone, planned grazing focuses on over-grazing, over-rest, and recovery. Conventional range practice is obsessed with overuse resulting from too many animals (Heffelfinger et al. 2006). This leads conventional range science to focus on animal numbers. It generally assumes year-round stocking. That assumption is so imbedded that its calculations normally rely on only two variables: area and animal numbers. Your stocking recommendations, found at page 16B #1 - #4 reflect this two-dimensional mindset (Heffelfinger et al. 2006). Planned grazing always thinks in terms of three variables: area, animal numbers, and days. This three-variable thinking follows from the observation that in undisturbed wild states, whether the Great Plains of North America or the savannas of East Africa, wild bison or wildebeest, among many other species, were seen in large numbers for short times and were constantly moving. They were not found in small numbers and present year-round (Savory 1983; Savory et al.1999; Butterfield et al. 2006; Martin et al. 1984; Martin 2005). Conventional, two-variable thinking as you demonstrate it addresses overuse by reducing set-stocked animal numbers (Heffelfinger 2006). This creates fatal over-grazing, and fatal over-rest (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). That is why conventional desert grazing protocols generally fail, and are viewed with ambivalence by conventional range scientists, many of whom think the best of them are lesser evils (Gill 2007). Planned grazing avoids overuse by use of the largest herd possible for the shortest time necessary to accomplish the planned harvest (Savory 1983; Savory et al. 2006; Butterfield et al. 2006). For example: #25 head for 365 days = about 9000 AD's. 1000 head for 9 days = 9000 AD's. This is the identical grazing pressure as measured by forage consumed, but the former produces both over-grazing and over-rest, since under light stocking over long periods, favorite plants are repeatedly re-bitten while other plants become inedible (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). The erroneous conclusion that planned grazing means an increase in herbivory and consequent overuse due to doubling or tripling stocking rates wrongly assumes stocking rates and protocols as conventionally defined (Heffelfinger et al. 2006; Holechek et al. 2000). This mistaken perception reveals a failure to understand what planned grazing is (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). Over time, planned grazing causes plant communities to become more productive and this has been proven to increase forage and therefore AD's (Savory 1983; Savory et al. 1999; Butterfield et al. 2006; Gill 2007). This increased productivity is the basis for increased herbivory: planned grazing starts with a grazing plan based on monitoring plant conditions, plant growth and available forage. Planning is the sine qua non of planned grazing. (Savory 1983; Savory et al. 1999; Butterfield et al. 2006; Gill 2007). Planned grazing planning methodology adjusts stocking rates up or down, and arrives at animal moves by a formal protocol, that corrects the wandering intuition that is part of conventional range science’s acceptance of broad-brush stocking guidelines (i.e. 125 acres per animal unit). Correct grazing planning makes overstocking, over-grazing, and over-resting impossible.
developed as these communities of living organisms co-evolved over at least 20 million years (Savory 1983; Martin et al. 1984; Martin 2005). In this view, cattle and other exotic-domesticated species are proxies for extinct wild species which were symbiotic with each other and plants (Martin et al. 1984; Martin 2005). Holistic practices rest on two key insights with respect to desert grasslands: individual plants are harmed, and eventually will die, from (#1) too much herbivory (“over-grazing”) but also, from (#2) too little herbivory (“partial and/or total rest”). Over-grazing defined Insight #1 concerns over-grazing which you define as: "...a condition where the range is chronically overused for a multi-year period resulting in degeneration in plant species and plant composition and soil quality "(Heffelfinger et al. 2006 p.11; Severson and Urness 1994:240). Planned grazing practitioners consider this definition deficient. We define over-grazing as follows: "When a plant bitten severely in the growing season gets bitten severely again while using energy it has taken from its crown, stem bases, or roots to re-establish leaf. Generally, this results in the eventual death of the plant. In intermediate stages it results in reduced production from the plant. Over-grazing occurs at three different times: (1) When the plant is exposed to the animals for too many days and they are around to re-graze it as it tries re-grow; (2) when animals move away but return too soon and graze the plant while it is still using stored energy to reform leaf; or (3) immediately following dormancy when the plant is growing new leaf from stored energy (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). These definitions are very different. Only one recognizes over-grazing as the plant-by-plant, as opposed to area-wide, phenomenon which thoughtful observation shows it to be. Only one focuses on the correct relation of timing and damage. As the SDG studies prove, overgrazing can happen in a few days: it doesn’t take years. Planned grazing principles originate in large part from the understanding of over-rest, and incorporate consideration of timing, seasonality, long recovery periods and holistic thinking in general (pp. 19-20). The different definitions reflect competing concepts of range science as revealed in a comparison of paradigms (pp. 18-22). Scientific history demonstrates the difficulty of comparing definitions across paradigms. For example, even though both Newtonian and relativistic dynamics use the term mass, they don’t mean the same thing by that term. For Newton, mass is a property. For Eisenstein, mass is a relation: e = mc2 (Kuhn, p. 128, 149, 29-30). We cannot reconcile these definitions. One must choose between paradigms (Preston pp. 88-94; Kuhn p. 103, 112, 148). “Practicing as they do in different worlds, the two groups of scientists see different things when they look from the same point in the same direction (Kuhn p. 148).” Over-rest: the new insight Insight #2 is the most important addition to modern desert range science, the least understood, and the most resisted by conventional practitioners. This misunderstanding arises largely because total and partial rest is very beneficial to damaged plant communities in moist environments. Conventional desert range practice flows from the erroneous though understandable assumption that what works in moist climates will also work in deserts (Savory 1983; Savory et al. 1999; Butterfield et al. 2006; Taylor et al. 1993). The error is compounded by the traditional view of cattle and domestic animal herbivory as parasitic to plants. Both assumptions are wrong. As you correctly state: "Decades of experience, and more recently research, has shown that general rules and range management practices in more mesic ranges (i.e., ranges having a greater, balanced amount of moisture) cannot be applied successfully to Southwestern (desert) rangelands (Heffelfinger et al. 2006).” Over-rest defined At best, conventional range science only dimly perceives this phenomenon. Conventional practitioners focus on avoiding damage from over-grazing which they perceive as happening across large areas instead of plant-by-plant (Heffelfinger et al. 2006). Yet, on lightly-stocked desert ranges and exclosures, anyone can observe dying plants that have not been grazed for years (Savory 1983; Savory et al. 1999; Butterfield et al. 2006; Gill 2007). Planned grazing practitioners define an over-rested plant as: "A bunched perennial grass plant that has been rested so long that accumulating dead material prevents light from reaching growth points at the plant's base, hampering new growth and eventually killing the plant. Over-rest occurs mainly in the more brittle environments where, in the absence of large herbivores, most old material breaks down through oxidation and weathering rather than decay" (Savory 1983; Savory et al. 1999; Butterfield et al. 2006, photo p. 16). Sins of commission sins of omission Desert plants can be harmed by inactions as well as actions. De-stocking will not reverse desertification: if it could, all we would need to do to reverse desertification is remove domestic and wild animals. Decades of experience with de-stocking, and with experimental exclosures, prove this fails (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). Consider the adverse effects of destocking at Big Bend Park (Gill 2007). Indeed, there is virtual agreement that de-stocking does not restore damaged grasslands or reverse desertification: "Long-term deferments from grazing in arid and semiarid regions may not result in any significant improvement in range condition (Heffelfinger et al. 2006; Laycock 1991 p. 429, 1994; Savory 1983; Savory et al. 1999; Butterfield et al. 2006; Holecheck et al. 1998)."Improvements MAY TAKE (emphasis added) 40-50 years (Heffelfinger et al. 2006; Valone et al. 2002; Guo 2004). Not one of your studies finds, or predicts, that de-stocking WILL reverse desertification. Why is this so? Because plants need animal impact and sicken without it. Restated technically: total and partial rest invariably harm plants in desert environments (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). "Grazing is neither good nor bad" (Heffelfinger et al. 2006 p.11) is an erroneous conclusion, if by 'good' and 'bad' you mean 'beneficial' or 'damaging' to habitat. Correct grazing and animal impact is necessary for plant community health: these must come in a form that avoids BOTH over-rest and over-grazing, either of which will kill desert plants (Savory 1983; Savory et al. 1999; Butterfield et al. 2006; Gill 2007, photo p. 16). Occham’s Razor There is a scientific principal which says: “All things being equal, the simplest explanation is the most likely.” The theory governing planned grazing is simple, and scientifically elegant. It organizes all observed phenomena in a way that explains most observed events (such as the findings of your studies) and accurately predicts the outcomes of contemplated acts. I have not disagreed with your primary or incorporated studies except to the extent any is misrepresented as a test of planned grazing. The observations themselves appear sound. Planned grazing predicts that avoidance of over-grazing through short grazing periods by large animal numbers, along with long recoveries, and avoidance of spring grazing, will avoid over-rest and over-grazing. Reconsider the observations and recommendations of your studies in the context of these organizing insights. As presented, these are a confusing jumble of seemingly unconnected, often contradictory recommendations and practices. Tested against these criteria they make sense. They coalesce into a coherent and predicable pattern. They are now part of a simple, easily-learned theory by which we can manage desert rangelands.
to fully recover, or over-grazing will result (Savory 1983; Savory et al. 1999; Butterfield et al. 2006; Gill 2007, photo p. 16).
should be taken by large-enough herds to avoid over-rest. Grazing is followed by recovery periods that allow for complete plant recovery. This cannot be shown to hurt plants (Savory 1983; Savory et al. 1999; Butterfield et al. 2006). Yüklə 105,47 Kb. Dostları ilə paylaş:
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