3.1 ECOLOGICAL "COSTS" OF LIVESTOCK WATER DEVELOPMENTS
|While surface waters may have served the needs of area
wildlife over time, the same surface waters may not be sufficient to meet the
needs of large domestic animals or of concentrated groups of domestic animals.
In other instances, such as in the case of water developments for wildlife-
the human intervention may be intended to increase wildlife numbers for hunter
harvest beyond an existing habitat capacity. In some instances, wildlife water
developments have been carried out in order to introduce or re-introduce
threatened species or exotic species into habitats not naturally (or no longer
naturally) capable of supporting desired population numbers.
Although some benefits may occur to resident or migratory wildlife species through the construction of particular types of water developments, there is increasing public concern that the overall ecological costs of water developments do not justify their construction and placement within natural habitats. Although Section 3.1 is specifically intended to address the impacts of livestock developments, wildlife water developments may also result in similar adverse impacts. This section is not intended to serve as an all-encompassing treatise- but to give the reader/viewer an introduction to the ecological impacts most commonly associated with livestock water developments.
For review purposes, the ecological "costs" or impacts
associated with water developments created for domestic livestock have
been divided into four subsections. These subsections cover some of the basic
impacts of livestock water developments to natural hydrologic functions, to
soils (including compaction and accelerated erosion), to native plant community
values, and to wildlife habitat values. Specific wildlife access and safety
issues will be addressed more extensively in report Section 4.1.
will also include some discussion on the impact of water developments to
recreational and scenic values as they relate to human enjoyment of natural
wildlife and wildlife habitats.
Impacts to Natural Hydrologic Functions
The movement of water from the earth’s surface to the atmosphere and back again is referred to as the hydrologic cycle. The hydrologic cycle can be broken down into those components found within a particular watershed. Watersheds are an area drained by a particular stream or set of streams and that is divided geographically from adjacent drainages or stream systems. All of the precipitation falling on a watershed is either stored in the soil or is returned to the atmosphere via evaporation (from land or water surfaces) or through vegetative transpiration (Brady and Weil 1999). The overall disposition of water within a particular watershed can be expressed by a water-balance equation that, in its most simplified form, can be expressed as follows:
P = ET + SS + D
where P = precipitation, ET = evapotranspiration, SS = soil storage, and D = discharge (Brady and Weil 1999).
Water developments for livestock and associated grazing impacts can profoundly affect natural hydrologic functions. Water developments typically involve some sort of physical diversion, capture, or storage of natural surface or ground waters, and may disrupt or alter over-surface flows and natural watershed drainage or discharge functions. Water developments are also typically involved with some type (or measurable level) of vegetative or soils alteration - ecosystem components that are inextricably associated with functions of the hydrologic cycle.
Grazing management standards and guidelines have been developed in recognition of the potential for water developments to impact hydrologic functions. A sampling of BLM Standards and Guidelines from a number of western states reveals the following management directives or guidelines regarding protection of natural hydrologic functions:
State lands departments; such as Idaho Department of Lands (IDL) typically adhere to BLM Standards and Guidelines for range management direction. National Forests must each develop their own Forest Plan in order to address livestock grazing and other management needs. A sample of forest plan directives regarding livestock grazing management and related hydrologic functions include the following excerpts from the 1987 Sawtooth Forest Plan:
While a great many "paper" plans may have been developed to govern livestock management on public lands as it relates to hydrologic functioning and associated riparian-wetland and watershed values, this does not necessarily mean that management directives are being carried out at the field level. One of the main sources of public dissatisfaction with agency management is the failure of those agencies to implement management plans at the field level. While agency personnel and livestock permittees may be annoyed by increasing public scrutiny of their actions, it is important to remember that the public has a vested interest in the responsible management of state and federal lands. As livestock grazing is the most widespread human activity occurring on our public lands, it thus receives the lion’s share of public concern and requests for accountability.
Figures 3.1-1 through 3.1-10 provide illustrations of existing water developments on BLM, IDL, and FS lands in Idaho. These photos provide excellent evidence as to whether or not the developments meet one or more of the management guidelines listed above.
As is evidenced by these photographs, land management directives may not actually be implemented at the field level in accordance with the original management intent. Convenience has likely been a factor in the placement of some of these developments- it doesn’t take much in the way of materials or engineering to move water a few feet. Some of these developments were carried out prior to the establishment of current grazing standards and guidelines. However, none of these reasons eliminates or mitigates the ecological costs incurred (and that continue to mount cumulatively) through the placement of these developments within existing riparian-wetlands, or compensates for the loss of overland and other surface flows captured by reservoirs or spring boxes.
Not only have many water developments around the west been inappropriately sited to begin with- there has been little effort undertaken by land managers to alleviate former shortsightedness. A few troughs have been moved and a few token exclosures constructed in response to identified resource concerns; with some site-specific concerns having been identified by the interested public, some by permittees, and some by agency personnel. But by and large these structures remain within the west’s wet meadows, springs and seeps, and adjacent to or within riparian-wetland habitats by the thousands.
Along with dugouts and reservoirs that may permanently
intercept creeks, springs, and various forms of run-off from precipitation
events or snowmelt, these water development sites continue to disrupt or
interrupt natural spring and creek flows and functions. There has been no
uniform accounting west-wide of the ecological costs involved with livestock
water developments in terms of lost or interrupted hydrologic functions, loss
of fisheries values, or in the loss of associated riparian-wetland and other
Impacts to Soils and Accelerated Erosion
Brady and Weil (1999) define erosion as: 1) The wearing away of the land surface by running water, wind, ice, or other geologic agents, including such processes as gravitational creep, and 2) Detachment and movement of soil or rock by water, wind, ice, or gravity. Accelerated erosion is defined by Brady and Weil (1999) as:
Erosion much more rapid than normal, natural geological erosion; primarily as a result of the activities of humans, or, in some cases, of animals.
Vallentine (1974) notes that livestock water developments should be located on well-drained, non-erosive sites. Figures 3.1-11 and 3.1-12 provide a comparison of proper and improper siting strategies.
Bell (1973) notes:
Misplaced or too widely spaced water locations cause undesirable grazing patterns. If animals have too far to travel between water and suitable grazing areas, the pattern of use is that of grazing out and trailing back. As this continues, trails become longer and deeper, making bigger and better water channels to carry rainfall off the range and inducing erosion.
Figures 3.1-13 and 3.1-14 provide a comparison between two livestock developments that represent an expected (generally acceptable) grazing pattern and an unacceptable or improper grazing pattern associated with the development.
Similar to the management directives aimed at ensuring proper hydrologic functions (inclusive of riparian-wetland and watershed functions), management guidelines have been developed for preserving soil values and to provide protection against accelerated (human-induced) erosion. Examples within BLM Standards and Guidelines from Idaho, Utah, and Montana include the following management directives or guidelines regarding soils or soil health:
Figures 3.1-15 through 3.1-22 provide illustrations of existing water developments on BLM, IDL, and FS lands in Idaho These photos provide excellent evidence as to whether or not the developments may be achieving any of the management guidelines listed above.
Figures 3.1-15 through 3.1-22 reflect concerns relating to soil values and accelerated erosion. Despite management directives designed to avoid these kinds of damages; impacts including severe compaction, loss of groundcover over extensive areas, loss of soil crusts across extensive areas, and accelerated erosion are common on Idaho and other western rangelands.
Across a five-year survey period of grazing lands in Idaho, Nevada, and Utah, the author has observed only a few examples of proper siting of troughs. The remaining vast numbers of troughs and other developments observed during the survey period upon which this report is based (1998 to 2003) exhibit moderate to extreme failures of management standards relating to soil and other resource values. In many instances, troughs and other types of water developments and their associated grazing activities are very obviously contributing to accelerated erosion of both upland and riparian-wetland habitats.
Jones (2001) notes:
One of the chief hydrological impacts attributed to grazing in the arid west is increased storm runoff caused by an interaction of two chief factors: 1) greater soil compaction and thus decreased soil infiltration caused by trampling…and 2) less vegetation, litter cryptogamic soils on the surface to absorb rain (Ellison 1960). Evidence of increased storm-runoff on grazed versus ungrazed watersheds is considerable (Lusby 1979, Meehan and Platts 1978, Stevens et al. 1992). Increased storm runoff indirectly triggered through grazing can in turn cause further soil erosion and flooding…There are a number of good reviews on this topic that describe the indisputable impact of livestock grazing on soil compaction, infiltration and runoff (see Gifford and Hawkins 1978, Kuffman and Krueger 1984, Fleischner 1994, Trimble and Mendel 1995, Jones 2000, and Carter 2000).
Grazing can also lead to "gullying" (Winegar 1977) and channel incision (Kavalchik and Elmore 1992), due to a combination of bank instability and downcutting from higher flood energy.
There has been no uniform or systematic accounting of the
ecological costs involved specifically with livestock water developments. There
are few evaluations of lost soil values, lost soil functions (such as
permeability or infiltration), or of accelerated erosion associated directly
with water developments and related range "improvements." Allotment assessments
by public agencies typically gloss over or fail to address the negative impacts
relating directly or indirectly to livestock water developments. Plans and
decisions often promote livestock developments as representing the needed improvement
for impaired rangeland ecosystems. Based upon thousands of field observations
across the west, the limited ecosystem improvements associated with water
developments are often negated by the adverse effects of these very same
developments (along with the often required new pipelines, fencing, roads, etc.).
It appears that impacts are simply being transferred from location to another
in many cases. This scenario is indicative of range overstocking as described
by Vallentine (1974).
Impacts to Native Plant Community Values
A major public concern for any of the activities associated with the grazing of domestic livestock is the potential for serious impact to native plant communities. The very nature of livestock grazing will result in consumption (removal) of native plant materials from native ecosystems, trampling impacts (trailing, bedding), impacts to or destruction of soil crusts, introduction of large amounts of solid animal wastes, and alteration of soils or hydrologic functions vital to plants. Alteration of plant community values may then exert profound influences upon native wildlife species dependent upon vegetation for food resources, prey base resources, hiding cover, nesting cover, escape cover, thermal cover or other needs.
Many if not most modern rangelands have been altered through some type of anthropogenic (human) activity designed to increase forage production (generally grasses) for use by domestic livestock. Influences include but are not limited to exotic seedings, use of fire, and the chaining or spraying of native woody species. Despite these "treatments," most western rangelands still have remnant native plant community values (e.g. sagebrush, native forbs or grasses) that coexisting with exotic or seeded species and are deserving of recognition.
Rangeland management is most often carried out (in theory if not always in practice) in order to maximize natural or seeded production for domestic livestock purposes. Many agency resource plans may also indicate livestock production efforts as being carried out for wildlife- most commonly for big game benefit. Rangeland management standards and guidelines have been developed with the stated goals of preserving native plant community values. This includes values for both riparian-wetland and upland habitats. Examples found within BLM Standards and Guidelines from Idaho, Utah, and Montana include the following directives or guidelines relating to plant community health on public rangelands:
Indicators may include, but are not limited to, the following: 1. Native plant communities (flora and microbiotic crusts) are maintained or improved…2. The diversity of native species is maintained. 3. Plant vigor (total plant production, seed and seedstalk production, cover, etc.) is adequate to enable reproduction and recruitment of plants when favorable climatic events occur. 4. Noxious weed are not increasing. 5. Adequate litter and standing dead plant material are present for site protection and for decomposition to replenish soil nutrients relative to site potential. (Idaho BLM 1997 Standards for Rangeland Health #4)
Water developments pose particular concerns for native plant community values for two major reasons: 1) the developments may concentrate livestock numbers or livestock use in upland areas that might not have otherwise been grazed in any substantial amount; and 2) inappropriate placement of developments within riparian-wetland habitats poses significant risks to a number of resource values, including plant community values.
Figures 3.1-23 through 3.1-46 are illustrative of whether or not grazing guidelines and standards relating to plant community values are being implemented (respective to water developments) at the field level. These representative examples come from a variety of public land locations in southern Idaho.
Livestock grazing in general, as well as grazing associated directly with water developments, results in disturbances of varying levels. The most observable impacts relating to native plant community values are trampling and partial to complete removal of vegetative cover. This can include impacts to common as well as to uncommon or rare plants. Vegetative removal can include extensive areas that may encompass up to several square miles. The effects of the removal or disturbance of vegetation cannot be realistically separated from impacts to soils and hydrologic functions. John Muir (1911) eloquently described this interrelationship: "When we try to pick out anything by itself, we find it hitched to everything in the universe."
Loss of vegetation and the accompanying soil impacts may range from compaction to pulverization of soil structures, to loss of water infiltration properties and active soil erosion. Loss of vegetation results in disruptions of the hydrologic cycle- from loss of the hydraulic properties of root systems or shading of the soils from the sun, to the loss of transpiration and precipitation relationships. Loss or disturbance of riparian-wetland vegetation can lead to accelerated erosion, sedimentation, lowering of water tables, and other undesirable impacts to natural ecosystems.
Depending on the annual levels of disturbance, grazing of native vegetation may exert a profound influence on the presence and reproductive viability of many wildlife species. Years of field observations by many scientists, including the author of this report, reveal that water and trees are rarely the major limiting factor for wildlife. The most observable limiting factor for many if not most wildlife species (from invertebrates to vertebrates) is the presence or lack of understory or groundcover values. Impacts of water developments on wildlife will be discussed in greater detail in the next subsection, Impacts to Wildlife Habitat Values.
Noxious weed introductions are another impact that can be linked directly to water developments- as weed invasions correspond with frequent soil disturbance regimes and repeat visits by weed vectors (e.g. livestock, vehicles). The soil disturbance inherent to pipeline construction can also serve as weed corridors - enhancing the spread of both noxious species and exotics (such as cheat grass).
Belsky and Gelbard (2000) note:
The contribution of livestock grazing to weed invasions has generally been downplayed. While the effects of drought, historic overgrazing, fire, and seed introductions associated with outdoor recreation, roads, and wildlife have been emphasized…At the landscape and regional scales, livestock grazing is one of several factors causing and enhancing the invasion of alien weeds into grassland, shrubland, and woodland communities; but at the community scale, livestock may be the major factor causing these invasions.
Weeds represent plant community changes that may affect native wildlife population densities as well as native wildlife distribution. Many native invertebrates are host-plant specific and are unable to utilize exotic plant species. Weeds and exotic plant communities may actually favor the range expansion of exotic or introduced insects and other non-native wildlife.
Impacts to Wildlife Habitat Values
Water developments represent identifiable, site-specific impacts within native wildlife habitats. They also may contribute substantially to the overall cumulative impacts of domestic livestock grazing within a watershed or other geographic region. While there have been a variety of agency, university, and state wildlife department studies carried out to analyze the impacts of domestic livestock grazing on wildlife habitats in general or in relation to specific species of wildlife (e.g. big-horned sheep, Neotropical songbirds), few if any studies have specifically analyzed the local (or the cumulative local and regional) impacts of livestock water developments on wildlife species or their habitats. The same is true even for those developments specifically constructed for wildlife.
In relation to water developments for wildlife, Rosenstock, Ballard, and deVos (1999) state:
Based upon a comprehensive review of scientific literature, we conclude that wildlife water developments have likely benefited many game and non-game species, but not all water development projects have yielded expected increases in animal distribution and abundance. Hypothesized negative impacts of water developments on wildlife are not supported by data and remain largely speculative. However, our understanding of both positive and negative effects of wildlife water developments is incomplete, because of design limitations of previous research. Long-term experimental studies are needed to address unanswered questions concerning the efficacy and ecological effects of water developments. We also recommend that resource managers apply more rigorous planning criteria to new developments, and expand monitoring efforts associated with water development programs.
Studies of wildlife and livestock interactions or interspecific competitions have yielded results that may well be applicable to the effects of water developments at varying extents and intensities. The following statements, relative to a variety of habitats and representing a variety of species, are presented for comparative purposes:
While there are few if any scientific studies that specifically address the impacts of livestock water developments on wildlife, some very important observations regarding water developments and impacts to wildlife (or wildlife habitats) appear in published literature:
Obviously, water developments have the potential to seriously impact wildlife as well as wildlife habitats. State and federal agencies typically incorporate a number of wildlife-related directives within their various standards and guides, planning, and operating documents. Some of the critical factors for wildlife in relation to livestock water developments are water access and escape or safety measures. Wildlife access and escape issues will be presented in great detail within subsequent report sections: Section 4.1 Wildlife Access, Safety Issues Related to Livestock Water Developments; and Section 4.2 Examples of Failures to Construct, Maintain Wildlife-Friendly Developments. A few examples of livestock developments and escape or access/availability issues will be included within this report subsection for informational and comparison purposes.
Sample excerpts from agency planning or operating manuals and other public documents include the following language regarding livestock and wildlife interactions or management protocol:
As with management for other ecosystem values, "paper" plans relating to wildlife values may not see effective implementation. Figures 3.1-50 through 3.1-82 (from public rangelands in Idaho, Nevada, and Utah) allow the reader/viewer to compare samples of actual field conditions with the above samples of agency management directives for the protection or enhancement of wildlife and wildlife habitat values (some photos may have been used in prior sections).
The figures in this section provide only the barest representative sampling of the thousands of wildlife habitat locations in the west that have been impacted by domestic livestock water developments. In the interests of time and space, these photos have been selected simply to show a wide range of the types of impacts that may result from livestock water developments and to represent concerns specific to water or other range developments.
The wildlife habitat values of the pictured seeps, springs, riparian zones, and upland habitats have been seriously impaired. Wildlife forage values, cover values (nesting, hiding, escape, thermal, and other types of cover), prey base values (such as forage or reproductive cover), and other required wildlife habitat values have been severely impacted or are missing entirely. Local as well as regional wildlife populations may be seriously or irreversibly impacted by a lack of nesting or escape cover, the lack of forage, and other habitat impairments. Many wildlife species, both invertebrate and vertebrate species are riparian or aquatic obligate or dependent species. With the loss of the natural spring or other surface water flows- riparian and aquatic species may have been completely extirpated from many if not most impacted locations. Most of the above photographs were taken within habitats that have been historically utilized by sage grouse, lynx, and other sensitive, threatened, or endangered species. Such impacts cannot help but make a continuing impact on whatever wildlife values still remain on our western rangelands.
The kinds of impacts represented by these field photographs are readily observable to any area visitor- from agency personnel and permittees to the recreating public. Yet public planning documents produced by our various agencies continue to propose that wildlife values are one of the benefits of livestock range improvements- including from water developments. This issue is discussed in more detail in Section 5.1, Water Developments: Why They Represent Violations of the Public Trust. As was noted previously, the next report sections Section 4.1 and 4.2 will discuss the issue of wildlife escapes (and management failures to provide escapes) in greater detail.
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