Conservation Grazing
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Conservation grazing or targeted grazing is the use of semi- feral or domesticated
grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and ot ...
livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to ani ...
to maintain and increase the
biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic ('' genetic variability''), species ('' species diversity''), and ecosystem ('' ecosystem diversity'') ...
of natural or semi-natural
grassland A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...
s,
heathland A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a coole ...
s, wood pasture,
wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (Anoxic waters, anoxic) processes prevailing, especially in t ...
s and many other
habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
s. Conservation Grazing
Peninsula Open Space Trust, California, US, 2009. (cited 2009 Mar 11)
What is Conservation Grazing?
Grazing Advice Partnership, UK, 2009.
Conservation grazing is generally less intensive than practices such as prescribed burning, but still needs to be managed to ensure that
overgrazing Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature res ...
does not occur. The practice has proven to be beneficial in moderation in restoring and maintaining grassland and heathland
ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syst ...
s. The optimal level of grazing will depend on the goal of conservation, and different levels of grazing, alongside other conservation practices, can be used to induce the desired results.


History

For historic
grassland A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...
s, grazing animals,
herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...
s, were a crucial part of the ecosystem. When grazers are removed, historically grazed lands may show a decline in both the density and the diversity of the vegetation. The history of the land may help ecologists and conservationists determine the best approach to a conservation project.History distribution and challenges to bison recovery in the northern Chihuahuan desert
''Rurik, L., G. Ceballos, C. Curtin, P. J. P. Gogan, J. Pacheco, and J. Truett''. Conservation Biology, 2007, 21(6): 1487-1494.
Historic threats to grasslands began with land conversion to crop fields. This shifted to improper land management techniques and more recently to the spread of woody plants due to a lack of management and to
climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
.An ecosystem in transition: causes and consequences of the conversion of Mesic grassland to shrubland ''Briggs, J. M., A. K. Knapp, J. L. Heisler, J. M. Blair, M. S. Lett, G. A. Hoch and J. K. McCarron''. Bioscience, 2005, 55(3): 243-254.


Conservation grazing in practice

Intensive
grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and ot ...
maintains an area as a habitat dominated by grasses and small shrubs, largely preventing
ecological succession Ecological succession is the process of change in the species structure of an ecological community over time. The time scale can be decades (for example, after a wildfire) or more or less. Bacteria allows for the cycling of nutrients such as car ...
to forest.Influence of cattle grazing practices on forest understory structure in North-eastern New South Wales
''Tasker, E M and R A Bradstock''. Austral Ecology, 2006, 31(4): 490-502.
Extensive grazing also treats habitats dominated by grasses and small shrubs but does not prevent succession to forest, it only slows it down. Conservation grazing is usually done with extensive grazing because of the ecological disadvantages of intensive grazing. Conservation grazing needs to be monitored closely. Overgrazing may cause
erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is d ...
, habitat destruction,
soil compaction In geotechnical engineering, soil compaction is the process in which stress applied to a soil causes densification as air is displaced from the pores between the soil grains. When stress is applied that causes densification due to water (or othe ...
, or reduced biodiversity ( species richness).Effects of Grazing on the demography and growth of the Texas tortoise ''Kazmaier, R.T., E.C. Hellgren, D.C. Ruthven III, and D.K. Synatzske''. Conservation Biology, 2002, 15(4): 1091-1101. ''Rambo and Faeth'' found that the use of vertebrates for grazing of an area increased the species richness of plants by decreasing the abundance of
dominant species Ecological dominance is the degree to which one or several species have a major influence controlling the other species in their ecological community (because of their large size, population, productivity, or related factors) or make up more of ...
and increasing the richness of rarer species. This may lead to a more open forest canopy and more room for other plant species to emerge.Effect of Vertebrate Grazing on Plant and Insect Community Structure
''Rambo, J.L and S.H. Faeth''. Conservation Biology, 2001, 13(5): 1047-1054.


Grazing restoration effect dependent on grazer species

Different grazing species have different effects. For example, elk and horses have a similar grazing frequency to cattle but tend to spread their zone of grazing to cover a greater area, producing a smaller effect on a given area than cattle would.Differing Effects of Cattle Grazing on Native and Alien Plants
''Kimball, S. and P.M Schiffman''. Conservation Biology, 2003, 17(6): 1681-1693.
Similarly, cattle have been found to be more useful in the restoration of pastures with low species richness, and sheep were found useful for the re-establishment of neglected fields.Effects of livestock breed and grazing intensity on grazing systems: 3. Diversity of Vegetation
''Scimone, M., A.J. Rook, J.D. Gavel, and N. Sahin''. Grass and Forage Science, 2007, 62(2): 172-184.
The type of area that needs to be restored or maintained will determine the species of grazer ideal for conservation grazing. ''Dumont et al.''Effects of livestock breed and grazing intensity on biodiversity and production in grazing systems and diet selection: 2. Diet systems
''Dumont, B., A.J. Rook, Ch. Coran, and K.U. Rover''. Grass and Forage Science, 2007, 62(2): 159-171.
found in the use of varied breeds of steers that "traditional breeds appeared slightly less selective than commercial breeds", but did not make a significant difference in biodiversity. In this particular study biodiversity was maintained by the same amount by both breed types.


Effects on native and non-native plant species

Conservation grazing is a tool used for conserving biodiversity. However, one danger in grazing is the potential for
invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...
to be enhanced as well as the native
biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic ('' genetic variability''), species ('' species diversity''), and ecosystem ('' ecosystem diversity'') ...
. A study by ''Loeser et al.'' showed that areas of high intensity grazing and grazer removal increased the
biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...
of nonnative
introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...
. Both showed that an intermediate approach is the best method. The nonnatives did demonstrate that they were not as well adapted to the
disturbance Disturbance and its variants may refer to: Math and science * Disturbance (ecology), a temporary change in average environmental conditions that causes a pronounced change in an ecosystem * Disturbance (geology), linear zone of faults and folds ...
s, such as
drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D.  Jiang, A.  Khan, W.  Pokam Mba, D.  Rosenfeld, J. Tierney, an ...
. This indicated that implementing controlled grazing methods would decrease the abundance of nonnatives in those plots that had not been properly managed.Impact of grazing intensity during Drought in an Arizona Grassland
''Loeser, M R R, T D Sisk, and T E Creus''. Conservation Biology, 2006, 21(1): 87-97.
Effects of grazing can also depend on the individual plant species and its response to grazing. Plants that are adapted to extensive grazing (such as that done by cattle) will respond quicker and more effectively to grazing than native species that have not had to cope with intense grazing pressure in the past. An experiment done by Kimball and Schiffman showed that grazing increased the cover of some
native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...
species but did not decrease the cover of nonnative species. The species diversity of the native plants was able to respond to the grazing and increase diversity. The community would become denser than originally with the increased biodiversity. (However, this may have been simply variance in plots due to the fact that the native and nonnative compositions were of different species between the grazed and ungrazed plots.)


Effects on animals


Insects and butterflies

Degree of grazing has a significant effect on the species richness and abundance of insects in grasslands. Land management in the form of grazing tends to decrease diversity with increased intensity. Kruess and Tscharntke attribute this difference to the increased height of grasses in the ungrazed areas. The study showed that the abundance and
diversity of insects Insect biodiversity accounts for a large proportion of all biodiversity on the planet—over half of the estimated 1.5 million organism species described are classified as insects. Species diversity Estimates of the total number of insect species ...
(such as butterfly adults, trap-nesting bees and wasps) were increased by increased grass height. However, other insects such as grasshoppers responded better to
heterogeneity Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, siz ...
of the vegetation.Grazing Intensity and the Diversity of Grasshoppers, Butterflies, Trap-Nesting Bees and Wasps
''Kruess, A. and T. Tscharntke''. Conservation Biology, 2002, 16(6): 1570-1580.


Vertebrates

Grazing can have varied effects on vertebrates. Kuhnert et al. observed that different bird species react in different ways to changes in grazing intensity.Assessing the Impacts of grazing levels on bird density in woodland habitat: a Bayesian approach using expert opinion
''Kuhnert, P.M, T.G. Martin, K. Mengersen, and H.P Possingham''. Environmetrics, 2005, 16(7): 717-747.
Grazing has also been thought to decrease the abundance of vertebrates, such as the
prairie dog Prairie dogs (genus ''Cynomys'') are herbivorous burrowing ground squirrels native to the grasslands of North America. Within the genus are five species: black-tailed, white-tailed, Gunnison's, Utah, and Mexican prairie dogs. In Mexico, p ...
and the
desert tortoise The desert tortoise (''Gopherus agassizii''), is a species of tortoise in the Family (biology), family Testudinidae. The species is native to the Mojave Desert, Mojave and Sonoran Deserts of the southwestern United States and northwestern Mexic ...
. However, Kazmaier et al. found that moderate grazing by cattle had no effect on the
Texas tortoise The Texas tortoise (''Gopherus berlandieri''), is a species of tortoise in the family Testudinidae. The species ''G. berlandieri'' is one of six species of tortoises that are native to North America. Geographic range ''G. berlandieri'' is found ...
. Rabbits have been widely discussed due to their influences on land composition. Bell and Watson found that rabbits show grazing preference for different plant species.Preferential grazing of five varieties of spring barley by wild rabbits (Oryctolagus cuniculus)
''Bell, A.C. and S. Watson''. Annals of Applied Biology, 2008, 122(3): 637-641.
This preference can alter the composition of a plant community.Key role of European rabbits in the conservation of the Western Mediterranean Basin Hotspot
''Delibes-Mateos, M., M. Delibes, P. Ferreras, and R. Villafuerte''. Conservation Biology, 2008, 22(5): 1106-1117.
In some cases, if the preference is for a non-native, invasive plant, rabbit grazing may benefit the community by reducing non-native abundance and creating room for the native plant species to fill.The Effects of herbivory and competition on the invasive alien plant Senecio inaequidens (asteraceae)
''Scherber, C., M.J. Crawley and S. Povembshi''. Diversity and Distributions, 2003, 9(6): 415-426.
When rabbits graze in moderation they can create a more complex ecosystem, by creating more variable environments that will allow for more predator-competitor relationships between the various organisms. However, besides the effect on wild vegetation, rabbits destroy crops, compete with other herbivores, and can result in extreme ecological damage. Competition can be direct or indirect. The rabbits may specifically eat the competitions target food or it may inhibit the growth of grasses that other species eat. For example, rabbit grazing in the Netherlands inhibits tall grasses from becoming dominant. This in turn enhances the suitability of the pasture for
brent goose The brant or brent goose (''Branta bernicla'') is a small goose of the genus '' Branta''. There are three subspecies, all of which winter along temperate-zone sea-coasts and breed on the high-Arctic tundra. The Brent oilfield was named after ...
. However, they may benefit predators that do better in open areas, because the rabbits reduce the amount of vegetation making it easier for those predators to spot their prey. Finally, grazing has demonstrated use in clearing dry brush to reduce the fire hazard of drought-stricken areas.


Effect on ephemeral wetlands

Ephemeral Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...
wetlands A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...
degradation and
loss of biodiversity Biodiversity loss includes the worldwide extinction of different species, as well as the local reduction or loss of species in a certain habitat, resulting in a loss of biological diversity. The latter phenomenon can be temporary or permanent, de ...
had, at one point in time, been blamed on mismanaged grazing of both native and non-native
ungulates Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, cam ...
and other grazers. A study done by Jaymee Marty of
The Nature Conservancy The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US. Founded in 1951, The Natu ...
examined the effects on the
vernal pools Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe ...
formed in California when grazers were removed.Effects of Cattle Grazing on Diversity in Ephemeral Wetlands
''Marty, J.T''. Conservation Biology, 2005, 19(5): 1626-1632.
The results of the short study showed that areas where grazers were removed had a lower diversity of native grasses, invertebrates and vertebrates in the pools, with an increase in non-native grass abundance and distribution in the area. The study also demonstrated reduced reproduction success of individual species in the area, such as the western spadefoot toad and
California tiger salamander The California tiger salamander (''Ambystoma californiense'') is a vulnerable amphibian native to California. It is a mole salamander. Previously considered to be a subspecies of the tiger salamander (''A. tigrinum)'', the California tiger salam ...
. Marty argues that this decrease is due to ecosystems adapting to historical changes in grazers and the effects they have. In other words, the historic ecosystem, theoretically, would have responded positively to the removal of cattle grazing, however, the system has adapted to the European introduced species and now may require them for maintained diversity. In another study performed by Pyke and Marty, measurements showed that on average, vernal ponds on grazed land pooled longer than ungrazed areas and soil was more resistant to water absorption in the grazed areas.Cattle grazing Mediates Climate change impacts on Ephemeral Wetlands
''Pyke, C.R. and J. Marty''. Conservation Biology, 2005, 19(5): 1619-1625.


Targeted grazing

A recent synonym or near-synonym for conservation grazing is "targeted grazing", a term introduced in a 2006 handbook in distinction to prescribed grazing, which the USDA
National Resource Conservation Service Natural Resources Conservation Service (NRCS), formerly known as the Soil Conservation Service (SCS), is an agency of the United States Department of Agriculture (USDA) that provides technical assistance to farmers and other private landowners and ...
was using to describe all managed grazing. Targeted grazing is often used in combination with other techniques such as burning, herbicide applications or land clearing. Targeted grazing can rival traditional herbicide and mechanical control methods for invasive plants from invasive forb to juniper trees, and has been used to reduce fine fuels in fire prone areas.


Principles

The most important skill for developing a targeted grazing program is patience and commitment. However, understanding livestock and plant responses to grazing are critical in developing a targeted grazing program. The program should have a clear statement of the kind of animal, timing and rate of grazing necessary to suppress troublesome plants and maintain a healthy landscape. The grazing application should 1) cause significant damage to the target plants 2) limit damage to desired vegetation and 3) be integrated with other control strategies. First, to cause significant damage to targeted plants requires understanding when the target plant is most susceptible to grazing damage and when they are most palatable to livestock. Target plant palatability depends on the grazing animals inherited and developed plant preferences (i.e. the shape of sheep and goat's mouths make them well suited for eating broad leaf weeds). Goats are also well designed for eating shrubs. Second, target plants often exist in a plant community with many desirable plants. The challenge is to select the correct animal, grazing time and grazing intensity to maximize the impact on the target plant while reducing it on the associated plant community. Finally, management objectives, target plant species, weather, topography, plant physiology, and associated plant communities are among the many variables that can determine treatment type and duration. Well-developed targeted grazing objectives and an
adaptive management Adaptive management, also known as adaptive resource management or adaptive environmental assessment and management, is a structured, iterative process of robust decision making in the face of uncertainty, with an aim to reducing uncertainty over ...
plan that takes into account other control strategies need to be in place.


See also

*
Epping Forest Epping Forest is a area of ancient woodland, and other established habitats, which straddles the border between Greater London and Essex. The main body of the forest stretches from Epping in the north, to Chingford on the edge of the London ...
*
New Forest The New Forest is one of the largest remaining tracts of unenclosed pasture land, heathland and forest in Southern England, covering southwest Hampshire and southeast Wiltshire. It was proclaimed a royal forest by William the Conqueror, featu ...
*
Oostvaardersplassen The Oostvaardersplassen () is a nature reserve in the Netherlands, managed by the ''Staatsbosbeheer'' (state forestry service). Covering about in the province of Flevoland, it is an experiment in rewilding.Oostvaardersplassen is discussed, for ex ...
*
Wood-pasture hypothesis The wood-pasture hypothesis, also known as the Vera hypothesis and the megaherbivore theory is a scientific hypothesis positing that open and semi-open pastures and wood-pastures formed and maintained by large wild herbivores, rather than primev ...
* Milovice Nature Reserve *
Holistic management (agriculture) Holistic Management (from ''holos'', a Greek word meaning ''all'', ''whole'', ''entire'', ''total'') in agriculture is an approach to managing resources that was originally developed by Allan Savory. Holistic Management is a registered tradem ...


References


External links

* * * *
Targeted Grazing YouTube channel

Society for Range Management Targeted Grazing Committee
{{DEFAULTSORT:Conservation Grazing Permaculture concepts Habitats Habitat management equipment and methods Ecological restoration Grasslands Livestock