CHAPTER 14 GRASSLANDS RESTORING THE RANGE The key to recovering
the worlds grasslands may be a surprising one
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14 Main Concept RESTORING THE RANGE RESTORING THE RANGE The key
to recovering the worlds grasslands may be a surprising one
Grasslands offer important ecosystem services that are used for
grazing all over the world. Desertification caused by overgrazing
is the most common problem facing grasslands, but they can be
protected through innovative livestock practices.
Slide 3
Learning Outcomes At the end of this chapter you should know:
There are many types and locations of grasslands around the world.
The importance of grasslands is compromised by over- and
undergrazing. We can manage grasslands to lessen the threat and
maintain productivity.14 RESTORING THE RANGE RESTORING THE RANGE
The key to recovering the worlds grasslands may be a surprising
one
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14 Cattle and goats have pulverized the drought- prone Omo in
Ethiopia into dust. Issue: Climate change and grazing are changing
prairie grasslands into desert. Problems are similar around the
world, as 70% of the worlds rangelandabout one-third of the Earths
entire land surface is threatened by desertification. Ecological
cascade Plants die, soil erodes, prairies fail, famines set in,
economies falter, societies fail. Case study: Horse Creek Ranch in
South Dakota grazing more cattle to save the prairie.
Slide 5
Grasslands provide a wide range of important goods and
services14 Grasslands are biomes that receive enough rainfall to
support grass and herbaceous plants, but not enough to support
forests. They may also be found in regions with plentiful rainfall,
but periodic fires and grazing herbivores keep larger plants from
dominating. TERMS TO KNOW: Rangeland Desertification Overgrazing
Conservation reserve program Grasslands
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Grasslands provide a wide range of important goods and
services14 Threats to grasslands come from: Climate change Human
land-use decisions Overgrazing Herbivores have traditionally been
good for grasslands: Herbivores evolved with the grasslands and can
subsist on grasslands alone. Grasses grow from the base upwardby
clipping off the top part of the blade, new growth and shoots are
stimulated to grow by exposure to light. Soil broken by the
herbivores hooves allows water to penetrate the ground. Waste from
the animals provides nitrogen and phosphorus to fertilize the
grasses.
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Grasslands provide a wide range of important goods and
services14 Ecosystem services from grasslands: Wildlife habitat,
grazing, biomass, nutrient cycling, soil formation, carbon
sequestration, protection of surface waters Herbivores have now
overgrazed most of the worlds grasslands: With overgrazing, the
growth area of the grass blade is destroyed. If the blade cant
regenerate, the plant dies. There are no plants to hold soil in
place and frequent stomping of hooves compacts the soil. Water cant
penetrate compacted soil. Seeds cant germinate or grow. Increased
rates of erosion. Ecosystem services are lost.
Slide 8
Grasslands face a variety of human and natural threats14 Every
inhabited continent has grasslands vulnerable to desertification,
especially in arid areas close to existing deserts. Grasses are
adapted to grazing: Cropping the grass stimulates the growth area
at the base of the blade. Overgrazing may remove this growth area
and kill grasses, increasing the potential for
desertification.
Slide 9
Grasslands face a variety of human and natural threats TERMS TO
KNOW: Herbivore Soil erosion14 Continued ecological cascade
following erosiondenuded landscape reflects incoming sunlight,
altering wind and temperature patterns. Tragedy of the Commons
example from American historysettlers and their overgrazing left no
grass to hold the soil in place when the next drought came through.
Native prairie grasses have roots up to 16 feet long, which allow
them to access deep water supplies during droughts. The roots also
hold the soil in place much better than shallow-rooted crops.
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Grasslands face a variety of human and natural threats TERMS TO
KNOW: Herbivore Soil erosion14 Continued ecological cascade
following erosiondenuded landscape reflects incoming sunlight,
altering wind and temperature patterns. Tragedy of the Commons
example from American history settlers and their overgrazing left
no grass to hold the soil in place when the next drought came
through.
Slide 11
Grasslands face a variety of human and natural threats TERMS TO
KNOW: Herbivore Soil erosion14 Soil is produced by the decay of
organic material and the weathering of rock. Distinct layers are
seen in healthy soils with the topsoil (A horizon) being the most
fertile for plant growth. Desertification will reduce or remove the
O and A horizon and produce drier B and C horizons.
Slide 12
Grasslands face a variety of human and natural threats TERMS TO
KNOW: Herbivore Soil erosion14 Grassland degradation has cost
humans about 12% of global grain production, $23 billion in global
GDP, and has threatened the food supply of more than one billion
people.
Slide 13
Taking our cues from nature, we can learn to use rangelands
sustainably14 TERMS TO KNOW: Pastoralists Biologist Allan Savory
and the African Center for Holistic Management (ACHM) In the two
decades since ACHM was established, wild and domestic herds have
returned to graze, plants have rebounded, water is plentiful, and
livestock have increased by 400%. Wild herds grazed intensively and
then moved on. They grazed in tight groups to avoid predation and
didnt move back to any one area until the dung had been absorbed
and the grasses had recovered. Pastoralists had mimicked this
strategy, but nineteenth-century ranchers didnt.
Slide 14
Taking our cues from nature, we can learn to use rangelands
sustainably14 TERMS TO KNOW: Pastoralists Biologist Allan Savory
and the African Center for Holistic Management (ACHM) In the two
decades since ACHM was established, wild and domestic herds have
returned to graze, plants have rebounded, water is plentiful, and
livestock have increased by 400%. Livestock allowed to stay on a
pasture too long will damage the plants, which slows or prevents
recovery.
Slide 15
Taking our cues from nature, we can learn to use rangelands
sustainably14 TERMS TO KNOW: Pastoralists Undergrazing also comes
with problems. Without herbivores to eat the grasses, sunlight isnt
able to reach the growth buds and grasses die. Nutrients are then
processed by soil microbes rather than by the animals digestive
tracts. Animals become more selective, choosing only the sweetest
plants and leaving the weeds to prosper.
Slide 16
Taking our cues from nature, we can learn to use rangelands
sustainably14 TERMS TO KNOW: Pastoralists Experiments in biomimicry
led the scientist and local ranchers to try something different in
the face of government recommendation, failure, and desperation.
All the livestock were pulled together in a small paddock for
grazing for only a couple days before moving to the next paddock.
The first paddock was tuned into lumps of soil, dung, and freshly
exposed growth buds. By the time the cattle reached the last
paddock, they were ready for market and all the paddocks would have
an entire season to recover.
Slide 17
Taking our cues from nature, we can learn to use rangelands
sustainably14 TERMS TO KNOW: Pastoralists Experiments in biomimicry
led the scientist and local ranchers to try something different in
the face of government recommendation, failure, and desperation.
All the livestock were pulled together in a small paddock for
grazing for only a couple days before moving to the next paddock.
The first paddock was tuned into lumps of soil, dung, and freshly
exposed growth buds. By the time the cattle reached the last
paddock, they were ready for market and all the paddocks would have
an entire season to recover.
Slide 18
Taking our cues from nature, we can learn to use rangelands
sustainably14 TERMS TO KNOW: Pastoralists Experiments in biomimicry
led the scientist and local ranchers to try something different in
the face of government recommendation, failure, and desperation.
All the livestock were pulled together in a small paddock for
grazing for only a couple days before moving to the next paddock.
The first paddock was tuned into lumps of soil, dung, and freshly
exposed growth buds. By the time the cattle reached the last
paddock, they were ready for market and all the paddocks would have
an entire season to recover.
Slide 19
Taking our cues from nature, we can learn to use rangelands
sustainably14 TERMS TO KNOW: Pastoralists An important but under-
realized reality is that the more animals on a site, the less
selective they are able to become. With high animal density and
competition for nutrients, the herbivores will eat whatever is
available. Destructive grazing is an issue of time at the grazing
site more than the number of animals there.
Slide 20
Counteracting overgrazing requires careful planning14 TERMS TO
KNOW: Herbivore Soil erosion Livestock are allowed to graze
intensively on a plot and then are moved to the next plot. In this
example, each plot is grazed for one month. By the time they return
to a given plot, it will have recovered. With careful planning, a
third- generation rancher in South Dakota works around water
availability, bloom cycles of poisonous plants, migration patterns
of wild animals, and the reproductive cycle of parasites. All
plants, not just the sweetest, are grazed equally. The best-tasting
plants dont waste energy on chemical defenses, and biomass levels
are kept at an ideal range.
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Planning grazing is tricky work14 TERMS TO KNOW: Rotational
grazing Sustainable grazing Some ranchers argue that existing
methods of continuous grazing work just as well as sustainable
grazing when done properly and are easier to manage. Improved
grazing techniques can help protect and even restore some degraded
grasslands. A shelterbelt of trees may be able to hold back the
Gobi Desert and keep the farmland fertile.
Slide 22
Planning grazing is tricky work14 Ranching is a culture,
steeped in tradition. But our lands are hurting and our communities
are dying, and we know weve got to do something to fix that. Joe
Morris, California rancher Other approaches also help preserve
grasslands by limiting land uses and making it easier to keep the
land in some level of protected status.
Slide 23
Planning grazing is tricky work14 Ranching is a culture,
steeped in tradition. But our lands are hurting and our communities
are dying, and we know weve got to do something to fix that. Joe
Morris, California rancher Other approaches also help preserve
grasslands by limiting land uses and making it easier to keep the
land in some level of protected status.
Slide 24
Planning grazing is tricky work14 Ranching is a culture,
steeped in tradition. But our lands are hurting and our communities
are dying, and we know weve got to do something to fix that. Joe
Morris, California rancher Other approaches also help preserve
grasslands by limiting land uses and making it easier to keep the
land in some level of protected status.
Slide 25
Planning grazing is tricky work14 Ranching is a culture,
steeped in tradition. But our lands are hurting and our communities
are dying, and we know weve got to do something to fix that. Joe
Morris, California rancher Other approaches also help preserve
grasslands by limiting land uses and making it easier to keep the
land in some level of protected status.
Slide 26
Planning grazing is tricky work14 Ranching is a culture,
steeped in tradition. But our lands are hurting and our communities
are dying, and we know weve got to do something to fix that. Joe
Morris, California rancher Other approaches also help preserve
grasslands by limiting land uses and making it easier to keep the
land in some level of protected status.
