CHAPTER 14 GRASSLANDS RESTORING THE RANGE The key to recovering the world’s grasslands may be a...

CHAPTER 14 GRASSLANDS

RESTORING THE RANGEThe key to recovering the world’s grasslands may be a surprising one

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Main Concept

RESTORING THE RANGEThe key to recovering the world’s 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.

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 RANGEThe key to recovering the world’s grasslands may be a surprising one

RESTORING THE RANGEThe key to recovering the world’s grasslands may be a surprising one14

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 world’s rangeland—about one-third of the Earth’s 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.

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:RangelandDesertificationOvergrazingConservation reserve programGrasslands


Threats to grasslands come

from:

Climate changeHuman land-use

decisionsOvergrazing

Herbivores have traditionally been good for grasslands:

Herbivores evolved with the grasslands and can subsist on grasslands alone.

Grasses grow from the base upward—by 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.


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 world’s grasslands:

With overgrazing, the growth area of the grass blade is destroyed. If the blade can’t regenerate, the plant dies.

There are no plants to hold soil in place and frequent stomping of hooves compacts the soil.

Water can’t penetrate compacted soil.

Seeds can’t germinate or grow.

Increased rates of erosion.

Ecosystem services are lost.

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.

Grasslands face a variety of human and natural threats

TERMS TO KNOW:HerbivoreSoil erosion

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Continued ecological cascade following erosion—denuded 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.

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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Continued ecological cascade following erosion—denuded landscape reflects incoming sunlight, altering wind and temperature patterns.Tragedy of the Commons example from American history—settlers and theirovergrazing left no grass to hold the soil in place when the next drought came through.



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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.



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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.

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 didn’t 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 didn’t.



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.



Undergrazing also comes with problems. Without herbivores to eat the grasses, sunlight isn’t 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.



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.



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.

Counteracting overgrazing requires careful planning14TERMS TO KNOW:HerbivoreSoil 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 don’t waste energy on chemical defenses, and biomass levels are kept at an ideal range.

Planning grazing is tricky work14TERMS TO KNOW:Rotational grazingSustainable 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.

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 we’ve 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.

PERSONAL CHOICES THAT HELP14

UNDERSTANDING THE ISSUE14

ANALYZING THE SCIENCE14

EVALUATING NEW INFORMATION14

www.eatwild.com

MAKING CONNECTIONS14

CHAPTER 14 GRASSLANDS RESTORING THE RANGE The key to recovering the world’s grasslands may be a...

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