According to Wikipedia, an ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (air, water and mineral soil) interacting as a system.

Fears robert
Freelance Writer
Robert Fears is a freelance writer based in Georgetown, Texas.

Interactions within an ecosystem are not understood by some land managers, and they are definitely not known by most bureaucrats and citizen groups who demand policies that do more harm to our environment than good.

One component of an ecosystem cannot be altered without affecting the other parts. In restoring our lands from drought effects, we must consider the entire ecosystem in order to be successful.

Cow and calf

“As pasture-based livestock producers, we are in the business of harvesting solar energy and converting it to food and fiber products for people,” says Edward Rayburn, West Virginia University Extension Service.

“We manage plants to optimize solar energy harvest, feed animals so that they can transfer that energy into livestock products, and to cycle mineral nutrients in the landscape. These processes are necessary to make our businesses socially, economically and environmentally sustainable. We are pasture ecosystem managers.

Advertisement

“Most of our day-to-day efforts are spent with livestock, managing the above-ground portion of the pasture community to ensure that the animals are properly fed. However, there is more biomass and biological activity below-ground than above.

“Every plant, animal, bacteria, protozoa and fungus has its niche or place in the pasture ecosystem,” Rayburn continues. “Each has an optimum physical and chemical environment and habitat. The habitat provides adequate food and cover, allowing the species to reproduce and maintain itself. Environment is based on climate, time of year, soil texture, position in the landscape and management.”

“Healthy agri-ecosystems are considerably more productive, stable and resilient than those in poor condition,” says Richard Teague, Texas A&M AgriLife Research.

“Ranch livelihoods depend on healthy ecosystems, and value of ecosystem services is worth more to society than agricultural earnings.”

Forage management

cattle in a paddockTeague and others have researched the use of planned multi-paddock grazing for restoring range ecosystems. They have learned that putting a large number of cattle in a paddock for a short period of time causes the animals to graze more of the whole landscape and to select a wider variety of plant species.

This grazing system allows the manager to regulate how much is grazed, the period of grazing and length and time of recovery from grazing.

“Achieving desired outcomes of multi-paddock grazing include the match of animal numbers to available forage and the spread of grazing over the entire ranch,” says Teague.

“Forage needs to be defoliated moderately during the growing season with short grazing periods. Adequate recovery is allowed prior to regrazing, but paddocks are grazed again before forage becomes too mature to be palatable.

To achieve desired outcomes, it is very important to adjust the multi-paddock grazing elements in response to changing weather and other conditions.”

Soil management

Forage as well as other plants can be as healthy as the soil in which they grow. As part of the ecosystem, plants depend upon soil for anchorage, oxygen, water, temperature moderation and nutrients.

Plants interact with specific soil microbes by releasing carbohydrates through their roots into the soil to feed microbes in exchange for nutrients and water.

Ninety percent of soil function is mediated by microbes which depend on plants, so how we manage plants is critical.

“The spaces among soil particles contain air that provides oxygen, which living cells (including root cells) use to break down sugars and release the energy needed to live and grow,” says Lois Stack, University of Maine Cooperative Extension.

“Soil spaces also contain water, which moves upward through plants. This water cools plants as it evaporates off the leaves and other tissues, carries essential nutrients into plants, helps maintain cell size so that plants don’t wilt and serves as a raw material in photosynthesis.

cattle grazing

Soil insulates roots from drastic fluctuations in temperature, which is especially important during excessively hot or cold times of the year. In addition, soil supplies nutrients and holds the nutrients to keep them available to plants.”

According to USDA-NRCS, management for soil health and improved soil function is mostly a matter of maintaining suitable habitat for the myriad of creatures that comprise the soil food web.

This can be accomplished by disturbing soil as little as possible, growing as many different plant species as practical, keeping living plants in the soil for as many days during the year as possible and keeping soil covered all the time. Avoiding the overgrazing of pastures provides constant soil cover.

Water management

Ranchers who are good land stewards have a favorite saying: “I don’t want my neighbors’ water – I just want to keep what falls on my place.” These people are saying that one of their primary goals is to maintain enough pasture vegetation to catch as much precipitation as possible for infiltration into the soil.

The NRCS defines infiltration as the process of water soaking into the soil. Infiltration rate is simply how fast water enters the soil and is usually measured in inches or millimeters per hour.

This rate depends on soil texture (amount of sand, silt and clay) and on soil structure, which is the way individual particles of sand, silt and clay are assembled. Soils in good condition have well-developed structure and continuous pores to the surface. As a result, water from rainfall or snowmelt readily enters these soils.

“Soil is a reservoir that stores water for plant growth,” says the NRCS. “The water in soil is replenished by infiltration. Poor management can restrict infiltration rate where water does not readily enter the soil."

"Instead it moves downslope as runoff or ponds on the surface to evaporate. Thus, less water is stored in the soil for plant growth, and plant production decreases."

"This results in less organic matter in the soil and weakened soil structure that can further decrease infiltration rate."

“Runoff can cause soil erosion and formation of gullies. It also carries nutrients and organic matter which, together with sediment, reduces water quality in streams, rivers and lakes."

"Sediment reduces capacity of reservoirs to store water. Excessive runoff can cause flooding, erode stream banks and damage roads. Runoff from adjacent slopes can saturate soils in low areas or create ponded areas, thus killing upland plants. Evaporation in ponded areas reduces the amount of water available to plants.”

“Ecosystem structure and function is influenced by infiltration rate, soil moisture storage capability, precipitation characteristics and rain-use efficiency,” says Thomas Thurow, University of Wyoming.

“The degree to which these hydrologic attributes are affected by land use determines the impact of land use on the ecosystem. Simply removing the initial cause of degradation may not restore the site’s production potential and may not even break the pattern of decline if a self-sustaining cycle of deterioration has developed."

"Reasons why severely disturbed landscapes may not recover production potential include loss of species, altered species interactions, physical degradation of hydrologic characteristics or nutrient depletion.”

According to the NRCS, soil and vegetation properties that currently limit infiltration and the potential for an increased rate must be considered in any management plan.

Where water flow patterns have been altered by a shift in vegetation, such as a shift from grassland to open-canopy shrub land, restoration of higher infiltration rates may be difficult or take a long period of time.

This is especially true if depletion of organic matter or soil loss have occurred. Excessive grazing of forage can impair infiltration while regenerative grazing management can restore infiltration and reduce runoff and erosion.

The NRCS suggests the following management strategies for rangeland restoration:

  • Increase amount of plant cover, especially of plants that have positive effects on infiltration.

  • Decrease extent of compaction by avoiding intensive grazing and use of machinery when soils are wet.

  • Decrease formation of physical crusts by maintaining or improving the cover of plants or litter and thus reducing the impact of raindrops.

  • Increase aggregate stability by increasing the amount of organic matter added to the soil through residue decomposition and vigorous root growth.

These management systems can only be accomplished through a planned grazing system that prevents overgrazing. end mark

Robert Fears is a freelance writer based in Texas.

PHOTOS
PHOTO 1: Planned grazing is a good way to restore range ecosystems from the effects of drought.

PHOTO 2: An animal unit is a 1,000- pound cow with a suckling calf.

PHOTO 3: A large number of cattle in a paddock for a short period of time causes the animals to graze more of the whole landscape.

PHOTO 4: Overgrazing degrades the entire pasture ecosystem. Photos courtesy of Robert Fears.