Management affects rangeland resources over time

Management affects rangeland resources over time

A HEALTHY agro-ecosystem is critical to productive, stable rangeland, and land managers who are trying to restore an ecosystem and productivity must understand that it requires a different process of allocating resources under differing situations, according to Texas A&M AgriLife Research ecologist Dr. Richard Teague.

Teague, AgriLife Research rangeland ecology and management scientist in Vernon, Texas, is developing a database that can aid producers in calculating how different management techniques will provide the best and most sustainable resource and economic results.

In his study, Teague is measuring and documenting the effects of different range management strategies on critical natural resources. To improve their situation, he said, landowners must first understand what is necessary to make changes.

"We are studying how conservation award-winning ranch managers do it," Teague said. "In the process, we are also finding that ranchers who have improved the condition of the range vegetation and soils have increased productivity and have been less impacted by the bad drought we are currently experiencing."

The Texas section of the Society for Range Management recently presented the conservation ranch award to a rancher who uses a very simple four-pasture management strategy with a growing season rest every three to four years, Teague said.

The rancher achieved good conservation, productivity and economic results despite the bad drought — an excellent example of the successful use of planned, time-controlled grazing that every rancher would find very easy to manage, he noted.

"If you look at successful managers, the leading people exceed the average by a margin, and they do that by the way they allocate resources, use different techniques and adapt as things change," Teague said.

He said his studies, which are on the landscape level instead of the small plot level, are taking place on ranches with similar vegetation, most of them east of Wichita Falls, Texas. Ranches in three contiguous counties with award-winning management were selected.

The study is examining the impacts of changing key management elements and planning ahead to decrease the effects of different circumstances such as dry or wet seasons, wildfires and changing weather patterns. It is designed to answer questions such as: "How good is any management option ecologically, economically and socially?" and "Within what context is it most likely to be successful?"

Teague said his study aims to determine what combination of management choices yields superior results.

"We want to test the impact of different grazing management strategies at the scale of commercial ranches by studying impacts on neighboring ranches to check for consistency of response across multiple counties," Teague said.

He said superior results in terms of range improvement, productivity and profitability also have been regularly obtained by ranchers who use many more paddocks per herd with shorter periods of grazing and who are adaptively changing recovery periods and other management elements as conditions change.

Teague said good managers deal with complexity and do not become overwhelmed by it.

"I've developed five different sets of decision rules that result in five different levels of management complexity. We are trying to find the minimum number of key decisions that will result in the most satisfactory resource and economic results," Teague explained.

"We compare the results of these sets of decision rules with results achieved by ranchers who have made these different sets of decisions to make sure we are incorporating local knowledge and experience," he said.

An important tool that has been refined recently is using aerial monitoring of ranch landscapes, Teague said.

Landscape data have been available for 20-plus years via the National Aeronautics & Space Administration's LANDSAT program, "so we can examine the impacts of different ranch management decisions retrospectively over whole ranch landscapes," he said.

"You can't just monitor management impacts on an ecosystem over a couple years; you need to go through at least two wet and two dry cycles before you can begin to understand what impacts that management really causes, and three would actually be better," he added.

"These retrospective analyses will enable us to see how neighbors who manage differently were impacted during both dry and wet years relative to each other. This is particularly important so we can check what management decisions result, over the years, in a rancher being able to minimize the impacts of droughts while taking advantage of the good years when they happen," Teague said.

 

Complex landscapes

Grazing management that extends the vitality of rangelands and ensures the best food sources for livestock is not a new concept, but recognizing that there are not "rules of thumb" that can be applied everywhere is new.

A special issue of the journal Rangelands explores strategic grazing management for complex systems, an issue first discussed in a 2008 symposium and further addressed in presentations at a 2012 symposium, both in Colorado.

This issue brings together ideas that emerged from these meetings and attempts to resolve questions using a combination of scientific theory and case studies, an announcement from the Society for Range Management, the journal's publisher, said.

As landscapes transform, strategic management must change alongside them. As the authors of the issue's lead article pointed out, organisms are not so much adapting to change but actively participating in creating new environments — even if it is not always to the advantage of a particular organism.

Another aspect of grazing management addressed in this special issue is stocking rates. One article recommends that stocking rates be determined independent of a ranch's fixed costs, suggesting a formula of variable costs and the value of production. Another article focuses on stocking rates and rainfall, offering examples from Texas of rate adjustments to accommodate very dry and very wet years.

Additional articles describe necessary plant recovery periods, including seasonal variations and understanding animal behavior and interactions with a diversity of resources. Philosophies and practices of spatial distribution on the landscape and increased stocking densities are also presented.

 

Cattle origins

An international team of researchers, co-led by scientists at the University of York in the U.K. and Yunnan Normal University in China, has produced the first multidisciplinary evidence for management of cattle populations in northern China around the same time cattle domestication took place in the Near East more than 10,000 years ago.

The domestication of cattle is a key achievement in human history. Until now, researchers believed that people started domesticating cattle around 10,000 years ago in the Near East, which gave rise to humpless (taurine) cattle, while 2,000 years later, people began managing humped cattle (zebu) in southern Asia.

However, the new research, which is published in Nature Communications, revealed morphological and genetic evidence for management of cattle in northeastern China roughly 10,000 years ago, around the same time the first domestication of taurine cattle took place in the Near East. This indicates that humans may have started domesticating cows in more regions around the world than was previously believed.

The lower jaw of an ancient cattle specimen was discovered during an excavation in northeast China and was carbon dated to be 10,660 years old. The jaw displayed a unique pattern of wear on the molars, which, the researchers said, is best explained to be the result of long-term human management of the animal.

Ancient DNA from the jaw revealed that the animal did not belong to the same cattle lineages that were domesticated in the Near East and South Asia.

Research co-leader professor Michi Hofreiter of the University of York said, "The specimen is unique and suggests that, similar to other species such as pigs and dogs, cattle domestication was probably also a complex process rather than a sudden event."

Volume:85 Issue:47

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