Patterns in Rangeland Productivity and Land Ownership and What They Mean for Conservation

March 6, 2019

New research highlights trends in rangeland productivity across ownership types, making it easier to plan, implement, and monitor conservation projects. Photo: Tatiana Gettelman

Ask An Expert: Dr. Brady Allred, Associate Professor of Rangeland Ecology, University of Montana


Conservation will ultimately boil down to rewarding the private landowner who conserves the public interest. ~ Aldo Leopold, Conservation Economics, 1934 essay from The River of the Mother of God: and other Essays by Aldo Leopold


Let’s start with a really basic question. What are rangelands?

Rangelands are non-forested, uncultivated lands that are mostly made up of grasses, forbs, and shrubs.

Where are most of the rangelands in the U.S.?  

Rangelands make up approximately one-third of the lower 48 states. Nearly all of that is in the western half of the nation, spanning the Great Plains to the Pacific coast.

Why are these landscapes so important?

In the continental U.S., rangelands comprise about 35% of the landscape. On a global scale, rangelands make up nearly 40% of the Earth’s ice-free surface. So, scale is one reason. More importantly, they provide numerous ecosystem services, which are benefits that humans gain from ecosystems, including forage and fiber like meat and wool, livelihoods like ranching, and recreation activities like hunting and bird watching.

What is vegetation productivity and specifically, net primary productivity, as it relates to rangelands in the conterminous U.S.?

Ecologically, vegetation production is the conversion of solar energy into chemical energy through photosynthesis. Plants use that energy for their own metabolic processes and also to grow. Net primary production is the amount of energy that accumulates as plant biomass. Productivity is the rate of production over a given time period. Net primary productivity (NPP) is the rate of increase in plant biomass.

Now, that is the scientist in me speaking. When people think of rangeland productivity, they often think of how much grass or forage is produced during a single growing season or year. This is commonly measured locally by clipping and weighing vegetation and then expressed in pounds per acre (lbs/acre). Nearly everyone who has worked in rangelands is familiar with this, and it is fundamentally the same thing as net primary productivity.

Why focus on net primary productivity? In other words, why is quantifying NPP helpful in advancing our understanding of rangeland conservation in the U.S.?

Two specific reasons: 1) there are well established methods to measure productivity across broad geographies using satellite remote sensing, which removes the need to go out and clip plants on every acre of rangeland; and 2) it is an ecological building block, a measure of the ultimate source of energy for all terrestrial species, and it is a “supporting ecosystem service.” A supporting ecosystem service is one that other ecosystem services depend upon.  Measuring net primary productivity gives a little broader perspective than just forage available for grazing animals.

Figure_1_EcosystemServices

Ecosystem service categories as specified by the Millennium Ecosystem Assessment. Examples provided are relevant to rangelands and primary productivity, showing how primary productivity, as a supporting ecosystem service, is foundational for the provisional, regulating, and cultural services on rangelands.

Vegetation production is one of the greatest natural assets we have. Being able to quantify rangeland production across space and through time allows us to assess that resource directly. We can evaluate the impact of our management actions on productivity, to see if those actions are helpful or harmful. We can see how productivity is changing in response to conservation practices, drought, or other factors and then plan appropriately. At broad geographies, we can understand the patterns and trends of productivity and develop local, regional, or national conservation strategies to sustainably manage this asset.

Your study looked at the comparative levels of NPP across public lands (federal, state and local), tribal lands, and private lands. What did you find?

Across the Lower 48, we found that the productivity of privately owned rangelands more than doubled that of public and tribal rangelands. We also found that over the last 25 years, there are no meaningful trends in the change of productivity, regardless of ownership, indicating that rangeland productivity has been stable through the years.

Your results match what a lot of people have assumed over the years – that private rangelands are more productive (as a measure of NPP) than public rangelands. Does this mean that private rangelands are better managed than public ones?  

No, absolutely not. This work does not evaluate the management in any sort of way; it simply looks at the rangeland resource available. Those resources are influenced by a myriad of factors, including precipitation and soil. The patterns of productivity are also a function of how the western U.S. was settled: the more productive lands of the Great Plains were largely privatized, while much of the less productive land in the West incorporated into the federal estate or became tribal lands.

Figure_2_RangelandOwnershipUS

The distribution for rangelands across the coterminous United States (CONUS) showing the spatial patterns of (a) annual productivity and (b) land ownership. The heavy lines indicate the delineation of western states, Great Plains states, and eastern states.

How does knowing the NPP levels for different ownership regimes and geographies help land managers (public or private) better manage rangeland in the U.S.?

Separating out the ownership and geographies really enables us to better understand and execute cross-boundary conservation and management strategies. Knowing that the majority of rangeland productivity is owned and managed privately–by normal, everyday people just like you and me–can help us structure regional and national priorities to implement the right management, in the right place, with the right resources.

And of course, this will vary with location. In regions where public rangeland is dominant and interspersed with private or tribal holdings (e.g., the Intermountain West), cooperation will need to exist to conserve the vast acreage of public rangeland, and the higher productivity of private and tribal rangelands. In other areas where public land is largely absent (e.g., the Great Plains), it will be necessary to focus efforts entirely on private rangeland conservation.

Your team analyzed a huge amount of data about rangeland productivity in the US. Did you find any trends?

The droughts of 2011 and 2012 really stood out. Because the drought was largely in the Great Plains, the productivity of private rangelands took a very noticeable drop compared to public and tribal rangelands. It was fascinating to see it bounce right back though, regardless of ownership, indicating a very resilient system. By analyzing such a large amount of data over such a long time frame, our methods allowed us to easily quantify and illustrate this.

Figure_4_ProductivityTrendsTime

a) Total production and (b) average productivity for rangelands across CONUS, 1993–2017. Total production and average productivity are consistently higher on private lands than public and tribal lands. Dashed lines represent mean values through time. Despite noticeable interannual variability, there are no significant temporal trends at the CONUS scale.

There were also no meaningful trends–up or down–of rangeland productivity over the last 25 years. At this scale, rangeland productivity has been largely stable. There are ups and downs, due to better- or worse-than-average climate years, but things have stayed relatively the same.

Your study points out that maintaining rangeland productivity is about more than simply conserving acreage. Can you explain what you mean?

Conserving large tracts of rangeland is absolutely critical for conservation. That conservation can occur individually with one owner (private, public, or tribal) or through a collection of owners working together. But what our findings show is that acreage alone just doesn’t cut it. The quality of rangeland, not just the size, is equally important. In this case, the quality of rangeland is being assessed through productivity, and size or acreage doesn’t necessarily lead to productivity. It is important that our conservation strategies look at the system as a whole, and that we work cooperatively to conserve the high-quality rangeland.

What does all this mean for public and private land managers and for agencies like the NRCS that can tap into technical and financial resources that help conserve and improve rangeland?

I think it really highlights the importance of partnerships and cross-boundary conservation. That is, we want to work together to conserve the best of what we have, regardless of ownership. The degree of these partnerships will vary based on location. The NRCS works cooperatively with private landowners, public land agencies, and other conservation groups to put the best conservation practices in place.

I think it also highlights the critical aspect of privately owned, working lands conservation. Rangeland productivity is a primary driving force for all the ecosystem services that rangelands provide. The vast majority of that productivity occurs on privately owned rangelands, predominantly in the Great Plains. If we want to maintain those ecosystem services, we need to work directly with landowners to do so.

What is next for the datasets your team created and analyzed through this study?

We are currently putting the final touches on this dataset and plan to make it easily accessible through the Rangeland Analysis Platform (RAP) (https://rangelands.app/). Landowners, managers, and practitioners will be able to use it along with our other datasets to plan and evaluate their management actions. Basically, RAP will provide access to vegetation cover data, productivity data, and more. These datasets will make it more efficient and easier to design and implement projects and to monitor what those projects mean on the ground.

Meet the Expert

How did you get into a career studying rangeland ecology? What drew you to this field of study?

Whew, lots of different things. I really enjoy learning about rangeland dynamics at big, broad scales. I also like that this type of work can be used to improve things on the ground.

Dr. Allred

Dr. Brady Allred.

Why is analyzing huge datasets across time and space so important to advancing the science of rangeland ecology?

I think it is really important to “pick our heads up” and look out across the landscape. It allows us to see and understand things that we commonly miss or look past. When we combine that with the finer scale knowledge we have, we are in a really good position to do the best management and conservation we can.

What do you like to do when you’re not “out on the range?”

I just love spending time with my wife and our four children. That can be exploring Montana, helping a neighbor, running, or eating ice cream together.


You can read the original paper, “Patterns of Rangeland Productivity and Land Ownership: Implications for Conservation and Management” in Ecological Applications here.  Authors: Nathaniel P. Robinson, Brady W. Allred, David E. Naugle, Matthew O. Jones


This work was made possible by the NRCS’s Working Lands for Wildlife effort in support of sage grouse and lesser prairie-chicken conservation and the USDA’s Conservation Effects Assessment Program.

The Sage Grouse Initiative is a partnership-based, science-driven effort that uses voluntary incentives to proactively conserve America’s western rangelands, wildlife, and rural way of life. This initiative is part of Working Lands For Wildlife, which is led by USDA’s Natural Resources Conservation Service.