The Lesser Prairie Chicken says rangelands aren’t as healthy as we thought
Submitted by joel brown on Mon, 03/31/2014 - 14:55
The U.S. Fish and Wildlife Service just proposed to list as ‘threatened’ the Lesser Prairie Chicken throughout much of the high plains region based on a precipitous decline over the past 10-15 years. This shouldn’t have happened. Rangeland management has been based on the idea that if we manage a particular piece of land, or a ranch, or a landscape correctly, then we should expect more stable production of livestock products, water yield, and wildlife. Proper rangeland management produces resilience--the ability to withstand the vagaries of climate and still yield a fairly consistent income. We have been pretty good at this; rangeland management has improved vegetation cover on rangelands throughout most of the U.S., certainly not to the point that we would like, but progress nonetheless. However, even as those indicators of ‘health’ have continued to improve, we have seen new problems emerge.
When we look at the indicators of rangeland health in the historic range of the prairie chicken (plant species composition, amount of rangeland acreage, soil health, etc.) we generally see stable to slightly upward trends for the past 20-30 years. So, why is a species dependent on rangeland in decline while our measures of rangeland health indicate improvements? Well, there is always the possibility that our measurements, of either bird numbers or rangeland health, are wrong. Or, dramatic changes in the amounts of rangeland that occurred in the past are just now having an effect on population numbers.
The other, very strong possibility is that something else is going on and is responsible for the instability in lesser prairie chicken numbers. In the FWS press release on the listing proposal, they listed road building for energy exploration, wind turbine tower construction and oil and gas drilling rigs, in addition to habitat loss to agriculture as the reasons for population decline. Agencies and land owners have been proactive in managing to improve habitat, including preserving open land and converting marginal cropland to perennial grasses. But, a critical question would have to be: can large scale land management efforts (like grassland restoration or rangeland improvement) overwhelm the negative effects of widely distributed small-scale disturbances (like roads, power lines and wind towers)? Or in the context of one of Brandon’s earlier posts: are the positive feedbacks (instability) associated with energy development outweighing the negative feedbacks (stability) associated with conservation via land use and management?
While we can use tools such as soil survey, ecological sites, remote sensing, GIS, population models and many yet to be developed, a very difficult problem remains; how do we examine and communicate to people about how entire land mosaics are changing, what we can do about it, and most important, how do we logically make those decisions given that they involve such large expanses of land and so many competing interests? We’ve done a pretty good job of developing tools that can tell us about the quality of a small, isolated piece of land, but we’re not particularly good about the landscape and regional context that determine how prairie chicken populations function within the ecosystem.
We have some theory to guide our thinking. In 1985, the book The Ecology of Natural Disturbance and Patch Dynamics by Steward Pickett and Peter White illustrated how fairly dramatic changes in comparatively small patches could affect stability in larger scale processes. The idea that stability, and sustainability, at larger scales depended on change in the qualities and arrangement of smaller subunits, is really interesting as a theory, but poses some challenges for managers and policymakers. It means that in spite of our best efforts to improve the health one piece of ground, or to incentivize improvements across a broad land area, land uses in certain areas--that are outside of our immediate control--may thwart our goals. It’s a well understood theoretical problem in landscape ecology, but that doesn’t mean we are any closer to using the ideas in designing land management strategies. Maybe the prairie chicken can tell us how.