Disturbance-Dependent Species Thrive on Military Lands, According to Colorado State Study

Given the nature of the activities that occur there, military training areas are not typically considered suitable habitats for plants and animals to thrive. However, Colorado State University researcher Steve Warren has found that many species, including some threatened and endangered species, flourish on military training areas.

"Within the United States, the density of threatened and endangered species on military training areas is between 3 and 18 times greater on Department of Defense lands than on lands managed by any other federal land management agency, including the National Park Service and the U.S. Fish and Wildlife Service, whose missions include maintenance and enhancement of biodiversity. The question is why?" said Warren, director of Colorado State’s Center for Environmental Management of Military Lands.

Warren’s recent studies build on contemporary thought in the emerging field of disturbance ecology that attempts to explain how species adapt to complex and changing environments. Warren’s research contributed to the recently introduced "Heterogeneous Disturbance Hypothesis" that suggests biodiversity is maximized when multiple types, frequencies and severities of disturbance occur simultaneously on the landscape.

In one study, Warren evaluated endangered grasshoppers and tiger beetles in relation to physical soil disturbance on four active U.S. Army training areas in Germany. He and other scientists surveyed a large number of plots distributed evenly between five levels of soil disturbance in the training areas.  

The results suggest that both species are disturbance-dependent, preferring areas with significant soil disturbance during the mating season. As a result, the training areas represent some of the last remaining remnants of a habitat necessary for the survival of these species.

A second study examined two endangered toads, the natterjack toad and the yellow-bellied toad, at two U.S. Army training areas in the German state of Bavaria. Ruts created by military vehicles collect water and subsequently form ideal breeding pools for the toads. Similar to the insect study, both species of toads showed significant affinity for pools with high levels of ground disturbance, with the natterjack toad being most highly attracted to recently created pools.

While scientists do not suggest that military training is an ideal solution for preserving species, their research indicates that some species thrive in highly disturbed environments. The results provide educational information about the ecological phenomena that occur on military training areas and suggest that efforts to restore and maintain biodiversity on the landscape must include a disturbance regime that creates and maintains a heterogeneous habitat.  

The European Union’s Habitat Directive mandates that all nations within the European Union designate a percentage of their landmass as special areas of conservation to be included in the Natura 2000 network. The legislation is designed to protect the most seriously threatened habitats and species across Europe. Noting the high biodiversity on their training areas, many nations in the European Union have designated large percentages of their military training areas.  

The U.S. Army maintains training areas in several European countries, and 77 percent of those training areas have been nominated by the host nations to the Natura 2000 network.