Explosions in military training sites can actually provide habitats for some species.© Punchstock

Military exercises are boosting biodiversity, according to a study of land used for US training manoeuvres in Germany. Such land has more endangered species than nearby national parks.

The land is uncultivated, but also churned up by tank tracks and explosions. This creates habitat both for species that prefer pristine lands and those that require disturbed ground, explains ecologist Steven Warren of Colorado State University in Fort Collins.

Military land can host more species than agricultural land, Warren told a meeting of the Ecological Society of America in Montreal. What's more, its biodiversity can also exceed that of natural parks, where species that need disturbance cannot get a foothold.

Warren and his colleague Reiner Büttner of the Institute of Botany and Landscape Ecology in Hemhofen, Germany, surveyed two US military bases at Grafenwoehr and Hohenfels in the southern state of Bavaria. Although the bases represent less than 1% of the state's area, they contain 22% of its endangered species, Warren told the meeting. The national parks cover a similar area but host fewer endangered plants and animals, Warren says.

Nature's army

"Some people are very anti-military," Warren says. "They assume that there's nothing the military can do that will be beneficial, particularly with relation to ecology." Warren, who doesn't work for the army, used to assume the same himself. "Twenty years ago I looked at military activities as an ecologist and thought 'they need me'. But I guess that's not really so."

Warren and Büttner studied several species to try and understand the benefits of military ground. One, the natterjack toad, breeds in water-filled ruts created by tank tracks, they found.

The tendency when setting aside a nature reserve is to prevent disturbances such as periodic flooding, says Warren. But this can inadvertently remove some habitats.

"[Tanks] replace to some degree the processes that have been stopped," Warren says. The same goes for fires caused by bombing. "We've trained generations of people that fire is bad," he says, "but in fact it's crucial for ecosystems."

Trial by fire

The number of species on former Soviet training camps around Berlin has dropped since the fall of the Iron Curtain, Warren says, supporting the idea that military activity is good for biodiversity.

"But some military chiefs worry that endangered species may begin to obstruct their exercises." The US Marine Corps has previously complained that the US Endangered Species Act threatens to turn its Camp Pendleton beach in San Diego County, California - home to 18 threatened species - into a nature reserve rather than a training facility.

Warren hopes that conservationists could learn from the military, and provide disturbances to help endangered species. One trial project at Tennenlohe, near Nuremberg in Germany, involves cutting up land using an agricultural tool called a ripper in a bid to mimic tank tracks.