Scat-Loving Snakes

Many farmers have stopped keeping manure heaps on their land, and snakes that rely on these piles of dung for nesting sites could suffer, scientists report in Biodiversity and Conservation.

Some reptile species in Europe are declining, but devising conservation strategies is challenging because scientists often know little about the animals’ lifestyles. One species that may be at risk is the grass snake (Natrix natrix). In cold parts of Europe, grass snakes often seek out warm places to store their eggs, such as compost and manure heaps on farms. But some farmers are getting rid of these piles or putting them in enclosures that snakes can’t access.

To find out if the snakes could nest in other places, the team studied grass snakes in Sweden. The researchers moved 252 snake eggs to compost piles, manure heaps, or alternative natural nest sites in rotting logs and plants.

The manure heaps offered the coziest spot for the eggs, with an average temperature of 26 degrees Celsius. The compost piles and natural nests were cooler at 23 degrees and 17.7 degrees, respectively. Almost three-quarters of the eggs in the manure heaps hatched successfully, while only 43 percent of those in compost piles and none of the eggs in natural nests did.

The disappearance of manure heaps and compost piles “is therefore a threat to grass snakes because there are few if any natural environments in which their eggs can develop successfully,” the authors write. Bringing back manure could help other species such as European rhinoceros beetles as well, they say. Roberta Kwok | 26 June 2012

Source: Lowenborg, K. et al. 2012. Agricultural by-products provide critical habitat components for cold-climate populations of an oviparous snake (Natrix natrix). Biodiversity and Conservation doi: 10.1007/s10531-012-0308-0.

Image © Andyworks | iStockPhoto.com

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