A Downside of Nature Conservation.
As with all conservation projects there can be downsides:
One such is an unexpected effect on green-house emissions. Researchers in Canada estimated how much the recovery of North American and Eurasian Beaver populations over the last 100 years has increased the amount of methane production, concluding that the higher numbers of Beavers now add about 800 million kilogrammes of methane annually to the atmosphere, about 15% of that from cud-chewing animals. This is a result of the recovery from hunting and reintroduction programmes, that has led to the creation of between 9,500 sq kms (and possibly as much as 42,000 sq kms) of ponded water and increased the ‘riparian interface’ by perhaps 200,000 km, both potent sources of methane. Researchers suggest these figures should be used with caution as the study makes quite a lot of assumptions.
From British Wildlife magazine, February 2015.