Climate change causing a slug population boom

The combined effects of a relatively warm winter and wet summer in 2015 as well as a chronic decline in the populations of some amphibians and hedgehogs have potentially triggered a huge increase in slugs in Britain.

According to Countryfile, while snails hibernate in winter, slugs are capable of sustaining activity in temperatures above 5ᵒC. Considering the uncharacteristically warm winter months of 2015-16, during which a record-high average temperature of 7.9ᵒC was measured, slugs have been able to feed and reproduce for longer periods than usual, precipitating a population boom. Wetter summers have also helped facilitate a burst in slug activity, effectively creating year-long favourable conditions for slugs.

The changing ecological landscape of Britain has not helped matters as declining populations of frogs and hedgehogs, both predators of slugs, has eased the pressure of interspecific interactions on these garden pests.

These factors, operating in tandem, are resulting in a “generation of sleepless slugs”, with estimated population increases of more than 10%. Additionally, various slug varieties have been observed to grow at faster-than-normal rates, reaching “full size” earlier than usual. British gardens this summer must therefore contend with a larger number of more active, faster growing slugs than in previous years, likely to cause a great deal of devastation through their consumption of various fresh leaves. The Royal Horticultural Society has subsequently recommended a variety of measures to keep the pests at bay, including the application of nematode worms—which kill slugs by infecting them with disease-causing bacteria—as well as the use of barriers to protect particularly vulnerable plants.

This phenomenon points to the often dramatic consequences that a combination of climatic and ecological influences can have on different species, something that is likely to grow in prominence with the ongoing effects of climate change and a declining global biodiversity.

Image Credit: Countryfile