By Steve Head Reviewed by Andrew Salisbury This is a very important topic. While there is a consensus that human induced climate change is
happening, its predicted effects on UK weather are full of uncertainties. The UK’s climate and weather patterns will change and appear
already to be changing. We are commissioning a full review of how climate change could affect garden wildlife, this temporary
page sets out some basic information pointers.
By Steve Head Reviewed by Andrew Salisbury
This is a very important topic. While there is a consensus that human induced climate change is happening, its predicted effects on UK weather are full of uncertainties. The UK’s climate and weather patterns will change and appear already to be changing. We are commissioning a full review of how climate change could affect garden wildlife, this temporary page sets out some basic information pointers.
Changes already visible
Flowering has become up to 13 days earlier, because of warmer springs, but reduction in winter chill has delayed the flowering of some plant species which need a cold snap to trigger flowering. Extreme weather events, like the 1976 drought which killed sycamore and beech, showed how climates change could affect trees.
Spawning and hatching are happening earlier in frogs, now even before Christmas in the south-west. Overall frog and toad populations have declined, consistent with low summer rainfall in the period 2003-2006 (before recent red-leg disease) - alongside habitat loss.
In the UK a wide-range of species have shifted their distributions northwards at the rate of some 10 - 25 km every decade. The garden tiger moth is now uncommon in the south, but continues to survive in the north, apparently in response to warmer winters. Current warming probably contributed to the spread of bluetongue virus in UK sheep and cattle, as its biting midge vector is spreading north in Europe. Migratory insects are arriving with increasing frequency and new species, such as the tree bumblebee, are now resident in the UK, possibly associated with climate change.
Likely future effects on wildlife
The trends already visible will continue and become more prominent. The best current review of likely effects on wildlife is the Terrestrial Biodiversity Climate Change Impacts Report Card 2012 -13, and the bulleted list below is based largely on this.
Climate change impacts on gardens
Gardeners will feel both positive and negative effects of climate change. Reading University has produced a review “Gardening in the Global Greenhouse” which comes up with several broad conclusions:
Gardens and conservation in a changed world
Gardens may have some important conservation roles under climate change. They will be better maintained, in terms of protection from gales and drought, than the countryside and nature reserves, and their role in sustaining generalist species may become even greater. Locally therefore, they will have a mitigating role for wildlife as well as people.
The enormous numbers of gardens, and the short distances between them, mean that they could become extremely significant stepping stones, or even corridors, for mobile species adapting by dispersing towards favourable habitat. Gardens already contain a very large number of non-native Western Palaearctic plant species, and some of these may become significant as food plants for continental insect species migrating with the changed climatic conditions.
There remains a concern that some species only currently surviving in gardens through winter protection, could become viable in the countryside, and a small fraction of these could become invasive. Given however, that the whole pattern of species and communities in Britain will be deeply impacted, it is possible that some of these newly acclimitised species may have positive outcomes for the biodiversity of Britain in the future.