The Impact of Climate Change on Wildlife and Habitats
In this pod, we’ll discuss the effects of climate
change on wildlife and habitats.
We’ve always had climatic fluctuations and the world’s
plants and animals have always had to deal with them. So, why do we need to
worry about the impact of climate change on wildlife and habitats now? The
answer is a simple one – speed. The rate at which climate change is happening
is unprecedented. Previous changes took place over millennia and species had
time to migrate and adapt. The concern is that we no longer have the luxury of
time. This will result in species and habitat losses on previously unseen
Change is already happening. Evidence suggests
that warming over the last century has already led to ecological changes. This includes changes in the length of
growing seasons, changes in the locations of where species grow and breeding
patterns. The future existence of the
species we know today will depend upon their ability to move from areas where
the climate is no longer favourable. This is clearly much easier for animals
than plants. From the Darwinian ‘survival of the fittest’, we may now witness
the ‘survival of the fastest.’
World Wildlife Fund scientists have calculated
that plants and animals will have to move more than 1000 metres polewards per
year if they need to stay in their current climate zone. This is certainly a long way!
The British comma butterfly has moved 220
kilometres northwards in the last 20 years and moths on Mount Kinabalu in
Borneo have shifted 59 metres uphill in 45 years.
But what if you’re a polar bear? You can’t move any further north. Polar bears and snow leopards literally have
nowhere left to go. Around Norway’s polar islands, scientists have found many
more warm water crustaceans. The snow crab is regularly being found 500 kilometres
further north than previously.
Seasonal changes are trigger points for important
stages in the life cycle of plants and animals, such as in mating, reproducing
and migrating. Scientists have noticed a
phenomenon that they call ‘spring advancement.’
This is the earlier arrival of breeding seasons and migration, as well as
of plants coming into bud and flowering. For example, birds such as the song
thrush are arriving in England earlier than before and edible dormice are
coming out of winter hibernation, on average, 8 days earlier.
How does spring advancement affect the ecosystem?
Well, let’s take the mountain pygmy possum of Australia as an example. It is emerging from hibernation before its
prey. As a result, many die of starvation. In the past two decades, there have
been more than 160 species extinctions due to climate change. These have happened mainly in Central
America. For example, the golden toad and the Monteverde harlequin frog are no
longer with us.
Plants are being affected too. The Haleakala silversword
is only found on one Hawaiian mountain top. But shifting weather patterns have
made the mountain too dry and too warm for new seedlings to grow. The older
plants are dying off but not being replaced.
The forests of North America are being attacked by beetles who are now
able to survive much further north due to warming temperatures. This has happened near Radium Hot Springs in
Canada, where the pine trees have been killed by pine beetles. Large areas of forest in Australia, Russia
and France are losing trees, either through drought or high temperatures.
The Asian tiger mosquito is now found in several
southern European countries and is likely to travel further north. When species travel out of their climate zone
they cause problems, as they have to find a new food source. We refer to these
migratory animals as invasive species. Examples
include the European green crab and the Japanese ghost shrimp, who are moving
further north and disrupting the food chain in their new locations.
It’s not just individual plant and animal species
that will be affected by climate change. On a larger scale, whole biomes will
be affected. Remember, a biome is a large community of plants and animals that
share an environment and climate. It’s the northern latitudes that are being
most affected. Climatologists predict that the northern coniferous forests will
eventually occupy the area that is now the frozen tundra. They also say that
the hot desert areas will become much larger, with the savanna areas extending
into the current Mediterranean biome.
As things shift northwards, the UK may well
become more like southern Spain – great if you want a holiday, but not so good
for water supply and agriculture.