The cold, hostile conditions found on
mountains have forced plants and animals to adapt and change they
way they find and store food. Organisms in this environment have to
cope with thinner air, lower temperatures, a shorter growing
seasons and infertile soils. These include the Swiss Alps in Europe
the Australian Alps, the Himalyas in East Asia, the Rockies in
North America and Andes in South America. Animals need to keep
their body temperature higher than their surroundings so they need
more energy to survive. The high winds, snow and extreme
temperatures mean that food is hard to find, forcing both plants
and animals to find more efficient ways of gaining energy.
Food webs in alpine regions are simple and fragile
compared to food webs found in other conditions. There are fewer
carnivores, herbivores and primary producers so a delicate balance
is needed to allow all organisms to survive.
Plants in alpine regions need to retain as much
available heat from the environment as possible, this reduces the
amount of energy they need to keep their temperature constant.
Their leaves are a deep, dark green as darker colours absorb and
retain more heat. The plants will often be hairy and lie low to the
ground to reduce the amount of heat lost. Many alpine plants have
adapted so that they can grow and even produce flowers at very low
temperatures. The cells are smaller than normal plant cells and
contain high concentrations of solutes which protect the cell from
freezing in the cold conditions, acting like antifreeze in car
engines. Some plants can actually produce enough heat to melt the
surrounding snow.
Very few animals are able to live in alpine regions
as there is little food or water available. Water is frozen as snow
and few plants grow, those which do are usually small. Animals need
to change the ways in which they find and use food to survive in
these conditions. In winter few animals are able to find enough
food to meet their energy needs so they must migrate, hibernate or
take shelter under or above the snow until summer. Larger animals
such as the bighorn sheep and elk are able to conserve their energy
because of their fat and fur. They usually move down slope during
the colder months where there is more food available and return in
spring. The ground squirrel hibernates over the winter period and
adjusts its eating habits to provide enough energy during this
time. During summer it feeds on nuts and berries in large amounts,
providing excess energy which is stored as fat. It then builds a
grass or fur lined burrow and maintains a body temperature of 8-10
degrees C (46-50 degrees F). Its metabolism drops dramatically and
the stored energy is consumed slowly.
The meadow vole alters its feeding habits, spending
its winter under the snow where it is able to find enough food and
water to survive. The rocky mountain goat has developed a highly
efficient digestive system which is able to extract almost all of
the stored energy from plants. During the winter months it is able
to eat fewer plants but still gain the energy it needs.
Some animals are able to live at high altitudes,
forming a small but efficient food chain. The organisms found to be
living at the highest point is the jumping spider, living at 6 700m
(22 000 ft) on Mt Everest. They eat small flies and springtails,
which gain energy from fungi and rotting vegetation.
