Climate change affects bees

Climate change has negative effect on bees

Smart Farmer How To
HARMFUL: Extreme heat has a very negative effect on bee colonies, making flower seasons shorter and erratic. Photo: Denis Howard.

HARMFUL: Extreme heat has a very negative effect on bee colonies, making flower seasons shorter and erratic. Photo: Denis Howard.

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We hear so much about climate change and its implications for our lives and lifestyle, but what about bees?

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We hear so much about climate change and its implications for our lives and lifestyle, but what about bees?

This question was addressed at a Hunter Valley Amateur Beekeepers' Tocal Field Day some years ago by Des Cannon, former professional beekeeper and (then) editor of The Australasian Beekeeper.

Bees have survived many episodes of change in the millions of years they have been on earth, but current focus is on the problems of increased atmospheric carbon dioxide and global warming with rising ocean temperatures, rising average land temperatures, episodes of extreme heat, bushfires and decreased rainfall.

There is evidence of change in the seasonal pattern of bee diseases such as chalk brood, a fungal infection of brood.

This is more evident in autumn and beekeepers must take steps to ensure affected colonies have the strength to survive winter.

The small hive beetle, a menace to beekeepers since its arrival in 2002 loves warmth and humidity so it is most active and destructive in long hot summers.

Its relentless spread southwards is aided by increased summer heat.

Extreme heat alters the bees' foraging pattern:

  • Greater than 37 degrees Celsius - field bees switch from foraging for nectar to collect water to cool their hives;
  • Greater than 43C - all collecting water; and
  • Greater than 47C - wax softens and cannot support the weight of honey resulting in a big mess in the hive.

Flowering seasons are shorter and more erratic as hot days disrupt blooming and decrease availability of pollen.

Nectar becomes decreased in amount, concentrated and thick.

The protein content of pollen is degraded, rendering it inadequate to satisfy the nutritional needs of bees.

While bees can be very skilled at maintaining the temperature within the hive at around 35C they need shady sites in summer, sunny in winter.

We don't have many deciduous trees in Australia, making this difficult, but the use of shade cloth helps.

Attention to choice of hive construction to ensure adequate air circulation within the hive demands a knowledge of current views and practices.

Water availability is essential. Regulations in some states make it mandatory for beekeepers to supply water close to apiaries.

With apiaries bees in a bush setting, care must be taken to ensure safety from bush fires with a clear mown area around hives.

Contending with climate change is just one more challenge for beekeepers, professional and amateur.

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