Consequences of Climate Change

Changing Distribution of Species
1. Climate change will cause the balance between species in the community to shift.
2. Some species will benefit from the change in conditions and become dominant.
  1. Other species may be lost from the community due to competition with existing or invading species.
3. Distrobution of some species is likely to change.
  1. They might migrate to more favourable conditions if they have good seed dispersal or if they are mobile.
  2. For example, as the moment ground thistle in Scotland has reached its northern limit but in the future they will begin to expand northwards.
4. Due to global warming temperatures are higher earlier in the year.
  1. This could extend the growing season for crops.
  2. Crops such as olives and citrus plants that are sensitive to frosts could be grown further north.
5. Pests and diseases may also spread to new areas and act to reduce crop yields
  1. Witchweed is a parasitic weed that infect cereal crops.
    1. It requires a temperature of at least 28oc to grow effectively.
      1. If global temperatures increase, it may spread to cereal crops in new areas and cause even more damage.
    2. Most weeds simply compete with crops.
      1. A parasitic crop such as witchweed, will tap directly into its host plant and absorbs nutrients and moisture.
        The host plant is less productive as a result.
        Thus destroying 30-100% of the crop.
6. Its not only changing temperature that affects species distribution.
  1. There are other factors that are likely to influence species and communities.
    1. Changing rainfall patterns
    2. Soil moisture
    3. Winds
    4. Rising sea levels
Altered Development and Life Cycles
1. Faster Photosynthisis
  1. Therefore faster growth.
    1. A few degrees of warming will lead to an increase in temperate crop yields
      1. However a greater temperature rise could reduce crop yields
  2. The rate of photosynthesis is determined by by a number of limiting factors
    1. Carbon Dioxide concentration
    2. Temperature
      1. In cooler climates
        Temperature is a limiting factor
        A rise in temperature would result in faster rate of photosynthesis.
        Above an optimum temperature, plant enzymes work at a very slow rate.
        Optimum temperature varies in different species.
      2. Tropics
        Many crops in the tropics are at the limit of their temperature tolerance.
        Therefore a small rise in temperature would be likely to decrease the yield.
        Direct effect of temperature rise
        Resulting fall in soil moisture
2. Animals will be affected if temperature acts as an environmental cue or trigger for their development or behaviour.
  1. Salmonoid fish: hatching and growth rates are most likely to be affected.
    1. Research shows that brown trout stop growing in late summer when the river temperatures have heated up.
      1. Currently this is not a problem as they have already completed most of their growth by late summer.
        However if river temperatures were to warm up earlier
        The trout might stop growing earlier
        Resulting in underweight fish with reduced chance of surviving the winter
  2. The sex of some reptile offspring is determined my the egg incubation temperature
    1. In leatherback turtles, higher temperatures in the nest result in females
      1. If temperature increases
        Cooler nests producing males will become less and less common
        This would threaten the survival of the species

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Consequences of Climate Change

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	Created by goosepuckett over 10 years ago