We are in a period of global warming that effects not only temperatures but rainfall and wind patterns too. Some animals can migrate to avoid the changing conditions and plants will change their distribution over time even though individuals are rooted in one spot. The changes attributed to climate change can be divided into two categories, 'changing distribution of species' and 'altered development and life cycles'.
Changing distribution of species
Changing communities and alien invaders
Climate change will cause the balance of species within a community to shift. Some species may benefit from the new conditions may become dominant while others may be lost from the community all together due to competition with existing or invading species. If they are mobile or have good seed dispersal they may be able to move to more favourable conditions, the distribution of some species will change. For example, plants found mostly in northern England and southern Scotland such as ground thistle may move to the north whereas others such as heath bedstraw may move south. Future communities may be quite different from those today. The speckled wood butterfly has moved north in Britain. The change in distribution may be a direct response to the raising temperature or a result of a shift in distribution of the plants they feed on. In addition to this the higher temperatures earlier in the year could increase the growing seasons and frost sensitive plants such as olive and citrus plants could be grown much further north. Butterflies and plants whose seeds are carried by the wind are easily able to disperse over long distances to find a more suitable habitat however many animals and plants lack this skill/feature. As so much of the environment is now used for agriculture or is used for building it is becoming less likely that organisms will be able to move to a more suitable place and will therefore die out.
Another problem for some communities could be the introduction of an exotic or alien species from another region of the world which could push out other inhabitants. Pests and diseases may also spread to new areas and act to reduce crop yields. Witchweed is a parasitic weed which infects cereal crops in Africa. It taps directly into the host plant and absorbs its nutrients and moisture and as a result the host plant is less productive and destroying 30-100% of the crops. If global temperatures increase the witchweed…