Botanic Gardens Conservation International
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Climate change and plants

Historical climate change has had a profound effect on current biogeography, so we can expect our ongoing and rapid climate change, to have as great an effect. Climate change has important implications for nearly every aspect of life on Earth, and effects are already being felt.

  • Temperature effects–average, minimum or maximum can be important determinants of plant distribution
    For example the Palmae/Arecaceae are cold intolerant as their single meristem is susceptible to frost.
    Conversely, boundaries between vegetation types (e.g. Arctic treeline) are generally determined by summer warmth
  • Rainfall is also an important determinant: for example it affects the balance of grasses to woody vegetation
  • Other factors such as soil type or herbivory may also be affected by climate change.

Effects on Plant Diversity

  • Species ‘left behind’ as they are unable to change distribution fast enough.
    Species with long life cycles and/or slow dispersal are particularly vulnerable.
  • Some isolated or disjunct species are particularly vulnerable, as they may have 'nowhere to go'. These include
    Arctic and alpine species, and Island endemics
    Coastal species
    which will be 'squeezed' between human settlements and rising sea levels.
  • Plant genetic composition may change in response to the selection pressure of climate change.
  • Some plant communities or species associations may be lost as species move and adapt at different rates.
  • Increased invasions by alien species may occur, as conditions become more suitable for exotic species whilst native species become less well suited to their environment (for example, Bromus is more invasive in wet years (Smith et al, 2000)). This is especially true given human interventions which have deliberately and accidentally facilitated the spread of species across the globe.
  • Many plant communities act as 'sinks' (store carbon), which helps to offset carbon emissions. However, over the next 70 years, the effects of climate change on plants mean many terrestrial sinks may become sources.