Climate and plant distribution

The central thesis for plant ecology is that climate exerts the dominant control on the distribution of the major vegetation types of the world. Within a vegetation type smaller-scale variations in distribution may be controlled by smaller-scale features of the environment such as soil types, human activity or topography. However, at all spatial scales the response of the plant to climate is a crucial feature in its presence. In view of the importance of climate in controlling distribution of plants it is surprising that this area of subject is not a popular one in plant ecology. Such questions as 'when' and 'how' does climate have its effect are clearly difficultl to answer, perhaps explaining the limited acceptance as an area of study. I have set out to encourage an interest in climate and plant distribution by proposing different approaches to the subject. They are approaches which many not find general acceptance, but if they create interest and debate, which is my hope, then they will have been successful. I have drawn exclusively on vascular plants as examples of distribution types and responses. This reflects my interests and is not a comment on the ecology of non-vascular plants. Where possible, I have also avoided the use of the emotive terminologies, such as niche, strategy and adaptation; however I admit to the unavoidable use of competition, in spite of real problems in its measurements.