Biota and Climate

The word biota is a collective term, simply meaning “living organisms.” Strictly speaking this includes human beings, but here the focus is on nonhuman living things. Climate can be defined as the average weather conditions of a place, determined over a long enough period of time to ensure that the full range of conditions normally experienced is taken into account, while unusual conditions happening within the measurement period do not unduly influence the average. Climate is therefore commonly calculated from weather conditions over a period of 20 to 50 years and includes temperature, precipitation, daylight, and wind, among other variables. Biogeography focuses directly on the study of patterns of life in both space and time. The biotic environment is an important part of “the environment” more generally, which is the central element of physical geography. Both present and past climate affect which organisms can live in a place, but the strength of this influence varies depending on the type of organism and the medium in which it lives (land or water).

The study of the present climate's influence on organisms is a strong focus of what is often called “environmental biogeography,” while the influences of past climate—in tandem with the movement of tectonic plates—are a major focus of “historical biogeography.” Increasingly, the distinction between these two subdisciplines of biogeography is breaking down, as it seems clear that a good explanation of patterns of life in the world today requires elements of both. Furthermore, it is increasingly appreciated that, as well as being strongly affected by climate, living organisms can affect climate and therefore climate change at all spatial scales. Clearly, relationships between biota and climate are a very important part of geography. Below, a fuller consideration of how climate affects biota is followed by discussion of the how living organisms affect climate and the feedbacks between the two, using the relationship between climate and species richness as an example. The entry concludes with an overview of current research directions and priorities in the field more generally.