Terrestrial biomes: a conceptual review

Aims: We attempt to review the conceptualisation, science and classification of biomes and propose to limit the definition of a biome to potential natural vegetation as determined by general environmental variables. Results: Classifying the distribution and abundance of vegetation types on earth has been a central tenet of vegetation science since Humboldt’s classic studies in the early 1800s. While the importance of such classifications only grows in the wake of extreme changes, this review demonstrates that there are many fundamentally different approaches to define biomes, hitherto with limited efforts for unifying concepts among disciplines. Consequently, there is little congruence between the resulting maps, and widely used biome maps fail to delimit areas with consistent climate profiles. Conclusions: Gaps of knowledge are directly related to research avenues, and suggestions for defining and classifying biomes, as well as modelling their distributions, are provided. These suggestions highlight the primary importance of the climate, argue against using anthropogenic drivers to define biomes and stabilize the concept of biome to escape from the current polysemy. The last two decades have seen an emergence of new approaches, e.g., using satellite imagery to determine growth patterns of vegetation, leading to defining biomes based on the objective, observable qualities of the vegetation based on current reality.