The IUCN classification of global ecosystems was released in 2020: https://global-ecosystems.org/
There’s a neat interactive map to explore. With things like this, I’m always curious if iNaturalist observations of species will ever help define the finer, more local ecosystem and habitat classifications (which is explicitly outside the scope of this global effort, see more explanation below).
The new IUCN Global Ecosystem Typology is a comprehensive classification framework for Earth’s ecosystems that integrates their functional and compositional features. This new typology will help identify the ecosystems that are most critical for biodiversity conservation, research, management and human wellbeing into the future.
The IUCN Global Ecosystem Typology comprises six hierarchical levels, with the three upper levels developed on this website, allowing navigation from global to local scales. The three upper levels – realms, functional biomes and ecosystem functional groups – classify ecosystems based on their functional characteristics (such as structural roles of foundation species, water regime, climatic regime or food web structure), rather than based on which species live in them.
The three lower levels of classification – biogeographic ecotypes, global ecosystem types and subglobal ecosystem types – are often already in use and incorporated into policy infrastructure at national levels and can be linked to these upper levels. This is crucial, as important conservation action occurs at local levels, where most ecosystem-specific knowledge and data reside.
- Realm: One of five major components of the biosphere that differ fundamentally in ecosystem organisation and function: terrestrial, freshwater, marine, subterranean, atmospheric and combinations of these (transitional realms). Because variation in nature is continuous, we also include transitional realms, where the realms meet and have their own unique organisation and function.
- Biome: A component of a realm united by broad features of ecosystem structure and one or a few common major ecological drivers that regulate major ecological functions, derived from the top-down by subdivision of realms (level 1).
- Ecosystem Functional Group: A group of related ecosystems within a biome that share common ecological drivers, which in turn promote similar biotic traits that characterise the group. Derived from the top-down by subdivision of biomes.
Lower levels (4-6) beyond the scope of this website:
These three levels are often already established classifications, sometimes organised as a sub-hierarchy of multiple levels, derived directly from ground observations.
Biogeographic ecotypes (level 4) are ecoregional expressions of an ecosystem functional group (level 3). They are proxies for compositionally distinctive geographic variants that occupy different areas within the global distribution of a functional group. Global ecosystem types (level 5) are complexes of organisms, with similar ecological processes and their associated physical environment within an area occupied by an ecosystem functional group, but with substantial difference in composition of organisms. They are derived from the bottom-up (national or regional), either directly from ground observations or by aggregating the lowest level, the Subglobal ecosystem types (level 6). These are subunits or nested groups of subunits within a global ecosystem type, with more compositional resemblance to one another, than other global ecosystem types.