A global test of ecoregions

Area of Science:

• Ecology
• Biogeography
• Conservation Biology

Background:

• The concept of distinct ecoregions and biomes shaping species assemblages is fundamental to biological and Earth sciences.
• This paradigm has historically guided scientific inquiry and environmental policy.
• Recent technological advancements enable re-evaluation of whether ecoregions truly delimit biological communities.

Purpose of the Study:

• To test whether terrestrial ecoregions meaningfully delineate biological communities.
• To compare the sharp-transition hypothesis against the gradual-transition hypothesis using extensive biodiversity data.

Main Methods:

• Utilized over 200 million observations of plants, animals, and fungi.
• Tested two hypotheses: sharp-transition (borders divide distinct communities) vs. gradual-transition (turnover is continuous).
• Analyzed species turnover patterns in relation to ecoregion boundaries across different taxa.

Main Results:

• Found strong evidence supporting the sharp-transition hypothesis across all studied taxa.
• Observed that plants and vertebrates show strong adherence to ecoregion boundaries.
• Noted weaker affiliations of arthropods and fungi to the defined ecoregion borders.

Conclusions:

• Ecoregions are validated as significant delineators of terrestrial biodiversity patterns.
• Ecoregion-based conservation planning is crucial for protecting species, communities, and ecosystems.
• Protecting habitats across multiple ecoregions is essential for safeguarding Earth's life support systems.