Map of the global environmental stratification, depicting 125 strata at a 30 arcsec (approximately 1km2) spatial resolution. The legend provides a visual combination of the three main climatic gradients incorporated in the clustering.

Global Stratification

There is growing urgency for integration and coordination of global environmental and biodiversity data required to respond to the ‘grand challenges’ our planet is facing, including climate change and biodiversity decline. On-going and new programmes are gathering valuable data through a profusion of projects at regional, national and international scales, e.g. the Long Term Ecological Research (LTER) programmes, and activities related to the Global Earth Observation System of Systems (GEOSS).

Nevertheless, great challenges remain for, among others, data aggregation across scales, consistent monitoring of global biodiversity change, and linking in situ and earth observations. Progress in these fields is essential to improve future assessments and policy targets relating to the stock and change of global ecosystem resources and biodiversity, including the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the new EU resolution to halt biodiversity loss, and the recent Aichi targets that were agreed by the Convention on Biodiversity in Nagoya in October.

A consistent stratification of land into relatively homogenous strata provides a valuable spatial framework for comparison and analysis of ecological and environmental data across large heterogeneous areas. A global stratification could provide a flexible instrument in the coordination and analysis of global biodiversity observation efforts, e.g. for targeting research and monitoring efforts, aggregating observations, and the comparison of trends within similar environments and between strata. Although there are existing global climate maps in 20-30 classes (e.g. the Köppen map), no numerical high resolution global dataset has been constructed until now that distinguished more detailed strata.

A new global environmental stratification was therefore constructed (GEnS based on statistical methods). The GEnS delineates of 125 strata, which have been aggregated into 18 global environmental zones (Figure on the right) and has a 30 arcsec resolution (0.93 x 0.93 = 0.86 km2 at the equator).

Map of the global environmental stratification, depicting 125 strata at a 30 arcsec (approximately 1km2) spatial resolution. The legend provides a visual combination of the three main climatic gradients incorporated in the clustering.
Map of the global environmental stratification, depicting 125 strata at a 30 arcsec (approximately 1km2) spatial resolution. The legend provides a visual combination of the three main climatic gradients incorporated in the clustering.

Added value of the GEnS compared to existing classifications include the rigorous statistical methods used to delineate strata, the high spatial resolution which allows for the identification of regional gradients, and the increased number of strata. Comparison with existing global continental, national stratification confirmed that it successfully partitions important environmental gradients. The dataset can therefore provide a valuable unifying framework for global biodiversity research by: supporting the aggregating and comparison of local observations; identifying gaps in current monitoring effort; targeting new monitoring and research; and supporting global assessments. The dataset will form a global unifying framework within the Group on Earth Observations Biodiversity Observation Network (GEO BON).