Conservation of the Earth’s biodiversity is essential for human existence at three levels: ecosystems, species and populations. Populations, not species, are recognized as the appropriate scale for the management of sustainable harvesting and protection in endangered species legislation. Nevertheless, population diversity – the number, distribution and differentiation of populations within different species and ecosystems – is typically ignored in most biodiversity syntheses and large-scale conservation planning. Accurate data and modelling of population diversity are required to inform management decisions that will have far-reaching consequences for biodiversity stewardship and environmental sustainability.

In this light, we are taking a macroecological perspective to: (i) determine how many populations exist within different species and ecosystems across the Americas; (ii) relate how many populations are found within a certain area (km2) and to contrast this with how many species reside in the same area, and (iii) project future population loss associated with different human activities across ecosystems (e.g. urbanization, deforestation, land conversion, mining, etc.). Through these objectives, we will reveal as yet unrecognized global population diversity patterns and consequences of human-induced changes to population biodiversity, and highlight key regions for focusing future conservation priorities that encompass all three biodiversity levels.