The omission of freshwater species from your biodiversity assessment (Nature 516, 158–161; 2014) reflects a more general bias towards terrestrial conservation, borne of insufficient knowledge about freshwater ecosystems. The Red List of the International Union for Conservation of Nature, for example, is dominated by freshwater fish species whose population status is unknown.

Integrative conservation measures are particularly important in places where people depend on freshwater resources for subsistence, and where human activities are rapidly changing rivers, lakes and their surrounding landscapes. The highly biodiverse Amazon River basin is an example. In parts of Africa, diminishing supplies of freshwater fish have led to the overexploitation of terrestrial animals (J. S. Brashares et al. Science 306, 1180–1183; 2004).

We need more data for freshwater ecosystems to inform conservation strategies and to integrate them with terrestrial habitats.