Natural freshwater ecosystems represent the terrestrial phases of the global hydrological cycle and include rivers, streams, lakes, ponds, wetlands as well as groundwaters. While fresh waters comprise only 0.01% of the water on Earth and constitute less than one-tenth of the global land surface area, they support > 10% of all recorded species including ∼ 30% of all vertebrates. Freshwater ecosystems support the provision of numerous ecosystem services which are being jeopardized by a multitude of anthropogenic stressors such as climate change and invasive species, among many others. Fortunately, many options for freshwater ecosystem conservation exist and must be acted upon immediately.