Juergen Freund / Wide angle shot of Barron Falls after a cyclone, showing increased flow of water, Wet Tropics World Heritage Area, Cape Tribulation, North Queensland, Australia. 2017.

Juergen Freund / Close-up of Barron Falls after a cyclone, showing increased flow of water, Wet Tropics World Heritage Area, Cape Tribulation, North Queensland, Australia. 2017.

SCOTLAND: The Big Picture / Atlantic salmon (Salmo salar) leaping up a small waterfall in order to reach breeding grounds further upstream, Cairngorms National Park, Scotland, UK, October.

Ingo Arndt / White water river rapids, Salto Grande, Torres del Paine NP, Patagonia, Chile

Willem Kolvoort / Tetra (Moenkhausia surinamensis) under Apinagia leaves. Awadan rapids, Gran Rio, Suriname, September.

Loic Poidevin / Grizzly bear (Ursus arctos horribilis) attempting to catch salmon leaping up rapids, Katmai National Park, Alaska, USA

Loic Poidevin / Salmon landing on head of Grizzly bear (Ursus arctos horribilis) as it is leaping up rapids, Katmai National Park, Alaska, USA

Loic Poidevin / Grizzly bear (Ursus arctos horribilis) salmon fishing in river rapids, Katmai National Park, Alaska, USA

Loic Poidevin / Grizzly bear (Ursus arctos horribilis) salmon fishing in river rapids, Katmai National Park, Alaska, USA

Will Watson / Two men crossing a cloud forest river in spate, Jama Coaque Reserve, Manabi Province, Ecuador, February 2012. No release available.

Alex Mustard / 2020VISION / Kayaker on the River Etive, Highlands, Scotland, UK, April 2012. Did you know? Freshwater ecosystems have a higher density of species than either the land or the sea.

Andy Rouse / 2020VISION / Sgwd Isaf Clun-gwyn waterfall and rapids. Ystradfellte, Brecon Beacons National Park, Wales, November 2011.