Steven Kazlowski,Steven Kazlowski / Polar bear (Ursus maritimus) juvenile spreading body weight over thin newly forming pack ice, trying not to break through, Beaufort Sea, off the 1002 area of the Arctic National Wildlife Refuge, North...

Steven Kazlowski,Steven Kazlowski / Polar bear (Ursus maritimus) juvenile rolling around on newly formed pack ice, Beaufort Sea, off the 1002 area of the Arctic National Wildlife Refuge, North Slope, Alaska

Steven Kazlowski,Steven Kazlowski / Polar bear (Ursus maritimus) portrait, female. Bernard Spit, 1002 area of the Arctic National Wildlife Refuge, North Slope, Alaska.

Steven Kazlowski,Steven Kazlowski / Polar bear (Ursus maritimus) curious adult head underwater, Beaufort Sea, off the 1002 area of the Arctic National Wildlife Refuge, North Slope, Alaska.

Steven Kazlowski,Steven Kazlowski / Polar bear (Ursus maritimus) young bear in freezing water during autumn freeze up, Bernard Spit, 1002 area of the Arctic National Wildlife Refuge, North Slope, Alaska, Beaufort Sea

Steven Kazlowski,Steven Kazlowski / Polar bear (Ursus maritimus) 4-5 year-old on pack ice, low angle shot, off the 1002 area of the Arctic National Wildlife Refuge, North Slope of the Brooks Range, Alaska, Beaufort Sea, autumn

David Woodfall / Bird hide, created by Birdwatch Ireland to study and monitor Little tern (Sterna albifrons) colony, indicator species of climate change. County Wicklow, Republic of Ireland. June.

David Woodfall / Two little tern (Sterna albifrons), one with sand eel landing at the nest amongst Black Oats growing on shell rich sands Machair , Indicator bird of climate change because of its dependence on sand ee...

David Woodfall / Little tern (Sterna albifrons ) with newly hatched chick, feeding sand eel-Hyperoplus spp.Indicator of climate change as Little terns are only able to feed in top layer of sea water , and as sea warms...

Andy Sands / Oxlips (Primula eliator) flowering in coppice woodland, a rare and important ancient woodland indicator species, Suffolk, England, UK, April

Andy Sands / Herb paris (Paris quadrifolia) Plant growing among other woodland plants indicator species of ancient woodland, Suffolk, England, UK, May

Andy Sands / Herb paris (Paris quadrifolia) Close up of flower from the side - indicator species of ancient woodland, Suffolk, England, UK, May, Focus Stacked

Andy Sands / Herb paris (Paris quadrifolia) Plant growing in coppice woodland indicator species of ancient woodland, Suffolk, England, UK, May, Focus Stacked

Andy Sands / Downy birch (Betula pubescens) left standing among 2nd year coppice re-growth, an ancient woodland indicator species in UK, Suffolk, England, UK, May

Andy Sands / Hornbeam tree (Carpinus betulus) ancient pollard growing in mixed woodland - good ancient woodland indicator, Essex, England, UK, November

Andy Sands / Wood spurge (Euphorbia amygdaloides) Close up of flowers ancient woodland indicator species, Hertfordshire, England, UK, April. Focus Stacked

Andy Sands / Wood anemone (Anemone nemorosa) flowering en-masse under coppice woodland a good ancient woodland indicator species, Suffolk, England, UK, April

Andy Sands / Wild Service Tree (Sorbus torminalis) Close up of leaves and flower buds a good ancient woodland indicator species, Cambridgeshire, England, UK, April

Andy Sands / Small leaved lime / Pry Tree (Tilia cordata) Veteran tree that was once a coppice stool but has remained un-cut for around 100 years plus, ancient woodland indicator species, Suffolk, England, UK, Apr...

Andy Sands / Small leaved lime / Pry Tree (Tilia cordata) Ancient coppice stool growing in managed woodland, ancient woodland indicator species, Suffolk, England, UK, May

Andy Sands / Small leaved lime / Pry Tree (Tilia cordata) Close up of leaves, ancient woodland indicator species, Suffolk, England, UK, May

Andy Sands / Small leaved lime / Pry Tree (Tilia cordata) veteran tree that was once a coppice stool but has remained un-cut for around 100 years plus. Ancient woodland indicator species, Suffolk, England, UK, Apr...

Ashley Cooper / Electric vehicle at a recharging station on the street in Berkeley Square, London, UK. May 2012.

Ashley Cooper / Electric vehicle at a recharging station on the street in Berkeley Square, London, England, UK. May 2012.

Adrian Davies / Toothwort (Lathraea squamaria), parasitic on hazel (Corylus avellana) tree roots, ancient woodland indicator species. Surrey, England, UK. April.

Adrian Davies / Toothwort (Lathraea squamaria), parasitic on hazel (Corylus avellana) tree roots, ancient woodland indicator species. Surrey, England, UK. April, 2018.

Adrian Davies / Toothwort (Lathraea squamaria), parasitic on hazel (Corylus avellana) tree roots, ancient woodland indicator species. Surrey, England, UK. April.

Dong Lei / Yellow-rumped honeyguide (Indicator xanthonotus) on honeycomb, Yarlung Zangbo Grand Canyon National Park, Tibet, October.

Ann & Steve Toon / Greater honeyguide (Indicator indicator) at water. Zimanga private game reserve, South Africa. September.

Matthew Maran / Wild service tree (Sorbus torminalis) 1 of only 19 on the Heath. This species is an ancient woodland indicator species Hampstead Heath, London, England, UK.

Chris Mattison / Lemon slug (Malacolimax tenellus - formerly Limax tenellus) - an indicator of ancient woodland that feeds mainly on fungi, UK. May.

Roland Seitre / Black-throated honeyguide (Indicator indicator) Fathala Reserve, Senegal.

Roland Seitre / Black-throated honeyguide (Indicator indicator) Fathala Reserve, Senegal.

Roland Seitre / Black-throated honeyguide (Indicator indicator) Fathala Reserve, Senegal.

Roland Seitre / Black-throated honeyguide (Indicator indicator) Fathala Reserve, Senegal.

Roland Seitre / Black-throated honeyguide (Indicator indicator) feeding on honey comb, Makasutu forest, Banjul, Gambia.

Roland Seitre / Black-throated honeyguide (Indicator indicator) feeding on honey comb, Makasutu forest, Banjul, Gambia.

Roland Seitre / Black-throated honeyguide (Indicator indicator) feeding on honey comb, Makasutu forest, Banjul, Gambia.

Chris Mattison / Mountain pansies (Viola lutea) growing on spoil heap near an old lead mine (Magpie Mine) Derbyshire, England, UK, May.

Ross Hoddinott / 2020VISION / Wild garlic / Ramsons (Allium ursinum) flowering in woodland, Cornwall, England, UK, May. Did you know? Wild garlic is an ancient woodland indicator species.

Ross Hoddinott / 2020VISION / Wild garlic / Ramsons (Allium ursinum) flowering in woodland, Cornwall, England, UK, May. Did you know? Wild garlic is a good indicator of an ancient woodland.

Juan Manuel Borrero / Illustration of Honey Badger - (Mellivora capensis) and Greater Honeyguide (Indicator indicator). Pencil, watercolor and pastel illustration

Christophe Courteau / Nest of Greater Honeyguide bird (Indicator indicator) hanging in tree, Okvango, Botswana

Christophe Courteau / Nest of Greater Honeyguide bird (Indicator indicator) hanging in tree, Okvango Delta, Botswana

Christophe Courteau / Nest of Greater Honeyguide bird (Indicator indicator) hanging in tree, Okvango, Botswana

Mark Hamblin / 2020VISION / RSPB scientist studying aquatic invertebrate adundance as part of Common Scoter (Melanitta nigra) research, Forsinard Flows RSPB reserve, Flow Country, Sutherland, Highlands, Scotland, UK, June 2011....

Chien Lee / Malaysian Honeyguide (Indicator archipelagicus) female, Sarawak, Borneo, Malaysia

Ian Lockwood / Muddy water flows through the Ravana Ella falls after a pre-monsoon deluge. It is an indicator of aggressive agricultural practices upstream. Sri Lanka, August 2010

Adrian Davies / Beard Lichen (Usnea subfloridana) a good indicator of clean air, UK

Michael Durham / Chocolate Labrador Retriever (Canis familiaris) named CJ, indicating he has located a bat roosting site in old ponderosa snag, Coconino National Forest, Arizona

Michael Durham / Chocolate Labrador Retriever (Canis familiaris) named CJ, sitting to indicate he has located a bat roosting site, Coconino National Forest, Arizona

Jason Smalley / Riverbank showing erosion with Water dock as flood indicator, River Dee, Cheshire, UK.

Ralph Pace / Pelagic Red Crab (Pleuroncodes planipes), indicator of El Nino, California

Ralph Pace / Pelagic Red Crab (Pleuroncodes planipes), indicator of El Nino, California

Ralph Pace / Pelagic Red Crab (Pleuroncodes planipes), indicator of El Nino, California

Sebastian Kennerknecht / Santa Catalina Island Fox (Urocyon littoralis catalinae) biologist, Julie King, placing collar on unvaccinated male to act as an early indicator for canine distemper virus, Santa Catalina Island, Chan...

Tui De Roy / Kakapo (Strigops habroptilus) biologist climbing tree to count unripe seeds which will be an indicator whether the kakapo will breed this year, Codfish Island, Southland, New Zealand

Staffan Widstrand / Hypocenomyce scalaris lichen growing on burnt wood in forest, an indicator of continuous forest growth, Iggejaur-Varjisan-Labtjevare, Norrbotten, Sapmi, Lapland, Sweden. August.

Graham Eaton / Within the Cambrian, Gwna Group, here is an excellent example of S-C fabric within schistose metasediments. S stands for Schistosity and C means Cisaillement (meaning scissor type movement in French)....

Nigel Cattlin / Barley (Hordeum vulgare) grain, cross sections of seeds treated with tetrazolium salt which stains viable living tissue red, a test for germination.

Nigel Cattlin / Barley (Hordeum vulgare) germination test, seed treated with tetrazolium salt. Grains stained red are viable, colourless grains are not viable.