Related by context. Frequent words. (Click for all words.) 71 boreal forests 68 temperate forests 65 boreal forest 64 boreal 63 Boreal Forest 62 ecosystems 60 tropical rainforests 60 freshwater ecosystems 59 forests 58 rainforests 58 tropical forests 58 forest ecosystems 58 biodiversity hotspots 58 terrestrial ecosystems 58 hardwood forests 56 peat bogs 56 virgin forests 56 drylands 56 wetland habitats 55 temperate zones 55 Amazon rainforest 54 grasslands 54 biodiversity 54 Rainforests 53 tropical rainforest 53 biologically diverse 53 amphibian populations 53 subarctic 53 caribou herds 53 biodiverse 52 sequoias 52 habitats 52 mountain glaciers 52 subtropical regions 52 carbon sinks 52 woodland caribou 51 river deltas 51 savannas 51 biota 51 species extinctions 51 coral reef ecosystems 51 woodlands 51 Polar Regions 51 aquatic ecosystems 51 biomes 51 tropical forest 51 Warming temperatures 51 lake sediments 50 coastal ecosystems 50 freshwater lakes 50 rainforest 50 coral species 50 species 50 barrens 50 savannahs 50 temperate regions 50 prairies 50 Amazon Rainforest 50 peatlands 50 glaciers 49 Large swathes 49 tidal marshes 49 lowlands 49 megafauna 49 Arctic tundra 49 stratospheric ozone 49 temperate 49 mammal species 49 Severe drought 49 oceans 49 Droughts 49 amphibian species 48 icecaps 48 prolonged droughts 48 softwoods 48 biome 48 pine forests 48 tallgrass prairie 48 subtropics 48 Coral reefs 48 ocean ecosystems 48 tropics 48 marine ecosystems 48 ecologies 48 marine sediments 48 atmospheric methane 48 conserve biodiversity 48 breathtaking landscapes 48 driest continent 48 permafrost 48 Amazon basin 47 sediment cores 47 stratospheric ozone layer 47 polar caps 47 eucalypts 47 oak woodlands 47 bird species 47 coral reefs 47 kelp forests 47 clearcuts 47 degrees Fahrenheit warmer