Related by context. Frequent words. (Click for all words.) 61 forest ecosystems 61 ecosystems 58 grasslands 57 habitats 57 forbs 57 grassland birds 57 wetland habitats 56 temperate forests 56 terrestrial ecosystems 56 forests 56 habitat 56 rangelands 55 temperate zones 55 habitat fragmentation 55 grassland 55 rangeland 54 vegetation 54 freshwater ecosystems 54 ecology 54 aquatic habitats 54 insect populations 54 forest ecologist 53 biodiversity 53 forage 53 biome 53 species 53 soil fertility 52 flora 52 oak woodland 52 genetic diversity 52 saltcedar 52 wildlife ecologist 51 boreal forests 51 woody plants 51 giant sequoias 51 biota 51 tropical rainforests 51 amphibian populations 51 perennial grasses 51 nesting habitat 51 genetic variability 51 nitrogen fixation 51 herbaceous plants 51 ecologist 51 hickories 51 arid lands 51 aquatic ecosystem 51 understory 51 tropical forests 51 wetland habitat 51 semiarid 51 aquatic ecosystems 51 nonnative plants 50 riparian habitat 50 agroforestry 50 savannahs 50 oak woodlands 50 grasses 50 wildlife habitat 50 grazing 50 tallgrass prairie 50 conserve biodiversity 50 prairie grasses 50 savanna 50 ecologies 50 savannas 50 wildlife 50 spotted knapweed 50 keystone species 50 ant species 49 jack pine 49 Chihuahuan Desert 49 arid regions 49 sagebrush habitat 49 overgrazing 49 tropical forest 49 nutrient uptake 49 black footed ferrets 49 wildlife habitats 49 woodlands 49 ungulates 49 biocontrol 49 soils 49 pasturelands 49 genetically pure 49 microflora 49 conifers 49 flora fauna 48 hardwood forests 48 lodgepole 48 pollinating insects 48 adelgids 48 Phytophthora 48 longleaf pine 48 semi arid 48 avian species 48 drylands 48 soybean aphid 48 pronghorns 48 wildlands 48 megafauna