Ecology-- Biodiversity-- Conservation 167 Ecology-- Biodiversity-- Conservation-- Ecosystems 128 Marine ecology-- Ocean ecology-- Sea ecology 108 Aquatic ecology-- Fresh water ecology-- Pond ecology-- Limnology 63 Aquatic ecology-- Fresh water ecology-- Pond ecology-- Limnology (biology)-- groundwater ecology 49 Environmental management 41 ECOLOGY 39 Environmental ecology-- Island ecology-- Desert Ecology 39 Water pollution-- Aquatic ecology 39 Estuaries- Ecology 34 Environmental pollution-- Effects of humans, pollution on ecology 31 Environmental pollution-- Effects of humans-- pollution on ecology 31 Marine pollution-- Pollution in Ocean 30 Aquatic ecology-- Fresh water ecology-- Pond ecology-- Limnology (biology)-- groundwater ecology-- Periph 29 Population biology 29 Malayalam; Enviornment Study 26 Ecosystems 23 Forest ecology 22 Environmental management-- Ecosystems 20 A LABORATORY BLOCK FIELD ECOLOGY 18 മലയാളം; പരിസ്ഥിതിപഠനങ്ങള്‍ 18 Water pollution 17 Statistical ecology 16 മലയാളം; പരിസ്ഥിതി പഠനം 15 Malayalam;Ecology/Enviornment 14 Specific factors affecting ecology 14 Environmental chemistry 13 Soil ecology 13 ecology 13 Ecology 12