It is the largest salix swamp forest in north-eastern India, with a tropical monsoon climate with a hot and wet summer and cool and usually dry winter.

[1][2] In December 2020, Gauhati highcourt stayed a permission given to Oil India Limited for hydrocarbon exploration at seven locations inside the protected area.

Major tree species of the area are tetrasperma, Dillenia indica, Bischofia javanica, Bombax ceiba, Lagerstroemia parviflora, Terminalia myriocarpa, Mesua ferrea, Dalbergia sissoo, and Ficus.

Arundo donax, Imperata cylindrica, Phragmites karka, Saccharum ravennae are principal types of grasses in the national park.

[7] Species include Bengal tiger, Indian leopard, clouded leopard, jungle cat, sloth bear, dhole, small Indian civet, Malayan giant squirrel, Chinese pangolin, Ganges dolphin, slow loris, pig tailed macaque, Assamese macaque, rhesus macaque, capped langur, Hoolock gibbon, Asian elephant, wild boar, Sambar deer, hog deer, barking deer, Asiatic water buffalo,[8] and feral horse.

[citation needed] Birds recorded include greater adjutant, ferruginous pochard, Jerdon's babbler, black-breasted parrotbill, marsh babbler, puff-throated babbler, Jerdon's bushchat, rufous-rumped grassbird, chestnut-crowned bush warbler,[11] swamp francolin, spot-billed pelican, white-bellied heron, grey heron, purple heron, black-crowned night heron, yellow bittern, Asian openbill, lesser adjutant, white-necked stork, black stork, black-necked stork, glossy ibis, fulvous whistling-duck, bar-headed goose, greylag goose, northern pintail, common shelduck, white-winged wood duck, Indian spot-billed duck, Baer's pochard, white-tailed eagle, Pallas's fish eagle, grey-headed fish eagle, greater spotted eagle, Himalayan griffon, white-backed vulture, slender-billed vulture, osprey, crested serpent-eagle, lesser kestrel, Sarus crane, Bengal florican, brown fish owl, great pied hornbill, spotted redshank, greenshank, and pale-capped pigeon.