A number of flora and fauna are found in the Buller catchment, many of these extending onto the slopes of the Paparoa Range.

[6] The river is suitable for contact recreation approximately 95% of the time, though Tasman Council recognises it needs to be better because of the popularity of whitewater kayaking below Gowan Bridge.

[2] 93% of the water comes from the western mountains, which make up only 38% of the catchment, and it is highest in summer, partly due to melting snow.

[16] One migratory resource was Ngāi Tahu's pounamu trade, which had a greenstone trail through the valley,[17] probably in summer, when the river would usually be lower.

[18] By virtue of a taua of 1829–1832, Ngāti Toa Rangatira was recognised in 2012 as having an interest in the upper part of the river.

He describes the valley through which the river runs to be twenty miles wide, finely wooded, with some open land.

"[21] In 1846 Brunner was the first European to follow the full length of the Buller, together with his guide, E Kehu, of Ngāti Tūmatakōkiri, who already knew the area well[20] (Ekehu had been taken prisoner by Ngāi Tahu while living near the Grey River).

[23] The journey was so difficult that they left Lake Rotoiti on 31 December 1846, but only reached the mouth of the river on 4 June 1847.

[26] A West Coast gold rush, coal mines and timber sawmills resulted in a rapid population increase in the 1860s.

By 1867 there were 6,087 miners in Nelson Province and 10,466 people (and 1,612 tents, indicating the temporary nature of their stay) in Westland North, which also included the Grey valley.

[29] The original Māori name for the Buller may have been Kawatiri, although Patrick O'Regan thought that was a misunderstanding of Ka Awatiri.

[29] Organs Island was created, about 6 km (3.7 mi) upstream from Westport,[30] when a loop in the Buller was bypassed[31] by a straight flood relief channel built between 1882[32] and 1886.

[50] The first Newman Brothers coach ran between Foxhill (end of the Nelson railway) and Hampden (Murchison) on 22 July 1879,[51] following improvements to the road,[52] was extended to Lyell in 1880 and, by Job Lines, to Reefton in 1882.

[58] In 1964 the Nelson-Murchison Railways Road Services route was taken over by Nelson Suburban Bus Co.[59] In 1846 the land around what was later Westport was described as covered to the river edge with totara and kahikatea.

[113] Other birds include Australasian bittern (matuku hūrepo) long-tailed cuckoo (koekoeā), New Zealand falcon (kārearea), fernbird (kōtātā), New Zealand pipit (pihoihoi), rifleman (titipounamu), western weka[114] kererū, tūī, korimako, riroriro, pīwakawaka, tauhou and morepork (ruru).

[116] Rhytida meesoni perampla snail, Leaf-veined slugs and many insects live in the valley, including the striped dung fly, Mycetophila fungus gnats, West Coast tree weta, Wellington tree weta, Kahurangi ground wētā,[114] and Hakaharpalus and Kiwitrechus beetles.

[117] European wasps have become a problem in the beech forests since their spread in the 1970s,[118] being known to kill and compete for food with lizards and other native species.

[122] Lake Rotoiti was created by a glacier and glacial moraines occupy a large area between the Buller and Gowan rivers.

[133] Gold is in quartz veins near Lyell, deposited by hydrothermal fluids, created by metamorphosis, about 420 million years ago.

[124] In 1972 the mountains on either side of the Gorge were officially named Mounts Cassin[135] and Jacobsen, after the men who discovered the uranium.

Other smaller tributaries include the Hinemoatū / Howard, Hope, Owen, Mangles, Matiri, Newton, Orikaka, Blackwater, Ohikaiti and Ohikanui Rivers.