Effects of logging on stream environments and faunas in Nelson

Abstract

The effects of various logging practices on stream environments and faunas were studied at the Golden Downs State Forest in Nelson. Comparisons were made between the features of a control stream with an unmodified forest catchment and three streams whose catchments had been affected by different logging practices. Measurements were made of stream flow, water temperature, stream bed sedimentation, suspended sediment and dissolved solids concentrations, and the abundance of benthic invertebrates and fishes.Clearfelling to the stream's edge, together with inappropriate roading and bridging techniques, caused great changes in stream environments and faunas. Excessive amounts of waste timber and soil entered streams and stream bed loads, and suspended sediment and dissolved solid concentrations increased. In comparison to the control stream water temperatures increased in summer by up to 6.5 c c and decreased in winter by as much as 2.5°c. In one stream the benthic invertebrate fauna was greatly modified; there was a reduction in the abundance of Plecoptera and certain Ephemeroptera nymphs, and an increase in the abundance of oligochaetes. chironomids, and Deleatidium nymphs. Fishes, Galaxias divergens and Anguilla dieffenbachi, were also reduced in numbers in this stream.In January 1971 numerous brown trout (Salmo trutta) and other fishes died in the Motueka River, and there are indications that this was due in part to low dissolved oxygen concentrations following excessive sedimentation of the river bed caused by unsatisfactory logging practices. In general, the physical and chemical changes found in the stream environments were similar to those found overseas, but those noted in the invertebrate and fish fauna were rather different, e.g., logging had different effects on the abundance of Diptera, Ephemeroptera, and Trichoptera, and on trout survival and migration. The data collected will be of some value in assessing the effects of this type of logging on other streams and their biotas in the Nelson region.A protective buffer strip of unlogged vegetation was left alongside one stream and the remainder of the catchment was clearfelled. In comparison to the other streams there was relatively little change in the aquatic environment and fauna. Although stream flows and nitrate concentrations were considerably higher than in the control stream, these differences may have been natural and not a consequence of the logging operations. Similar results have been found overseas, and it is concluded that provided measures are taken to reduce erosion, buffer strips will be effective in reducing the effects of logging operations on stream environments and their faunas in other forests throughout New Zealand.

Relationships between riparian buffer widths and the effects of logging on stream habitat, invertebrate community composition and fish abundance

“…Logging operations that impinge on the stream channel directly or by the influence of road crossings are also associated with increases in sediment input and consequent declines in water quality and stream habitat integrity (e.g. Graynoth 1979;Culp and Davies 1983;Richardson 1985;Borg et al 1988), leading to declines in abundance of invertebrates and fish. Removal or input of logging debris may also have a significant impact on stream channel form and faunal abundance and diversity (Lisle 1986).…”

Effect of land use on the distribution and abundance of native fish in tributaries of the Waikato River in the Hakarimata Range, North Island, New Zealand

“…Logging of forested catchments may affect many features of a stream's physical characteristics including light levels, water temperatures, waterflow patterns, water quality including sediment loads, stream bed characteristics, and stream bank stability (Morgan & Graynoth 1978;Graynoth 1979). Increased light penetration increases primary productivity of the streams (Murphy etal.…”

“…1981), and also gives rise to elevated summer temperatures and greater daily fluctuations in temperature. Increased siltation fills interstitial spaces which may reduce the diversity andabundance of the benthic macroinvertebrate community (Graynoth 1979;Silsbee & Larson 1983). The loss of riparian vegetation reduces the amountof instream cover for fish as a result of either the absence of fallen logs and branches, or the collapse of undercut banks which is normally prevented by the soil binding properties of roots (Murphy et al 1981;Silsbee & Larson 1983).…”

Conservation status of the only Lungless Frog Barbourula kalimantanensis Iskandar, 1978 (Amphibia: Anura: Bombinatoridae)

“…In a logged area, water temperature is found to be warmer than in the non-logged area (Graynoth 1979;De Groot et al 2007). The effect of temperature increase for B. kalimantanensis is clear.…”