Characterisation and classification of benthic invertebrate communities in 88 New Zealand rivers in relation to environmental factors

Abstract

Benthic macroinvertebrates were sampled (seven Surber samples per site) in 88 rivers throughout New Zealand in "runs" (velocity 0.4-0.8 m s" 1 , depth = 0.3-0.6 m), under autumn baseflow conditions (Q < median). Medians and 10-90 percentiles for the following community level characteristics were: taxa richness, 14 and 7-20(0.7 m -2 ); Shannon Diversity (H'), 1.33and 0.80-1.90; total density, 1900 and 230-6700 nr 2 ; and total biomass, 0.608 and 0.112-2.932 g AFDW nr 2 . Invertebrate abundance and taxonomic richness were lowest in rivers with beds of silt or sand, or cobbles overlain with sand deposits. Comparisons of environmental factors between sites grouped by TWINSPAN indicated that the degree of catchment development to improved pasture, water temperature, and level of enrichment (indicated by increased nutrients and periphyton biomass) are important factors affecting invertebrate community structure in New Zealand rivers. Mayflies, stoneflies, and predatory caddisflies were associated with cooler, less enriched, steeper, and more elevated sites than snails, crustaceans, chironomids, and worms. Stonefly biomass was minimal at sites having mean annual temperatures >13°C. The following community characteristics emerged as useful indicators of the level of water enrichment: the Macroinvertebrate Community Index (MCI) and its quantitative analog (QMCI); the presence of some species (e.g., Zelandoperla decorata and Bereoptera roria), and the densities of some widely distributed taxa (e.g., M90014Received 5 March 1990; accepted 23 May 1990 Deleatidium spp. and Psilochorema spp.); percentage predator biomass; and the number of ephemeropteran, plecopteran, and trichopteran taxa (EPT). Sites did not separate out clearly into ecoregions, although rivers with "clean-water" faunas were more predominant in the South Island than in the North Island. This is thought to reflect the greater degree of development of the North Island catchments.

Age and growth of longfinned eels (Anguilla dieffenbachii) in pastoral and forested streams in the Waikato River basin, and in two hydroelectric lakes in the North Island, New Zealand

“…Streams in native forest have lower food availability than pastoral streams because fish and invertebrate biomass may be low (Taylor 1988;Hanchet 1990;Quinn & Hickey 1990), and vegetation inhibits overland run-off. Low abundance of fish in upper catchments probably limits piscivory by longfinned eels, and could impair growth compared with lower catchments where fish are more plentiful.…”

“…The fast to moderate growth rates of longfinned eels in pastoral streams are likely to be influenced by several important factors which may include: water temperature, high food abundance (Taylor 1988;Quinn & Hickey 1990), low gradients that cause low water velocities and a high proportion of pool habitat, intraspecific competition, and interspecific competition with shortfinned eels.…”

Effects of hydraulic conditions and larval size on the microdistribution of Hydrobiosidae (Trichoptera) in two New Zealand rivers

“…Representatives of the caddisfly family Hydrobiosidae are widely distributed in rivers throughout New Zealand (Quinn & Hickey 1990) where they can be relatively abundant (e.g., Winterbourn 1978) and comprise important components in the diet of some fish (e.g., Sagar & Eldon 1983;Stephens 1989;Glova & Sagar 1991). The relatively high mobility of the larvae may enable them to adjust to rapidly changing hydraulic conditions in a river, and they might therefore be expected to exhibit strong relationships with hydraulic variables.…”

Longitudinal patterns of macroinvertebrate communities in relation to environmental factors in a Tibetan-Plateau river system

“…To use macroinvertebrates as ecological indicators, one necessary approach is to accumulate taxonomical and ecological information for establishing reference conditions. It is also important to determine how natural-induced factors control distribution patterns of macroinvertebrates, as high altitude river systems are usually strongly influenced by natural disturbances such as floods (Quinn and Hickey, 1990;Chaves et al, 2005), droughts (leading to a loss of hydrological connectivity) (Lake, 2003;Bonada et al, 2006), temperature (Maiolini and Lencioni, 2001), and the solubility of oxygen (Jacobsen et al, 2003).…”