Biodiversity values of small headwater streams in contrasting land uses in the Auckland region

Abstract

The biodiversity values of 12 small headwater streams (catchments mostly B30 ha) were evaluated. Densities of aquatic macroinvertebrates were the same or higher in three headwater habitats (flowing water, isolated pools and wet mud) as in adjacent perennial streams. Alpha (per sample) richness of all aquatic macroinvertebrates and of Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa were as high in headwater flowing habitats and isolated pools as in perennial streams. Gamma (landscape-level) and beta (taxa turnover) richness appeared to be similar among isolated pools, mud habitats and perennial streams, but higher in headwater flowing habitats. Community composition was very similar among headwater flowing, isolated pool and perennial habitats. Some taxa in headwater habitats were headwater specialists, but none was identified as endemic to headwaters. Thus, macroinvertebrate evidence indicates that headwater streams should be given similar protection status to perennial reaches. Headwaters in pasture catchments had lower EPT richness than native forest headwaters. Riparian native woody vegetation appeared effective in maintaining EPT richness and community composition similar to the native forest condition.

Predicting fine‐scale distributions of peripheral aquatic species in headwater streams

“…Headwater streams provide many unique functions across a landscape and are important terrestrial-aquatic and headwater-downstream linkages (Meyer et al 2001(Meyer et al , 2007Lowe and Likens 2005;Wipfli et al 2007;Clarke et al 2008;Storey et al 2011). Strahler stream order was identified as the most influential variable in two of the three final models and the second most influential variable in the other model, which supports our decision to generate our own stream network that represents headwater streams and potential species ranges more consistently across the study area.…”

“…; Storey et al. ). Strahler stream order was identified as the most influential variable in two of the three final models and the second most influential variable in the other model, which supports our decision to generate our own stream network that represents headwater streams and potential species ranges more consistently across the study area.…”

“…; Storey et al. ). The biota of headwater streams represent many functional biological groups that are important components of biodiversity in a river network.…”

“…Headwater streams are often underrepresented in commonly used topographic maps in the United States and abroad despite their prevalence on the landscape and the importance of their hydrologic and biological form and function (Meyer et al 2007;Storey et al 2011). The biota of headwater streams represent many functional biological groups that are important components of biodiversity in a river network.…”

The importance of scale in understanding the effect of stream intermittence on aquatic macroinvertebrate diversity

“…However, this effect might be offset by high β‐diversity in intermittent reaches. In one of the few studies examining α, β, and network diversity in intermittent and perennial reaches, Storey, Parkyn, Neale, Wilding, and Croker () found that intermittent and permanent reaches had similar α‐diversities but intermittent reaches had higher β‐diversities and higher network diversity. The authors attributed higher β and network diversity to greater habitat diversity in intermittent reaches.…”