Persistence and stability of lotic invertebrate communities in New Zealand

Abstract

1. Persistence and stability of lotic invertebrate communities were determined at an annual time scale over a 9‐year period (1990–98) at 26 river sites over the northern half of New Zealand. In addition, a number of water quality variables were measured monthly and flow information collected continuously over the same period at each site. 2. The aim of the study was to describe the levels of interannual variability in invertebrate communities, and relate community changes to variability in environmental conditions. The consequences of this temporal variability for the sensitivity of predictive models were also investigated. 3. Levels of change in environmental conditions varied significantly between years, but were relatively similar across sites. In contrast, community persistence (similarity between years in species assemblage composition), and stability (similarity between years with respect to relative abundance of species in the community) both varied significantly between sites, but changes between years were similar. Community stability was highest at sites with relatively harsh flow conditions (high coefficient of variation, high relative size of floods), and was also greater in communities dominated by Ephemeroptera. 4. Relationships between change in environmental conditions and changes in community composition and structure were relatively weak for most individual sites. However, when average levels of change for each of the 26 sites were used, communities showed greater persistence under conditions where flow conditions remained relatively constant. Water quality changes had no significant effect on community persistence when assessed for all 26 sites combined. 5. Results from this study suggest that lotic invertebrate communities fluctuate around a relatively stable state, at least over a 9‐year period. However, the extent of interannual variation in community composition and structure observed, along with the relatively low degree of cluster fidelity observed within a single region, suggests that predictive models based on reference site conditions extrapolated over several years should be applied with caution in New Zealand streams.

Effect of daily variation on the seasonality of testate amoebae community structure in different environments of a Neotropical floodplain

“…Other studies have reported high variability in macroinvertebrate and fish communities under relatively constant environmental conditions (Moyle and Vondracek, 1985;Townsend et al, 1987;Weatherley and Ormerod, 1990;Scarsbrook, 2002;Milner et al, 2006). Our results suggest that variability in environmental factors was not detected due to characteristics of the water body.…”

Inter-annual patterns in the stability and persistence of stream macroinvertebrate communities: relationship with water physicochemical parameters

“…Stability is defined as the degree of constancy in numbers, or relative abundance of organisms, whereas persistence refers to the continued presence of particular species in a community (Holling 1973;Connell and Sousa 1983;Scarsbrook 2002;Milner et al 2006;Collier 2008). Construction of the Three Gorges Reservoir (TGR) led to anthropogenic perturbations in local streams and a changed the stream environment.…”

“…However, relationships between changes in environmental conditions and changes in community stability and persistence are relatively complex. Scarsbrook et al (2002) studied macroinvertebrate communities in New Zealand over a nine-year period and showed that persistence and stability were significantly related to the flow conditions, while there was no significant response to water quality changes. Brown et al (2006) showed that in alpine streams water quality variables (water temperature and suspended sediment concentration) were more important to stability than water quantity because of taxa possessing adaptations to flow variability.…”

Macroinvertebrate community response to inter‐annual and regional river flow regime dynamics

“…Results from the available long-term hydroecological studies indicate that instream communities are influenced by variations in both the climatological (Bradley and Ormerod, 2001;Daufresne et al, 2003;Scarsbrook et al, 2003) and hydrological regimes (e.g., Lamouroux et al, 2006;Monk et al, 2006, Scarsbrook, 2002Wagner and Schmidt, 2004;Wood et al, 2001). However, attempts to quantify macroinvertebrate community response to river flow variability, and in particular high and low flows, are currently limited in terms of their temporal (typically <5 years study period) and/or geographical coverage (e.g., Caruso 2002;Clausen and Biggs, 1997;Sheldon and Thoms, 2006;Suren and Jowett, 2006).…”