Food webs from the Lerderderg River, an intermittent stream in Victoria, Australia, were compiled with aim of examining changes food web structure a highly variable habitat. Emphasis was placed on high degree taxonomic precision. Spatial and temporal variation assessed by partitioning study area into three sites, located ≈1.5 km apart along river. Sites differed overall width length low streamflow period during summer. Three separate for each site four different times year. Relatively little...

Abstract: In times of biodiversity crisis there is an increasing need for faster and cheaper methods by which to achieve conservation goals. This situation especially troublesome invertebrates, the use morphospecies instead taxonomic species has been proposed as a way around constraints in particular situations. We conducted study modified native shrubland on New Zealand's South Island we sampled Lepidoptera, Coleoptera, Araneae autumn beating pitfall traps. All specimens were separated into...

Summary 1. Hypoxic conditions occur frequently during hot, dry summers in the small lentic waterbodies (billabongs) that on floodplains of Murray‐Darling River system Australia. Behavioural responses to progressive hypoxia were examined for native and introduced floodplain fish Ovens River, an unregulated tributary Murray south‐east 2. Given high frequency hypoxic episodes billabongs floodplain, it was hypothesised all species would exhibit behaviours confer a degree hypoxia‐tolerance....

Summary Some native fish in New Zealand do not coexist with introduced salmonids. Previous studies of disjunct distributions exotic brown trout Salmo trutta and galaxiids demonstrated extirpation except where major waterfalls prevented upstream migration trout. In the Manuherikia River system, we predicted that water abstraction might be a further factor controlling spatial distribution both invader fish. We applied multiple discriminant function analyses to test for differences...

Summary Amphidromy is a widespread migratory behavioural syndrome exhibited by fish (and some aquatic invertebrates) that spawn in fresh water and whose larvae migrate to pelagic marine (or lentic) habitats for period of early growth, followed return migration adult freshwater habitats. The fitness advantage amphidromy has been the subject prolonged debate, we examined hypothesis mainly increases fecundity through production small larvae. We compared egg size (a proxy larval size) closely...

The use of morphospecies as surrogates for taxonomic species has been proposed an alternative to overcome the identification difficulties associated with many invertebrate studies, such biodiversity surveys. Hymenoptera specimens were collected by beating and pitfall traps, separated into a non-specialist no prior training, later identified expert taxonomist. number was 37 42, respectively, representing underestimation error 12%. Different families presented varying levels difficulty,...

Abstract Macroinvertebrate community composition was compared across streams draining catchments dominated by either native bush, agricultural or urban land uses within the Water of Leith stream catchment near Dunedin, New Zealand. Land use associated with differences in taxon richness and faunal communities present each stream. The mean abundance levels Ephemeroptera, Plecoptera, Trichoptera were highest bush catchments, lowest catchments. In contrast, Oligochaeta exhibited opposite...

Individuals within a species often compete for resources in both space and time.In dominance hierarchies individuals with the greatest competitive ability will occupy prime locations during optimal periods.We compared spatial temporal use of habitat, aggression, feeding success among giant kokopu (Galaxias argenteus) under normal reduced food supply.Under supply conditions dominant fish were predominantly nocturnal maintained large home ranges at night.Conversely, subdominant diurnal...

Summary 1. Seasonal variation in microhabitat use and activity of 14 giant kokopu Galaxias argenteus , a drift‐feeding galaxiid fish, was compared using radiotelemetry. 2. During winter predominantly used low velocities intermediate depths by night day. Activity recorded during 24 72 h periods indicated that fish were consistently active at inactive the data corresponded with point‐in‐time habitat data, both which concealed amongst cover day open water habitats night. 3. summer, higher...

Long-term patterns of residency, growth, and movement among drift-feeding fish in relation to their social status macroinvertebrate drift were determined. Each month, over 21 months, we quantified drift, abundance, biomass, recorded individual lengths, weights, rank, monitored diel activity residing different pools. Despite marked variation food supply between pools, average growth rates within each pool not significantly different. However, size the largest (dominant) (i.e., ones that had...

Histological analysis of the skin common bully Gobiomorphus cotidianus , a New Zealand native eleotrid fish, revealed presence club cells in epidermis. Epidermal are frequently associated with production alarm substance (Schreckstoff). The behavioural responses perch‐naïve and perch‐experienced bullies to either conspecific extract or chemical cues from an introduced predator, perch Perca fluviatilis were then examined. Both exhibited response when exposed extract, indicating probable...

Summary 1. We studied the spatial organisation of littoral, benthic invertebrate communities in two large oligotrophic lakes with very extensive heterogeneous littoral zones, and report that show significant variation their structure at multiple scales. 2. At coarser scales, zone topography, riparian inputs exposure may be important drivers community structure. finer composition substrates, particularly macrophytes inorganic sediments, 3. The effects substrates on patterns were non‐additive...

Summary 1. Numerous interacting abiotic and biotic factors influence niche use assemblage structure of freshwater fishes, but the strength each factor changes with spatial scale. Few studies have examined role interspecific competition in structuring stream fish assemblages across scales. We used field laboratory approaches to examine microhabitat partitioning effect on two sympatric fishes ( Galaxias ‘southern’ gollumoides ) at large (among streams among sites within streams) small (within...

Abstract Otolith microchemistry of common bullies (Gobiomorphus cotidianus) collected from the lower reaches Mataura, Clutha, and Taieri/Waipori River systems New Zealand was examined using particle induced X‐ray emission (PIXE). High strontium:calcium (Sr:Ca) ratios in otolith cores relative to edges suggested either diadromous or estuarine‐reared are present all three systems, including fish Clydevale (50 km inland) on Clutha River. However, constant slightly variable Sr:Ca core edge,...

Summary Land use change due to intensifying agricultural practices has profound effects on streams and rivers worldwide, been identified as an important source of fine sediment inputs affecting both habitats biota. Although the sedimentation stream organisms have widely studied, manipulative field experiments involving fish conducted at reach scale are lacking. Further, it is unknown whether experimentally removing from can reverse negative impacts sedimentation. Two farmland were...

Understanding migratory life histories is critical for the effective management and conservation of species. However, amphidromous migrations (fish hatch in streams, immediately migrate to sea a feeding period return fresh water as juveniles) remain understudied owing difficulties tracking tiny larval fish. Despite this, it has widely been assumed that fish have open, resilient populations, with marine-rearing larvae dispersing during their pelagic phase. In present study we tested...