Conditional effects of aquatic insects of small tributaries on mainstream assemblages: position within drainage network matters

2014 ◽  
Vol 71 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Silvia Vendruscolo Milesi ◽  
Adriano Sanches Melo
Keyword(s):  
Spatial Heterogeneity ◽  
Aquatic Insects ◽  
Drainage Network ◽  
Stream Networks ◽  
Assemblage Composition ◽  
Nested Subsets ◽  
Aquatic Fauna ◽  
Bottom Substrate ◽  
Conditional Effects ◽  
Composition And Structure

Tributaries may affect fauna in a mainstream by changing bottom substrate and increasing spatial heterogeneity. Additionally, we hypothesized that fauna in the mainstream may be affected by drifting migrants from tributaries. In nine stream networks, we sampled a similar microhabitat immediately upstream and downstream of two confluences. In each network, one confluence was located in the network centre and one in the periphery, and they were distinguished by low and high ratios of tributary size, respectively. We assessed whether the aquatic fauna at sites downstream from confluences was species-richer, distinct in composition and structure, and whether it included the fauna of upstream sites. We found that richness, rarefied richness, and abundance at downstream sites were not higher than at their upstream counterparts. Faunas at downstream sites were not nested subsets of those at upstream sites. Macroinvertebrate assemblage composition and structure differed between downstream and upstream sites in the peripheral confluences (high tributary to mainstream (T:M) ratios), but not in central confluences (low T:M ratios). Thus, effects of small tributaries on receiving mainstreams are dependent on the T:M ratio.

scholarly journals Composition and structure of fish assemblage from Passa Cinco stream, Corumbataí river sub-basin, SP, Brazil

2012 ◽  
Vol 72 (1) ◽  
pp. 87-96
Author(s):  
AL Carmassi ◽  
G Rondineli ◽  
FC Ferreira ◽  
FMS Braga
Keyword(s):  
Species Distribution ◽  
Fish Assemblage ◽  
Altitudinal Gradient ◽  
Habitat Diversity ◽  
Important Species ◽  
Assemblage Composition ◽  
Gill Nets ◽  
Composition And Structure ◽  
Significant Difference ◽  
Richness Index

The aim of this work was to determine the composition of the fish assemblage of Passa Cinco stream and verify changes in their structure on the altitudinal gradient. Six samples were performed at five different sites in Passa Cinco stream (from the headwater, at order two, to its mouth, at order six), using an electric fishery equipment and gill nets in May, July, September and November of 2005 and January and March of 2006. The indices of Shannon's diversity, Pielou's evenness and Margalef's richness were quantified separately considering the different fishery equipment (nets versus electric fishery equipment). An ANOVA was used to compare samples collected in relation to values of abundance, diversity, evenness and richness. The representativeness of the species was summarised by their average values of abundance and weight. We captured 5082 individuals distributed into 61 species. We observed a trend of increasing diversity, richness and evenness of species from site 1 to 3, with further decrease in sites 4 and 5. The values found for habitat diversity also followed this pattern. Significant differences were found for all three indices considering the electric fishery samples. For individuals caught with nets, only the richness index showed a significant difference. Characidium aff. zebra was an important species in the headwater and transition sites and Hypostomus strigaticeps in middle-lower course sites. Despite the small extension of the Passa Cinco stream, environments structurally well defined were evidenced by the species distribution and assemblage composition along the gradient.

Species and genus richness and assemblage composition of stream caddisflies (Insecta: Trichoptera) vary with latitude in mountain rainforest of Argentina

2019 ◽  
Vol 70 (5) ◽  
pp. 687
Author(s):  
Edgardo J. I. Pero ◽  
Paola A. Rueda Martín ◽  
María C. Reynaga
Keyword(s):  
Latitudinal Gradient ◽  
Aquatic Insect ◽  
Latitudinal Gradients ◽  
Mountain Forest ◽  
Low Latitude ◽  
Study Region ◽  
Assemblage Composition ◽  
Composition And Structure ◽  
Genus Richness ◽  
Rank Abundance

Evidence found in results of studies of latitudinal gradients of benthic macroinvertebrate diversity is variable. This study analysed how species and genus richness and the composition of caddisfly assemblages (Insecta: Trichoptera) vary in Argentinean mountain forest through a latitudinal gradient from 22 to 28°S. Qualitative and quantitative data from 20 stream sites were compared. Assemblage richness and composition were analysed by comparing linear regressions, rank–abundance (RA) curves and non-metric multidimensional scaling (nMDS). Taxonomic richness increased from high to low latitude. RA curves showed changes in assemblage composition and structure across the latitudinal gradient. The nMDS revealed that the composition of the assemblages also changed along the latitudinal gradient. The patterns are similar to those observed in plants and vertebrates from the study region. The results are of particular note because a latitudinal gradient of aquatic insect diversity has rarely been observed in a narrow range.

scholarly journals Drainage Network Analysis and Structuring of Topologically Noisy Vector Stream Data

2019 ◽  
Vol 8 (9) ◽  
pp. 422
Author(s):  
John B. Lindsay ◽  
Wanhong Yang ◽  
Duncan D. Hornby
Keyword(s):  
Network Analysis ◽  
Channel Length ◽  
Drainage Network ◽  
Stream Networks ◽  
Stream Data ◽  
Suitable Alternative ◽  
Analysis Technique ◽  
Digital Elevation ◽  
Topological Errors ◽  
Fine Resolution

Drainage network analysis includes several operations that quantify the topological organization of stream networks. Network analysis operations are frequently performed on streams that are derived from digital elevation models (DEMs). While these methods are suited to application with fine-resolution DEM data, this is not the case for coarse DEMs or low-relief landscapes. In these cases, network analysis that is based on mapped vector streams is an alternative. This study presents a novel vector drainage network analysis technique for performing stream ordering, basin tagging, the identification of main stems and tributaries, and the calculation of total upstream channel length and distance to outlet. The algorithm uses a method for automatically identifying outlet nodes and for determining the upstream-downstream connections among links within vector stream networks while using the priority-flood method. The new algorithm was applied to test stream datasets in two Canadian study areas. The tests demonstrated that the new algorithm could efficiently process large hydrographic layers containing a variety of topological errors. The approach handled topological errors in the hydrography data that have challenged previous methods, including disjoint links, conjoined channels, and heterogeneity in the digitized direction of links. The method can provide a suitable alternative to DEM-based approaches to drainage network analysis, particularly in applications where stream burning would otherwise be necessary.

Mayfly (Ephemeroptera) assemblages of a Pannonian lowland mountain, with first records of the parasite Symbiocladius rhithrogenae (Zavrel, 1924) (Diptera: Chironomidae)

2018 ◽  
Vol 54 ◽  
pp. 31
Author(s):  
Marina Vilenica ◽  
Viktorija Ergović ◽  
Zlatko Mihaljević
Keyword(s):  
Aquatic Insects ◽  
Sampling Period ◽  
East Europe ◽  
Assemblage Composition ◽  
East European ◽  
South East Europe ◽  
Nmds Analysis ◽  
Baetis Rhodani ◽  
Ephemera Danica ◽  
Chironomid Fauna

Despite increasing numbers of studies on aquatic insects in South-East European streams, there are still gaps in the knowledge about their distribution and assemblage composition in many regions. As one of the most abundant and sensitive aquatic insects, mayflies are widely used as bioindicator taxa. With the main goal of improving the knowledge of South-East European mayflies, a study was conducted of 15 streams along a Pannonian lowland mountain, in spring and summer 2017. A total of 18 mayfly taxa were recorded, where Ephemera danica Müller, 1764 and Baetis rhodani (Pictet, 1843) were the most widespread. All sites were characterized with the domination of rhithral elements, with similar shares of grazers/scrapers and detritivores. Nevertheless, sites at lower altitudes generally had a higher share of potamal and littoral elements, and a higher share of detritivores than at higher altitudes. NMDS analysis separated sites mainly based on sampling period. Although Heptageniidae nymphs were recorded in all streams, the parasitic chironomid Symbiocladius rhithrogenae (Zavrel, 1924) was recorded attached to three nymphs of Rhithrogena group semicolorata, each in a different stream. These records represent the first report of this species for Croatia. The current study contributes significantly to our knowledge of mayfly assemblages and species distribution in South-East Europe. Moreover, with a newly recorded species, this study indicates that the knowledge of the Croatian chironomid fauna is still growing.

scholarly journals Incorporating lakes in stream fish habitat models: are we missing a key landscape attribute?

2017 ◽  
Vol 74 (5) ◽  
pp. 629-635 ◽  
Author(s):  
Marc Pépino ◽  
Marco A. Rodríguez ◽  
Pierre Magnan
Keyword(s):  
Relative Abundance ◽  
Brook Trout ◽  
Environmental Variability ◽  
Fish Habitat ◽  
Stream Fish ◽  
Drainage Network ◽  
Stream Networks ◽  
Stream Network ◽  
Habitat Models ◽  
Critical Attribute

Although lakes and rivers are intimately connected, more effort is needed to develop conceptual approaches accounting for lake–stream interactions within the drainage network. Lakes can buffer the impacts of environmental variability in streams and facilitate stream fish recolonization processes. However, lakes have rarely been incorporated in habitat models for stream fish. We examine whether including the presence of lakes in habitat models can improve our understanding of brook trout (Salvelinus fontinalis) abundance in streams. We quantified brook trout relative abundance in 36 streams over 3 consecutive years by single-pass electrofishing. Relative abundance of brook trout in streams was greatest when lakes were present in the stream network. Lakes had greater influence on relative abundance in headwater streams than in larger streams. These results emphasize the importance of considering lakes as a critical attribute in landscape fish habitat models, many of which focus on terrestrial landscape variables. We discuss potential gains from incorporating the presence of lakes in (i) multiscale habitat models, (ii) analyses of spatiotemporal distribution of thermal refuges, and (iii) metrics of habitat connectivity in lake–stream networks.

scholarly journals Fishes and Macroinvertebrates of Padawan Limestone, Sarawak, Malaysia

1970 ◽  
Vol 3 (2) ◽  
pp. 1-14
Author(s):  
Jongkar Grinang
Keyword(s):  
Aquatic Insects ◽  
Food Source ◽  
Northern Region ◽  
Conservation Value ◽  
International Union ◽  
Red Lists ◽  
Aquatic Fauna ◽  
East Malaysia ◽  
High Conservation ◽  
Total Species

A survey on fishes and macroinvertebrates was conducted at four streams and a cave passage in the Padawanlimestone area of Sarawak, East Malaysia (Borneo). Eighty-four species, comprising 21 fishes, seven crabs,four prawns, 10 snails and 42 aquatic insects were recorded. The finding adds the total species of fishes andcrustaceans known from limestone areas in Sarawak to 79 and 29, respectively. Padawan limestone has asimilar aquatic fauna with Bau limestone area. Both areas have different species composition from limestonehabitats in the northern region of Sarawak. Padawan limestone area has high conservation value, supporting anumber of endemic and threatened species, including seven crab and six fish species. Two species of semiterrestrialcrabs, Stygothelphusa bidiense and Terrathelphusa kuchingensis are listed as Vulnerable andEndangered, respectively, by the International Union for the Conservation of Nature Red Lists. It was alsonoted that fishes and a few species of snails serve as important supplement food source for local communitiesliving in the area.

scholarly journals Chironomidae (Insecta: Diptera) of different habitats and microhabitats of the Vacacai-Mirim River microbasin, Southern Brazil

2013 ◽  
Vol 85 (3) ◽  
pp. 975-985 ◽  
Author(s):  
RODRIGO KONIG ◽  
SANDRO SANTOS
Keyword(s):  
Community Composition ◽  
Aquatic Insects ◽  
Diversity Index ◽  
Taxonomic Richness ◽  
Anthropogenic Pressures ◽  
Multivariate Statistical ◽  
Chironomid Larvae ◽  
Composition And Structure ◽  
Chemical Conditions ◽  
Physical And Chemical

The Chironomidae family is one of the main groups of aquatic insects present in streams. This work aimed to investigate the influences of anthropogenic pressures and substrate types on chironomid community composition and structure. Chironomid larvae were collected during the summer of 2007 at four sites along the Vacacaí-Mirim River microbasin, chosen based on the different available benthic substrates. The organisms were identified in the laboratory at the genus level, and the density, the rarefied taxonomic richness and the Shannon diversity index were calculated. The faunal structure was subjected to an ANOVA to compare the metrics among sites and substrates. The community composition of the sites was subjected to a multivariate statistical analysis. Differences in the composition, richness, density, and diversity were observed among the sites due to differences in the levels of nutrients and solids generated by the presence of crops close to water bodies. Samples collected from sandy substrates exhibited a lower density and taxonomic richness because sand is a poorer substrate than the others that were sampled. In organic or mixed substrates with higher energy availability and better shelter conditions, the observed densities were higher. The physical and chemical conditions and the morphometric characteristics of the sites were more influential than the substrates.

Anisops sardeus (Heteroptera): A new expansive species in Central Europe

Biologia ◽  
2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Barbora Klementová ◽  
Marek Svitok
Keyword(s):  
Alien Species ◽  
Central Europe ◽  
Current Distribution ◽  
Range Expansion ◽  
Aquatic Insects ◽  
Aquatic Insect ◽  
First Record ◽  
Insect Species ◽  
Aquatic Fauna

AbstractAlthough insects form a large part of the aquatic fauna worldwide, expansive species of aquatic insects are quite rare. Recently, we can observe a tendency to the range expansions in several aquatic insect species. Here, we present the first record of water bug species Anisops sardeus sardeus (Heteroptera: Notonectidae) from Slovakia. This is the northernmost record of this small-bodied backswimmer which is native to Sahelo-Sindian area, extending to Mediterranean. However, the species shows recent range expansion northward in Europe. We document the current distribution of A. s. sardeus in Slovakia and Europe, and discuss the drivers of expansion and possible impact of the alien species on resident fauna.

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