scholarly journals Effects of experimental multi-season drought on abundance, richness, and beta diversity patterns in perennially flowing stream insect communities

Hydrobiologia ◽  
2021 ◽  
Author(s):  
P. Saffarinia ◽  
K. E. Anderson ◽  
D. B. Herbst
Keyword(s):  
Beta Diversity ◽  
Aquatic Insect ◽  
Flow Regimes ◽  
Surface Flow ◽  
Insect Community ◽  
Stream Channels ◽  
Insect Communities ◽  
Threshold Response ◽  
Small Streams ◽  
Flow Loss

AbstractFreshwater systems are projected to experience increased hydrologic extremes under climate change. To determine how small streams may be impacted by shifts in flow regimes, we experimentally simulated flow loss over the span of three summers in nine 50 m naturally fed stream channels. The aquatic insect community of these streams was sampled before, during, and after experimental drought treatments as well as following one unforeseen flood event. Abundance, richness, and beta diversity were measured as indicators of biotic effects of altered flow regimes. Abundance declined in proportion to flow loss. In contrast, we observed a threshold response in richness where richness did not decrease except in channels where losses of surface flow occurred and disconnected pools remained. The flood reset this pattern, but communities continued their prior trajectories shortly thereafter. Beta diversity partitions suggested no strong compositional shifts, and that the effect of drought was largely experienced uniformly across taxa until flow cessation. Pools served as a refuge, maintaining stable abundance gradients and higher richness longer than riffles. Upon flow resumption, abundance and richness returned to pre-treatment levels within one year. Our results suggest that many taxa present were resistant to drought conditions until loss in surface flow occurred.

Spatial and seasonal variability of emergent aquatic insects and nearshore spiders in a subtropical estuary

2019 ◽  
Vol 70 (4) ◽  
pp. 541 ◽  
Author(s):  
Martha J. Zapata ◽  
S. Mažeika P. Sullivan
Keyword(s):  
Aquatic Insects ◽  
High Salinity ◽  
Aquatic Insect ◽  
Freshwater Ecosystems ◽  
Dispersal Ability ◽  
Insect Community ◽  
Insect Communities ◽  
Low Salinity ◽  
Subtropical Estuary ◽  
Adult Aquatic Insects

Variability in the density and distribution of adult aquatic insects is an important factor mediating aquatic-to-terrestrial nutritional subsidies in freshwater ecosystems, yet less is understood about insect-facilitated subsidy dynamics in estuaries. We surveyed emergent (i.e. adult) aquatic insects and nearshore orb-weaving spiders of the families Tetragnathidae and Araneidae in a subtropical estuary of Florida (USA). Emergent insect community composition varied seasonally and spatially; densities were lower at high- than low-salinity sites. At high-salinity sites, emergent insects exhibited lower dispersal ability and a higher prevalence of univoltinism than low- and mid-salinity assemblages. Orb-weaving spider density most strongly tracked emergent insect density rates at low- and mid-salinity sites. Tetragnatha body condition was 96% higher at high-salinity sites than at low-salinity sites. Our findings contribute to our understanding of aquatic insect communities in estuarine ecosystems and indicate that aquatic insects may provide important nutritional subsidies to riparian consumers despite their depressed abundance and diversity compared with freshwater ecosystems.

How does the management of rice in natural ponds alter aquatic insect community functional structure?

2016 ◽  
Vol 67 (11) ◽  
pp. 1644 ◽  
Author(s):  
Marina S. Dalzochio ◽  
Renata Baldin ◽  
Cristina Stenert ◽  
Leonardo Maltchik
Keyword(s):  
Functional Divergence ◽  
Aquatic Insect ◽  
Functional Redundancy ◽  
Rice Fields ◽  
Functional Composition ◽  
Insect Community ◽  
Insect Communities ◽  
Conventional Agriculture ◽  
Organic Rice ◽  
Functional Richness

Changes to biodiversity have mainly been assessed using taxonomic diversity indices. Although these approaches contribute to our scientific understanding of species richness and composition patterns, trait-based metrics may be more useful for detecting responses to land-use change. We compared functional diversity of aquatic insect communities along a gradient of agricultural intensification. Our goal was to compare functional redundancy, functional richness, functional evenness and functional divergence among natural ponds, and organic and conventional rice fields. We recorded 15606 aquatic insects distributed across 61 genera. The highest functional redundancy and richness were observed in the natural ponds, followed by organic rice fields and conventional ones. The functional composition varied among natural ponds and rice fields, and differed between organic and conventional rice fields. Organic management favoured the establishment of some pond insect traits, such as predatory taxa, in rice agroecosystems. Our analysis suggests that the conversion of ponds to rice fields results in a shift to less specialised aquatic insect communities with altered functional composition groups. Nevertheless, this result should not be seen as a negative reflection on organic rice fields, because organic rice production affords a better compromise between agricultural production and ecosystem function than conventional agriculture.

scholarly journals Contrasting beta diversity and functional composition of aquatic insect communities across local to regional scales in Amazonian streams

2020 ◽  
Author(s):  
Gilberto Nicacio ◽  
Erlane José Cunha ◽  
Neusa Hamada ◽  
Leandro Juen
Keyword(s):  
Beta Diversity ◽  
Geographic Distance ◽  
Aquatic Insect ◽  
Procrustes Analysis ◽  
Functional Composition ◽  
Species Replacement ◽  
Environmental Predictors ◽  
Insect Communities ◽  
Trait Convergence ◽  
Community Dissimilarity

AbstractWe investigated how components of beta diversity (i.e., the turnover and nestedness and functional compositional) aquatic insect assemblages change among sites and are influenced by environmental and spatial drivers. For this, we analyzed beta-diversity and functional composition of Ephemeroptera, Plecoptera, and Trichoptera in 16 streams in two Amazonian basins with distinct environmental conditions (the Carajás and Tapajós regions). We performed Multiple regression on dissimilarity matrices (MRM) and Procrustes analysis to test spatial and environmental influences on the taxonomic and functional composition of communities. Community dissimilarity was most related to variations in geographic distance and topography, which highlighted the environmental distances shaping the communities. Variation in functional composition could be mostly attributed to the replacement of species by those with similar traits, indicating trait convergence among communities. Environmental predictors best-explained species replacement and trait congruence within and between the regions evaluated. In summary, among communities with different taxonomic compositions, the high species replacement observed appears to be leading them to have similar community structure, with species having the same functional composition, even in communities separated by both small and large geographic distances.

Cave benthic invertebrates in south-eastern Brazil: are there 'key' factors structuring such communities?

2018 ◽  
Vol 69 (11) ◽  
pp. 1762 ◽  
Author(s):  
T. G. Pellegrini ◽  
P. S. Pompeu ◽  
R. L. Ferreira
Keyword(s):  
Aquatic Insect ◽  
Physicochemical Characteristics ◽  
Hydraulic Characteristics ◽  
Key Factors ◽  
Stream Channels ◽  
Insect Communities ◽  
Eastern Brazil ◽  
Physical Features ◽  
Local Variability ◽  
Insect Assemblage

The aim of this study was to determine the effects of microhabitat traits related to water quality and physical features of stream channels (substrate, channel morphology and hydraulic characteristics) on the richness and structure of the aquatic insect assemblage in cave streams. Sampling was conducted in three subterranean streams in Brazil. Aquatic insect richness was significantly and positively related to water depth and the presence of shelters for invertebrates. These shelters are directly related to channel heterogeneity, a factor that determined the surface area of habitats suitable for colonisation, refuges and the amount and variety of nutrients in streams where resources are extremely limited. Furthermore, analyses of community composition revealed that aquatic insect assemblages in each cave were structured by distinct factors (including physicochemical characteristics of the water or hydraulic features of the channel). Together, these findings highlight that different factors are responsible for structuring the assemblages in each cave, which may reflect their local variability, and that silting of cave streams would likely have deleterious effects on aquatic insect communities through reductions in overall habitat heterogeneity.

scholarly journals The rainy season increases the abundance and richness of the aquatic insect community in a Neotropical reservoir

2015 ◽  
Vol 75 (1) ◽  
pp. 144-151 ◽  
Author(s):  
HS Santana ◽  
LCF Silva ◽  
CL. Pereira ◽  
J. Simião-Ferreira ◽  
R. Angelini
Keyword(s):  
Beta Diversity ◽  
Rainy Season ◽  
Aquatic Insect ◽  
Habitat Diversity ◽  
Water Levels ◽  
Insect Community ◽  
Insect Larvae ◽  
Dry Period ◽  
Pearson Correlations ◽  
Material Input

Alterations in aquatic systems and changes in water levels, whether due to rains or dam-mediated control can cause changes in community structure, forcing the community to readjust to the new environment. This study tested the hypothesis that there is an increase in the richness and abundance of aquatic insects during the rainy season in the Serra da Mesa Reservoir, with the premise that increasing the reservoir level provides greater external material input and habitat diversity, and, therefore, conditions that promote colonization by more species. We used the paired t test to test the differences in richness, beta diversity, and abundance, and a Non-metric Multidimensional Scaling (NMDS) was performed to identify patterns in the community under study. Additionally, Pearson correlations were analyzed between the richness, abundance, and beta diversity and the level of the reservoir. We collected 35,028 aquatic insect larvae (9,513 in dry period and 25,515 in the rainy season), predominantly of the Chironomidae family, followed by orders Ephemeroptera, Trichoptera, and Odonata. Among the 33 families collected, only 12 occurred in the dry season, while all occurred in the rainy season. These families are common in lentic environments, and the dominance of Chironomidae was associated with its fast colonization, their behavior of living at high densities and the great tolerance to low levels of oxygen in the environment. The hypothesis was confirmed, as the richness, beta diversity, and abundance were positively affected by the increase in water levels due to the rainy season, which most likely led to greater external material input, greater heterogeneity of habitat, and better conditions for colonization by several families.

Behavioral Responses of Drunella coloradensis (Ephemeroptera) Nymphs to Short-Term pH Reductions

1993 ◽  
Vol 50 (12) ◽  
pp. 2692-2697 ◽  
Author(s):  
Christopher M. Pennuto ◽  
Frank deNoyelies Jr.
Keyword(s):  
Acute Stress ◽  
Aquatic Insect ◽  
Behavioral Responses ◽  
Activity Levels ◽  
Stream Channels ◽  
Insect Communities ◽  
Stream Insects ◽  
Community Monitoring ◽  
Behavior Frequency ◽  
Passive Drift

Behavioral responses of Drunella coloradensis nymphs were examined in outdoor experimental stream channels after pH reductions of 1 and 2 pH units below ambient. The severity of pH decline below the ambient of 7.8 influenced the behavior patterns displayed by nymphs. At pH 7.01 (an intermediate pH decline) nymphs sat less frequently and burrowed more than controls. Burrowing behavior frequency returned to control levels and drifting and crawling behaviors increased relative to controls at pH 6.02. Ventilatory behaviors increased with pH decline, but were independent of the severity of acidity increases. These results suggest that individual behaviors may offer a more sensitive indicator of sub-acute stress in aquatic insect communities than population or community monitoring. Behaviors leading to increased activity levels in stream insects may have community-level effects via changes in predator–prey encounter rates or increased susceptibility to passive drift. These potential changes are discussed in reference to monitoring for acidification effects.

Corrigendum to: Spatial and seasonal variability of emergent aquatic insects and nearshore spiders in a subtropical estuary

2019 ◽  
Vol 70 (4) ◽  
pp. 609
Author(s):  
Martha J. Zapata ◽  
S. Mažeika P. Sullivan
Keyword(s):  
Aquatic Insects ◽  
High Salinity ◽  
Aquatic Insect ◽  
Freshwater Ecosystems ◽  
Dispersal Ability ◽  
Insect Community ◽  
Insect Communities ◽  
Low Salinity ◽  
Subtropical Estuary ◽  
Adult Aquatic Insects

Variability in the density and distribution of adult aquatic insects is an important factor mediating aquatic-to-terrestrial nutritional subsidies in freshwater ecosystems, yet less is understood about insect-facilitated subsidy dynamics in estuaries. We surveyed emergent (i.e. adult) aquatic insects and nearshore orb-weaving spiders of the families Tetragnathidae and Araneidae in a subtropical estuary of Florida (USA). Emergent insect community composition varied seasonally and spatially; densities were lower at high- than low-salinity sites. At high-salinity sites, emergent insects exhibited lower dispersal ability and a higher prevalence of univoltinism than low- and mid-salinity assemblages. Orb-weaving spider density most strongly tracked emergent insect density rates at low- and mid-salinity sites. Tetragnatha body condition was 96% higher at high-salinity sites than at low-salinity sites. Our findings contribute to our understanding of aquatic insect communities in estuarine ecosystems and indicate that aquatic insects may provide important nutritional subsidies to riparian consumers despite their depressed abundance and diversity compared with freshwater ecosystems.

Taxonomic sufficiency and effects of environmental and spatial drivers on aquatic insect community

2019 ◽  
Vol 107 ◽  
pp. 105624
Author(s):  
B.S. Godoy ◽  
A.P.J. Faria ◽  
L. Juen ◽  
L. Sara ◽  
L.G. Oliveira
Keyword(s):  
Aquatic Insect ◽  
Insect Community ◽  
Taxonomic Sufficiency

Flow and Energy Loss Downstream of Rectangular Sharp-Crested Weirs for Free and Submerged Flows

2021 ◽  
Author(s):  
Mahmud R. Amin ◽  
Nallamuthu Rajaratnam ◽  
David Z. Zhu
Keyword(s):  
Energy Loss ◽  
Flow Regime ◽  
Analytical Study ◽  
Flow Characteristics ◽  
Turbulent Jets ◽  
Flow Regimes ◽  
Impinging Jet ◽  
Relative Energy ◽  
Surface Flow ◽  
Upper Stage

Abstract This work presents an analytical study of the flow and energy loss immediately downstream of rectangular sharp-crested weirs for free and submerged flows, using the theory of plane turbulent jets and the analysis of some relevant studies. The flow regimes downstream of the sharp-crested weir is characterized as the impinging jet and surface flow regimes. Based on the flow characteristics and the downstream tailwater depths, each flow regime is further classified, and the relative energy loss equation is developed. It is found that significant energy loss occurs for the regime of supercritical flow and the upper stage of impinging jet flow. The energy loss for the submerged flow regime is minimal.

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