Rarefied Richness Research Articles

Fish diversity, assemblage pattern along with the environmental variables in tidal fresh water stretch in the Hooghly estuary of Gangetic delta, West Bengal, India

The greatest estuary created by the Gangetic delta in India is the Hooghly estuary. Despite their importance to the estuarine biodiversity, the tidal freshwater areas of this estuary have gained little interest from ecologists. Present study aims to explore the fish diversity with its assemblage pattern and their relationship with physico-chemical parameters from June 2020 to May 2021. There have been identified 118 fish species in total, from 14 orders and 47 families, with seven (7) being near threatened, fifteen (15) vulnerable, four (4) endangered, and eight (8) not evaluated. Perciformes (29.66 %), Cypriniformes (22.88 %), and Siluriformes (21.18 %) accounted for 73.72 % of the overall species count. Station-1 has significantly higher species richness, rarefied richness, and abundance. Station-3 and station-2 followed station-1 respectively. The composition of fish species changed significantly among the stations, as shown by cluster analysis, nMDS (nonmetric multidimensional scaling), ANOSIM (analysis of similarities), and SIMPER (similarity percentage analysis) (p <0.05). The canonical correspondence analysis revealed that alkalinity, conductivity, phosphate, and total carbon dioxide of the water were the key environmental parameters. In addition to defining a sustainable management method for the fish resources in the Hooghly estuary, this effort will act as a baseline study for further investigation.

Long-term changes and seasonal variability in the stream macrofauna of a Himalayan river system

Interpreting long-term variability in mountain stream ecosystems is challenging where potential causes such as climate change and altered land-use act simultaneously. The scarcity of historical data also limits research opportunity, especially at low latitudes. Here we assess the macroinvertebrate fauna of 12 Himalayan streams in Nepal covering an altitudinal gradient from 1500 to 3900 m asl using data from 1992, 2022 and 2023. We aimed to: 1) compare long-term change in richness and community composition over three decades to short-term seasonal variation, and 2) analyse long-term changes in relation to catchment properties. Rarefied richness decreased equally with altitude in 1992 and 2022, but was greater at most sites in 2022, with several new families detected. In contrast, no clear seasonal pattern was found. The 2022:1992 ratio in rarefied richness was positively correlated with catchment area and weakly with maximum catchment altitude, while the two highest and glaciated sites gained relatively more taxa than other sites. NMDS ordinations from rarefied Bray-Curtis dissimilarities showed considerable overlap in communities among the three datasets. Pairwise rarefied dissimilarities among all sites increased significantly with altitudinal distance between sites in 1992 while there was no such relationship in 2022. Dissimilarities between 1992 and 2022 samples showed a near-significant correlation with increased catchment vegetation cover as shown by NDVI. Our study is the first to document long-term variations in stream macroinvertebrate communities in Himalayan mountain streams, illustrating how some altitudinal patterns have remained stable through time while others appear to have weakened with links to global change.

Lessons learned from an interdisciplinary evaluation of long-term restoration outcomes on 37 restored coastal grasslands in California

Governmental and non-governmental organizations spend considerable funding on restoring ecosystems to counter biodiversity loss, yet outcomes are often not assessed at a regional scale. Monitoring is done ≤5 years after project-implementation, if at all, and rarely assesses the effects of management practices on project success. We combined vegetation surveys and management interviews to compare long-term restoration outcomes of 37 California coastal grassland projects (5–33 y post-implementation) that spanned a 1000-km north-south gradient. We found that coastal grassland restoration is largely successful at reaching project goals (95 %) and a standard performance metric (80 %) to restore native cover, but land managers preferentially use a small number of well-tested, “high success” species, potentially at the expense of regional diversity. Medium and high maintenance intensity resulted in lower non-native cover and improved native cover and rarefied native richness. Managers of voluntary (non-statutory) sites were more open to assessing outcomes and spent less per hectare compared to legally mandated (statutory) projects but achieved similar plant cover and even higher rarefied richness. Statutory project managers indicated that regulatory agencies sometimes lowered compliance goals for native cover if the initial targets were not met. Additional funding for greater maintenance intensity and incorporating more locally distinctive species (i.e., endemic or range-restricted) may help counteract potential unintended consequences from preferential plant selection, and inter-agency coordination of species selection could reduce biotic homogenization. We recommend delegating funds to a third-party monitoring group to ensure legally mandated compliance and consistency in assessment.

Variability in nearshore fish biodiversity indicators after a mining disaster in eastern Brazil

The rupture of the Fundão mining dam (Doce river basin, Brazil) caused a wide range of negative impacts. Yet, assemblage-level implications to estuarine and coastal fishes remain unclear, partly due to the lack of pre-disaster information. Based on monthly otter trawl surveys, we analyzed spatial and seasonal variability in univariate (total biomass, biomass of species vulnerable to exploitation, rarefied richness and evenness) and multivariate (species composition and trophic composition) indicators of fish biodiversity in the Doce river delta, eastern Brazil. We determined the independent and interactive effects of environmental, seasonal and spatial variables on species composition to test whether environmental alterations provoked by mine tailings could affect assemblage's organization. Most indicators present idiosyncratic spatiotemporal patterns, suggesting they have complementary roles in revealing changes in fish biodiversity. Environmental variables, including those affected by the Fundão dam collapse such as turbidity, dissolved oxygen and pH, were much more important than seasonal and spatial predictors in explaining the variation in fish species composition. These findings highlight the potential from mine tailings to disrupt local ichthyofauna and indicate a preponderant role of environmental conditions in assemblage structuring. Given the lack of data prior to rupture, our results may be used as a baseline against which to assess temporal trends in fish biodiversity relative to changes detected in less disturbed estuarine and coastal assemblages.

Weak population spatial genetic structure and low infraspecific specificity for fungal partners in the rare mycoheterotrophic orchid Epipogium aphyllum

Some plants abandoned photosynthesis and developed full dependency on fungi for nutrition. Most of the so-called mycoheterotrophic plants exhibit high specificity towards their fungal partners. We tested whether natural rarity of mycoheterotrophic plants and usual small and fluctuating population size make their populations more prone to genetic differentiation caused by restricted gene flow and/or genetic drift. We also tested whether these genetic characteristics might in turn shape divergent fungal preferences. We studied the mycoheterotrophic orchid Epipogium aphyllum, addressing the joint issues of genetic structure of its populations over Europe and possible consequences for mycorrhizal specificity within the associated fungal taxa. Out of 27 sampled E. aphyllum populations, nine were included for genetic diversity assessment using nine nuclear microsatellites and plastid DNA. Population genetic structure was inferred based on the total number of populations. Individuals from 17 locations were included into analysis of genetic identity of mycorrhizal fungi of E. aphyllum based on barcoding by nuclear ribosomal DNA. Epipogium aphyllum populations revealed high genetic diversity (uHe = 0.562) and low genetic differentiation over vast distances (FST = 0.106 for nuclear microsatellites and FST = 0.156 for plastid DNA). Bayesian clustering analyses identified only two genetic clusters, with a high degree of admixture. Epipogium aphyllum genets arise from panmixia and display locally variable, but relatively high production of ramets, as shown by a low value of rarefied genotypic richness (Rr = 0.265). Epipogium aphyllum genotype control over partner selection was negligible as (1) we found ramets from a single genetic individual associated with up to 68% of the known Inocybe spp. associating with the plant species, (2) and partner identity did not show any geographic structure. The absence of mosaicism in the mycorrhizal specificity over Europe may be linked to preferential allogamous habit of E. aphyllum and significant gene flow, which tend to promote host generalism.

Preservation of sedimentary plant DNA is related to lake water chemistry

AbstractLittle is currently known about preservation of plant DNA in lake sediments. Most prior information originates from laboratory experiments while systematic field‐based studies are still lacking. Here, we used the “g” and “h” universal primers for the P6 loop region of the chloroplast trnL (UAA) intron to amplify plant DNA from 219 lake surface sediments from China and Siberia. We introduce (i) the percentage of sequence counts with the best identity ≥95%, (ii) weighted average identity, (iii) weighted average DNA fragment length, and iv) rarefied richness of terrestrial seed plants of plant DNA metabarcoding as proxies for sedimentary DNA preservation and relate them to five environmental variables (lake water conductivity, lake water pH, mean July air temperature, and sampling depth, lake size) using boosted regression tree (BRT) analyses. Our results suggest that lake water chemical characteristics, that is, electrical conductivity and pH, are the most important variables for the preservation of plant DNA in lake sediments. Intermediate water conductivities (100–500 μS cm−1) and neutral to slightly alkaline water pH (7–9) may facilitate plant DNA preservation. Furthermore, deep lakes seem to support plant DNA preservation as indicated by relatively high rarefied richness. We also find high rarefied richness in small lakes compared with large lakes, but this result needs to be assessed by more studies in the future. None of our BRT models shows that mean July air temperature is a key variable to limit plant DNA preservation. To conclude, our results suggest that sedimentary DNA studies can preferentially select deep lakes characterized by intermediate water conductivities and neutral to slightly alkaline pH conditions.

Pollinator sampling methods influence community patterns assessments by capturing species with different traits and at different abundances

In order to synthesize changes in pollinating insect communities across space and time, it is necessary to understand whether, and how, sampling methods influence assessments of community patterns. We compared how two common sampling methods—yellow combined flight traps and net sampling—influence our understanding of the species richness, abundance and composition of wild bees and hoverflies, and addressed whether these patterns resulted from potentially biased sampling of individuals or species with different types of functional traits. We sampled bee and hoverfly communities in six sites over three seasons in Saxony-Anhalt, Germany. We captured more species and individuals of bees with traps and more species and individuals of hoverflies with net sampling. However, rarefied richness results were less dramatic between the sampling methods for bees and were not different between the sampling methods for hoverflies. Thus, differences in species richness across sampling methods were mostly due to differences in the number of individuals captured in the different methods. We captured more small-sized bees and hoverflies with traps. We tested if the different methods collected individuals and species with different functional traits, such as nesting preferences, sociality and flower specialization for bees and floral preference, migratory status and habitat preference for hoverflies. For most traits, we collected more individuals but not more species with a certain trait in the different methods. This was mainly due to a high abundance of one species being collected in the different methods. These results suggest that the best methodology depends on the aim of the survey, and that the methods cannot be easily combined into synthesis research. Our results have implications for the development of monitoring schemes for pollinators and for synthesis of trends that can identify threats to pollinators and inform research of pollinator conservation strategies.

A Pilot Study on the Microbiome of Amblyomma hebraeum Tick Stages Infected and Non-Infected with Rickettsia africae.

Variation in tick microbiota may affect pathogen acquisition and transmission but for many vector species, including Amblyomma hebraeum, components and determinants of the microbiome are unidentified. This pilot study aimed to determine baseline microbial community within A. hebraeum nymphs infected- and non-infected with Rickettsia africae from the environment, and within adult ticks infected- and non-infected with R. africae collected from cattle sampled from two locations in the Eastern Cape province of South Africa. Adult A. hebraeum ticks (N = 13) and A. hebraeum nymph (N = 15) preliminary screened for R. africae were randomly selected and subjected to Illumina sequencing targeting the v3–v4 hypervariable regions of the 16S rRNA gene. No significant difference in microbial community composition, as well as rarefied OTU richness and diversity were detected between adults and nymphs. Nymphs showed a higher richness of bacterial taxa indicating blood-feeding could have resulted in loss of microbial diversity during the moulting stage from nymph to adult. Core OTUs that were in at least 50% of nymphs and adults negative and positive for Rickettsia at 1% minimum relative abundance were Rickettsia, Coxiella and Ruminococcaceae UCG-005 with a single genus Arsenophonus occurring only in nymphs negative for Rickettsia. Ehrlichia spp. was present in only four nymphal ticks positive for Rickettsia. Interestingly, Rickettsia aeschlimannii was found in one nymph and one adult, indicating the first ever detection of the species in A. hebraeum. Furthermore, A. hebraeum harboured a Coxiella-like endosymbiont, which should be investigated further as Coxiella may affect the viability and transmission of other organisms.

Carabid beetle (Coleoptera, Carabidae) richness, diversity, and community structure in the understory of temporarily flooded and non-flooded Amazonian forests of Ecuador.

Although tropical regions harbor the greatest arthropod diversity on Earth, the majority of species are taxonomically and scientifically unknown. Furthermore, how they are organized into functional communities and distributed among habitats is mostly unstudied. Here we examine species richness, diversity, and community composition of carabid beetles (Coleoptera: Carabidae) and compare them between flooded (FP) and non-flooded terra firme (TF) forests in the Yasuní area of Ecuador. The forest understory was sampled using flight intercept traps (FITs) and systematic hand collections at night in June and July 2011 and 2012, and FITs in October and November 2011. A total of 1,255 Carabidae representing 20 tribes, 54 genera, and 143 morphospecies was collected. Mean number of individuals and mean species richness did not differ significantly between FP and TF; however, numbers of Cicindelini (tiger beetles) and Pentagonicini were higher in TF forest while numbers of Lachnophorini and Scaritini were higher in FP forest. Overall, FP had significantly higher rarefied richness but extrapolation of rarefaction curves using the Chao1 nonparametric diversity estimator show that this difference may decrease with additional sampling. The inverse Simpson index was significantly higher for FP than TF forest. Nonmetric multidimensional scaling (NMDS) ordination and dissimilarity coefficient values show that FP and TF forests maintain unique assemblages with minimal overlap in community composition. Given ongoing anthropogenic pressures, particularly petroleum extraction, and those resulting from climate change, a greater understanding of the richness, diversity and community assemblages of Yasuní rainforest are needed to better conserve the fauna of this megadiverse area of Amazonia.

The impact of DNA extract homogenization and replication on marine sediment metabarcoding diversity and heterogeneity

AbstractMetabarcoding of environmental DNA (eDNA) is an attractive complement to morphological methods for surveys and routine monitoring of marine sediment benthic communities. However, metabarcoding and other genetic techniques are heavily affected by choices made during sampling, processing, and analysis. Here, we investigated the effect of different eDNA extraction protocols on observed alpha‐ and beta diversity of replicates from the same grab. Specifically, we compared (A) homogenization intensity during sediment DNA extraction, (B) extraction replicates vs larger sediment extraction volume, and (C) pre‐ and post‐PCR extract pooling. Using the 18S V1‐V2 region marker, we show that a Precellys homogenizer protocol during DNA extraction can significantly improve sediment metabarcoding results in terms of captured diversity and inter‐replicate homogeneity compared to vortexing only. This effect superseded that of increased sediment extract volume. Pre‐PCR pooling of DNA extraction replicates increased observed rarefied richness compared to data from single extracts only, but not to the extent of sample extract replicates amplified individually before pooling. We argue that this discrepancy was due to a reduction both in recovered sample diversity, but also the number of PCR artifacts and PCR drift. Our results demonstrate that extraction replicates of smaller sediment volumes, in combination with moderate Precellys homogenization and pre‐PCR pooling, are a cost‐effective way to increase the amount of organism diversity that is recovered from sediment eDNA metabarcoding samples.

Butterflies on the dry edge of the Atlantic Forest: water availability determines community structure at the Northern limit of Atlantic Forest

Abstract The composition of communities of fruit‐feeding butterflies in the Brazilian Atlantic forest changes in response to landscape fragmentation and can be used as an indicator of habitat quality. Landscape fragmentation, aridity, and early signs of global warming at the northernmost distribution of this biome may impose extra challenges for species persistence. We aim to clarify the drivers of fruit‐feeding butterflies' metacommunity structure in the northernmost portion of the Brazilian Atlantic Forest. We propose to disentangle consequences of habitat loss from fragmentation per se by using both habitat amount and patch scale metrics. We sampled fruit‐feeding butterflies in 15 forest fragments of up to ~30 ha during 1 year. We used fragment size, shape, distance to nearest perennial stream, Euclidean distance to nearest neighbour, forest habitat amount, proximity index, and the percentage of sugarcane within a buffer to elucidate patterns of species richness, abundance, and beta diversity. A configuration metric, stream distance, was the only variable predicting metacommunity total abundance and richness: fragments farther from water had fewer species and individuals. However, forest habitat amount and sugar cane were important to rarefied richness and species replacement between fragments. Our findings suggest that streams and associated riparian zones provide source populations for the butterfly metacommunities in this landscape, which fits the mass effect model. We also emphasise that small forest patches have high conservation value for persistence of butterfly populations, because each fragment preserves a substantial portion of the total species pool.

Mid-Late Pleistocene Neanderthal landscapes in southern Italy: Paleoecological contributions of the avian assemblage from Grotta del Cavallo, Apulia, southern Italy

We present a detailed paleoecologic analysis of avian assemblages from the Mousterian layers of the Middle Paleolithic Grotta del Cavallo site in southern Italy. Findings improve knowledge of the landscape that was exploited by Neanderthals. During the MIS 7, 6 and 3, the cave was surrounded by extensive grasslands and shrublands, locally interspersed by open woodland and rocky outcrops, whereas the coastal plain (currently underwater) hosted wetlands. Water bird taxa show an increase in population size during the cool-temperate climatic interval attributed to MIS 3, possibly linked to more humid conditions or a shorter distance between the wetland settings and the cave, compared to the previous glacial phase (MIS 6). In addition, coverage-based rarefied richness suggests higher avian diversity during MIS 3, which may reflect greater landscape heterogeneity due to the presence of wetland habitats. The tentative discovery of Branta leucopsis, together with several bird species currently found at higher altitudes, reinforces geochemically-derived palaeoclimate inferences of cooler than the present conditions. These assemblages also include the first fossil occurrence of Larus genei worldwide, the first Italian occurrence of Emberiza calandra, the oldest Italian occurrence of Podiceps nigricollis, and the occurrence of the rarely reported Sylvia cf. communis. Taphonomic analyses indicate that bone modifications are mainly due to physical syn- and post-depositional processes, and that the assemblage mainly accumulated through short-range physical transport and the feeding activities of nocturnal raptors.

Anthropogenic Disturbance Impacts Mycorrhizal Communities and Abiotic Soil Properties: Implications for an Endemic Forest Disease

In forest ecosystems, habitat fragmentation negatively impacts stand structure and biodiversity; the resulting fragmented patches of forest have distinct, disturbed edge habitats that experience different environmental conditions than the interiors of the fragments. In southwest Western Australia, there is a large-scale decline of the keystone tree species Corymbia calophylla following fragmentation and land use change. These changes have altered stand structure and increased their susceptibility to an endemic fungal pathogen, Quambalaria coyrecup, which causes chronic canker disease especially along disturbed forest habitats. However, the impacts of fragmentation on belowground processes in this system are not well-understood. We examined the effects of fragmentation on abiotic soil properties and ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungal communities, and whether these belowground changes were drivers of disease incidence. We collected soil from 17 sites across the distribution range of C. calophylla. Soils were collected across a gradient from disturbed, diseased areas to undisturbed, disease-free areas. We analysed soil nutrients and grew C. calophylla plants as a bioassay host. Plants were harvested and roots collected after 6 months of growth. DNA was extracted from the roots, amplified using fungal specific primers and sequenced using Illumina MiSeq. Concentrations of key soil nutrients such as nitrogen, phosphorus and potassium were much higher along the disturbed, diseased edges in comparison to undisturbed areas. Disturbance altered the community composition of ECM and AM fungi; however, only ECM fungal communities had lower rarefied richness and diversity along the disturbed, diseased areas compared to undisturbed areas. Accounting for effects of disturbance, ECM fungal diversity and leaf litter depth were highly correlated with increased disease incidence in C. calophylla. In the face of global change, increased virulence of an endemic pathogen has emerged in this Mediterranean-type forest.

Butterflies of fragmented wet grassland in Western European lowland forests: Effects of vegetation, connectivity and plot size

Habitat fragmentation, as a result of habitat loss and degradation, is widely considered to be a major threat to biodiversity. Our study focused on the distribution, diversity and abundance of butterflies on 22 isolated plots, mainly consisting of wet grassland. The plots were surrounded by deciduous mixed forests and located in an agglomeration area close to Lake Zurich, Switzerland. In addition to vegetation parameters, we assessed structural connectivity, adapted to least cost distances, using digital surface and terrain models. The resulting mixed-effects models revealed on plot level that (1) Molinia meadows had a significantly positive effect on rarefied Simpson butterfly diversity, (2) structural connectivity had a highly significant negative impact on rarefied Simpson butterfly diversity, whereas (3) plot size showed a significant positive impact, and (4) higher butterfly abundance was strongly related to blossom density. Across plot level, Molinia meadows had a higher rarefied butterfly species richness and rarefied Simpson butterfly diversity than any of the other habitat types evaluated. Among the endangered target species, the preferences of the Alcon Blue Phengaris alcon alcon were consistent with (1) to (3), while those of the Marsh Fritillary's E. aurinia aurinia were not. (2) is discussed with regards to the predominant influence of habitat type, vegetation and plot size, relativizing the effect of structural connectivity on butterfly communities in presumably resilient metapopulations. Ongoing targeted maintenance measures in the study area provide a promising basis for the sustainable conservation of local butterfly communities in isolated wet grassland plots.

Interactive persistent effects of past land‐cover and its trajectory on tropical freshwater biodiversity

Abstract Evidence indicating that ecological communities show delayed responses to environmental change has raised the need to better understand the effects of landscape history on biodiversity. We investigated how freshwater biodiversity is related to both recent and past land use change in tropical river catchments. More specifically, we analysed the relationship between biodiversity and change in forest cover that occurred across five decades, including landscape trajectories of forest gain and loss. The abundance of stream insects showed a more delayed response to landscape change than rarefied richness, whereas the Tsallis diversity index was not related to past forest cover. However, both alpha diversity and local abundance were related to mean forest cover across the five decades when conditioned by the trajectory of change. We found a negative relationship between the historical mean of forest cover and community descriptors in streams embedded in landscapes on a trajectory of forest loss, but a positive relationship in landscapes on a trajectory of forest gain. We provide the first evidence of delayed responses of tropical freshwater insect communities to landscape history and suggest that the magnitude of change in forest cover, mediated by its trajectory, is a major driver of delayed responses. We show that a trajectory of forest loss might result in both immediate loss of species and a set of species doomed for future extinction. Synthesis and applications. Delayed responses of multispecies communities to past landscape changes depend on their extent, frequency and intensity. Our findings indicate that, beyond the relative amount of forest cover within river catchments, the magnitude of change in forest cover mediated by its historical trajectory can be a major driver of delayed responses in stream communities. We suggest that, if biodiversity conservation is the main aim, stream restoration should be prioritized in catchments with higher forest cover, as even under a forest gain trajectory, stream communities continue responding to past landscape changes depending on how widespread and intensive changes were.

Management of remnant tallgrass prairie by grazing or fire: effects on plant communities and soil properties

AbstractTallgrass prairie is a disturbance‐dependent ecosystem that has suffered steep declines in the midwestern United States. The necessity of disturbance, typically fire or grazing, presents challenges to managers who must apply them on increasingly small and fragmented parcels. The goal of this study was to compare effects of management using cattle grazing or fire on vegetation and soil characteristics to aid managers in making decisions regarding the kind of disturbance to apply. We selected 73 sites, of which 27 were managed solely by cattle grazing and 46 solely by fire, for at least 11 yr leading up to the study. We stratified the sites by prairie type (dry, mesic, and wet) and sampled frequency of plant species on randomly placed transects, supplemented with botanist‐directed walks, and collected and composited five soil cores on a randomly selected transect within each prairie type at each site. We calculated rarefied richness and Shannon evenness from the transect data and mean coefficient of conservatism (CofC) from the total list of species. Soil samples were analyzed for texture, bulk density, total N and C, and potential net N nitrification and mineralization. A nonmetric multidimensional scaling analysis of the plant community data revealed differences in species associated with mesic and wet prairies, but no separation by management type. Similarly, none of the vegetation variables we calculated varied by management type, as determined by mixed‐effects models, but soil bulk density was 17.5% higher and total N was 22% higher on grazed sites than burned sites. Sites burned more recently had higher species richness and mean CofC, but fire was not associated with any soil variables. Sites grazed more recently had higher bulk density, total N and C, and faster N cycling rates. Overall, 28% of plant species were found exclusively in one management type or the other, but these species did not vary in mean CofC. We conclude that, at the levels of burning and grazing intensity we studied, both management approaches produce similar C storage and vegetation responses. To maintain maximum diversity across the landscape, however, both approaches are necessary.

Composition and Structure of Aquatic Macroinvertebrate Communities in Mining Areas Streams (Côte d’Ivoire, West Africa)

The existence of mining areas for decades could potentially affect aquatic environments and human health. This study allowed assessing the effects of mining activities on streams in three mining areas (Hiré, Lauzoua and Tortiya). Macroinvertebrates were collected on eight campaigns at eight stations using a hand-net, an Ekman grab and surber net. Environmental variables were recorded also. In this study the conductivity values were higher in the locality of Hiré. It was between 154.2 μS / cm (Tchindégri station) and 1753 μS / cm (Tributary Gbloh station). The highest temperature values were recorded in the stations of Tortiya locality (24 o C: Bou 2; 33.1 o C: Bou 1). A total of 184 taxa distributed among nine classes, 20 orders, 80 families and comprising 14 401 individuals were recorded. Insecta were the most diversified class in macroinvertebrate community (84% of taxa collected, eight orders and 59 families). Ecological indices (Shannon Weiner, rarefied richness, Pielou’s evenness) were significantly low at Lauzoua (N'Téko station) and Hiré (Tributary Gbloh station) (Mann- Whitney test, P &lt;0.05). Ecological indices showed no significant variation between the stations of the locality of Tortiya. The PCA had grouped the stations into four clusters. Conductivity, ammonium, phosphate, nitrites, and nitrates were significantly higher (Mann- Whitney test, P &lt; 0.05) in cluster I (Tributary Gbloh station) Compared to other clusters. Eight taxa (Limnius sp., Liberonautes chaperi, Gordius sp., Phyllogomphus sp., Orectogyrus sp., Bezzia sp., Adenophlebiodes, Parasedodes sp.) were specific to Tchindégri station (Hiré) and six taxa (Naucoris sp., Amphiops sp., Hydrobius sp., Pseudobagous longulus, Culicinae and Gomphus sp.) were associated to the Bou 1 and Bou 2 stations (Tortiya).

Effectiveness of protected areas for the conservation of aquatic invertebrates: a study-case in southern Brazil

Abstract: Aim This work aimed to analyze the effectiveness of protected areas (PA) as maintainers of the fauna of benthic macroinvertebrates and the use of these in the water management of these areas. We tested the hypothesis that in streams located within the PA there will be greater abundance and diversity of organisms. Methods We collected macroinvertebrates in streams located inside and outside two PA in Southern Brazil: (Fritz Plaumann State Park, Santa Catarina, Teixeira Soares Municipal Natural Park, Rio Grande do Sul). In each stream we measured physical and chemical variables of the water. Three sub-samples of macroinvertebrates were collected on stony substrate with a Surber sampler and calculated abundance of organisms, rarefied richness, Shannon diversity and Evenness. Results The streams located in the interior of the PA presented well oxygenated waters and slightly basic pH. The electrical conductivity was higher in the external sections than the UC. We observed that rarefied richness, Shannon diversity and equitability were higher in the streams located inside the PA. PerMANOVA indicates that the composition was different between streams sections (p = 0.03) and PA (p = 0.01). Conclusions The use of organisms as bioindicators showed a potential response to the environmental integrity of streams. Thus, these organisms have potential for use by PA managers for monitoring and decision making on the maintenance of protected areas.

Composition, Structure and Functional Feeding of Aquatic Entomofauna in Kodjobou&amp;#233; Lake: Water Quality Assessment

The composition, structure and Functional Feeding Groups (FFGs) of aquatic insects were investigated in Kodjoboue lake (South-East of Cote d’Ivoire) to assess water quality. Four sites (K1 - K4) were sampled during eight campaigns. At each site aquatic insects were collected using a kick-net (25 × 20 cm, 500 μm mesh size). Environmental variables were also recorded during this period. Water was collected from each sampling site for nutrient (phosphorus, nitrate) analysis in laboratory. A total of 68 aquatic insect taxa belonging to six orders and 32 families were recorded during the study. Site K4, subject to intense agricultural activity, had the lower diversity and least balanced stand with the lowest values of Shannon-Weaver index, Pielou’s Evenness index and rarefied richness. The functional approach revealed five major FFGs: predators, scrapers, shredders, gatherers-collectors and filter-collectors. Among the different functional feeding groups, the percentage of predators was higher than that of other groups at all the sites. The P/R report indicated that our four sites are characterized as heterotrophic with K1 as the least heterotrophic. Focused Principal Component Analysis (FPCA) showed that parameters of water, like pH, dissolved oxygen, nitrate were statistically correlated with species abundance. The diversity and Functional Feeding Groups metrics of aquatic insects used to describe the state of Kodjoboue lake reveal its disturbed state.

Nestedness of insect assemblages in agriculture-impacted Atlantic forest streams

Agricultural land use causes habitats fragmentation and riparian vegetation removal, driving variability in the composition of aquatic insect assemblage in streams. We explored the effect of agriculture on the beta diversity of insect assemblages of Ephemeroptera, Plecoptera and Trichoptera (EPT) in Atlantic forest streams. We measured water physical and chemical variables and quantified the land cover of 10 stream catchments to determine the environmental integrity of the streams. The percentage of vegetation range was ∼6% to ∼47%, and agricultural land use range was ∼24% to ∼88%. We collected a total of 2632 individuals distributed in 30 genera. Trichoptera was the most abundant order (57%), followed by Ephemeroptera (41%) and Plecoptera (2%). The abundance was influenced by the higher agriculture practices in the streams adjacent areas. On the other hand, the oxygenated waters and higher percentages of riparian vegetation influenced the EPT rarefied richness. The beta diversity of EPT assemblages was structured by nestedness due to the influence agricultural activities. The variation in the agricultural intensity that occurs in the streams generated more intense limnological variability, which caused the nestedness of EPT insects as well as the reduction of taxonomic richness. Thus, the streams with low environmental integrity had EPT assemblages nested in streams of high environmental integrity.