Aquatic insects and their environmental predictors: a scientometric study focused on environmental monitoring in lotic environmental.

Since early studies about aquatic ecology, it has been found that changes in environmental conditions alter aquatic insect communities. Based on this, the combined study of environmental conditions and aquatic insect communities has become an important tool to monitor and manage freshwater systems. However, there is no consensus about which environmental predictors and facets of diversity are more useful for environmental monitoring. The objective of this work was to conduct a scientometric analysis to identify the main environmental predictors and biological groups used to monitor and manage lotic freshwater systems. We conducted a scientometric study on the Web of Science platform using the following words: stream, river, aquatic insect, Ephemeroptera, Plecoptera, Trichoptera, Odonata, Heteroptera, Chironomidae, bioindicator, environmental change, anthropic, and land use. Although most of the environmental predictors employed are local, intrinsic of freshwater systems using local environmental and associated landscape variables is a better strategy to predict aquatic insect communities. The facets of diversity most used are composition and richness of species and genera, which are not efficient at measuring the loss of ecosystem services and extinction of phylogenetic lineages. Although very important, these functional and phylogenetic facets are poorly explored for this purpose. Even though tropical regions are the most diverse globally and are experiencing major losses of native vegetation, these ecosystems are the least studied, a knowledge gap that needs addressing to better understand the effect of anthropogenic activities on the diversity of aquatic insects.

Amazonian Odonata Trait Bank.

Discussion regarding the gaps of knowledge on Odonata is common in the literature. Such gaps are even greater when dealing with basic biological data for biodiverse environments like the Amazon Rainforest. Therefore, studies that address, classify, and standardize functional traits allow the elaboration of a wide range of ecological and evolutionary hypotheses. Moreover, such endeavors aid conservation and management planning by providing a better understanding of which functional traits are filtered or favored under environmental changes. Here, our main goal was to produce a database with 68 functional traits of 218 Odonata species that occur in the Brazilian Amazon. We extracted data on behavior, habit/habitat (larvae and adults), thermoregulation, and geographic distribution from 419 literature sources classified into different research areas. Moreover, we measured 22 morphological traits of approximately 2500 adults and categorized species distributions based on approximately 40,000 geographic records for the Americas. As a result, we provided a functional matrix and identified different functional patterns for the Odonata suborders, as well as a strong relationship between the different trait categories. For this reason, we recommend the selection of key traits that represent a set of functional variables, reducing the sampling effort. In conclusion, we detect and discuss gaps in the literature and suggest research to be developed with the present Amazonian Odonata Trait Bank (AMO-TB).

Structuring of Dragonfly Communities (Insecta: Odonata) in Eastern Amazon: Effects of Environmental and Spatial Factors in Preserved and Altered Streams.

The evaluation of the effects of environmental factors on natural communities has been one of the principal approaches in ecology; although, over the past decade, increasing importance has been given to spatial factors. In this context, we evaluated the relative importance of environmental and spatial factors for the structuring of the local odonate communities in preserved and altered streams. Adult Odonata were sampled in 98 streams in eastern Amazonia, Brazil. The physical features of each stream were evaluated and spatial variables were generated. Only environmental factors accounted for the variation in the Odonata community. The same pattern was observed in the suborder Zygoptera. For Anisoptera, environmental factors alone affect the variation in the community, considering all the environments together, and the altered areas on their own. As the two Odonata suborders presented distinct responses to environmental factors, this partitioning may contribute to an improvement in the precision of studies in biomonitoring. We thus suggest that studies would have a greater explanatory potential if additional variables are included, related to biotic interactions (e.g., competition). This will require further investigation on a finer scale of environmental variation to determine how the Odonata fauna of Amazonian streams behaves under this analytical perspective.

The Response of Neotropical Dragonflies (Insecta: Odonata) to Local and Regional Abiotic Factors in Small Streams of the Amazon.

Since the relative role of local and regional abiotic factors on the Odonata diversity in rainforest streams is still poorly understood, we evaluated the effects of these factors on adult Odonata (Insecta) from preserved and altered streams in the Amazonian region. Adult Odonata were sampled in 98 streams in the Eastern Amazon, Pará, Brazil. Six variables were used to measure local environmental factors: habitat integrity index; mean canopy over the channel; and four physical and chemical descriptors of the water. To measure regional environmental factors, six variables were also used: altitude gradient, three bioclimatic variables and two percentage forest variables. In partial redundancy analysis, both abiotic factors (local and regional) were important to explain the variation in the Odonata community. The Odonata community can be influenced by regional and local factors. The relationship between Odonata and the local (e.g., integrity, canopy cover, and physical and chemical descriptors of the water) and regional (e.g., bioclimatic and forest cover variables) environmental variables recorded in this study has important implications for the use of these organisms to monitor small streams of the Eastern Amazon. The scale at which habitat is measured is an important issue in community structuring studies considering the rapid environmental changes. It is of great importance to consider the different scales in studies assessing community structure, once an adequate habitat must meet the ecological needs of all stages of the life of the Odonata.

Elements of metacommunity structure in Amazonian Zygoptera among streams under different spatial scales and environmental conditions.

An important aspect of conservation is to understand the founding elements and characteristics of metacommunities in natural environments, and the consequences of anthropogenic disturbance on these patterns. In natural Amazonian environments, the interfluves of the major rivers play an important role in the formation of areas of endemism through the historical isolation of species and the speciation process. We evaluated elements of metacommunity structure for Zygoptera (Insecta: Odonata) sampled in 93 Amazonian streams distributed in two distinct biogeographic regions (areas of endemism). Of sampled streams, 43 were considered to have experienced negligible anthropogenic impacts, and 50 were considered impacted by anthropogenic activities. Our hypothesis was that preserved ("negligible impact") streams would present a Clementsian pattern, forming clusters of distinct species, reflecting the biogeographic pattern of the two regions, and that anthropogenic streams would present random patterns of metacommunity, due to the loss of more sensitive species and dominance of more tolerant species, which have higher dispersal ability and environmental tolerance. In negligible impact streams, the Clementsian pattern reflected a strong biogeographic pattern, which we discuss considering the areas of endemism of Amazonian rivers. As for communities in human-impacted streams, a biotic homogenization was evident, in which rare species were suppressed and the most common species had become hyper-dominant. Understanding the mechanisms that trigger changes in metacommunities is an important issue for conservation, because they can help create mitigation measures for the impacts of anthropogenic activities on biological communities, and so should be expanded to studies using other taxonomic groups in both tropical and temperate systems, and, wherever possible, at multiple spatial scales.

Orchid bees (apddae: euglossini) in a forest frgment in the ecotone cerrado-ammazonian forest, Brazil / Abejas de orquídeas (Apidae: Euglossini) en un fragmento de bosque en el ecotono Cerrado-Selva Amazónica, Brasil

This paper presents information about the species richness and abundance of orchid bees in the transitional area between the Cerrado and the Amazon Forest in the Xingu river basin. The males were collected in a forest fragment in the municipality of Ribeirão Cascalheira, northeast Mato Grosso state, Brazil, between 1 and 5 November 2011. Benzyl benzoate, 1.8 cineole, eugenol and vanillin were used as baits, to attract the bees using insect nets and methyl salicylate was used only in the bottle traps. A total of 168 males belonged to four of five Euglossini genera distributed among 16 species were recorded. The greatest species richness was registered in the genus Euglossa, however Eulaema nigrita, was the most abundant Euglossine species in the community. The species richness varied between the edge and the first point within the fragment. The males were more active between 10:00 and 11:00 h, and the 1.8 cineole was the most attractive substance. The fragment studied contained representative species richness of orchid bees in a region of widespread environmental heterogeneity, which is still largely unknown as regards its pollinators and deserves attention for the compilation of new inventories.

En este trabajo se presenta información sobre la riqueza de especies y abundancia de Euglossini en la zona de transición entre el Cerrado y la selva amazónica, en la cuenca del río Xingu. Las muestras se recogieron en un fragmento de bosque en el municipio de Ribeirão Cascalheira, nordeste de Mato Grosso, Brasil, entre el 1 y 5 de noviembre de 2011. Las sustancias puras de benzoato de bencilo, 1,8 cineol, eugenol y la vainillina fueron utilizadas como cebos para atraer los machos usando red de insectos aunque el salicilato de metilo se utilizó en trampas pasivas. Un total de 168 machos pertenecientes a cuatro géneros fueron registrados, distribuidos en 16 especies. La mayor riqueza de especies se registró en el género Euglossa, aunque Eulaema nigrita fue la especie más abundante en la comunidad. La riqueza de especies varió entre el borde y el primer punto dentro del fragmento. Los machos de abejas de orquídeas eran más activos entre 10:00-11:00 h, y el 1,8 cineol fue la sustancia pura más atractiva. El fragmento estudiado contenía un alto grado de riqueza de especies de abejas de orquídeas en una región de heterogeneidad ambiental extensa, que sigue siendo en gran parte desconocido con relación a su fauna de insectos polinizadores y merece la atención para la elaboración de nuevos inventarios.

Composição e riqueza de Odonata (Insecta) em riachos com diferentes níveis de conservação em um ecótone Cerrado-Floresta Amazônica / Composition and richness of Odonata (Insecta) in streams with different levels of conservation in a Cerrado-Amazonian Forest ecotone

The removal or substitution of riparian vegetation causes disturbance in physical environment, seasonal water flow and water chemical quality. These modifications can cause decrease in species richness by local extinctions. The aim of this study was to examine the effect of disturbance in the physical environmental on the richness and species composition of Odonata adults in streams with different levels of conservation in the river Suiá-Missu basin, Mato Grosso, Brazil. Modifications in the aquatic systems affected the Odonata community, probably because their ecophysiological and behavioral requirements of adults and larvae. Anisoptera species, which require sunny environments because of their body size, had higher species richness in environments with low plant cover. On the other hand, Zygoptera species, which generally inhabit streams with dense vegetation, presented a decrease in richness in disturbed environments, as a result high sunlight radiation and/or variations in temperature. Hence, in both suborders, environmental perturbations do not need to be severe to change species composition, indicating that ecosystem services could be lost, even with only partial alterations in physical environment.

A retirada ou a substituição da vegetação ripária provoca uma alteração no ambiente físico, no fluxo sazonal e na qualidade química da água. Essas modificações podem causar a diminuição da riqueza pela extinção local de espécies. O objetivo deste trabalho foi avaliar o efeito do distúrbio da integridade ambiental sobre a riqueza e composição de espécies de Odonata adultos em córregos com diferentes níveis de conservação, na Bacia do Rio Suiá-Missu, Mato Grosso, Brasil. As modificações nos sistemas aquáticos afetaram a comunidade de Odonata, provavelmente devido às exigências ecofisiológicas e comportamentais relacionadas a adultos e larvas. Anisoptera, que necessitam de ambientes com maior incidência de sol devido ao tamanho do corpo, apresentaram maior riqueza de espécies em ambientes com menor cobertura vegetal. Por outro lado, os Zygoptera geralmente habitam riachos com cobertura vegetal mais densa, e por isso, apresentaram um decréscimo de sua riqueza em locais alterados, devido à maior entrada de luz e/ou variação do calor. Assim, para as duas subordens, as alterações ambientais não precisam ser severas para produzir modificações significativas na composição, indicando que os serviços ecossistêmicos poderiam ser perdidos, mesmo com alterações parciais do meio físico.