Papers by Francisco Valente Neto
We investigated (1) the variation of both species composition and species relative abundances of ... more We investigated (1) the variation of both species composition and species relative abundances of aquatic beetles associated with submerged woody debris in a transitional region between Cerrado (Brazilian savannah) and Atlantic Forest biomes; and (2) which assembling processes are more associated with the observed patterns, species sorting or mass effects. We hypothesized that the marked differences between Cerrado and Atlantic Forest streams regarding vegetation composition and structure would produce different environmental conditions for stream beetle faunas assembling. We used spatial explicit multivariate techniques to analyze whether metacom-munity patterns were more associated with environmental variables, indicating a major role of species sorting, or with spatial variables, indicating intense dispersal. We found distinct communities within each biome in terms of both changes in taxonomic composition and species relative abundance driven by environmental factors. Biome type, a regional scale variable, and variation in dissolved oxygen levels, a local scale variable, were the best explanatory variables of variation in metacommunity structure. We did not find any evidence of the influence of processes related to the spatial configuration of streams. Altogether our results pointed to species sorting structuring saproxylic beetles assemblages patterns.
Odonates are suggested as bioindicators of human impact. However, their complex life cycles add a... more Odonates are suggested as bioindicators of human impact. However, their complex life cycles add additional challenges in the practical use as bioindicators, because the level of taxonomic identification could be dependent on life-history stage and, during their ontogeny, dramatic changes occur in their niche (ontogenetic niche shifts). Considering that larvae and adults have different biological characteristics, which could interfere in their performance as bioindicators, we first sought to understand how similar or different environmental factors affect larval and adult life stages in the Odonata. Second, we assessed the level of congruence between (larvae and adult) and within (adult genera and species) life-history stages, considering the taxonomic and numerical resolution. We sampled larvae and adults in 44 streams distributed along a riverine network in southwest Brazil. Larvae samples constituted 20 sampling units of 1 m length each, using the kick sampling method; adults were collected for 1 h at each site with a hand net along a 100-m transect parallel to the stream/river banks. The influence of environmental factors on larvae and adult was assessed by redundancy analysis coupled with forward selection. The congruence level between response matrices was determined by Procrustes analysis. Our results revealed that a set of environmental variables explained a portion of larvae and adults distribution and some environmental factors affect both between (larvae and adults) and within (adult genera and species) life-history stages. Larvae and adult were about 54% congruent, regardless of taxonomic level of adults. Abundance of adult genera and species were 94% congruent, but numerical resolution (abundance vs. incidence) decreased the congruency by 10%. Environmental variables could influence larvae and adults individually or via carry-over effects, i.e., larval environmental conditions that could affect adult fitness components or vice versa. In addition, some odonate behaviors, such as female selection of more appropriate habitats for laying their eggs, could also help us to explain our results, because it could determine larvae distribution. In a biomonitoring perspective, considering the cost-benefit of taxonomic level and sampling of larvae and adults, our results suggest that abundance of adult genera could be used in biomonitoring programs since they capture, respectively, 94% and 54% of the information carried by adult species and larvae.
Reduced-impact logging (RIL) is an alternative land use because it reduces damage to forest cover... more Reduced-impact logging (RIL) is an alternative land use because it reduces damage to forest cover in comparison with clear-cut practices. However, management practices adopted in RIL can affect wood availability and, consequently, fauna associated with dead wood during part of their life cycle (saproxylic). In this study, we evaluated whether aquatic saproxylic macroinvertebrates are affected by reduced-impact logging in Central Amazonia. We selected six streams in areas under reduced-impacted logging and six in primary forest areas and collected submerged woody debris. We did not find any differences in water pH, conductivity, and wood availability between reduced-impacted forest and primary forest streams. We found 248 saproxylic aquatic macroinvertebrates belonging to 37 taxa. We found five wood specialist (Dryops, Lutrochus, Stenochironomus, Oukuriella, andEndotribelos) and 32 generalists, totalling 98 and 150 individuals, respectively. In general, our results show that reduced-impact logging does not affect richness, abundance, and composition of saproxylic
macroinvertebrates. The main explanation for this pattern is that management practices do not change important macroinvertebrate niche dimensions, including wood availability and the water’s chemical and physical variables. Thus, controlled logging, such as applied in the area of the Central Amazonian streams studied, opens a new prospect for insect conservation and commercial exploitation of wood, which is not possible when clear-cut practices are adopted.
http://link.springer.com/article/10.1007/s10452-015-9510-y
Riparian deforestation is one of th... more http://link.springer.com/article/10.1007/s10452-015-9510-y
Riparian deforestation is one of the main causes of change in freshwater ecosystems, resulting in the reduction of biological integrity and the loss of ecosystem functions. Our goal was to understand how a gradient of deforestation may affect abundance and richness of specialist and generalist macroinvertebrates associated with submerged woody debris in Neotropical streams. We conducted an observational study sampling mixed-species woody debris from 16 streams along a deforestation gradient. We also conducted an incubation study with known woody debris species (Cecropia pachystachya Trécul) in six streams. We collected 781 specimens and identified 50 taxa in the observational study, and we found 99 individuals belonging to 17 taxa in incubation study. Results from the two complementary studies indicate that the effect of riparian deforestation was more pronounced for wood specialists than generalists. Deforestation decreased the abundance and richness of wood specialists, and some taxa were locally extinct. The incubation study showed that sedimentation, which leads to the burying of woody debris, is an important process impeding macroinvertebrate colonization. Our study highlights the importance of woody debris as habitat for aquatic communities and as a structural component of streams, with important implications for conservation and biomonitoring. We suggest that wood specialists could be a potential group for use in biomonitoring programs aimed at assessing the impact of deforestation.
First record of larvae of Chironomidae (Insecta, Diptera) as prey of Temnocephala sp. (Platyhelmi... more First record of larvae of Chironomidae (Insecta, Diptera) as prey of Temnocephala sp. (Platyhelminthes, Temnocephalidae), an ectosymbiont on larvae of Corydalidae (Megaloptera). This study constitutes the first record of Temnocephala Blanchard, an ectosymbiont on Corydalidae, as a possible predator of chironomid larvae. Twenty-eight Corydalidae larvae (Corydalus and Protochauliodes) were examined under stereomicroscopic in search for Temnocephala and Chironomidae larvae, of which five megalopteran larvae had 24 Temnocephala sp. associated. Furthermore, eight of these Temnocephala worms had chironomid larvae in their gut contents, an interaction previously unknown. Gut content analyses revealed Corynoneura as the commonest chironomid, but larvae of Larsia, Rheotanytarsus and Tanytarsus were recorded as well. This study included Corydalus and Protochauliodes as hosts for Temnocephala, which might be important for this worm dispersion and population dynamics.
The family Elmidae Curtis, 1830 has cosmopolitan distribution and most species inhabit riffles on... more The family Elmidae Curtis, 1830 has cosmopolitan distribution and most species inhabit riffles on streams and rivers, hence the name "riffle beetle". In recent years, this family has been featured in papers addressing the assessment and environmental monitoring of water quality. In Brazil, studies on the family remain scarce and the present investigation is a pioneering study in the state of São Paulo. This study aims to propose a taxonomic key for the identification of larvae of Elmidae genera known to occur in the State, as well as to report new records and the distribution of these genera. The material analyzed was collected from various locations in each of 15 drainage basins from 2005 to 2010.
Information on the Elmidae that occur in a country is important for the advancement of ecological... more Information on the Elmidae that occur in a country is important for the advancement of ecological knowledge and the use of these organisms in biomonitoring programs. To date, there are checklists of elmids recorded in two regions of Brazilone for the Amazon region, listing 48 species in 14 genera, and another for the state of Rio de Janeiro, listing 13 species in 7 genera. Thus, there is no checklist of the Elmidae for Brazil as a whole, and only inconsistent estimates of the number of species present. Therefore, the aim of this paper is to present a checklist of the Elmidae recorded from Brazil. We based this checklist on literature produced between 1882 and 2011. A total of 148 species named plus 1 unnamed species of Elmidae are cited for Brazil, distributed in 24 genera. Moreover, we include taxonomic notes, such as changes in genus, and information about bibliography and distribution.
Uploads
Papers by Francisco Valente Neto
macroinvertebrates. The main explanation for this pattern is that management practices do not change important macroinvertebrate niche dimensions, including wood availability and the water’s chemical and physical variables. Thus, controlled logging, such as applied in the area of the Central Amazonian streams studied, opens a new prospect for insect conservation and commercial exploitation of wood, which is not possible when clear-cut practices are adopted.
Riparian deforestation is one of the main causes of change in freshwater ecosystems, resulting in the reduction of biological integrity and the loss of ecosystem functions. Our goal was to understand how a gradient of deforestation may affect abundance and richness of specialist and generalist macroinvertebrates associated with submerged woody debris in Neotropical streams. We conducted an observational study sampling mixed-species woody debris from 16 streams along a deforestation gradient. We also conducted an incubation study with known woody debris species (Cecropia pachystachya Trécul) in six streams. We collected 781 specimens and identified 50 taxa in the observational study, and we found 99 individuals belonging to 17 taxa in incubation study. Results from the two complementary studies indicate that the effect of riparian deforestation was more pronounced for wood specialists than generalists. Deforestation decreased the abundance and richness of wood specialists, and some taxa were locally extinct. The incubation study showed that sedimentation, which leads to the burying of woody debris, is an important process impeding macroinvertebrate colonization. Our study highlights the importance of woody debris as habitat for aquatic communities and as a structural component of streams, with important implications for conservation and biomonitoring. We suggest that wood specialists could be a potential group for use in biomonitoring programs aimed at assessing the impact of deforestation.
macroinvertebrates. The main explanation for this pattern is that management practices do not change important macroinvertebrate niche dimensions, including wood availability and the water’s chemical and physical variables. Thus, controlled logging, such as applied in the area of the Central Amazonian streams studied, opens a new prospect for insect conservation and commercial exploitation of wood, which is not possible when clear-cut practices are adopted.
Riparian deforestation is one of the main causes of change in freshwater ecosystems, resulting in the reduction of biological integrity and the loss of ecosystem functions. Our goal was to understand how a gradient of deforestation may affect abundance and richness of specialist and generalist macroinvertebrates associated with submerged woody debris in Neotropical streams. We conducted an observational study sampling mixed-species woody debris from 16 streams along a deforestation gradient. We also conducted an incubation study with known woody debris species (Cecropia pachystachya Trécul) in six streams. We collected 781 specimens and identified 50 taxa in the observational study, and we found 99 individuals belonging to 17 taxa in incubation study. Results from the two complementary studies indicate that the effect of riparian deforestation was more pronounced for wood specialists than generalists. Deforestation decreased the abundance and richness of wood specialists, and some taxa were locally extinct. The incubation study showed that sedimentation, which leads to the burying of woody debris, is an important process impeding macroinvertebrate colonization. Our study highlights the importance of woody debris as habitat for aquatic communities and as a structural component of streams, with important implications for conservation and biomonitoring. We suggest that wood specialists could be a potential group for use in biomonitoring programs aimed at assessing the impact of deforestation.