Elevated mercury exposure in bird communities inhabiting Artisanal and Small-Scale Gold Mining landscapes of the southeastern Peruvian Amazon.

Artisanal and Small-Scale Gold Mining (ASGM) represents a significant source of anthropogenic mercury emissions to the environment, with potentially severe implications for avian biodiversity. In the Madre de Dios department of the southern Peruvian Amazon, ASGM activities have created landscapes marred by deforestation and post-mining water bodies (mining ponds) with notable methylation potential. While data on Hg contamination in terrestrial wildlife remains limited, this study measures Hg exposure in several terrestrial bird species as bioindicators. Total Hg (THg) levels in feathers from birds near water bodies, including mining ponds associated with ASGM areas and oxbow lakes, were analyzed. Our results showed significantly higher Hg concentrations in birds from ASGM sites with mean ± SD of 3.14 ± 7.97 µg/g (range: 0.27 to 72.75 µg/g, n = 312) compared to control sites with a mean of 0.47 ± 0.42 µg/g (range: 0.04 to 1.89 µg/g, n = 52). Factors such as trophic guilds, ASGM presence, and water body area significantly influenced feather Hg concentrations. Notably, piscivorous birds exhibited the highest Hg concentration (31.03 ± 25.25 µg/g, n = 12) exceeding known concentrations that affect reproductive success, where one measurement of Chloroceryle americana (Green kingfisher; 72.7 µg/g) is among the highest ever reported in South America. This research quantifies Hg exposure in avian communities in Amazonian regions affected by ASGM, highlighting potential risks to regional bird populations.

Metabarcoding reveals that mixed forests mitigate negative effects of non-native trees on canopy arthropod diversity.

Averting climate change-induced forest diebacks increasingly relies on tree species planted outside of their natural range and on the addition of non-native tree species to mixed-species forests. However, the consequences of such changes for associated biodiversity remain poorly understood, especially for the forest canopy as a largely understudied forest stratum. Here, we used flight interception traps and a metabarcoding approach to study the taxonomic and functional (trophic guilds) composition and taxon richness of canopy arthropods. We sampled 15 monospecific and mixed stands of native European beech, native Norway spruce-planted outside its natural range-and non-native Douglas fir in northwest Germany. We found that the diversity of arthropods was lower in non-native Douglas fir compared with native beech stands. Taxon richness of herbivores was reduced by both conifer species. Other functional guilds, however, were not affected by stand type. Arthropod composition differed strongly between native broadleaved beech and monospecific coniferous (native spruce or non-native Douglas fir) stands, with less pronounced differences between the native and non-native conifers. Beech-conifer mixtures consistently hosted intermediate arthropod diversity and community composition compared with the respective monospecific stands. Moreover, arthropod diversity had a positive relationship with the number of canopy microhabitats. Our study shows that considering arthropod taxa of multiple functional groups reveals the multifaceted impact of non-native tree species on forest canopy arthropod communities. Contrasting with previous studies that primarily focused on the forest floor, we found that native beech hosts a rich diversity of arthropods, compared with lower diversity and distinct communities in economically attractive, and especially in non-native, conifers with few canopy microhabitats. Broadleaf-conifer mixtures did not perform better than native beech stands, but mitigated the negative effects of conifers, making such mixtures a compromise to foster both forest-associated diversity and economic yield.

Changes in Coleopteran assemblages over a successional chronosequence in a Mexican tropical dry forest.

Coleopterans are the most diverse animal group on Earth and constitute good indicators of environmental change. However, little information is available about Coleopteran communities' responses to disturbance and land-use change. Tropical dry forests have undergone especially extensive anthropogenic impacts in the past decades. This has led to mosaic landscapes consisting of areas of primary forest surrounded by pastures, agricultural fields and secondary forests, which negatively impacts many taxonomic groups. However, such impacts have not been assessed for most arthropod groups. In this work, we compared the abundance, richness and diversity of Coleopteran morphospecies in four different successional stages in a tropical dry forest in western Mexico, to answer the question: How do Coleopteran assemblages associate with vegetation change over the course of forest succession? In addition, we assessed the family composition and trophic guilds for the four successional stages. We found 971 Coleopterans belonging to 107 morphospecies distributed in 28 families. Coleopteran abundance and richness were greatest for pastures than for latter successional stages, and the most abundant family was Chrysomelidae, with 29% of the individuals. Herbivores were the most abundant guild, accounting for 57% of the individuals, followed by predators (22%) and saprophages (21%) beetles. Given the high diversity and richness found throughout the successional chronosequence of the studied tropical dry forest, in order to have the maximum number of species associated with tropical dry forests, large tracts of forest should be preserved so that successional dynamics are able to occur naturally.

Colonial waterbirds provide persistent subsidies to swamp forests along an estuarine island food chain.

Birds are excellent vectors of allochthonous matter and energy due to their high mobility, with more intense flow when waterbirds congregate in breeding colonies, feeding in surrounding aquatic and terrestrial areas, and promoting nutritional pulses to nutrient-poor environments. In southern Brazil, a swamp forest on an estuarine island is used by waterbirds for breeding, providing an opportunity to investigate the potential effects of transport of matter between nutrient-rich environments. Soil, plants, invertebrates, and blood from terrestrial birds were collected and stable isotopes compared to similar organisms in a control site without heronries. Values of δ15N and δ13C from waterbirds were higher in the colony in comparison to the control site (spatial effect). The enrichment of 15N and 13C provided during the active colony period persisted after the breeding period, especially for δ15N, which was higher in all compartments (temporal effect). Moreover, the enrichment of 15N occurred along the entire trophic chain (vertical effect) in the colony environment, including different guilds of invertebrates and land birds. The enrichment in 13C seems to lose strength and was mostly explained by factors such as trophic guild rather than site, especially in birds. Bayesian mixture models with terrestrial vs. estuarine endpoints demonstrated that all organisms from both colony and control environments had assimilated estuarine matter. Finally, detritivorous invertebrates showed greater assimilation when compared to other guilds. This study demonstrates that adjacent nutrient-rich environments, such as palustrine forests and estuaries, are nutritionally enriched in several dimensions from nearby autochthonous subsidies that are maintained throughout the year.

Evaluating total mercury and methylmercury biomagnification using stable isotopes of carbon and nitrogen in fish from the Madeira River basin, Brazilian Amazon.

The isotopic signatures of carbon in primary consumer fish species in the Madeira River basin (Western Amazon) follow a pattern, with basal species feeding mainly on C3 (e.g., vascular plants and phytoplankton). In this study with 196 specimens of 19 fish species and six trophic guilds, significant differences were found between the two main groups of primary consumers (herbivores and detritivores) in the Madeira River basin. The mercury and δ15N data indicated that the fish specimens collected in Puruzinho and Cuniã Lakes provided greater trophic magnification factors (TMFs) for this metal than those found in the corresponding rivers. In relation to total mercury (0.09-2.07 µg g-1) and methylmercury (0.05-1.91 µg g-1) concentrations, the piscivorous/carnivorous species exceeded the values recommended by the World Health Organization, with a [MeHg:THg] ratio of about 80%. Preventive and educational practices should be adopted to reduce the possible toxic effects of Hg in the riverside population, for whom fish constitutes the main protein source. Also, biomonitoring of the fish species in the Madeira River should be conducted on an ongoing basis to detect possible alterations in mercury concentrations.

Composition of terrestrial mammal assemblages and their habitat use in unflooded and flooded blackwater forests in the Central Amazon.

Several forest types compose the apparently homogenous forest landscape of the lowland Amazon. The seasonally flooded forests (igapós) of the narrow floodplains of the blackwater rivers of the Amazon basin support their community of animals; however, these animals are required to adapt to survive in this environment. Furthermore, several taxa are an important source of seasonal resources for the animals in the adjacent unflooded forest (terra firme). During the low-water phase, the igapó becomes available to terrestrial species that make use of terra firme and igapó forests. Nonetheless, these lateral movements of terrestrial mammals between hydrologically distinct forest types remain poorly understood. This study tested the hypothesis that the attributes of the assemblages (abundance, richness, evenness, and functional groups) of the terrestrial mammals in both these forest types of the Cuieiras River basin, which is located in the Central Amazon, are distinct and arise from the ecological heterogeneity induced by seasonal floods. After a sampling effort of 10,743 camera trap days over four campaigns, two for the terra firme (6,013 trap days) and two for the igapó forests (4,730 trap days), a total of 31 mammal species (five were considered eventual) were recorded in both forest types. The species richness was similar in the igapó and terra firme forests, and the species abundance and biomass were greater in the terra firme forest, which were probably due to its higher primary productivity; whereas the evenness was increased in the igapós when compared to the terra firme forest. Although both forest types shared 84% of the species, generally a marked difference was observed in the composition of the terrestrial mammal species. These differences were associated with abundances of some specific functional groups, i.e., frugivores/granivores. Within-group variation was explained by balanced variation in abundance and turnover, which the individuals of a given species at one site were substituted by an equivalent number of individuals of a different species at another site. However, the occupancy was similar between both forest types for some groups such as carnivores. These findings indicate that seasonal flooding is a relevant factor in structuring the composition of terrestrial mammal assemblages between terra firme and floodplain forests, even in nutrient-poor habitats such as igapós. The results also highlight the importance of maintaining the mosaic of natural habitats on the scale of the entire landscape, with major drainage basins representing management units that provide sufficiently large areas to support a range of ecological processes (e.g., nutrient transport, lateral movements and the persistence of apex predators).

Local Climate Conditions Shape the Seasonal Patterns of the Diptera Community in a Tropical Rainforest of the Americas.

Insect life cycles are short-term and therefore sensitive to immediate changes triggered by climate, vegetation structure, or land use management; hence, the insect populations shape the communities and functional relationships in tropical forests. In this study, we hypothesized that seasonal variations of the dipteran families respond in different ways to changes of weather conditions, thereby affecting their population dynamics. In a one-hectare plot, we surveyed the fly community inhabiting the understory of a Neotropical rainforest. Over a yearly cycle, we used three Malaise traps operated continuously for 365 days and recorded a total of 68,465 fly specimens belonging to 48 families of Diptera, 15 of which were most abundant, accounting for 99.2% of all sampled individuals. The results of the trapping frequency indices (TFIs) exhibited significant population fluctuations in 12 of the 15 most abundant families, which were particularly correlated with temperature or precipitation. Based on such variations, we identified four seasonal patterns as follows: (i) Spring-Autumn bimodal pattern (Cecidomyiidae, Sciaridae, Phoridae, Stratiomyidae); (ii) Spring pattern (Mycetophilidae, Dolichopodidae, Ceratopogonidae); (iii) Autumn pattern (Chironomidae, Psychodidae); (iv) Winter pattern (Empididae, Tipulidae, Ditomyiidae). From a functional perspective, we found the prevalence of families with saprophagous larvae, in addition to phytophagous, fungivores, and predacious. Our results suggest a key role played by the Diptera community on structuring the functional clusters, both in terms of taxonomic composition and on seasonal shifts of abundance, thus influencing the dynamic processes of nutrient cycling in the understory.

Multifunctionality of belowground food webs: resource, size and spatial energy channels.

The belowground compartment of terrestrial ecosystems drives nutrient cycling, the decomposition and stabilisation of organic matter, and supports aboveground life. Belowground consumers create complex food webs that regulate functioning, ensure stability and support biodiversity both below and above ground. However, existing soil food-web reconstructions do not match recently accumulated empirical evidence and there is no comprehensive reproducible approach that accounts for the complex resource, size and spatial structure of food webs in soil. Here I build on generic food-web organisation principles and use multifunctional classification of soil protists, invertebrates and vertebrates, to reconstruct a 'multichannel' food web across size classes of soil-associated consumers. I infer weighted trophic interactions among trophic guilds using feeding preferences and prey protection traits (evolutionarily inherited traits), size and spatial distributions (niche overlaps), and biomass-dependent feeding. I then use food-web reconstruction, together with assimilation efficiencies, to calculate energy fluxes assuming a steady-state energetic system. Based on energy fluxes, I propose a number of indicators, related to stability, biodiversity and multiple ecosystem-level functions such as herbivory, top-down control, translocation and transformation of organic matter. I illustrate this approach with an empirical example, comparing it with traditional resource-focused soil food-web reconstruction. The multichannel reconstruction can be used to assess 'trophic multifunctionality' (analogous to ecosystem multifunctionality), i.e. simultaneous support of multiple trophic functions by the food web, and compare it across communities and ecosystems spanning beyond the soil. With further empirical validation of the proposed functional indicators, this multichannel reconstruction approach could provide an effective tool for understanding animal diversity-ecosystem functioning relationships in soil. This tool hopefully will inspire more researchers to describe soil communities and belowground-aboveground interactions comprehensively. Such studies will provide informative indicators for including consumers as active agents in biogeochemical models, not only locally but also on regional and global scales.

Feeding habits and multifunctional classification of soil-associated consumers from protists to vertebrates.

Soil organisms drive major ecosystem functions by mineralising carbon and releasing nutrients during decomposition processes, which supports plant growth, aboveground biodiversity and, ultimately, human nutrition. Soil ecologists often operate with functional groups to infer the effects of individual taxa on ecosystem functions and services. Simultaneous assessment of the functional roles of multiple taxa is possible using food-web reconstructions, but our knowledge of the feeding habits of many taxa is insufficient and often based on limited evidence. Over the last two decades, molecular, biochemical and isotopic tools have improved our understanding of the feeding habits of various soil organisms, yet this knowledge is still to be synthesised into a common functional framework. Here, we provide a comprehensive review of the feeding habits of consumers in soil, including protists, micro-, meso- and macrofauna (invertebrates), and soil-associated vertebrates. We have integrated existing functional group classifications with findings gained with novel methods and compiled an overarching classification across taxa focusing on key universal traits such as food resource preferences, body masses, microhabitat specialisation, protection and hunting mechanisms. Our summary highlights various strands of evidence that many functional groups commonly used in soil ecology and food-web models are feeding on multiple types of food resources. In many cases, omnivory is observed down to the species level of taxonomic resolution, challenging realism of traditional soil food-web models based on distinct resource-based energy channels. Novel methods, such as stable isotope, fatty acid and DNA gut content analyses, have revealed previously hidden facets of trophic relationships of soil consumers, such as food assimilation, multichannel feeding across trophic levels, hidden trophic niche differentiation and the importance of alternative food/prey, as well as energy transfers across ecosystem compartments. Wider adoption of such tools and the development of open interoperable platforms that assemble morphological, ecological and trophic data as traits of soil taxa will enable the refinement and expansion of the multifunctional classification of consumers in soil. The compiled multifunctional classification of soil-associated consumers will serve as a reference for ecologists working with biodiversity changes and biodiversity-ecosystem functioning relationships, making soil food-web research more accessible and reproducible.

Potential use of distinct biomarkers (trace metals, micronuclei, and nuclear abnormalities) in a heterogeneous sample of birds in southern Brazil.

The analysis of metal concentrations in bird feathers and genotoxicity tests are tools used to evaluate anthropogenic impacts on ecosystems. We investigated the response of birds, used as bioindicators, to disturbances observed in three areas with distinctive environmental characteristics (natural, agricultural, and urban) in southern Brazil. For this purpose, we quantified metals (Mn, Cu, Cr, and Zn) in feathers and determined the number of micronuclei (MN) and other nuclear abnormalities (NA) in 108 birds from 25 species and 17 families captured in the study area. No significant differences was found in the metal concentrations and the number of MN and NA between the sampling areas. Zn and Cu concentrations were significantly higher in insectivorous than those in omnivorous birds. The Zn concentration was significantly different between some species, and the Cu concentration was significantly higher in juveniles than that in adults. The best generalized linear models showed that omnivorous birds had more MN and NA and that juveniles and birds with better body condition index had increased NA numbers. This study demonstrates that the analyzed variables contribute in different ways to the result of each biomarker, mainly due to particular ecological and physiological characteristics of each species. We conclude that wild birds have the potential to be used as environmental bioindicators in the study area, but future studies should focus on one or a few species whose ecological and physiological habits are well known.

Vertical stratification of arthropods in the dry ecosystems of Colombian Guyana: morphological patterns and their ecological implications / Estratificación vertical de artrópodos en ecosistemas secos de la Guayana colombiana: patrones morfológicos y sus implicaciones ecológicas

Abstract Introduction: Despite growing interest by the ecosystems derived from the Guyanese formations, the vertical structure of the communities and relationships of the biota with the climatic conditions in these ecosystems are unknown. Objective: Characterize the structure and vertical composition of the arthropod fauna associated with three of the most representative ecosystems of the Northern area of the serranía de La Lindosa in Colombia based on morphological and ecological parameters. Methods: The arthropod fauna was sampled, from the subsurface soil level to the shrub and tree stratum. The fauna was determined up to the level of family or supraspecific group and the values of Alfa and Beta diversity were determined. Body length measurements were made, and the coloration and trophic level of each group were determined. Results: The composition and diversity of the arthropod fauna was different in each ecosystem and vertical stratum and most of the groups in all the ecosystems studied present low abundances. Groups of phytophagous and predatory habits were frequent in all ecosystems and the highest biomass of arthropod fauna comes from groups of polyphagous habits, of medium size and great abundance. Light and dark colorations are the most frequent in landscape-scale. Conclusion: The ecosystems studied are characterized by the low values of diversity and replacement and the large number of non-shared groups that apparently respond to the microclimatic characteristics; however, there are some generalities on a landsc ape scale such as the greater richness and abundance of groups in the intermediate strata, the greater proportion of groups with phytophagous habits and medium body sizes, and the predominance of dark colorations in the lower strata.

Resumen Introducción: A pesar del interés que despiertan los ecosistemas derivados de las formaciones guyanesas, se desconoce la estructura vertical de las comunidades y las relaciones de la biota con las condiciones climáticas. Objetivo: Caracterizar la estructura y composición vertical de la artropofauna asociada a tres de los ecosistemas más representativos de la zona norte de la serranía de La Lindosa en Colombia, con base en parámetros morfológicos y ecológicos. Métodos: Se muestreó la artropofauna, desde el nivel del suelo subsuperficial hasta los estratos arbustivos y arbóreos, y se identificó hasta el nivel de familia o grupo supraespecífico. Se determinaron los valores de diversidad Alfa y Beta, se realizaron mediciones de la longitud corporal y se determinó la coloración y el nivel trófico de cada grupo. Resultados: La composición y diversidad de la artropofauna fue diferente en cada ecosistema y estrato vertical y la mayoría de los grupos de artrópodos en todos los ecosistemas estudiados presentan abundancias bajas. Los grupos de hábitos fitófagos y depredadores fueron frecuentes en todos los ecosistemas y la mayor biomasa de artropofauna proviene de grupos de hábitos polífagos, de tamaño medio y de gran abundancia. Las coloraciones claras y oscuras son las más frecuentes a escala de paisaje. Conclusión: Los ecosistemas estudiados se caracterizan por los bajos valores de diversidad y recambio y por la gran cantidad de grupos no compartidos que aparentemente responden a las características microclimáticas; sin embargo, existen algunas generalidades a escala de paisaje como la mayor riqueza y abundancia de grupos en los estratos intermedios, la mayor proporción de grupos de hábitos fitófagos y tallas corporales medianas y el predominio de coloraciones oscuras en los estratos inferiores.

Bat (Mammalia: Chiroptera) biodiversity in a subtropical inselberg ecosystem of Northeastern Argentina / Biodiversidad de murciélagos (Mammalia: Chiroptera) en un ecosistema inselberg subtropical del Noreste de Argentina

Abstract Introduction: Rocky outcrops influence both micro and macro habitat for plants and animals by increasing the availability and predictability of food, providing shelter, and unique microclimatic conditions. Objective: We describe the bat assemblage in three isolated rocky outcrops and their surrounding pediments, adding new data about trophic guilds and roosts. Methods: We surveyed the bat fauna of Paraje Tres Cerros, Corrientes Province, Argentina, exploring 13 sites during 26 field trips, using mist nets and search of roosts. We made an accumulation species curve and calculate inventory completeness. The similarity and composition of different habitats was compared by a Non-Metric Multidimensional Scaling (NMDS) and an ANOSIM test. Results: We reported 13 species, with a completeness inventory of the 80 % (Jacknife1), corresponding to the families Vespertilionidae, Molossidae and Phyllostomidae. The insectivorous bats were the best represented guild. We found nine types of roost for eight species in different sites. The analysis expressed low differences in the species composition between both types of habitats in the area. Conclusions: The rocky outcrops and their pediments are important ecosystems for the conservation and diversity of the bats in the region, since their assemblages are regionally unique.

Resumen Introducción: Los afloramientos rocosos influyen tanto en el micro como en el macro hábitat de plantas y animales al incrementar la disponibilidad de alimentos, proporcionar refugios y brindar condiciones microclimáticas únicas. Objetivo: Describir el ensamble de murciélagos en tres afloramientos rocosos aislados y sus pendientes circundantes, incorporando nuevos datos sobre gremios tróficos y refugios. Métodos: Muestreamos la fauna de murciélagos del Paraje Tres Cerros, provincia de Corrientes, Argentina, exploramos 13 sitios durante 26 viajes de campo, usando redes de niebla y búsqueda de refugios. Realizamos una curva de acumulación de especies y calculamos la completitud del inventario. La similitud y composición de diferentes hábitats se comparó mediante un escalado multidimensional no métrico (NMDS) y una prueba ANOSIM. Resultados: Reportamos 13 especies, con una completitud del 80 % del inventario (Jacknife1), correspondientes a las familias Vespertilionidae, Molossidae y Phyllostomidae. Los gremios mejor representados fueron los insectívoros. Encontramos nueve tipos de refugios para ocho especies en diferentes sitios. Los análisis expresaron bajas diferencias en la composición de especies entre ambos tipos de hábitats en el área. Conclusión: Los afloramientos rocosos y pendientes son ecosistemas importantes para la conservación y diversidad de los murciélagos en la región, ya que sus comunidades son regionalmente únicas.

Meta-analysis on the ecological impacts of widely spread non-indigenous species in the Baltic Sea.

The introduction of non-indigenous species (NIS) is a major driver for global change in species biogeography, often associated with significant consequences for recipient ecosystems and services they provide for humans. Despite mandated by several high-level international legislative instruments, comprehensive quantitative evaluation on ecosystem impacts of marine NIS is scarce and lack a robust and data-driven assessment framework. The current study is aiming at fulfilling this gap, through quantitative assessment on the effects of the widespread NIS of the Baltic Sea on multiple ecosystem features and components including direct food-web effects. The outcomes of this study allowed identifying the most impacting widespread NIS, together with defining the processes underlying the most significant changes and outlined major sources of uncertainty. Lack and/or bias in the availability of evidence of impacts was recorded for several (both recent and early) introductions. Realizing a sophisticated, data and information-hungry framework for the evaluation of ecosystem impacts of NIS is not pragmatic for management purposes in the foreseeable future. Instead, simple approaches, such as application of common statistical parameters like absolute effect size, are more likely to result in tangible outcomes. As bearing no unit, effect sizes can be later easily aggregated across taxa, affected ecosystem features or spatial scales. The proposed approach enables performing systematic comparisons on the severity of impacts of different NIS along different study disciplines and ecosystems.

Diversity Patterns of Tropical Epigeal Beetle Assemblages Associated with Monoculture and Polyculture Plantations with Big-Leaf Mahogany.

Although commercial forest plantations have experienced a major growth in the tropics over the past decades, little attention has been paid to their role in the conservation of epigeal arthropod communities. We studied diversity patterns of the epigeal beetle community in monoculture and polyculture forest plantations with big-leaf mahogany (Swietenia macrophylla). Likewise, we explored the existence of indicator species of each plantation type. Our findings highlight that each plantation type promotes multiple impacts on diversity patterns. We found that monocultures positively influenced overall beetle species richness and ecological diversity. When broken down by guild, both predator and decomposer species richness were similar between monoculture and polyculture, whereas for beetle diversity we found contrasting responses by guild: decomposer diversity was greater in monoculture whereas predator diversity was higher in polyculture. In addition, species composition differed between monoculture and polyculture, except for the predator guild. Species turnover was the main component explaining beta diversity patterns at all levels, indicating that each plantation type promotes biologically distinct epigeal assemblages. Few superabundant heliophile species dominated the beetle community structure; moreover, monocultures had a composition skewed towards heliophile species whereas polyculture favored umbrophile species. These patterns could be attributed to differences in habitat complexity between plot types, namely differences in tree cover. Additionally, indicator species only were identified in polycultures, reflecting their higher spatial complexity. Monoculture and polyculture plantations with big-leaf mahogany are complementary agroecosystems for preserving diverse epigeal beetle communities and should be considered valuable tools for conservation purposes in the tropics.

The invasive Asparagopsis taxiformis hosts a low diverse and less trophic structured molluscan assemblage compared with the native Ericaria brachycarpa.

Invasive seaweeds threaten biodiversity and socio-economics values of worldwide marine ecosystems. Understanding to what extent invasive seaweeds can modify local biodiversity is one of the main priorities in conservation ecology. We compared the molluscan assemblage of the invasive Asparagopsis taxiformis with that of the native Ericaria brachycarpa and explore if variation in the molluscan assemblage diversity was related to the substrate attributes (biomass, and thallus, canopy, and interstitial volumes) of the algae. Results showed that A. taxiformis harboured lower diversity and trophic structure of the molluscan assemblage compared to E. brachycarpa. Biomass was the variable that better explained the variation of abundance and number of species as well as the multivariate structure of the molluscan assemblage. Overall, our results suggest that a complete habitat shift from native to invasive species can potentially trigger bottom-up effects in rocky shores habitats, reducing the biodiversity and the services provided by the invaded habitat.

Bioaccumulation of 10 trace elements in juvenile fishes of the Lower Paraná River, Argentina: implications associated with essential fish growing habitat.

This study assessed the concentration, bioconcentration, and bioaccumulation of As, Cd, Co, Cr, Cu, Mg, Mn, Ni, Pb, and Zn in juvenile fishes (Acestrorynchus pantaneiro, Brycon orbygnianus, Cyphocharax voga, Megaleporinus obtusidens, Odontesthes bonariensis, Pimelodus maculatus, Prochilodus lineatus, Salminus brasiliensis, and Schizodon borelli) in the Lower Paraná River (Argentina), the most extensive floodplain from the Plata Basin. The floodplain is crucial for the reproduction and growth of various species such as P. lineatus, M. obtusidens, and S. brasiliensis, which complete their life cycle in this environment. In total, 90 individuals were sampled for nitrogen stable isotope, and trace element analysis in muscle tissue, water, and sediment was analyzed. The results show that all the studied species bioaccumulate Cr, Mg, Ni, and Zn. In particular, B. orbygnianus and P. maculatus presented the highest bioaccumulation factor for Cr. A biodilution of Co through the food chain was observed. No positive correlation was found between element concentration and trophic level, but we observed significant differences between trophic guilds (herbivorous, omnivorous, and carnivorous). Our findings suggest that feeding habits determine trace element concentrations. To establish differential behavior between different species within the aquatic web further studies are necessary, particularly in the floodplain of the Paraná, which is a crucial nursery area for most commercially important fishes from the Plata Basin. Graphical abstract.

Fish isotopic niches associated with environmental indicators and human disturbance along a disturbed large subtropical river in China.

Stable isotopes are increasingly used to detect and understand the impacts of environmental changes on riverine ecological properties. The δ13C and δ15N signatures of fish with different feeding habits were measured in a large subtropical river to evaluate how fish isotopic niches respond to environmental gradients and human disturbance. From basal resources to fish consumers, the high values of epilithic periphyton (biofilm) δ13C and suspended particulate organic matter δ15N concurrently determined the niche ranges and space (e.g., convex hull area) of fish communities. Along a longitudinal gradient (except in the industrial zone), the number of fish trophic guilds identified by Bayesian ellipses continuously increased; meanwhile, higher trophic diversity and less redundancy were observed near the lower reaches and estuary. Variance inflation factors were estimated to detect the multicollinearity of 40 environmental variables, 14 of which were selected as indicators. Relative importance (RI) analysis was used to evaluate the explanatory power of these indicators for the spatial variation in isotopic niche metrics; the results showed that riffle habitat area, water nitrate concentration, gravel-cobble substrate, and riparian buffer width were the 4 key environmental indicators (average RI > 12%) that determined the longitudinal pattern of fish isotopic niches. These findings suggested that community-level δ13C signatures are more responsive to changes in habitats (e.g., riffle) and substrates (e.g., gravel-cobble) supporting the productivity of autochthonous diatoms while δ15N signatures respond to water quality altered by nitrogen pollution from manure-fertilized farming and poultry livestock effluent. Furthermore, δ15N may be more robust and interpretable than δ13C as an isotopic indicator of ecosystem change in rivers exposed to multiple or complex anthropogenic stressors.

Birds of Parque Estadual Ilha do Cardoso: ecology, conservation and natural history / Aves do Parque Estadual Ilha do Cardos: ecologia, conservação e história natural

Abstract: The Parque Estadual Ilha do Cardoso (PEIC), located on extreme South of São Paulo's cost, in Brazil, holds an important Atlantic Forest remnant which still in a good state of conservation, but lack a deepen study about the avian community that habits the island. This study aimed to elaborate a census of avian species that occur in the park approaching richness, occurrence frequency, occurrence status and the structure of trophic guilds. A total of 25 field expedictions occurred between September 2015 and September 2017 during five days each, the field work included different ecosystems as mangrove, restinga, forest, sandbank, beach and marine. The census was made combine three different techniques used in ornithological studies: visual identification, auditory identification and catch by mist-nets (with five fixed sites in mangrove, restinga and forest). Were recorded 335 avian species, with 28 of them endemic from Brazil and 33 being threatened with extinction. Seventy-three species were recorded in all sampled months (FO 100%), while 46 were recorded in just one month (FO = 4%). About occurrence status, 55% of species are residents, 20% occasional visitors, 13% unusual residents, 6% migratory and 6% visitors. According the recorded species were recognized 25 trophic guilds based on food items, corporal size and strata that commonly forage, which of most representative in the community, the guild of "of insectivorous of medium-strata" (N = 55), "canopy omnivorous" (N = 33), "aquatic invertebrates consummers" and "piscivorous" (N = 31). Finally, with the current study, we aimed through a significative field effort bring a better knowledge about avifauna of PEIC, which could be a good base when is necessary take actions that aim to park management and the Conservation Unities around it.

Resumo: O Parque Estadual Ilha do Cardoso (PEIC), localizado no estremo sul do litoral paulista, reúne um importante remanescente de Floresta Atlântica em bom estado de conservação, carecendo, porém, de um estudo aprofundado sobre a comunidade de aves que habita a ilha. Diante disso, o presente estudo visou a elaborar um inventário das espécies de aves do parque abordando a riqueza, frequência de ocorrência, status de ocorrência e divisão das espécies em guildas. Foram realizadas entre setembro de 2015 e setembro de 2017, 25 expedições de campo com cinco dias de duração cada, incluindo os ecossistemas de manguezal, restinga, floresta, baixio, praia e marinho. O inventário foi realizado combinando três técnicas para estudos ornitológicos: identificação visual, identificação auditiva e captura com redes-de-neblina (cinco pontos fixos no manguezal, restinga e floresta). Foram registradas 335 espécies de aves, sendo 28 espécies consideradas endêmicas para o Brasil e 33 com algum grau de risco de extinção. Setenta e três espécies foram registradas em todos os meses amostrados (FO = 100%), enquanto que 46 apresentaram registros em apenas um mês (FO = 4%). No que se refere ao status de ocorrência, 55% das espécies são residentes, 20% visitantes ocasionais, 13% residentes incomuns, 6% migratórias e 6% visitantes. As espécies registradas permitiram o reconhecimento de 25 guildas com base nos itens alimentares, tamanho corporal e estrato em que comumente forrageiam, sendo as mais representativas na comunidade, as guildas de "Insetívoros de estrato médio" (N = 55), "Onívoros de copa" (N = 33), "Consumidores de Invertebrados Aquáticos" e "Piscívoros" (N = 31). Por fim, com o presente estudo, buscamos através de um significativo esforço em campo trazer um melhor conhecimento no que diz respeito a avifauna do PEIC, que pode vir a servir de base na hora de traçar ações visando ao manejo do parque bem como das unidades de conservação que se distribuem no seu entorno.

Contrasting Responses of Protistan Plant Parasites and Phagotrophs to Ecosystems, Land Management and Soil Properties.

Functional traits are increasingly used in ecology to link the structure of microbial communities to ecosystem processes. We investigated two important protistan lineages, Cercozoa and Endomyxa (Rhizaria) in soil using Illumina sequencing and analyzed their diversity and functional traits along with their responses to environmental factors in grassland and forest across Germany. From 600 soil samples, we obtained 2,101 Operational Taxonomic Units representing ∼18 million Illumina reads (region V4, 18S rRNA gene). All major taxonomic and functional groups were present, dominated by small bacterivorous flagellates (Glissomonadida). Endomyxan plant parasites were absent from forests. In grassland, Cercozoa and Endomyxa were promoted by more intensive land use management. Grassland and forest strikingly differed in community composition. Relative abundances of bacterivores and eukaryvores were inversely influenced by environmental factors. These patterns provide new insights into the functional organization of soil biota and indications for a more sustainable land-use management.

Plastic intake does not depend on fish eating habits: Identification of microplastics in the stomach contents of fish on an urban beach in Brazil.

This study aims to identify, classify, quantify the ingested microplastic by marine teleost fish, in order to analyze the relationship between microplastic and trophic guilds. Food items of 214 individuals of Opisthonema oglinum, Bagre marinus, Cathorops spixii, Sciades herzbergii, Chloroscombrus chrysurus, Conodon nobilis, Haemulopsis corvinaeformis were analyzed. The species were classified according to their trophic guilds (zoobenthivorous or opportunistic/omnivorous). All species ingested microplastic and contamination occurred independently of the trophic guild. Of the sampled fish, 55% were contaminated by microplastic. The most consumed categories were blue (28%) and transparent filaments (20%). Raman spectroscopy measurements detected that most sampled filament corresponds to blue synthetic fiber (polyester). This study can contribute by filling gaps in knowledge regarding sandy beach impacts, which are environments so highly threatened by human activities around the world and are neglected in terms of use and conservation plans.