Forest fragmentation is a reality in several Brazilian regions due to high deforestation rates. Studies on these fragments are fundamental, as they enable monitoring and predicting the ...transformations of populations and isolated plant communities. This work aimed to evaluate the edge effect on the phytosociological and floristic structure of a Montane Seasonal Semi-deciduous Forest fragment in Vitória da Conquista, BA, Brazil. The methodology used is a hierarchical and divisive classification of species (TWINSPAN), which enables identifying groups of species which characterize each sample, but is rarely used in the literature in this context. The studied fragment is influenced by the edge effect, evidenced by the increase in the average height and diameter of individuals towards the fragment interior. The addition to a clear distinction between species compositions, being minimized 90 m away from the edge.
The earth is now subject to climate change and habitat deterioration on unprecedented scales. Monitoring climate change and habitat loss alone is insufficient if we are to understand the effects of ...these factors on complex biological communities. It is therefore important to identify bioindicator taxa that show measurable responses to climate change and habitat loss and that reflect wider-scale impacts on the biota of interest. We argue that bats have enormous potential as bioindicators: they show taxonomic stability, trends in their populations can be monitored, short- and long-term effects on populations can be measured and they are distributed widely around the globe. Because insectivorous bats occupy high trophic levels, they are sensitive to accumulations of pesticides and other toxins, and changes in their abundance may reflect changes in populations of arthropod prey species. Bats provide several ecosystem services, and hence reflect the status of the plant populations on which they feed and pollinate as well as the productivity of insect communities. Bat populations are affected by a wide range of stressors that affect many other taxa. In particular, changes in bat numbers or activity can be related to climate change (including extremes of drought, heat, cold and precipitation, cyclones and sea level rise), deterioration of water quality, agricultural intensification, loss and fragmentation of forests, fatalities at wind turbines, disease, pesticide use and overhunting. There is an urgent need to implement a global network for monitoring bat populations so their role as bioindicators can be used to its full potential.
Mangrove habitats support taxonomically diverse benthic communities, yet their effects on microphytobenthos remain understudied. This study investigated the benthic diatom community structure of 17 ...microtidal mangrove estuaries situated along the east coast of South Africa. High sediment organic content (≤ 18.1 %) and clay fraction (≤ 17.5 %) measured in the Avicennia marina and Rhizophora mucronata habitats favoured diverse communities (H′ > 3) and the presence of unique benthic diatom species such as Gyrosigma balticum. The habitat complexity and stabilisation provided by the mangrove forests served as microrefugia for colonisation of benthic diatoms. Taxa displayed a broad range of nutrient tolerance, with some nutrient tolerant species (e.g., Halamphora acutiuscula, Navicula clausii, Navicula gregaria, and Navicula radiosa) dominating the communities in the Mbashe and Mnyameni estuaries. The presence of these nutrient tolerant taxa in relatively pristine systems serves as an early warning for possible anthropogenic nutrient enrichment.
•Low-nutrient conditions supported a diverse benthic diatom community.•Benthic diatom diversity was higher (H′ >3) in the mangrove habitats.•The finer cohesive mangrove sediments favoured the proliferation of select taxa.•Lower diversity (H′ < 2) due to higher flow were unique to the control habitat.•Some nutrient tolerant taxa were recorded in select estuaries.
Aim: Integration of macroecology and palaeoecology is an important trend in understanding rapidly changing marine ecosystems. However, the spatial mismatch between these two data types has led to ...difficulties in interpretation, particularly for short-lived phytoplankton and their microfossils. Fronts are narrow transition zones between distinct water masses and play an essential role in partitioning phytoplankton assemblages in the ocean. Whether they also delimit microfossil assemblages deposited at the sea floor is unclear. We examined the correlation between quasi-stationary mesoscale fronts and the spatial distribution of microfossils (diatoms, dinoflagellates and silicoflagellates) in the Bohai, Yellow and East China Seas, to establish a causal link between microfossil assemblages and the factors controlling pelagic species assemblages on continental shelves. Location: China. Time period: 2003–2015. Major taxa studied: Phytoplankton. Methods: Front locations were determined using gradient analysis of monthly satellite sea surface temperature (SST) for 2003–2015. Microfossil assemblages were classified using two-way indicator species analysis of the relative abundance of 345 species collected from surface sediments at 126 sites. The relationships between frontal patterns and microfossil assemblages were evaluated by superimposing maps of front location, microfossil distribution and environmental features in the main water masses and by canonical correspondence analysis. Results: Ten major fronts and four primary microfossil assemblages were identified. Analyses of the spatial patterns of fronts, microfossil assemblages, SST, salinity and nutrients revealed that the fronts partitioned the microfossils into assemblage types corresponding to the physicochemical features of the water masses. Main conclusions: Microfossil species assemblages and their indicator species are separated by mesoscale fronts and are correlated with water properties. Producing base maps of microfossil assemblages in relationship to SST fronts enables examination of the importance of quasi-stationary mesoscale fronts in constructing microfossil patterns on continental shelves. The results displayed potential for the interpretation sediment core data and their integration with the macroecological context.
Protists include all eukaryotes except plants, fungi and animals. They are an essential, yet often forgotten, component of the soil microbiome. Method developments have now furthered our ...understanding of the real taxonomic and functional diversity of soil protists. They occupy key roles in microbial foodwebs as consumers of bacteria, fungi and other small eukaryotes. As parasites of plants, animals and even of larger protists, they regulate populations and shape communities. Pathogenic forms play a major role in public health issues as human parasites, or act as agricultural pests. Predatory soil protists release nutrients enhancing plant growth. Soil protists are of key importance for our understanding of eukaryotic evolution and microbial biogeography. Soil protists are also useful in applied research as bioindicators of soil quality, as models in ecotoxicology and as potential biofertilizers and biocontrol agents. In this review, we provide an overview of the enormous morphological, taxonomical and functional diversity of soil protists, and discuss current challenges and opportunities in soil protistology. Research in soil biology would clearly benefit from incorporating more protistology alongside the study of bacteria, fungi and animals.
The accumulation of potentially toxic elements (PTEs) in aquatic ecosystems has become a global concern, as PTEs may exert a wide range of toxicological impacts on aquatic organisms. Submerged plants ...and the microorganisms attached to their surfaces, however, have displayed great potential as a means of coping with such pollution. Therefore, it is crucial to understand the transport pathways of PTEs across sediment and organisms as well as their accumulation mechanisms in the presence of submerged plants and their biofilms. The majority of previous studies have demonstrated that submerged plants and their biofilms are indicators of PTE pollution in the aquatic environment, yet relatively little is known about PTE accumulation in epiphytic biofilms. In this review, we describe the transport pathways of PTEs in the aquatic environment in order to offer remarkable insights into bioaccumulation mechanisms in submerged plants and their biofilms. Based on the literature cited in this review, the roles of epiphytic biofilms in bioaccumulation and as an indicator of ecosystem health are discussed.
•PTEs transport through different media in aquatic environments.•Bioaccumulation mechanisms of PTEs were studied for submerged plants and biofilms.•Submerged plants and biofilms served as indicators of PTE pollution.•Potential bioaccumulating and bioindicating roles of epiphytic biofilm is addressed.
Mercury (Hg) occurs naturally in soil and can reach high concentrations in the environment due to anthropogenic activities; however, little is known about its impact on the soil microbiome. Here, we ...tested the impact of different concentrations of Hg on soil bacterial and fungal communities by carrying out microcosm experiments with seven different forest soils. The highest concentration of Hg (32 μg Hg g−1 dry soil) caused severe diversity loss and shifts in the bacterial and fungal community structures and composition. Bioavailable Hg was reduced in soils with the highest proportion of clay, but the impact of Hg on microbial community structures was still evident in these soils. Lower concentrations of Hg (≤3.2 μg Hg g−1 dry soil) had only a limited effect on the soil microbiome. Fungal communities were generally less affected than the bacterial communities. The bacterial Hg-detoxification capacity, as assessed by mercuric reductase gene abundance, was reduced in soils with the lowest amount bioavailable Hg. We found a wide range of Hg-responsive taxa in soils spiked with high amounts of Hg, although they were generally not specific to any soil type or taxonomic group. Overall, our data show that the impacts of Hg on the soil microbiome and its detoxification responses depend on soil characteristics.
•Mercury caused severe diversity loss and shifts in the soil microbiome.•Fungal communities were generally less affected than the bacterial ones.•A wide range of mercury-responsive taxa were found.•Mercuric reductase genes were enhanced in soils with high Hg.
Microplastics (MP; 1 μm to 1 mm) of various shapes and compositions are ingested by numerous marine animals. Recently, proposals have been made to adopt bivalve molluscs as bioindicators of MP ...pollution. To serve as indicators of MP pollution, however, the proposed organisms should ingest, without bias, the majority of plastic particles to which they are exposed. To test this premise, eastern oysters, Crassostrea virginica, and blue mussels, Mytilus edulis, were offered variously sized polystyrene microspheres (diameters 19–1000 μm) and nylon microfibers (lengths 75–1075 × diameter 30 μm), and the proportion of each rejected in pseudofeces and egested in feces was determined. For both species, the proportion of microspheres rejected increased from ca. 10–30% for the smallest spheres to 98% for the largest spheres. A higher proportion of the largest microsphere was rejected compared with the longest microfiber, but similar proportions of microfibers were ingested regardless of length. Differential egestion of MP also occurred. As a result of particle selection, the number and types of MP found in the bivalve gut will depend upon the physical characteristics of the particles. Thus, bivalves will be poor bioindicators of MP pollution in the environment, and it is advised that other marine species be explored.
A decade after environmental scientists integrated high‐throughput sequencing technologies in their toolbox, the genomics‐based monitoring of anthropogenic impacts on the biodiversity and functioning ...of ecosystems is yet to be implemented by regulatory frameworks. Despite the broadly acknowledged potential of environmental genomics to this end, technical limitations and conceptual issues still stand in the way of its broad application by end‐users. In addition, the multiplicity of potential implementation strategies may contribute to a perception that the routine application of this methodology is premature or “in development”, hence restraining regulators from binding these tools into legal frameworks. Here, we review recent implementations of environmental genomics‐based methods, applied to the biomonitoring of ecosystems. By taking a general overview, without narrowing our perspective to particular habitats or groups of organisms, this paper aims to compare, review and discuss the strengths and limitations of four general implementation strategies of environmental genomics for monitoring: (a) Taxonomy‐based analyses focused on identification of known bioindicators or described taxa; (b) De novo bioindicator analyses; (c) Structural community metrics including inferred ecological networks; and (d) Functional community metrics (metagenomics or metatranscriptomics). We emphasise the utility of the three latter strategies to integrate meiofauna and microorganisms that are not traditionally utilised in biomonitoring because of difficult taxonomic identification. Finally, we propose a roadmap for the implementation of environmental genomics into routine monitoring programmes that leverage recent analytical advancements, while pointing out current limitations and future research needs.
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