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opencc-zeroFeb 2022View details →

Parasitic trophic mode of plant host affects the extent of colonization, but does not induce systematic shifts in the composition of foliar endophytic assemblages in temperate meadow ecosystems

1. Foliar endophytic bacteria and fungi are increasingly being recognized as important drivers of plant host phenotype – affecting a wide range of eco-physiological processes. However, we are still lacking fundamental ecosystem-level knowledge about the structure, function, and inter-species interactions in endophytic assemblages associated with plant hosts sharing a common life strategy or ecological specialization. 2. In this study, we chose two groups of plants with contrasting physiology as model systems: parasites and their hosts. We assessed whether plant life history strategy, namely differences in nutrient acquisition and accumulation, plays a role in structuring above-ground microbiomes under field conditions. 3. We focused on the structure, colonization extent, and potential function of foliar endophytic bacteria and fungi in three root hemiparasitic species (Orobanchaceae), one stem holoparasite (Convolvulaceae), and their potential host plants co-occurring in species-rich temperate grassland ecosystems. For this purpose, we combined next generation amplicon sequencing with quantitative real-time PCR, chemical analyses of leaf tissue, and, in the case of bacteria, functional predictions using information deposited in available databases. 4. We found the foliar endophytic assemblages to be diverse, dominated by generalist taxa, but highly similar across all studied species. Despite of the highly contrasting leaf tissue chemistry in the parasitic and non-parasitic plant species, the parasitic trophic mode did not induce systematic shifts in the diversity, composition, or predicted biogeochemical function of the endophytic microbiomes under field conditions. However, compared to their potential hosts, leaves of both hemiparasitic and holoparasitic species harbored significantly lower fungal counts, estimated as ß-actin gene copies ng DNA-1, which suggests that parasitic plants may possess mechanisms to regulate the extent of colonization by endophytic fungi.

opencc-zeroJul 2022View details →

Fish assemblage composition of the four basins of Wannan Mountains, China

Extensive distribution of widespread species and the loss of native species driven by anthropogenic disturbances modify community similarity, resulting in a decrease or increase in community distinctiveness. Data from four basins in the Wannan Mountains, China, were used to evaluate the effects of low-head dams on patterns of fish faunal homogenization and differentiation based on abundance data. We aimed to examine the spatial changes in taxonomic and functional similarities of fish assemblages driven by low-head dams and whether the changes in the similarity of fish assemblages differed between taxonomic and functional components. We found that low-head dams significantly decreased the mean taxonomic similarity but increased the mean functional similarity of fish assemblages in impoundments using abundance-based approaches, suggesting that taxonomic differentiation accompanied functional homogenization in stream fish assemblages. These results show the importance of population abundance in structuring fish faunal homogenization and differentiation at small scales, especially when the major differences among assemblages are in species abundance ranks rather than species identities. Additionally, we also found only a weak positive correlation between changes in mean taxonomic and functional similarities, and partial pairs exhibited considerable variation in patterns of fish faunal homogenization and differentiation for taxonomic and functional components. In conclusion, this study highlighted that the observed taxonomic differentiation of current fish assemblages (short-term phenomenon) is probably an early warning sign of further homogenization in regions where native species are completely predominated, and that changes in taxonomic similarity cannot be used to predict changes in functional similarity. Keywords: Low-head dam, Stream fish, Biotic homogenization and differentiation, Taxonomic and functional diversities

opencc-zeroJun 2024View details →

Shifts in the composition and distribution of Pacific Arctic larval fish assemblages in response to rapid ecosystem change

The Pacific Arctic marine ecosystem has undergone rapid changes in recent years due to ocean warming, sea ice loss, and increased northward transport of Pacific‐origin waters into the Arctic. These climate‐mediated changes have been linked to range shifts of juvenile and adult subarctic (boreal) and Arctic fish populations, though it is unclear whether distributional changes are also occurring during the early life stages. We analyzed larval fish abundance and distribution data sampled in late summer from 2010 to 2019 in two interconnected Pacific Arctic ecosystems: the northern Bering Sea and Chukchi Sea, to determine whether recent warming and loss of sea ice have restricted habitat for Arctic species and altered larval fish assemblage composition from Arctic‐ to boreal‐associated taxa. Multivariate analyses revealed the presence of three distinct multi‐species assemblages across all years: (1) a boreal assemblage dominated by yellowfin sole (Limanda aspera), capelin (Mallotus catervarius), and walleye pollock (Gadus chalcogrammus); (2) an Arctic assemblage composed of Arctic cod (Boreogadus saida) and other common Arctic species; and (3) a mixed assemblage composed of the dominant species from the other two assemblages. We found that the wind‐ and current‐driven northward advection of warmer, subarctic waters and the unprecedented low‐ice conditions observed in the northern Bering and Chukchi seas beginning in 2017 and persisting into 2018 and 2019 have precipitated community‐wide shifts, with the boreal larval fish assemblage expanding northward and offshore and the Arctic assemblage retreating poleward. We conclude that Arctic warming is most significantly driving changes in abundance at the leading and trailing edges of the Chukchi Sea larval fish community as boreal species increase in abundance and Arctic species decline. Our analyses document how quickly larval fish assemblages respond to environmental change and reveal that the impacts of Arctic borealization on fish community composition spans multiple life stages over large spatial scales.

opencc-by-4.0Feb 2010View details →

Fig. 1 in Patterns in fish species composition and assemblage structure in the upper Salado River lakes, Pampa Plain, Argentina

Fig. 1. Schematic diagram of the study area in the upper Salado River, Pampa Plain, Argentina.

opencc-by-4.0Dec 2020View details →

FIGURE 4 in The effects of lithification on fossil assemblage biodiversity and composition: An experimental test

FIGURE 4. Rank abundance plots for the Bermont (A) and Fort Thompson (B) samples.

opencc-zeroJun 2021View details →

Source pool diversity and proximity shape the compositional uniqueness of insular mammal assemblages worldwide

Islands have been the test bed of several theories in community ecology, biogeography, and evolutionary biology. Progress within these disciplines has given a more comprehensive and mechanistic understanding of the processes governing variation in species richness among islands. However, it remains unclear whether these same processes also explain variation in species and phylogenetic composition among islands. Integrating theory from ecology and biogeography, we infer the roles of dispersal, selection, and stochasticity on the composition of insular assemblages within archipelagos. We further assess the influence of source pool diversity and connectivity on the compositional uniqueness of insular assemblages. Island systems worldwide. We compiled data on species composition of non-volant mammals on ∼200 islands in nine archipelagos distributed worldwide from the literature. We used variation partitioning to quantify the relative influence of the environment (selection) and geographic distance (dispersal) relative to a null model (stochasticity, randomness) on taxonomic and phylogenetic compositional turnover within archipelagos. We then used a linear mixed model to gain further insight into the underlying mechanisms shaping variation in assemblage composition among islands at a global scale. Specifically, we assessed the influence of source pool diversity, isolation from the source pool, and island characteristics on compositional uniqueness. Our results suggest that within-archipelago variation in the composition of insular mammal assemblages is associated with stochastic or unmeasured processes rather than abiotic selection or dispersal limitation. The diversity and proximity of the source pool, as well as some island characteristics, explained variation in phylogenetic, but not taxonomic, compositional uniqueness globally. Within archipelagos, the largely unexplained variation in compositional turnover points to the overwhelming influence of extinction mediated by ecological drift or other stochastic processes, which obscures or overrides the signature of selection and/or dispersal. Globally, isolated islands associated with highly diverse source pools exhibit high phylogenetic uniqueness whereas well-connected islands associated with small source pools show the opposite trend. Phylogenetically unique assemblages also tend to occur on islands with a small elevational span and low annual temperature variation. Taken together, our results suggest that source pool diversity, along with the potential for colonization from those pools, plays an important role in shaping the composition of insular mammal assemblages worldwide.

Fig. 20 in Taxonomic Composition And Systematics Of Late Cretaceous Lizard Assemblages From Ukhaa Tolgod And Adjacent Localities, Mongolian Gobi Desert

Fig. 20. Pyramicephalosaurus cherminicus: A, IGM 3/131, incomplete right maxilla with

Fig. 17 in Taxonomic Composition And Systematics Of Late Cretaceous Lizard Assemblages From Ukhaa Tolgod And Adjacent Localities, Mongolian Gobi Desert

Fig. 17. Gobinatus arenosus: A–D, IGM 3/126, incomplete skull with mandibles from Khulsan,

Fig. 9 in Taxonomic Composition And Systematics Of Late Cretaceous Lizard Assemblages From Ukhaa Tolgod And Adjacent Localities, Mongolian Gobi Desert

Fig. 9. Mimeosaurus crassus: A–C, IGM 3/

Fig. 34 in Taxonomic Composition And Systematics Of Late Cretaceous Lizard Assemblages From Ukhaa Tolgod And Adjacent Localities, Mongolian Gobi Desert

Fig. 34. Anguimorpha, Varanoidea, Aiolosaurus oriens, new genus and species: A–C, IGM 3/171,

Fig. 1 in Taxonomic Composition And Systematics Of Late Cretaceous Lizard Assemblages From Ukhaa Tolgod And Adjacent Localities, Mongolian Gobi Desert

Fig. 1. Map of Mongolian Gobi Desert showing major fossil localities.

opencc-by-4.0Jul 2023View details →

Volatile traps as a new supplementary method of light trap for assessing diversity and composition of Macroheterocera assemblages - RAW Data

Volatile traps as a new supplementary method of light trap for assessing diversity and composition of Macroheterocera assemblages - RAW Data