Similarity In Species Composition Research Articles

Long-term directional changes in urban bird communities of Mar del Plata City, Argentina

Urban environments have been characterized by their temporal stability of resources, which could promote stability in bird composition. Several studies have found that bird communities in urban environments persist over the years, showing a similar species composition in the short term. However, studies analyzing continuous changes in urban communities over the long term are scarce. This study aimed to analyze the stability or directional changes (instability) in bird communities along an urban gradient. Bird counts were conducted in urban, suburban, and periurban areas over 8-10 years in 2002-2019. Changes in species composition were analyzed over periods ranging from one year to the next, to changes from one year to the seventeenth. Urban bird communities were more similar between years than suburban and periurban communities. Compositional changes were greater as time lags increased, indicating directional compositional shifts. The magnitude of these changes was similar across the urban gradient. The Chimango Caracara (Milvago chimango), the Picazuro Pigeon (Patagioenas picazuro), the Rufous Hornero (Furnarius rufus), and the Red-bellied Thrush (Turdus rufiventris) significantly increased their abundances during the period, while the House Sparrow (Passer domesticus) significantly decreased its abundance. Regional changes in species abundance, urban vegetation succession, and biotic interactions could explain the changes in bird communities.

Effects of developmental stages, sex difference, and diet types of the host marmalade hoverfly (Episyrphus balteatus) on symbiotic bacteria.

Symbiotic bacteria play key roles in a variety of important life processes of insects such as development, reproduction and environmental adaptation, and the elucidation of symbiont population structure and dynamics is crucial for revealing the underlying regulatory mechanisms. The marmalade hoverfly (Episyrphus balteatus) is not only a remarkable aphid predator, but also a worldwide pollinator second to honeybees. However, its symbiont composition and dynamics remain unclear. Herein, we investigate the symbiotic bacterial dynamics in marmalade hoverfly throughout whole life cycle, across two sexes, and in its prey Megoura crassicauda by 16S rRNA sequencing. In general, the dominant phyla were Proteobacteria and Firmicutes, and the dominant genera were Serratia and Wolbachia. Serratia mainly existed in the larval stage of hoverfly with the highest relative abundance of 86.24% in the 1st instar larvae. Wolbachia was found in adults and eggs with the highest relative abundance of 62.80% in eggs. Significant difference in species diversity was observed between the adults feeding on pollen and larvae feeding on M. crassicauda, in which the dominant symbiotic bacteria were Asaia and Serratia, respectively. However, between two sexes, the symbionts exhibited high similarity in species composition. In addition, our results suggested that E. balteatus obtainded Serratia mainly through horizontal transmission by feeding on prey aphids, whereas it acquired Wolbachia mainly through intergeneration vertical transmission. Taken together, our study revealed the effects of development stages, diet types and genders of E. balteatus on symbionts, and explored transmission modes of dominant bacteria Serratia and Wolbachia. Our findings lay a foundation for further studying the roles of symbiotic bacteria in E. balteatus life cycle, which will benefit for revealing the co-adaptation mechanisms of insects and symbiotic bacteria.

Spatiotemporal Dynamics of Plankton Communities in the Chongqing Section of the National Nature Reserve for Rare and Endemic Fishes in the Upper Yangtze River

In order to understand the community structure of plankton and environmental factors in the Chongqing section of the National Nature Reserve for Rare and Endemic Fishes (referred to as the “Reserve”) along the upper Yangtze River, this study investigated phytoplankton and zooplankton in the water body from 2021 to 2022. The results revealed a diverse phytoplankton community with 243 species from 105 genera and 8 phyla, dominated by Bacillariophyta and Chlorophyta. Phytoplankton showed average densities of 1.7 × 106 cells/L and biomass of 2.6221 mg/L, following a seasonal pattern of summer > spring > winter. Zooplankton analysis identified 141 species from 77 genera and 4 phyla, with rotifers most abundant, followed by protozoa. Zooplankton displayed average densities of 0.17 × 104 ind./L and biomass of 0.3226 mg/L, also following a seasonal pattern of summer > spring > winter. Total phosphorus (TP) emerged as the primary environmental factor influencing plankton community structure, positively correlating with phytoplankton density and zooplankton biomass. Plankton biodiversity indices classified water quality in the Chongqing section of the “Reserve” as oligo-/mesotrophic. Overall, plankton diversity in this section is notably rich, with similar species composition between mainstems and tributaries but seasonal variations in community structure. While mainstem water quality generally meets standards, some tributaries exhibit varying degrees of pollution, underscoring the need for improved ecological management and protection measures. This is crucial for maintaining the sustainability of the ecosystem.

Clustering and unconstrained ordination with Dirichlet process mixture models

Abstract Assessment of similarity in species composition or abundance across sampled locations is a common goal in multi‐species monitoring programs. Existing ordination techniques provide a framework for clustering sample locations based on species composition by projecting high‐dimensional community data into a low‐dimensional, latent ecological gradient representing species composition. However, these techniques require specification of the number of distinct ecological communities present in the latent space, which can be difficult to determine in advance. We develop an ordination model capable of simultaneous clustering and ordination that allows for estimation of the number of clusters present in the latent ecological gradient. This model draws latent coordinates for each sample location from a Dirichlet process mixture model, affording researchers with probabilistic statements about the number of clusters present in the latent ecological gradient. The model is compared to existing methods for simultaneous clustering and ordination via simulation and applied to two empirical datasets; JAGS code to fit the proposed model is provided in an appendix. The first dataset concerns presence‐absence records of fish in the Doubs river in eastern France and the second dataset describes presence‐absence records of plant species in Craters of the Moon National Monument and Preserve (CRMO) in Idaho, USA. Results from both analyses align with existing ecological gradients at each location. Development of the Dirichlet process ordination model provides wildlife managers with data‐driven inferences about the number of distinct communities present across monitored locations, allowing for more cost‐effective monitoring and reliable decision‐making for conservation management.

Changes in vegetation composition and structure following landslide-induced disturbance in the Himalaya

The Himalaya cover 12% of India’s landmass and are prone to approximately one-seventh of global rainfall-triggered landslides. Still, very few studies have examined the after-effects of landslides on native vegetation structure and composition. This study aims to fulfil this gap by analysing the vegetation structure and composition of 10 landslide-impacted sites in Uttarakhand Himalaya along an elevational gradient between 1400-3500 m. The investigations revealed that physiognomically, the younger landslide-disturbed sites were dominated by herbaceous taxa while shrubs and trees dominated the older landslide-disturbed sites. Shannon-Wiener diversity values were highest at the old-low disturbed site compared to recent and young disturbed sites. Sorensen similarity index values indicated that the older landslide sites had the highest similarity in species composition of disturbed and undisturbed sites. The younger and recently disturbed landslide sites were highly dissimilar in species composition and structure as compared to the adjacent undisturbed sites. Notably, both the landslide-disturbed and undisturbed sites had a high percentage of native species (90-95%). The fundamental understanding developed from this study can have potential applications in evolving management practices for ecological restoration of the degraded ecosystems in the Himalaya and other mountain ecosystems around the world.

Comparison of the coexistence pattern of mangrove macrobenthos between natural and artificial reforestation.

The abandoned pond-to-mangrove restoration project provides greater advantages than tidal flats afforestation in restoring mangrove ecosystem services and will be the primary method for mangrove restoration in the future. The existing methods for abandoned pond-to-mangrove restoration include artificial restoration through 'dike-breaking, filling with imported soil and tree planting' and natural restoration through 'dike-breaking and natural succession'. However, little is known about which restoration strategy (natural or artificial restoration) provides more benefits to the biodiversity of mangrove macrobethos. Given a prevailing view suggested that artificial restoration should be the preferred approach for accelerating recovery of biodiversity and vegetation structure in tropical regions, we hypothesised higher macrobenthic biodiversity and more complex community structure in artificial restoration than in natural restoration. To test this hypothesis, macrobenthic biodiversity and ecological processes were monitored in a typical abandoned pond-to-mangrove area of Dongzhaigang Bay, China, where artificial and natural restoration methods were used concurrently. Differences in macrobenthic biodiversity, community structure and ecological processes were compared using diversity indices, complex network analysis and null models. Similar species composition and ecological niche overlap and width among macrobenthos were observed at artificial and natural restoration sites. The biotic heterogeneity and interaction among macrobenthos were higher at the natural restoration sites than at the artificial restoration sites. Macrobenthos community assembly at natural and artificial restoration sites was both determined by deterministic processes, with environmental filtering dominating, which explained 52% and 54% of the variations in macrobenthic community structures respectively. Although our findings did not validate the research hypothesis, higher biotic heterogeneity and species interaction among macrobenthos could support natural restoration as the primary method for abandoned pond-to-mangrove projects, because it is a nature-based solution for mangrove restoration.

Through the green mosaic: Different tropical vegetation types have complementary effects on parasitoid diversity and biological control in organic agroecosystems

Land use change threaten global biodiversity, impacting ecosystem services, especially in diverse tropical regions. Yet, biodiversity conservation does not guarantee ecosystem services provision, given species' variable responses to local and landscape factors. Here, we evaluate how the landscape and local resources affect parasitoid diversity and aphid biological control in a tropical organic crop. Locally, we compared parasitoid communities within the crops and on adjacent non-crop plant strips and evaluated the effect of flower resource abundance on parasitoid diversity. At the landscape scale, we analyzed the effect of natural areas and their specific vegetational types on parasitoid diversity and the scale of these effects. Finally, we evaluated the relationship between biodiversity and biological control. Non-crop plant strips had higher parasitoid species richness and abundance than the crops, but similar species composition. Flower resource abundance in the non-crop strips negatively affected parasitoid richness. Natural areas in the landscape benefited parasitoid richness at a close range (0.42 km) and reduced parasitoid abundance at a wider scale (1.75 km). Forests and savannas increased parasitoid richness and reduced abundance, while grasslands drive parasitoid abundance and may disrupt species richness. Savannah areas, where trees and grasses coexist boosted the positive effects of forests on species richness and of grasslands on abundance. Parasitoid species richness benefited biological control exclusively in communities with intermediate and high number of parasitoid species. Our findings show that natural vegetation types with different wood densities have complementary effects in parasitoid diversity in tropical agroecosystems and represent a useful baseline for development of management and zoning plans.

Medium and large-sized mammals in human-dominated landscape of the former Dhidhessa wildlife sanctuary, Western Ethiopia

Abstract Assessment of medium- and large-sized mammals’ species diversity, abundance, distribution, and habitat association is necessary to promote their conservation measures. The study was conducted in the former Dhidhessa wildlife sanctuary (FDWS), to assess the medium- and large-sized mammals’ composition, distribution, and diversity. Transect lines were used to collect the data. A total of 1,146 ± 91 individuals belonging to 25 species, seven orders, and 14 families were recorded. Among these, 607 ± 186.5 (52.97%) were recorded during the wet season, whereas 539 ± 144.5 (47.03%) during the dry season. The order Carnivora was the most diverse one, followed by Artiodactyla and Primates, respectively, while Rodentia, Hyracoidea, Tubulidentata, and Lagomorpha were the least diverse orders. Olive baboon (Papio anubis) was the most abundant species (19.2%), followed by Hippopotamus (Hippopotamus amphibious) (17.63%) and Vervet monkey (Chlorocebus aethiops) (13.18%). Species diversity was higher in the savanna-wooded than in the riverine forest during both the wet (H’ = 2.72, Fisher’s alpha = 6.33) and dry (H’= 2.79, Fisher’s alpha = 6.26) seasons. Species evenness was higher in the savanna-wooded habitat than in the riverine forest habitat during both the wet (J’ = 0.87 and J’ = 0.77, respectively) and dry (J’ = 0.9 and J’ = 0.80, respectively) seasons. The highest similarity in species composition was between the wet and dry seasons in the riverine forest habitat (SI = 85.58%). The lowest similarity was recorded between the dry and wet seasons of the riverine forest and the wet season of the savanna wooded habitat (SI = 45.46% and SI = 46.49%, respectively). The study suggests that mammals are at risk of anthropogenic factors in the area. So, an urgent conservation measure that involves the participation of the local community has paramount significance for the sustainable conservation of mammals in the former Dhidhessa wildlife sanctuary.

Transport and preservation of calcareous and organic-walled dinoflagellate cysts off Cape Blanc (NW africa) in relation to nepheloid layers

Our understanding of dinoflagellates' present-day and past ecology is limited due to the scarcity of data on the transport of dinoflagellate cysts in oceanic environments. Previous studies have shown that lateral transport affects the source-to-sink trajectory of cysts in the very productive region off Cape Blanc (NW Africa). Unsolved questions remain, such as: how far these cysts can be advected, whether the cyst sources vary over time and whether lateral transport is a permanent feature or restricted to individual events. To fill these gaps and assess the role of nepheloid layers on the lateral transport and preservation of dinoflagellate cysts, new data on dinoflagellate cyst distributions in the water column and sediments along a land-sea transect were obtained.Samples were collected in November 2018 along a shelf break-offshore transect during intense upwelling, notably, within and between the nepheloid layers. The composition and abundance of cysts with organic walls in the water column and surface sediments were studied. Moreover, the distribution of calcareous cysts was also analysed in the water samples, using non-destructive acid-free preparation methods. The records were dominated by empty cysts, but no clear indications that these originated from local resuspension of older sediments were observed. Clustering, principal component analysis and redundant discriminant analysis were used to compare cyst assemblages in the water column and surface sediments, and environmental conditions in the upper water column. The strong similarity in species composition of water samples collected in the active upwelling region to those collected from the more onshore parts of the Benthic Nepheloid Layer (BNL), upper Intermediate Nepheloid Layer (INL) (∼1000 m depth) and lower INL (∼2200 m depth) indicated that lateral transport of cysts within these NLs occurred until about ∼110 km from the shelf break. Cyst assemblages from above and below these NLs showed significantly different taxa composition reinforcing the role of NLs in the lateral advection of cysts. In the more offshore stations, vertically similar cyst assemblages were observed in the same station, independent of the sample depth, within or between the NLs, which supported that at these stations vertical transport was the dominant process influencing cyst assemblages. Consequently, the cyst signal in sediments off Cape Blanc may be affected both by horizontal transport of allochthonous cysts and vertical deposition of locally-produced cysts, particularly in the more offshore stations (>2000 m depth). Despite lateral transport and possible species-specific preservation effects, horizontal distributions of most cyst taxa in the water column and the surface sediments could be explained to a great extent by the main environmental gradients in the upper water column. This agrees with observations made in other regions, and reinforces that dinoflagellate cysts as good proxies to reconstruct past environmental conditions in offshore environments. New data on dinoflagellate cyst distribution, transport and accumulation patterns in deep environments off Cape Blanc may be useful for interpreting past environmental signals in the region. This is particularly relevant regarding calcareous cysts, as information on their distribution and ecology is very scarce. The present work contributes to a better understanding of the dispersal patterns of dinoflagellate cysts in the deep ocean, highlighting the significant role played by nepheloid layers in this process and thus on the dinoflagellate cyst signature in deep-sea sediments.

Temporal changes in species richness, composition and diversity of the forest stands over 36-year period, Western Himalaya, India

This study investigates the temporal changes in species richness, composition, and diversity in forest stands spanning a 36-year period in the Western Himalaya. Four forest stands (subtropical Sal-forest, subtropical Chir-pine forest, temperate Banj-oak forest, and temperate Mixed-oak Forest) studied in 1980–1981 were resurveyed using similar methods. Over the past 36 years, 19 new species have been recorded in the four stands; eight species planted and eleven species naturally introduced. Dominant species continue to dominate in the forest stands. However, their contribution to the total tree density has decreased over the year. Species diversity, richness, and evenness increased in all forests except the Sal stand. Three species were newly introduced in the Sal stand, seven in the Chir-pine stand, eight in the Banj-oak stand, and seven in the Mixed-oak stand. The highest similarity in species composition was observed in the Sal stand (59 %), followed by the mixed-oak stand (57 %), Chir-pine stand (50 %), and Banj-oak stand (47 %). The results indicate an increase in tree density across all sites, with the Mixed-oak forest exhibiting the highest increase in tree density due to least biotic pressure. The findings of this study, based on two-time composition datasets, provide valuable insights into forest dynamics, supporting biodiversity conservation and management planning.

Abandonment or biomass production? Phytodiversity responses to land-use changes of semi-natural grasslands in northern Europe

European semi-natural grasslands are hotspots for biodiversity and important for the provisioning of multiple ecosystem services, but their extent has declined considerably during the past century. Increasing demands for agricultural and forest biomass risk causing further loss of grasslands, raising concern about a goal conflict between climate mitigation and biodiversity conservation. This study focused on the loss of semi-natural grasslands in a mixed farm-forest landscape in southern Sweden by comparing plant diversity in grasslands with continuous grazing regimes to recently abandoned grasslands, improved grasslands (sown leys), and afforested grasslands. Compared to actively grazed grasslands, grasslands where grazing had been abandoned showed a lower plant species richness and fewer plant species of conservation concern, but similar species composition. In contrast, both improved and afforested grasslands showed >50 % lower species richness than abandoned and grazed grasslands, with profoundly different species composition. The dissimilarity in plant diversity between sites was primarily driven by the replacement of species (turnover), and trait-based analyses indicated that environmental filtering of light, management, and nutrient requirements of plants shaped the community differences. Furthermore, an increased cover of semi-natural grassland around the sites positively related to plant species richness and diversity, while an increased cropland coverage around the sites showed a negative relationship. Our results emphasize the importance of integrated land-use strategies that prioritize biodiversity conservation in mixed farm-forest landscapes, such as restoration of semi-natural grasslands and strategic planning of biomass production to avoid serious biodiversity losses.

Vertical distribution patterns of macrofauna in the sediments of the Arctic cross-shelf trough and adjacent shelf - Similarities and differences from lower latitudes

Vertical distribution of macrobenthos in sediments remains poorly studied; data from higher latitudes are especially scarce. At the same time, it is believed to contain important information about communities that should not be neglected. Hence, our main objectives are to study the peculiarities of macrobenthos vertical patterns in the Arctic and to find out features specific to this region. For this, 24 stations were sampled in 2019 aboard the R/V “Akademik Tryoshnikov” while drifting in the North Barents Sea and along a transect south-west of the Franz Joseph Land. Sediments were obtained using a box corer; afterwards, subsamples were taken by a tube corer and cut into vertical sub-cores. Three to four strata (depending on biotope) characterized by similar species composition and abundance were distinguished. No direct relation between the increase in species richness and the complication of vertical structure was found. Avoiding competition through dwelling in different layers at one station was observed in some groups of closely related species. Factors playing important roles in determining infaunal properties depended on the layer. The thin upper layer played a more important role in terms of species number and abundance as compared to lower latitudes. However, the most abundant and widespread polychaete species Spiochaetopterus typicus penetrated down to 30 cm. It formed vertical distribution patterns in deeper sediment layers at most stations, including facilitating penetration into deep layers for other species. The exception was stations dominated by large maldanid polychaetes. Such a vertical pattern, with a particularly large share of species richness and abundance concentrated in the several upper cm combined with the very deep penetration of a few species, is likely typical of the Eurasian Arctic shelf.

Structure and Carbon Capture of a Temperate Mixed Forest across Altitudinal Gradients in Northern Mexico

Maximizing the ability of forests to capture carbon (C) from the atmosphere is critical to mitigate global warming. This is a daunting task as the warming climate is adversely affecting forests with increasing forest fires, pests, and a shift to tree species that can tolerate the newer climate conditions. A large (about 1 million hectares) mixed pine–oak forest in Chihuahua, Mexico, was characterized via 151 plots to determine its floristic diversity and biomass with respect to species, age (tree diameter), and at four altitudinal gradients equally distributed between 1850 and 2850 masl. Higher richness and diversity were found at the altitudinal gradient of 2101–2350 m with 36 species and a Shannon’s index (H’) of 2.95, and the lowest at 2601–2850 m with 17 species and H’ of 2.37. The Sorensen Index showed a high similarity in species composition, with the highest values (71% to 79%) obtained for the 2351–2600 gradient. C storage of the mixed forest increased with altitude from 7.85 Mg C ha−1 in the 1850–2100 m gradient to 14.82 Mg C ha−1 in the 2601–2850 m gradient. C storage in oak decreased with altitude while C storage of pine increased. Viable strategies to maximize C storage under changing climate conditions are discussed, including social safeguards and sale of carbon credits.

Current Status and Resources of Alhagi pseudalhagi (Fabaceae) in the Atyrau Region, Western Kazakhstan

Alhagi pseudalhagi, which grows in the arid zone of the Atyrau region, and an assessment of the current state of its raw material reserves were studied. Botanical characteristics, ontogenetic spectra, morphological indicators, productivity, areas of thickets, and reserves of raw materials of above-ground organs were assessed. The structural parameters of these populations in the Zhangyr and Coneu Rivers valleys, in the vicinity of Imankara Mountain, and on the Taisoigan sands were studied. It was established that the species composition of the populations includes 63 species from 54 genera and 30 families. The most common species include 49 species, which, according to their occurrence in populations of A. pseudalhagi, are distributed in the following classes: 17 species—class II (0–20%); 7 species—class III (41–60%); and 2 species—classes IV (61–80%) and V (81–100%). The maximum similarity in species composition was noted between populations in the Zhangyr and Coneu Rivers valleys. The highest morphometric indicators were observed among the population of the Coneu river valley, and the lowest are located on the Taisoigan sands. Analysis of the age spectra made it possible to determine that the populations in the Zhangyr and Coneu River valleys are characterized as young and those in the area of Imankara Mountain and on the Taisoigan sands as stable and middle-aged.

Effects of land use and climate on the diversity and population structure in natural stands of Detarium microcarpum Guill. & Perr. (Fabaceae) in Burkina Faso (West Africa)

Detarium microcarpum Guill. & Perr. is a multipurpose species, providing many ecosystem services. However, in its geographical range, its multiple uses represent a major challenge to the sustainable management and conservation of its resources. This study aimed to determine the effect of climatic zones, land uses, and their interaction on the natural stands of D. microcarpum. Inventories were conducted in 165 plots in two climatic zones and land use types in Burkina Faso. Hill diversity indices were used to determine the effects of climatic zones, land uses, and their interaction on D. microcarpum stand diversity. Generalized linear models were used to assess the effect of the abiotic and biotic factors on the species' structural parameters. Land uses and climatic zones significantly affected D. microcarpum stand diversity and structure. The lowest stand diversity was recorded in the unprotected areas. The similarity in woody species composition between land uses and climatic zones was low, indicating high beta diversity. The generalized linear model showed that rainfall, temperature, habitat heterospecific density, and habitat-specific richness significantly influenced the structural parameters of the D. microcarpum population. The diameter classes’ distribution revealed unstable populations for the adult stratum, independent of climatic zones and land use types, except for the protected area in the Sudanian zone. The height class distribution of the juvenile stratum highlighted the instability regeneration of D. microcarpum populations. This study highlighted the instability of D. microcarpum populations and the specific effects of biotic and abiotic variables on the species' structural parameters. Thus, the findings suggest urgent conservation measures to ensure sustainable utilisation and management of the species.

Latitudinal variation in seagrass communities with special emphasis on post-tsunami status in the Andaman and Nicobar archipelago, India.

We studied spatial variation in seagrass communities in the Andaman and Nicobar archipelago (ANI), India using latitude as a surrogate variable. We classified the ANI into five latitudinally distinct island groups: North & Middle Andaman, Ritchie's archipelago, South Andaman, Little Andaman, and the Nicobar archipelago. We evaluated the Importance Value Index (IVI) for species to determine the ecologically dominant seagrasses within each Island group. Later, we related our findings to investigate the three decadal pre- and post-tsunami status of seagrass habitats in the ANI which were severely impacted by the Indian Ocean tsunami of 2004. Six of the 11 observed species, such as Halophila ovalis, Halophila beccarii, Halophila minor, Halodule pinifolia, Thalassia hemprichii, and Cymodocea rotundata, dominated the seagrass population among all island groups. Seagrass composition significantly varied across the five investigated latitudinal gradients. Seagrass communities in 'Ritchie's Archipelago and Nicobar' and 'South Andaman and Little Andaman' revealed the highest and lowest variation. Further, Ritchie's Archipelago and Nicobar had the highest species richness (n = 10), followed by North & Middle Andaman (n = 8), and the lowest in South and Little Andaman (n = 6). Despite similar species richness and composition, Nicobar contributed to the highest seagrass coverage compared to the lowest recorded in the Ritchie's Archipelago. Our observations on the re-colonization of disturbed areas by early successional and historical species suggest recovery of the seagrass population in the ANI post-disturbance. Lastly, co-variates associated with latitude as a surrogate warrant further investigation.

Legume (Fabaceae) and seed beetle (Coleoptera, Chrysomelidae, Bruchinae) species of Europe: distribution and host specialization

The paper investigates the distributions of legumes (Fabaceae) and their associated seed beetle species (Bruchinae) across vegetation zones and regions of Europe and evaluates the host range and specialization of seed beetles. 1584 legume species/subspecies/varieties were included in the study and ca. 16% of these serve as known hosts by the 175 seed beetle species found in Europe. Both plant and seed beetle species richness increased from the Boreal to Mediterranean zones/regions. 717 legume species occurred only in single zones/regions and only 4.7% of these (34 species) were hosts for 38 bruchine species specific to a zone/region. Europe has 664 native legume species and 381 of these are Eu-endemics. There were 52 alien legume species found. Similarities in plant species composition by the Sørensen index were pronounced between the Central-European and the Mediterranean, between the Transcaucasian and Mediterranean, and between the Colchis-Caucasian and the Pontic-Caspian areas. The most species-rich genus is Astragalus L. with 334 species and 16 subspecies. Of the two major pre-dispersal seed predator genera, Bruchidius Schilsky species are sensu lato oligophagous, using a wide range of leguminous tribes as hosts, but restricted to few host species within a tribe. In contrast, members of the Bruchus L. genus are sensu stricto oligophagous species and, despite being constrained to the Fabeae tribe, most of them feed on several Lathyrus L. and Vicia L. species. The ways annual and perennial life cycles as well as chemical constituents of legumes might affect the colonization success of the seed beetles are discussed.

Endophytic Fungal Diversity of Mangrove Ferns Acrostichum speciosum and A. aureum in China.

Microbial communities are an important component of mangrove ecosystems. In order to reveal the diversity of endophytic fungi in the mangrove ferns Acrostichum speciosum and A. aureum in China, the internal transcribed spacer (ITS) regions of endophytic fungi in four plant tissues (leaves, petioles, roots, and rhizomes) from three locations (Zhanjiang, Haikou, and Wenchang) were sequenced. The richness, species composition, and community similarity were analyzed. The main results are as follows: the dominant fungi in A. speciosum and A. aureum belonged to the phyla Ascomycota and Basidiomycota, accounting for more than 75% of the total identified fungi; in terms of species composition at the operational taxonomic unit (OTU) level, the endophytic fungi in A. aureum were more diverse than those in A. speciosum, and the endophytic fungi in rhizomes were more diverse than in other tissues. In Zhanjiang, both A. speciosum and A. aureum showed the richest diversity of endophytic fungi, both at the OTU classification level and in terms of species composition. Conversely, the richness of endophytic fungi in the samples of A. speciosum from Wenchang and Haikou is extremely low. The regional differences in dominant fungi increase with the degrading of taxonomic levels, and there were also significant differences in the number of unique fungi among different origins, with Zhanjiang samples having a larger number of unique fungi than the other locations. There were significant differences in the dominant fungi among different tissues, with Xylariales being the dominant fungi in rhizomes of A. speciosum and Hypocreales being the dominant fungi in the petioles, roots, and rhizomes of A. aureum. Overall, the community similarity of endophytic fungi among locations is moderately dissimilar (26-50%), while the similarity between tissues is moderately similar (51-75%). The low diversity of endophytic fungi could be one of the main reasons for the endangerment of A. speciosum. The protection of the diversity of endophytic fungi in the underground parts of A. speciosum is essential for the conservation of this critically endangered mangrove fern.

Effect of fast heating rate and alkaline catalyst on composition and characteristic of volatile products during catalytic upgrading of oil sand bitumen

The study was devoted to exploring the fundamental study on the upgrading of Buton oil sand bitumen (OSB) via fast alkaline catalytic pyrolysis based on the fluid pyrolysis technology. The effect of fast heating rate on the composition and molecular distribution of volatile products from the high-temperature fast pyrolysis of OSB was investigated by Py-GC/TOF-MS that could simulate the fast heating rate of industrial fluid pyrolysis process. The results showed that the volatile products of OSB under heating rates ranging from 10 to 1000 °C/s had the similar species composition. It was found that there were the highest relative content of low-carbon alkenes (C2-C4) and light aromatics (C6-C8) in volatile products under the 1000 °C/s, indicating that the fast heating rate favored the production of light alkenes and aromatics. Subsequently, a laboratory-scale fluidized bed apparatus was employed to further gain insight into fast alkaline catalytic pyrolysis behaviors of OSB. The investigation on the yield distribution, fractional- and molecular-level chemical characteristic of volatile products obtained from the fast alkaline catalytic upgrading of OSB over calcium aluminate was carried out with the aid of the comparison with that over Y zeolite-based FCC catalyst and silica sand. The results revealed that three-phase products over calcium aluminate possessed the larger selectivity of C2−C4 alkenes, larger yield of light oil and the lower coke output, which were 51.88%, 45.49% and 7.96%, respectively. On basis of the chemical structure analysis of liquid products, the alkaline catalytic upgrading of OSB over calcium aluminate could heighten the content of chain alkyl structures as well as alkyl-substituents attached to aromatic ring in liquid products. This indicated that the fast heating rate and alkaline catalyst that adopted in catalytic upgrading process of OSB could play an energetic role in optimizing the composition of volatile products. The alkaline catalytic upgrading of OSB based on fluid pyrolysis technology with the fast heating rate could heighten the yield of low-carbon olefins and light oil and lessen coke yield, meanwhile modify the chemical structure characteristics of liquid products that were conducive to the generation of valuable chemicals (light alkanes and BTX) during secondary processing of liquid products.

Delayed response of bryophytes to wind disturbance and salvage logging in hemiboreal mixed forests

Climate change accompanied by altered natural disturbance regimes threatens the resilience of boreal and hemiboreal forests. Bryophytes, an important part of plant biomass and diversity, fulfill numerous important functions in forests, thus markedly contributing to the resilience of these ecosystems. We studied abundance, richness, diversity and community composition of bryophyte species 20–21 years after wind disturbance in moderately damaged, heavily damaged and heavily damaged and subsequently salvage-logged stands; overmature forest stands with similar tree species composition were included in the study as a reference group. The community characteristics were linked with treatment and accompanying environmental variables. Altogether, 108 bryophyte taxa (81 mosses and 27 liverworts) were identified in study plots. We found that bryophytes responded to windthrow severity level and salvage logging in terms of species richness, diversity, and composition; diversity of microhabitats was the most important environmental variable explaining the variation in diversity metrics. Besides exhibiting greater overall species richness, uncleared wind-disturbed plots contained more bryophyte species with high conservational value as well, compared to salvage-logged and control plots. The largest number of bryophyte taxa was associated with deadwood substrates. Ordination analysis further emphasized the importance of deadwood substrate for liverworts. In order to fulfill the objective of biodiversity conservation, wind-disturbed forests should be left to recover naturally, to ensure a favorable status of all naturally occurring species and to improve the status of endangered and rare species. Retaining a proportion of surviving and/or wind-damaged trees while salvaging might also alleviate the unfavorable environmental conditions for bryophyte species while “lifeboating” some species through the following successional stages.