Affect Species Composition Research Articles

More the merrier? influence of mango orchards on the composition of the reptile communities of the lateritic plateaus, Maharashtra, India

AbstractChange in land‐use patterns affects a landscape by changing the composition of local flora and fauna. The lateritic plateaus in Konkan are one such example of this rapid land‐use change. Although these plateaus are rich in endemic flora and fauna, they are considered as “wastelands” due to lack of woody vegetation and thus, are subjected to various land‐uses. Mango cultivation in this region has become a major source of income due to its Alphonso variety of mangoes. Hence, over the last few decades, many plateaus have been converted into mango orchards. However, how the conversion of plateaus to mango orchards has affected species composition of different groups of organisms remains unclear. In the present study, we sampled the lateritic plateaus and plateaus converted into mango orchards in Ratnagiri, Maharashtra, to investigate the response of the reptile communities. We observed more species heterogeneity in the orchards compared to the unaltered sites. Moreover, it appeared that there was a species turnover when the plateaus were converted into orchards. The generalist and widespread species such as agamids and skinks and very few specialist species were comparatively more abundant in the orchards. On the contrary, the plateaus without orchards harbored more specialist species such as Hemidactylus albofasciatus (n = 62, in unaltered sites vs. n = 5 in the orchards), Echis carinatus (n = 15 in unaltered sites and none in the orchards) and Ophisops jerdonii (n = 45 in unaltered site vs. n = 12 in the orchards) compared to the generalist species.

Effects of isolation on invertebrate biodiversity among the bladderwrack Fucus vesiculosus

Geographic isolation is a factor that is known to affect species composition and diversity in marine systems. In this study, we tested the effects of geographic isolation on invertebrate fauna living among the belt-forming foundation species Fucus vesiculosus in the northern Baltic Sea. Sampling was carried out on reefs with varying levels of isolation (0.5, 1 and 2 km) in July 2021 in the Åland islands (between 59.96°N 20.24°E and 59.75°N 20.84°E). The total number of taxa, abundance, Shannon-Wiener index, Pielou’s evenness and biomass were calculated and the effects of isolation were tested using generalised linear models. Multivariate methods were used to analyse differences in the invertebrate community composition. Although the number of taxa and Shannon´s diversity index did not vary along the isolation gradient, the total abundance of fauna decreased with increasing isolation. In addition, some taxa-specific patterns were observed, e.g. the abundance of insect larvae decreased with isolation while isopods were more numerous in the most isolated locations. As diversity and the number of taxa were similar regardless of isolation, shallow Fucus vesiculosus belts likely act as important biodiversity refuges and potential stepping-stones for invertebrates in remote outer archipelago areas. In a changing climate, these kinds of refuges aiding species dispersal are likely to be even more important, and should be considered in conservation planning.

Dominance and rarity in tree communities across the globe: Patterns, predictors and threats

AbstractAimEcological and anthropogenic factors shift the abundances of dominant and rare tree species within local forest communities, thus affecting species composition and ecosystem functioning. To inform forest and conservation management it is important to understand the drivers of dominance and rarity in local tree communities. We answer the following research questions: (1) What are the patterns of dominance and rarity in tree communities? (2) Which ecological and anthropogenic factors predict these patterns? And (3) what is the extinction risk of locally dominant and rare tree species?LocationGlobal.Time period1990–2017.Major taxa studiedTrees.MethodsWe used 1.2 million forest plots and quantified local tree dominance as the relative plot basal area of the single most dominant species and local rarity as the percentage of species that contribute together to the least 10% of plot basal area. We mapped global community dominance and rarity using machine learning models and evaluated the ecological and anthropogenic predictors with linear models. Extinction risk, for example threatened status, of geographically widespread dominant and rare species was evaluated.ResultsCommunity dominance and rarity show contrasting latitudinal trends, with boreal forests having high levels of dominance and tropical forests having high levels of rarity. Increasing annual precipitation reduces community dominance, probably because precipitation is related to an increase in tree density and richness. Additionally, stand age is positively related to community dominance, due to stem diameter increase of the most dominant species. Surprisingly, we find that locally dominant and rare species, which are geographically widespread in our data, have an equally high rate of elevated extinction due to declining populations through large‐scale land degradation.Main conclusionsBy linking patterns and predictors of community dominance and rarity to extinction risk, our results suggest that also widespread species should be considered in large‐scale management and conservation practices.

Habitat structural complexity predicts cognitive performance and behaviour inwestern mosquitofish.

Urban stream syndrome alters stream habitat complexity. We define habitat complexity as the degree of variation in physical habitat structure, with increasing variation equating to higher complexity. Habitat complexity affects species composition and shapes animal ecology, physiology, behaviour and cognition. We used a delayed detour test to measure whether cognitive processes (motor self-regulation) and behaviour (risk-taking) of female Western mosquitofish, Gambusia affinis, varied with habitat structural complexity (low, moderate and high) that was quantified visually for nine populations. We predicted that motor self-regulation and risk-taking behaviour would increase with increasing habitat complexity, yet we found support for the opposite. Lower complexity habitats offer less refuge potentially leading to higher predation pressure and selecting for greater risk-taking by fish with higher motor self-regulation. Our findings provide insight into how habitat complexity can shape cognitive processes and behaviour and offers a broader understanding of why some species may tolerate conditions of urbanized environments.

Establishing grassland mixtures on mine wastes – a two-year mesocosm study

Plant growth on mine wastes is restricted by the lack of water, nutrients, phytotoxic responses and the absence of a seedbank. In a mesocosm study, we addressed the establishment of vegetation on metalliferous mine wastes from two seed mixtures. Besides the composition of the vegetation and the increase in plant cover and biomass over time, we studied concentrations of heavy metals in the shoot and analyzed the quantity of throughflow, its pH and EC to follow pollutant discharge. We hypothesized that the types of mine wastes and sown grasslands will affect species composition and the formation of a protective plant cover. Our platform was well-suited to study build-up and succession of a vegetation layer and its potential to stabilize mine wastes. However, the establishing community was less diverse than expected. The dilution of wastes increased species number and biomass, and we found a reduction of material discharge with increasing vegetation cover. Over time, drainage was reduced, while pH of the throughflow did not change. However, it was higher under the addition of greywater. Interestingly, the use of greywater led to a higher biomass in one mixture and slight changes in the chemistry of the throughflow and the plant matter.

Analysis and Functional Prediction of Core Bacteria in the Arabidopsis Rhizosphere Microbiome under Drought Stress.

The effects of global warming, population growth, and economic development are increasing the frequency of extreme weather events, such as drought. Among abiotic stresses, drought has the greatest impact on soil biological activity and crop yields. The rhizosphere microbiota, which represents a second gene pool for plants, may help alleviate the effects of drought on crops. In order to investigate the structure and diversity of the bacterial communities on drought stress, this study analyzed the differences in the bacterial communities by high-throughput sequencing and bioinformatical analyses in the rhizosphere of Arabidopsis thaliana under normal and drought conditions. Based on analysis of α and β diversity, the results showed that drought stress had no significant effect on species diversity between groups, but affected species composition. Difference analysis of the treatments showed that the bacteria with positive responses to drought stress were Burkholderia-Caballeronia-Paraburkholderia (BCP) and Streptomyces. Drought stress reduced the complexity of the rhizosphere bacterial co-occurrence network. Streptomyces was at the core of the network in both the control and drought treatments, whereas the enrichment of BCP under drought conditions was likely due to a decrease in competitors. Functional prediction showed that the core bacteria metabolized a wide range of carbohydrates, such as pentose, glycans, and aromatic compounds. Our results provide a scientific and theoretical basis for the use of rhizosphere microbial communities to alleviate plant drought stress and the further exploration of rhizosphere microbial interactions under drought stress.

Natural warming differentiates communities and increases diversity in deep-sea Ridge Flank Hydrothermal Systems

Ridge Flank Hydrothermal Systems have discrete pockets of fluid discharge that mimic climate-induced ocean warming. Unlike traditional hydrothermal fluids, those discharged by Ridge Flank Hydrothermal Systems have a chemical composition indistinguishable from background water, enabling evaluation of the effect of warming temperature. Here we link temperature and terrain variables to community composition and biodiversity by combining remotely operated vehicle images of vent and non-vent zone communities with associated environmental variables. We show overall differences in composition, family richness, and biodiversity between zones, though richness and diversity were only significantly greater in vent zones at one location. Temperature was a contributing factor to observed greater biodiversity near vent zones. Overall, our results suggest that warming in the deep sea will affect species composition and diversity. However, due to the diverse outcomes projected for ocean warming, additional research is necessary to forecast the impacts of ocean warming on deep-sea ecosystems.

Differences in Response of Tree Species at Different Succession Stages to Neighborhood Competition

Neighborhood competition influences tree growth, which can affect species composition and community succession. However, there is a lack of understanding regarding how dominant tree species at different successional stages of forest communities respond in terms of crown architecture and functional traits during their growth process to neighborhood competition. In this study, we analyzed the responses of average annual basal area increment (BAI), crown architecture, and leaf functional traits of early-successional species (Cunninghamia lanceolata and Pinus massoniana), transitional species (Alniphyllum fortunei and Choerospondias axillaris), and late-successional species (Elaeocarpus duclouxii and Castanopsis carlesii) to neighbor competition in a secondary evergreen broad-leaved forest. We found that the BAI of all species is negatively correlated with competition intensity. Notably, early-successional and transitional species exhibited a more rapid decline in growth rates compared to late-successional species in response to increased competition. Among these tree species, the response of crown structure to neighbor competition exhibited variation. Early-successional and transitional species displayed a negative correlation between the competition index and crown area (CA)/diameter, while a positive correlation emerged between the lowest branch height (LBH)/height. Conversely, late-successional species followed the opposite trend. In terms of leaf functional traits, specific leaf area (SLA) showed heightened sensitivity to neighborhood competition, with a positive correlation between SLA of all tree species and the competition index. Furthermore, water use efficiency (WUE) demonstrated negative correlations with the competition index in early-successional and transitional trees, while a positive correlation emerged with late-successional trees. These findings suggest that early-successional and transitional trees prioritize vertical canopy growth, whereas late-successional trees tend to favor horizontal canopy expansion in response to neighboring competition. Additionally, early-successional and transitional trees experience more significant suppression of radial growth rate. Our research contributes to a deeper understanding of the underlying mechanisms driving changes in species composition and community succession.

Plant-plant interactions influence post-fire recovery depending on fire history and nurse growth form

BackgroundsPlant-plant interactions are among the most important factors affecting the natural recovery of vegetation. While the impacts of nurse plants on species composition and biodiversity are well documented, the effects of different nurse’s growth forms on all biodiversity components including taxonomic, functional, and phylogenetic diversity have been less studied and compared, especially for their effects on different times after fire disturbance. This research was focused on comparing the effects of a perennial grass (Elymus hispidens), a perennial herb (Phlomis cancellata), and a high shrub species (Lonicera nummulariifolia) on species composition and the biodiversity components, and how these impacts change across five sites with short-term (1 and 4 years sites), long-term (10 and 20 years sites) times since last fire and a control site where no fire was known in recorded history in semi-arid shrublands of Fereizi Chenaran located in Northeast of Iran. The changes of species composition and taxonomic, functional, and phylogenetic diversity were calculated with respect to the presence/absence of nurse’s growth forms, fire history, and their interactions.ResultsNurse shrubs affected species composition and all biodiversity components, whereas all indices were reduced when considering Elymus grass as nurse plant. On the other hand, the herb Phlomis enhanced species composition and taxonomic diversity, while it had a negative effect on functional and phylogenetic diversity. Such specific effects of nurse types were mostly observed under long timescales (i.e., 10- and 20-year sites). Interestingly, the relative importance of nurse types and time since the last fire largely explained the variation of species composition and biodiversity components, with larger effects of nurse types on all biodiversity components. However, we found a significant contribution of fire explaining variation of species composition and phylogenetic diversity.ConclusionsThese results indicated nurse plants can affect the post-fire recovery of vegetation by providing specific mechanisms controlling beneficiary relatedness depending on their growth forms and time scales since the last fire. Therefore, these findings suggest perennial plants in the form of nurse species as a useful factor to develop techniques of active restoration in burned ecosystems.

Plant Allelopathy and Their Application in Gardens

The study of plant allelopathy is of extremely important research significance in agricultural and forestry production and management, as well as in ecological gardening applications in nature. Allopathies affects species composition in plant communities, It is one of the important factors affecting plant community succession. It is one of the important factors affecting plant community succession. In the application of garden landscape, the interaction and mutual restraint of communities are directly related to the final landscape effect. Therefore, by studying the effects of plants and garden applications, it is expected to provide reference value for garden landscape designers in the matching of garden landscape plants.

Influence of Elevation and Anthropogenic Disturbance on Woody Species Composition, Diversity, and Stand Structure in Harego Mountain Forest, Northeastern Ethiopia

Environmental variables like elevation affect species composition, diversity, distribution, density, and horizontal and upward growth. Ecologists are constantly working to better understand how species diversity varies along elevational gradients, particularly in mountainous ecosystems. Therefore, the purpose of this research was to examine the species’ horizontal and vertical structural diversity along the Harego Mountain Forest’s elevational gradient. The area was categorized into lower, middle, and upper elevations. A total of 67 (20 m × 20 m) plots were created along gradients of elevation 2,079–2,516 meters above sea level (m a.s.l.). Information for floristic composition, diversity, stand structure, and environmental variables were measured and recorded for each plot over the three elevational gradients. Data on anthropogenic disturbances were visually evaluated for every plot in every gradient of elevation. For the diversity analysis, Hill’s diversity statistics were employed. To find significant variations between the three elevational gradients in terms of Hill’s diversity number, stand structure, and environmental variables, the one-way analysis of variance with SPSS version 26 at the 0.05 level of significance was carried out. The finding revealed that 50 woody plants that belonged to 35 families and 44 genera in the 67 sample plots with an elevation of 2,079 to 2,516 were identified. Shrubs were dominant in each elevational gradient. Species richness, abundance, and Hill’s diversity number were all significantly ( p < 0.05 ) greater in the upper elevational gradient of the forest. On the other hand, all stand structures were significantly ( p < 0.05 ) higher in the middle elevational gradient. The effect of anthropogenic disturbances and environmental variables were clearly observed in the lower and upper elevational gradients than in the middle elevation. As a result, there were fewer seedlings, saplings, trees, and shrubs in the gradients of lower and higher elevations. For the conservation of the forest, it is crucial to pay special attention to biotic elements at lower elevations and abiotic factors at higher elevations. Accordingly, involving the local community in forest management, reducing anthropogenic pressure in and around the Harego Mountain Forest through tree planting in farmlands and woodlots and implementing physical soil and water conservation structures are recommended.

Habitat preference and diversity of bryophyte in the Jiulongshan National Forest Park, Eastern China

In densely populated, highly urbanized regions such as Zhejiang Province (eastern China), species are under enormous environmental pressures resulting from human activities, land use changes, and habitat fragmentation, which affect species composition and species diversity. Although eastern China is one of the most concentrated distribution areas of endemic bryophytes in East Asia, these species are also faced with the threats of habitat inadequacy. In order to get more information on bryophyte habitat and diversity, we investigated species composition, habitat preference, as well as species diversity differences of bryophytes under different habitat conditions in Jiulongshan National Forest Park (JNFP). In particular, the results showed that 108 specimens of bryophyte were collected in total, including 46 species in 32 genera of 21 families. Furthermore, we had found 12 species of bryophytes that had never been recorded before in Zhejiang Province. Remarkably, 40.74% of bryophytes were found to grow on natural rocks, followed by understories and roadside habitats. In addition, the Patrick richness index (R) varied most significantly among different habitats (p < 0.001). In a conservation perspective, natural rocks, roadways and understories should be preserved to protect bryophyte diversity.

Multidimensional beta-diversity across local and regional scales in a Chinese subtropical forest: The role of forest structure.

Beta-diversity, or the spatio-temporal variation in community composition, can be partitioned into turnover and nestedness components in a multidimensional framework. Forest structure, including comprehensive characteristics of vertical and horizontal complexity, strongly affects species composition and its spatial variation. However, the effects of forest structure on beta-diversity patterns in multidimensional and multiple-scale contexts are poorly understood. Here, we assessed beta-diversity at local (a 20-ha forest dynamics plot) and regional (a plot network composed of 19 1-ha plots) scales in a Chinese subtropical evergreen broad-leaved forest. We then evaluated the relative importance of forest structure, topography, and spatial structure on beta-diversity and its turnover and nestedness components in taxonomic, functional, and phylogenetic dimensions at local and regional scales. We derived forest structural parameters from both unmanned aerial vehicle light detection and ranging (UAV LiDAR) data and plot inventory data. Turnover component dominated total beta-diversity for all dimensions at the two scales. With the exception of some components (taxonomic and functional turnover at the local scale; functional nestedness at the regional scale), environmental factors (i.e., topography and forest structure) contributed more than pure spatial variation. Explanations of forest structure for beta-diversity and its component patterns at the local scale were higher than those at the regional scale. The joint effects of spatial structure and forest structure influenced component patterns in all dimensions (except for functional turnover) to some extent at the local scale, while pure forest structure influenced taxonomic and phylogenetic nestedness patterns to some extent at the regional scale. Our results highlight the importance and scale dependence of forest structure in shaping multidimensional beta-diversity and its component patterns. Clearly, further studies need to link forest structure directly to ecological processes (e.g., asymmetric light competition and disturbance dynamics) and explore its roles in biodiversity maintenance.

Importance of large-diameter conifer snags for saproxylic beetle (Cerambycidae) assemblages in old-growth remnants in Japan

ABSTRACT Conversion of old-growth forests to managed forests reduces the amount and variety of dead wood, particularly large snags (standing dead trees) are disappeared. Therefore, organisms that rely on large snags are considered to be severely affected by forest practices that convert old-growth forests to managed forests. We examined the effect of snag characteristics (diameter, bark cover, and decay gradient) on longicorn beetle (Cerambycidae) assemblages to search for species that prefer large-diameter snags in two old-growth remnants in a cool-temperate mixed forest and a sub-boreal conifer forest in Hokkaido, Japan. We collected beetles using window traps attached to conifer snags belonging to genus Abies and Picea and evaluated how snag characteristics affected beetles that feed on conifers with considering spatial autocorrelation. Species richness and total abundance were not associated with any of the snag characteristics. However, permutation tests in redundancy analysis revealed that snag diameter and bark cover affected species composition in the mixed forest, while only snag diameter had a significant effect in the conifer forest. Two (Macroleptura regalis and Prionus insularis insularis) and one (Sachalinobia koltzei) species preferred large-diameter snags in the mixed forest and the conifer forest, respectively. These species should be used as conservation targets to reduce the impacts of forest practices on saproxylic beetles. In contrast, one species (Molorchus minor fuscus) preferred small-diameter snags in the conifer forest. To conserve species that rely on large snags, we should maintain large snags in harvesting operations and retain large living trees for the future recruitment of large snags.

Deciphering the role of fungi in post-fire succession in Canada's Great Lakes–St. Lawrence forest region

Fungi are important drivers of forest health, as well as culturally important for many Indigenous communities. In Canada, increasingly intense and frequent wildfires affect fungal substrates and habitats, environmental conditions, and physiological responses of hosts with which fungi may interact. In Ontario, aggressive fire suppression raises the question of how fungal regeneration, and taxonomic compositions, may be affected when fires do appear on the landscape. This study investigates the fungal regrowth post-fire above and below-ground and the role fungal species play in post fire ecological succession in Southeastern Ontario. The study sites are two black oak savannas in restoration, previously prescribed a burn (Northumberland County, 2022 and 2023), and a recent wildfire burned mixed deciduous forest (Centennial Lake, 2023). We collected fruiting body and soil samples for fungal identification via observational and DNA methods. Above ground vegetation assays were made at 9 burned plots within these three sites and another 8 adjacent unburned (control) plots. We extracted soil DNA and will amplify fungal ITS2 amplicons by PCR. Then, we will sequence the amplified DNA using MiSeq to compare burned and unburned soil fungi. Lastly, we will use statistical methods to differentiate effects from fire and soil texture and type in burned and control plots. Thus far, we found that Pyropyxis rubra, a pyrophilous ascomycete fungus, is extremely abundant just weeks after the lightning-induced fire at Centennial Lake. Our combined observational and quantitative descriptions of above-and below ground soil fungi provide a deeper understanding of how fire affects species composition, fungal reproduction, and population dynamics in Ontario. This research may help inform other successional processes, and fungal harvesting of culturally important species.

Can diatoms be used as a biomonitoring tool for surface and groundwater? Towards a baseline for Karoo water

The environmental risks from shale gas extraction through the unconventional method of ‘fracking’ are considerable and impact on water supplies below and above ground. Since 2010 the recovery of natural shale gas through fracking has been proposed in parts of the fragile semi-arid ecosystems that make up the Karoo biome in South Africa. These unique ecosystems are heavily reliant on underground water, intermittent and ephemeral springs, which are at great risk of contamination by fracking processes. Diatoms are present in all water bodies and reflect aspects of the environment in which they are located. As the possibility of fracking has not been removed, the aim of the project was to determine if diatoms could be used for rapid biomonitoring of underground and surface waters in the Karoo. Over a period of 24 months, water samples and diatom species were collected simultaneously from 65 sites. A total of 388 diatom taxa were identified from 290 samples with seasonal and substrate variation affecting species composition but not the environmental information. Species diversity information, on the other hand, often varied significantly between substrates within a single sample. Analysis using CCA established that the diatom composition was affected by lithium, oxidized nitrogen, electrical conductivity, and sulphate levels in the sampled water. We conclude that changes in diatom community composition in the Karoo do reflect the water chemistry and could be useful as bioindicators.

Spatial scale affects the importance of deterministic and stochastic factors in the structuring of tadpole assemblages in Brazilian Cerrado

Many factors influence the structure of natural assemblages. Species interaction and environmental factors may generate deterministic patterns, whereas dispersal and ecological drift may generate stochastic patterns. We used pond systems to understand how deterministic and stochastic factors interact and influence tadpole assemblages at different spatial scales. We used variation partitioning and a co-occurrence analysis to evaluate how local environment heterogeneity, species interaction, and spatial variables affected species composition at local and regional scales in Brazilian savanna. Both deterministic and stochastic processes were important to explain tadpole distribution at regional scale, but with a greater contribution of stochastic factors. At local scales, environmental and niche traits were more important to explain tadpole distribution into the habitats. We demonstrate that in Brazilian Cerrado, species composition can be explained by the "MacArthur paradox", in which niche processes are important at local scales, whereas dispersal constraints and population processes lead to stochastic patterns in species distribution at large spatial scales.

Transmission Mode and Assembly of Seed Fungal Endophyte Communities in Wheat and Wheat Wild Relatives

Seeds acquire fungal endophytes either from the environment or from their progenitors. These transmission modes are central in shaping the microbiome because they affect species composition and balance. We studied fungal endophyte communities (FECs) in three plant species: bread wheat ( Triticum aestivum), wild emmer wheat ( Triticum turgidum dicoccoides), and wild barley ( Hordeum spontaneum). We conducted two experiments to test seed-to-seed transmission: (i) we compared FECs in stems and seeds collected from agricultural and natural habitats and (ii) we grew plants under greenhouse conditions to isolate the effect of vertical transmission on the plant FECs. The analysis of seed communities revealed differences in FEC composition and diversity among plant species; however, Alternaria infectoria dominated FECs in all plant species. In field-collected plants, the number of taxa in the seeds was less than half the number in stems, and close to 90% of the seed taxa were found in stems. The FECs from stems and seeds of greenhouse-grown plants were more diverse than the FECs of original seeds; they lacked a single dominant taxon, and the FECs in the new seeds had a similar richness and diversity to stem FECs, with only 40% overlap. The controlled-environment experiment confirmed vertical transmission of certain species but also showed that external infection of the seeds is the main source for specific taxa. Our results show that many taxa can reach the seeds internally, albeit in different abundance, that both infection sources affect seed FEC composition, and that external conditions affect the balance between FECs within the plant.

Coastal Fish Fauna in the Cystoseira s.l. Algal Belts: Experiences from the Northern Adriatic Sea

Cystoseira s.l. forests are recognised as important habitats which host diverse coastal fish assemblages. Many fish species use such habitats as feeding, breeding, and nursery grounds. Since the coastal fish community depends on the availability of dense macroalgal belts, the decline of these habitats in the Mediterranean Sea also affects the density of coastal fish species. We studied the coastal fish assemblage in Cystoseira s.l. forests in three consecutive years 2019–2021 in the Gulf of Trieste (Adriatic Sea). Data on coastal fish fauna were collected by visual counts conducted by SCUBA diving. Data on algal cover and habitat types were obtained by recording with a video camera. Similarities and differences in the fish community were analysed in terms of habitat and substrate preferences. A total of 34 species were recorded in Cystoseira forests. The results of the present study show that the different algal cover and associated depth gradient have different effects on the fish assemblage in coastal waters, affecting species composition and abundance. For many species, particularly labrids and sea breams, there is a decreasing temporal trend in frequency of occurrence and density. However, fish community trends can be used as a good “proxy” to evaluate the algal belt status. Our results indicate that rapid conservation and restoration actions are needed to stem the decline of Cystoseira s.l. forests.

Shoreline hardening affects species composition and condition of larval fishes in the Yangtze River: Implications for conservation and inshore habitat restoration

AbstractInshore habitats play a crucial role in the downstream drift of larval fish in large rivers. Natural inshore habitats of most of the world's large rivers have been heavily degraded by shoreline stabilization measures, but the knowledge about consequences for the condition and distribution of larval fishes is extremely limited. Investigations during the peak season of larval drift into species composition as well as into feeding intensity and body injuries of representative taxa were conducted at different inshore mesohabitats along semi‐natural and stabilized shores in a free‐flowing section in the middle Yangtze River. Species were unambiguously identified by a combination of DNA barcoding and morphological analyses. Overall, 37 taxa from seven families were detected from a total of 9,915 fish larvae caught. Earlier developmental stages greatly outnumbered the later stages in diversity and abundance in each investigated mesohabitat. Abundance and assemblage structure as well as the body injury rate differed significantly between mesohabitats. Generally, overall species richness and abundance tended to be lower, and divergence of the assemblage and body injury rates tended to be higher at heavily hardened shores, which could be contributed to the poor riparian vegetation and restricted suitable hydraulic conditions there. Our results may reflect the underestimated impact of inshore habitat degradation on larval fishes and highlight the demand for creating adequate areas of shallow and slow‐flow habitats with good riparian vegetation conditions along the shores. These measures will foster an appropriate connectivity between spawning areas and high‐quality nurseries for larval fishes.