Indicator Species Research Articles

Assessing the combined effects of catchment land use and runoff on estuarine fish assemblages

Connectivity between land and sea through the movement of species, energy and nutrients means that land-based impacts can affect the structure and functioning of nearby coastal ecosystems. As the interface between land and sea, estuaries are often faced with increasing pressures from catchment modifications (e.g. the removal of terrestrial vegetation) which can alter the overall health of estuaries (e.g. the degradation of coastal water quality due to an increase in terrestrial runoff) and change the value of habitat for many marine species. These landscape-scale impacts can, however, be mediated through variations in the context and connectivity of seascapes (e.g. greater extent of vegetated ecosystems help to filter nutrients). We surveyed fish across five estuaries over four years using underwater videography and sought correlations between fish biodiversity and abundance with variables indexing catchment land use, seascape connectivity, and coastal water quality. Fish assemblages were more abundant and diverse at sites which had lower chlorophyll-a concentrations and were nearer to the estuary mouth, in conjunction with catchments containing higher percent of natural land and heterogenous seascapes. Sites with lower concentrations of chlorophyll-a supported indicator species from more diverse functional groups that had greater fisheries values, in comparison to indicator species from sites with high concentrations of chlorophyll-a. This research can help direct coastal management to better prioritise management in coastal ecosystems, thereby enhancing fish richness and abundance, functional group richness and fisheries value.

Impact of environmental factors on small mammals and their fleas

Abstract Small mammals in the Horšianska dolina-Valley were researched first in 1984–86 and later in 2016–19. This paper seeks to identify and assess the species composition and dynamics of fleas (Siphonaptera) found in the valley on small mammals of Rodentia and Eulipotyphla and to compare findings from these two periods separated by thirty years. The results indicated deviations in small mammal and flea community similarity as well as in the small mammal indicator species for each habitat and flea indicator species for the small mammal species. A total 12 different species of small mammals were captured, and 12 flea species were collected. Eight flea species were detected in 1984–86 and ten species were found in 2016–19. In both periods A. penicilliger, C. assimilis, C. solutus, D. dasycnema, N. fasciatus were captured. The differences were that in the earlier period, the species uncovered were C. congener, P. bidentata, and P. soricis, while in the later period they were C. agyrtes, C. bisoctodentatus, M. turbidus, and R. integella. In the relationship between fleas and small mammals, C. solutus was the specific species for Apodemus flavicollis, while A. penicilliger and C. agyrtes were for Clethrionomys glareolus, and C. assimilis was for Microtus arvalis.

Genetic-environment associations explain genetic differentiation and variation between western and eastern North Pacific rhinoceros auklet (Cerorhinca monocerata) breeding colonies.

Animals are strongly connected to the environments they live in and may become adapted to local environments. Examining genetic-environment associations of key indicator species, like seabirds, provides greater insights into the forces that drive evolution in marine systems. Here we examined a RADseq dataset of 19,213 SNPs for 99 rhinoceros auklets (Cerorhinca monocerata) from five western Pacific and 10 eastern Pacific breeding colonies. We used partial redundancy analyses to identify candidate adaptive loci and to quantify the effects of environmental variation on population genetic structure. We identified 262 candidate adaptive loci, which accounted for 3.0% of the observed genetic variation among western Pacific and eastern Pacific breeding colonies. Genetic variation was more strongly associated with pH and maximum current velocity, than maximum sea surface temperature. Genetic-environment associations explain genetic differences between western and eastern Pacific populations; however, genetic variation within the western and eastern Pacific Ocean populations appears to follow a pattern of isolation-by-distance. This study represents a first to quantify the relationship between environmental and genetic variation for this widely distributed marine species and provides greater insights into the evolutionary forces that act on marine species.

Environmental DNA for monitoring the impact of offshore wind farms on fish and invertebrate community structures

AbstractTo reach the renewable energy targets set by the European Commission, a tenfold expansion of the installed offshore wind farms is needed. Since the construction of offshore wind farms may affect local soft‐sediment fauna, an efficient monitoring technique is needed to monitor the potential effects on the marine ecosystem. Here, we assess whether eDNA metabarcoding is a suitable alternative to monitor fish and epibenthos biodiversity in these difficult to access marine habitats. Water sampling and trawl surveys were conducted in parallel in 12 coastal and 18 offshore sites, the latter located inside and outside two offshore wind farms in the Belgian part of the North Sea. 12S eDNA metabarcoding retrieved 85.7% of the fish species caught in the beam trawls, whereas the COI eDNA metabarcoding only identified 31.4% of the epibenthic invertebrate species. Furthermore, the 12S marker resulted in an additional detection of 26 unique fish species, whereas the COI marker detected an additional 90 invertebrate species. Spatial patterns in alpha diversity recovered with eDNA metabarcoding were not significantly different from those observed with morphological determination. Significant differences were found in fish and invertebrate community structures between the coastal, transition and offshore zones as well as on the smaller wind farm scales, which agreed with the morphological beam trawl data. Indicator species found with morphological beam trawl monitoring for each of the three zones (coastal, transition, offshore) were also detected with 12S eDNA metabarcoding, and the latter method detected an additional 31 indicator species. Our findings show the need for adequate quality control of the obtained species lists and reveal that 12S eDNA metabarcoding analyses offers a useful survey tool for the monitoring of fish communities in offshore wind farms, but the used COI assay did not adequately capture the epibenthic communities as observed with beam trawl data.

Identification of Lutzomyia longipalpis' using MALDI-TOF peptide/protein profiles

Sand flies are vectors of great public health importance, since they constitute a group of hematophagous insects responsible for etiological agents transmission of zoonotic diseases such a visceral leishmaniasis. In face of the expansion of these diseases, efficient control strategies are needed which depend on comprehending the sand fly eco-epidemiology. In this regard, MALDI-TOF mass spectrometry has been used for bacteria, fungi and yeast detection studies through peptide/protein profiles. However, little is known about interference of biological factors associated with vector ecology, such as blood meal preferences and even sand fly age on the peptide/protein profiles. Thus, the present study aimed to evaluate the differences in peptide/protein profiles of the sand fly Lutzomyia longipalpis, by means of MALDI-TOF, due to the sand fly's age, sex, blood meal source and Leishmania infantum infection. Sample preparation was made removing both head and last abdomen segments keeping the thorax, its appendices and the rest of the abdomen. Five specimens per pool were used to obtain peptide/protein extract of which 1 μL solution was deposited over 1 μL MALDI matrix dried. Characteristic spectra were analyzed using principal coordinate analysis as well as indicator species analysis to discriminate differences in sand flies's peptide/protein profile by sex, age, blood meal source and L. infantum infection. The results show that the evaluated variables produced distinct peptide/protein profiles, demonstrated by the identification of specific diagnostic ions. It was found that the interference of biological factors should be taken into account when using the MALDI-TOF analysis of sand fly species identification and eco-epidemiological applications in field studies. Based on our results, we believe that it is possible to identify infected specimens and the source of blood meal in a collection of wild sand flies, serving to measure infectivity and understand the dynamics of the vector's transmission chain. Our results may be useful for epidemiological studies that look at the ecology of sand flies and leishmaniasis, as well as for raising awareness of biological characteristics’ impact on peptide/protein profiles in sand fly species identification.

Grasses don’t always win: Short-term effects of fertilization on taxonomic and functional diversity of a Mediterranean annual grassland

Nitrogen pollution has increased dramatically over the last decades, becoming a major contributor to biodiversity loss and compositional changes globally. While the main effects of excessive nutrients on plant communities are well established, Mediterranean grasslands have been less studied despite their high levels of biodiversity. Moreover, evidence has shown that the impacts of nutrients may depend on additional factors, namely soil conditions and grazing, increasing the uncertainty about the effects of increasing nutrient availability in these systems. In this work, we assessed the short-term effects (1 year) of fertilization in an extensively grazed oak open woodland (called montado, or dehesa), in Spain. Plots comprised a complete randomized design with four treatments: control (not fertilized), fertilization with nitrogen at a rate of 100 kg N ha−1, fertilization with phosphorous (50 kg P ha−1) and fertilization with both N and P (100 kg ha−1 N + 50 kg ha−1 P). We assessed changes in plant species composition and functional diversity and evaluated the association between species and fertilization treatments with an indicator species analysis. Our results showed that species diversity increased with NP fertilization and that forbs in particular increased in cover and richness. SLA and seed mass also showed differences compared to the control. The Community-weighted mean and functional dispersion of groups based on growth form and N-fixing ability were not influenced by fertilization. Two species were significantly associated with fertilized plots: the spiny forb Carlina racemosa and the latex-producing forb Tolpis barbata. Our study suggests that short-term fertilization may alleviate nutrient limitations in these systems, increasing plant diversity, although longer-term studies are needed to understand the effects of a continuous increase in nutrient availability.

Microbial community dynamics in a two-stage treatment wetland: Insights from treating seasonal ski resort wastewater

Microbial community studies in treatment wetlands (TW) have not investigated cold-climate TW and have focused primarily on laboratory mesocosms. This study determined microbial community composition and dynamics using 16s rRNA sequencing in a partially-saturated two-stage, vertical-flow pilot TW treating ski resort wastewater from December–April. Indicator species analysis found organisms capable of the primary nitrogen transformations observed in each stage at 3 °C, with nitrifiers in the unsaturated second stage and heterotrophic denitrifiers in the first stage where recycled nitrate is removed. During seasonal TW operation, microbial communities developed significant differences between TW stages and α-diversity decreased. Microbial communities were compared to batch mesocosm TW communities, which were significantly different from the pilot. The study is the first to discern community dynamics and key microorganisms during seasonal loading of a cold-climate, field-scale TW. Results raise questions regarding comparability of mesocosms to pilot systems and indicate more field-scale TW investigations are needed.

Integrated assessment of trace elements in a marine ranching area based on multi-species and multi-level biomarkers: a case study in China’s national-level marine ranching demonstration area

The goal of this study was to evaluate the trace element pollution in a marine ranching area in China based on molecular responses (expression of metallothionein and antioxidant enzyme genes), and biochemical biomarkers (metallothionein content, antioxidant enzyme activities, and malonaldehyde level) in four indicator species. We collected samples of two fish (Lateolabrax maculatus and Sebastes schlegelii), one crustacean (Charybdis japonica), and one gastropod (Rapana venosa) from the western Furong Island marine ranching area and from an adjacent area in March 2022 and measured the trace element content in these indicator species as well as in the seawater and sediment. We found that the bioaccumulation characteristics of trace elements and the response patterns of biomarkers were species specific. Moreover, not every biomarker was significantly correlated with environmental trace element content. We then established two biomarker combinations indicative of trace element pollution in seawater and sediment, respectively, based on the correlation between biomarkers and trace element contents. The selected biomarkers were integrated using integrated biomarker response version 2 (IBRv2). IBRv2 values in the studied marine ranching area were lower than those in the adjacent area. Additionally, these values were consistent with the bioaccumulation of trace elements in the indicator species, the integrated trace element pollution index for seawater, and the potential risk index for sediment. These results show that this multi-biomarker and multi-species IBRv2 approach provided a comprehensive diagnosis of trace element pollution in the marine ranching area. Therefore, its application may be beneficial for marine environmental monitoring and management in view of the ecotoxicological impact of pollutants on organisms.

Approaching a population‐level assessment of body size in pinnipeds using drones, an early warning of environmental degradation

AbstractBody mass is a fundamental indicator of animal health closely linked to survival and reproductive success. Systematic assessment of body mass for a large proportion of a population can allow early detection of changes likely to impact population growth, facilitating responsive management and a mechanistic understanding of ecological trends. One challenge with integrating body mass assessment into monitoring is sampling enough animals to detect trends and account for individual variation. Harbour seals (Phoca vitulina) are philopatric marine mammals responsive to regional environmental changes, resulting in their use as an indicator species. We present a novel method for the non‐invasive and semi‐automatic assessment of harbour seal body condition, using unoccupied aerial vehicles (UAVs/drones). Morphological parameters are automatically measured in georeferenced images and used to estimate volume, which is then translated to estimated mass. Remote observations of known individuals are utilized to calibrate the method. We achieve a high level of accuracy (mean absolute error of 4.5 kg or 10.5% for all seals and 3.2 kg or 12.7% for pups‐of‐the‐year). We systematically apply the method to wild seals during the Spring pupping season and Autumn over 2 years, achieving a near‐population‐level assessment for pups on land (82.5% measured). With reference to previous mark‐recapture work linking Autumn pup weights to survival, we estimate mean expected probability of over‐winter survival (mean = 0.89, standard deviation = 0.08). This work marks a significant step forward for the non‐invasive assessment of body condition in pinnipeds and could provide daily estimates of body mass for thousands of individuals. It can act as an early warning for deteriorating environmental conditions and be utilized as an integrative tool for wildlife monitoring. It also enables estimation of yearly variation in demographic rates which can be utilized in parameterizing models of population growth with relevance for conservation and evolutionary biology.

Leucojum vernum in Intorsurii Mountains (South- Eastern Carpathians)

This study investigates the population structure and ecology of the species Leucojum vernum (spring snowflake) in Întorsurii Mountains, South-Eastern Carpathians, where was supposed to be extinct. The research objectives were: (1) to identify the species in Popii Valley, (2) to estimate its population size, (3) to map the species extent, (4) to delineate the species ecological niche, (5) to identify and describe the vegetation types where the species grows, (6) to identify the co-occurring species as indicators of suitable habitat for L. vernum, and (7) to assess the species conservation status in Popii Valley and in Romania. Identification and description of the species population relied on an intensive survey in the whole watershed of Popii Valley. A detailed vegetation map of the Popii Valley watershed was created. For the description of the species habitat, 27 sampling plots were used. The species ecological preferences were drawn by means of the indicator species analysis, climate and geological maps. Climate suitability was checked by projecting the analyzed population in the bioclimatic envelope of L. vernum in Romania, using principal components analysis (PCA) ordination and classes of aridity index. The assessment of the conservation status followed the principles and methodological standards for monitoring protected species at the European Union and global level. In the studied area L. vernum was found in four forest associations, on moist and nutrient-rich soils. The indicator species of the suitable/unsuitable habitats were identified with the help of the phi coefficient of association between species. The population size and species habitat are in favorable conditions, although signs of bulbs collection for gardening were observed. These findings were discussed in a national and global context. An updated map for species extent in Romania was provided in order to support the assessment of the global and national IUCN category.

Directional succession and species-specific patterns observed in repeat study of vascular plants at three glacier foreland chronosequences in the Canadian High Arctic

This paper presents the first repeat study of glacier foreland chronosequences conducted in the Canadian High Arctic. Vascular plant species at three forelands on Ellesmere Island, Nunavut first surveyed in 1995 were resurveyed 21 years later to (1) test the original hypothesis that succession on these forelands was directional, and (2) investigate the use of the chronosequence method in High Arctic succession studies. Forelands were surveyed using percent cover estimates or presence/absence counts. Indicator species analysis and rates of change were used to quantify shifts. Total plant cover and species richness increased on younger terrain. Rates of peak cover and first appearance advance varied greatly between species and forelands, but were generally faster for graminoid and forb species than shrub species. We observed a pattern of directional succession at all three forelands, supporting the original hypothesis. However, species-specific patterns and rates of change acted to create assemblages that differed between 1995 and 2016, different successional trajectories were observed between the three forelands, and the first occurrence of most species was further from the glacier margin in 2016 compared to 1995. These results demonstrate the importance of repeat studies over time and replication over space to confirm observations in chronosequence studies.

Characteristics and Driving Mechanisms of Understory Vegetation Diversity Patterns in Central and Southern China

Large-scale forest restoration projects significantly reduce the net rates of forest loss. However, as a key component of forest restoration, planted forests have failed to restore biodiversity. China has implemented a large-scale afforestation program, which includes pure planted forests in particular, leading to various changes in ecosystem processes. Despite this, a comprehensive analysis of understory vegetation diversity patterns in these pure planted forests is still lacking. This study aimed to analyze the data on understory vegetation diversity from three typical pure and natural forest ecosystems of Hunan ecological forests to reveal their diversity patterns. The results revealed no significant difference in the understory diversity index between natural and pure forest types, although natural forests had a bigger species pool. The Zipf–Mandelbrot model was a better fit for species abundance distribution. The fitted results suggested that both environmental filtering and neutral processes affected the species abundance distribution and pure understory communities during restoration succession. Natural forests had the most stable understory diversity structure, whereas pure Phyllostachys heterocycla (Carr.) Mitford forests had the least stable structure. Multivariate regression tree analysis identified indicator species for each community. The gradient boosting model indicated that isothermality and slope direction were the most important factors affecting diversity. The β-diversity analysis showed that community establishment in the four forest types was affected via different mechanisms. The findings of this study have significant implications for understanding the impact of afforestation on the mechanisms for maintaining diversity.

Effects of nitrogen deposition on the rhizosphere nitrogen-fixing bacterial community structure and assembly mechanisms in Camellia oleifera plantations.

Increased nitrogen deposition is a key feature of global climate change, however, its effects on the structure and assembling mechanisms of the nitrogen-fixing bacteria present at the root surface remain to be elucidated. In this pursuit, we used NH4NO3 to simulate nitrogen deposition in a 10-year-old Camellia oleifera plantation, and set up four deposition treatments, including control N0 (0 kg N hm-2 a-1), low nitrogen N20 (20 kg N hm-2 a-1), medium nitrogen N40 (40 kg N hm-2 a-1) and high nitrogen N160 (160 kg N hm-2 a-1). The results showed that nitrogen deposition affected the soil nitrogen content and the structure of the nitrogen-fixing bacterial community. Low nitrogen deposition was conducive for nitrogen fixation in mature C. oleifera plantation. With increasing nitrogen deposition, the dominant soil nitrogen-fixing bacterial community shifted from Desulfobulbaceae to Bradyrhizobium. When nitrogen deposition was below 160 kg N hm-2 a-1, the soil organic matter content, total nitrogen content, nitrate nitrogen content, ammonium nitrogen content, urease activity, soil pH and nitrate reductase activity influenced the composition of the nitrogen-fixing bacterial community, but the stochastic process remained the dominant factor. The results indicate that the strains of Bradyrhizobium japonicum and Bradyrhizobium sp. ORS 285 can be used as indicator species for excessive nitrogen deposition.

Glutamic-N,N-Diacetic Acid as an Innovative Chelating Agent in Microfertilizer Development: Biodegradability, Lettuce Growth Promotion, and Impact on Endospheric Bacterial Communities

The search for new biodegradable fertilizers to increase the productivity of agricultural plants is an urgent task. In this study, a complex microfertilizer was developed based on a chelating agent—glutamic-N,N-diacetic acid (GLDA). The evaluation encompassed assessments of biodegradability and effectiveness in fostering lettuce plant growth in hydroponic and conventional soil settings. The impact on endospheric bacteria, a sensitive indicator, was also examined. Results indicated a 59.8% degradation rate of the GLDA complex on the 28th day. The most notable positive effects were observed in above-ground plant biomass, with a 4.6-fold increase for hydroponics and 1.5 to 1.8-fold increases for root and foliar treatments in soil. In hydroponics, GLDA-treated plants showed 24 and 45 operational taxonomic units (OTUs) for leaves and 272 and 258 for roots (GLDA-treated and control plants). In soil, the OTU counts were 270 and 101, 221 and 111, and 198 and 116 in the leaves and roots of GLDA-treated and control plants (under root and foliar treatments), respectively. Non-metric multidimensional scaling (NMDS) and Indicator Species Analysis (ISA) demonstrated significant distinctions in endospheric communities between substrates (hydroponics and soil) in the presence of GLDA. Importantly, GLDA use simplified the composition of endospheric bacterial communities.

Ant Communities (Hymenoptera: Formicidae) in a Protected Urban Park in Northeast Mexico

Introduction: The creation of protected natural areas within urban environments has played an essential role in providing small reservoirs of native vegetation and refuges for endemic species. Objective: To analyze, through ant communities, the influence of urbanization in a protected natural area (PNA) located in an urban zone. Methods: From April to July 2022, using bait traps and pitfall traps along 100 m transects, the presence of ant species was recorded in the El Refugio State Park Natural Area in Tamaulipas, Mexico. Alpha diversity was assessed using Hill numbers, while beta diversity was evaluated using the Jaccard index. Additionally, indicator species were identified through the indicator value (IndVal). Multiple correspondence analysis was conducted to associate the presence of species with environmental variables and vegetation types, and contingency tables were created to relate ant presence to vegetation cover size. Results: Species richness and diversity decreased in sites with low vegetation cover, such as in Tamaulipan thornscrub; moreover, secondary vegetation retained greater species richness. Indicator species were found in secondary vegetation and grassland areas, mainly composed of species that tolerate high temperatures and generalists such as Forelius mccooki and Tetramorium spinosum, while lowland jungle species were the only indicator species. The presence of these species is primarily associated with temperature, humidity, and vegetation cover. A significant relationship between the presence of ant species and vegetation cover size in El Refugio State Park was evident. Conclusion: The structure and composition of ant communities vary according to the type of vegetation structure, particularly in areas that have undergone greater anthropogenic damage. Therefore, the conservation of landscapes, as well as monitoring of these areas, should be considered in future research. Keywords: green areas; formicids; conservation; indicator species; community ecology.

Economic Evaluation of Water Management Alternatives in the Upper Green River Basin of Wyoming

Water use efficiency measures are generally recommended to reduce water use. Yet, flood irrigation practices in high-elevation mountain valleys of the Colorado River Basin headwaters generate return flows, which support late-season streamflow and groundwater recharge. Return flows support the ecosystem and provide recreational benefits. This study provides a framework for quantifying how land-use changes and associated return flow patterns affect the economic value of water across uses in a hydrologically connected, shallow alluvial aquifer system. This study first investigates how return flow patterns could change under three alternatives to flood irrigation: an increased use of center pivots, increased residential development, and conversion to pasture. The brown trout was used as an indicator species to track eco-hydrology, return flow, and capacity for recreational activities under each alternative. Estimates from the non-market valuation literature coupled with predicted changes in brown trout productivity approximate associated changes to recreational angler value. Recreational angler values are highest under the flood irrigation alternative. The inclusion of recreational angler values with agricultural values alters the magnitude of returns but not the rankings. These results highlight the potential heterogeneity of conclusions to be drawn regarding water use efficiency, depending on the economic value of water in different uses and the degree of hydrologic connectivity. This study also highlights data gaps and modeling needs for conducting similar future analyses.

Ecology of Elodea canadensis Michx. and Elodea nuttallii (Planch.) H. St. John-Insights from National Water Monitoring in Croatia.

Elodea canadensis Michx. (common waterweed) and Elodea nuttallii (Planch.) H. St. John (Nuttall's waterweed), two invasive aquatic plants from North America, have coexisted in European water bodies since the early 20th century. New localities for both species in Croatia continued to be discovered during a study that ran from 2016 to 2023 as a part of the annual implementation of Water Framework Directive monitoring that covered the entire territory of Croatia (786 sampling points in total). Based on these data, the distribution and ecology of both species were analysed. Elodea canadensis was found at 30 sampling points, mostly in rivers, and E. nuttallii at 15 sampling points, mostly in artificial canals. Nearly three-quarters (72.5%) of all elodea sampling points were in the Pannonian Ecoregion. Elodea canadensis was discovered for the first time in the Continental-Dinaric and Mediterranean-Dinaric Subecoregions. To study the ecology of the species, for each sampling point, vegetation relevés were performed and monthly measurements of physico-chemical parameters were collected. The most common accompanying species for both elodeas are presented, and the difference in species assemblages between the sites with E. canadensis and E. nuttallii was confirmed with the ANOSIM test. Furthermore, Indicator Species Analysis revealed eight species characteristic of E. canadensis sites and eleven species characteristic of E. nuttallii sites. Fitting multivariate models (CCA and NPMR) to species abundance revealed the ecological reaction of E. canadensis and E. nuttallii to environmental descriptors. The most strongly contributing environmental descriptors that influence the distribution of both Elodea species are biochemical oxygen demand, electrical conductivity and total phosphorus. In Croatia, the replacement of E. canadensis with E. nuttallii was observed in several water bodies with high nutrient loads.

Adaptive convergence and divergence underpin the diversity of Asteraceae in a semi-arid lowland region

Asteraceae is the most diverse family primarily found in semi-arid areas and species from the same botanical family have comparable phenotypes, occupy semi-arid habitats, and have adaptive convergences to environmental stress. Such characteristics aid in understanding adaptive radiations of recent groups on a regional scale and their successful establishment in habitats with challenging climatic and edaphic conditions. We investigated the adaptive convergence of the family as well as the fragile balance between fine-scale variation in adaptive traits and general convergence towards stress-tolerance and adaptation to aridity, using thorough field surveys and trait-based ecological approaches. Data was collected between 2020 and 2022 using the quadrat approach encompassed across 60 sites and five habitat types. Multivariate statistical methodologies were applied to analyze plant traits and soil variables. The tribes Cichorieae, Cardueae, and Heliantheae emerged as dominant contributors to the flora, illustrating their adaptability to varied ecological conditions. Microphyll emerged as the dominant leaf type, and therophytes prevailed as the most abundant life form. Urban habitats exhibited heightened sensitivity to Asteraceae species, as reflected in diversity indices. Canonical Correspondence Analysis demonstrated the significant influence of soil moisture, pH, phosphorus, and soil saturation on species distribution, with indicator species analysis highlighting habitat-specific plant-environment relationships. The study further classified species into adaptive strategies using CSR (competitive strategy-stress tolerant strategy-ruderal strategy) categorization. While some species exhibited pronounced R or S strategies, a majority demonstrated mixed strategies, such as R/CR, R/CSR, CS/CSR, emphasizing the versatility of adaptation strategies within the Asteraceae family. The findings underscore the intricate interplay between environmental variables and Asteraceae phylogenetic and functional diversity, highlighting the significance of soil properties in influencing plant distribution in semi-arid ecosystems. This research contributes valuable insights into the ecological dynamics of Asteraceae, shedding light on their responses to diverse environmental conditions and providing a nuanced understanding of the factors influencing their spatial distribution.

Metropolitan pressures: Significant biodiversity declines and strong filtering of functional traits in fish assemblages

Accelerating global urbanization is leading to drastic losses and restructuring of biodiversity. Although it is crucial to understand urban impacts on biodiversity to develop mitigation strategies, there is a dearth of knowledge on the functional structure of fish assemblages spanning the entire city-scale spectrum of urbanization intensity. Here, using environmental DNA sampled from 109 water sites in Beijing, we investigated the taxonomic and functional diversity patterns of fish assemblages across the city and uncovered community-, trait-, and species-level responses to various environmental stressors. By ranking sampling sites into three disturbance levels according to water physiochemical and landcover conditions, we found that both native and non-native fish taxonomic and functional α-diversity decreased significantly with elevating disturbance, as strong disturbance led to the disappearance of many species. However, the quantitative taxonomic and functional β-diversity components of native and non-native fish showed distinct patterns; assemblage turnover dominated native fish β-diversity and decreased with increasing disturbance, whereas species/trait richness differences dominated non-native fish β-diversity and increased with disturbance intensity particularly in lotic waters. RLQ and fourth-corner analyses revealed that fish size, fecundity, diet, and reproductive behaviors were significantly correlated with water quality, with pollution-tolerant, larger-sized native and omnivorous non-native fishes being urban winners, which indicates strong trait-dependent environmental filtering. Potential ecological indicator species were identified based on the sensitivity of fish responses to pollution loads; these were mostly small native species, and many have bivalve-dependent reproduction. Our results demonstrate that, along with native fish assemblage simplification and homogenization, urban stressors exert profound impacts on community trait composition, highlighting the need to consider both biodiversity loss and functional reorganization in combating disturbance of aquatic ecosystems under global urbanization. Furthermore, correlations between cropland cover and water nutrient level suggested that the management of agricultural runoff might be critically important for safeguarding urban water quality.

Assessing the ecological impact of beach tourism on crustacean abundance: a case study from West Coast of India

Sandy beaches are vulnerable to natural and anthropogenic disturbances like coastal hydrological disasters, coastal erosion, sea-level rise, pollution, and land degradation. Apart from these, at the habitat level, tourism and recreation activities impact the sandy beach ecosystem in countless ways. Several studies indicate that trampling caused due to human visitation negatively impacts the macrobenthic communities. In this study, along with the trampling effect, we assessed the impact of human visitation on the sandy beach ecosystem using factors like littering and human-induced predation pressure. The study was conducted on three sandy beaches in the Udupi district of Indian coastal state, Karnataka. We used human presence, predation pressure, and total litter as response variables; against sand crabs and ghost crabs as indicator species. The results indicated a significant correlation between response variables. Sand crabs were less affected by the human presence (r = 0.07, p = 0.14); however, ghost crab abundance was negatively influenced by human presence (r = − 0.36, p < 0.05), predation pressure (r = − 0.28, p < 0.05), and by litter presence (r = − 0.28, p < 0.05) at the beaches. We observed that human presence impacts sand crabs and ghost crabs directly (trampling) and indirectly (attracting human commensal predators through beach litter). We highlight the impacts of tourism on often neglected crab assemblages and emphasise the importance of deriving appropriate conservation measures for sandy beach ecosystems.