Species Density Research Articles

A new optimization strategy, the influence of hollow electrode chamfers on the development of helium atmospheric pressure plasma jets

This work suggests applying chamfering treatment to the plasma generator of the empty electrode structure. Enhancing the electrodes’ physical structure can significantly improve plasma characteristics without requiring intricate control systems. Experiments have shown that changes in the electrode’s shape can lead to changes in the formation of the atmospheric pressure plasma jet. Specifically, our observations indicate that an increase in the chamfer radius leads to an increase in the ignition voltage and a greater density of reactive species inside the jet. We developed a multi-channel equivalent circuit model to describe the discharge process of a plasma jet. Then, using the mixed layer theory, we investigated the effect of the chamfer radius on the plasma jet. Our findings suggest that chamfering increases the effective discharge area, resulting in more discharge channels in the model. This leads to a higher density of reactive species. Additionally, chamfering improves the mixing of helium and air, increasing the concentration of N2 and O2. This consumes some of the avalanche electrons and raises the ignition voltages, ultimately enhancing the chemical reactivity of the plasma jet. This work provides new ideas for the optimization strategy of atmospheric pressure plasma radiation devices.

Mangroves and Associated Flora of Vashista Godavari Estuary from Darbharevu to Biyyaputippa, West Godavari District, AP, India

Mangrove ecosystem is one of the productive ecosystems in aquatic environment. Mangrove populations occurring along the Vashista branch of Godavari River were studied using line transect with 16 m² quadrates and the quadrate samples were analyzed. In the present investigation a total of 16 mangrove species were reported, out of which four are true mangrove species, six associated mangroves and six halophytes were reported. Transect studies revealed that mangroves were distributed up to 10 to 20 meters in Darbharevu and 30 to 40 meters in Biyyaputippa region. Most of the forest in Darbharevu is in form of long strip and in Biyyaputippa forest extends and density of species was high than Darbharevu. In both study sites (Darbharevu and Biyyaputippa) the species with the highest density was Suaeda monoica whereas the species with lowest density was Sonneratia caseolaris. The maximum height in these two stations varied from 5 to 10 meters only. Percentage frequencies of DBH (Density at Breast Height) classes were estimated. In the present study only two diameter classes in Darbharevu and 4 classes in Biyyaputippa were reported. This is an indicative of the small and bushy mangrove vegetation in station 1 and little bit larger canopy was reported in station 2. Anthropogenic and aqua industry play a critical impact on the survival of this mangrove ecosystems.

Assessing Microplastic Contamination in Shellfish: Insights from Pantai Remis Kuala Selangor, Strait of Malacca, Malaysia

Introduction: Microplastic (MP) contamination poses a global environmental threat, affecting terrestrial and marine ecosystems, and human health. This study investigates the presence, density, and composition of MPs in three commercially important shellfish species, oriental angel wing clam (Pholas orientalis), bamboo clam (Ensis leei), and blood cockles (Tegillarca granosa) at Pantai Remis Jeram, Kuala Selangor. Methods: Microplastics in shellfish were quantitatively analyzed for their abundance, colour, size, shape, and composition using microscopic techniques and micro-Fourier Transform Infrared (FTIR). Standard experimental protocols were followed. Statistical analysis of the data was performed using SPSS to identify correlations between these parameters. Results and Discussion: Our findings reveal a significant presence of MP particles in shellfish with T. granosa exhibiting the highest density (2.417 particles/cm³) compared to E. leei (0.721 particles/cm³) and P. orientalis (1.449 particles/cm³). Fibers and fragments were the dominant MP morphotypes, primarily in black color. P. orientalis and T. granosa contained a majority of MPs within the 1 - 5 mm size range, totalling 41 and 56 particles, respectively. Shellfish samples contain polymers of cellulase acetate and polyethylene terephthalate, indicating possible origins from plastic bottles and textile fibres. A statistically significant difference in the mean MP densities in the different species of shellfish was found by one-way ANOVA analysis (p = 0.042, p < 0.05). Conclusion: This study provides relevant data on MP pollution in commercially significant shellfish species. To effectively mitigate this environmental concern and comprehend the long-term ecological ramifications of MP intake by shellfish, more research is required.

Mesopredator release moderates trophic control of plant biomass in a Georgia salt marsh.

Predators regulate communities through top-down control in many ecosystems. Because most studies of top-down control last less than a year and focus on only a subset of the community, they may miss predator effects that manifest at longer timescales or across whole food webs. In southeastern US salt marshes, short-term and small-scale experiments indicate that nektonic predators (e.g., blue crab, fish, terrapins) facilitate the foundational grass, Spartina alterniflora, by consuming herbivorous snails and crabs. To test both how nekton affect marsh processes when the entire animal community is present, and how prior results scale over time, we conducted a 3-year nekton exclusion experiment in a Georgia salt marsh using replicated 19.6 m2 plots. Our nekton exclusions increased densities of plant-grazing snails and juvenile deposit-feeding fiddler crab and, in Year 2, reduced predation on tethered juvenile snails, indicating that nektonic predators control these key macroinvertebrates. However, in Year 3, densities of mesopredatory benthic mud crabs increased threefold in nekton exclusions, erasing the tethered snails' predation refuge. Nekton exclusion had no effect on Spartina biomass, likely because the observed mesopredator release suppressed grazing snail densities and elevated densities of fiddler crabs, whose burrowing alleviates soil stresses. Structural equation modeling supported the hypotheses that nektonic predators and mesopredators control invertebrate communities, with nektonic predators having stronger total effects on Spartina than mud crabs by controlling densities of species that both suppress (grazers) and facilitate (fiddler crabs) plant growth. These findings highlight that salt marshes can be resilient to multiyear reductions in nektonic predators if mesopredators are present and that multiple pathways of trophic control manifest in different ways over time to mediate community dynamics. These results highlight that larger scale and longer-term experiments can illuminate community dynamics not previously understood, even in well-studied ecosystems such as salt marshes.

Long‐Term Impacts of Selective Logging in a Tropical Rainforest in the East Region of Cameroon

ABSTRACTAlthough selective logging has become the primary cause of degradation in many African countries, little is known about its long‐term effects. This study investigated the long‐term effects of selective logging on forest tree species diversity and dynamics in the East Region of Cameroon. Six permanent monitoring plots of 1 ha each in unlogged and logged forests were established in 2005 and a recensus in 2011. Each 1 ha plot was divided into 25, 20 × 20 m quadrats. Each 20 × 20 m quadrat was further divided into 16, 5 × 5 m subquadrats, where the diameter at breast height (DBH) of all trees ≥ 2 cm was measured. There was a decrease in plant species density and richness in all forest types. Sloetiopsis usambarensis was the most important species in the unlogged forests and forests logged 21 years ago. The most important family was Putrangivaceae, Euphorbiaceae and Violaceae in the unlogged forests and forests logged 11 and 21 years ago, respectively. The frequency distribution of stem size classes indicated a reversed J‐shape of tropical forests. The above ground biomass (AGB) recovered more than 50% in all forests, and the unlogged forest had the highest AGB (961.8 Mg/ha). Larger stems indicated a forest at a stage of recovery from disturbance. Silvicultural management should be considered.

Diversity and Seasonal Variations of Zooplankton in Dudhiya Talab of Sirohi, India

In this study, the seasonal fluctuations of zooplankton and specific physico-chemical parameters were examined in Dudhiya Talab, a significant artificial reservoir located in Sirohi, Rajasthan. During the research period, a total of 41 zooplankton species were identified, comprising 12 species of Rotifera, 14 species of Cladocera, 5 species of Ostracoda, and 4 species of Copepoda. Among these, Rotifera emerged as the predominant group, with a peak abundance of 689 individuals per liter recorded in the summer, while the lowest numbers were noted during the winter season. Additionally, the zooplankton community exhibited correlations with various physico-chemical parameters. The findings of this research suggest that the distribution and density of zooplankton species are significantly affected by the prevailing physical and chemical conditions of the aquatic environment. Key words: Zooplankton, Physico-chemical factors,P Cladocera, Rotifera.

Significant role of secondary electrons in the formation of a multi-body chemical species spur produced by water radiolysis.

Scientific insights into water photolysis and radiolysis are essential for estimating the direct and indirect effects of deoxyribonucleic acid (DNA) damage. Secondary electrons from radiolysis intricately associated with both effects. In our previous paper, we simulated the femtosecond (1 × 10- 15s) dynamics of secondary electrons ejected by energy depositions of 11-19eV into water via high-energy electron transport using a time-dependent simulation code. The results contribute to the understanding of simple "intra-spur" chemical reactions of tree-body chemical species (hydrated electrons, hydronium ion and OH radical) in subsequent chemical processes. Herein, we simulate the dynamics of the electrons ejected by energy depositions of 20-30eV. The present results contribute to the understanding of complex "inter-spur" chemical reactions of the multi-body chemical species as well as for the formation of complex DNA damage with redox site and strand break on DNA. The simulation results present the earliest formation mechanism of an unclear multi-body chemical species spur when secondary electrons induce further ionisations or electronic excitations. The formation involves electron-water collisions, i.e. ionisation, electronic excitation, molecular excitation and elastic scattering. Our simulation results indicate that (1) most secondary electrons delocalise to ~ 12nm, and multiple collisions are sometimes induced in a water molecule at 22eV deposition energy. (2) The secondary electrons begin to induce diffuse band excitation of water around a few nm from the initial energy deposition site and delocalise to ~ 8nm at deposition energies ~ 25eV. (3) The secondary electron can cause one additional ionisation or electronic excitation at deposition energies > 30eV, forming a multi-body chemical species spur. Thus, we propose that the type and density of chemical species produced by water radiolysis strongly depend on the deposition energy. From our results, we discuss formation of complex DNA damage.

The impact of leftover herbicide residue applied to okra on weeds and crops of subsequent blackgram

In the present study, the impact of residual herbicide was studied from previous applications on okra plants, explicitly concerning the growth of weeds and subsequent black gram crops. The relative density of different weed species was determined, revealing that Echinochloa colonum had the highest density at 16.56% and 12.88%, followed by Leptochloa chinensis at 13.01% and Acrachne racemosa at 10.82%. However, within the group of sedges, Cyperus rotundus and Cyperus haspan had a greater relative density of 13.01% and 9.79%, respectively. The weed-free control treatment achieved the highest seed output of black gram, followed by two manual weeding on the 20th and 40th DAS. The herbicide residue resulted from application of metribuzin 500 g ha-1 on 3rd DAS, followed by post-emergence (POE) application of quizalofopethyl 50g ha-1 on 20 DAS recorded higher plant height 5.7%, dry matter production 32.7%, clusters plants-1 33.3%, pods plant-1 79.6%, grain yield 41.0%, halum yield 44.7%, nitrogen uptake 54.3%, phosphorus uptake 117.5%, and potash uptake 81.8% as compared to the weedy check.

Niche divergence mechanisms of closely related hybridising bird species. Modeling approach based on remote sensing data of forest habitats

Describing mechanisms that ensure stable co-occurrence of sympatric species is fundamental to understanding the complexity of ecological community dynamics. In this study, the Pied flycatcher and the Collared flycatcher were used as model species for the analysis of co-occurrence patterns of closely related hybridising species that inhabit overlapping forest habitats. I hypothesise that spatial niche partitioning between species emerges as a vital adaptive response to interspecific competition and manifests itself in significant shifts in habitat preferences in syntopic areas but not in the allotopic ones. The study leverages a comprehensive dataset that includes species density in 372 randomly selected 1 km² grid cells across the territory of Poland. The analysis of habitat preferences was performed with linear mixed-effect modeling, whereas a contrast analysis was used to investigate changes in habitat preferences resulting from the presence of a competitor. The findings indicate that both species modify their habitat preferences when transitioning between syntopic and allotopic sites. Remarkably, in regions without competitors, such shifts are significantly less pronounced, as demonstrated by the Pied flycatcher that prefers the same habitats both in allopatric regions and allotopic sites. When these results are compared with other studies on closely related hybridising and non-hybridising species, it turns out that what influences the degree and number of niches subjected to competition is the time that passes from species divergence. This study highlights the imperative need to incorporate co-occurrence parameters of closely related species into niche and species distribution models to enhance their ecological realism.

Altitudinal Variations of Ground Species in the Southern Aravalli regions of Rajasthan, India

Ground layer species sustain a variety of plants and animals; and maintain a healthy and resilient forest ecosystem by contributing to ecological functioning, structural support, and biodiversity. The western Indian Aravalli range is noted for its vegetation. Studies from these regions indicate that various environmental factors influence plant diversity and its distributions. The present study examines the impacts of altitude on ground species in Rajasthan's southern Aravalli hill ranges. We conducted field investigations year-round in Phulwari Ki Nal Wildlife Sanctuary, Kumbhalgarh Wildlife Sanctuary, and Sitamata Wildlife Sanctuary at different altitudes. A random transect method was used; five 1m2 plots were laid at every 250m interval. Species’ names and numbers were recorded from sampling plots. Sanctuary-wise species richness, density, and diversity were analyzed and related with altitude. The protected areas of Southern Aravalli do not follow an altitude-specific pattern in ground species distribution. Specific lower altitude ranges had the most species richness, density, and diversity. While altitude showed both positive and negative correlations with respect to ground species richness, diversity and density. The study findings help in conserving and preserving ground layer species in the Aravalli regions of Rajasthan.

Estimation of carbon stocks of woody plant species in church forests of West Gojjam zone, Northwestern Ethiopia: Implications for climate change mitigation

Forests, particularly church forests, play a crucial role in mitigating climate change by absorbing and storing CO2, preserving biodiversity, and acting as carbon sinks. This study aimed to estimate the biomass and carbon stocks of various woody species in church forests in the West Gojjam zone. Twenty-six church forests were selected based on agroecology, elevation, size, and proximity to population centers. Vegetation data were collected using a systematic sampling technique, with 20 m x 20 m (400 m2) plots established along transect lines oriented at 120° intervals at 60°, 180°, and 300° within each church forest. Measurements of diameter at breast height (DBH) and height were taken for all matured woody plants with a DBH ≥ 2.5 cm. Data analysis was performed using one-way ANOVA to evaluate the effects of altitude, forest size, and human disturbance on aboveground biomass (AGB) and carbon stocks. Additionally, linear regression was applied to investigate the relationship between vegetation structure (species richness, density, and diversity) and biomass accumulation. The results revealed a total of 111 woody species, dominated by indigenous species particularly from the Fabaceae family. The study church forests had Shannon diversity index and richness ranging from 1.73 to 3.47 and 7 to 45, respectively. The results showed that the 26 church forests had an average aboveground biomass (AGB) of 31.97 ± 3.31 tons ha-1 and a CO2 equivalence of 97.15 ± 10.47 tons ha-1. The AGB and aboveground carbon (AGC) values varied among the church forests, of which Debre Mihret Mesk Kidanemihret had the highest AGB with 99.00 tons ha-1 and 49.50 tons ha-1 AGC, indicating their substantial capacity for carbon storage. Conversely, Korch Silassie church forest displayed the lowest AGB, suggesting ecological challenges that necessitate targeted conservation efforts. These findings underscore the critical role of church forests as carbon sinks, capable of sequestering atmospheric CO2 and contributing to the mitigation of climate change. The findings of the present study suggest the integration of church forests into national and international climate policies, such as REDD+ to leverage their potential in reducing emissions from deforestation and forest degradation.

Checklists of extant harvestman (Arachnida: Opiliones) species for all the countries of the world

This study presents a comprehensive survey of the extant diversity of harvestmen (Arachnida: Opiliones), a pivotal taxon for biogeography and conservation studies, across Earth's geopolitical entities (here treated as "countries"). The rationale for recognizing more than 200 of these countries lato sensu worldwide is provided. The four most diverse of these countries are here further subdivided in states/provinces resulting in over 300 controlled vocabulary terms (geographic areas that contain harvestman records). These terms have been tagged to over 6900 species/subspecies of Opiliones, resulting in the generation of over 10,000 records. Checklists aiming for exhaustiveness are presented for valid extant Opiliones species/subspecies in each of these geographic areas, as documented in the World Catalogue of Opiliones (WCO) project, and geo maps are included to visually depict the distribution density of known species. Notably, this work marks the first-ever presentation of such checklists in the taxonomic literature for several countries, notably India, Indonesia, Papua New Guinea, and the Philippines. Brazil emerges as the most diverse country for harvestmen, with more than 1000 species, followed by Venezuela, Indonesia, and the United States, each hosting over 300 species. Checklists are individually provided for each state/province in these four countries. Elusive yet valid species are listed separately in their own section of nomina dubia, not entering the countries lists. Leiobunum rotundum argentatum Franganillo, 1926, is here elevated to Leiobunum argentatum Franganillo, 1926 new rank. Paropilio spinipes Roewer, 1956, is considered a junior subjective synonym of Opilio cirtanus C.L. Koch, 1839 syn. nov., Lacinius longisetus (Thorell, 1876) is considered a junior subjective synonym of Lacinius horridus (Panzer, 1794) syn. nov. The combination Rhopalocranaus hickmanni Caporiacco, 1951, is reinstated after this species appeared as Cranaus hickmanni in the literature. Some nomenclatural changes are established as a consequence of homonymy: (a) Paranemastoma graecum (Giltay, 1932) comb. nov. is the correct name for Nemastoma simplex Giltay, 1932 (currently combined as Paranemastoma simplex), a junior primary homonym of Nemastoma bacilliferum simplex Simon, 1913; (b) Belemulus annulatus remains permanently invalid as a junior secondary homonym replaced before 1961, so the replacement name to be used is Belemulus roeweri (Soares & Soares, 1948) comb. nov.; (c) Isaeus mexicanus Sørensen, 1932, must be reinstated as a species-group name rejected after 1960 due to secondary homonymy with Haehnelia mexicana Roewer, 1915; (d) Paranemastoma roeweri Staręga, 1978 is the correct name for Nemastoma redikorzevi Roewer, 1951, a junior primary homonym of Nemastoma redikorzevi Kharitonov, 1946; (e) the new name Neocynorta lanegra nom. nov. is proposed for Neocynorta lata (González-Sponga, 1992), originally Cynorta lata, which is a primary homonym of Cynorta lata Banks, 1909, currently in the genus Eucynortula; (f) the new name Neocynorta electrigena nom. nov. is proposed for Neocynorta punctata (González-Sponga, 2003), originally Paecilaema punctata, which is a primary homonym of Paecilaema punctata Sørensen, 1932, currently in the genus Anduzeia.

Water and nitrogen coupling regulates the present and future restoration trends under Spartina alterniflora invasion in a coastal salt marsh

Global change can easily cause the wetland ecosystem structure and function to be damaged by alien species. Former studies on Spartina alterniflora invasion only focused on the effect of aboveground communities, ignoring the potential regeneration of soil seed banks. Therefore, the study aimed to find the key resources that limit the S. alterniflora invasion and the regulation mechanism for S. alterniflora regeneration. Through investigating the S. alterniflora communities with different invasion stages, we studied the structure and composition of the aboveground communities and the soil seed banks, in response to the soil properties and water and nitrogen addition. The dominant competitive advantage of S. alterniflora was mainly affected by the aboveground biomass, which was regulated by soil NH4+-N and moisture content. Although the richness was same in the soil seed banks under the S. alterniflora communities with different coverage, S. alterniflora seeds maintained its specific competitive dominance. The niche breadth of S. alterniflora and the niche overlap between S. alterniflora and Tripolium pannonicum was the highest under low aboveground coverage. The soil seed bank germination experiments showed that the S. alterniflora density decreased when the soil nitrogen concentration exceeded 1 g/kg, while the density of native species E. crusgalli and T. pannonicum decreased when the water depth above the soil surface exceeded 2 cm. The successful naturalization of S. alterniflora invasion regulated by nitrogen-water coupling is a bet-hedging of the niche and fitness differences between invasive and native species in the coastal salt marsh of eastern China.

Density of Limnoperna fortunei larval stages in a cascade of subtropical reservoirs: spatiotemporal variation and environmental influences.

The golden mussel (Limnoperna fortunei) is an invasive bivalve that has established itself in several South American river systems, impacting ecosystem functioning. Reservoir cascades provide their larvae with the means of rapid dispersal, but the relationship between environmental variables and larval stage structure remains unclear. In this study, the density of three L. fortunei larval stages and quantitative detection using DNA are analyzed in a cascade of five reservoirs in the upper Uruguay River Basin and associated with spatiotemporal variation in environmental parameters. The analysis of L. fortunei eDNA presence and absence in freshwater systems appears to be a valuable mapping tool; however, no significant link was found between the eDNA magnitude and the overall larval density. The increase in larval density was related to the fluctuation of environmental parameters over a year, with the highest average larval densities observed in the CN and ITA reservoirs, though no significant difference was observed between the five reservoirs, where D-shaped larvae predominated. During winter, larval density decreased significantly, however, other variables also contribute to species activity and development in the upper Uruguay River Basin reservoirs and may be considered limiting factors. The relationships between environmental parameters were evaluated using a multivariate model. The interaction between reservoir area and precipitation, water temperature, electrical conductivity, and dissolved oxygen had a significant effect on larval density but showed specific influences on each larval stage. Any increase in density was regulated by dissolved oxygen and electrical conductivity content at all larval stages. Furthermore, total phosphorus affected the density of F1 and F3 larvae. The interaction between reservoir area and precipitation, nitrate content, phosphate concentrations, and water temperature had the most influence on the density of F2 and F3 larval stages; the F1 stage was mainly affected by calcium concentrations. The isolated effect of precipitation also contributed to the density of F2 and F3 larvae. Our findings shed light on the interaction between different phases of golden mussel larvae and the main nutrients found in reservoirs, which may be a determining factor in the rise in density of the non-native species in these systems.

Generating wildlife density data across Europe in the framework of the European Observatory of Wildlife (EOW)

Abstract The European Observatory of Wildlife EOW, as part of the ENETWILD project, represents a collaborative network that has been operating since 2021 to develop and implement standardized protocols to obtain harmonized data on distribution and density of target mammal species. In so doing, the EOW aims at contributing to improving the quality of data that are available for wildlife management and risk assessment on a European scale. This report describes the activities carried out during the 2023 EOW campaign, which was joined by a total of 30 organizations who committed to collect data in 44 sites across 22 different countries. We present data on the distribution and density of three species – wild boar (Sus scrofa), European roe deer (Capreolus capreolus), and red fox (Vulpes vulpes) – obtained by implementing a camera trapping protocol and by fitting the random encounter model (REM) for density estimation. Camera‐trap images were processed using the Agouti platform and some of its tools specifically designed for the management of camera trapping projects. This includes the use of photogrammetry to obtain parameters for the REM directly from the sequences of images. A total of 24 EOW sites were monitored in past years as well, providing multiannual density estimates and population trends and highlighting an improvement in the precision of the estimates, related to the improved study design and protocol implementation. We also describe the activities of the 2024 campaign, carried out as part of ENETWILD 2.0, where big efforts were made to expand the network, focusing on sites at risk of African Swine Fever, with wild boar/pig interactions and containing wetlands, as potential hubs for Avian Influenza. This effort resulted in the engagement of 40 participants monitoring 64 study sites (27 countries), including 28 study sites located either in infected areas or < 100km from the ASF frontline, and 25 sites with wetland habitats. Furthermore, in at least 20 sites pig farming is practised either intensively, extensively or as backyard farming. Finally, synergies were established with other international initiatives related to wildlife monitoring and disease prevention, with the aim of sharing experiences and sustaining a transnational data collection and harmonization.

The species diversity and phylogenetic structure patterns of desert plant communities in the Turpan-Hami region, Xinjiang

Desert plant communities play a crucial role in enhancing desert ecosystem productivity and stability but are highly susceptible to environmental changes owing to their limited resilience and resistance to disturbances, making it essential to understand the factors influencing their diversity patterns and community structure, particularly under the threat of climate change and intensifying droughts. This study focused on the Turpan-Hami desert region, a typical desert ecosystem in which diversity patterns and community structures remain unclear. We established 101 sampling sites ranging from elevations of -134 to 2056m and recorded community information, including species composition, height, coverage, and density, using the sample plot method. The diversity patterns were analyzed using regression analysis, and the phylogenetic structure was assessed. Additionally, Canonical Correspondence Analysis, Mantel tests, and General Linear Models were used to identify the key factors affecting community structure. Our results demonstrated that the species richness and phylogenetic diversity of plant communities exhibited a monotonic increase with elevation, and the phylogenetic structure exhibited low clustering and high dispersion along the elevational gradient. The annual mean temperature emerged as the most significant factor influencing diversity patterns, with soil nutrients, such as total potassium and available phosphorus, also affecting the spatial distribution of diversity. Notably, no significant correlations were found between community phylogenetic structure and abiotic factors, highlighting the complex interactions that drive diversity in the Turpan-Hami region. This study offers valuable insights into the mechanisms shaping desert plant community diversity and is essential for biodiversity conservation efforts in fragile desert ecosystems amid climate change.

Application of benthic foraminiferal indices to infer the ecological quality status in the Sepetiba Bay (SE Brazil)

The Sepetiba Bay (SB, SE Brazil) is a highly anthropized and industrialized area that has experienced severe environmental degradation in recent decades. This study applies a multiproxy approach to document the response of living benthic foraminifera to environmental stress and to infer the Ecological Quality Status (EcoQS) in SB. Our methodology involved a comprehensive comparison of the density and percentage of benthic foraminiferal species with physicochemical, textural, and geochemical data, specifically the concentrations of potentially toxic elements (PTEs). We also statistically compared two geochemical indices, the pollution load index (PLI) and the potential ecological risk index (PERI), with two ecological indices, the Tolerant Species Index (TSI) and the Exp(H'bc).The TSI and the Exp(H'bc) indices are significantly correlated with the environmental stressors in Sepetiba Bay, namely the PTEs concentrations (As, Cd, Pb, and Zn). The most tolerant species to the enrichment of PTEs and organic matter are Ammonia tepida (Cushman, 1926), Elphidium excavatum (Terquem, 1875), Ammonia buzasi Hayward and Holzmann, 2021 and Ammonia rolshauseni (Cushman and Bermúdez, 1946). The Exp(H'bc) and TSI reveal that most stations located in the inner zone and near the margins of the bay have poor and bad EcoQS, which agrees with the distribution of the environmental stressors.Thus, the current environmental conditions of the inner area of Sepetiba Bay are of great concern. This work also shows that using the TSI and the Exp(H'bc) indices, it is possible to classify EcoQS in transitional coastal environments in the North and South Atlantic transitional waters. This work has relevant scientific and social implications due to its importance in biomonitoring and the management of the coastal regions.

Carbon Absorption Potential in Sargassum sp. and Padina sp. in The Waters of East Melano Bay, Lemukutan Island, Bengkayang District, West Kalimantan Province

Increasing human activities have caused negative impacts on the environment, such as rising earth's surface temperature and extreme climate change. This impact is caused by increased greenhouse gas emissions such as carbon dioxide and methane. Marine vegetation such as seaweed Sargassum sp. and Padina sp. It can also help absorb carbon and reduce carbon emissions through the process of photosynthesis. Seaweed that has the potential to reduce carbon emissions is Sargassum sp. and Padina sp. which is located in the waters of East Melano Bay, Bengkayang Regency. This study aims to determine the density of seaweed species Sargassum sp. and Padina sp. in East Melano Bay, as well as analyzing the carbon sequestration potential of seaweed. The method used is to use the descriptive method of exploration. The descriptive method of exploration aims to describe the state of a phenomenon. This study uses the quadrant transect method in sampling in the field, while the determination of carbon content uses the analysis of biomass, ash content, moisture content and volatile substances. The results of the analysis that have been carried out show the density value of Sargassum sp. has the highest value of 102.4 Ind/m2 and Padina sp. 76.05 Ind/m2. Carbon sequestration by seaweed Sargassum sp. is 105,637 tons of C/ha and Padina sp. amounting to 78,032 tons of C/ha. Based on the description in this study, it can be concluded that the highest carbon absorption is in Sargassum sp.

Quarry rock reef design features influence fish assemblage structure across a systematically heterogenous restoration reef

To restore an area of temperate rocky-reef degraded by sedimentation, scour, and burial, a large quarry rock reef, the Palos Verdes Restoration Reef (PVR), was built with a heterogenous design including high relief elements intended to increase fish biomass productivity and support a diverse reef community. The replicated design features provide a unique opportunity to study the effects of reef design on fish habitat use patterns. To determine how submodule scale habitat features are associated with variation in the assemblage structure of eleven focal fish species on the PVR we conducted diver-operated stereo-video surveys on all 18 PVR modules 9–13 months after construction. The highest mean densities of most focal fish species and highest total fish densities were observed on high and medium-relief reef submodules and their adjacent ecotones positioned on the offshore sides or ends of modules. These included the most abundant species on the PVR, the zooplanktivorous Blacksmith (Chromis punctipinnis), as well as the fishery species Kelp Bass (Paralabrax clathratus) and California Sheephead (Bodianus pulcher). On the inshore side of parallel modules, the reef and ecotone transects on low and medium relief submodules exhibited the lowest total mean fish densities, and consistently lower mean focal fish species densities. Focal fish species assemblages also differed between the reef and sand-rock ecotone transects. Reef-resident planktivorous fishes likely contribute to reef primary and secondary productivity through consumer mediated nutrient transport and are an important consideration in restoration reef design. Future reef restoration designs should consider incorporating replicated heterogeneous design features including the placement of higher relief elements relative to shore and current patterns as a special consideration for providing habitat for planktivorous reef-resident fishes.

Enhancement of persistence in the rock-paper-scissors dynamics through higher-order interactions

Higher-order interactions (HOIs) are ubiquitous in real systems, and HOIs among individuals complicate the exploration of species diversity for populations in ecosystems. Therefore, understanding how higher-order interactions affect biodiversity is essential but poses significant challenges. In this paper, we consider higher-order interactions in the competitive processes of spatial rock-paper-scissors (RPS) dynamics, specifically within spatially embedded hyper-lattices, and investigate what biodiversity can be driven by HOIs. Considering hyperedges, species in hyperedges can be different, and different relationships are considered, which can eventually demonstrate the strength of competition. With the competition intensity modulated by the sensitivity of HOIs, extensive simulations have shown that higher-order competitive processes can promote coexistence. We also found that stratification of species densities occurs when three species coexist due to HOIs, which are closely related to the increase of empty sites and disordered spiral entanglement. From investigating the extinction probability in a broad aspect, it has been found that, even if HOIs are working, the coexistence in the system is eventually broken at high mobility regimes. The intensified sensitivity to HOIs can somewhat alleviate extinction, although no striking change has occurred. Our findings may address that modeling predator-prey interactions incorporating HOIs is important for gaining insights into biodiversity, and we hope our study may provide a broad aspect for exploring complex ecosystems.