Effective Number Of Species Research Articles

Resistance and Resilience of Species Composition: Thirty Years of Experimental Mismanagement and Subsequent Restoration in a Species Rich Meadow.

Traditionally managed grasslands are among the most species-rich communities, which are threatened by land use changes-management intensification or abandonment. The resistance of their species composition to mismanagement and ability to recover after re-establishment of traditional management is of prime conservational interest. In a manipulative experiment in a wet meadow, we simulated mismanagement by a factorial combination of abandonment of mowing and fertilization. The dominant species Molinia caerulea was removed in half of the plots to assess its role in community dynamics. The 21 years' mismanagement period was followed by the re-establishment of the traditional management. The plots were sampled yearly from 1994 (the baseline data, before the introduction of the experimental treatments), until 2023. Estimates of cover of all vascular plant species provided the species richness and effective number of species. For each year, the chord distances to baseline species composition and to corresponding control plot were calculated. The compositional data were analyzed by constrained ordination methods, and the univariate characteristics by Repeated Measures ANOVA. All the plots, including those with traditional management throughout the whole experiment, underwent directional changes, probably caused by a decrease in groundwater level due to global warming. Both fertilization and abandonment led to a loss of competitively weak, usually low-statured species, due to increased asymmetric competition for light. The effect of fertilization was faster and stronger than that of abandonment demonstrating weaker resistance to fertilization. The removal of dominant species partially mitigated negative effects only in unmown, non-fertilized plots. The recovery following mismanagement cessation was faster (signifying higher resilience) in unmown than in fertilized plots, where it was slowed by a legacy of fertilization. In a changing world, two reference plot types are recommended for assessment of resistance and resilience, one original state and one reflecting compositional changes independent of treatments.

Fiducial-cosmology-dependent systematics for the DESI 2024 BAO analysis

When measuring the Baryon Acoustic Oscillations (BAO) scale from galaxy surveys, one typically assumes a fiducial cosmology when converting redshift measurements into comoving distances and also when defining input parameters for the reconstruction algorithm. A parameterised template for the model to be fitted is also created based on a (possibly different) fiducial cosmology. This model reliance can be considered a form of data compression, and the data is then analysed allowing that the true answer is different from the fiducial cosmology assumed. In this study, we evaluate the impact of the fiducial cosmology assumed in the BAO analysis of the Dark Energy Spectroscopic Instrument (DESI) survey Data Release 1 (DR1) on the final measurements in DESI 2024 III. We utilise a suite of mock galaxy catalogues with survey realism that mirrors the DESI DR1 tracers: the bright galaxy sample (BGS), the luminous red galaxies (LRG), the emission line galaxies (ELG) and the quasars (QSO), spanning a redshift range from 0.1 to 2.1. We compare the four secondary AbacusSummit cosmologies against DESI's fiducial cosmology (Planck 2018). The secondary cosmologies explored include a lower cold dark matter density, a thawing dark energy universe, a higher number of effective species, and a lower amplitude of matter clustering. The mocks are processed through the BAO pipeline by consistently iterating the grid, template, and reconstruction reference cosmologies. We determine a conservative systematic contribution to the error of 0.1% for both the isotropic and anisotropic dilation parameters α iso and α AP. We then directly test the impact of the fiducial cosmology on DESI DR1 data.

Butterfly Diversity and Community Dynamics in the Central Himalayas: Species Composition, Richness, Abundance, and Seasonal Variation of Butterflies (Lepidoptera: Papilionoidea) in Bhorletar, Nepal.

Butterflies are among the most effective bioindicators of climate change; however, their diversity in many rural areas of the Central Himalayas remains understudied. This study provides an assessment of butterfly diversity in the foothills of Bhorletar, Madhya Nepal Municipality, Lamjung District, Nepal, within an elevation range of 420-600 m. Conducted between July 2019 and January 2021, the survey involved opportunistic observations and photography of adult butterflies in their natural habitats, with sampling occurring six times each month. The study aimed to investigate the species composition, richness, and abundance of butterflies across the survey period and identify seasonal changes in species composition and richness. A total of 94,009 individuals across 226 species, 129 genera, and six families were documented. During this study, Halpe arcuata Evans, 1937 and Hasora taminatus bhavara Fruhstorfer, 1911 were recorded for the first time in Nepal. Additionally, Halpe filda Evans, 1949 and Ctenoptilum vasava vasava (Moore, [1866]) were recorded for only the second and third times, respectively, in Nepal, following a gap of approximately three decades. The most abundant species was Pieris canidia indica Evans, 1926 (Relative Abundance [RA] 2.55%), followed by Pseudozizeeria maha maha (Kollar, [1844]) (RA 2.13%). Species richness showed an annual bimodal distribution, peaking in April (180 species) and August (161 species), while the lowest richness was observed in January and February, with 68 and 75 species, respectively. Diversity indices included a Shannon-Wiener index of 4.71, Pielou's J index of 0.87, an effective number of species of 111.24, and Margalef's richness index of 19.65, indicating high species diversity with a well-balanced mix of species evenness and richness. This study offers the first peer-reviewed checklist of butterflies from Bhorletar, providing crucial baseline data for future research and conservation efforts, and highlights the remarkable seasonal and species diversity within the region.

Impact of the COVID-19 Pandemic on Microbial Profiles and Clinical Outcomes in Orbital and Preseptal Cellulitis.

Orbital cellulitis and severe preseptal cellulitis are critical periocular infections with potential vision- and life-threatening implications. The COVID-19 pandemic is hypothesized to have had an influence on their presentation and pathogenesis; however, the real impact remains unclear. In this retrospective multicenter cohort study from January 2017 to December 2022, we analyzed 1285 cases with preseptal or orbital cellulitis in pre-pandemic (2017-2019) and pandemic (2020-2022) cohorts. A notable decrease in hospitalized cases during the pandemic period was observed (97 patients in the pre-pandemic group vs. 54 in the pandemic group, p = 0.004), particularly among individuals aged 30-39 (p = 0.028). Sinusitis remained the leading cause, but odontogenic cases increased (p = 0.025). In addition, microbial diversity decreased during the pandemic, with the effective number of species decreasing from 17.07 to 8.87, accompanied by a rise in antibiotic resistance, notably against erythromycin, oxacillin, penicillin, and metronidazole. While visual outcomes appeared worse in the pandemic group, statistical significance was not reached. These findings suggest that the characteristics, etiology, microbial profiles, resistance patterns, and visual outcomes of orbital and preseptal cellulitis have undergone alterations post-COVID-19 pandemic. Vigilance in clinical management and public health measures is crucial, with further research needed to optimize treatment strategies.

Temporal Dynamics of Species Richness and Composition in a Peri-Urban Tropical Frog Community in Central Brazil.

Analyzing the temporal dynamics of ecological communities can shed light on coexistence mechanisms and help understand how populations and communities will behave in the face of climate change. However, little is known about how frog communities respond to climate in urban ecosystems, especially in tropical countries. Here, we analyzed how frog species richness and abundance are influenced by weather variables both intra- and inter-annually. We surveyed a peri-urban area in central Brazil, monthly for 3 years. To test the effect of weather variables on species richness and abundance, we used Generalized Additive Mixed-effects Models. We assessed seasonality using circular statistics. We also tested for differences in temporal beta diversity within and among years by estimating species disappearance and temporal rank shift, in addition to a multivariate model-based method to test the effect of year on species composition. Finally, we tested how taxonomic and phylogenetic alpha diversity changed through time using a novel approach based on Hill numbers. We found that species richness varied little among years and was affected only by photoperiod, while species abundance was more variable both between and within years, being mostly affected by humidity, temperature, and photoperiod. Species composition varied little between years, mostly between the first and subsequent years. Conversely, beta diversity was highest within years. Only the effective number of species changed significantly through time. Our results help not only understand temporal mechanisms that allow species coexistence, but also allow to make inferences about the impact of urbanization on biodiversity in recently urbanized landscapes, showing that species composition in peri-urban sites remains unaltered in a mid-timescale, especially when climate conditions change little across years.

Rapid SARS-CoV-2 surveillance using clinical, pooled, or wastewater sequence as a sensor for population change.

The COVID-19 pandemic has highlighted the critical role of genomic surveillance for guiding policy and control. Timeliness is key, but sequence alignment and phylogeny slow most surveillance techniques. Millions of SARS-CoV-2 genomes have been assembled. Phylogenetic methods are ill equipped to handle this sheer scale. We introduce a pangenomic measure that examines the information diversity of a k-mer library drawn from a country's complete set of clinical, pooled, or wastewater sequence. Quantifying diversity is central to ecology. Hill numbers, or the effective number of species in a sample, provide a simple metric for comparing species diversity across environments. The more diverse the sample, the higher the Hill number. We adopt this ecological approach and consider each k-mer an individual and each genome a transect in the pangenome of the species. Structured in this way, Hill numbers summarize the temporal trajectory of pandemic variants, collapsing each day's assemblies into genome equivalents. For pooled or wastewater sequence, we instead compare days using survey sequence divorced from individual infections. Across data from the UK, USA, and South Africa, we trace the ascendance of new variants of concern as they emerge in local populations well before these variants are named and added to phylogenetic databases. Using data from San Diego wastewater, we monitor these same population changes from raw, unassembled sequence. This history of emerging variants senses all available data as it is sequenced, intimating variant sweeps to dominance or declines to extinction at the leading edge of the COVID-19 pandemic.

Habitat loss and simplification lower arthropod richness but not diversity

AbstractHabitat loss is rarely truly random and often occurs selectively with respect to the plant species comprising the habitat. Such selective habitat removal that decreases plant species diversity, that is, habitat simplification or homogenization, may have two negative effects on other species. First, the reduction in plant community size (number of individuals) represents habitat loss for species at higher trophic levels who use plants as habitat. Second, when plants are removed selectively, the resulting habitat simplification decreases the diversity of resources available to species at higher trophic levels. It follows that habitat loss combined with simplification will reduce biodiversity more than habitat loss without simplification. To test this, we experimentally implemented two types of habitat loss at the plant community level and compared biodiversity of resident arthropods between habitat loss types. In the first type of habitat loss, we reduced habitats by 50% nonselectively, maintaining original relative abundance and diversity of plant species and therefore habitat and resource diversity for arthropods. In the second type of habitat loss, we reduced habitats by 50% selectively, removing all but one common plant species, dramatically simplifying habitat and resources for arthropods. We replicated this experiment across three common plant species: Asclepias tuberosa, Solidago altissima, and Baptisia alba. While habitat loss with simplification reduced arthropod species richness compared with habitat loss without simplification, neither type of habitat loss affected diversity, measured as effective number of species (ENS), or species evenness as compared with controls. Instead, differences in ENS and evenness were explained by the identity of the common plant species. Our results indicate that the quality of remaining habitat, in our case plant species identity, may be more important for multi‐trophic diversity than habitat diversity per se.

Second-growth forests of the Mexican tropics are reservoirs of timber species similar to old-growth forest: Perspectives for sustainable forest management

Second-growth forests represent the largest area of forest in southern Mexico and can provide relevant information on how their structural attributes in are linked to anthropogenic factors and for their forest management. However, a knowledge gap remains at national level with little scientific literature available. Therefore, this research aimed to investigate the structure and tree richness of second-growth forests in the south of Quintana Roo State, México. With stratified sampling through participatory mapping of local collaborators, secondary tropical forests of 7, 15, 27, 37, and ≥ 48 to 80 years (y) old-growth were identified. We categorized forests into three successional stage classes: 5-20 y (Class I; forests of 7 and 15 y); 25-40 y (Class II; forests of 27 and 37 y), and old-growth forest (Class III; forests 48-80 y). In each forest (7, 15, 27, 37, 48, and 80 y of time since abandonment [tSA]) three plots were randomly chosen and established within the forest. Each age class was composed of two forests and six sample plots. In total there were 18 plots of 500 m2 each. Subsequently, we: i) calculated the land use intensity (LUI) to which the sites were subjected, ii) described the following structural attributes: floristic similarity, true diversity (effective number of species), stem density, and basal area (AB), and iii) evaluated if tSA and LUI influence the aforementioned structural attributes. Tree diversity was characterized with Hill numbers associated with observed species richness (0D), richness of equally abundant species (1D), and dominant species (2D). Forest structure was analyzed by density (number of trees ha−1) and distribution of stems by diameter class ha−1 and basal area (BA, m2 ha−1). The second-growth forest was derived from the milpa agricultural system under moderate land use intensity (LUI index = 0.02 - 0.1). Floristic structure was at least similar between Class I and Class III. Forest age and LUI do not affect tree composition of the forests (p ≥ 0.1667). However, these two factors affected stem density and BA. Only the species richness (0D) of second-growth forest and old-growth forest was influenced by tSA (p = 0.0002). In second-growth forests, Classes I and II, 78 species (0D) were recorded, 8 and 8 exclusive species, 28 and 36 equally abundant species (1D), and 15 to 24 dominant species (2D). In the old-growth forest, Class III, 70 species were recorded, and 38 and 26 equally abundant (1D) and dominant species (2D), as well as 5 exclusive species. The density of stems decreased with increasing forest age and increasing BA. Second-growth forest and old-growth forest all showed a high density of small diameter stems. These results indicate that second-growth forests are important tree species reservoirs (including those for timber purposes), comparable to old-growth or mature forests, and therefore they are relevant not only as biodiversity conservation areas or carbon sinks, but also for planned sustainable forest management.

Changes in floristic and vegetation structure in a chronosequence of abandoned gold-mining lands in a tropical Amazon forest

This study analyzes floristic and vegetation structure changes during forest succession after disturbances caused by small-scale gold mining in Madre de Dios (Peru). We compared the floristic and vegetation structure of a reference forest against three sites with different periods of abandonment after mining (5, 11 and 23-years). Three 20 × 60 m plots were defined on each site, and all tree species with a DBH >1 cm within the plots were inventoried. To evaluate species diversity and similarity, the Importance Value, effective numbers of species (0D, 1D, and 2D), and Chao-Jaccard similarity index were calculated. We used the Nonmetric multidimensional scaling for similarity ordination and the PERMANOVA test to evaluate differences in floristic composition. We recorded 129 tree species in the study areas and statistically significant differences between initial and intermediate stages were observed regarding floristic composition, basal area, height, and DBH. The transition from the initial successional stage to the reference forest produces an increase in basal area, species diversity, and floristic similarity. The 23-year-old stand had more species in common with the 11-year-old stand than the reference forest. Our results showed a high proportion of pioneer species and anemochory dispersal syndrome in the initial successional stages, but they decreased in later stages of the chronosequence. The floristic and structural attributes of forests throughout the chronosequence showed a fast recovery during secondary succession. After 23 years, the recovery of tree species density was 77 % of reference forest, while the relative recovery of species composition was much slower, on average 23 %. These results provide essential information to guide the selection of suitable species in ecological restoration projects after abandonment. Implementing forest restoration strategies based on reliable information to accelerate the process of vegetation succession is critical for recuperating areas degraded by gold mining at the Peruvian Amazon.

Coherent response of zoo‐ and phytoplankton assemblages to global warming since the Last Glacial Maximum

AbstractAimWe are using the fossil record of different marine plankton groups to determine how their biodiversity has changed during past climate warming comparable to projected future warming.LocationNorth Atlantic Ocean and adjacent seas. Time series cover a latitudinal range from 75° N to 6° S.Time periodPast 24,000 years, from the Last Glacial Maximum (LGM) to the current warm period covering the last deglaciation.Major taxa studiedPlanktonic foraminifera, dinoflagellates and coccolithophores.MethodsWe analyse time series of fossil plankton communities using principal component analysis and generalized additive models to estimate the overall trend of temporal compositional change in each plankton group and to identify periods of significant change. We further analyse local biodiversity change by analysing species richness, species gains and losses, and the effective number of species in each sample, and compare alpha diversity to the LGM mean.ResultsAll plankton groups show remarkably similar trends in the rates and spatio‐temporal dynamics of local biodiversity change and a pronounced non‐linearity with climate change in the current warm period. Assemblages of planktonic foraminifera and dinoflagellates started to change significantly with the onset of global warming around 15,500 to 17,000 years ago and continued to change at the same rate during the current warm period until at least 5000 years ago, while coccolithophore assemblages changed at a constant rate throughout the past 24,000 years, seemingly irrespective of the prevailing temperature change.Main conclusionsClimate change during the transition from the LGM to the current warm period led to a long‐lasting reshuffling of zoo‐ and phytoplankton assemblages, likely associated with the emergence of new ecological interactions and possibly a shift in the dominant drivers of plankton assemblage change from more abiotic‐dominated causes during the last deglaciation to more biotic‐dominated causes with the onset of the Holocene.

Comparing DNA isolation and sequencing strategies for 16S rRNA gene amplicon analysis in biofilm containing environments

Bacteria are primarily responsible for biological water treatment processes in constructed wetland systems. Gravel in constructed wetlands serves as an essential substrate onto which complex bacterial biofilms may successfully grow and evolve. To fully understand the bacterial community in these systems it is crucial to properly isolate biofilms and process DNA from such substrates. This study looked at how best to isolate bacterial biofilms from gravel substrates in terms of bacterial richness. It considered factors including the duration of agitation during extraction, extraction temperature, and enzyme usage. Further, the 16S taxonomy data subsequently produced from Illumina MiSeq reads (using the SILVA 132 ribosomal RNA (rRNA) database on the DADA2 pipeline) were compared with the 16S data produced from Oxford Nanopore Technologies (ONT) MinION reads (using the NCBI 16S database on the EPI2ME pipeline). Finally, performance was tested by comparing the taxonomy data generated from the Illumina MiSeq and ONT MinION reads using the same (SILVA 132) database. We found no significant differences in the effective number of species observed when using different bacterial biofilm detachment techniques. However, enzyme treatment enhanced the total concentration of DNA. In terms of wetland community profiles, relative abundance differences within each sample type were clearer at the genus level. For genus-level taxonomic classification, MinION sequencing with the EPI2ME pipeline (NCBI database) produced bacterial abundance information that was poorly correlated with that from the Illumina MiSeq and DADA2 pipelines (SILVA132 database). When using the same database for each sequencing technology (SILVA132), the correlation between relative abundances at genus-level improved from negligible to moderate. This study provides detailed information of value to researchers working on constructed wetlands regarding efficient biofilm detachment techniques for DNA isolation and 16 s metabarcoding platforms for sequencing and data analysis.

Fewer bowl traps and more hand netting can increase effective number of bee species and reduce excessive captures.

Reports increasingly point to substantial declines in wild bee abundance and diversity, yet there is uncertainty about how best to measure these attributes in wild bee populations. Two commonly used methods are passive trapping with bee bowls or active netting of bees on flowers, but each of these has drawbacks. Comparing the outcomes of the two methods is complicated by their uncomparable units of effort. The abundance distribution of bee species is also typically highly skewed, making it difficult to accurately assess diversity when rarer species are unlikely to be caught. The effective number of species, or Hill numbers, provides a way forward by basing the response metric on the number of equally abundant species. Our goal is to compare the effective number of bee species captured between hand netting and bowl trapping in wheatgrass prairie in South Dakota and tallgrass prairie in Minnesota, USA. Species overlap between the two methods ranged from ~40% to ~60%. Emphasis placed on rare species was important, so that 95% confidence limits overlapped between the two methods for species richness but netting exceeded trapping for Shannon's and Simpson's diversities. Netting always captured more bee species with fewer bee individuals than trapping. In most cases, the number of bees captured in bowl traps indicated substantial over-sampling, with little increase in bee species detected. Correlations between bee and floral abundance, richness, and diversity differed between netted and trapped samples. We conclude that netting and trapping together produce a more complete account of species richness, but shifting sampling emphasis from trapping to netting will result in fewer bees, but more bee species captured. Due to the different relationships between bee and floral diversities that depended on sampling method, it is unwise to compare habitat associations determined by netting with those determined by trapping.

Aquaculture production and diversification: What causes what?

Aquaculture, an important source of food supply, is expected to be the main sector to satisfy growing seafood demand in the future. Being the most diversified food product in the world, aquaculture diversification can add resilience to global food security, satisfy consumer preferences, and promote price stability. Understanding the relationships between aquaculture production and diversification and their causations is crucial for developing effective strategies to support long-term sustainability and resilience of aquaculture development. This study investigates the direction of causal relationships between aquaculture production and diversification using a panel vector autoregression (PVAR) model with three decades of aquaculture production data and the Effective Number of Species (ENS) values by country. Diversification is measured in terms of within-group diversity (ENSα) and between-group diversity (ENSβ); this approach provides deeper insights into diversification strategies. The model results show that between-group diversification is more conducive to production expansion globally, especially in the Americas and Asia, and the positive effects are long lasting. Within-group diversification also induces more production in Europe and, to a lesser extent, in Asia. Therefore, policies and market incentives that promote diversification across different species groups in the Americas and Asia, and diversification within the same species group in Europe and Asia, are potential strategies to expand aquaculture production. Other findings include production leading within-group diversification in Asia and Europe, but not in the Americas and Africa. A possible explanation is that production expansion would accumulate experience, develop scope economies and emerging technologies, and build up capacities. These factors generate spillover effects that facilitate species diversification, considering that Asia and Europe have a longer history of aquaculture development compared to the Americas and Africa. However, no significant relationship is found indicating production leading between-group diversification.

Molecular Identification and Fungal Diversity Associated with Diseases in Hass Avocado Fruit Grown in Cauca, Colombia.

Hass avocado fruit diseases are one of the main marketing constraints in Colombia. To identify and reveal the diversity of fungi associated with diseases in fruits and peduncles, symptomatic samples were collected from 67 farms in the 9 main Hass avocado-producing municipalities of the department of Cauca located in southwestern Colombia. A total of 237 monosporic isolates were obtained that were subjected to DNA extraction, amplification of the ITS region, sequencing and functional diversity analysis based on Hill numbers by municipality and altitude. The results indicated that the genera Pseudocercospora, Diaporthe, Colletotrichum, Neofusiococcum, Lasiodiplodia and Pestatoliopsis were associated with fruit diseases. The genus with the highest number of effective species was Colletotrichum. The ITS region revealed 100% identity of the species Pseudocercospora norchiensis, which was the first report of this pathogen in the crop. There was a greater richness and diversity of associated species in the three municipalities, revealing that the higher the altitude was, the lower the richness and diversity of fungi associated with fruit diseases. These results will provide a better understanding of the identification and diversity of pathogenic microorganisms present in avocado production systems in this region of Colombia.

Temporal change in phytoplankton diversity and functional group composition

One of the key challenges in managing eutrophication in coastal marine ecosystems is the harmonized cross-border assessment of phytoplankton. Some general understanding of the consequences of shifting nutrient regimes can be derived from the detailed investigation of the phytoplankton community and its biodiversity. Here, we combined long-term monitoring datasets of German and Dutch coastal stations and amended these with additional information on species biomass. Across the integrated and harmonized dataset, we used multiple biodiversity descriptors to analyse temporal trends in the Wadden Sea phytoplankton. Biodiversity, measured as the number of species (S) and the effective number of species (ENS), has decreased in the Dutch stations over the last 20 years, while biomass has increased, indicating that fewer species are becoming more dominant in the system. However, biodiversity and biomass did not show substantial changes in the German stations. Although there were some differences in trends between countries, shifts in community composition and relative abundance were consistent across stations and time. We emphasise the importance of continuous and harmonized monitoring programmes and multi-metric approaches that can detect changes in the communities that are indicative of changes in the environment.

Agronomic strategies to enhance the early vigor and yield of maize. Part I: the role of seed applied biostimulant, hybrid and starter fertilization on rhizosphere bacteria profile and diversity.

The sustainable intensification of maize-based systems may reduce greenhouse-gas emissions and the excessive use of non-renewable inputs. Considering the key role that the microbiological fertility has on crop growth and resilience, it is worth of interest studying the role of cropping system on the rhizosphere bacterial communities, that affect soil health and biological soil fertility. In this work we monitored and characterized the diversity and composition of native rhizosphere bacterial communities during the early growth phases of two maize genotypes of different early vigor, using a nitrogen (N)-phosphorus (P) starter fertilization and a biostimulant seed treatment, in a growth chamber experiment, by polymerase chain reaction-denaturing gradient gel electrophoresis of partial 16S rRNA gene and amplicon sequencing. Cluster analyses showed that the biostimulant treatment affected the rhizosphere bacterial microbiota of the ordinary hybrid more than that of the early vigor, both at plant emergence and at the 5-leaf stage. Moreover, the diversity indices calculated from the community profiles, revealed significant effects of NP fertilization on richness and the estimated effective number of species (H2) in both maize genotypes, while the biostimulant had a positive effect on plant growth promoting community of the ordinary hybrid, both at the plant emergence and at the fifth leaf stage. Our data showed that maize genotype was the major factor shaping rhizosphere bacterial community composition suggesting that the root system of the two maize hybrids recruited a different microbiota. Moreover, for the first time, we identified at the species and genus level the predominant native bacteria associated with two maize hybrids differing for vigor. These results pave the way for further studies to be performed on the effects of cropping system and specific crop practices, considering also the application of biostimulants, on beneficial rhizosphere microorganisms.

Diversity of Insect Fauna Actively Engaged in the Pollination of the Leguminosae Crop Vigna unguiculata (L.) in Jaipur, Rajasthan, India

This study was conducted to find out the insect pollinators actively engaged in the pollination of Vigna unguiculata (L.), in and around Jaipur, Rajasthan, India. About 20 species of Insect pollinators, belonging form 2 orders (Hymenoptera, Diptera), 7 families (Apidae, Dolichopodidae, Megachilidae, Muscidae, Halictidae, Syrphidae, Vespidae) and 10 Tribes (Anthophorini, Apini, Chrysosomatini, Eristalini, Megachilini, Meliponini, Muscini, Nomiinae, Vespini, Xylocopini) were recorded on this crop. These have been classified as belonging to 7 families and 11 genera. The number of species in these genera are Amegilla friese (02), Apis linnaeus (03), Ceratina latreille (01), Chrysosoma guérin-méneville (01), Eristalis linnaeus (01 species), Megachile latreille (02), Musca linnaeus (01), Nomia latreille (01), Tetragonula moure (01), Vespa linnaeus (01), Xylocopa latreille (06). The values of various diversity indices like the Simpson index, Shannon index, and Simpson index of diversity (1-D) are calculated as 0.16552, 3.0861, and 0.83448, respectively, indicating a significant abundance in the research area. Margalef's index was calculated to determine the species richness, and it was found to be 2.9595. The collision-entropy is 20, 8.53, 5.99 (r= 0,1,2) and Effective Number of Species is 2.29, 2.21, 1.17 (r= 0,1,2).

A global assessment of species diversification in aquaculture

Aquaculture is a diverse food production system, and a high species diversity in aquaculture can make the global food system more resilient. Species diversification could facilitate aquaculture growth through multiple mechanisms and increase the sector's resilience and long-term sustainability. Facing increasing challenges from climate change, disease outbreaks, market fluctuations, and other disturbances, species diversification has become a widely recognized and endorsed development strategy in the policy and scientific communities for the growth and resilience of the aquaculture sector. However, many attempts to establish new species have yielded little long-term success, and the private sector often concentrates efforts on the most advantageous species for rapid growth. This paper presents a comprehensive assessment of aquaculture species diversification at the global, regional (more than 30 country groups), and national (nearly 200 countries) levels, covering the period 1950 to 2020 with a focus on 1990 to 2020. The assessment employs the concept of “effective number of species” as a measure of diversity and uses two sub-indicators to assess within-group versus between-group diversity. The indicator system reveals detailed patterns of species diversity and uncovers different driving forces of species diversification. Additionally, the study maps the status and trends of species diversity to offer a refined perspective on species diversity profiles and diversification patterns. The findings reveal that beneath high species diversity in world aquaculture lies generally low diversity at the national level; nearly half of national aquaculture has no within-group or between-group diversity. Furthermore, species diversification has been losing momentum in recent decades, and concentration has become a more prominent development pathway, with a tendency to drive aquaculture towards a low-diversity system similar to terrestrial farming. Public interventions are crucial to promote species diversification in aquaculture for the sector's resilience and long-term sustainability. It is important to not only reduce the cost of species diversification for the private sector but also to dedicate more public efforts towards increasing its benefits and viability. While diverse diversification patterns among national aquaculture indicate no one-style-fits-all species diversification pathway, a country may draw guidance from others' experiences, especially since countries with similar species diversity profiles or diversification patterns tend to cluster geographically. Evidence-based policymaking and sector management regarding species diversification entail collaborative efforts among policymakers, scientists, and the aquaculture community to expand and refine assessment frameworks, improve data availability and quality, and efficiently utilize information, knowledge, and insights generated by these assessments to inform decision making at various levels.

Population Dynamics of Intertidal Resident Species during a Reduction in Asian Shore Crab Population

Hemigrapsus sanguineus (Asian shore crab), which is native to coastal estuarine habitats along the east coast of Asia, have overtaken a wide range of the coast in the northeastern region of the United States. Intertidal population densities of Hemigrapsus sanguineus, Cancer irroratus (Atlantic rock crab), Littorina littorea (Common periwinkle), and Modiolus demissus (Atlantic Ribbed Mussel), among others, were measured at three sample sites from 8/2/22 to 11/14/22 using quadrat sampling techniques. A period of removal was enacted solely upon Sample site #1 from 9/28/22 to 11/2/22 to cause a reduction in the Asian shore crab population. During the period of removal, no statistically significant changes in Asian shore crab demographics (Carapace size/sex ratios) would be observed (p = 0.181 for carapace size changes). There would however be an 8% decrease in Asian shore crab population density within Sample site #1, comparative to a 1% increase at Sample site 2. Rock crab population density at Sample site #1 would increase by a relatively drastic 31%, whereas the Rock crab population would experience only a 7% increase at Sample site #2. The Shannon-Weiner diversity index was used to derive the effective number of species (ENS). There would be a drastic difference in change of ENS following the removal period at Sample site #1 (increase of 0.248 ENS), and the change of ENS at Sample site #2 (decrease of 0.024 ENS), suggesting the reduction in Asian Shore Crab population played a role in increased population diversity of intertidal resident species.

Assessment of on farm agrobiodiversity and its role in food sufficiency in mid hill, Nepal

A survey was conducted in the agricultural farms in Dhulikhel Municipality, mid-hill, Kavre, Nepal aiming at assessing the status of agrobiodiversity with the purpose of understanding its role in food security taking altogether 133 farming households scattered in several settlements with lowland, upland, and home garden being the general agricultural land use systems. Biodiversity index: Shannon-Wiener Index was used to assess diversity of plant. The main purpose was to assess the farm agrobiodiversity and to find out whether biodiversity level has a direct link to household food self-sufficiency. For descriptive analysis frequency, percentage, mean and standard errors were used. In the case of inferential statistics independent sample t - test and binary logistic was used to find the odd ratio of practicing home garden. The result showed that the average landholding size was 0.66 ha/household with 0.37 ha, 0.3 ha, and 0.06 ha being upland, low land, and home garden, respectively. A total of 136 plant species were documented out of which 74 were the effective number of species in the study area. Among the used plants, fodder shared 27% of the total plant diversity followed by fruit (21%), vegetable (19%), medicinal plants (8%), pulses (8%), spices (7%), oilseeds (5%) and cereals (5%). Similarly, the mean livestock unit (LSU) was 2.65. The overall Shannon-Wiener Index was 4.30 indicating high diversity of species and 87.7% of the species were evenly distributed. The Index was higher for vegetable (3.11) followed by fruits (2.9) and fodder (2.85). Higher diversity was found in fodder trees in lowlands whereas vegetable species were more diverse in upland and home garden. Similarly, the Index was 4.29 in the upland whereas it was 4.078 in the home garden followed by 3.13 in the lowland. The evenness was 0.899, 0.87, and 0.74 in upland, home garden and lowland, respectively. Higher species diversity revealed that the site was rich in agrobiodiversity. A significant positive correlation (0.22) was observed between Shannon-Wiener Index and farming years. Similarly, positive correlation (0.33) was found between an increase in the level of agrobiodiversity and food self-sufficiency. The result demonstrated that increasing crop diversity increases the household’s ability towards food sufficiency implying the need for the formulation and implementation of efficient policy to conserve the agrobiodiversity at municipality as well as national levels.