Equitability Index Research Articles

Owalla Reservoir in South-western Nigeria: Assessment of Fish Distribution, Biological Diversity, and Water Quality Index

The Water Quality Index (WQI) was used to evaluate the ecological health and status of Owalla Reservoir and the implications on fish species distribution and biological diversity of the reservoir. Water quality and fish species were collected from three sampling zones (A, B, and C) from September 2019 to August 2020 and biological diversity indices such as dominance, Shannon-Weiner, Evenness, Brillouin, Menhinick, Margalef, Equitability, and Fishers index were calculated. The mean values measured for the temperature (25.9 ± 0.48 oC), dissolved oxygen (4.14 ± 0.10 mg/L), pH (7.0 ± 0.01), and nitrate (0.68 ± 0.25 mg/L) of Owalla Reservoir were within the recommended range; while ammonia (0.13 ± 0.20 mg/L), nitrite (0.14 ± 0.21 mg/L) were high and above the recommended limits. The WQI was highest in zone A (155.97) with an overall index value of 152.73 for the reservoir. Zone A recorded the highest relative fish abundance (49.95%) and was more diversified than other sampling zones. In terms of fish biodiversity indices, zone A had the highest richness (9), number of individuals (136), Shannon (1.84), and Brillouin (1.62) index values. Zones B and C were highest in terms of Dominance (1.0), and Evenness (1.0). Zones A and C were highest in terms of Simpson (0.83); zone B was highest in terms of Menhinick (1.58), and Fisher_alpha index (3.98) while zone C was highest in terms of Margalef (2.0), and Equitability (0.99) indices. The elevated levels of WQI, ammonia, and nitrite pose a danger to fish species and watershed systems. It is important to maintain the quality of water within Owalla Reservoir by ensuring best human practices and averting inappropriate human wastes as well as sewage disposal and agricultural activities. These should be checked for the sustainability of fish species.

Earth Fauna in Different Environments in the Southern Amazon

Objective: To evaluate the soil fauna in Permanent Preservation Areas (APP) of restored and degraded watercourses, and in a preserved forest fragment, located in the municipality of Alta Floresta - MT. Theoretical framework: Forest restoration is extremely important for the reestablishment of ecosystem functions, especially in areas on the banks of water bodies. And the evaluation of this process can be carried out through soil fauna, which is considered a bioindicator of environmental quality. Methodology: The soil fauna was collected using pitfall soil traps (Provid model), installed in the three study environments along a linear transect of 70 meters, remaining in the field for 48 hours, with subsequent collection, cleaning and screening, followed by identification at order and/or family level. Soil sampling was also carried out at the points where meso- and macrofauna sampling was established, forming a composite sample from each study area. To analyze the results, the diversity, equitability, similarity and correlation indices were calculated using the PAST software. Results and conclusion: The restored APP was the one that most matched the preserved forest fragment when evaluating the environments' soil fauna, also presenting the highest levels of diversity and equitability. The soil fauna responded to the heterogeneity of the environments, since the degraded APP had less incidence of soil organisms. Implications of the research: Validates the use of soil fauna as an instrument to assess the environmental quality of environments that are in the process of ecological restoration. Originality/value: The research helps overcome the bottleneck in the effective ecological restoration of previously degraded areas, as soil fauna can be used as another parameter for evaluating the restoration process.

Microalgal in waters and sediments of Surabaya mangrove areas

Mangrove areas stored the highest carbon content in the tropics which is three times higher than the average carbon in mainland tropical forest areas. The nutrients surround may support the growth of primary producers such microalgae. The community of microalgae was observed during the high and low tide in wet season (December 2021). Five water samples were collected during high tide, while during low tide three stations was visited to obtain the sediment samples. Supporting parameters include chlorophyll a, nutrient content, ORP, DO, and pH was measured in situ. The results showed that the microalgae communities both in waters and sediments of Surabaya mangrove areas was always consisted of Chaetoceros sp., Pleurosigma sp. and Skeletonema sp. in each sample. The abundance of microalgae in waters and sediments was ranged from 32 – 7,898 and 15,200 – 17,200 cells mL-1, respectively. Based on the Simpson’s dominance index (D), waters and sediments samples were resulting a range from 0.15 – 0.19 and 0.17 – 0.23, respectively. Whereas the Shannon’s diversity index (H′) ranged from 1.94 – 2.04 for water samples and 1.99 – 2.17 for sediment samples. The equitability index (E) of both waters and sediments was range from 0.13 - 0.63 and 0.42 - 0.86, respectively. These results show that Surabaya mangrove areas is classified as an oligotrophic area.

Biological diversity of arthropods associated with two varieties of pepper (<i>Capsicum annuum</i> L., 1753) at Nkolmelen (Yaoundé, Cameroon)

Pepper is a vegetable which plays an important role in the human diet and health. Many insects attack this plant and decrease its production in the absence of appropriate phytosanitary treatment. Thus, the objective of the present study was to record the arthropods associated with the yellow and red pepper varieties. For this purpose, weekly observations were conducted during two cropping cycles on 192 plants, using a completely randomized device. As results, the fauna of the pepper was very diverse and stable (specific richness 47 and Equitability index 0.86). The yellow pepper was the most sensitive with an average of nine insect species per plant versus eight on the red pepper. These insects belonged to seven orders (Arachnida, Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera and the Orthoptera), 28 families and 47 species. The densest orders were Diptera represented by Ceratitis capitata, Silba capsicarum, followed by Hymenoptera were represented by Camponotus floridanus, Camponotus acvapimensis and Crematogaster sp. and Hemiptera represented by Aphis gossypii, Macrosiphum euphorbiae, Pseudococcus sp. The present study provided a database on arthropodofauna of the pepper plant. This is of paramount importance for the development of healthy and sustainable protection strategies among pepper producers in order to improve national production.

The birds of Cameroon: bird survey in a forest plain of the Congo basin forest (Oveng, Cameroon) confirms the great diversity of birds linked to the vegetation of the second largest biodiversity reserve in the world as well as the distribution pattern of taxa

We carried out a bird survey in the Oveng plain in the Congo Basin Forest to investigate the avifauna as well as to explore the abundance, diversity and distribution of taxa. To obtain abundance of bird species and analyze their diversity and distribution, we used the mist net method for bird sampling for five months and performed analyzes with SAS/STAT and PAST software, respectively; moreover, to compare the diversity and dominance of the Oveng plain to other plains already explored, we proceeded to a simple comparison for a small sample, placing the values in a double-entry table and analyzing them. We captured 146 individuals belonging to 22 bird families and compared to previous surveys in this region, we recorded three new species, Campethera maculosa, Buccanodon duchaillui and Alethe diademeta; the birds caught were mainly sedentary and the rest were a mixture of intra-African, seasonal and Palearctic migrants, etc. Values ​​of the diversity indices show a great avifaunistic diversity within the Oveng site; thus, the Shannon-Wiener index (H’= 3.09) expresses the high number of the species within the Oveng avifauna while the Equitability index (J’=0.83) reveals an absence of dominance of one species and therefore an equal distribution of individuals within species. The Simpson index (λ=0.92) supports abundant species representation in Oveng’s birdlife due to the presence of year-round vegetation. The distribution pattern of taxa appeared directly linked to vegetation. Comparison of the diversity and dominance of plains avifauna supports a close relationship between the presence of vegetation and a high diversity of birds and that between an absence of vegetation and a more pronounced dominance.

Influences of zonation on water fertility and structure communities of phytoplankton and benthos in Batukaras Mangrove Forest, Pangandaran District, Indonesia

Abstract. Pratiwi D, Oktavia D, Sumiarsa D, Sunardi S. 2023. Influences of zonation on water fertility and structure communities of phytoplankton and benthos in Batukaras Mangrove Forest, Pangandaran District, Indonesia. Biodiversitas 24: 4978-4988. Mangrove forests are coastal areas with several advantages, including access to natural resources that other regions do not provide. Pangandaran has mangrove forest areas, namely Batukaras mangroves, located in Batukaras Village, Pangandaran, West Java, Indonesia. This study aims to identify the primary productivity and community structure of phytoplankton and benthos as one of the natural resources in the Batukaras mangrove with different zone patterns of mangrove (seaward and landward). The purposive sampling method determined the observation stations based on the vegetation density. The obtained data of Net Primary Productivity (NPP) was analyzed with the light and dark bottle (Winkler method). In addition, the data community structure of phytoplankton and benthos was analyzed using the Shannon Wienner diversity index (H'), equitability index (E), and Simpson dominance index (D). The results show that the NPP in seaward and landward are mesotrophic with values of 105.833 mgC/m3/h and 36.463 mgC/m3/h. The abundance of phytoplankton and benthos in seaward is 560 ind/m3 and 387 ind, while landward ranges from 1140 ind/m3 and 135 ind. Planktoniella sp. and Faunus ater dominated the community structure of phytoplankton and benthos seaward, while the landward location consisted of Oscillatoria sp. and Terebralia sulcata. The community structure of phytoplankton and benthos in seaward and landward has significant differences (<0.05). The seaward and landward zone shows relatively stable and non-polluted waters.

Diet Analysis of the Amur Sleeper (Perccottus glenii) from the Danube River Drainage Channel (Serbia)

The stomach content of 277 Amur sleeper individuals has been analyzed to present its feeding habits. Fish were sampled using electrofishing from July to November 2017 in the Danube River drainage channel near Veliko Gradište (Serbia). Fish age was estimated by otoliths examination. Ingested prey organisms were identified to the lowest reliable taxonomic level. The biotic indices: vacuity index (VI), frequency of occurrence (F), abundance (Cn), index of importance (PV), Shannon`s diversity index (H`), and equitability index (Eh) were calculated. A total of 18 prey categories and 1144 individual prey were identified in the fish diet, dominantly aquatic macroinvertebrates. There were no significant difference in diet composition between sampling months as well as 0+, 1+, and 2+ age groups (both 3+ and 4+ had one individual). Only eight individuals were found with empty intestines, thus VI was low (2.9). In average, each fish had 4.1 prey items in their intestines. For whole sample, H′ was 1.84 and Eh was 0.64. Trichoptera, Ephemeroptera, and Gastropoda were the most frequent, dominant, and abundant. The greatest diversity of prey items was recorded for fish sampled in October as well as for 2+ individuals, and the lowest for fish from August and 0+ individuals.

Effect of Grazing Management on Predator Soil Mite Communities (Acari: Mesotigmata) in Some Subalpine Grasslands from the Făgăraş Mountains-Romania.

For the first time in Romania, a complex study was conducted on soil mite communities from two types of managed grasslands: ungrazed and intensively grazed. The study was accomplished in August 2018, in the Făgăraş Mountains. Within the soil mite communities (Mesostigmata), 30 species were identified, from 80 soil samples. The following population parameters were investigated: species richness, numerical abundance, dominance, Shannon index of diversity, evenness and equitability. Eight environmental variables were also measured: soil and air humidity; soil and air temperature; soil pH; resistance of soil to penetration; soil electrical conductivity; and vegetation coverage. The results revealed that species richness, Shannon index of diversity, evenness and equitability indices had higher values in ungrazed grasslands, whereas in intensively grazed areas, the numerical abundance and dominance index had significantly higher values. The species Alliphis halleri was dominant in the ungrazed grasslands. Each type of managed grassland was characterised by specific environmental conditions, which had an important influence, even at the species level.

Effect of Anthropogenic Pressure on the Biodiversity of Benthic Macroinvertebrates in Some Urban Rivers (Yaoundé)

In Cameroon, the environmental profile is increasingly marked by anarchic urbanisation, which is strongly illustrated by the discharge of waste into the aquatic environment, leading to pollution. Indeed, the tributaries of the Mfoundi and Mefou river basins have nowadays become dumping grounds and receptacles for all kinds of waste, leading to the degradation of water quality and a reduction in biodiversity. This study aims to evaluate the effect of anthropogenic pressure on the biodiversity of benthic macroinvertebrates in three rivers of the Mfoundi basin (Ebogo, Abiergue, and Ako’o). For this purpose, some physicochemical parameters were measured according to standard methods, and benthic macroinvertebrates were collected according to the multihabitat approach. To this end, the physicochemical analyses revealed that the waters of these different streams are slightly basic and poorly oxygenated, with a saturation rate of 9.725 ± 11.74% and significant organic pollution. Biologically, a total of 5793 benthic macroinvertebrates divided into three phyla, eight orders, and more than thirty families were collected, with a population dominated by the order of insects and a low level of diversity dominated by pollutant organisms such as the Chironomidae, Lumbriculidae, and Physidae, which are saprobionts and saprophilous organisms. A redundancy analysis indicated that the main groups of benthic macroinvertebrates obtained were related to the gradients of the physicochemical parameters measured. The Shannon–Weaver diversity and Piélou equitability indexes showed the low diversity of the organisms within the different courses and their low equipartition, mainly due to the saprobiont and saprophilous groups that dominate the population. The exogenous inputs due to the increase in the population of the city of Yaoundé, which dumps its waste into the waterways, have major repercussions on the quality of the water and the population that abounds in this environment, particularly the benthic macroinvertebrates, which are an important link in the monitoring of water quality.

Analysis of Avian Diversity at Chintamoni Kar Bird Sanctuary: An Urban Forest Perspective

Chintamoni Kar Bird Sanctuary (CKBS) is an urban forest located on the southern fringes of Kolkata. The objective of our study was to document and analyze the diversity of the avian population in CKBS. The line transect method was used and avian diversity, species richness and evenness were analyzed using Shannon Diversity Index, Shannon Equitability Index, relative diversity and relative abundance. Our study recorded 37 bird species belonging to 9 orders and 23 families with most species being recorded from Order Passeriformes followed by Piciformes and Ciconiiformes. The species were well distributed across a number of avian families. Birds rare in metropolises like the Oriental white eye (Zosterops palpebrosus) were also recorded here. Analysis of relative abundances showed that many species comparatively rare in cities like the common tailor bird (Orthotomus sutorius) and white throated fantail (Rhipidura albicollis) showed an abundance similar to more commonly seen species. Values of 2.844 and 0.788 were obtained for Shannon Diversity Index and Shannon Equitability Index indicating high species diversity and evenness. However, high species diversity is not due to assemblage of migratory birds in winter. Species diversity and evenness are highest during the summer months (Shannon Diversity Index = 2.862; Shannon Equitability Index = 0.812) which could be due to dense forest cover, a large number of fruit bearing trees and many water bodies in the sanctuary which provide a favourable habitat for birds in hot weather. Our study indicates that a number of birds appear to be thriving as a stable avian community at CKBS and this urban forest acts as a haven for bird species otherwise rare in Kolkata, further emphasizing the need for taking necessary conservation measures for protection for this urban forest under the strained environmental conditions prevalent in urban metropolises.

Assessment of Bees’ Diversity within Ngel-Nyaki Forest Reserve at Taraba State, Nigeria

A field survey was conducted in Ngel-Nyaki Forest Reserve to assess the diversity of bees within the Reserve. Two methods of sampling techniques were used to sample bee species, opportunistic sampling and systematic sweep netting. Opportunistic sampling method was applied by sweep netting bees along 100 m plot where flowering plants were blooming. Collection was conducted by a single collector using an active search by walking randomly around the plot observing flowering plants and searching for bees foraging on the flowers then a sweep net was used for capturing bees. Sweep netting was conducted, line transect established within the plots for two hours, from 6:00am to 11:00am spending 20 minutes in each plot considering when the weather is conducive for bees’ activity. This was done using entomological sweep net. Bees captured were killed in a killing bottle containing 70% ethanol. Specimens were pinned on a board and unique codes were assigned to each species before identification. Bees were identified to species level by using published systematic keys, Bees field guide and use of online materials. All data were computed using Microsoft® Excel® 2016 and percentage abundance composition of bees were calculated.575 bees spreading across 3 families and 12 species were sampled. The most abundant species was the honey bee (Apismellifera) (245; 42.53%),followed by memic bee (Megachile sp.)(89;15.45%),and the least was leafcutter bee(Osmiasp.) (2;0.35%). In terms of diversity by species, Shannon Diversity Index (H) and Shannon Equitability Index (EH) were 1.694893 and 0.736083respectively while diversity by plots using Shannon Diversity Index (H) and Shannon Equitability Index (EH) were 1.750688 and 0.977078 respectively. This study therefore, brings to the fore the diversity of bees within Ngel-Nyaki Forest Reserve and underline the need for sustainable actions to be taken to conserve beneficial rare species while managing the abundant ones.

Tropical savanna conversion to exotic pastures negatively affects taxonomic and functional diversity of dung beetle assemblages, but not dung removal

Abstract1. The replacement of natural systems with agricultural lands is the main factor resulting in land use change in tropical regions. Tropical savannas cover more than 20% of the global land surface, and one‐fifth of the world's population depends directly on these systems.2. Here, we aim to understand how the conversion of tropical savanna into exotic pastures affects the taxonomic and functional metrics of communities and dung removal, using dung beetles as a focal group in a biodiversity hotspot—the Brazilian Cerrado biome. We used species richness, abundance, total biomass, and species composition as assemblage metrics, and functional richness, equitability and dispersion indices, and functional composition as functional diversity metrics.3. The replacement of native savanna with exotic pastures negatively affected taxonomic and functional metrics, suggesting a simplified system where some disturbance‐tolerant species become dominant. However, the relationship between dung removal and functional richness was higher in pastures compared to savanna.4. Our results demonstrated that responses of dung beetle assemblages and dung removal to land use changes are decoupled, idiosyncratic and context‐dependent, presenting challenges for making predictions and generalisations about the effects of land use change on ecological processes mediated by animals.

Diversity and Abundance of Mosquitoes in the Seaport Area of San Pedro (Côte d’Ivoire)

Introduction: As part of the implementation of arbovirus vector surveillance at the Seaport of San Pedro by the International Health Regulations, entomological surveys were conducted from March to July 2018 to determine the diversity and abundance of putative arbovirus vectors. Method: Mosquitoes were collected as immatures and adult stages in the activity and residential areas of the San Pédro Seaport platform. Results:A total of 7 and 14 species of mosquitoes were collected in the activity and residential areas respectively, with a dominance of the genera Culex species (5 in the activity area and 10 in the residential area). Only Aedes aegypti had a high frequency of occurrence with 47.29% in the activity area and 61.97% in the residential area. This species was accessory in activity areas and regular in residential areas. The diversities indices were higher in the residential area with 1.27, 0.64, and 0.48 respectively for Shannon’s Index, Simpson’s Index, and Equitability Index. Aedes aegypti accounted for 78.42% of the mosquitos collected in activity area and 49.47% of those collected in the residential area with an exophilic respective of 88.32% and 75.21%. Conclusion: Aedes aegypti abundance at the Seaport of San Pedro constitutes a permanent health threat that requires appropriate control and surveillance actions.

Assessing plant diversity change in logged and unlogged dense semi-deciduous production forest of eastern Cameroon

This study was carried out in the dense semi-deciduous production forest of East Cameroon. The objective of this work of this study was to provide comparative floristic knowledge that can serve as a basis for the planning and sustainable management of ligneous plant resources in Communal Forests before and after logging. Sampling was done in unlogged and logged forest. Data collection was carried out using the linear transects subdivided into 10 plots of 25 m × 20 m (500 m2) with an equidistance of 225 m for the inventory of all trees with dbh ≥10 cm installed measured at 1.3 m above ground level. Nested quadrats 5 m × 5 m, oriented south-west and north-east were set up in each plot for the counting and identification of all individuals with a diameter less than 10 cm. The analysis of inventory data showed that the floristic composition was higher in the unlogged forest. The individuals were more evenly distributed in the logged (Pielou's equitability index = 0.83) than in the unlogged forest. The study of the functional spectra showed that the flora of the two forest types was dominated by Guinean-Congolese species (67.57% in the unlogged forest and 63.07% in the logged forest) and Phanerophytes, particularly Mesophanerophytes. The dominance of sarcochorous species reveals that the main mode of dissemination in this forest is zoochory, particularly endozoochory. The presence of pleochroic species in the logged forest reveals the importance of dissemination by water in the environment. The plants surveyed were divided into five plant assemblages (three for logged forest and two for unlogged forest) based on ecological parameters. The findings of this study suggest that forest management which combines assisted natural regeneration with the natural process of secondary succession facilitates the reconstitution of the vegetation cover and, by extension, the conservation of biodiversity in post-logging forest concessions.

Diversity, Composition and Abundance of Avian Species of Oxbow Lake and Surrounding Area in Purbasthali, West Bengal, India

Purbasthali oxbow lake is an important habitat for thousands of migratory and resident avian species. This study aimed to determine the current status of avifaunal diversity of Purbasthali oxbow lake and its surrounding area. During this study, diversity, composition and abundance, feeding guilds and the relationship between their habitat preferences and the numbers of individuals were determined. Direct observation, line transects and point count methods were applied for bird surveys for three consecutive years from 2019 to 2022. A total of 145 species of birds were documented, belonging to 19 orders and 49 families. Among the total species, 57 are migratory in nature and 47 are showing declining global trend. Quantitative diversity estimation were performed during the study are the Shannon-Weiner index, Simpson's Diversity Index, Shannon equitability index and relative diversity. Density and diversity of avian species was highest during post-monsoon and lowest in pre monsoon. This indicates the winter assemblages of many migratory birds choose this lake as their feeding and resting grounds.

Komposisi Dan Struktur Komunitas Fitoplankton Di Perairan Teluk Sungai Pisang Kota Padang Sumatera Barat pada Musim Kemarau

AbstractSungai Pisang Bay is located south of Padang City, at this location there are various activities including Pasumpahan Island water tourism, fishing, and settlement activities. This is expected to pollute the sea and have an impact on marine biota, especially phytoplankton. The purpose of this study was to examine the quality of seawater based on the composition and structure of the phytoplankton community in the Sungai Pisang Bay, Padang City. The research was conducted using survey methods and field sampling using plankton net at three sample stations on Pasumpahan Island, Ujung and Setan Island. The result is conducted 100 species of phytoplankton were found consisting of 4 classes, namely Bacillariphyceae 66 species, Chlorophycaeae 1 species, Cyanophyceae 3 species and Dinophyceae 30 species. The phytoplankton diversity index in April ranged from 2.056-3.165 and in Mei 2.644-2.977. The phytoplankton equitability index in April ranged from 0.565-0.836 and in Mei 0.727-0.809. The phytoplankton dominance index in April ranged from 0.054-0.087 and in Mei 0.096-0.131. Physical Chemistry in good condition base on KEPMEN LH No 51/2004. It can be concluded that the condition of Sungai Pisang Bay waters is based on the presence of phytoplankton in dry conditions is good.

Assessment of grouper’s catch, diversity and abundance in Saleh Bay, West Nusa Tenggara, Indonesia

Grouper are demersal fishes that can be found in tropical and subtropical waters. In Indonesia, one of the areas where grouper production takes place in Saleh Bay, a semi-enclosed water with small islands, coral reefs and a high diversity. Information’s about the population and abundance of grouper species in Saleh Bay are currently limited. The benefits of this research are to enhance the availability of information on grouper diversity and the area as grouper fishing ground for future improvement on grouper fisheries management in Saleh Bay. Therefore, the study aimed to analyse the diversity, equitability, species richness and dominance index of different grouper species and the grouper fishing ground in this area. The data were obtained from field observations and fish landing data. Grouper caught have been calculated for each fishing gear based on the following parameters: diversity index (Shannon-Wiener), species richness, equitability, and dominance index. The results showed that grouper fishing grounds are spread over Saleh Bay. Fishers caught grouper around small islands with coral reefs. The diversity of grouper for each fishing gear ranged in a moderate category. We found that the bottom longline caught the highest species richness of grouper compare to other fishing gears. The dominance index showed no dominance using each examined fishing gear, or it can be said that grouper species are evenly caught with each fishing gear based on the calculation of the equitability index.

Insect Diversity in the Coastal Pinewood and Marsh at Schinias, Marathon, Greece: Impact of Management Decisions on a Degraded Biotope

The insects trapped in 63 plots positioned in a mixed pinewood and a marsh in Schinias, Marathon, Greece is studied relative to the anthropogenic disturbance. The last anthropogenic impact was recently intensified because of the Olympic Games in the area. One hundred and forty insect species were found that had abundances greater than two individuals in each sampling session in all plots. Seven insect community types were found using cluster analysis. The types, which corresponded to recognized habitats, re-emerged in a non-metric multidimensional scaling ordination. It was also found that insects tended to dwell in different plots, even in the same habitat. The invading P. halepensis Mill., which replaces P. pinea L., changed the entomofauna. The seven habitats had different numbers of bioindicators out of 74 insect species, not in general correlated with human impact. Three components of insect diversity were measured, and the temporal species turnover was consistently higher than the spatial one. In this sense, pine habitats were rated first in terms of overall insect diversity. In terms of biodiversity, the impact on the various biotopes was assessed utilizing the diversity–equitability index V, which indicated that the two P. halepensis-dominated habitats have negative V values together with the habitat dominated by Tamarix hampeana Nied. The conservation of P. pinea and the marsh habitats is recommended for conserving local entomofauna and stopping the progression of P. halepensis. The optimization of management strategies to meet the management goals of all elements of this degraded ecosystem seems to be crucial.

Growth of water hyacinth biomass and its impact on the floristic composition of aquatic plants in a wetland ecosystem of the Brahmaputra floodplain of Assam, India.

Inland water plants, particularly those that thrive in shallow environments, are vital to the health of aquatic ecosystems. Water hyacinth is a typical example of inland species, an invasive aquatic plant that can drastically alter the natural plant community's floral diversity. The present study aims to assess the impact of water hyacinth biomass on the floristic characteristics of aquatic plants in the Merbil wetland of the Brahmaputra floodplain, NE, India. Using a systematic sampling technique, data were collected from the field at regular intervals for one year (2021) to estimate monthly water hyacinth biomass. The total estimate of the wetland's biomass was made using the Kriging interpolation technique. The Shannon-Wiener diversity index (H'), Simpson's diversity index (D), dominance and evenness or equitability index (E), density, and frequency were used to estimate the floristic characteristics of aquatic plants in the wetland. The result shows that the highest biomass was recorded in September (408.1 tons/ha), while the lowest was recorded in March (38 tons/ha). The floristic composition of aquatic plants was significantly influenced by water hyacinth biomass. A total of forty-one plant species from 23 different families were found in this tiny freshwater marsh during the floristic survey. Out of the total, 25 species were emergent, 11 were floating leaves, and the remaining five were free-floating habitats. Eichhornia crassipes was the wetland's most dominant plant. A negative correlation was observed between water hyacinth biomass and the Shannon (H) index, Simpson diversity index, and evenness. We observed that water hyacinths had changed the plant community structure of freshwater habitats in the study area. Water hyacinth's rapid expansion blocked out sunlight, reducing the ecosystem's productivity and ultimately leading to species loss. The study will help devise plans for the sustainable management of natural resources and provide helpful guidance for maintaining the short- to the medium-term ecological balance in similar wetlands.

Diversity of duckweed (<i>Lemnaceae</i>) associated yeasts and their plant growth promoting characteristics

<abstract> <p>The diversity of duckweed (<italic>Lemnaceae</italic>) associated yeasts was studied using a culture-dependent method. A total of 252 yeast strains were isolated from 53 duckweed samples out of the 72 samples collected from 16 provinces in Thailand. Yeast identification was conducted based on the D1/D2 region of the large subunit (LSU) rRNA gene sequence analysis. It revealed that 55.2% and 44.8% yeast species were Ascomycota and Basidiomycota duckweed associated yeasts, respectively. Among all, <italic>Papiliotrema laurentii</italic>, a basidiomycetous yeast, was found as the most prevalent species showing a relative of frequency and frequency of occurrence of 21.8% and 25%, respectively. In this study, high diversity index values were shown, indicated by the Shannon-Wiener index (<italic>H′</italic>), Shannon equitability index (<italic>E<sub>H</sub></italic>) and Simpson diversity index (<italic>1-D</italic>) values of 3.48, 0.86 and 0.96, respectively. The present results revealed that the yeast community on duckweed had increased species diversity, with evenness among species. Principal coordinate analysis (PCoA) revealed no marked differences in yeast communities among duckweed genera. The species accumulation curve showed that the observed species richness was lower than expected. Investigation of the plant growth promoting traits of the isolated yeast on duckweed revealed that 178 yeast strains produced indole-3-acetic acid (IAA) at levels ranging from 0.08–688.93 mg/L. Moreover, siderophore production and phosphate solubilization were also studied. One hundred and seventy-three yeast strains produced siderophores and exhibited siderophores that showed 0.94–2.55 activity units (AU). One hundred six yeast strains showed phosphate solubilization activity, expressed as solubilization efficiency (SE) units, in the range of 0.32–2.13 SE. This work indicates that duckweed associated yeast is a potential microbial resource that can be used for plant growth promotion.</p> </abstract>