scholarly journals Zooplankton species composition and diversity in the seagrass habitat of Lawas, Sarawak, Malaysia

2021 ◽  
Vol 9 ◽  
Author(s):  
Johan Ismail ◽  
Abu Hena Mustafa Kamal ◽  
Mohd Hanafi Idris ◽  
S. M. Nurul Amin ◽  
Hadi Hamli ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Abiotic Factors ◽  
Species Abundance ◽  
Seagrass Habitat ◽  
Zooplankton Species ◽  
Analysis Model ◽  
Marine Fauna ◽  
Important Species ◽  
Parvocalanus Crassirostris ◽  
Chemical Conditions

Seagrass habitats are considered to be some of the most biodiverse ecosystems on the planet and safeguard some ecologically and economically important fauna, amongst which are some globally threatened species, including dugong. Malaysian seagrass ecosystems are not widespread, but their existence supports some significant marine fauna. A rigorous zooplankton study was conducted from May 2016 to February 2017, in the seagrass habitat of Lawas, Sarawak, Malaysia, to examine their temporal composition and diversity, together with their ecological influences. A total of 45 zooplankton species from 13 significant groups were recorded in the seagrass habitat. The population density of zooplankton ranged between 2,482 ind/m³ and 22,670 ind/m³ over three different seasons. A single zooplankton copepod was found to be dominant (47.40%), while bivalves were the second largest (31.8%) group in terms of total abundance. It was also noticed that the average relative abundance (0.62) and important species index (62.08) of copepods were higher than for other groups that exist in the seagrass meadow, whereas copepod Parvocalanus crassirostris showed both the highest average relative abundance (0.41) and the highest important species index (41.15). The diversity (H') and richness index of the intermediate season were found to be highest due to favourable physico-chemical conditions. Within the referred seasonal cluster, the wet and dry seasons were almost similar in terms of species abundance, while the intermediate season was distinct, with high species diversity backed by ANOSIM analysis results. Copepod and bivalves formed one group with a common similarity level of 0.80. The CCA (Canonical Correspondence Analysis) model established that abiotic factors, especially turbidity, NO2, rainfall, dissolved oxygen and pH were significantly correlated with abundance of individual groups of zooplankton. Zooplankton assemblage and abundance in Lawas were found to be very rich in multiple seasons, indicating that the productivity of uninterrupted seagrass habitat might be high and the system rich in biodiversity.

scholarly journals Exploring the Functional Strategies Adopted by Coastal Plants Along an Ecological Gradient Using Morpho-functional Traits

2021 ◽  
Author(s):  
Daniela Ciccarelli ◽  
Cleusa Bona
Keyword(s):  
C4 Photosynthesis ◽  
Abiotic Factors ◽  
Species Abundance ◽  
Organic Matter Content ◽  
Matter Content ◽  
Strong Interactions ◽  
Soil Parameters ◽  
Dry Matter Content ◽  
Ecological Gradient ◽  
Ecological Conditions

AbstractCoastal dunes are characterised by strong interactions between biotic and abiotic factors along a short gradient from the shoreline to the inland region. We carried out an ecological analysis of the vegetation in a protected area of the Italian coast to evaluate the relationships among species abundance, the occurrence of morphoanatomical traits related to leaves, stems, and roots, and soil variables. Three transects were established perpendicular to the shoreline, with 27 plots distributed in the frontal dunes, backdunes, and temporarily wet dune slacks. An analysis based on community-weighted mean values showed that the pioneer communities of the frontal dunes were dominated by ruderals that are well adapted to the harsh ecological conditions of these environments, showing succulent leaves, high limb thickness values, and low values for leaf dry matter content (LDMC). The backdune vegetation was a mosaic of annual herbaceous and perennial shrub communities showing both ruderal and stress-tolerant strategies (clonality, sclerified leaves, high LDMC values, root phenolics) consistent with less extreme ecological conditions. The dune slack areas were dominated by plants showing adaptations to both arid and flooded environments, such as C4 photosynthesis, amphistomatic leaves, and abundant aerenchyma in the roots. The invasive status, C4 photosynthesis, leaf trichomes, and aerenchyma in the roots were significantly correlated with soil humidity, organic matter content, and pH. These results demonstrate the usefulness of anatomical traits (including root system traits) in understanding the functional strategies adopted by plants. Invasive species tended to occupy plots with high levels of soil moisture, suggesting an avoidance strategy for the harsh environmental conditions of coastal sand dunes. Finally, we suggest including information regarding root systems into coastal monitoring programs because they are directly linked to soil parameters useful in coastal dune management and protection.

scholarly journals Nutrient supply controls the linkage between species abundance and ecological interactions in marine bacterial communities

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Tianjiao Dai ◽  
Donghui Wen ◽  
Colin T. Bates ◽  
Linwei Wu ◽  
Xue Guo ◽  
...  
Keyword(s):  
Nutrient Availability ◽  
Copy Number ◽  
Abiotic Factors ◽  
Species Abundance ◽  
Coastal Sediment ◽  
Global Ocean ◽  
Bacterial Growth Rate ◽  
Opposite Pattern ◽  
Microbial Species ◽  
Rare Biosphere

AbstractNutrient scarcity is pervasive for natural microbial communities, affecting species reproduction and co-existence. However, it remains unclear whether there are general rules of how microbial species abundances are shaped by biotic and abiotic factors. Here we show that the ribosomal RNA gene operon (rrn) copy number, a genomic trait related to bacterial growth rate and nutrient demand, decreases from the abundant to the rare biosphere in the nutrient-rich coastal sediment but exhibits the opposite pattern in the nutrient-scarce pelagic zone of the global ocean. Both patterns are underlain by positive correlations between community-level rrn copy number and nutrients. Furthermore, inter-species co-exclusion inferred by negative network associations is observed more in coastal sediment than in ocean water samples. Nutrient manipulation experiments yield effects of nutrient availability on rrn copy numbers and network associations that are consistent with our field observations. Based on these results, we propose a “hunger games” hypothesis to define microbial species abundance rules using the rrn copy number, ecological interaction, and nutrient availability.

scholarly journals Estimation of the relative abundance of species in artificial mixtures of insects using low-coverage shotgun metagenomics

2020 ◽  
Vol 4 ◽  
Author(s):  
Lidia Garrido-Sanz ◽  
Miquel Àngel Senar ◽  
Josep Piñol
Keyword(s):  
Relative Abundance ◽  
Species Abundance ◽  
Single Species ◽  
Insect Species ◽  
Individual Species ◽  
Advanced Degree ◽  
Mixed Species ◽  
Species List ◽  
Shotgun Metagenomics ◽  
Low Coverage

Amplicon metabarcoding is an established technique to analyse the taxonomic composition of communities of organisms using high-throughput DNA sequencing, but there are doubts about its ability to quantify the relative proportions of the species, as opposed to the species list. Here, we bypass the enrichment step and avoid the PCR-bias, by directly sequencing the extracted DNA using shotgun metagenomics. This approach is common practice in prokaryotes, but not in eukaryotes, because of the low number of sequenced genomes of eukaryotic species. We tested the metagenomics approach using insect species whose genome is already sequenced and assembled to an advanced degree. We shotgun-sequenced, at low-coverage, 18 species of insects in 22 single-species and 6 mixed-species libraries and mapped the reads against 110 reference genomes of insects. We used the single-species libraries to calibrate the process of assignation of reads to species and the libraries created from species mixtures to evaluate the ability of the method to quantify the relative species abundance. Our results showed that the shotgun metagenomic method is easily able to set apart closely-related insect species, like four species of Drosophila included in the artificial libraries. However, to avoid the counting of rare misclassified reads in samples, it was necessary to use a rather stringent detection limit of 0.001, so species with a lower relative abundance are ignored. We also identified that approximately half the raw reads were informative for taxonomic purposes. Finally, using the mixed-species libraries, we showed that it was feasible to quantify with confidence the relative abundance of individual species in the mixtures.

Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives

2018 ◽  
Keyword(s):  
Fisheries Management ◽  
Species Abundance ◽  
Artificial Reef ◽  
Coastal Development ◽  
Coastal Resource Management ◽  
Important Species ◽  
Management Objectives ◽  
Coastal Resource ◽  
Before And After ◽  
Habitat Enhancement

<em>Abstract</em>.—Multiple coastal development activities coupled with unsustainable management have caused environmental degradation in the Santa Marta region of Colombia. To mitigate this impact, Ecopetrol entered into alliances with private and government institutions to initiate an integrative artificial reef project in Pozos Colorados Bay. To develop the project’s framework, it was necessary to (1) establish context and objectives, (2) design plans and reef construction, (3) strengthen a target social population, and (4) conduct pre- and postdeployment ecological assessments. The achievement of each objective was met with delays and constraints, mainly due to administrative issues and legal requirements. Nevertheless, interventions and interactions among representatives of the 10 institutions involved in the project, as well as the strong commitment of fishers from three organizations in all stages of the process, were indicators of project’s success. Together, these actions and contributions resulted in the deployment of the first six artificial reefs in a 137-ha area. Moreover, recorded changes in biological assemblages before and after reef deployment (richness: 3–37 species; abundance: 30.3–1,615.7 individuals), along with the presence of commercial, ecological, and endangered important species, support the concept of habitat enhancement procedures used here as a strategy for biodiversity conservation with potential for ecotourism activities. The utilization of this technology should be conducted in compliance with concerted schemes for coastal resource management and precautionary principles, directed towards the conformation of discrete marine reserves as future models of sustainable production in sensitive areas.

scholarly journals Influence of crop species and edaphic factors on the distribution and abundance of trichoderma in alfisol soils of southern India

2014 ◽  
Vol 73 (1) ◽  
pp. 37-50 ◽  
Author(s):  
Vellaisamy Muniappan ◽  
Thangavelu Muthukumar
Keyword(s):  
Relative Abundance ◽  
Abiotic Factors ◽  
Morphological Characteristics ◽  
Significant Negative Correlation ◽  
Edaphic Factors ◽  
Crop Species ◽  
Trichoderma Species ◽  
Soil P ◽  
Fungal Abundance ◽  
Dry Soil

Abstract The effect of crop species and edaphic factors on the distribution of Trichoderma species in Alfisol soil under different agrosystems was evaluated. Each soil sample was assayed for nine abiotic factors and culturable microfungal populations. Fungal abundance was determined by dilution plate technique, and the identification of fungi was based on morphological characteristics. Pearson’s correlation coefficient was used to determine the relationship of association between these factors and the presence and abundance of Trichoderma species in each soil type. The abundance of soil fungi ranged between 7.0 × 103 and 13.6 × 103 colony forming units (cfus) per gram of dry soil. The population densities of the two Trichoderma species (T. koningii and T. viride) isolated in the present study varied significantly with crop species and their abundance (varied from 0.6 to 3.6 × 103 cfus g-1 dry soil). Twenty-two other colony-forming fungal types with an abundance ranging between 7.0 × 103 and 13.6 × 103 cfus g-1 dry soil were also isolated in the present study. As soil pH negatively influenced relative abundance of T. koningii, soil P and relative abundance of T. viride were significantly and positively correlated to each other. Further, relative abundance of T. koningii was significantly and positively correlated to relative abundance of Aspergillus fumigatus but negatively correlated to relative abundance of Stachybotrys atra. Likewise, a significant negative correlation existed between relative abundance of T. viride and Absidia glauca.

scholarly journals Physico-chemical conditions at Watlab ghat in Wular lake, Kashmir

2013 ◽  
Vol 14 (3) ◽  
pp. 1-7
Author(s):  
Saltanat Parveen ◽  
Altaf H. Ganai
Keyword(s):  
Water Temperature ◽  
Negative Correlation ◽  
Lake Water ◽  
Abiotic Factors ◽  
Significant Negative Correlation ◽  
Specific Conductance ◽  
Water Type ◽  
Physico Chemical ◽  
Wular Lake ◽  
Chemical Conditions

The present limnological investigations include analysis of various physico- chemical parameters at the selected site in Wular lake, Kashmir (a Ramsar site) from March, 2007 to February, 2008. The aim of current study was to evaluate the status of the Wular lake water on the basis of different physico-chemical conditions. The water depth ranged from 1.35 (m) to 2.60 (m). The pH of the water was on alkaline side throughout the study period. The lake depicted the usual cation progression: Ca > Mg. The lake can be categorized as calcium rich after Ohle (1934). Specific conductance was found low in spring and summer. High values of transparency were recorded in winter. The lake water is typical hard water type. The alkalinity was due to bicarbonates only. High values of both NO3–N (338 ?g/L) and PO4–P (203 ?g/L) were recorded during summer. Statistical analysis was also carried out to find out the degree of relationship between various abiotic factors. Dissolved oxygen showed significant negative correlation with water temperature (r = –0.839), whereas significant positive correlation with pH (r = 0.854) at the selected site. pH showed significant negative correlation with water temperature (r = –0.777) and CO2 (r = –0.854) respectively, at the selected site.

scholarly journals Plant dominance in a subalpine montane meadow: biotic vs. abiotic controls of subordinate diversity within and across sites

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5619 ◽  
Author(s):  
Erika LaPlante ◽  
Lara Souza
Keyword(s):  
Species Diversity ◽  
Observational Study ◽  
Plant Species ◽  
Functional Traits ◽  
Relative Abundance ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Removal Experiment ◽  
Plant Removal ◽  
Montane Meadow

Background Understanding the underlying factors that determine the relative abundance of plant species is critical to predict both biodiversity and ecosystem function. Biotic and abiotic factors can shape the distribution and the relative abundance of species across natural communities, greatly influencing local biodiversity. Methods Using a combination of an observational study and a five-year plant removal experiment we: (1) documented how plant diversity and composition of montane meadow assemblages vary along a plant dominance gradient using an observational study; (2) tracked above- and belowground functional traits of co-dominant plant species Potentilla and Festuca along a plant dominance gradient in an observational study; (3) determined whether plant species diversity and composition was directly influenced by commonly occurring species Potentilla and Festuca with the use of a randomized plot design, 5-year plant removal experiment (no removal control, Potentilla removed, Festuca removed, n = 10). Results We found that subordinate species diversity and compositional dissimilarity were greatest in Potentilla and Festuca co-dominated sites, where neither Potentilla nor Festuca dominated, rather than at sites where either species became dominant. Further, while above- and belowground plant functional traits varied along a dominance gradient, they did so in a way that inconsistently predicted plant species relative abundance. Also, neither variation in plant functional traits of Festuca and Potentilla nor variation in resources and conditions (such as soil nitrogen and temperature) explained our subordinate diversity patterns. Finally, neither Potentilla nor Festuca influenced subordinate diversity or composition when we directly tested for their impacts in a plant removal experiment. Discussion Taken together, patterns of subordinate diversity and composition were likely driven by abiotic factors rather than biotic interactions. As a result, the role of abiotic factors influencing local-level species interactions can be just as important as biotic interactions themselves in structuring plant communities.

scholarly journals Species composition and diversity of freshwater snails and land snails at the swampy areas and streams edges in the urban zone of Douala, Cameroon

2021 ◽  
Vol 15 (4) ◽  
pp. 1297-1324
Author(s):  
Edith Laure Kenne ◽  
Jeanne Agrippine Yetchom-Fondjo ◽  
Mohamed Basile Moumite ◽  
Sedrick Junior Tsekane ◽  
Babell Ngamaleu-Siewe ◽  
...  
Keyword(s):  
Species Abundance ◽  
Positive Association ◽  
Urban Environments ◽  
Land Snails ◽  
School Age Children ◽  
Freshwater Snails ◽  
Intermediate Hosts ◽  
Important Species ◽  
Infected People ◽  
The City

Fascioliasis and bilharzia occur in the Littoral region of Cameroon. Recent reports indicate a high prevalence of bilharzia in school-age children in the locality of Njombé-Penja, close to the city of Douala. This infectious disease may spread in the near future to the city of Douala, especially if the localities at risk are visited by infected people, who defecate or urinate in streams or swamps as is the habit of populations in populous zones of the city and where environmental cleanliness is not respected. It is known that several molluscs are intermediate hosts of the infectious agents of this pathology but little is known about the snail’s community structure at the coastal zone of the country. The present study aimed to establish a baseline of information on the distribution of snails in the urban environments of the Douala coastal Littoral-zone, as a first step in evaluating the status and the occurrence level of snails known as intermediate hosts of schistosomiasis and distomatosis agents. Seventy-three sample units where inspected from July to November 2020 in eight quarters of the Douala city, using 49 non-contiguous transects 5x40 m² each along streams and 24 non-contiguous quadrates 10x10 m² each around swamps. A total of 4,068 snail’s shelter belonged to 9 families: 3(33.3%) and 6 (66.7%) families for land and freshwater snails respectively. Specimens belonged to 14 genera [6 (42.9%) and 8 (57.1%) genera for land and freshwater snails respectively], and 30 species [14 (46.7%) and 16 (53.3%) species for land and freshwater snails respectively]. Land snails were most diverse [E(Sn=151) = 14 ± 0 species] than freshwater snails [E(Sn=151) = 11 ± 1 species]. Economically important species were highly represented in land snails (30.3%) and lowly represented in freshwater snails (6.1%). Between land snails Achatina and Archachatina (invasive pests for agriculture) were highly recorded in Bépanda-Sic-Cacao, Makepé-Missoké and PK10-Plateau quarters while between freshwater snails known as obligate intermediate hosts for fascioliasis and bilharzia agents, Lymnaea was recorded in Bépanda-Sic-Cacao, Nkomba and Mbanga-Pongo quarters while Biomphalaria occurred exclusively in PK10-Plateau quarter. The community exhibited low evenness, low species richness, low species diversity and low dominance by a few species. The theoretical lognormal model fitted the species abundance distributions and species exhibited a positive association (Schluter’s ratio VR = 6.69, statistic W = 53.49, df = 8, p<0.001 for land snails; VR = 2.27, W = 18.18, df = 8, p = 0.020 for freshwater snails; VR = 4.17, W = 33.42, p<0.001 for the pooled data). Low dominance by a few species indicated that study sites were slightly influenced by interspecific competition and/or disturbance by human activities.

scholarly journals Dominance across montane meadows: Patterns and processes structuring plant communities

2018 ◽  
Author(s):  
Erika LaPlante ◽  
Lara Souza
Keyword(s):  
Species Diversity ◽  
Observational Study ◽  
Plant Species ◽  
Functional Traits ◽  
Plant Communities ◽  
Relative Abundance ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Removal Experiment ◽  
Plant Removal

Background. Understanding the underlying factors that determine the relative abundance of plant species is critical to predict both biodiversity and ecosystem function. Biotic and abiotic factors can shape the distribution and the relative abundance of species across natural communities, greatly influencing local biodiversity. Methods. Using a combination of an observational study and a five-year plant removal experiment we: (1) documented how plant diversity and composition of montane meadow assemblages vary along a plant dominance gradient using an observational study; (2) tracked above- and belowground functional traits of co-dominant plant species Potentilla and Festuca along a plant dominance gradient in an observational study; (3) determined whether plant species diversity and composition was directly influenced by commonly occurring species Potentilla and Festuca with the use of a randomized plot design, 5-year plant removal experiment (no removal control, Potentilla removed, Festuca removed, n=10) . Results. We found that subordinate species diversity and compositional dissimilarity were greatest in Potentilla and Festuca co-dominated sites, where neither Potentilla nor Festuca dominated, rather than at sites where either species became dominant. Further, while above- and belowground plant functional traits varied along a dominance gradient, they did so in a way that inconsistently predicted plant species relative abundance. Also, neither variation in plant functional traits of Festuca and Potentilla nor variation in resources and conditions (such as soil nitrogen and temperature) explained our subordinate diversity patterns. Finally, neither Potentilla nor Festuca influenced subordinate diversity or composition when we directly tested for their impacts in a plant removal experiment. Discussion. Taken together, patterns of subordinate diversity and composition were likely driven by abiotic factors rather than biotic interactions. As a result, the role of abiotic factors influencing local-level species interactions can be just as important as biotic interactions themselves in structuring plant communities.

scholarly journals The leaf bacterial microbiota of female and male kiwifruit plants in distinct seasons: assessing the impact of Pseudomonas syringae pv. actinidiae

2021 ◽  
Author(s):  
Aitana Ares ◽  
Joana Pereira ◽  
Eva Garcia ◽  
Joana Costa ◽  
Igor Tiago
Keyword(s):  
Bacterial Community ◽  
Pseudomonas Syringae ◽  
Relative Abundance ◽  
Bacterial Communities ◽  
Defense Mechanisms ◽  
Abiotic Factors ◽  
Illumina Miseq ◽  
Rrna Gene ◽  
Sequencing Platform ◽  
The Impact

The pandemic Pseudomonas syringae pv. actinidiae (Psa) has been compromising the production of the kiwifruit industry in major producing countries. Abiotic factors and plant gender are known to influence the disease outcome. To better understand their impact, we have determined the diversity of the leafs bacterial communities using the V5-V6 region of the 16S rRNA gene amplicon on the Illumina MiSeq sequencing platform. Healthy and diseased female and male kiwifruit plants were analyzed in two consecutive seasons: spring and autumn. This work describes whether the season, plant gender and the presence of Psa can affect the leaves bacterial community. Fifty bacterial operational taxonomic units (OTUs) were identified and assigned to five phyla distributed by 14 different families and 23 genera. The leaves of healthy female and male kiwi plants share most of the identified bacterial populations, that undergoes major seasonal changes. In both cases a substantial increase of the relative abundance of genus Methylobacterium is observed in autumn. The presence of Psa induced profound changes on leaves bacterial communities structure translated into a reduction in the relative abundance of previously dominant genera that had been found in healthy plants, namely Hymenobacter, Sphingomonas and Massilia. The impact of Psa was less pronounced in the bacterial community structure of male plants in both seasons. Some of the naturally occurring genera have the potential to act as an antagonist or as enhancers of the defense mechanisms paving the way for environmentally friendly and sustainable disease control.

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