Abiotic Environmental Conditions Research Articles

Responses of plant stoichiometric niche to locust disturbance with different densities in Inner Mongolia grasslands

Producers, consumers, decomposers and their relationships are all important biological components of a healthy ecosystem. Grasshoppers (including locusts) have been extensively studied as a group of members of grassland ecosystems. However, the effects of different degrees of locust disturbance on plant niches remain unclear. We carried out a field experiment by manipulating locust (Oedaleus asiaticus) grazing at different densities in the Inner Mongolia Grassland Ecosystem Research Station in northern China, to investigate the outcome of locust plague on plant C:N:P stoichiometric niche. Based on the Copula function with improved modelling methods to simulate the stoichiometric niche projection map of different plants, we found that Leymus chinensis and Stipa grandis, after being disturbed by locusts, had a relatively larger niche space and niche overlap among the seven plant species, indicating that they remained the dominant species in the area. Achnatherum sibiricum, Cleistogenes squarrosa, and Koeleria cristata showed little change in their C:N:P stoichiometric niche in response to locust plague, while the mechanisms involving stoichiometric niche variation were not the same in these plants; food importance to locust and physiology (e.g., photosynthesis pathway type) may account for this. Our results suggest that a heavy degree of locust plague might benefit the expansion of chemical niche space (species' niche in chemical resource utilization) in some plants in Inner Mongolian grasslands, but does not necessarily increase their physical niche (species' niche under abiotic environmental conditions like temperature and humidity). To our knowledge, the present work is the first to study C:N:P stoichiometric niche variation in response to locust disturbance and may have significance in theoretical studies and provide guidance for the protection of biodiversity and grassland ecosystem management.

Temporal dynamics in vertical leaf angles can confound vegetation indices widely used in Earth observations

Earth observation data is key for monitoring vegetation dynamics across temporal and spatial scales. The most widely used method to estimate vegetation properties from Earth observation data is vegetation indices. However, temporal dynamics in vertical leaf angles can strongly alter reflectance signals and, hence, vegetation indices. Here, we derive leaf angles from plant photographs to simulate the effect on vegetation indices with radiative transfer models. We show that leaf angle dynamics systematically confound widely applied vegetation indices. Moreover, we demonstrate that these effects are not random but tightly linked to abiotic environmental conditions. These systematic effects of vertical leaf angles have implications for monitoring plant properties, biodiversity, and ecosystem functional properties. We discuss the related challenges and opportunities to assess spatio-temporal vegetation dynamics with remote sensing and vegetation indices.

Impact of Abiotic and Biotic Environmental Conditions on the Development and Infectivity of Entomopathogenic Nematodes in Agricultural Soils.

Many organisms, including beneficial entomopathogenic nematodes (EPNs), are commonly found in the soil environment. EPNs are used as biopesticides for pest control. They have many positive characteristics and are able to survive at sites of application for a long time, producing new generations of individuals. The occurrence of populations depends on many environmental parameters, such as temperature, moisture, soil texture, and pH. Extreme temperatures result in a decrease in the survival rate and infectivity of EPNs. Both high humidity and acidic soil pH reduce populations and disrupt the biological activity of EPNs. Nematodes are also exposed to anthropogenic agents, such as heavy metals, oil, gasoline, and even essential oils. These limit their ability to move in the soil, thereby reducing their chances of successfully finding a host. Commonly used fertilizers and chemical pesticides are also a challenge. They reduce the pathogenicity of EPNs and negatively affect their reproduction, which reduces the population size. Biotic factors also influence nematode biology. Fungi and competition limit the reproduction and survival of EPNs in the soil. Host availability enables survival and affects infectivity. Knowledge of the influence of environmental factors on the biology of EPNs will allow more effective use of the insecticidal capacity of these organisms.

Forgotten Gems: Exploring the Untapped Benefits of Underutilized Legumes in Agriculture, Nutrition, and Environmental Sustainability.

In an era dominated by conventional agricultural practices, underutilized legumes termed "Forgotten Gems" represent a reservoir of untapped benefits with the unique opportunity to diversify agricultural landscapes and enhance global food systems. Underutilized crops are resistant to abiotic environmental conditions such as drought and adapt better to harsh soil and climatic conditions. Underutilized legumes are high in protein and secondary metabolites, highlighting their role in providing critical nutrients and correcting nutritional inadequacies. Their ability to increase dietary variety and food security emerges as a critical component of their importance. Compared to mainstream crops, underutilized legumes have been shown to reduce the environmental impact of climate change. Their capacity for nitrogen fixation and positive impact on soil health make them sustainable contributors to biodiversity conservation and environmental balance. This paper identifies challenges and proposes strategic solutions, showcasing the transformative impact of underutilized legumes on agriculture, nutrition, and sustainability. These "Forgotten Gems" should be recognized, integrated into mainstream agricultural practices, and celebrated for their potential to revolutionize global food production while promoting environmental sustainability.

Studi Keragaman dan Habitat Gastropoda di Daerah Litoral Muara Sungai Ketahun Bengkulu Utara

This research aims to identify the abundance, diversity, dominance and evenness of gastropods at the mouth of the Ketahun River, North Bengkulu. The method used is the "purposive" method. The sampling location was divided into 4 (four) stations, namely in the tidal area and on the right and left in the downstream part of the estuary. The sampling technique uses transects, at each station measuring 20m. Gastropod data analysis uses the Shannon Wiener index, Simpson index, and Pielou index. The research results showed that at the mouth of the Ketahun river, 18 species of gastropods were obtained consisting of 7 genera and 3 families. The diversity index shows, a) station I has an index value of 1.81 (medium category); b) station II has an index value of 0.49 (low category); c) station III has an index value of 1.89 (medium category); d) station IV has an index value of 0.82 (low category). The dominance index shows, a) station I has an index value of 0.23 (low category); b) station II has an index value of 0.70 (medium category); c) station III has an index value of 0.19 (low category); d) station IV has an index value of 0.63 (medium category). The evenness index shows, a) station I has an index value of 0.62 (high category); b) station II has an index value of 0.17 (small category); c) station III has an index value of 0.65 (high category); d) station IV has an index value of 0.28 (small category). The most common gastropod found is the genus Clithon with a total of 1369 individuals. Abundance, diversity, dominance and evenness are determined by abiotic parameters and environmental conditions such as substrate and water quality. Keywords: Bengkulu, Gastropods, Ketahun River

Identification and Expression Analysis of Putative Sugar Transporter Gene Family during Bulb Formation in Lilies.

Sugar transporters play important roles in plant growth and development, flowering and fruiting, as well as responses to adverse abiotic and biotic environmental conditions. Lilies (Lilium spp.) are some of the most representative ornamental bulbous flowers. Sugar metabolism is critical for bulb formation in lilies; therefore, clarifying the amount and expression pattern of sugar transporters is essential for further analyzing their roles in bulb formation. In this study, based on the transcriptome data of the Lilium Oriental hybrid 'Sorbonne' and Lilium × formolongi, a total of 69 and 41 sugar transporters were identified in 'Sorbonne' and Lilium × formolongi, respectively, by performing bioinformatics analysis. Through phylogenetic analysis, monosaccharide transporters (MSTs) can be divided into seven subfamilies, sucrose transporters (SUTs) can be divided into three subgroups, and sugars will eventually be exported transporters (SWEETs) can be divided into four clades. According to an analysis of conserved motifs, 20, 14, and 12 conserved motifs were predicted in MSTs, SUTs, and SWEETs, respectively. A conserved domain analysis showed that MSTs and SUTs contained a single domain, whereas most of the SWEETs harbored two MtN3/saliva domains, also known as a PQ-loop repeat. The LohINT1, which was predicted to have a smaller number of transmembrane structural domains, was cloned and analyzed for subcellular localization. It was found that the LohINT1 protein is mainly localized in the cell membrane. In addition, the expression analysis indicated that 22 LohMSTs, 1 LohSUTs, and 5 LohSWEETs were upregulated in 'Sorbonne' 1 day after scale detachment treatment, suggesting that they may regulate the initiation of the bulblet. A total of 10 LflMSTs, 1 LflSUTs, and 6 LflSWEETs were upregulated 4~6 months after sowing, which corresponds to the juvenile-to-adult transition phase of Lilium × formolongi, suggesting that they may also play a role in the accompanying bulb swelling process. Combined with quantitative real-time PCR (qRT-PCR) analysis, LohSTP8 and LohSTP12 were significantly overexpressed during the extremely early stage of bulblet initiation, and LflERD6.3 was significantly overexpressed during the growth of the underground bulblet, suggesting that they may be key sugar transporters in the formation of lily bulbs, which needs further functional verification.

Effect of weeds on pea (Pisum sativum) seed germination

Segetal vegetation should be controlled both during crop growing season and after harvesting. The reason is that undesirable vegetation accumulates a significant mass, one that will later become a threat to the following crop in crop rotation. Mixtures of substances of biogenic origin, called allopathic, are constantly changing subject to abiotic factors and environmental conditions. Therefore, their effects on organisms are characterized by significant variability. According to the biotesting results, we found that allopathically active substances of all experimental weed species had a negative effect on pea seed germination. In the control variant, all seeds germinated in 4 days, but in some experimental variants 2–3% of the seeds were in the phase of swelling. Water extracts from different species and parts of weeds had significant inhibitory effect on the germination of pea seeds and further growth. The water-soluble extracts from the underground organs of perennial weeds such as Elytrigia repens L. and Cirsium arvense L. were particularly strong, leading to 58.2% and 53.1% reduction in the length of the embryonic root. Water-soluble extracts from the leaves of these weeds had slightly lower effects on pea germination, and the lags in root growth were 33.5% and 31.4%, respectively. Extracts from weed stems also inhibited pea germination and had an intermediate effect between the effect of water-soluble extracts from the underground part and leaf blades. The effect of extracts from roots of annual weeds on the length of the germinal root ranged 36.6% in common stork’s-bill (Erodium cicutarium L.) to 13.9% in chickweed (Stellaria media L.). The allopathic effect of the substances from the leaves of chickweed (Stellaria media L.) and potato weed (Galinsoga parviflora Cav.) had the lowest effect on the growth of pea root. The lag of the indicator in the control was 7.2% and 12.9% for the variants.

The positive plant diversity/consumer relationship is independent of grassland age

Plant diversity is an important driver of many ecosystem processes within and among trophic levels. There is growing evidence that the strength of plant diversity effects depends on the biotic and abiotic environmental conditions. Plant and soil history may be underlying mechanisms of an observed strengthening of biodiversity effects in aging biodiversity experiments. Temporal changes in biodiversity-ecosystem functioning (BEF) relationships have been observed primarily for plants, while dynamics of higher trophic levels are little studied. However, similar patterns can be expected for higher trophic levels because of the close links between producers and consumers. Here, we compare the effects of plant diversity on consumer communities (richness, abundance, diversity, and community composition) and consumer-mediated functions (herbivory and predation) in plant communities with different plant and soil histories. Across six study years, plant diversity had a positive effect on consumer richness, abundance, diversity, and herbivory, whereas the level of predation was not significantly affected by plant diversity. Furthermore, consumer community composition shifted significantly with increasing diversity of plant communities. In addition, consumer abundance, composition, and consumer functions (herbivory and predation) differed between plant communities of different histories. However, contrary to our expectations, plant and soil history caused no significant change in the effects of plant diversity on consumer communities and functions, indicating that these history effects do not provide a mechanistic explanation for plant diversity effects on aboveground invertebrate communities. Thus, our results suggest that plant diversity is a major driver of aboveground invertebrate communities and functions across grassland ages and should be maximized to protect and restore multitrophic biodiversity.

Prediction Model of Flavonoids Content in Ancient Tree Sun−Dried Green Tea under Abiotic Stress Based on LASSO−Cox

To investigate the variation in flavonoids content in ancient tree sun–dried green tea under abiotic stress environmental conditions, this study determined the flavonoids content in ancient tree sun−dried green tea and analyzed its correlation with corresponding factors such as the age, height, altitude, and soil composition of the tree. This study uses two machine−learning models, Least Absolute Shrinkage and Selection Operator (LASSO) regression and Cox regression, to build a predictive model based on the selection of effective variables. During the process, bootstrap was used to expand the dataset for single−factor and multi−factor comparative analyses, as well as for model validation, and the goodness−of−fit was assessed using the Akaike information criterion (AIC). The results showed that pH, total potassium, nitrate nitrogen, available phosphorus, hydrolytic nitrogen, and ammonium nitrogen have a high accuracy in predicting the flavonoids content of this model and have a synergistic effect on the production of flavonoids in the ancient tree tea. In this prediction model, when the flavonoids content was >6‰, the area under the curve of the training set and validation set were 0.8121 and 0.792 and, when the flavonoids content was >9‰, the area under the curve of the training set and validation set were 0.877 and 0.889, demonstrating good consistency. Compared to modeling with all significantly correlated factors (p < 0.05), the AIC decreased by 32.534%. Simultaneously, a visualization system for predicting flavonoids content in ancient tree sun−dried green tea was developed based on a nomogram model. The model was externally validated using actual measurement data and achieved an accuracy rate of 83.33%. Therefore, this study offers a scientific theoretical foundation for explaining the forecast and interference of the quality of ancient tree sun−dried green tea under abiotic stress.

The Impact of Adjacent Road on Vascular Plant Species Composition in Herbaceous Layers of Peucedano-Pinetum and Tilio-Carpinetum Urban Forests in the City of Warsaw (Poland)

The research was conducted in two types of urban forests: Peucedano-Pinetum and Tilio-Carpinetum. The aim of the study was to determine the differences in plant species compositions in the herbaceous layer of urban forests with different habitat fertility adjacent to the road in the northern part of Warsaw (Poland). Seven transects were laid out in each type of forest, with 10 plots spread out from the edge zone (forest border) to the interior of the forests. The size of each plot was 100 m2. The other seven transects were located within the forest, 150 to 200 m away from the forest’s edge. The field research included phytosociological relevés carried out on the existing transects. The indoor studies included an analysis of forest community disturbance. Furthermore, an analysis of abiotic environmental conditions using ecological indicator numbers was carried out. Ecotones of Peucedano-Pinetum are more likely to be colonized by the species inconsistent with the habitat due to processes that increase habitat fertility. The Tilio-Carpinetum forest is more easily colonized by invasive plant species than the Peucedano-Pinetum. The range of road effects can be determined as an area located within 90 m inward of the forest in the case of the Peucedano-Pinetum community and 100 m in the case of the Tilio-Carpinetum community. The presented research is important for formulating directions about how to manage the forests and their surroundings in terms of shaping forests of more natural character, with species more consistent with a forest habitat.

The externality cost of environmental (dis)amenities in the urban housing market: an emerging evidence from Pakistan

ABSTRACT Rising urbanization on abiotic environmental conditions in housing units is one of the most severe difficulties that city municipality authorities face, all over the world. Waste production has increased as a result of households failing to implement waste management strategies that ensure sustainability. Thus, property values in the housing market have regularly deteriorated as a result of environmental (dis)amenities. The study examines the impact of a waste dump site on proximate property values in Pakistan’s twin cities. Using a systematic random sampling technique, questionnaires were distributed to 849 households. 35 dump sites were chosen from 100 metres to 500 metres. The dump sites were chosen based on their size and proximity to residential homes in the study area. The empirical results show that the distance between a residential property and a waste dump site significantly impacts rental values. Moreover, rents exhibit a negative relationship with increasing distance from the dump sites. Based on applied findings, more proactive enforcement of sanitary laws and regulations, such as removing all irregular dump sites from residential areas, is recommended.

Extinction risk modeling predicts range-wide differences of climate change impact on Karner blue butterfly (Lycaeides melissa samuelis)

The Karner blue butterfly (Lycaeides melissa samuelis, or Kbb), a federally endangered species under the U.S. Endangered Species Act in decline due to habitat loss, can be further threatened by climate change. Evaluating how climate shapes the population trend of the Kbb can help in the development of adaptive management plans. Current demographic models for the Kbb incorporate in either a density-dependent or density-independent manner. We instead created mixed density-dependent and -independent (hereafter “endo-exogenous”) models for Kbbs based on long-term count data of five isolated populations in the upper Midwest, United States during two flight periods (May to June and July to August) to understand how the growth rates were related to previous population densities and abiotic environmental conditions, including various macro- and micro-climatic variables. Our endo-exogenous extinction risk models showed that both density-dependent and -independent components were vital drivers of the historical population trends. However, climate change impacts were not always detrimental to Kbbs. Despite the decrease of population growth rate with higher overwinter temperatures and spring precipitations in the first generation, the growth rate increased with higher summer temperatures and precipitations in the second generation. We concluded that finer spatiotemporally scaled models could be more rewarding in guiding the decision-making process of Kbb restoration under climate change.

МОРФОЛОГИЧЕСКИЕ ПРИЗНАКИ ВЕГЕТИРУЮЩИХ САЖЕНЦЕВ ТЕХНИЧЕСКИХ СОРТОВ ВИНОГРАДА СЕЛЕКЦИИ ВНИИВИВ ИМ. Я.И. ПОТАПЕНКО

Evaluation of morphological characteristics of vegetative grapevine seedlings of white-berry varieties of technical direction of use bred by ARRIV&W. Varietal phenotype description was made using the Test Method for Distinctness, Uniformity and Stability of Grapes (Vitis L.) and the OIV descriptor, a descriptive guide for cod-ing ampelographic traits and properties of any phenotypic individual of grapevine. Screening of morpho-biological traits was carried out in the conditions of the northern zone of viticulture (Rostov region). A description of the morpholog-ical characteristics of vegetative seedlings of the most common vine varieties resistant to biotic and abiotic environmental conditions, bred by ARRIV&W named after Ya.I. Potapenko − Pla-tovsky (ZHemchug Zala × Podarok Magaracha), Stanichny (Cvetochnyj × ZHemchug Zala), Cvetochnyj (Severnyj × muscat pollen blend of Muskat vengerskij, Muskat belyj, Muskat ale-ksandrijskij). The varieties are included in the State Register of Selection Achievements Ap-proved for Use. Grafted culture, rootstock Ber-landieri × Riparia Kober 5BB. Screening of mor-phological features of grafted vine seedlings was carried out with a shoot length of 50−70 cm. In accordance with the methodology, the main ob-jects of description were: the top of a young shoot, a shoot, a young leaf and a formed leaf. Using a morphological description of the vegeta-tive parts of growing seedlings, the identification of morphological features was carried out in ac-cordance with international requirements. The scientific novelty of the work is in the fact that the morphological features of vegetative vine seedlings associated with the varietal genotype are described. The information obtained as a re-sult of the assessment makes it possible to identi-fy the described vine varieties by morphological characteristics during the approbation of nursery to create pure-varietal plantations.

Medicinal Importance and Phytoconstituents of Underutilized Legumes from the Caesalpinioideae DC Subfamily

Underutilized legumes are common crops in developing countries with superior dietary potentials that could be useful sources of protein as well as some phytoconstituents. They are more tolerant of abiotic environmental conditions like drought than the major legumes. This makes them more adapted to harsh soil and climatic conditions, which helps to minimize the pressure brought on by climate change. However, despite their potential, underutilized legumes have been greatly overlooked compared to the major legumes due to supply constraints. Underutilized legumes in the subfamily Caesalpinioideae are better suited for use as animal feeds with little or no value as food for humans, and the extracts and infusions of the different parts of plant species in this subfamily are traditionally used for the treatment of different diseases. In addition, underutilized legumes in this subfamily contain phytoconstituents that are of pharmacological relevance, some of which have been isolated, characterized and evaluated for use in the treatment of a variety of disorders. Therefore, this review describes the medicinal activities of some selected underutilized legumes from five genera in the subfamily Caesalpinioideae as well as their phytoconstituents, which could be exploited as lead compounds for drug discovery.

The halophilic bacteria Gracilibacillus dipsosauri GDHT17 alleviates salt stress on perennial ryegrass seedlings.

Adverse abiotic environmental conditions including excess salt in the soil, constantly challenge plants and disrupt the function of plants, even inflict damage on plants. Salt stress is one of the major limiting factors for agricultural productivity and severe restrictions on plant growth. One of the critical ways to improve plant salt tolerance is halotolerant bacteria application. However, few such halotolerant bacteria were known and should be explored furtherly. Halophilic bacterium strain was isolated from saline soil with serial dilution and identified with classical bacteriological tests and 16S rRNA analysis. Perennial ryegrass (Lolium perenne L) was used in this study to evaluate the potential effect of the bacteria. A halophilic bacterium strain GDHT17, was isolated from saline soil, which grows in the salinities media with 1.0%, 5.0%, and 10.0% (w/v) NaCl, and identified as Gracilibacillus dipsosauri. Inoculating GDHT17 can significantly promote ryegrass's seedling height and stem diameter and increase the root length, diameter, and surface area at different salt concentrations, indicating the significant salt stress alleviating effect of GDHT17 on the growth of ryegrass. The alleviating effect on roots growth showed more effective, especially on the root length, which increased significantly by 26.39%, 42.59%, and 98.73% at salt stress of 100 mM, 200 mM, and 300 mM NaCl when the seedlings were inoculated with GDHT17. Inoculating GDHT17 also increases perennial ryegrass biomass, water content, chlorophyll and carotenoid content under salt stress. The contents of proline and malonaldehyde in the seedlings inoculated with GDHT17 increased by 83.50% and 6.87%, when treated with 300 mM NaCl; however, the contents of MDA and Pro did not show an apparent effect under salt stress of 100 mM or 200 mM NaCl. GDHT17-inoculating maintained the Na+/K+ ratio in the salt-stressed ryegrass. The Na+/K+ ratio decreased by 26.52%, 6.89%, and 29.92% in the GDHT17-inoculated seedling roots treated with 100 mM, 200 mM, and 300 mM NaCl, respectively. The GDHT17-inoculating increased the POD and SOD activity of ryegrass seedlings by 25.83% and 250.79%, respectively, at a salt stress of 300 mM NaCl, indicating the properties of GDHT17, improving the activity of antioxidant enzymes of ryegrass at the salt-stress condition. Our results suggest that G. dipsosauri GDHT17 may alleviate salt stress on ryegrass in multiple ways; hence it can be processed into microbial inoculants to increase salt tolerance of ryegrass, as well as other plants in saline soil.

Several Characteristics of Ecological Factors in the Rafflesiaceae in Indonesia

Rafflesiaceae is a parasitic family that depends on other plants as its host in the form of lianas Tetrastigma sp. which comes from the Vitaceae family (grapes). Rafflesiaceae has three members of the genus including Rafflesia, Rhizanthes, and Sapria. As an obligate parasitic plant, the host conditions originating from environmental conditions greatly affect the condition of this plant. The abiotic components that are measured are usually climatic factors, edaphic factors, and topographical factors. Abiotic factors measured and observed in the field can be used for ex situ germination of parasitic plants. This article was created to serve as a guide regarding data on environmental factors affecting plants from the Rafflesiaceae family in Indonesia. A systematic Literature Review (SLR) uses in this paper. Several plants from the Rafflesiaceae family live in almost homogeneous abiotic environmental conditions. The differences in each species are not too significant even though they are on different islands

Presence of microbiome decreases fitness and modifies phenotype in the aquatic plant Lemna minor.

Plants live in close association with microbial organisms that inhabit the environment in which they grow. Much recent work has aimed to characterize these plant-microbiome interactions, identifying those associations that increase growth. Although most work has focused on terrestrial plants, Lemna minor, a floating aquatic angiosperm, is increasingly used as a model in host-microbe interactions and many bacterial associations have been shown to play an important role in supporting plant fitness. However, the ubiquity and stability of these interactions as well as their dependence on specific abiotic environmental conditions remain unclear. Here, we assess the impact of a full L. minor microbiome on plant fitness and phenotype by assaying plants from eight natural sites, with and without their microbiomes, over a range of abiotic environmental conditions. We find that the microbiome systematically suppressed plant fitness, although the magnitude of this effect varied among plant genotypes and depended on the abiotic environment. Presence of the microbiome also resulted in phenotypic changes, with plants forming smaller colonies and producing smaller fronds and shorter roots. Differences in phenotype among plant genotypes were reduced when the microbiome was removed, as were genotype by environment interactions, suggesting that the microbiome plays a role in mediating the plant phenotypic response to the environment.

The relative importance of abiotic and biotic environmental conditions for taxonomic, phylogenetic, and functional diversity of spiders across spatial scales

Both abiotic and biotic conditions may be important for biodiversity. However, their relative importance may vary among different diversity dimensions as well as across spatial scales. Spiders (Araneae) offer an ecologically relevant system for evaluating variation in the relative strength abiotic and biotic biodiversity regulation. We quantified the relative importance of abiotic and biotic conditions for three diversity dimensions of spider communities quantified across two spatial scales. Spiders were surveyed along elevation gradients in northern Sweden. We focused our analysis on geomorphological and climatic conditions as well as vegetation characteristics, and quantified the relative importance of these conditions for the taxonomic, phylogenetic, and functional diversity of spider communities sampled across one intermediate (500 m) and one local (25 m) scale. There were stronger relationships among diversity dimensions at the local than the intermediate scale. There were also variation in the relative influence of abiotic and biotic conditions among diversity dimensions, but this variation was not consistent across spatial scales. Across both spatial scales, vegetation was related to all diversity dimensions whereas climate was important for phylogenetic and functional diversity. Our study does not fully support stronger abiotic regulation at coarser scales, and conversely stronger abiotic regulation at more local scales. Instead, our results indicate that community assembly is shaped by interactions between abiotic constrains in species distributions and biotic conditions, and that such interactions may be both scale and context dependent.

Using a novel coagulant as a practical and sustainable approach for cyanobacterial bloom control

Excessive cyanobacterial growth, cyanobacterial blooms, occurs in eutrophic water bodies, and coagulants are used to settle down or float up cyanobacterial cells for their removal. In this study, we developed a novel inorganic coagulant, MC, and investigated its practical applicability by treating three water samples from natural reservoirs and compared its efficiency with loess which is a commonly used cyanobacteria-controlling material. To understand how the coagulated cyanobacterial flocs induce water quality changes, each treated-column was exposed to various abiotic environmental conditions (water temperature, pH, dissolved oxygen, light, and water cycle). The chlorophyll-a reduction efficiency of MC was 88%–95% whereas loess showed 37%–57% efficiency. Nutrient concentration increased over time following exposure to environmental conditions. From microcystin and cell integrity tests, MC-treated cyanobacterial cells were damaged two days after the addition, regardless of the conditions, whereas loess-treated cells were damaged only at 40 °C, pH 11, and under aerobic conditions (dissolved oxygen >5 mg L−1). However, the results from an additional experiment revealed that no microcystin was detected from the coagulated cyanobacterial floc removed column, while total nitrogen and total phosphorus concentrations were reduced by 90% and 80%, respectively, than the initial values. On the other hand, in the column with the remaining coagulated cyanobacterial floc, the microcystin started to increase from day 2 of the coagulation and reached almost 1 ppb on day 12. Our study suggests that the use of MC is a practical and sustainable approach for removing cyanobacteria and managing eutrophication in natural water bodies and immediate removal of coagulated cyanobacterial flocs should be accompanied to avoid water contamination via cell damage.

Local stochastics and ecoclimatic situation shape phytophagous chafer assemblage composition.

Very little is known about factors determining the assemblage structure of megadiverse polyphagous-herbivore scarab chafers in the tropics (Coleoptera: Scarabaeidae). Here, we examined the composition of Sri Lankan chafer assemblages and investigated whether it is influenced more by the general ecoclimatic situation, macrohabitat, or indetermined stochastic biotic and abiotic factors of each locality. We also explored the influence of the latter on separate lineages and general body size. Based on dedicated field surveys conducted during the dry and wet seasons, we examined 4847 chafer individuals of 105 species sampled using multiple UV-light traps in 11 localities covering different forest types and altitudinal zones. Assemblages were assessed for compositional similarity, species diversity, and abundance within four major eco-spatial partitions: forest types, elevational zones, localities, and macrohabitats. Our results revealed that assemblages were shaped mainly by locality stochastics (i.e., multi-factor ensemble of all biotic and abiotic environmental conditions at local scale), and to a minor extent by ecoclimatic conditions. Macrohabitat had little effect on the assemblage composition. This was true for the entire chafer assemblage as well as for all single lineages or different body size classes. However, in medium and large species the contrasts between localities were less pronounced, which was not the case for individual lineages of the assemblage. Contrasts of assemblage similarity between localities were much more evident than those for forest types and elevation zones. Significant correlation between species composition and geographic distance was found only for the assemblage of small-bodied specimens. Seasonal change (dry-wet) in species composition was minor and only measurable in a few localities. The strong turnover between examined localities corroborates with the high degree of endemism in many phytophagous chafers, particularly in Sericini. Connected with their hypothetic poor habitat specificity and polyphagy, this might also explain why so many chafer crop pests in the Asian tropics are endemics.