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  Research 2024-12-12 JEE 48:48

  Estimation of physical microhabitat suitability for Koreoleptoxis globus (Mollusca: Gastropoda) using probability distribution models

  https://doi.org/10.5141/jee.24.081

  Jin-Young Kim¹ , Jeong-Ki Min² , Ye Ji Kim³ , Yong Su Park¹ and Dongsoo Kong^3*

  [Abstract] Background: Koreoleptoxis globus is an endangered candidate species of snail in South Korean streams. This species primarily inhabits streams characterized by fast current velocities and coarse-particle streambed substrates. In this study, 12 types of probability distribution models, including exponential, normal, log-normal, logistic, Weibull, gamma, beta, and Gumbel, were used to quantitatively assess the physical microhabitat preferences of K. globus. The evaluation was based on data collected from 340 sampling units across 34 sites in South Korea between April 2024 and May 2024, focusing on variables such as water depth, current velocity, and streambed substrate.Results: The best-fitting probability distribution models for each physical environmental factor were identified as follows: 1) water depth, inverted log-normal distribution, 2) current velocity, beta distribution, and 3) streambed substrate, Weibull distribution. Optimal water depth preferences ranged from 31.2 cm to 53.7 cm. Current velocity preferences ranged from 57.8 cm s^-1 to 88.8 cm s^-1. Substrate preferences ranged from −7.4 Φm to −5.6 Φm. The mean values for these factors were water depth of 35.8 cm, current velocity of 63.0 cm s^-1, and streambed substrate of −5.7 Φm. Mode values were water depth of 44.4 cm, current velocity of 75.6 cm s^-1, and substrate of −6.7 Φm. Standard deviation values were water depth of 15.8 cm, current velocity of 21.4 cm s^-1, and streambed substrate of 1.5 Φm.Conclusions: Overall, the beta and Weibull distribution models demonstrated a high degree of fit, likely owing to the inherent flexibility of these models. Beta distribution models were well suited for cases with negative skewness, whereas Weibull distribution models provided a better fit for cases with positive skewness. The physical habitat characteristics of K. globus were quantitatively demontrated to correspond to riffled areas. Further research is required to explore the interactions between physical environmental factors and the impact of habitat disturbance.

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  Research 2024-12-12 JEE 48:47

  Assessing the invasive risk of Procambarus virginalis (marbled crayfish) in South Korea

  https://doi.org/10.5141/jee.24.087

  Hyungsoon Jeong^* and Ju Hui Choi

  [Abstract] Background: Introducing invasive alien species can reduce biodiversity by interfering with native species or spreading disease and having socioeconomic consequences. Therefore, international society has set goals for preventing and suppressing the introduction and spread of invasive alien species. Nevertheless, humans intentionally introduce and release alien species into the wild, facilitating their invasion. Procambarus virginalis (marbled crayfish) is a Decapoda invertebrate sold for ornamental purposes. Ecological repercussions are anticipated because individuals have been verified to exist in the wild in South Korea. P. virginalis, believed to have originated in Europe and North America, is parthenogenetic. Therefore, there is concern that its population may quickly expand in the natural environment.Results: This study examined the invasion risk of P. virginalis in South Korea and predicted its dispersal under future climatic circumstances. The habitat suitability for P. virginalis in Europe, North America, and Northeast Asia was determined using an ensemble species distribution model, and climatic niches were compared. Furthermore, the distributions of South Korea under the SSP2-4.5 and SSP5-8.5 scenarios are provided. The Northeast Asian region had habitat suitability comparable to that of Europe, and there was evidence that its climatic niche overlapped Europe (Schoener’s D = 0.29). In the future climatic scenario, 38% of South Korea is at risk of moderate to low invasion. The human disturbance index was the most critical variable in the distribution.Conclusions: We believe the hazards of its invasion of South Korea are significant. Additionally, there is a high possibility that they will be established in nature due to artificial releases. Therefore, continuous monitoring and appropriate management are needed for areas with a high risk of P. virginalis invasion.

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  Research 2024-12-12 JEE 48:46

  Roles of Chromolaena odorata, macrofauna, and forest edge on the decomposition rate of tree leaf litter in two types of seasonally dry tropical forest

  https://doi.org/10.5141/jee.24.076

  Kasidit Rison¹ , Marut Fuangarworn^2,3 and Chatchawan Chaisuekul^2,3*

  [Abstract] Background: The forest edge of seasonally dry tropical forests (SDTF) is commonly invaded by Chromolaena odorata, which could affect the leaf-litter decomposition (LLD) rate through the litter fauna and the litter chemistry. We tested the effects of positions (edge vs. interior), C. odorata inclusion, and macrofauna inclusion using litterbags containing the two most dominant tree species from each forest type of SDTF (a dipterocarp deciduous forest and a mixed deciduous forest [MDF]), in northern Thailand.Results: The results showed that leaf litter decayed at the same rate between the forest edge and interior. A difference in the decomposition rate between the edge and interior was only found in the MDF and only when the composition of the litter contained a high nitrogen (C. odorata) and phosphorous content (Pterocarpus macrocarpus – a native tree of MDF). Exclusion of macrofauna resulted in slower decomposition rates, but this effect was not significant when combined with the edge condition.Conclusions: Our findings indicated that the forest edge condition has no directly significant effect on the LLD rate but is mediated through changes in the litter chemistry by inclusion of C. odorata litter.

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  Research 2024-11-27 JEE 48:45

  Effect of elevated temperature and water stress on seed germination of the Himalayan medicinal herb Aconitum spicatum

  https://doi.org/10.5141/jee.24.077

  Bishnu Sharma Gaire¹ , Sharada Dhakal¹ , Anjana Devkota^1* , Achyut Tiwari¹ , Babu Ram Paudel² , Uttam Babu Shrestha³ and Bharat Babu Shrestha¹

  [Abstract] Background: Seed germination studies of high mountain plants across environmental gradients are potentially important for understanding the impacts of climate and other environmental changes. In this study, we analyzed the variation in seed germination patterns of the Himalayan medicinal herb Aconitum spicatum across temperature, light, and water stress gradients. Seeds of A. spicatum collected from three different elevations (low: 3,315, mid: 3,910, high: 4,200 m asl) were germinated in a growth chamber under different temperatures (low: 25/15°C; high: 30/20°C), light conditions (12-hour photoperiod and complete dark), and water potentials (−0.10, −0.25, −0.50, −0.75, −1 MPa).Results: Seed mass and germination traits such as germination percentage (GP), mean germination time (MGT) and Timson’s index (TI) did not vary consistently with elevation. While light did not affect germination, high temperatures significantly reduced GP and TI, and increased MGT when compared with low-temperature conditions. The GP declined from approximately 80% at control to less than 20% under mild water stress (−0.50 MPa) with complete inhibition at higher water stress levels. The MGT increased and TI declined with increasing water stress.Conclusions: Our study demonstrated a significant negative impact of elevated temperatures and increased water stress on the germination of A. spicatum, an important medicinal herb of the Himalaya. These findings highlight the species' high vulnerability to the effects of climate change, particularly of the temperature increases and declining precipitation. We suggest incorporating potential impacts of warming and drought into strategies for the sustainable harvest and conservation of A. spicatum in future.

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  Research 2024-11-18 JEE 48:44

  Assemblage and diversity analysis of butterfly species in relation to climatic conditions in some tropical habitats: optimization through artificial neural network model

  https://doi.org/10.5141/jee.24.065

  Subha Shankar Mukherjee and Asif Hossain *

  [Abstract] Background: Biodiversity serves as the foundation for ecosystems and the functional roles of species that supply services to human well-being. The functional roles of species in a region can be assessed by estimating biological diversity. Due to their presence in both aquatic and terrestrial ecosystems, insects have been used as model organisms in several studies, and among insects, butterfly species are considered important model organisms for both ecology and conservation biology. Butterfly species are very sensitive to changes in climatic conditions and serve as important bioindicators for both habitat and climate. For this reason, estimation of butterfly diversity at the spatio-temporal scale is important. On a spatial scale, habitat heterogeneity is believed to be the important factor that plays an important role in maintaining butterfly species diversity, while the differences in diversity of butterfly species on a temporal scale can be linked with climatic conditions both at the regional and local scales.Results: The present study aimed to determine the effects of habitat characteristics and climatic conditions on the diversity of butterfly species in Purulia, India. A total of 83 butterfly species were found during the present study. Out of 83 butterfly species, Nymphalidae dominate over other families (28 species; 33.73%). The highest species richness was observed in the Ajodhya Hill region (61 species), followed by Garh Panchakot (54 species) and Leprosy Mission (47 species). The relative abundance and butterfly species richness differed between sites with different habitat characteristics. Maximum temperature serves as the most sensitive variable for species richness and is negatively related.Conclusions: From this study, it is evident that different habitats in Purulia can sustain a diverse variety of butterfly species, but significant conservation effort is required. So, considering Purulia as a model area, steps must be taken to maintain habitat heterogeneity and local climatic conditions for sustaining ecosystem services provided by butterfly species.

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  Research 2024-11-14 JEE 48:43

  Fire-induced shift from Pinus to Quercus forests: a twenty-year study following the 1996 Goseong forest fire

  https://doi.org/10.5141/jee.24.089

  Yeonsook Choung^1*† , Kyu Song Lee^2† , Hyun Kyung Oh³ , Soyeon Cho⁴ , Youngjin Kim⁵ , Kyungeun Lee⁴ , Jaeyeon Lee⁴ and Sangyeop Jung⁶

  [Abstract] Background: The 1996 Goseong forest fire, the largest recorded, prompted a debate on the potential for natural forest recovery, leading to the designation of a natural restoration research area. This study mainly aimed to demonstrate the forest’s natural regenerative ability in a prefire Pinus densiflora forest that had been affected by a stand-replacing fire. To achieve this, the study tracked the key aspects of the succession process, specifically the formation of vertical structure and changes in species composition.Results: The regenerating vegetation initially passed through stages dominated by herbaceous and shrub layers, then differentiated into the canopy layer, eventually forming the early-stage forest after 20 years. Site A had developed into a forest with an average canopy height of 13.3 m and 73% coverage, while Site B was restored with a canopy height of 10 m and 27% coverage. Tree species of the genus Quercus dominated the canopy layer, occupying 99% of the tree basal area (from 17% prefire). Consequently, the prefire pine forest shifted to a Quercus-dominated forest after secondary succession. Pinus densiflora (83% of the prefire basal area) occupied only 1% after 20 years. Oak species became dominant from the initial stages of regeneration, playing a key role in shaping the early-stage forest structure. The species composition of the regenerating stands was already determined in the initial stage and closely resembled that of 20 years later. Since most species regenerated through resprouting, the understory remained dominated by pine forest companion species. Oak-associated species tended to increase in later stages. No invasive species were observed, and annual plants had low abundance.Conclusions: The study demonstrated the natural regenerative power of the forest following the fire, revealing that it takes around 20 years for a prefire pine forest to be restored an early-stage oak-dominated forest. Quercus trees, particularly Quercus variabilis and Quercus mongolica, regenerated rapidly immediately after fire, contributing to the development of the early-stage forest. Although this study was small in scale, it is a rare study conducted at permanent plots over 20 years, revealing the secondary succession process.

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  Research 2024-11-06 JEE 48:42

  Impacts of invasive weed Chromolaena odorata on growth and development of threatened native tree Aegle marmelos under water stress conditions

  https://doi.org/10.5141/jee.24.072

  Sunita Poudel¹ , Ramesh Raj Pant² , Lal Bahadur Thapa^1* and Mukesh Kumar Chettri³

  [Abstract] Background: The invasive weed Chromolaena odorata has been pronounced in dry habitats in Nepal, where a threatened native tree Aegle marmelos prefers to grow. It is known that the allelochemicals from C. odorata can harm native species differently, however, the impact may depend on environmental factors such as soil moisture in the invaded habitats. This study evaluates how the native tree responds to leaf and root products (leachates) of C. odorata and how water stress influences this interaction. For evaluating these facts, field survey to know the A. marmelos seedling status in C. odorata invaded and uninvaded sites was carried out. The seedlings were also grown in pots by treating the pot soil with C. odorata root and leaf leachates under water-stressed and unstressed conditions. Morphological and biochemical traits (root and shoot length, seedling biomass, leaf and root number, specific leaf area (SLA), photosynthetic pigments and proline) were measured.Results: A significant decrease in A. marmelos seedling population was found within its habitat under the canopy of C. odorata. Root length and biomass of A. marmelos seedlings were decreased by water stress (frequent drought). Addition of C. odorata leaf and root leachates further increased the toxic effects. Similarly, the content of photosynthetic pigments (chlorophylls and carotenoids) was decreased under drought conditions, with C. odorata leachates contributing more to the reduction in chlorophyll amount. The increment of the osmolyte proline in the native seedlings shows the seedlings are experiencing stressful environment.Conclusions: Seedlings of A. marmelos are facing a stressful environment in their habitat invaded by C. odorata. Frequent dryness and exposure of the native seedlings to invasive leachates together can significantly decline the population of threatened native species. Hence, removal of C. odorata from the invaded habitat is recommended before the onset of monsoon season to prevent leaching from its aerial or underground parts to minimize the negative impacts on the growth and development of such a threatened native tree.

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  Research 2024-11-04 JEE 48:41

  The potential of mulberry leaf protein concentrate as a supplementary feed on the health and lifespan of honey bees (Apis mellifera L.)

  https://doi.org/10.5141/jee.24.038

  Khanchai Danmek¹ , Ming-Cheng Wu^2* , Kanokwan Kliathin³ , Ho Lam Ng² , Surat Hongsibsong⁴ , Sampat Ghosh⁵ , Chuleui Jung⁶ and Bajaree Chuttong^3*

  [Abstract] Background: In situations where natural pollen sources are insufficient, it becomes crucial to explore alternative proteins for honey bees. Utilizing mulberry leaf protein concentrate (LPC) emerges as a vital strategy to enhance the nutritional quality of dietary supplements for honey bees, thus mitigating the effects of limited pollen availability. Moreover, it acts as a dietary supplement that positively influences honey bee longevity and health. This study aims to evaluate the effects of incorporating mulberry LPC into honey bee nutritional supplements on maintaining bee health and prolonging their lifespan.Results: Mulberry LPC exhibited high protein content (28.60% ± 3.22%), dry matter (86.55% ± 4.56%), and low levels of fiber (3.16% ± 0.25%), ether extract (3.12% ± 0.25%), and ash (0.71% ± 0.10%), respectively. The essential amino acid composition derived from mulberry LPC revealed elevated values of leucine and lysine, which are necessary for honey bee development. Through a comprehensive investigation of mulberry LPC supplementation in pollen patty on honey bee physiology and life span, the treatment administering 2.5%–5.0% mulberry displayed a significant increase (p < 0.05) in acini sizes and prolonged the life span when compared to the control group fed solely with sucrose syrup.Conclusions: This finding is the first report highlighting the potential of mulberry LPC as a novel supplement feed for honey bees. Mulberry LPC demonstrated notable characteristics, including a high protein content. Furthermore, the essential amino acid composition of mulberry LPC showed elevated levels of leucine and lysine. Our results signify the beneficial impact of mulberry LPC in honey bee nutrition, suggesting its potential as a viable dietary intervention to improve honey bee health and life span. Further research in this domain holds promise for advancing beekeeping practices and ensuring the sustainability of honey bee populations.

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  Research 2024-10-29 JEE 48:40

  Microplastic in the gastrointestinal tract of Bombay duck (Harpadon nehereus) in the Patenga Beach of the Bay of Bengal, Bangladesh: occurrence, abundance, and physicochemical features

  https://doi.org/10.5141/jee.24.016

  Sabah tuz Zohora¹ , Shahida Arfine Shimul¹ , Saifuddin Rana¹ , Antar Sarkar¹ , Sui Naing Aye Marma Milky¹ , Khing Khing U Marma¹ , Kaji Mohammad Sirajum Monir¹ , Farhan Azim¹ , Tapos Kumar Chakraborty² and Sk. Ahmad Al Nahid^1*

  [Abstract] Background: Ingestion of microplastics (MPs) by commercially important fish, such as Bombay duck (Harpadon nehereus) can lead to the transport of MPs to humans and negatively impact health and physiology. Thus, assessment of the presence, type, and features of MP in this species is necessary to understand the possible impacts and adopt management measures. The purpose of this study was to determine the presence, occurrence and physicochemical features of MPs in the gastrointestinal tract of Bombay duck (H. nehereus) from the Patenga Sea Beach of the Bay of Bengal, Bangladesh. This area faces high amount of plastic discharge from the Karnaphuli River, industries, tourists, and urban households. Ninety-six fish were collected from the fishing trawlers of the Patenga Sea Beach. Their total length, body weight was measured and gastrointestinal tracts were separated for analysis. The samples underwent digestion, density separation, measurement, microscopic observation, and quantification. The color, type, and size were observed with microscopic image analysis software and polymer composition was determined with Fourier transform infrared spectroscopy method.Results: The total items of MPs ranged from 25 to 198 per fish with a mean of 98.34 ± 53.11. There was a significant difference in the items of MPs among different sized fish (H = 74.656, p < 0.05). A significant positive correlation (ρ = 0.952, p < 0.05) was found between total length of fish and the number of MPs. Total 05 colors, 04 types and 03 size classes were observed. Filament type, blue color, and 500 μm to < 1 mm sized MPs were dominant. Four (04) types of polymers, polyethylene, polyurethane, polyamide, and polystyrene, were found.Conclusions: The findings and insights from this study will help to understand the nature and extent of MP pollution in commercially important marine fish and possible impacts on the environment and humans.

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  Research 2024-10-29 JEE 48:39

  Enhancing leaf area index estimation in tropical vegetation: a comparative study of multivariate linear regression and Sentinel Application Platform-derived leaf area index

  https://doi.org/10.5141/jee.24.066

  Ali Yasin Ahmed^1* , Abebe Mohammed Ali² , Nurhussen Ahmed² and Birhane Gebrehiwot³

  [Abstract] Background: The leaf area index (LAI) quantifies the total one-sided green leaf area per unit of soil area, making it a crucial parameter in models that simulate carbon, nutrient, water, and energy fluxes within forest ecosystems. This study enhances LAI estimation techniques by employing a multivariate linear regression (MVLR) approach specifically tailored to tropical vegetation. We integrated field-collected LAI data with spectral indices and multispectral bands to develop a robust predictive empirical model. The LAI estimates derived from the MVLR approach are rigorously compared with those obtained from the Sentinel Application Platform (SNAP), a widely utilized tool for remote sensing analysis.Results: In developing the MVLR model, nine multispectral bands, seven vegetation indices (VIs), and two biophysical variables derived from Sentinel-2 multispectral image were tested to identify efficient predictors for LAI estimation. To determine significant multispectral bands and VIs (ensuring no multicollinearity, high coefficient of determination (R²), low root mean square error (RMSE), and a p-value < 0.05) for the best representative model, stepwise multiple linear regression (SMLR) was employed. Multispectral bands 7 and 8, along with the VIs soil adjusted vegetation index and normalized difference vegetation index, and the fraction of vegetation cover biophysical variable, produced superior outcomes and serve as strong predictor variables for LAI. The accuracy of the MVLR model was validated using 17 directly measured LAI sample plots with the leave-one-out cross-validation method. The estimated LAI using the MVLR model achieved higher accuracy, with an R² of 0.94, compared to the SNAP toolbox (R² = 0.71). The RMSE and bias of the MVLR model were 0.18 and 0.006, respectively, while for SNAP-derived LAI, the RMSE and bias were 0.53 and 0.31, respectively.Conclusions: The improved accuracy and reduced error of the MVLR model are attributed to its adjustment for tropical vegetation types. Future research should focus on comparing the MVLR model with other global LAI products to further validate and enhance its applicability.

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  Research 2024-10-14 JEE 48:38

  Evaluating the risk of living modified organisms on the natural ecosystem by analyzing the overwintering potential of four major species imported into Korea

  https://doi.org/10.5141/jee.24.070

  Kyong-Hee Nam^1* , Sung Min Han¹ , Seong-Jun Chun¹ , Jun-Woo Lee¹ and Jihoon Kim^1,2

  [Abstract] Background: Living modified organisms (LMOs) imported into Korea may pose various risks to the domestic natural ecosystem, depending on their seed survival capacity and proliferation potential. In this study, we investigated seed germination and dormancy rates under controlled low temperatures for 12 weeks. In addition, we assessed the overwintering potential of seeds buried at 10 cm soil depth over 48 weeks using non-transgenic seeds of four major LMOs imported into Korea.Results: Brassica napus L. seeds exhibited superior germination and dormancy rates compared to Glycine max (L.) Merr., Zea mays L., and Gossypium hirsutum L. seeds when subjected to incubation at low temperatures (–5°C, –1°C, and 5°C). Seed germination was exclusively recorded for B. napus seeds in the field, which reflects the winter environment, for up to 8 weeks after burial. Seeds of both B. napus and Z. mays remained dormant in the soil for up to 4 weeks after burial; however, G. max and G. hirsutum seeds did not remain dormant. Germination rates were higher when the seeds were placed in seed bags and buried, whereas dormancy rates were higher when the seeds were buried without seed bags.Conclusions: These results suggest that B. napus could have a higher invasive potential than other plant species, which may affect its survival and spread, ultimately posing a greater threat to the ecosystem. This study provides valuable insights into the immediate need for establishing risk assessments and safety management measures for LMOs (specifically B. napus).

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  Research 2024-09-25 JEE 48:37

  Ecological significance of newly recorded halophilic Pharyngomonas kirbyi from two Korean solar salterns

  https://doi.org/10.5141/jee.24.073

  Hyeon Been Lee and Jong Soo Park^*

  [Abstract] Background: Hypersaline environments (> 40 practical salinity units [PSU]) represent some of the most extreme conditions on Earth, supporting a variety of halophilic and halotolerant bacteria, archaea, and protists. The taxon Heterolobosea includes numerous halophilic protists, making it a valuable model for studying eukaryotic adaptation to high salinity. Particularly, the genus Pharyngomonas, a deep-branching lineage within Heterolobosea, comprises mainly obligate halophiles, providing insights into early protist adaptations in hypersaline environments. Additionally, these protozoa play crucial ecological roles as grazers of bacteria and archaea, and are prey for higher trophic levels in hypersaline environments.Results: In the present study, two previously reported amoeboflagellates were isolated for the first time from hypersaline waters (~300 PSU) in two solar salterns in the Republic of Korea. Microscopic observations revealed that both strains exhibited the characteristic morphologies of Pharyngomonas, including amoeboid, flagellate, and cyst forms. Molecular phylogenetic analysis of their 18S rRNA gene sequences confirmed their close relationship to known Pharyngomonas kirbyi strains. The two strains demonstrated growth within a salinity range of 75–200 PSU, with optimal growth observed at 75–100 PSU, confirming their status as true halophiles. All known P. kirbyi strains are obligate halophiles, exhibiting a clear instance of adaptive radiation of halophilic eukaryotes. Additionally, the genus Pharyngomonas has been found in hypersaline environments across multiple continents (Asia, Europe, North America, Australia, and Africa), suggesting that it plays an ecologically significant role as a grazer of prokaryotes or prey for higher trophic levels in these habitats.Conclusions: On the bases of morphological and molecular analyses, two strains identified as P. kirbyi were isolated and characterized for the first time from solar salterns in the Republic of Korea. This discovery highlights the presence and adaptation of halophilic eukaryotes in such extreme environments. The confirmation of these strains as obligate halophiles provides additional evidence for the adaptive radiation of halophilic eukaryotes. Furthermore, the ecological role of Pharyngomonas species underscores their importance as trophic regulators in hypersaline ecosystems. These findings contribute to a deeper understanding of the diversity, adaptation, and ecological functions of halophilic eukaryotes in extreme environments.

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