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  Research 2025-03-18 JECOENV 49:09

  Rapid ecosystem services assessment to support integrated coastal zone management mangroves management plan in Solomon Islands

  https://doi.org/10.5141/jee.24.074

  Hyun-Ah Choi^1,2 , Cholho Song² , Chul-Hee Lim³ , Sangin Kang⁴ , Mary Tahu Paia^5* and Donguk Han^6*

  [Abstract] Background: This study focused on assessing ecosystem services in the Solomon Islands, highlighting their significance and challenges. We evaluated the importance of mangrove management using the Rapid Assessment Wetland Ecosystem Services method and the need for integrated conservation efforts to sustain these valuable ecosystems.Results: This study assessed the first qualitative ecosystem services in the Solomon Islands with multi-stakeholders. The assessment revealed significant benefits from ecosystem services in the Solomon Islands, particularly in provisioning fresh water, food, and cultural services. However, challenges such as illegal logging and degradation threaten these benefits, reducing the effectiveness of ecosystem services. We also identified the importance of mangrove management and the need for integrated conservation efforts to sustain these valuable ecosystems.Conclusions: We identified the significance of ecosystem services in the Solomon Islands. This study can help decision-makers in the Solomon Islands determine and ensure the sustainable management of mangrove areas and broader ecosystems.

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  Research 2025-03-11 JECOENV 49:08

  The impact of fertilizing Swietenia mahagoni (L.) Jacq. seedlings under water stress with various nitrogen and phosphorous sources

  https://doi.org/10.5141/jee.24.113

  Dalia Abd El-Azeem Ahmed^1* , Ahmed Sharaf El-Din¹ , Ahmed Abd EL-Dayem² , Mohamed Motawee² and Mohamed EL-Atreby²

  [Abstract] Background: Drought represents a significant global threat, affecting agricultural productivity and leading to water shortages. Nitrogen (N) and phosphorus (P) are essential macronutrients that promote plant growth and enhance tolerance to drought. Swietenia mahagoni (L.) Jacq. (mahogany), is a high-quality timber species recognized for its extensive commercial and pharmaceutical applications. The present study aims to study the effect of fertilization by different forms of N and P on the growth and drought tolerance of mahogany seedlings.Results: The application of three levels of soil water regime (100%, 75%, and 50%, field capacity [FC]) on mahogany seedlings, with different combinations of N fertilizers (ammonium sulfate [AS], ammonium nitrate [AN], and urea [UR]) and P (phosphoric acid [PA], superphosphate [SP], and triple superphosphate [TS]) in two seasons, indicating that the water regimes and all the combinations of N and P forms significantly increased mahogany growth (number of leaves, root length, stem height, the fresh and dry weights of shoots, roots, stem, and leaves), water use efficiency (WUE), and N and P leaves content. The highest values were obtained from irrigation with 100% FC, while the lowest was from 50% FC. All combinations of N and P significantly enhance all growth parameters compared to the control. Furthermore, AS, PA, and AS-PA had significantly the highest values of all studied characteristics. While AN, SP, and AN-TS had the lowest values. The interaction between different water regimes and different N and P combinations had a highly significant (p ≤ 0.001) effect on WUE, root length, leaves dry weight, and N leaf content in both growing seasons. While fresh and dry weights of stem and shoots were significant at p ≤ 0.05 in the second growing season.Conclusions: Drought stress had a negative impact on all vegetative characteristics, WUE, and N and P leaves content of mahogany seedlings. All the combinations of N and P significantly improved growth characteristics under drought conditions, but the most effective treatments were AS, PA, and AS-TS. The present study is very important in that it provides critical insights for enhancing drought adaptation, reducing water usage, and enhancing plant growth characteristics.

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  Research 2025-03-11 JECOENV 49:07

  Selecting indicator-diatom taxa and its application for simplifying trophic diatom index for biological water quality assessment

  https://doi.org/10.5141/jee.24.095

  Seoung Min Kim¹ and Jung Ho Lee^2*

  [Abstract] Background: Trophic diatom index (TDI) should have been conducted annually by ‘water environment conservation act’ since 2008 in South Korea. However, its application had difficulties in identification such as fine structures and diversity of diatoms. In this study, it is proposed that a new water quality assessment method called simplified-TDI (S-TDI) for reducing the difficulties of identification using indicator-diatom taxa.Results: The indicator-diatom taxa were selected using relative abundance and frequency of occurrence. The one criterion was above 10% of the minimum relative abundance of diatom species occurred in each station and the other was above 2% of the minimum frequency of occurrence of diatoms among the total station. Appeared species in 1,999 stations for study was 412 and 115 species were selected as the indicator-diatom taxa. The criterions were verified using statistic assessment method as below similarity, paired sample t-test and root mean square error (RMSE). Species excluded from indicator-diatom taxa were identified two methods. They were identified up to genus level and received the average sensitivities and indicator values of the genus in TDI. Even they were not able to be identified genus level, identified them to “unidentified group” and received the average sensitivities and indicator values of total diatom species in TDI. This method was newly proposed as S-TDI in this study. To verify the application of S-TDI, its values were compared with original TDI values from 60 sampling stations considering various aquatic environments. The similarity between S-TDI and original TDI values were very high degree of 0.999, the paired sample t-test indicated no statistically significant difference and RMSE was 1.52 below the threshold.Conclusions: These results showed S-TDI can be applied to the water quality assessment instead of original TDI.

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  Research 2025-03-10 JECOENV 49:06

  Assessment of carbon-biodiversity change from forestry projects in Republic of Korea

  https://doi.org/10.5141/jee.24.108

  Heon Mo Jeong , Inyoung Jang , Chul-Hyun Choi , Sanghak Han and Sung-Ryong Kang^*

  [Abstract] Background: This study was undertaken to analyze the impact of reforestation and logging (i.e., forestry projects) on forest carbon stocks and biodiversity. Vegetation and biodiversity data were utilized from areas where forestry projects were implemented to estimate changes in carbon stocks and biodiversity before and after forestry projects. The carbon-biodiversity linkage assessment was developed by indexing carbon stocks and biodiversity in the same ratio.Results: A high carbon-biodiversity linkage assessment index indicates high carbon stocks and biodiversity. Forestry projects were found to have a negative impact on both carbon stocks and biodiversity. Significant reductions in tree above-ground and soil carbon stocks and biodiversity declines of mast taxonomic groups were observed. However, due to differences in ecosystem characteristics, the magnitude of biodiversity decline varied among taxa. A decline following forestry projects was demonstrated as a result of the carbon-biodiversity linkage assessment. A decrease in the carbon-biodiversity linkage index indicates a weakening of ecosystem services, climate change reduction, and mitigation functions of the target area. Through carbon-biodiversity linkage assessment, this study identified hotspot areas with high carbon stocks and biodiversity.Conclusions: These areas of concern can provide a policy basis information for simultaneously increasing and conserving carbon storage capacity and biodiversity in Korea. Therefore, we recommend an ecosystem survey database that is consistent in time and space should be established and managed for accurate carbon-biodiversity linkage assessment. It is also necessary, depending on ecosystem type and environmental impacts, to investigate the synergy and trade-offs between carbon stocks and biodiversity.

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  Review 2025-03-06 JECOENV 49:05

  A review of remote sensing applications in flower phenology detection

  https://doi.org/10.5141/jee.24.118

  Ehsan Rahimi and Chuleui Jung^*

  [Abstract] The shift in flowering phenology with plants blooming earlier due to climate change, disrupts the synchronization between plants and pollinators by creating temporal and spatial mismatches. Monitoring these shifts is essential, and remote sensing has become an invaluable tool for detecting flowering periods over vast areas. Despite the technological advancements, there remains a significant gap in comprehensive reviews that explore the use of remote sensing in flowering phenology and its impact on pollination ecology. Therefore, this study aims to review and summarize research on the remote sensing of flowers, with a particular focus on key techniques used to analyze flowering phenology. We categorized the application of remote sensing in the field of flowering phenology into four groups based on the type of data used: optical, Synthetic Aperture Radar (SAR), Unmanned Aerial Vehicle (UAV), and PhenoCam-based applications. In each section, we have reviewed and provided a summary of the studies conducted in this field, with a particular focus on those that primarily examine canola crop flowering. In conclusion, our findings reveal that Optical remote sensing, proves effective in capturing detailed imagery of flowering events, while SAR technology offers robust, all-weather monitoring capabilities. UAV-based remote sensing provides high-resolution, site-specific data, although it is constrained by operational limitations. PhenoCams offer valuable long-term monitoring but lack the spatial resolution for detailed analysis. Each remote sensing approach has distinct advantages and limitations, underscoring the need for integrated methods to improve flowering phenology assessments and enhance agricultural monitoring.

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  Review 2025-02-21 JECOENV 49:04

  Variation in Q₁₀ of soil respiration due to biophysical factors in forest ecosystems

  https://doi.org/10.5141/jee.24.096

  Angom Sarjubala Devi *, Mary Lalremruati , Gospel Lallawmzuali , Naorem Twinkle Devi , Vanlalhmuaka , Khumujam Omeshori Devi and Khumallambam Jyotish

  [Abstract] Background: Sensitivity of forests to atmospheric warming is greater when compared with other types of landuse. Evaluation on response of soil respiration to increase in temperature is valuable as forest soils emits 75 to 77 PgC yr^-1. Sensitivity of soil respiration to climate change varies from a forest to another forests, therefore evaluation of Q₁₀ is necessary to provide an unbiased result.Results: In the present compilation it was found that as latitude increases Q₁₀ of forests rises and it correlated negatively with mean annual temperature (MAT) and mean annual precipitation (MAP). The amount of soil organic carbon (SOC) does not correlate with Q₁₀ however, higher amount of recalcitrant C and associated microbial population in forest soils at higher latitudes as a result of low MAT and MAP is an important factor in the elevated response of Q₁₀.Conclusions: The quality of SOC and not the quantity of SOC is an important component in estimating sensitivity of soil respiration to increase in temperature in different forests.

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  Research 2025-02-20 JECOENV 49:03

  Characteristics of natural habitats of an endangered species, Cymbidium macrorhizon

  https://doi.org/10.5141/jee.24.109

  Jeong Sook Hwang¹ , Jong Hyun Kim¹ , Hye Jung Bang¹ , Dae Shin Kim² and Yeon Sik Choo^3*

  [Abstract] Background: A leafless, partially mycoheterotrophic terrestrial orchid Cymbidium macrorhizon is legally protected as Endangered Species in Korea, but there is insufficient information on the habitat and growth conditions of this species to ensure its conservation. We conducted a survey of the occurrence and growth of C. macrorhizon from June to November 2024 on Mt. Noza in Geoje, and in Jeju during July and September. We also examined the vegetation, canopy coverage, soil respiration rate, and soil physicochemical parameters in C. macrorhizon habitats. To understand the factors influencing the survival and reproductive success of C. macrorhizon, we analyzed the relationships between population size and the surrounding vegetation, as well as soil physicochemical parameters.Results: In both Geoje and Jeju, C. macrorhizon can be observed from late June to early November, with the highest emergence occurring in July. However, less than 3% of the fruits were continuously maintained and reached fruit maturity. Cymbidium macrorhizon was observed with more than 20 individuals in the Pinus thunbergii and Platycarya strobilacea communities. The results of the Principal Component Analysis indicated that the P. thunbergii community is associated with soil characteristics such as organic matter content, water content, and pH. The successful progression of C. macrorhizon through its growth stages, including flowering, fruiting, and fruit maturation, was primarily observed in areas with adequate light penetration, specifically where light levels reached up to a relative light intensity of 56% with a maximum of about 5,300 lux, rather than those excessively shaded by the canopy.Conclusions: Cymbidium macrorhizon forms large populations, especially in P. thunbergii stands, which are characterized by well-developed organic layers and well-drained soils with approximately 40% soil moisture content. It is proposed that C. macrorhizon may increase its population size through vegetative propagation via rhizomes facilitated by microbial activity in environments that limit population growth through seed reproduction, such as shaded stands with high organic matter content. Understanding the specific environmental conditions, such as soil characteristics and light penetration, and vegetation community in its natural habitat, can provide crucial data for establishing effective conservation strategies to ensure the continued survival and proliferation of C. macrorhizon.

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  Research 2025-02-13 JECOENV 49:02

  Local scale variations in soil organic carbon sequestration in Lesser Himalayan coniferous and mixed forests: implications for sustainability

  https://doi.org/10.5141/jee.24.088

  Raja Waqar Ahmed Khan *, Maryam Quratulain , Hamayun Shaheen *, Karamit Hussain and Abdul Basit Mehmood

  [Abstract] Background: Soil carbon sequestration is a fundamental mechanism for mitigating climate change by capturing carbon dioxide from the atmosphere. Soils can store more carbon than both vegetation and the atmosphere combined. This study aims to quantify the organic carbon stock and evaluate various physicochemical properties of the soil to promote sustainability in the Lesser Himalayan subtropical coniferous and mixed forests of Muzaffarabad. Soil samples were collected from ten representative sites within each forest type, and soil organic carbon (SOC) was measured using the Walkley-Black method.Results: The SOC averaged 63.86 ± 3.29 Mg ha^-1 in coniferous forests and 50.05 ± 3.05 Mg ha^-1 in mixed forests, with a total average of 56.95 ± 1.40 Mg ha^-1. SOC levels in coniferous forest soils ranged from 82.11 ± 6.52 Mg ha^-1 to 48.63 ± 3.82 Mg ha^-1, while mixed forest ecosystems exhibited a SOC range of 62.29 ± 4.71 Mg ha^-1 to 35.57 ± 2.34 Mg ha^-1. The average soil pH was 7.1 ± 0.14, whereas soil bulk density, and electrical conductivity were 1.1 ± 0.01 g cm^-3 and 0.95 ± 0.07 dS m^-1, respectively. The sampled forests harboured 103 plant species from 48 families and 92 genera, with trees, shrubs, and herbaceous plants constituting 17%, 12%, and 71% of the flora, respectively.Conclusions: Statistical analysis revealed a significant difference in SOC between coniferous and mixed forest types. The dominant plant families in the studied forests were Poaceae, Compositeae, Fabaceae, and Lamiaceae. The findings underscore the need for sustainable forest and soil management policies to enhance SOC levels. Implementing such policies is crucial for achieving the sustainable development goals related to environmental sustainability, economic development, and societal well-being.

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  Research 2025-01-17 JECOENV 49:01

  Using ecological niche modeling to model invasion risk of hornets (Hymenoptera: Vespidae) in Iran

  https://doi.org/10.5141/jee.24.071

  Ehsan Rahimi¹ and Chuleui Jung^1,2*

  [Abstract] Background: Among the 22 species in the Vespa genus, five have successfully established populations outside their native ranges, while four others have been recorded either in natural habitats or during border inspections in various countries. This study aims to assess the potential threat posed by 12 hornet species—Vespa crabro, Vespa mandarinia, Vespa simillima, Vespa velutina, Vespa affinis, Vespa analis, Vespa basalis, Vespa bicolor, Vespa ducalis, Vespa dybowskii, Vespa soror, and Vespa tropica—within the geographical and ecological context of Iran, an arid Middle Eastern country. Using ecological niche modeling, we analyzed species occurrence data alongside climatic variables with minimal correlation to predict the potential distribution of these hornets across Iran. The mobility-oriented parity method was applied to identify areas where strict extrapolation is relevant for these species. Additionally, we generated a habitat suitability map for Apis mellifera (honey bee) using ecological niche modeling and compared the spatial overlap between the predicted risk maps for the hornets and the honey bee habitat suitability map, employing Schoener’s D metric.Results: The results revealed two key findings. First, a significant portion of Iran exhibits climatic dissimilarity compared to the native habitats of certain hornet species. Second, the spatial overlap analysis showed varying degrees of overlap between A. mellifera habitats and the potential distributions of different hornet species. Notably, V. mandarinia and V. crabro demonstrated the highest overlap values (D = 0.68), suggesting that these hornets could share substantial habitat preferences or ecological roles with honey bees in Iran.Conclusions: Although most regions of Iran appear less suitable for hornet invasions, caution is warranted in the northern areas, where trade and exchanges could serve as pathways for Vespa hornet introductions. These findings highlight the importance of targeted monitoring and preventative measures in these high-risk regions.

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  Research 2024-12-19 JECOENV 48:50

  Spatiotemporal comparison of fatty acid profiles of four gastropod species in aquatic fields in Korea

  https://doi.org/10.5141/jee.24.080

  Dongwoo Yang¹ and Sangkyu Park^2*

  [Abstract] Background: Gastropods as primary consumer serve the principal ecological function of transporting nutrients and energy from food sources, such as phytoplankton and periphyton, to higher trophic levels in aquatic environments. In addition to their ecological roles, freshwater gastropods have long been used by humans in Korea. Owing to biosynthesis constraints, animals must consume important components, including fatty acids, from their diet. Thus, the fatty acid composition of consumers reflects that of their diets. To determine the patterns of fatty acid accumulation in gastropods in coexisting aquatic habitats, we conducted a spatiotemporal study on the fatty acid composition of four freshwater gastropods associated to humans collected from reservoirs, rivers, and rice paddy fields in Korea.Results: Our results showed that the four gastropod species [Chinese mystery (Cipangopaludina chinensis malleata), melanian (Semisulcospira gottschei), European ear (Radix auricularia), and golden apple (Pomacea canaliculata) snails] had differentiated fatty acid compositions according to sampling site based on the result of cluster analysis. Furthermore, principal component analysis showed that coexisting gastropods displayed intraspecific variations in fatty acid profiles, even when inhabiting same areas and were provided similar potential food sources. By comparing biomarkers, it appears that fatty acid accumulation patterns in gastropods are affected by their feeding strategies.Conclusions: Taxonomic variations in fatty acid composition can be attributed to competition for trophic niches with limited resources, survival, feeding strategies, and metabolic requirements.

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  Short communication 2024-12-18 JECOENV 48:49

  Comparison of the responses of male Japanese treefrog (Dryophytes japonicus) to the rain and advertisement calls

  https://doi.org/10.5141/jee.24.040

  Hahyun Nam , Jin-Kyoung Kim , Jiho Park , Jongsun Kim , Min-Woo Park , Jiyeon Cheon and Daesik Park^*

  [Abstract] Anurans communicate with others using several types of calls such as advertisement, encounter, release, and rain calls. Some treefrog species produce rain calls from their daytime shelters, such as trees and bushes, during both the breeding and non-breeding seasons. However, the function of rain calls is poorly understood. We investigated the potential functions of rain calls by comparing the responses of male Dryophytes japonicus to the playback of advertisement and rain calls. During one minute of playback and three minutes post-playback, the frequencies of orientation and approach of male D. japonicus towards the call-producing speaker did not differ in the rain and advertisement calls. However, the number of individuals, who finally arrived at the speaker among the males, approached towards the speaker, was significantly lower for the rain call compared to the advertisement call during one-minute playback. Our results suggest that both types of calls evoke the attention of conspecific males, but rain calls do not attract conspecific males, unlike advertisement calls. This difference may reflect the distinct functions of rain and advertisement calls.

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  Research 2024-12-12 JECOENV 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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