scholarly journals Distribution Patterns of Odonate Assemblages in Relation to Environmental Variables in Streams of South Korea

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 152 ◽  
Author(s):  
Da-Yeong Lee ◽  
Dae-Seong Lee ◽  
Mi-Jung Bae ◽  
Soon-Jin Hwang ◽  
Seong-Yu Noh ◽  
...  

Odonata species are sensitive to environmental changes, particularly those caused by humans, and provide valuable ecosystem services as intermediate predators in food webs. We aimed: (i) to investigate the distribution patterns of Odonata in streams on a nationwide scale across South Korea; (ii) to evaluate the relationships between the distribution patterns of odonates and their environmental conditions; and (iii) to identify indicator species and the most significant environmental factors affecting their distributions. Samples were collected from 965 sampling sites in streams across South Korea. We also measured 34 environmental variables grouped into six categories: geography, meteorology, land use, substrate composition, hydrology, and physicochemistry. A total of 83 taxa belonging to 10 families of Odonata were recorded in the dataset. Among them, eight species displayed high abundances and incidences. Self-organizing map (SOM) classified sampling sites into seven clusters (A–G) which could be divided into two distinct groups (A–C and D–G) according to the similarities of their odonate assemblages. Clusters A–C were characterized by members of the suborder Anisoptera, whereas clusters D–G were characterized by the suborder Zygoptera. Non-metric multidimensional scaling (NMDS) identified forest (%), altitude, and cobble (%) in substrata as the most influential environmental factors determining odonate assemblage compositions. Our results emphasize the importance of habitat heterogeneity by demonstrating its effect on odonate assemblages.

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Leonardo Antunes Pessoa ◽  
Matheus Tenório Baumgartner ◽  
Marcelo Percilio Santana Junior ◽  
João Paulo Alves Pagotto ◽  
Luiz Gustavo Antunes Pessoa ◽  
...  

Abstract The use and occupation of land by human population substantially influence environmental variables and fish assemblage in streams. However, there is little knowledge on how these changes affect the ecomorphological structure of fish assemblage in mesohabitats. Therefore, we aim to assess whether the land-use types affect the ecomorphological structure of fish assemblage in distinct mesohabitats. Environmental and ichthyofaunistic data were collected in three mesohabitats (rifles, runs, and pools) of five rural and five urban streams. Twenty-one ecomorphological indices were obtained from the mean of linear morphological measurements and areas of the fishes. Subsequently, the Euclidean distance was calculated, based on the ecomorphological indices, between each pair of species, to measure the ecomorphological distances for the mesohabitats of the rural and urban streams. The results show that the urban environment is more harmful to streams than the rural one, due to changes in the environmental variables and decrease in species richness. The main environmental changes found in urban streams were the decrease in canopy cover by riparian vegetation and dissolved oxygen, and the increase in electrical conductivity and bed silting. Also, there was a significant decrease in the morphological similarity between fish species in the mesohabitats of urban streams compared to rural ones. Therefore, we can conclude that the urban environment leads to the loss of morphologically similar fish species in the mesohabitats, with only a few functionally distinct species remaining.


Diversity ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 186
Author(s):  
Khishigdelger Enkhtur ◽  
Bazartseren Boldgiv ◽  
Martin Pfeiffer

Geometrids are a species-rich group of moths that serve as reliable indicators for environmental changes. Little is known about the Mongolian moth fauna, and there is no comprehensive review of species richness, diversity, and distribution patterns of geometrid moths in the country. Our study aims to review the existing knowledge on geometrid moths in Mongolia. We compiled geometrid moth records from published scientific papers, our own research, and from the Global Biodiversity Information Facility (GBIF) to produce a checklist of geometrid moths of Mongolia. Additionally, we analyzed spatial patterns, species richness, and diversity of geometrid moths within 14 ecoregions of Mongolia and evaluated environmental variables for their distribution. In total, we compiled 1973-point records of 388 geometrid species. The most species-rich ecoregion in Mongolia was Daurian Forest Steppe with 142 species. Annual precipitation and maximum temperature of the warmest month were the most important environmental variables that correlated with NMDS axes in an analysis of geometrid assemblages of different ecoregions in Mongolia.


2020 ◽  
Vol 4 (1) ◽  
pp. 31
Author(s):  
Nur Lathifah Syakbanah

Land use is an important environmental factor in the dynamics of human health. In the case of leptospirosis, environmental transmission cycles are caused by rat transition, environmental changes and populations at risk. Utilization of GIS-based spatial analysis may help detecting distribution patterns of leptospirosis cases, allocating resources and planning effective control and surveillance programs in endemic areas. This study aims to analyze the spatial distribution of leptospirosis based on land use and stream flow in Bantul District, 2010-2018. This ecological study was conducted in Bantul District, Yogyakarta for 9 years. Spatial analysis overlays processed data on leptospirosis cases per village and land use maps of 2016 using QGIS 3.0. Spatial distribution of 12 of high leptospirosis villages (18-35 cases) are in residential areas, tributaries, croplands, irrigated fields, rain-fed rice fields, and plantations. Those villages was crossed by major river basin which is potentially as transmission media of leptospirosis cases after heavy rainfall. It is suggested to increase the Early Awareness and Alert (EAA) system by active surveillance of early case finding from the government and endemic villagers.


PeerJ ◽  
2019 ◽  
Vol 6 ◽  
pp. e6234
Author(s):  
Tomonari Okada ◽  
Yugo Mito ◽  
Erina Iseri ◽  
Toshiyuki Takahashi ◽  
Takanori Sugano ◽  
...  

Wetlands, tidal flats, seaweed beds, and coral reefs are valuable not only as habitats for many species, but also as places where people interact with the sea. Unfortunately, these areas have declined in recent years, so environmental improvement projects to conserve and restore them are being carried out across the world. In this study, we propose a method for quantifying ecosystem services, that is, useful for the proper maintenance and management of artificial tidal flats, a type of environmental improvement project. With this method, a conceptual model of the relationship between each service and related environmental factors in natural and social systems was created, and the relationships between services and environmental factors were clarified. The state of the environmental factors affecting each service was quantified, and the state of those factors was reflected in the evaluation value of the service. As a result, the method can identify which environmental factors need to be improved and if the goal is to increase the value of the targeted tidal flat. The method demonstrates an effective approach in environmental conservation for the restoration and preservation of coastal areas.


2019 ◽  
Vol 14 (2) ◽  
pp. 257-274
Author(s):  
Romina Paola Nievas ◽  
Mirian Roxana Calderon ◽  
Marta Matilde Moglia

Urbanization is one of the main causes driving changes in biodiversity patterns and it is regarded as a major threat to native biota. Successful exotic plant invasion depends on invasiveness and invasibility. Invasiveness is related to the characteristics of exotic plants and invasibility to the features of the sites. The objective of this study was to identify the invasibility environmental factors affecting the success of exotic plant invasion in a wildland-urban ecotone of the central region of Argentina (Potrero de los Funes Village, San Luis). Fifty phytosociological inventories were recorded in an area of 700 ha during spring and summer seasons (2013–2015). Abundance-coverage values of plants and environmental variables such as soil characteristics, anthropogenic disturbance, and altitude of the sites were assessed. Soil moisture, electrical conductivity (EC), acidity (pH), organic matter content, and nitrates were determined as part of the soil analysis. A Nonmetric Multidimensional Scaling analysis was used to identify the possible relationship between abundance-coverage of the vegetation and environmental variables. Abundance-coverage of exotic plants was positively influenced by anthropogenic disturbance and nitrate levels, and negatively affected by altitude. However, no significant correlation was found between percentage of exotic plants and pH, EC, or soil moisture. Thus, urbanization and touristic activities influenced the success of exotic plant invasion.


Polar Biology ◽  
2020 ◽  
Vol 43 (11) ◽  
pp. 1693-1705
Author(s):  
Miriam L. S. Hansen ◽  
Dieter Piepenburg ◽  
Dmitrii Pantiukhin ◽  
Casper Kraan

Abstract In times of accelerating climate change, species are challenged to respond to rapidly shifting environmental settings. Yet, faunal distribution and composition are still scarcely known for remote and little explored seas, where observations are limited in number and mostly refer to local scales. Here, we present the first comprehensive study on Eurasian-Arctic macrobenthos that aims to unravel the relative influence of distinct spatial scales and environmental factors in determining their large-scale distribution and composition patterns. To consider the spatial structure of benthic distribution patterns in response to environmental forcing, we applied Moran’s eigenvector mapping (MEM) on a large dataset of 341 samples from the Barents, Kara and Laptev Seas taken between 1991 and 2014, with a total of 403 macrobenthic taxa (species or genera) that were present in ≥ 10 samples. MEM analysis revealed three spatial scales describing patterns within or beyond single seas (broad: ≥ 400 km, meso: 100–400 km, and small: ≤ 100 km). Each scale is associated with a characteristic benthic fauna and environmental drivers (broad: apparent oxygen utilization and phosphate, meso: distance-to-shoreline and temperature, small: organic carbon flux and distance-to-shoreline). Our results suggest that different environmental factors determine the variation of Eurasian-Arctic benthic community composition within the spatial scales considered and highlight the importance of considering the diverse spatial structure of species communities in marine ecosystems. This multiple-scale approach facilitates an enhanced understanding of the impact of climate-driven environmental changes that is necessary for developing appropriate management strategies for the conservation and sustainable utilization of Arctic marine systems.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6733 ◽  
Author(s):  
Yangchun Gao ◽  
Yiyong Chen ◽  
Wei Xiong ◽  
Shiguo Li ◽  
Aibin Zhan

Background Dinoflagellates have the potential to pose severe ecological and economic damages to aquatic ecosystems. It is therefore largely needed to understand the causes and consequences of distribution patterns of dinoflagellate communities in order to manage potential environmental problems. However, a majority of studies have focused on marine ecosystems, while the geographical distribution patterns of dinoflagellate communities and associated determinants in freshwater ecosystems remain unexplored, particularly in running water ecosystems such as rivers and streams. Methods Here we utilized multiple linear regression analysis and combined information on species composition recovered by high-throughput sequencing and spatial and environmental variables to analyze the distribution patterns of dinoflagellate communities along the Songhua River. Results After high-throughput sequencing, a total of 490 operational taxonomic units (OTUs) were assigned to dinoflagellates, covering seven orders, 13 families and 22 genera. Although the sample sites were grouped into three distinctive clusters with significant difference (p < 0.05) in environmental variables, OTUs-based dinoflagellate communities among the three clusters showed no significant difference (p > 0.05). Among all 24 environmental factors, two environmental variables, including NO3-N and total dissolved solids (TDS), were selected as the significantly influential factors (p < 0.05) on the distribution patterns of dinoflagellate communities based on forward selection. The redundancy analysis (RDA) model showed that only a small proportion of community variation (6.1%) could be explained by both environmental (NO3-N and TDS) and dispersal predictors (watercourse distance) along the River. Variance partitioning revealed a larger contribution of local environmental factors (5.85%) than dispersal (0.50%) to the total variation of dinoflagellate communities. Discussion Our findings indicated that in addition to the two quantifiable processes in this study (species sorting and dispersal), more unquantifiable stochastic processes such as temporal extinction and colonization events due to rainfall may be responsible for the observed geographical distribution of the dinoflagellate community along the Songhua River. Results obtained in this study suggested that deeper investigations covering different seasons are needed to understand the causes and consequences of geographical distribution patterns of dinoflagellate biodiversity in river ecosystems.


2006 ◽  
Vol 52 (3) ◽  
pp. 188-195 ◽  
Author(s):  
J. M. Vargas ◽  
J. C. Guerrero ◽  
M. A. Farfán ◽  
A. M. Barbosa ◽  
R. Real

2017 ◽  
Vol 68 (10) ◽  
pp. 1877 ◽  
Author(s):  
Wang Tian ◽  
Huayong Zhang ◽  
Lei Zhao ◽  
Hai Huang

Phytoplankton is the primary producer and the basis of most aquatic food webs. Characterising the variations in phytoplankton communities and the factors affecting these variations in a fluctuating environment are central issues in ecology and essential to developing appropriate conservation strategies. In the present study, seasonal variations in the phytoplankton community and the driving environmental factors were analysed based on data from Lake Nansihu in 2013. In all, 138 phytoplankton species were identified. The phytoplankton community exhibited seasonal variations, with a mean abundance that ranged from 5.00×105 cells L–1 in winter to 4.57×106 cells L–1 in summer and a mean biomass that varied from 0.44mgL–1 in winter to 3.75mgL–1 in summer. A spring algal bloom did not appear in this warm, temperate monsoon lake, but an algal bloom did appear in summer when the temperature and nutrient concentrations were high. There were substantial seasonal variations in the dominant phytoplankton taxa, from Chlorophyta, Bacillariophyta and Euglenophyta in spring to Chlorophyta and Bacillariophyta in summer, followed by dominance of Chlorophyta in autumn and Bacillariophyta in winter. Results of canonical correspondence analysis indicated that although the environmental factors affecting the seasonal variations in different phytoplankton species varied, water temperature, total nitrogen, total phosphorus and ammonia nitrogen appeared to be the most dominant. These four variables were also the main environmental factors driving the seasonal variations in the phytoplankton community in the lake. The results of the present study will be useful in guaranteeing the water quality and ecological security of Lake Nansihu.


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