scholarly journals Seasonal Changes in Pinus tabuliformis Root-Associated Fungal Microbiota Drive N and P Cycling in Terrestrial Ecosystem

2021 ◽  
Vol 11 ◽  
Author(s):  
Hai-Hua Wang ◽  
Hong-Long Chu ◽  
Qing Dou ◽  
Huan Feng ◽  
Ming Tang ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Seasonal Changes ◽  
Environmental Changes ◽  
Enzymatic Activities ◽  
Colonization Rate ◽  
Fungal Colonization ◽  
Mycorrhizal Roots ◽  
Edaphic Properties ◽  
Fungal Microbiota ◽  
N And P Cycling

In terrestrial ecosystems, mycorrhizal roots play a key role in the cycling of soil carbon (C) and other nutrients. The impact of environmental factors on the mycorrhizal fungal community has been well studied; however, the seasonal variations in the root-associated fungal microbiota affected by environmental changes are less clear. To improve the understanding of how environmental factors shape the fungal microbiota in mycorrhizal roots, seasonal changes in Pinus tabuliformis root-associated fungi were investigated. In the present study, the seasonal dynamics of edaphic properties, soil enzymatic activities, root fungal colonization rates, and root-associated fungal microbiota in P. tabuliformis forests were studied across four seasons during a whole year to reveal their correlations with environmental changes. The results indicate that the soil functions, such as the enzymatic activities related to nitrogen (N) and phosphorus (P) degradation, were varied with the seasonal changes in microclimate factors, resulting in a significant fluctuation of edaphic properties. In addition, the ectomycorrhizal fungal colonization rate in the host pine tree roots increased during warm seasons (summer and autumn), while the fungal colonization rate of dark septate endophyte was declined. Moreover, the present study indicates that the fungal biomass increased in both the pine roots and rhizospheric soils during warm seasons, while the fungal species richness and diversity decreased. While the Basidiomycota and Ascomycota were the two dominant phyla in both root and soil fungal communities, the higher relative abundance of Basidiomycota taxa presented in warm seasons. In addition, the fungal microbial network complexity declined under the higher temperature and humidity conditions. The present study illustrates that the varieties in connectivity between the microbial networks and in functional taxa of root-associated fungal microbiota significantly influence the soil ecosystem functions, especially the N and P cycling.

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 ◽  
...  
Keyword(s):  
Land Use ◽  
Ecosystem Services ◽  
Environmental Factors ◽  
South Korea ◽  
Habitat Heterogeneity ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Distribution Patterns ◽  
Self Organizing Map ◽  
Factors Affecting

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.

scholarly journals Graptolite dynamics in Silurian and Devonian time

1987 ◽  
Vol 35 ◽  
pp. 149-159
Author(s):  
T. N. Koren'
Keyword(s):  
Environmental Factors ◽  
Sea Level ◽  
Comparative Studies ◽  
Climate Changes ◽  
Environmental Changes ◽  
Time Intervals ◽  
Early Devonian ◽  
Carbonate Sedimentation ◽  
Reference Sections ◽  
Devonian Age

On the basis of biostratigraphic data known at present some preliminary attempts are made to evaluate graptolite dynamics, that is changes in graptolite diversity in time and space within pelagic fades of Si­lurian and Early Devonian age. For the comparative studies of diversity fluctuations versus some major environmental changes a standard graptolite zonation is used. Several critical and more or less well stu­died stratigraphical intervals are chosen; among them the Ordovician/Silurian, Sheinwoodian/Gorstian and Gorstian/Ludfordian boundary beds. For each level the most complete reference sections are analy­zed. Special attention is given to the graptolite extinction, specification and radiation events within these time intervals. They might have been partly connected with or influenced by the environmental factors as a result of eustatic sea-level and climate changes, alteration of anoxic conditions, migration of carbonate sedimentation in pelagic direction, and other globally detectable events. The graptolite evolution during the time of monograptid existence can be subdivided into three phases using the comparison of the ampli­tude of the extinction-origination events and repeatability of the synphasic cycles.

Environmental Concerns and International Migration

1996 ◽  
Vol 30 (1) ◽  
pp. 105-131 ◽  
Author(s):  
Graeme Hugo
Keyword(s):  
Environmental Factors ◽  
International Migration ◽  
Environmental Changes ◽  
Environmental Concerns ◽  
Independent Variable

This article focuses on international migration occurring as a result of environmental changes and processes. It briefly reviews attempts to conceptualize environment-related migration and then considers the extent to which environmental factors have been and may be significant in initiating migration. Following is an examination of migration as an independent variable in the migration-environment relationship. Finally, ethical and policy dimensions are addressed.

scholarly journals Key Environmental Factors Controlling Planktonic Foraminiferal and Pteropod Community’s Response to Late Quaternary Hydroclimate Changes in the South Aegean Sea (Eastern Mediterranean)

2020 ◽  
Vol 8 (9) ◽  
pp. 709
Author(s):  
Christina Giamali ◽  
George Kontakiotis ◽  
Efterpi Koskeridou ◽  
Chryssanthi Ioakim ◽  
Assimina Antonarakou
Keyword(s):  
Environmental Factors ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Planktonic Foraminifera ◽  
Explanatory Power ◽  
Principal Component ◽  
Aegean Sea ◽  
Late Glacial ◽  
The South

A multidisciplinary study was conducted in order to investigate the environmental factors affecting the planktonic foraminiferal and pteropod communities of the south Aegean Sea. Aspects of the Late Quaternary paleoceanographic evolution were revealed by means of quantitative analyses of planktonic foraminiferal and pteropod assemblages (including multivariate statistical approach; principal component analysis (PCA)), the oxygen (δ18O) and carbon (δ13C) isotopic composition of planktonic foraminifera and related paleoceanographic (planktonic paleoclimatic curve (PPC), productivity (E-index), stratification (S-index), seasonality) indices, extracted by the gravity core KIM-2A derived from the submarine area between Kimolos and Sifnos islands. Focusing on the last ~21 calibrated thousands of years before present (ka BP), cold and eutrophicated conditions were identified during the Late Glacial period (21.1–15.7 ka BP) and were followed by warmer and wetter conditions during the deglaciation phase. The beginning of the Holocene was marked by a climatic amelioration and increased seasonality. The more pronounced environmental changes were identified during the deposition of the sapropel sublayers S1a (9.4–7.7 ka BP) and S1b (6.9–6.4 ka BP), with extremely warm and stratified conditions. Pteropod fauna during the sapropel deposition were recorded for the first time in the south Aegean Sea, suggesting arid conditions towards the end of S1a. Besides sea surface temperature (SST), which shows the highest explanatory power for the distribution of the analyzed fauna, water column stratification, primary productivity, and seasonality also control their communities during the Late Quaternary.

Seasonal changes in louse populations on white-tailed deer (Odocoileus virginianus)

1975 ◽  
Vol 53 (8) ◽  
pp. 1047-1054 ◽  
Author(s):  
Thomas G. Watson ◽  
Roy C. Anderson
Keyword(s):  
Environmental Factors ◽  
Solar Radiation ◽  
Head And Neck ◽  
Odocoileus Virginianus ◽  
Seasonal Changes ◽  
Radiation Temperature ◽  
Upper Body ◽  
Immature Stages ◽  
Body Regions ◽  
Biting Lice

The hides of 47 white-tailed deer (Odocoileus virginianus) shot at Long Point, Ontario, between September 1972 and August 1973 were examined for lice. Adult Tricholipeurus lipeuroides were most abundant from January to April and T. parallelus from May to August. The distributions of biting lice changed over the study period, possibly influenced by environmental factors such as solar radiation, temperature, rainfall, and changes in pelage. Solenopotes ferrisi was found throughout the study period. There was no significant change in abundance of the various louse stages throughout the study, although all stages were slightly more numerous during winter. Adults primarily infested the head and neck, while immature stages infested upper body regions. Changes in distribution of lice may be the result of environmental and host pelage changes.

Seasonal changes in mycorrhizal and fibrous-textured root biomass in 23- and 180-year-old Pacific silver fir stands in western Washington

1980 ◽  
Vol 10 (4) ◽  
pp. 523-529 ◽  
Author(s):  
Kristiina A. Vogt ◽  
Robert L. Edmonds ◽  
Charles C. Grier ◽  
Stephen R. Piper
Keyword(s):  
Seasonal Changes ◽  
Root Biomass ◽  
Fine Root Biomass ◽  
Early Summer ◽  
Silver Fir ◽  
Fibrous Root ◽  
Mycorrhizal Root ◽  
Young Stand ◽  
Soil Temperatures ◽  
Mycorrhizal Roots

Seasonal changes in mycorrhizal and fibrous root biomass were examined in 23- and 180-year-old Abiesamabilis (Dougl.) Forbes stands. Both stands had similar patterns of change in mycorrhizal root biomass with the lowest level in the summer and highest in the fall. The fall peak of fine root biomass was the result of increased mycorrhizal and not fibrous root biomass. High levels of active mycorrhizal root biomass were measured during the winter months under a snowpack at soil temperatures of 1 °C. In both stands mycorrhizal roots comprised the largest proportion of the weight of fine roots during the winter (29%) and the lowest during the summer (2%). Except during early summer, the old stand had significantly higher levels of mycorrhizal root biomass in comparison to the young stand throughout the year.

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