scholarly journals Tree stand mortality in nationally important park-monument of landscape art Feofaniya

2021 ◽  
Author(s):  
R. O. Feschenko ◽  
◽  
R. K. Matyashuk ◽  
A. M. Bilous ◽  
◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Urban Ecosystems ◽  
Formation Condition ◽  
Forest Stands ◽  
Tree Stand ◽  
Local Formation ◽  
Aboveground Phytomass ◽  
Landscape Art ◽  
Biotic And Abiotic Factors ◽  
Dead Trees

Tree stand mortality in urban ecosystems indicates the influence level of biotic and abiotic factors primarily on their life state. The significance of these processes lies in the knowledge of the forest stands patterns development and their use for forecasting and assessing ecosystem services. The territories of the nature reserve fund have been taken as research sites, as significant indicators of anthropogenically altered territories. The structure of biomass and forest stands species composition was found to be associated with the growth and development of living trees and the formation of dead trees. Biotic and abiotic factors, intraspecific competition and peculiarities of local formation condition and stands growth are determined to affect the life state of the main forest-forming species directly and indirectly. It was revealed that in the medieval oak plantation, the loss of trees during the research period (2016-2020) prevailed over the increase in the stand ground phytomass. It was found that the carbon deposited amount in the forest stands aboveground phytomass reflects the unusual dynamics for the overwhelming number of territory indicators. The litter formation caused the changes in the deposited carbon structure of the research stands phytomass by tree species. It also led to an increase in the deadwood carbon pool and the onset of carbon emissions from the detritus decomposition.

scholarly journals Flow cytometric measurements as a proxy for sporulation intensity in the cultured macroalga Ulva (Chlorophyta)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Omri Nahor ◽  
Cristina F. Morales-Reyes ◽  
Gianmaria Califano ◽  
Thomas Wichard ◽  
Alexander Golberg ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Life Cycle ◽  
Abiotic Factors ◽  
Physiological Status ◽  
Seaweed Cultivation ◽  
Reproductive Growth ◽  
Biotic And Abiotic Factors ◽  
Flow Cytometric ◽  
Abiotic Stimuli ◽  
Fundamental Shift

Abstract Controlling the life cycle of the green macroalga Ulva (Chlorophyta) is essential to maintain its efficient aquaculture. A fundamental shift in cultivation occurs by transforming the thallus cells into gametangia and sporangia (sporulation), with the subsequent release of gametes and zoids. Sporulation occurrence depends on algal age and abiotic stimuli and is controlled by sporulation inhibitors. Thus, quantification of sporulation intensity is critical for identifying the biotic and abiotic factors that influence the transition to reproductive growth. Here, we propose to determine the sporulation index by measuring the number of released gametes using flow cytometry, in proportion to the total number of thallus cells present before the occurrence of the sporulation event. The flow cytometric measurements were validated by manually counting the number of released gametes. We observed a variation in the autofluorescence levels of the gametes which were released from the gametangia. High autofluorescence level correlated to phototactically active behaviour of the gametes. As autofluorescence levels varied between different groups of gametes related to their mobility, flow cytometry can also determine the physiological status of the gametes used as feedstock in seaweed cultivation.

scholarly journals Spatial distribution and survival rate of waterfrog tadpoles in relation to biotic and abiotic factors: a field experiment

2001 ◽  
Vol 22 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Sylvie Thurnheer ◽  
Heinz-Ulrich Reyer
Keyword(s):  
Spatial Distribution ◽  
Community Dynamics ◽  
Abiotic Factors ◽  
Rana Esculenta ◽  
Natural Conditions ◽  
Major Purpose ◽  
Biotic And Abiotic Factors ◽  
Lab Experiments ◽  
Shallow Zone ◽  
Population And Community Dynamics

AbstractPredictions about population and community dynamics are usually based on lab experiments. Because the results are difficult to transfer to natural conditions, the major purpose of this study was to test the effects of biotic and abiotic factors on tadpole populations in a natural environment. We stocked six ponds, created the previous year, with known numbers of Rana esculenta and R. lessonae tadpoles and followed their development over several months. When compared among ponds, tadpole density correlated positively with the nitrate:phosphate ratio. This suggests that water chemistry may have affected survival, either directly or indirectly via productivity. Within ponds, both species showed a clear preference for the shallow zone. This behavior probably reflects a preference for warm water close to the surface, rather than avoidance of predators, because relative densities of odonates also increased from deep to shallow zones. This study is one of few that not only considers the distribution of the anuran tadpoles but the distribution of their predators as well.

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