Influences of biotic and abiotic factors on the relationship between tree productivity and biomass in China

2012 ◽  
Vol 264 ◽  
pp. 72-80 ◽  
Author(s):  
Dafeng Hui ◽  
Jun Wang ◽  
Xuan Le ◽  
Weijun Shen ◽  
Hai Ren
Keyword(s):  
Abiotic Factors ◽  
Biotic And Abiotic Factors ◽  
The Relationship

scholarly journals Assessing Biotic and Abiotic Effects on Biodiversity Index Using Machine Learning

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 461
Author(s):  
Mahmoud Bayat ◽  
Harold Burkhart ◽  
Manouchehr Namiranian ◽  
Seyedeh Kosar Hamidi ◽  
Sahar Heidari ◽  
...  
Keyword(s):  
Machine Learning ◽  
Random Forest ◽  
Forest Ecosystems ◽  
Abiotic Factors ◽  
Basal Area ◽  
Tree Diversity ◽  
Additive Models ◽  
Slope Aspect ◽  
Biotic And Abiotic Factors ◽  
The Relationship

Forest ecosystems play multiple important roles in meeting the habitat needs of different organisms and providing a variety of services to humans. Biodiversity is one of the structural features in dynamic and complex forest ecosystems. One of the most challenging issues in assessing forest ecosystems is understanding the relationship between biodiversity and environmental factors. The aim of this study was to investigate the effect of biotic and abiotic factors on tree diversity of Hyrcanian forests in northern Iran. For this purpose, we analyzed tree diversity in 8 forest sites in different locations from east to west of the Caspian Sea. 15,988 trees were measured in 655 circular permanent sample plots (0.1 ha). A combination of machine learning methods was used for modeling and investigating the relationship between tree diversity and biotic and abiotic factors. Machine learning models included generalized additive models (GAMs), support vector machine (SVM), random forest (RF) and K-nearest–neighbor (KNN). To determine the most important factors related to tree diversity we used from variables such as the average diameter at breast height (DBH) in the plot, basal area in largest trees (BAL), basal area (BA), number of trees per hectare, tree species, slope, aspect and elevation. A comparison of RMSEs, relative RMSEs, and the coefficients of determination of the different methods, showed that the random forest (RF) method resulted in the best models among all those tested. Based on the results of the RF method, elevation, BA and BAL were recognized as the most influential factors defining variation of tree diversity.

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.

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