Floristic and structural changes during old-field succession in the Mexican tropics in relation to site history and species availability

1986 ◽  
Vol 2 (3) ◽  
pp. 257-276 ◽  
Author(s):  
Silvia E. Purata
Keyword(s):  
Structural Changes ◽  
Floristic Composition ◽  
Structural Data ◽  
Structural Development ◽  
Old Field ◽  
Significant Relation ◽  
Forest Environment ◽  
Community Recovery ◽  
Community Patterns ◽  
Composition And Structure

ABSTRACTCommunity patterns along a successional sequence of abandoned fields within a tropical rain forest environment are described in terms of floristic composition and structure. Temporal patterns were summarized and main axes of variation extracted by multivariate methods.External factors – length of cropping period, regrowth age, and proportion of the perimeter occupied by forest communities or remnants (here called forested perimeter) – were related to floristic and structural data on 40 sites. Multivariate direct gradient analysis showed overall floristic development to be positively related to regrowth age and forested perimeter, and negatively related to length of cropping period.Structural development was shown by multiple regression to be positively related to regrowth age and negatively to length of cropping period; but forested perimeter had no significant relation to site structure. The type of crop grown showed no significant relation with floristic or structural development of the regrowth.These results indicate that the conditions of the vegetation around a site have a great effect on community recovery, particularly in its species composition, whilst structure seems to be affected more directly by parameters which imply time.

Composition and community structure of mangroves distributed on the east coast of Marajó Island, Brazil

2022 ◽  
Author(s):  
Barbara Luzia Santos de Oliveira Faro ◽  
Priscila Sanjuan de Medeiros-Sarmento ◽  
Norma Ely Santos Beltrão ◽  
Paulo Weslem Portal Gomes ◽  
Ana Cláudia Caldeira Tavares-Martins
Keyword(s):  
Floristic Composition ◽  
Distribution Patterns ◽  
Major Influence ◽  
Structural Development ◽  
Black Water ◽  
Composition And Structure ◽  
Marine System ◽  
Marajó Island ◽  
White Water ◽  
Degree Of Similarity

Abstract Mangroves in the Amazon are influenced by several environmental conditions that determine the composition and structural development of the arboreal flora, which results in different distribution patterns. In this study, we sought to answer two questions: (1) what is the composition and structure of the mangroves near the mouth of the Amazon River in Marajó Island? (2) Are the fringe and inland mangroves more similar or dissimilar in terms of floristic composition? For this, we delimited a fringe zone and an inland zone about 1 km apart from each other. In each zone, we distributed five 400-m2 plots. The individuals were grouped into diameter and height classes and structural and phytosociological parameters were calculated. Ten species were recorded in the mangroves, of which seven are typical of white-water (várzea) and black-water (igapó) flooded forest ecosystems. We believed the adjacent ecosystems and the hydrological network are inducing the establishment of such species. The composition and structure of mangroves did not differ statistically between zones, and the degree of similarity may be a result of similar environmental factors in these zones such as low relief and high frequency of macrotides. We conclude that the vegetation of the studied mangroves has a major influence of the fluvial-marine system of the great rivers of the Amazon associated with a diversity of ecosystems that, together, generate greater floristic richness when compared to mangroves in other regions.

scholarly journals Plant Diversity Study on Kelekal Protected Forest in Debre Markos Town District, East Gojjam, Amhara Region, Ethiopia

2019 ◽  
Vol 4 (2) ◽  
pp. p98
Author(s):  
Haimanot Reta ◽  
Sebsebe Demissew ◽  
Zemede Asfaw
Keyword(s):  
Cluster Analysis ◽  
Plant Communities ◽  
Hierarchical Cluster Analysis ◽  
Floristic Composition ◽  
Hierarchical Cluster ◽  
Structural Data ◽  
Diversity Indices ◽  
General Distribution ◽  
Line Transect ◽  
Composition And Structure

This research was aimed to investigate floristic composition and structure of Kelekal protected forest established since 1999. For plant data collection, 33 different quadrnts having 400 m2 along seven different line transect were used. The structural data like Frequencies, Density, DBH, Hight, Relative dominance, Relative density and IVI values were calculated for each species and for the selectedwoody plants. The woody plant species having DBH?2.5 cm and height greater than 2.5 m were measured. A hierarchical cluster analysis was performed to classify different plant communities. Shannon winner diversity indices and Sorensen’s similarity indices were used to compare the identified plant communities. Endemic and economically important plants were identified from Flora of Ethiopia and Eritrea books. This research resulted 103 different vascular plants. Eight (7.77%) plants are endemic and the “K” partitioning in the R program using hierarchical cluster analysis resulted three-plant community types. The general distribution pattern of these woody plants at different DBH and height classes showed an inverted Jshape pattern. Four different population patterns were investigated from the density of these species recorded at different DBH class. The result of the structural data provides pertinent information for future forest management techniques in Kelekal protected forest.

scholarly journals Automated computational analysis reveals structural changes in the enteric nervous system of nNOS deficient mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ben R. Cairns ◽  
Benjamin Jevans ◽  
Atchariya Chanpong ◽  
Dale Moulding ◽  
Conor J. McCann
Keyword(s):  
Machine Learning ◽  
Nervous System ◽  
Enteric Nervous System ◽  
Structural Changes ◽  
Computational Analysis ◽  
Confocal Imaging ◽  
Learning Approaches ◽  
Composition And Structure ◽  
Oxide Synthase ◽  
Computational Image Analysis

AbstractNeuronal nitric oxide synthase (nNOS) neurons play a fundamental role in inhibitory neurotransmission, within the enteric nervous system (ENS), and in the establishment of gut motility patterns. Clinically, loss or disruption of nNOS neurons has been shown in a range of enteric neuropathies. However, the effects of nNOS loss on the composition and structure of the ENS remain poorly understood. The aim of this study was to assess the structural and transcriptional consequences of loss of nNOS neurons within the murine ENS. Expression analysis demonstrated compensatory transcriptional upregulation of pan neuronal and inhibitory neuronal subtype targets within the Nos1−/− colon, compared to control C57BL/6J mice. Conventional confocal imaging; combined with novel machine learning approaches, and automated computational analysis, revealed increased interconnectivity within the Nos1−/− ENS, compared to age-matched control mice, with increases in network density, neural projections and neuronal branching. These findings provide the first direct evidence of structural and molecular remodelling of the ENS, upon loss of nNOS signalling. Further, we demonstrate the utility of machine learning approaches, and automated computational image analysis, in revealing previously undetected; yet potentially clinically relevant, changes in ENS structure which could provide improved understanding of pathological mechanisms across a host of enteric neuropathies.

scholarly journals Brown Spiders’ Phospholipases-D with Potential Therapeutic Applications: Functional Assessment of Mutant Isoforms

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 320
Author(s):  
Thaís Pereira da Silva ◽  
Fernando Jacomini de Castro ◽  
Larissa Vuitika ◽  
Nayanne Louise Costacurta Polli ◽  
Bruno César Antunes ◽  
...  
Keyword(s):  
Structural Changes ◽  
Capillary Permeability ◽  
Structural Data ◽  
Histopathological Analysis ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Antigenic Properties ◽  
Harmful Effects

Phospholipases-D (PLDs) found in Loxosceles spiders’ venoms are responsible for the dermonecrosis triggered by envenomation. PLDs can also induce other local and systemic effects, such as massive inflammatory response, edema, and hemolysis. Recombinant PLDs reproduce all of the deleterious effects induced by Loxosceles whole venoms. Herein, wild type and mutant PLDs of two species involved in accidents—L. gaucho and L. laeta—were recombinantly expressed and characterized. The mutations are related to amino acid residues relevant for catalysis (H12-H47), magnesium ion coordination (E32-D34) and binding to phospholipid substrates (Y228 and Y228-Y229-W230). Circular dichroism and structural data demonstrated that the mutant isoforms did not undergo significant structural changes. Immunoassays showed that mutant PLDs exhibit conserved epitopes and kept their antigenic properties despite the mutations. Both in vitro (sphingomyelinase activity and hemolysis) and in vivo (capillary permeability, dermonecrotic activity, and histopathological analysis) assays showed that the PLDs with mutations H12-H47, E32-D34, and Y228-Y229-W230 displayed only residual activities. Results indicate that these mutant toxins are suitable for use as antigens to obtain neutralizing antisera with enhanced properties since they will be based on the most deleterious toxins in the venom and without causing severe harmful effects to the animals in which these sera are produced.

scholarly journals Benthic estuarine communities' contribution to bioturbation under the experimental effect of marine heatwaves

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Dolbeth ◽  
O. Babe ◽  
D. A. Costa ◽  
A. P. Mucha ◽  
P. G. Cardoso ◽  
...  
Keyword(s):  
Community Composition ◽  
Ecosystem Functioning ◽  
Structural Changes ◽  
Nutrient Release ◽  
Biological Communities ◽  
Thermal Change ◽  
Composition And Structure ◽  
Temperature Ranges ◽  
Negative Impacts ◽  
Heat Extremes

AbstractMarine heatwaves are increasing worldwide, with several negative impacts on biological communities and ecosystems. This 24-day study tested heatwaves' effect with distinct duration and recovery periods on benthic estuarine communities' diversity and contribution to ecosystem functioning experimentally. The communities were obtained from a temperate estuary, usually subjected to high daily thermal amplitudes. Our goal was to understand the communities' response to the thermal change, including the community descriptors and behavioural changes expected during heat extremes. We measured community composition and structural changes and the bioturbation process and nutrient release as ecosystem functioning measurements. Overall, our findings highlight the potential tolerance of studied estuarine species to the temperature ranges tested in the study, as community composition and structure were similar, independently of the warming effect. We detected a slight trend for bioturbation and nutrient release increase in the communities under warming, yet these responses were not consistent with the heatwaves exposure duration. Overall, we conclude on the complexity of estuarine communities’ contribution to functioning under warming, and the importance of scalable experiments with benthic organisms' responses to climate variability, accommodating longer time scales and replication. Such an approach would set more efficient expectations towards climate change mitigation or adaptation in temperate estuarine ecosystems.

scholarly journals Urbanization effects on the composition and structure of macrophytes communities in a lotic ecosystem of Pernambuco State, Brazil

2016 ◽  
Vol 76 (4) ◽  
pp. 888-897 ◽  
Author(s):  
L. R. C. C. Xavier ◽  
F. Scherner ◽  
D. C. Burgos ◽  
R. C. Barreto ◽  
S. M. B. Pereira
Keyword(s):  
Urban Areas ◽  
Floristic Composition ◽  
Freshwater Ecosystems ◽  
Metropolitan Region ◽  
Macrophyte Communities ◽  
Composition And Structure ◽  
Lotic Ecosystem ◽  
Dry Seasons ◽  
Urbanized Areas ◽  
Wet And Dry Seasons

Abstract Population growth in urban areas changes freshwater ecosystems, and this can have consequences for macrophyte communities as can be seen in the municipalities that border the Capibaribe River, Pernambuco, Brazil. This study reports the effects of urbanization on the composition and structure of macrophyte communities in areas along that river. The following urbanized and non-urbanized sampling sites were chosen: Sites 1 and 2 (municipality of Santa Cruz do Capibaribe), Sites 3 and 4 (municipality of Toritama), and Sites 5 and 6 (metropolitan region of Recife). These sites were visited every two months from January to July 2013 to observe seasonal variation (wet and dry seasons). Thirty-one species were identified. Generally, the non-urbanized sites had a higher number of species. Multivariate analyses indicated significant overall differences between urbanized and non-urbanized areas (R = 0.044; p < 0.001) and between seasons (R = 0.018; p < 0.019). Owing to the large variation in physical, chemical, and biological characteristics between urbanized and non-urbanized areas, we found that urbanization significantly influenced the floristic composition and structure of macrophyte communities.

scholarly journals Community Arctio-Artemisetum vulgaris (Tx. 1942) Oberd. et al. 1967.: The most widespread ruderal community at Pancevacki rit

2009 ◽  
Vol 24 (2) ◽  
pp. 113-121
Author(s):  
Radmila Stankovic-Kalezic ◽  
Slobodan Jovanovic ◽  
Vaskrsija Janjic ◽  
Ljiljana Radivojevic
Keyword(s):  
Floristic Composition ◽  
Anthropogenic Influences ◽  
Composition And Structure

A several-year investigation of distribution, phytocoenological differentiation, floristic composition and structure of the ruderal flora and vegetation, and relative anthropogenic influences was conducted in the area of Pancevacki rit. The study focused on the ruderal community Arctio-Artemisetum vulgaris, the most widespread of 10 ruderal communities identified in a detailed phytocoenological analysis of the location of Pancevacki rit.

scholarly journals Zebrafish structural development in Mueller-matrix scanning microscopy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aymeric Le Gratiet ◽  
Marta d’Amora ◽  
Marti Duocastella ◽  
Riccardo Marongiu ◽  
Artemi Bendandi ◽  
...  
Keyword(s):  
Structural Changes ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Mueller Matrix ◽  
Fluorescence Probes ◽  
Imaging Method ◽  
Structural Development ◽  
Matrix Formalism ◽  
Label Free ◽  
Biological Organization

AbstractZebrafish are powerful animal models for understanding biological processes and the molecular mechanisms involved in different human diseases. Advanced optical techniques based on fluorescence microscopy have become the main imaging method to characterize the development of these organisms at the microscopic level. However, the need for fluorescence probes and the consequent high light doses required to excite fluorophores can affect the biological process under observation including modification of metabolic function or phototoxicity. Here, without using any labels, we propose an implementation of a Mueller-matrix polarimeter into a commercial optical scanning microscope to characterize the polarimetric transformation of zebrafish preserved at different embryonic developmental stages. By combining the full polarimetric measurements with statistical analysis of the Lu and Chipman mathematical decomposition, we demonstrate that it is possible to quantify the structural changes of the biological organization of fixed zebrafish embryos and larvae at the cellular scale. This convenient implementation, with low light intensity requirement and cheap price, coupled with the quantitative nature of Mueller-matrix formalism, can pave the way for a better understanding of developmental biology, in which label-free techniques become a standard tool to study organisms.

Шумпетерова теорија економска раста: Предузетништво као одговор на економску стагнацију // Schumpeterian growth theory: Entrepreneurship - a response to the economic downturn

2013 ◽  
Vol 11 (18) ◽  
pp. 219
Author(s):  
Јово Атељевић
Keyword(s):  
Structural Changes ◽  
Marxist Theory ◽  
Growth Theory ◽  
Economic Downturn ◽  
Structural Development ◽  
Economic Cycles ◽  
Relevant Today ◽  
Perfect Model ◽  
Anglo American ◽  
Schumpeterian Growth Theory

Резиме: Игнорисање и неразумијевање Шумпетеровог писања су главни разлози зашто је британско-америчка школа, као доминантна у контексту неокласичне економије, била и још увијек јесте одвојена од њемачке историјске школе. Међутим, Шумпетерове поставке су и данас релевантне будући да систем опште економске равнотеже нема праву теорију ендогеног или структуралног развоја коју је предложио Шумпетер. Његова теорија економског развоја може послужити као кохерентни одговор на марксистичку теорију. За Шумпетера, унутаркапиталистичка конкуренција у потпуности објашњава структурне промјене у економији. Он тврди да је конкуренција динамички процес разлика и борбе међу компанијама, а не статична конкуренција Валрасовог система. У Шумпетеровој властитој визији економског система, теорија економских циклуса и теорија раста су нераздвојне. Циљ овог рада је да кроз синтезу теоретских анализа потврди релевантност Шумпетерове теорије у контексту дигиталне економије.Summary: Ignorance and misunderstanding of Schumpeter’s writing are the main reasons why the Anglo-American School, as dominant in the context of neoclassical economics, was and still is separate from the German Historical School. However, Schumpeter’s arguments are relevant today because the system of general economic equilibrium has no adequate theory able to explain neither endogenous nor structural development proposed by Schumpeter. His theory of economic development can serve as a coherent response to Marxist theory. For Schumpeter, the intra-capitalist competition fully explains the structural changes in the economy. He argues that competition is a dynamic process of differences and struggles between companies, and not static competition as proposed by the Walrasian mathematical perfect model. Schumpeter argues that the theory of economic cycles and the growth theory are inseparable. The overarching aim of this paper is to through synthesize of theoretical analysis confirms the relevance of Schumpeter’s theory in the context of the digital economy.

DIVERSITAS FLORISTIK DAN STRUKTUR VEGETASI DI HUTAN GUNUNG PAYUNG, TAMAN NASIONAL UJUNG KULON

2018 ◽  
Vol 17 (3) ◽  
Author(s):  
Purwaningsih Purwaningsih ◽  
Tika D. Atikah
Keyword(s):  
Forest Structure ◽  
National Park ◽  
Floristic Composition ◽  
Forest Stand ◽  
Floristic Diversity ◽  
Lagerstroemia Speciosa ◽  
Large Numbers ◽  
Composition And Structure ◽  
Quadrat Method ◽  
Artocarpus Elasticus

A floristic diversity and vegetation forest structure was carried out on the Mount Payung, Ujung Kulon National Park. The objective was to floristic composition and structure of the forest located at the peninsula of Ujung Kulon, Banten. The study was conducted using the quadrat method by establishing plots of 5000 m2 each at two locations Pasir Ipis and Gunung Keneng, thus the total area sampled was 1 ha. They were Plot Pasir Ipis and Plot Gunung Keneng. A total of 1898 trees comprising 105 species of 74 genera and 43 families were recorded. The number of species at Pasir Ipis higher (90 species) than plot Gn Keneng (61 species). Based on calculation the important value indexes (IVI), there were some dominan species with IVI >10 at Pasir Ipis Neesia altissima (IV=21,55), Barringtonia racemosa (17,89), Payena acuminata (13,35) and Neonauclea lanceolata (12,37). The dominated species at Plot Gn Kendeng were Pseuduvaria reticulata (IV= 34,30), Dillenia excelsa (27,62), Lagerstroemia speciosa (20,89), Popowia pisocarpa (17,57). The structure of forest could be inferred from the diameter and height of trees. The diameter measurements showed that 75,57 % of trees in plot Pasir Ipis and 80,51 % in plot Gunung Kendeng consist of small individuals with diameters between 10-20 cm. Trees with large diameters of >100 cm occurred in two plots among them Barringtonia racemosa, Polyalthia lateriflora, Popowia pisocarpa, Artocarpus elasticus. The presence of large numbers of small trees and lesser numbers of trees with large diameters in a forest stand indicated that the stand was regenerating after heavy disturbance. The presence of the majority of trees with height of < 20 m (99 %) further confirmed the forest’s dynamic status.

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