scholarly journals Population structure of Fagus grandifolia subsp. mexicana in the cloud forest of Hidalgo State, Mexico

2016 ◽  
Vol 94 (3) ◽  
pp. 483 ◽  
Author(s):  
Adriana Beatriz Ortiz-Quijano ◽  
Arturo Sánchez-González ◽  
Lauro López-Mata ◽  
José Villanueva-Díaz
Keyword(s):  
Population Structure ◽  
Community Structure ◽  
Environmental Conditions ◽  
Cloud Forest ◽  
Basal Area ◽  
Fagus Grandifolia ◽  
Species Level ◽  
Anthropogenic Activity ◽  
Recent Past ◽  
Beech Forests

The highest densities and largest areas of <em>Fagus grandifolia</em> subsp. <em>mexicana</em> in Mexico grow in the cloud forest of the state of Hidalgo. Although this taxon is endangered, there is little information about its population structure. This study provides data on the structure of heights, diameters and ages of <em>Fagus</em> in three populations in Hidalgo. Additionally, information was obtained on the structure of the beech forests, whose canopy is dominated by <em>Fagus</em>. At each locality, three to five 400 m<sup>2</sup> sample plots, depending on the size of the respective forest, were randomly selected. Within each plot, density and basal area of each species of tree and shrub with diameter greater than 2.5 cm (1.30 m) were estimated. At the species level, populations are dynamic, with a high percentage of young individuals; however, at one of the localities, changes have occurred in the last decade due to anthropogenic activity, and the structure of sizes and diameters in the youngest age categories has changed. Diameter was a good indicator of the age of the trees. At the community level, the dominance of <em>Fagus</em> and other species differed between localities, which is probably related to the degree of disturbance. Population and community structure are related and could be considered as indicators of changes in environmental conditions in the recent past and today.

scholarly journals Current Status and Recent Stand Structure Dynamics in Mixed Silver Fir—European Beech Forests in Croatian Dinarides: Are There Differences between Managed and Unmanaged Forests?

2021 ◽  
Vol 13 (16) ◽  
pp. 9179
Author(s):  
Jura Čavlović ◽  
Marijana Andabaka ◽  
Mario Božić ◽  
Krunoslav Teslak ◽  
Karlo Beljan
Keyword(s):  
Basal Area ◽  
Forest Monitoring ◽  
Current Status ◽  
Stand Dynamics ◽  
Silver Fir ◽  
Recent Past ◽  
Beech Forests ◽  
Private Forests ◽  
Large Trees ◽  
Crown Defoliation

The environmental, social and economic potential of Dinaric uneven-aged forests along with the complex stand dynamics influenced by different long-term management approaches and environmental factors require comprehensive forest monitoring. This study aimed to explore differences in the current status and recent past dynamics of stand structures between unmanaged and managed mixed fir-beech forests in the Croatian part of the Dinaric Alps using large-scale data from an established monitoring system. From the 74 permanent sample plots distributed within the forest type measured in 2008 and re-measured in 2019, we stratified four strata (types of management regimes): (1) forests out of regular management and tree harvest for at least 30 years, (2) managed state forests on carbonate bedrock, (3) managed state forests on non-carbonate bedrock and (4) managed private forests. In each sample plot, 34 structural attributes were computed to assess indicators of their current status and recent past dynamics of stands in the studied forests. An increasing Q shape diameter distribution with a high number of large and very large trees characterize unmanaged forests and managed forests on non-carbonate bedrock. In managed state forests and private forests, variable (rotated sigmoid) and constant (negative exponential) results were obtained, respectively. Principal component analysis (PCA) distinguished managed and unmanaged forests with decreasing harvest volume and recruitment, increasing basal area, number of very large trees, average diameter at breast height (DBH), crown defoliation of firs and basal area of died beech trees. The current structure, recent and expected stand dynamics in the unmanaged forests (accumulation of standing volume, increase of large diameter trees and large snags, large share of beech, large mean DBH) can be recognized as old-growth attributes. The differences between the studied forest types, potential of both unmanaged and state managed fir-beech forests and approaches to sustain multifunctional forest management in the Dinaric region were discussed.

Dissolved oxygen and temperature best predict deep-sea fish community structure in the Gulf of California with climate change implications

2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Community Composition ◽  
Environmental Conditions ◽  
Deep Sea ◽  
Gulf Of California ◽  
Fish Community ◽  
Demersal Fish ◽  
Fish Community Structure ◽  
Explained Variance

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.

scholarly journals Morphological Variations of Wild Populations of Brycon dentex (Characidae, Teleostei) in the Guayas Hydrographic Basin (Ecuador). The Impact of Fishing Policies and Environmental Conditions

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1901
Author(s):  
Ana Gonzalez-Martinez ◽  
Carmen De-Pablos-Heredero ◽  
Martin González ◽  
Jorge Rodriguez ◽  
Cecilio Barba ◽  
...  
Keyword(s):  
Discriminant Analysis ◽  
Environmental Conditions ◽  
Anthropogenic Activity ◽  
Freshwater Species ◽  
Fishing Pressure ◽  
Wild Populations ◽  
Morphometric Variation ◽  
Morphological Variations ◽  
Body Development ◽  
The Impact

The Guayas, located in Ecuador, is the largest basin in the Pacific Ocean and has an inventory of 123 native freshwater species. Most of these are endemic species that are threatened or at-risk due to anthropogenic activity and the modification, fragmentation, and destruction of habitats. The aim of this study was to determine the morphometric variation in three wild populations of Brycon dentex in the Guayas basin rivers and their connections to fishing management and environmental conditions. A total of 200 mature fish were captured, and 26 morphometric parameters were measured. The fishing policies (Hypothesis 1) and environmental conditions (Hypothesis 2) were considered fixed factors and were validated by t-tests. The morphological variation among the three populations (Hypothesis 3) was validated through a discriminant analysis. Fishing policies and resource management were found to generate morphological differences associated with body development. In addition, the environmental conditions were found to influence the size and structure of Brycon dentex populations. The analyzed populations were discriminated by the generated morphometric models, which differentiated Cluster 1 (Quevedo and Mocache rivers) with high fishing pressure from Cluster 2 (Pintado river) with medium–low fishing pressure. Morphometric differentiation by discriminant analysis is a direct and economic methodology that can be applied as an indicator of diversity maintenance.

scholarly journals Paracoccidioides brasiliensis Isolated from Nine-Banded Armadillos (Dasypus novemcinctus) Reveal Population Structure and Admixture in the Amazon Basin

2021 ◽  
Vol 7 (1) ◽  
pp. 54
Author(s):  
Eduardo Bagagli ◽  
Daniel Ricardo Matute ◽  
Hans Garcia Garces ◽  
Bernardo Guerra Tenório ◽  
Adalberto Garcia Garces ◽  
...  
Keyword(s):  
Population Structure ◽  
Latin America ◽  
Endemic Area ◽  
Amazon Basin ◽  
Paracoccidioides Brasiliensis ◽  
Pathogenic Fungi ◽  
Sensu Stricto ◽  
Species Level ◽  
Dasypus Novemcinctus ◽  
Show Evidence

Paracoccidioidomycosis is an endemic fungal disease to Latin America caused by at least five species-level genotypes of Paracoccidioides, named P. lutzii, P. brasiliensis (S1a and S1b populations), P. americana, P. restrepiensis, and P. venezuelensis. In this manuscript, we report on Paracoccidioides sp. sampling efforts in armadillos from two different areas in Brazil. We sequenced the genomes of seven Paracoccidioides isolates and used phylogenomics and populations genetics for genotyping. We found that P. brasiliensis and P. lutzii are both present in the Amazon region. Additionally, we identified two Paracoccidioides isolates that seem to be the result of admixture between divergent populations within P. brasiliensis sensu stricto. Both of these isolates were recovered from armadillos in a P. lutzii endemic area in Midwestern Brazil. Additionally, two isolates from human patients also show evidence of resulting from admixture. Our results suggest that the populations of P. brasiliensis sensu stricto exchange genes in nature. More generally, they suggest that population structure and admixture within species is an important source of variation for pathogenic fungi.

scholarly journals Euphausiid community structure and population structure of Euphausia superba off Adélie Land in the Southern Ocean during austral summer 2003, 2005 and 2008

Polar Science ◽  
2011 ◽  
Vol 5 (2) ◽  
pp. 146-165 ◽  
Author(s):  
Atsushi Ono ◽  
Masato Moteki ◽  
Kazuo Amakasu ◽  
Ryoji Toda ◽  
Naho Horimoto ◽  
...  
Keyword(s):  
Population Structure ◽  
Community Structure ◽  
Southern Ocean ◽  
Austral Summer ◽  
Euphausia Superba

scholarly journals Insights into the pan-microbiome: skin microbial communities of Chinese individuals differ from other racial groups

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Marcus H. Y. Leung ◽  
David Wilkins ◽  
Patrick K. H. Lee
Keyword(s):  
Community Structure ◽  
Species Level ◽  
Racial Groups ◽  
Opportunistic Pathogens ◽  
Single Population ◽  
Site Specific ◽  
Skin Site ◽  
Community Membership ◽  
Network Analyses ◽  
Host Properties

Abstract Many studies have characterized microbiomes of western individuals. However, studies involving non-westerners are scarce. This study characterizes the skin microbiomes of Chinese individuals. Skin-associated genera, including Propionibacterium, Corynebacterium, Staphylococcus and Enhydrobacter were prevalent. Extensive inter-individual microbiome variations were detected, with core genera present in all individuals constituting a minority of genera detected. Species-level analyses presented dominance of potential opportunistic pathogens in respective genera. Host properties including age, gender and household were associated with variations in community structure. For all sampled sites, skin microbiomes within an individual is more similar than that of different co-habiting individuals, which is in turn more similar than individuals living in different households. Network analyses highlighted general and skin-site specific relationships between genera. Comparison of microbiomes from different population groups revealed race-based clustering explained by community membership (Global R = 0.968) and structure (Global R = 0.589), contributing to enlargement of the skin pan-microbiome. This study provides the foundation for subsequent in-depth characterization and microbial interactive analyses on the skin and other parts of the human body in different racial groups and an appreciation that the human skin pan-microbiome can be much larger than that of a single population.

Present-day expansion of American beech in northeastern hardwood forests: Does soil base status matter?

2009 ◽  
Vol 39 (12) ◽  
pp. 2273-2282 ◽  
Author(s):  
Louis Duchesne ◽  
Rock Ouimet
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Basal Area ◽  
Base Cation ◽  
Hardwood Forests ◽  
Fagus Grandifolia ◽  
Soil Base ◽  
Large Area ◽  
American Beech ◽  
Permanent Sample Plots

Recently, sugar maple ( Acer saccharum Marsh.) decline in northeastern North America has been regarded as a major factor structuring hardwood forests by favouring American beech ( Fagus grandifolia Ehrh.) in the understory of maple-dominated stands. To determine whether soil fertility differences associated with sugar maple decline may have promoted the expansion of American beech, we explored the relationships between the soil base status and the sapling and tree strata density and composition, using data from 426 permanent sample plots distributed throughout Quebec. Our results indicate that American beech is currently expanding in the sugar maple range of Quebec. The abundance and proportion of American beech in the sapling stratum are mainly associated with the proportion of American beech in the tree stratum, the relative basal area of dead sugar maple trees, and the base status of soils. In accordance with the many studies reporting on the high sensitivity of sugar maple to the acid–base status of soils and the decline of the sugar maple population, this study supports the hypothesis that soil base cation depletion, caused in part by atmospheric acid deposition, is among the main factors involved in the present-day expansion of American beech over a large area in Quebec.

scholarly journals Altitudinally coordinated pattern of plant community structure in the Shivapuri National Park, Nepal

1970 ◽  
Vol 18 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Shalik Ram Sigdel
Keyword(s):  
Community Structure ◽  
Species Diversity ◽  
Plant Species ◽  
Plant Community ◽  
National Park ◽  
Climatic Factors ◽  
Flower Colour ◽  
Basal Area ◽  
Plant Community Structure ◽  
Closed Canopy

Study on plant community structure was undertaken in different altitudinal ranges of Shivapuri National Park. The general objective of this study is to analyse different plant community structure in Shivapuri National Park with regards to altitudinal variation. The forest was divided into three distinct altitudinal ranges on the basis of dominancy. In each altitudinal range standard quadrats method was applied for vegetation analysis. The highest number of species was found in site II. All the ecological parameters of the plant species were higher in site II except Basal Area of tree that was highest in site III. The pattern of distribution of plant species was not uniform according to altitude. At higher elevation, the forest was mature with almost closed canopy and trees were large; so the tree density was low. Species richness was highest in site II. Species diversity among tree and shrub species was higher in site I. But for herb species diversity was higher in site II for both seasons. Such type of variations may be due to nature of soil i.e. acidity, nutrient availability and other micro-climatic factors. The most noteworthy thing was that variation in flower colour of Rhododendron arboreum i.e. deep scarlet at low altitude, but it gradually changed into pinkish white as altitude increased. Key words: Altitude, Density, Plant community, Species diversity doi: 10.3126/banko.v18i1.2161 Banko Janakari, Vol. 18, No. 1, 11-17

scholarly journals ZOOPLANKTON SPATIAL DISTRIBUTION AND COMMUNITY STRUCTURE IN BANGGAI SEA

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Arief Rachman ◽  
Elly Asniariati
Keyword(s):  
Spatial Distribution ◽  
Community Structure ◽  
Hot Spot ◽  
Zooplankton Community ◽  
Anthropogenic Activity ◽  
Zooplankton Abundance ◽  
Total Density ◽  
Importance Value ◽  
Zooplankton Community Structure ◽  
Specific Distribution

<p>Banggai Sea is an interesting ecosystem due to mixing influences from Banda Sea in the west and Maluccas Sea in the east. Therefore, a unique zooplankton community structure and specific distribution pattern should be found in this area. This research was carried on using Baruna Jaya VIII research vessel and samples were collected in 14 sampling stations. Vertical towing using NORPAC plankton net (300 μm) was conducted to collect zooplankton samples. Result showed that inner Mesamat Bay had the lowest abundance of zooplankton, probably due to low water quality resulted from anthropogenic activity. Meanwhile the strait between Liang and Labobo Island had the highest zooplankton abundance in Banggai Sea. Calanoids was the dominant zooplankton taxa in the ecosystem and contributing 55.7% of total density of zooplankton community. The highest importance value made this taxa to be very important factor that regulates the lower trophic level organisms. Results also showed that zooplankton was distributed nearly uniform in eastern but aggregated to several stations in western Banggai Sea. Zooplankton abundance was higher in the central of Banggai Sea, compared to western and eastern area. According to Bray-Curtis clustering analysis the strait between Liang and Labobo Island has unique zooplankton community structure. This might happened due to mixing of water from two highly productive seas that influenced the Banggai Sea ecosystem. From this research we conclude that this strait probably was the zooplankton hot spot area which might also indicate that this area also a hot spot of fishes in the Banggai Sea.</p><p>Keywords: spatial distribution, zooplankton, community structure, hot spot, Banggai</p>

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