scholarly journals Population structure and density of Attalea phalerata Mart. ex Spreng. (Arecaceae) in a semideciduous forest

2012 ◽  
Vol 36 (4) ◽  
pp. 637-645 ◽  
Author(s):  
Aelton Biasi Giroldo ◽  
André R. Terra Nascimento ◽  
Pedro Paulo Ferreira Silva ◽  
Gastão Viegas Pinho Júnior

The structure of a population can be seen as the result of biotic and abiotic interacting forces. The studies of population characteristics are vital to improve the understanding of ecosystem functioning. In this study, we attempted to answer the two following questions: What are the population structure of Attalea phalerata? and Are there any influence of reproducers presence, canopy openness, declivity, basal area and soil coverage on recruitment of individuals in this population? We distinguished four ontogenetic stages in A. phalerata. Reproducers and virgins were sampled by using 25 plots (400 m²), juveniles and seedlings were sampled in sub-plots (100 m²). We found 2,328 Attalea phalerata individuals per hectare, first two ontogenetic stages accounted for 89.8% of the total, describing a relatively stable population. None of the analyzed factors were affecting the natural regeneration of Attalea phalerata in the fragment. The density and distribution pattern found for the population are probably signs of formation of oligarchic forests, moreover, the species seems to be able to colonize clearings and open areas.

2020 ◽  
Vol 11 ◽  
pp. e3330
Author(s):  
Patrícia Oliveira da Silva ◽  
Jessica Barros Cabral Valente ◽  
Patricia Lacerda Silva ◽  
Carolina Ferreira Gomes ◽  
Gisele Cristina de Oliveira Menino

Knowing the regeneration and structure of a species in different phytophysiognomies is extremely important to understand its pattern of occurrence. In spite of its importance, this type of study is still scarce in the Cerrado biome. In this perspective, this work aimed to compare the structure of the arboreal and regenerating strata of Annona coriacea in the cerrado sensu stricto and in the cerradão (savanna woodland). For that purpose, 13 plots of 400m² were installed in each physiognomy. All individuals of A. coriacea were sampled and had their diameter and height measured. The individuals were divided into regenerating and arboreal and were distributed in classes of height and diameter. Furthermore, the absolute density and the basal area of each extract were calculated in each physiognomy. The parameters were compared using the T-test. In total, 130 individuals of A. Coriacea were sampled, with 42 regenerating individuals in the cerrado sensu stricto and 49 in the cerradão. As for the arboreal individuals, 33 were sampled in the cerrado sensu stricto and 6 in the cerradão. All evaluated parameters revealed to be significantly different for the physiognomies. Based on these results, it is possible to affirm that A. coriacea did not present a distribution pattern in the two physiognomies, although it presents a better establishment success in the cerrado sensu stricto. In the cerradão, although the seeds can germinate, the seedlings fail to develop and reach the adult age.


2019 ◽  
Vol 3 (3) ◽  
pp. 106
Author(s):  
Laís Alvares Fonseca ◽  
Francisco de Assis Braga ◽  
Geanderson Santiago Fernandes

The natural regeneration of tree species in forested areas has been studied by several researches. This study aimed to evaluate the natural regeneration of tree species in Corymbia citriodora (Hook.) K. D. Hill & L. A. Johnson planted forest understory in Florestal, Minas Gerais, Brazil. Individuals with diameter at breast height (DBH) ≥ 5 cm were evaluated in seven 25 x 4 m plots randomly distributed. A phytosociological survey was carried out and the ecological groups and the dispersal syndromes of the regenerants were determined. We found 28 species belonging to 12 families, among which Fabacea and Annonaceae stood out. Density was 1,557 regenerants ha-1, and basal area was 23 m2 ha-1. The most important species were Psidium sp; Schefflera macrocarpa (Cham. & Schltdl.) Frodin; Pera  glabrata (Schott) Poepp. ex Baill.; Astronium fraxinifolium Schott & Spreng.; Matayba guianensis Aubl.; and Plathymenia reticulata Benth. We found 35% pioneer, 40% early secondary, 18% late secondary, and 7% climax species, of which 57% are zoochoric, 40% anemochoric, and 3% autochoric. It is concluded that the natural regeneration in the understory studied comprises typical species of the Seasonal Semideciduous Forest of the Atlantic Forest biome, presenting significant density and individuals from all ecological groups.The natural regeneration of tree species in forested areas has been studied by several researches. This study aimed to evaluate the natural regeneration of tree species in Corymbia citriodora (Hook.) K. D. Hill & L. A. Johnson planted forest understory in Florestal, Minas Gerais, Brazil. Individuals with diameter at breast height (DBH) ≥ 5 cm were evaluated in seven 25 x 4 m plots randomly distributed. A phytosociological survey was carried out and the ecological groups and the dispersal syndromes of the regenerants were determined. We found 28 species belonging to 12 families, among which Fabacea and Annonaceae stood out. Density was 1,557 regenerants ha-1, and basal area was 23 m2 ha-1. The most important species were Psidium sp; Schefflera macrocarpa (Cham. & Schltdl.) Frodin; Pera  glabrata (Schott) Poepp. ex Baill.; Astronium fraxinifolium Schott & Spreng.; Matayba guianensis Aubl.; and Plathymenia reticulata Benth. We found 35% pioneer, 40% early secondary, 18% late secondary, and 7% climax species, of which 57% are zoochoric, 40% anemochoric, and 3% autochoric. It is concluded that the natural regeneration in the understory studied comprises typical species of the Seasonal Semideciduous Forest of the Atlantic Forest biome, presenting significant density and individuals from all ecological groups.


Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 129
Author(s):  
Tamalika Chakraborty ◽  
Albert Reif ◽  
Andreas Matzarakis ◽  
Somidh Saha

European beech (Fagus sylvatica L.) trees are becoming vulnerable to drought, with a warming climate. Existing studies disagree on how radial growth varies in European beech in response to droughts. We aimed to find the impact of multiple droughts on beech trees’ annual radial growth at their ecological drought limit created by soil water availability in the forest. Besides, we quantified the influence of competition and canopy openness on the mean basal area growth of beech trees. We carried out this study in five near-natural temperate forests in three localities of Germany and Switzerland. We quantified available soil water storage capacity (AWC) in plots laid in the transition zone from oak to beech dominated forests. The plots were classified as ‘dry’ (AWC < 60 mL) and ‘less-dry’ (AWC > 60 mL). We performed dendroecological analyses starting from 1951 in continuous and discontinuous series to study the influence of climatic drought (i.e., precipitation-potential evapotranspiration) on the radial growth of beech trees in dry and less-dry plots. We used observed values for this analysis and did not use interpolated values from interpolated historical records in this study. We selected six drought events to study the resistance, recovery, and resilience of beech trees to drought at a discontinuous level. The radial growth was significantly higher in less-dry plots than dry plots. The increase in drought had reduced tree growth. Frequent climatic drought events resulted in more significant correlations, hence, increased the dependency of tree growth on AWC. We showed that the recovery and resilience to climatic drought were higher in trees in less-dry plots than dry plots, but it was the opposite for resistance. The resistance, recovery, and resilience of the trees were heterogeneous between the events of drought. Mean growth of beech trees (basal area increment) were negatively impacted by neighborhood competition and positively influenced by canopy openness. We emphasized that beech trees growing on soil with low AWC are at higher risk of growth decline. We concluded that changes in soil water conditions even at the microsite level could influence beech trees’ growth in their drought limit under the changing climate. Along with drought, neighborhood competition and lack of light can also reduce beech trees’ growth. This study will enrich the state of knowledge about the ongoing debate on the vulnerability of beech trees to drought in Europe.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tassiana Maylla Fontoura Caron ◽  
Victor Juan Ulises Rodriguez Chuma ◽  
Alexander Arévalo Sandi ◽  
Darren Norris

AbstractDegraded Amazonian forests can take decades to recover and the ecological results of natural regeneration are still uncertain. Here we use field data collected across 15 lowland Amazon smallholder properties to examine the relationships between forest structure, mammal diversity, regrowth type, regrowth age, topography and hydrology. Forest structure was quantified together with mammal diversity in 30 paired regrowth-control plots. Forest regrowth stage was classified into three groups: late second-regrowth, early second-regrowth and abandoned pasture. Basal area in regrowth plots remained less than half that recorded in control plots even after 20–25 years. Although basal area did increase in sequence from pasture, early to late-regrowth plots, there was a significant decline in basal area of late-regrowth control plots associated with a decline in the proportion of large trees. Variation in different forest structure responses was explained by contrasting variables, with the proportion of small trees (DBH < 20 cm) most strongly explained by topography (altitude and slope) whereas the proportion of large trees (DBH > 60 cm) was explained by plot type (control vs. regrowth) and regrowth class. These findings support calls for increased efforts to actively conserve large trees to avoid retrogressive succession around edges of degraded Amazon forests.


2021 ◽  
Vol 13 (8) ◽  
pp. 1513
Author(s):  
Dominik Seidel ◽  
Peter Annighöfer ◽  
Christian Ammer ◽  
Martin Ehbrecht ◽  
Katharina Willim ◽  
...  

The structural complexity of the understory layer of forests or shrub layer vegetation in open shrublands affects many ecosystem functions and services provided by these ecosystems. We investigated how the basal area of the overstory layer, annual and seasonal precipitation, annual mean temperature, as well as light availability affect the structural complexity of the understory layer along a gradient from closed forests to open shrubland with only scattered trees. Using terrestrial laser scanning data and the understory complexity index (UCI), we measured the structural complexity of sites across a wide range of precipitation and temperature, also covering a gradient in light availability and basal area. We found significant relationships between the UCI and tree basal area as well as canopy openness. Structural equation models (SEMs) confirmed significant direct effects of seasonal precipitation on the UCI without mediation through basal area or canopy openness. However, annual precipitation and temperature effects on the UCI are mediated through canopy openness and basal area, respectively. Understory complexity is, despite clear dependencies on the available light and overall stand density, significantly and directly driven by climatic parameters, particularly the amount of precipitation during the driest month.


2021 ◽  
Author(s):  
Yihan Cai ◽  
Takahiro Nishimura ◽  
Hideyuki Ida ◽  
Mitsuru Hirota

&lt;p&gt;&amp;#160;Soil respiration (Rs) is the second largest carbon flux between the atmosphere and terrestrial ecosystem. Because of the large proportion, even small change in Rs would considerably impact the global carbon cycle. Therefore, it is important to accurately estimate Rs by taking its spatial and temporal variation into consideration. While the temporal variation of Rs and its controlling factors have been well-described, large unexplainable part still has been remained in the spatial variation of Rs especially in the forest ecosystems with complex structures. The objective of this study is to fill the knowledge gap about spatial variation of Rs and its controlling factors in a typical mature beech forest in Japan. Hypotheses of this study were, 1) Rs would show large spatial variation in the mature beech forest, 2) the spatial variation of Rs was mainly influenced by soil water content (SWC) and soil temperature (ST), 3) the two key factors were determined by the forest structures. This study was conducted in a 1- ha permanent study plot in the mature beech forest with significant gap-mosaic structures. To examine these hypotheses, Rs, SWC, ST and parameters related to forest structure, i.e. sum of basal area, diameter at breast height, number of trees, number of species within a radius of 5 m from the Rs measurement points, and canopy openness were measured at 121 points in different season between 2012 to 2013. In this study, all the measurements of Rs were conducted by using alkali-absorption technique.&lt;/p&gt;&lt;p&gt;&amp;#160;Coefficient of variation of Rs was between 25 - 28 % which was similar to that of SWC in all the measurements. The spatial variation of Rs was relatively higher in July, August and September than that in June and October. There was no significant relationship in the spatial variation between Rs and ST in all the measurements, meanwhile, Rs was well explained by SWC in measurements conducted in August, September and October. Multiple linear regression analysis indicated that canopy openness and sum of basal area showed significant positive and negative correlation with SWC, respectively. And canopy openness explained SWC much more than sum of basal area did. This result suggested that SWC, the key factor determined the spatial variation of Rs, cannot be only explained by stems distribution and their characteristics, but also canopy architecture in the forest ecosystem.&lt;/p&gt;


2008 ◽  
Vol 25 (3) ◽  
pp. 403-412 ◽  
Author(s):  
Patrícia Calil ◽  
Carlos A. Borzone

Mysidacea are common sublittoral crustaceans that inhabit all coasts in the world. In this study, the population characteristics and the reproductive biology of Metamysidopsis neritica Bond-Buckup & Tavares, 1992 were studied in the surf zone of a south Brazilian beach (Atami). Mysids were sampled at monthly intervals from August, 1999 to July, 2000 (total of 29,490 individuals). Individuals were classified into six population categories. The highest abundance occurred in May (8,665) and August (6,415), and lowest in September (336) and December (368). Three main generations were identified, namely the summer, fall and winter generations. The winter generation was the longest (four to five months). The fall generation lasted four months, and the summer one extended from three to four months. Ovigerous females occurred throughout the year, with a greater proportion in July. The number of eggs or larvae varied from one to 16. Weak associations were found between female length and egg number, egg volume, and the number of larvae with and without eyes. Egg volume increased during the coldest season, whereas the smallest values were recorded during summer. These results suggest a possible direct relationship between egg volume and generation longevity.


2010 ◽  
Vol 40 (11) ◽  
pp. 2164-2174 ◽  
Author(s):  
Sarah E. Stehn ◽  
Christopher R. Webster ◽  
Janice M. Glime ◽  
Michael A. Jenkins

We investigated the influence of fine-scale elevational gradients and overstory disturbance on bryophyte distribution, diversity, and community composition. Bryophyte species cover and richness were sampled across 60 randomly selected plots within high-elevation spruce–fir ( Picea – Abies ) forests of Great Smoky Mountains National Park. Ordination and regression analyses revealed a fine-scale elevation gradient (700 m) in bryophyte community composition. Observed changes in bryophyte diversity and community composition were also associated with variation in deciduous basal area and thus litter composition, the prevalence of herbaceous plants, and the degree of canopy openness resulting from balsam woolly adelgid ( Adelges piceae Ratz.) infestation. Although overstory disturbances, such as those caused by the adelgid, create suitable substrate for bryophyte colonization, the corresponding increase in light availability and deciduous basal area may alter bryophyte diversity and community assemblages.


2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Elisa Morais Paschoal ◽  
Arthur Duarte Vieira ◽  
Thiago José Ornelas Otoni ◽  
Aglaia Maciel Gripp ◽  
Jessica Pereira Freire ◽  
...  

This study aimed to describe and compare the floristic and structural component of the tree component, as well as the alpha and beta diversity, as well as the floristic similarity of a remnant of Semideciduous Forest. The tree vegetation was sampled at two edges in contact with pasture (BP) and coffee growing (BC), and inside the fragment (INT). 2.840 individuals were sampled, identified in 56 families, 144 genera and 271 species (94 BC, 128 BP and 178 INT). The border stretches were characterized by higher density and smaller basal area than the interior, indicating the occurrence of disturbances. The variations in the structural floristic composition of the tree communities wereinfluenced by regional and local environmental variations, as well as the historical use of the area, according to Niche and Intermediate Disturbance Theories.


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