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trabalhos:abstracts [2021/05/26 23:51] jennifervasconcelosjdsv2 |
trabalhos:abstracts [2021/09/17 02:28] jennifervasconcelosjdsv2 |
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| Linha 74: | Linha 74: | ||
| ==== Dissertações de Mestrado ==== | ==== Dissertações de Mestrado ==== | ||
| + | === BEL, Renan Lucas Siena Del === | ||
| + | |||
| + | **Tree recruitment in a restinga rainforest: Influence of functional neighborhood and soil** | ||
| + | |||
| + | **Abstract:** While biological communities are complex systems in which numerous mechanisms act in different scales and different processes can generate the same pattern, one way to answer questions regarding the assembly of plant communities is to find correlations between environmental patterns indicative of underlying niche processes with the emerging patterns of a community. Because of that, it is essential to keep developing our understanding on how to represent the niche processes and how to better assess the community structure. In this dissertation we investigate how different environmental variables contribute to our understanding of niche processes. In particular, we are interested in how variables of biotic or abiotic nature interact and contribute to the pattern observed in the structure of the community, and whether the integration of these components is important in identifying the processes involved in community assembly. We use the spatially explicit leaf traits distribution of young (recruited in the last 10 years) individuals from a restinga in Ilha do Cardoso to represent the resulting pattern of the assembly processes, as well as data collected in 2009, to rebuild the neighborhood in which these individuals were recruited. We found that different combinations of biotic and abiotic variables explain different leaf traits distributions, but when we include the young individuals species as a random factor in our models, our results point for no correlation between environmental variables and leaf traits. Because of these conflicting results we infer that while both biotic and abiotic variables work together as predictors of the structure of the community, they do so via species distribution, which is in turn, correlated to an individual's leaf traits values. Thus, environmental variables are only informative when we have no information about the identity of the species. Based on our results, we propose that both types of variables (biotic and abiotic) must be used together when trying to assess the niche processes in a community, as both may be complementary and sometimes interact to form a more complete picture. Together our results open some lines of investigation that may further our knowledge over the mechanisms behind the tree community assembly and may inform future work in the field in order to achieve a better resolution in structure analyses. | ||
| === SOUZA, Luanne Caires da Cruz === | === SOUZA, Luanne Caires da Cruz === | ||
| Linha 144: | Linha 149: | ||
| **Abstract:** The objective of the current research was to investigate if the existing patterns in the adult tree communities can be generated by differences in the aspect related to the regeneration niche of species. Our model of study were two restinga's forests located at the Cardoso Island, on the South coast of São Paulo state. The tall resting forest (TRF) is an older formation, geologically speaking, and it hás closer canopies than the short resting forest (SRF). In the first chapter, we investigated if the abundance inversions of adult trees existing between the TRF and the SRF could be generated due to the differentiated performances of these species at the stage of the seedling, due to the action of the environmental light filter. We assumed as a hypothesis that the species show a worst performance in the stage of seedling in the forest where they are less abundant as adult, due to a trade-off between growth and survival. We expected that the mortality by pathogens was the main cause for the mortality of plants in the more shaded forest. We achieved a manipulative experiment in field with six tree species, in which one-month-old seedlings after germination were transplanted in the two forests and in the nursery. We followed the performance of the species in the two studied forests for nine months. There were no differences in the performance of the two species, except the survival of the Clusia criuva (in the expected way) and of the Tapirira guianensis (opposite to the expected way).Different from what was expected, the main cause of the mortality of all the species was the severe herbivory, and it was not possible to observe a conflict between the growth and the survival of them. In the second chapter, we investigated if the differences in the size of the seeds among the zoochoric tree species can generate differences in the patterns of the adult community and if those differences occur due to an action of the environment lighting filter or only by the differences of the dispersion capacity of the species. We followed the seed rain of the zoochoric tree species for four years in both forests and we could check that the active dispersion capacity of them is negatively related to the size of the seeds, as it can be predicted by both the hypothesis (environmental filter and dispersion capacity). Besides, the relationship between the average production of seeds and the size of the seeds presented a triangular pattern, as species with big seeds always provide low productions. We compared the seeds average sizes and the range of the seeds sizes of the individual plants and of the adult species in both forests (DAP_> 5 cm. We could verify that the TRF presents average size of seeds and range of the seeds's sizes that were bigger than in SRF. Furthermore, the SRF floristic composition is nested in the TRF composition. Therefore, we assumed as a hypothesis that the differences in the dispersal capacity of species, plus the age differences of the forests, are responsible for the distribution of the seeds sizes of the adult plants present in both forests. Finally, in chapter 3, we made a literature review about the role of the soil microorganisms in the specific site of the regeneration of the tropical tree species. We found studies that focus only on the action of the fungi as far in positive interactions (mycorrhizal fungi) as in negative ones (pathogenic fungi). We discussed the main factors and the characteristics associated to the mortality caused by the soil pathogens, as well as the relationship proposed by the pioneer studies which were not confirmed nor tested. | **Abstract:** The objective of the current research was to investigate if the existing patterns in the adult tree communities can be generated by differences in the aspect related to the regeneration niche of species. Our model of study were two restinga's forests located at the Cardoso Island, on the South coast of São Paulo state. The tall resting forest (TRF) is an older formation, geologically speaking, and it hás closer canopies than the short resting forest (SRF). In the first chapter, we investigated if the abundance inversions of adult trees existing between the TRF and the SRF could be generated due to the differentiated performances of these species at the stage of the seedling, due to the action of the environmental light filter. We assumed as a hypothesis that the species show a worst performance in the stage of seedling in the forest where they are less abundant as adult, due to a trade-off between growth and survival. We expected that the mortality by pathogens was the main cause for the mortality of plants in the more shaded forest. We achieved a manipulative experiment in field with six tree species, in which one-month-old seedlings after germination were transplanted in the two forests and in the nursery. We followed the performance of the species in the two studied forests for nine months. There were no differences in the performance of the two species, except the survival of the Clusia criuva (in the expected way) and of the Tapirira guianensis (opposite to the expected way).Different from what was expected, the main cause of the mortality of all the species was the severe herbivory, and it was not possible to observe a conflict between the growth and the survival of them. In the second chapter, we investigated if the differences in the size of the seeds among the zoochoric tree species can generate differences in the patterns of the adult community and if those differences occur due to an action of the environment lighting filter or only by the differences of the dispersion capacity of the species. We followed the seed rain of the zoochoric tree species for four years in both forests and we could check that the active dispersion capacity of them is negatively related to the size of the seeds, as it can be predicted by both the hypothesis (environmental filter and dispersion capacity). Besides, the relationship between the average production of seeds and the size of the seeds presented a triangular pattern, as species with big seeds always provide low productions. We compared the seeds average sizes and the range of the seeds sizes of the individual plants and of the adult species in both forests (DAP_> 5 cm. We could verify that the TRF presents average size of seeds and range of the seeds's sizes that were bigger than in SRF. Furthermore, the SRF floristic composition is nested in the TRF composition. Therefore, we assumed as a hypothesis that the differences in the dispersal capacity of species, plus the age differences of the forests, are responsible for the distribution of the seeds sizes of the adult plants present in both forests. Finally, in chapter 3, we made a literature review about the role of the soil microorganisms in the specific site of the regeneration of the tropical tree species. We found studies that focus only on the action of the fungi as far in positive interactions (mycorrhizal fungi) as in negative ones (pathogenic fungi). We discussed the main factors and the characteristics associated to the mortality caused by the soil pathogens, as well as the relationship proposed by the pioneer studies which were not confirmed nor tested. | ||
| + | |||
| + | === CARVALHO, Gabriel Martins de === | ||
| + | |||
| + | **Influence of stochastic processes on the structuring of community in tabuleiros forest, Bahia, Brazil** | ||
| + | |||
| + | **Abstract:** One of the central objectives of plant ecology is understand the factors that favor the | ||
| + | coexistence of large numbers of species in tropical forests. Previous studies have indicated that | ||
| + | species substitution (beta diversity) may explain the high diversities (alfa) seen in these | ||
| + | forests. Both determinist and stochastic processes can determine species distributions, thus | ||
| + | affecting the substitution rates of species in those communities. Within this context, the present | ||
| + | study evaluated variations in the composition and abundance of tree species, as well as their | ||
| + | morphometric attributes (diameter and height), between two habitat types in Tabuleiro Forests. | ||
| + | Tabuleiro Forests occur on wide coastal plateaus cut by occasional valleys. Edaphic and lightregime characteristics vary between these two topographic units, so that the tree communities | ||
| + | in each would be expected to be different.. A total of 1810 arboreal individuals of 349 | ||
| + | morphospecies DAP > 5 cm were sampled in ten 0.1 ha sampling plots. Comparisons were | ||
| + | made between the plateau and valley habitats in terms of their arboreal composition, structure | ||
| + | and physiognomy. Additionally, the occurrence of possible indicator species in these habitats | ||
| + | was examined. The most abundant species on the plateaus were //Manilkara multifida//, //Eugenia | ||
| + | rostrata//, //Rinorea guianensis// and //Paypayrola blanchetiana//, while //Actinostemon verticilatus//, //E. | ||
| + | rostrata//, //P. blanchetiana// and //Helicostylis tomentosa// were most abundant in valley sites. We | ||
| + | observed a high turnover of species among the plots, even within the same habitats, without the | ||
| + | occurrence of characteristic suites of species in any of them. No significant differences were | ||
| + | observed between the two habitats in terms of total abundance, diameters, tree heights, or total | ||
| + | basal areas. Only Croton macrobothrys among the 349 species sampled demonstrated any | ||
| + | significant association with valley habitats. The species distribution patterns observed suggests | ||
| + | that neutral mechanisms operate in structuring these communities, and that the bulk of the | ||
| + | species observed showed no discernable niche differentiation along the environmental gradient | ||
| + | analyzed. Differences were observed in the abundances of the species among the habitats, | ||
| + | however, exclusive species of a certain habitat were not observed. | ||
| === VAZ, Marcel Carita === | === VAZ, Marcel Carita === | ||
| Linha 158: | Linha 192: | ||
| **Abstract:**Many studies have been proving the importance of positive interactions to the distribution and diversity of species in plant communities. Positive and negative interactions occur simultaneously and the net effect of a species on another is the product of these combined interactions. The objetive of the present study was to evaluate if nitrogen fixing legumes facilitate other tree species in a nitrogen poor environment. We studied the effect of the presence of legumes on the density of species and individuals belonging to two different layers (DBH > 1 cm and 1≤ DBH ≥ 10 cm) around them and also patterns of spatial association between the legumes and other tree species, using a null models approach. The results obtained were dependent on the legume species considered. In chapter 1, the legume Balizia pedicellaris (DC.) Barneby & J.W.Grimes presented higher species density around it, for both layers, although there was no effect on the density of individuals. The species Ormosia arborea Harms did not present effect on the density of species and individuals around it. For the first layer Andira anthelmia (Vell.) J. F. Macbr. did not show effect on the densities, but this species presented a negative effect on the density of species and individuals of the upper layer (1 ≤ DBH ≥ 10 cm), in opposition to our hypothesis. In chapter 2, the spatial association patterns were also distinct between the legume species that showed different species identity associated and different kinds of association (positive or negative). The results indicate that, in spite of belonging to the same functional group, the legumes influence the species around them differently, depending on their morphological and physiological characteristics, as the ability to fix nitrogen in some systems or even the ability to produce alellopathic compounds. | **Abstract:**Many studies have been proving the importance of positive interactions to the distribution and diversity of species in plant communities. Positive and negative interactions occur simultaneously and the net effect of a species on another is the product of these combined interactions. The objetive of the present study was to evaluate if nitrogen fixing legumes facilitate other tree species in a nitrogen poor environment. We studied the effect of the presence of legumes on the density of species and individuals belonging to two different layers (DBH > 1 cm and 1≤ DBH ≥ 10 cm) around them and also patterns of spatial association between the legumes and other tree species, using a null models approach. The results obtained were dependent on the legume species considered. In chapter 1, the legume Balizia pedicellaris (DC.) Barneby & J.W.Grimes presented higher species density around it, for both layers, although there was no effect on the density of individuals. The species Ormosia arborea Harms did not present effect on the density of species and individuals around it. For the first layer Andira anthelmia (Vell.) J. F. Macbr. did not show effect on the densities, but this species presented a negative effect on the density of species and individuals of the upper layer (1 ≤ DBH ≥ 10 cm), in opposition to our hypothesis. In chapter 2, the spatial association patterns were also distinct between the legume species that showed different species identity associated and different kinds of association (positive or negative). The results indicate that, in spite of belonging to the same functional group, the legumes influence the species around them differently, depending on their morphological and physiological characteristics, as the ability to fix nitrogen in some systems or even the ability to produce alellopathic compounds. | ||
| + | |||
| + | === LACERDA, Victória Duarte === | ||
| + | |||
| + | **Structure and vegetation composition of a herbaceous-shrub mussununga in southern Bahia, Brazil** | ||
| + | |||
| + | **Abstract:** Mussununga is a vegetation type present in the Atlantic Forest, occurring on tablelands | ||
| + | in the north of Espirito Santo and southern Bahia. This vegetation occurs on patches of | ||
| + | white sandy soil embedded within forest areas and retains physiognomies similar to | ||
| + | restinga vegetation. This work was performed in a herbaceous/shrub Mussununga area | ||
| + | in southern Bahia, Brazil. Part of this area was subjected to a disturbance in the past due | ||
| + | to the cultivation of //Cocos nucifera L.//, however the cultivation was abandoned. The aim | ||
| + | of this study was to analyze the structure and composition of this plant community and | ||
| + | evaluate the floristic relationships with other areas. The first chapter covers only the | ||
| + | area with no evidence of recent disturbance. The structure and species composition of | ||
| + | this area was described and a floristic analysis was performed to verify similarity | ||
| + | patterns among 20 physiognomic similar areas occurring on white sand soils on the | ||
| + | Atlantic Coast of Brazil. We found 76 species in 37 botanical families and the richest | ||
| + | families were Fabaceae, Orchidaceae and Myrtaceae. The diversity was low | ||
| + | (h'=2.53nats), however the area presented a large environmental heterogeneity. | ||
| + | Floristic analysis showed a strong spatial correlation and low correlation with | ||
| + | environmental variables. In chapter 2, a portion of the area without evidence of recent | ||
| + | disturbance was compared to a portion of disturbed area based onrichness, diversity, | ||
| + | composition and the distribution of functional groups. Richness and diversity were | ||
| + | similar in both areas, however there was a remarkable difference in species | ||
| + | composition. The most abundant species in both areas was //Renvoizea trinii// (Poaceae). | ||
| + | The aggressive species //Pteridium arachnoideum// (Dennstaedtiaceae) increased | ||
| + | considerably in the disturbed area. Functional groups showed significant differences in | ||
| + | their mean coveragein each area. | ||
| + | |||
| + | === MORAES, Adriana de Olinda === | ||
| + | |||
| + | **Effect of anthropized matrices on the epiphyte community of understory in forest fragments of Southern Bahia, Brazil** | ||
| + | |||
| + | **Abstract:** The landscape mosaic of the southern state of Bahia consists of forest fragments, pasture | ||
| + | areas and shaded cacao (//Theobroma cacao L.//) plantations (cabruca). The cacao | ||
| + | agroforestry matrix is considered efficient to the conservation of several species compared | ||
| + | to the other agricultural systems, because it preserves large trees of the original forest. | ||
| + | Therefore, we investigated the influence of the both matrixes on the community of vascular | ||
| + | epiphytes and hemiepiphytes richness and abundance in Wildlife Refuge – Una Biological | ||
| + | Reserve (Revis-REBIO), Una, Bahia, Brazil. Eight plots (10 x10 m) were installed at the | ||
| + | edge (5-10 m) and eight plots in the interior (100 m) of four fragments with cabruca matrix | ||
| + | and four fragments with pasture matrix. A total area of 12.800 m2 was sampled. All trees | ||
| + | with circumference at breast height (CBH) ≥ 5 cm the circumference were measured and | ||
| + | the number of epiphytes and hemiepiphytes was counted up to three meters tall. We | ||
| + | sampled 10.557 trees and 4.057 were phorophytes that housed 57 species of epiphytes and | ||
| + | 30 of hemiepiphytes, distributed in 20 families. A total of 7984 individuals were sampled. | ||
| + | The family with the highest number of species was Araceae (20 spp.) and the most | ||
| + | abundant species was //Philodendron surinamense// (2.150 individuals). About matrix | ||
| + | influence, the interior of fragments surrounded by a pasture matrix had the highest values | ||
| + | of abundance and richness of epiphytes and hemiepiphytes. The abundance of epiphytes | ||
| + | was significantly higher (p<0,001) in the fragments with pasture matrix. Hemiepiphytes | ||
| + | were also more abundant within fragments with pasture matrix. The fragments inserted | ||
| + | into the pasture matrix had significantly (p< 0,02) more species than the fragments | ||
| + | immersed in the cabruca matrix. For hemiepiphytes, the plots of the interior of the | ||
| + | fragments had significantly (p= 0,0007) more species than the edge plots. The edge of | ||
| + | fragments inserted in pasture matrix had a higher average number of trees than the interior | ||
| + | and in plots inserted in the interior of fragments with cabruca matrix, there were a higher | ||
| + | average number of trees than the edge. The largest circumferences and the largest number | ||
| + | of phorophytes were in fragments with pasture matrix. Overall, in cabruca matrix | ||
| + | fragments, the epiphytes and hemiepiphytes occurred on the phorophytes with the larger | ||
| + | perimeter and on interior of pasture matrix fragments, the epiphytes occupied the trees | ||
| + | with larger perimeter and hemiepiphytes occupied both the edge and interior, trees with the | ||
| + | larger CBH The sampling units were not grouped within the same condition. Anetium | ||
| + | citrifolium was an indicator species of the interior of fragments in the pastures matrix. | ||
| === PANNUTI, Márcia Ione da Rocha === | === PANNUTI, Márcia Ione da Rocha === | ||
trabalhos/abstracts.txt · Última modificação: 2021/12/08 01:28 por jennifervasconcelosjdsv2
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