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trabalhos:abstracts [2021/05/27 00:46] jennifervasconcelosjdsv2 |
trabalhos:abstracts [2021/05/27 01:18] jennifervasconcelosjdsv2 |
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| **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 === | === MORAES, Adriana de Olinda === | ||
trabalhos/abstracts.txt · Última modificação: 2021/12/08 01:28 por jennifervasconcelosjdsv2
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