Navegando por Assunto "Serapilheira"

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Acesso aberto (Open Access)
Atributos químicos do solo e interação com folhas de serapilheira em manguezais da ilha de Itarana e comunidade Caranã, São João de Pirabas, Pará, Brasil
(Universidade Federal do Pará, 2013-04-26) SOUZA, Marina Lopes de; MOTA, Maria Aurora Santos da; http://lattes.cnpq.br/5817549281617240; RUIVO, Maria de Lourdes Pinheiro; http://lattes.cnpq.br/9419564604488031
Mangroves are coastal ecosystems situated in the land-sea interface, under constant influence of the dynamics of the tides. It is known that this ecosystem is considered one of the most productive in the world, due to the large amount of organic matter that is produced and fed into other environments. This productivity, in turn, has its origin both in litterfall produced within the system itself, the inputs of nutrients arising tidal and storm water. The nutrient dynamics in mangroves is linked to factors such as the frequency of flooding by tides, the seasonal period, the topography and biogeochemical processes. In this context, this study aims to evaluate the soil chemical properties and verify the interaction between soil and leaf litterfall in mangroves in northeast Pará, in the rainy and less rainy season. For this, samples of soil and leaf litterfall were collected in different seasonal periods, for analyses of pH, Eh, interstitial salinity, C, N, S, P, Fe, Na +, K +, Ca + 2, Mg + 2 and Al + 3. The results of soil chemical properties show that seasonality exerted greater influence on the results of Na +, K + and interstitial salinity. The intertidal mangrove presented nutrient content of higher soil when compared to the supramaré mangrove. In general, there was a relation to the concentration of the soil nutrients with the concentration of nutrients in leaf litterfall, more evident in the high carbon concentration, as well as the lifting conditions content of some nutrients in leaf litterfall of supramaré mangrove during the rainy season.
Acesso aberto (Open Access)
Castanhal nativo da Floresta Nacional do Tapajós: atributos edáficos, produção de serapilheira e perfil socioeconômico dos extrativistas
(Universidade Federal do Pará, 2017-08-07) GUERREIRO, Quêzia Leandro de Moura; RUIVO, Maria de Lourdes Pinheiro; http://lattes.cnpq.br/9419564604488031
The seed Brazil nuts has high food value and is considered one of the main extractive products of the export zone of the northern region of Brazil. The study of the ecological and biological aspects of Brazil nuts (Bertholletia excelsa) has been the objective of many studies, but the amount of research that approach the social and environmental variables related to the species is incipient. In this context, the present thesis sought to evaluate the edaphic attributes that most influence in plant development and litter production in the native castanhal area of the Tapajós National Forest (Tapajós FLONA), in addition to studying the socioeconomic factors and management practices, collection and the production of extractivists of Brazil nuts that reside in this area. The presentation of the obtained results was exposed in three chapters: the first chapter includes a geostatistical analysis of the physical-chemical factors of the soil; the second presents an estimate of the litter production in relation to the monthly average of the maximum temperature and the monthly totals of precipitation and insolation; and the third shows an analysis of the economic, social and management aspects of the Brazil nuts collectors that work in the Tapajós FLONA. The field samples were performed in a permanent 300 m x 300 m portion of the MapCast project, installed at km 84 of the Tapajós FLONA. The soil sample collections for the physico-chemical analyzes followed the recommendations described in the "Manual of laboratory: soil, water, plant nutrition, animal nutrition and food" of Embrapa, as well as the procedures for analytical determinations. For the litter collection, 12 containers were used in circular format and the deposited material was collected every 30 days and separated into classes (leaves, flowers and fruits, woody, miscellaneous). Socioeconomic, production and the form of extraction data of Brazil nuts were obtained through a structured interview conducted with 24 extractivists from the region. By Simple Kriging it was possible to estimate the concentration of nutrients studied for the entire area of the sample grid. The densification of Brazil nut trees was identified in areas with higher silt and clay values and lower values for macroporosity, pH, phosphorus, zinc and copper. Leaf production ranged from 169.9 to 965.6 kg ha-1 month-1, wood between 26.7 and 501.3 kg ha-1 month-1 and flowers and fruits between 0.6 and 19.6 kg ha-1 month-1. The wood and flowers and fruit classes presented no significant variation (p> 0.05) and no significant correlation with any meteorological variable. The three environmental variables analyzed explain 40.7% of the temporal variability of litter production. In all, 39 Brazil nuts extractivists were recorded. Most of these have a low level of education and are covered by the “Bolsa Família Program”. The production varied significantly between the 2013/2014, 2014/2015 and 2015/2016 harvests, and extraction practices are traditional. The Geostatistical Analysis allowed the knowledge of the current spatial distribution of the physical and chemical attributes of the soil in the studied area, which will serve as a basis of comparison for future evaluations in the same place and also to help understand environmental aspects in areas with agglomerations of Brazil nuts. The environmental variables temperature and insolation influence leaf production and total litter production in native castanhal area. The management practices of the castanhal and the collection and processing of the seeds applied by the extractivists of the studied communities do not present any innovation in relation to the traditional and rudimentary practices already informed in the literature. The variation between the harvests was influenced by the reduction of rains (caused by an event of El Niño installed in 2015) and by the frequent burned, according to the perception of the interviewees.
Acesso aberto (Open Access)
Dinâmica de serapilheira e produção de raízes finas em plantios de Paricá (Schizolobium Parahyba Var. Amazonicum) e floresta sucessional em Aurora do Pará, Amazônia Oriental
(Universidade Federal do Pará, 2009-06-29) SILVA, Antonio Kledson Leal; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543
The establishment of silviculturals and agroforestry systems with the paricá (Schizolobium parahyba var. amazonicum) expanded in the state of Pará, brazil, usually as alternative to reforestation of degraded areas (abandoned pasture). However lacking basic studies on the cycling of organic matter to understand the potencial of paricá to recover degrades areas. Set up an experiment on the farm Tramontina, Aurora do Pará, to evaluate process connected with cycling of organic matter, how the litter production (litterfall), litter stock, production of fine root during 12 months (October 2007 and September 2008), in treatments with plantations of paricá with five years, in the following arrangement: paricá single (PS), consortium paricá + freijó (Cordia goeldiana) (PF), Agroforestry systems with paricá, freijó and curauá (Ananas comusus var. erectifolius) (PFC). This treatments with paricá was compared with an area of reference (successional forest ecosystem with 25 years of age) (SUC). The treatments of paricá presented annual litter production under SUC (8,79 ± 0,08 Mg ha-1 yr-1), no significant difference between treatments PS (6,05 ± 0,15 Mg ha-1), PF (6,08 ± 0,13 Mg ha-1 yr-1) and PFC (6,63 ± 0,13 Mg ha-1 yr-1). The monthly production of litter was significativety major in dry season than wet season. The largest stock of litter has been identified in treatments with paricá PS (7,7 ± 1,0 Mg ha-1) and PF (7.4 ± 0,1 Mg ha-1), while the SUC presented an stock of 5.9 ± 1,3 Mg ha-1. This results is related to the lower rate of decomposition found in treatments with paricá. The production of total fine roots (live + dead) was significativelly major in the treatments PS (380,3 ± 20,6 g m-²), PF (343,0 ± 18,4 g m-²) and PFC (265,5 ± 9,9 g m-²) than SUC (107,2 ± 2,7 g m-²), the variation of fine roots production in the period of study is associate with a seasonality of pluviometric precipitation; the fine roots production decreases during the period of increased precipitation and increases with the arrival of the dry period. Treatments with paricá showed good ability to provide organic material above and below the ground. More specifically, the paricá presented high production and storage of litter on soil, which are desirable attributes in systems for recovery of degraded areas.
Acesso aberto (Open Access)
Mangrove vegetation in Amazonia: a review of studies from the coast of Pará and Maranhão States, north Brazil
(Instituto Nacional de Pesquisas da Amazônia, 2008) MENEZES, Moirah Paula Machado de; BERGER, Uta; MEHLIG, Ulf
The present study is a compilation of the literature about vegetation of mangrove forest of the north coast of Brazil. It synthesizes the knowledge about this important ecosystem and lists the currently available literature. The study focuses on the coast of Pará and Maranhão states, which are covered by a continuous belt of mangroves. The mangrove flora comprises six mangrove tree species and several associated species. Mangrove tree height and stem diameter vary as a function of abiotic local stand parameters. Seasonal variation in rainfall and salinity affect the species' phenology and litter fall. Local population use products derived from mangrove plants for different purposes (e.g. fuel; medicinal; rural construction). The increase in the coastal population has given rise to conflicts, which impact on mangrove forest.
Acesso aberto (Open Access)
O papel de espécies arbóreas e fatores edáficos na variação espacial do sistema serapilheira em uma floresta de terra firme na Amazônia: conhecimento e perspectivas para a conservação
(Universidade Federal do Pará, 2020-11-13) QUEIROZ, Maria Elisa Ferreira de; LAVELLE, Patrick; http://lattes.cnpq.br/5850683517396587; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543; https://orcid.org/0000-0003-2364-8822
The dense ombrophilous forest, also known as tropical rain forest, is a formation that presents great complexity in the composition, distribution and density of species and occupies a good part of the Brazilian Amazon. In the region, the differences between plant communities and animals form a mosaic divided into eight areas or centers of endemism, separated by the main rivers, with their own biota and evolutionary relationships, three of which (Belém, Xingu and Tapajós) are entirely Brazilian. The Belém endemism center is the most threatened by deforestation and small-scale local investigations are essential to understand the effects of this disturbance on the functioning of the forest. The decomposition of litter is one of the key factors of this functioning and occurs in a hierarchical sequence of interaction processes mediated by climatic factors (temperature and humidity), physical properties of the soil, chemical limitations related to the sources of resources and biological regulation (micro and macroorganisms). In this research, it was discovered that sensitive changes in the structure of a primary forest threatened by urban growth, caused by the intensity of the natural succession dynamics, altered the humus system, since the organisms' competition for nutrients depleted the soil during the regeneration of areas affected by falling trees. Thus, the physical-chemical conditions of the forest soil became a selective filter of tree species and the major factors in the decomposition hierarchy, since temperature and humidity had little variation in the system. Then, leaves of specific tree species of the humus system, which formed a finer structure, determined the diversity of saprotrophic fungi positively related to the better quality of these leaves and the soil. Conversely, where the litter morphology was thicker and more structured, there was an increase in the diversity of litter transforming macrofauna, to the detriment of earthworm populations, which preferred higher quality leaves and soil. Soilplant-decomposer interactions are indicators of decomposition speed in humus systems, with consequent formation of mosaics of litter spots with different decomposition dynamics. Thus, places where humus function was classified as Mesomull or Oligomull were characterized by soils with a high available carbon content and good cation exchange capacity. Mull type humus systems are sensitive to variations in soil quality and earthworm activity. This explained the change to the Dysmull humus system in areas with large leaves, characterized by low nutrient availability, as confirmed in the soils of these places, although a slow functioning may indicate a conservative state of organic matter. The methodology proved to be favorable to predict changes at different scales that may affect the forest restoration.
Acesso aberto (Open Access)
O papel de espécies arbóreas e fatores edáficos na variação espacial do sistema serapilheira em uma floresta de terra firme na Amazônia: conhecimento e perspectivas para a conservação
(Universidade Federal do Pará, 2020-11-13) QUEIROZ, Maria Elisa Ferreira de; LAVELLE, Patrick; http://lattes.cnpq.br/5850683517396587; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543; https://orcid.org/0000-0003-2364-8822
The dense ombrophilous forest, also known as tropical rain forest, is a formation that presents great complexity in the composition, distribution and density of species and occupies a good part of the Brazilian Amazon. In the region, the differences between plant communities and animals form a mosaic divided into eight areas or centers of endemism, separated by the main rivers, with their own biota and evolutionary relationships, three of which (Belém, Xingu and Tapajós) are entirely Brazilian. The Belém endemism center is the most threatened by deforestation and small-scale local investigations are essential to understand the effects of this disturbance on the functioning of the forest. The decomposition of litter is one of the key factors of this functioning and occurs in a hierarchical sequence of interaction processes mediated by climatic factors (temperature and humidity), physical properties of the soil, chemical limitations related to the sources of resources and biological regulation (micro and macroorganisms). In this research, it was discovered that sensitive changes in the structure of a primary forest threatened by urban growth, caused by the intensity of the natural succession dynamics, altered the humus system, since the organisms' competition for nutrients depleted the soil during the regeneration of areas affected by falling trees. Thus, the physical-chemical conditions of the forest soil became a selective filter of tree species and the major factors in the decomposition hierarchy, since temperature and humidity had little variation in the system. Then, leaves of specific tree species of the humus system, which formed a finer structure, determined the diversity of saprotrophic fungi positively related to the better quality of these leaves and the soil. Conversely, where the litter morphology was thicker and more structured, there was an increase in the diversity of litter transforming macrofauna, to the detriment of earthworm populations, which preferred higher quality leaves and soil. Soilplant-decomposer interactions are indicators of decomposition speed in humus systems, with consequent formation of mosaics of litter spots with different decomposition dynamics. Thus, places where humus function was classified as Mesomull or Oligomull were characterized by soils with a high available carbon content and good cation exchange capacity. Mull type humus systems are sensitive to variations in soil quality and earthworm activity. This explained the change to the Dysmull humus system in areas with large leaves, characterized by low nutrient availability, as confirmed in the soils of these places, although a slow functioning may indicate a conservative state of organic matter. The methodology proved to be favorable to predict changes at different scales that may affect the forest restoration.