Decomposição e redistribuição de nutrientes das folhas de espécies da floresta de transição Amazônia - Cerrado, MT

The decomposition tax and nutrients flux of senescent andphotosintetically active leaves of three species are different because their regulation depends on the f substract and on the forest type but, the leavesdecomposition also depend on lignin and cellulose compounds find in theleaves. The goal of this study was to evaluate nutrients transference fromsenescent to photosintetically active leaves, decomposition and theircontribution on the nutrients cycling. For that, we quantified leavesnutrients transference and evaluated the decomposition velocity ofsenescent leaves, which were submitted for decomposition in differentplaces, in side of nylon mesh bags soil. The decomposition bags wereremoved to experiment periodically, fifteen to fifteen days in first fourmonths, and after they were removed between 25 to 30 days, but neverless or more than 25 or 30, respectively. The completed decomposition ofleaves was verified around 360 days. The following coefficient of regression:0,0048 ± 0,0005, 0,0059 ± 0,0007, 0,0049 ± 0,0005 are of thedecomposition dynamic for Dialium guianensis, Tovomita schomburgkki eBrosimum lactescens, respectively. The nutrients transference evidences werefound in the senescent and photosintetically active leaves, obtained bychemistry analyze of both leaves.A taxa da decomposição e o fluxo de nutrientes a partir das folhas senescentes às folhas fotossinteticamente ativas de espécies diferentes são distintos, porque sua regulação é feita pela qualidade do substrato e microambiente de cada tipo de floresta. A qualidade do substrato varia com a concentração da celulose e lignina, tornando-o mais resistente à decomposição. O objetivo deste trabalho foi avaliar a redistribuição de nutrientes, a velocidade da decomposição e a contribuição das folhas na ciclagem de nutrientes. Para tanto, folhas senescentes e fotossinteticamente ativas de 3 espécies dominantes foram coletadas, das quais uma parte foi usada para quantificar a redistribuídos de nutrientes na própria planta, enquanto a outra parte de folhas senescentes foi submetida à decomposição em pontos diferentes dentro de sacolas de malha de nylon, com as quais foi determinada a velocidade de decomposição. A retirada das sacolas do experimento foi feita de 15 em 15 dias, nos 4 meses iniciais, e em intervalos de tempo não inferior a 25 e nem superiores aos 30 dias para os restantes meses. A decomposição completa das folhas foi verificada próximo de 360 dias. Os coeficientes de regressão da dinâmica de decomposição foi de 0,0048 ± 0,0005, 0,0059 ± 0,0007, 0,0049 ± 0,0005 para Dialium guianensis, Tovomita schomburgkki e Brosimum lactescens, respectivamente. Foi constatada a redistribuição de nutrientes entre folhas senescentes e fotossinteticamente ativas a partir da diferença de teor de nutrientes, resultante da análise química de ambos os tipos de folhas

Litterfall Chemistry Is Modulated by Wet-Dry Seasonality and Leaf Phenology of Dominant Species in the Tropics

Litterfall has a large influence on carbon and nutrient cycling of ecosystems, particularly in light-limited forested streams, as most nutrients return in the form of litter. Although recent evidence points to the prevalence of seasonal litterfall in species-rich and evergreen tropical riparian forests, there is a limited understanding of how riparian plant diversity intersects with stream and riparian ecosystem functions. To explore this question, we investigate litterfall chemistry across wet and dry seasons and the congruence between litter traits and plant species composition of litterfall in the wet-dry tropics. Using generalized additive models, we observed consistent seasonal patterns of litterfall chemistry over 2 years, mostly influenced by dominant species in litterfall. While drier seasons showed litter lower in nutrients and structural compounds and higher in polyphenols, litter from wetter seasons were nutrient rich but lower in polyphenols. We also found contrasting seasonal patterns in litterfall chemistry, one showing that litterfall nutrient, structural compounds, and secondary metabolite concentrations declined in drier seasons while the other showed that mass-based litterfall inputs increased markedly in drier seasons. Our findings suggest that litterfall chemistry may be altered by shifts in the identity of dominant plant species and seasonality, possibly leading to changes in carbon and nutrient fluxes in tropical riparian ecosystems

Consequências do pós-fogo para a decomposição foliar em riachos tropicais

Queimadas é um distúrbio natural nas paisagens do Bioma Savana. Este estudo avalia os efeitos do pós-fogo (antes e depois) na decomposição de serapilheira na comunidade de invertebrados e biomassa de fungos em diferentes detritos e malhas (fina e grossa) em riacho em curto prazo temporal. Métodos Folhas senescentes (2 ± 0,1 g de peso seco) foram colocadas em sacos (30 × 30 cm, 10 mm – de malha grossa e 0,5 mm - de malha fina) e submersas no fluxo antes e depois do fogo. Sacos replicados (n = 4) foram recuperados após 20 e 40 dias e lavados em uma peneira para separar os invertebrados (densidade, riqueza e grupo trófico funcional) para ambos os tratamentos (antes e após o fogo). Uma série de discos das folhas foi cortada para determinar a massa seca isenta de cinzas e o material restante foi seco em estufa para determinar o peso seco. Resultados O coeficiente médio de decomposição (k = -0,012 dia-1 antes do fogo) corresponde ao intervalo intermediário observado em outros riachos de Savana, com valores menores no pós-fogo (k = -0,007 dia-1). Isso pode ser explicado pelo fogo diminuir a importância da serapilheira alóctone para metabolismo de fluxo devido a aumentar a produção de autóctones (maior abertura do dossel pela queima do mesmo). O coeficiente de decomposição intermediário de todas as diferentes espécies de folhas pós-incêndio pode indicar que o fogo pode equalizar a qualidade da serapilheira em ecossistemas de lóticos. Por outro lado, raspadores (e não fungos ou fragmentadores) pela função de fragmentação foliar (por consumo de perifíton) diminuíram sua abundância (30-50%) no pós-fogo como a perda de massa foliar. Conclusões Isso pode indicar que o pós-fogo modifica as relações de importância dentro das comunidades decompositoras em riachos tropicais.Wildfire is a natural pulsed disturbance in landscapes of the Savannah Biome. This study evaluates short-term post-fire effects on leaf litter breakdown, the invertebrate community and fungal biomass of litter from three different vegetal species in a tropical stream. Methods Senescent leaves of Inga laurina, Protium spruceanum and Rircheria grandis (2 ± 0.1 g dry mass) were individually placed in litter bags (30 × 30 cm: 10 mm coarse mesh and 0.5 mm fine mesh) and submerged in the study stream before and after fire. Replicate bags (n = 4; individually for each species, sampling time, fire event and mesh size) were then retrieved after 20 and 40 days and washed to separate the invertebrates before fire event and again immediately after fire. Disks were cut from leaves to determine ash-free dry mass, while the remaining material was oven-dried to determine dry mass. Results The pre-fire mean decomposition coefficient (k = -0.012 day-1) was intermediate compared to that reported for other savannah streams, but post-fire it was lower (k = -0.007 day-1), due to decreased allochthonous litter input and increased autochthones production. Intermediate k values for all qualities of litter post-fire may indicate that fire is equalizing litter quality in the stream ecosystem. The abundance of scrapers was found to be more important than fungal biomass or shredder abundance, probably due to their functioning in leaf fragmentation while consuming periphyton growing on leaf litter. Conclusions Theses results indicate that fire can modify the relationships within decomposer communities in tropical stream ecosystems

DIVERSIDADE DA FLORA FANEROGÂMICA DE TRÊS MATAS DE GALERIA NO BIOMA CERRADO

O objetivo deste estudo foi avaliar a diversidade vegetal de fanerógamas em três matas de galeria no Distrito Federal, Brasil. O estudo foi realizado na Área de Proteção Ambiental Gama-Cabeça de Veado, a partir do levantamento fitossociológico em 12 parcelas paralelas aos córregos das matas de galerias amostradas, totalizando 3600 m2 de área. Foram identificadas 146 espécies, sendo Fabaceae, Myrtaceae e Rubiaceae as famí­lias mais representativas. Apenas sete espécies ocorreram concomitantemente nas áreas estudadas, indicando elevada diversidade, sobretudo em termos de árvores e arbustos. Os valores de riqueza de espécies e diversidade de Shannon foram maiores no córrego Cabeça-de-Veado (JBB), comparado ao córrego Capetinga (FAL) e Roncador (IBGE), respectivamente. Enquanto que a Dominância Absoluta apresentou maiores valores no córrego Roncador, comparado aos córregos Capetinga e Cabeça-de-Veado, respectivamente. Assim, observamos que a diversidade de espécies está relacionada   heterogeneidade ambiental das matas amostradas, as quais estão relacionadas as caracterí­sticas edáficas e do regime hidrológico

Plant litter dynamics in the forest-stream interface: Precipitation is a major control across tropical biomes

Riparian plant litter is a major energy source for forested streams across the world and its decomposition has repercussions on nutrient cycling, food webs and ecosystem functioning. However, we know little about plant litter dynamics in tropical streams, even though the tropics occupy 40% of the Earth's land surface. Here we investigated spatial and temporal (along a year cycle) patterns of litter inputs and storage in multiple streams of three tropical biomes in Brazil (Atlantic forest, Amazon forest and Cerrado savanna), predicting major differences among biomes in relation to temperature and precipitation regimes. Precipitation explained most of litter inputs and storage, which were generally higher in more humid biomes (litterfall: 384, 422 and 308 g m-2 y-1, storage: 55, 113 and 38 g m-2, on average in Atlantic forest, Amazon and Cerrado, respectively). Temporal dynamics varied across biomes in relation to precipitation and temperature, with uniform litter inputs but seasonal storage in Atlantic forest streams, seasonal inputs in Amazon and Cerrado streams, and aseasonal storage in Amazon streams. Our findings suggest that litter dynamics vary greatly within the tropics, but point to the major role of precipitation, which contrasts with the main influence of temperature in temperate areas. © 2017 The Author(s)

Caracterização da matéria orgânica nas zonas ripárias em diferentes condições de preservação no Cerrado do Planalto Central do Brasil

A vegetação ripária influencia a estrutura e o funcionamento de ecossistemas ripários ao longo de bacias hidrográficas, contribuindo com a estabilidade do canal e proteção de funções ecológicas. Avaliar a entrada da Matéria Orgânica Particulada Grossa (MOPG) e estoque bêntico em escalas temporal e especial e relacionar a entrada da MOPG em riachos com a vegetação ripária preservada e perturbada possibilitam o desenvolvimento de uma visão integrada sobre a ótica de transferência de energia, importante processo ecológico. O objetivo do estudo foi caracterizar a variação espacial e temporal (sazonal e interanual) da MOPG e estoque bêntico e relacionar à contribuição da vegetação ripária na área preservada a perturbada na entrada de MOPG em riachos. A hipótese de tese foi: A MOPG no Cerrado é sazonal e sofre variação interanual porque é influenciada pelos padrões de precipitação da região. O estudado ocorreu em cinco riachos do Cerrado do Planalto Central, dos quais três preservados (Capetinga, Cabeça-de-Veado e Roncador), inseridos na APA Gama Cabeça-de-Veado (Capítulo 1) e dois perturbados (Rio Jardim e Capão Comprido), localizados na zona rural, cuja variação da MOPG foi relacionada a dois riachos preservados (Capetinga e Cabeça-de-veado), para estimar o efeito da remoção parcial da vegetação na entrada de MOPG (Capitulo 2). A tese é composta por dois capítulos: 1 - “Temporal and Spatial Patterns of Inputs and Benthic Stock of Organic Matter in Savannah Streams”, no qual foi investigada a variação da MOPG em riachos preservados durantes dois anos cujo objetivo foi avaliar a variação temporal (sazonal e interanual) e especial de entrada MOPG. O estudo foi baseado nas seguintes hipóteses: i) a quantidade e composição de MOPG variam no espaço e no tempo, porque são influenciadas por características edáficas e tipo de vegetação; e ii) A entrada de MOPG no riacho varia de um ano ao outro, porque é influenciada pelos padrões interanuais de precipitação. Foi coletada mensalmente a MOPG (folhas, galhos, partes reprodutoras e miscelânea) através de aportes (vertical, terrestre e lateral) e estoque bêntico. Os resultados mostraram que, entre meses, a maior quantidade da MOPG entra em riachos no fim da estação seca e início da chuvosa (período de transição). Enter anos, o segundo foi maior que o primeiro nos aportes e não houve diferença significativa no estoque bêntico. Espacialmente, a maior variação da MOPG ocorreu no racho Roncador seguido pelo Cabeça-de-Veado e pelo Riacho Capetinga. No estoque bêntico a maior foi no RS seguido por CVS e por último o CS. As folhas (60 %) da MOPG total foram a maior fração de aportes e 50% do estoque bêntico. No Cerrado a MOPG entra em riachos intensamente no período de transição e continuamente em pequenas quantidades nas estações (seca e chuvosa). Essa tendência de variação da MOPG proporciona uma transferência de energia ininterrupta para a biota aquática e 2 - “Influencias das Áreas Agrícolas na Entrada da Matéria Orgânica Particulada Grossa em Riachos de Cabeceiras Tropicais”. Nesse capítulo, pretendeu-se investigar a influencia da alteração da vegetação ripária, resultante da prática de agropecuária em áreas adjacentes a zona ripária através de entrada mensal de MOPG e composição florística da vegetação a borda do riacho. As hipóteses do trabalho foram: i) A produtividade será menor na área perturbada do que na área preservada, ii) Em função da remoção de parte da vegetação ripária o aporte terrestre (marginal à calha do rio) é menor quando comparado ao vertical (diretamente sobre a calha do riacho), e iii) As zonas ripárias preservadas possuem maior heterogeneidade de espécies arbóreas, contribuindo mais com detritos alóctones para o riacho e maior quantidade de troncos e projeção das raízes, resultando em mais acúmulo da matéria orgânica (estoque bêntico) se comparada à área perturbada. Foi comparada a MOPG de riachos de cabeceira das áreas preservadas e perturbadas. O levantamento florístico foi feito pelo método de parcelas e a coleta da MOPG (folhas, galhos, partes reprodutoras e miscelânea) realizada mensalmente durante dois anos através de aportes (vertical, terrestre, lateral) e estoque bêntico. O efeito da perturbação foi demostrado pela diferença na riqueza de espécies: 111 espécies na área preservada e 79 espécies na perturbadas (em 0.3 ha). O índice de equitabilidade de Pielou (J´) foi similar entre áreas. A maior entrada de matéria orgânica nos aportes e estoque bêntico foi verificada na área perturbada. Entre aportes, o terrestre foi semelhante ao vertical e estes maiores do que o lateral na área preservada. Na área perturbada, onde a vegetação está restrita à borda do riacho, o aporte vertical foi maior do que o terrestre. As folhas constituíram a maior fração na matéria orgânica total nos aportes em ambas as áreas (57 %). No estoque bêntico, os galhos constituíram 52 % na área preservada e as folhas 46% na área perturbada como principais frações da matéria orgânica total. O efeito antrópico foi bastante evidente na contribuição do aporte terrestre, devido à baixa densidade e riqueza de espécies nas comunidades vegetais, sem efeito negativo na matéria orgânica no riacho. A entrada mensal de MOPG no riacho foi contínua, mas em pequenas quantidades e não sincronizada com o clima. As maiores entradas ocorreram no fim da estação seca e inicio da chuvosa. Embora o nosso resultado ainda não seja definitivo, demonstrou que a MOPG varia entre anos, mas os padrões de variações interanuais necessitam de estudos de longo prazo para que sejam esclarecidos os fatores que determinam a produtividade da vegetação ripária. A entrada de MOPG e o estoque bêntico em riachos foram maiores na área perturbada do que na área preservada e o efeito negativo de remoção parcial de vegetação ripária foi evidente no terrestre entre aportes e na densidade e riqueza de espécies. _______________________________________________________________________________________________ ABSTRACTThe riparian vegetation influences the structure and function of riparian ecosystems along the watershed, contributing to channel stability and protection of ecological functions. To evaluate the input of Coarse Particulate Organic Matter (CPOM) and benthic stock on scales (temporal and spatial) and to relate CPOM input and benthic stock between streams enables the development of an integrated vision of the energy transfer point of view, an important ecological process. Our goal was to characterize the spatial and temporal variation of CPOM input and benthic stock and to relate the contribution of preserved and disturbed riparian vegetation in the input and benthic stock. The hypothesis was: The variation of CPOM in the Cerrado is seasonal and interannual because it is influenced by regional weather patterns. Five streams were studied in the Cerrado: three were preserved (Capetinga, Cabeça-de-Veado and Roncador), inserted in the Gama Cabeça-de-Veado preserved environmental area (Chapter 1) and two were disturbed streams, Rio Jardim and Capão Comprido, located in the suburb of Brasília, whose CPOM variation was compared among preserved streams (Capentiga and Cabeça-de-Veado) and disturbed to estimate the effect of partial removal of vegetation in the CPOM inputs and benthic stock (Chapter 2). Therefore, this thesis consists of two chapters that follow: 1 - “Temporal and Spatial Patterns of Inputs and Stock of Organic Matter in Savannah Streams”, where, our goal was to determine if CPOM inputs from riparian vegetation to streams vary naturally over the temporal (seasonal and interannual) and within a small spatial scale (up to 7.5 km), in the tropical savannah (Cerrado), Central Brazil. In addition, we investigated the patterns of organic matter retention, by collecting benthic stocks. The study was based in followed hypotheses: i) the amount and composition of CPOM inputs varies in space and time because they are influenced by edaphic characteristics and vegetation type; and ii) the CPOM inputs vary from one year to another because they are affected by interannual patterns of rainfall. There were annual and seasonal CPOM inputs and benthic stock variations. The highest annual CPOM input was in the second year and the lowest in the first. There were no significant difference variations in the benthic stock between both years. The largest monthly input occurred at the end of the dry season and beginning of the rainy (transition period), but there was no difference between seasons (wet and dry). The spatial CPOM input and benthic stock between areas were different. The higher CPOM input occurred in the Roncador stream followed by Cabeça-de-Veado and Capetinga stream. And the largest benthic stock was in the Roncador stream followed by Cabeça-de-Veado and Capetinga. The leaves were 60% higher in the CPOM input and 50% in the benthic stock. In the Cerrado CPOM enters intensely in the stream during the transition period and continuously in the small quantities in the both seasons (wet and dry). This tendency of entrances of CPOM provides an uninterrupted energy transfer to heterotrophic organisms. And 2 - " Influences of Agricultural Areas in the Organic Matter Inputs Into Tropical Headwater Streams " In this chapter, we intend to determine the magnitude of human impact resulting from the partial removal of vegetation for agricultural activity in the transfer of energy between the riparian zone through the monthly CPOM input and composition of riparian vegetation confined to the edge of stream. For this, we compared four Cerrado headwater streams (two preserved) and (the two disturbed). The hypotheses of the study were: i) the productivity will be less at disturbed area than at preserved area, ii) Due to the partial removal of riparian vegetation the terrestrial input contribution (marginal to the river channel) is lower when compared to vertical input (directly on stream edge), and iii) preserved riparian areas have greater diversity of tree species, contributing more with allochthonous CPOM to the stream and greater amount of branches and projection of the roots, resulting in accumulation of organic matter (benthic stock) compared to the disturbed area. The floristic survey was conducted by plots method and the CPOM (leaves, brunches, reproductive parts and miscellaneous) was sampled monthly for two years through vertical, terrestrial and, lateral inputs and benthic stock. The partial vegetation remove effect was demonstrated by the difference in species richness: 111 species in the preserved area and 79 species in disturbed (at 0.3 ha). The evenness index Pielou (J') was similar in both areas. Among inputs, the terrestrial was similar to the vertical and these larger than the lateral input at the preserved area. At disturbed area, where the riparian vegetation is restricted in the stream edge, vertical input was higher than the terrestrial input. The leaves were the largest fraction of total organic matter and they were similar in both areas (preserved and disturbed -57%). In the benthic stock, the branches constituted 52% in the preserved area and leaves 46% in the disturbed area as the largest fraction of the total CPOM. The anthropic effect was quite evident in the terrestrial input contribution, due to low density and species richness in plant communities, but it did not decrease CPOM amount entering into the stream, which can result in changes in the functioning of ecosystems of streams and structure biological communities. Monthly CPOM inputs in the streams are continuous in small amounts and not synchronized with climate. The peaks occurred in the end and beginning of wet season. Although our results are not definitive it showed that there was interannual variation, but the Inter-annual patterns variations need longer term studies to clarify the factors that determinate the vegetation riparian productivity between years. The CPOM input and benthic stock were higher at perturbed area than at preserved area. Between inputs the negative effect of partial removal of riparian vegetation was evident in the terrestrial input, low density and species richness

High within‐stream replication is needed to predict litter fluxes in wet–dry tropical streams

Streams draining forested landscapes are fuelled by terrestrial plant litter, which can be transported downstream or retained and broken down locally. However, fluxes of plant litter in streams can vary at multiple spatio‐temporal scales, affecting the availability of this key resource in heterotrophic stream food webs. To explore this question we quantified several processes related to litter dynamics (i.e. litter inputs, storage, losses by transport and losses by breakdown) by sampling litter at multiple sites in three streams of the Brazilian Cerrado biome (which has a tropical wet–dry climate) for 2 years. We assessed the relative contribution of different spatial (among and within streams) and temporal scales (annual, seasonal and monthly) to total variability of these processes (hereafter fluxes). Spatial and temporal variability of fluxes were both high, but spatial variation was 1.67‐fold greater than temporal variation (61 versus 37%, respectively), especially at the within‐stream scale (50% overall); an exception was litterfall, which varied less spatially than temporally (24 versus 76%). Temporal variation of litter storage (and hence availability to consumers) was mostly seasonal and due to differences in net transport. Inputs and transport were higher in the wet than the dry season (wet versus dry season, 1.45 versus 0.92 and 1.43 versus 0.06 g litter m−2 day−1), while breakdown was similar between both seasons (0.88 versus 0.94 g litter m−2 day−1). Storage (i.e. accumulation) rate was positive and negative in the dry and wet season, respectively, indicating that litter was stored in the dry season and exported in the wet season. The transitional dry–wet season showed the highest inputs, breakdown and storage (3.21, 1.63 g litter m−2 day−1 and 145 g litter m−2), while the wet–dry season showed lower inputs (as in the dry season), higher transport (as in the wet season) and lower breakdown and storage than the other seasons (0.93, 0.65, 0.31 g litter m−2 day−1 and 24 g litter m−2). Our results underscore the role of variation in biophysical drivers of litter fluxes within streams (e.g. pool–riffle configuration, substrate features, biological communities), and suggest that high within‐stream replication is necessary to study litter fluxes at larger scales and over time. The seasonal patterns suggested potential changes in litter dynamics under future climate scenarios in the tropics, including increased storage due to reduced transport in a drier climate

High within‐stream replication is needed to predict litter fluxes in wet–dry tropical streams

Streams draining forested landscapes are fuelled by terrestrial plant litter, which can be transported downstream or retained and broken down locally. However, fluxes of plant litter in streams can vary at multiple spatio‐temporal scales, affecting the availability of this key resource in heterotrophic stream food webs. To explore this question we quantified several processes related to litter dynamics (i.e. litter inputs, storage, losses by transport and losses by breakdown) by sampling litter at multiple sites in three streams of the Brazilian Cerrado biome (which has a tropical wet–dry climate) for 2 years. We assessed the relative contribution of different spatial (among and within streams) and temporal scales (annual, seasonal and monthly) to total variability of these processes (hereafter fluxes). Spatial and temporal variability of fluxes were both high, but spatial variation was 1.67‐fold greater than temporal variation (61 versus 37%, respectively), especially at the within‐stream scale (50% overall); an exception was litterfall, which varied less spatially than temporally (24 versus 76%). Temporal variation of litter storage (and hence availability to consumers) was mostly seasonal and due to differences in net transport. Inputs and transport were higher in the wet than the dry season (wet versus dry season, 1.45 versus 0.92 and 1.43 versus 0.06 g litter m−2 day−1), while breakdown was similar between both seasons (0.88 versus 0.94 g litter m−2 day−1). Storage (i.e. accumulation) rate was positive and negative in the dry and wet season, respectively, indicating that litter was stored in the dry season and exported in the wet season. The transitional dry–wet season showed the highest inputs, breakdown and storage (3.21, 1.63 g litter m−2 day−1 and 145 g litter m−2), while the wet–dry season showed lower inputs (as in the dry season), higher transport (as in the wet season) and lower breakdown and storage than the other seasons (0.93, 0.65, 0.31 g litter m−2 day−1 and 24 g litter m−2). Our results underscore the role of variation in biophysical drivers of litter fluxes within streams (e.g. pool–riffle configuration, substrate features, biological communities), and suggest that high within‐stream replication is necessary to study litter fluxes at larger scales and over time. The seasonal patterns suggested potential changes in litter dynamics under future climate scenarios in the tropics, including increased storage due to reduced transport in a drier climate

DIVERSIDADE DA FLORA FANEROGÂMICA DE TRÊS MATAS DE GALERIA NO BIOMA CERRADO

O objetivo deste estudo foi avaliar a diversidade vegetal de fanerógamas em três matas de galeria no Distrito Federal, Brasil. O estudo foi realizado na Área de Proteção Ambiental Gama-Cabeça de Veado, a partir do levantamento fitossociológico em 12 parcelas paralelas aos córregos das matas de galerias amostradas, totalizando 3600 m2 de área. Foram identificadas 146 espécies, sendo Fabaceae, Myrtaceae e Rubiaceae as famí­lias mais representativas. Apenas sete espécies ocorreram concomitantemente nas áreas estudadas, indicando elevada diversidade, sobretudo em termos de árvores e arbustos. Os valores de riqueza de espécies e diversidade de Shannon foram maiores no córrego Cabeça-de-Veado (JBB), comparado ao córrego Capetinga (FAL) e Roncador (IBGE), respectivamente. Enquanto que a Dominância Absoluta apresentou maiores valores no córrego Roncador, comparado aos córregos Capetinga e Cabeça-de-Veado, respectivamente. Assim, observamos que a diversidade de espécies está relacionada   heterogeneidade ambiental das matas amostradas, as quais estão relacionadas as caracterí­sticas edáficas e do regime hidrológico