Local scale variation in plant assemblage’s attributes in the semi-arid region, Northeastern Brazil

Variations in physiognomy and structure associated to abiotic factors in local scale rarely are reported for the typical vegetation of Northeastern Brazil semi-arid, Caatinga. It was tested if six adjacent biotopes with distinct altitudinal (450-690m) and pedological aspects present different woody plant attributes (structure and physiognomy). A total of 2,055 stems, 23 families, 64 species/ morpho-species were recorded. Clear altitudinal or pedological local-scale gradient could not be defined along a priori defined biotopes, which hold in fact two phytocoenoses: Plateau Summit, at greatest altitude, with distinct physiognomy and exclusive taxa; and lower altitude assemblage, presenting physiognomic and structural similarit

Conhecimentos de Ecologia Utilizados por Alunos do Ensino Médio na Compreensão das Questões Ambientais

Nas questões ambientais estão inseridos conceitos da Ciência Ecologia e da Biologia da Conservação e que podem apresentar diferentes significados dependendo dos atores sociais. O objetivo deste estudo foi verificar se os alunos do Ensino Médio utilizavam conhecimentos da Ciência Ecologia na compreensão das questões ambientais. Foi realizada uma pesquisa de cunho qualitativo com as informações obtidas por meio de uma questão sobre poluição hídrica e tratadas a partir da Análise do Conteúdo. Foram identificadas três categorias de análise: Educação, Solução Técnica e Poder Público. Os estudantes do Ensino Médio fizeram pouco uso dos conceitos da Ciência Ecologia, apresentando termos superficiais, generalistas e de senso comum

DINÂMICA DA VEGETAÇÃO EM UM FRAGMENTO DE MATA ATLÂNTICA NO NORDESTE DO BRASIL

http://dx.doi.org/10.5902/1980509817442To test the hypothesis that the physiognomy, structure and dynamics of woody species are influenced by the spatial gradient edge-interior, data were collected from these parameters in 2004, 2007 and 2010 in an Atlantic forest fragment. Species were sampled for the Canopy (DS), with circumference > 15 cm to 1.3 m MARTÍNEZ-soil and understory (SB) in circumference between ground level> 3 cm and CAP 150 m from the forest boundary), and analyzed 1,000 m² per site, divided into plots of 10 m², to measure individuals of higher class. In each plot a sub-plot of 5 m² for sampling understory was installed. Branches were collected from three adult individuals from the species to obtain the density of the wood. The number of individuals (NI), basal area (BA), mortality (TM), recruitment rate (TR), periodic annual diameter increment (IPA), loss rate (P) and gain rate (G) Area and basal turnover rates in number of individuals (TN) and basal area (TA) class tree component in the three locations showed no significant edge effect. At the edge, the understory had lower values of NI and AB and higher TM than in the forest interior. Differences between the strata occur regardless of edge sealing, since young plants present in most individuals in the sample class SB, which are more sensitive than adult trees to changes caused by the creation of the edge. Rates of loss and gain of AB and AB turnover in NI and in SB presented higher values than on the DS, which points to a stratum with larger changes. In DS there were no differences in species richness among environments differs from that observed in SB. The floristic composition of the DS in environments closer to the forest limit was quite distinct from that of the interior, indicating that there has been no recovery of floristic composition. All environments SB had low similarity. The edges of the DS and SB had a higher concentration of individuals in class intervals smaller density values timber. The DS has already recovered biomass, although the edge and intermediate environments have not recovered species composition late. The SB still suffers the edge effect. Possibly, the highest concentration of individuals is in class with lower density wood result on edge.http://dx.doi.org/10.5902/1980509817442Para testar a hipótese que a fisionomia, estrutura e dinâmica de espécies lenhosas são influenciadas pelogradiente espacial borda-interior, foram coletados dados desses parâmetros em 2004, 2007 e 2010 em umfragmento de Floresta Atlântica. Foram amostradas para o Dossel (DS), plantas com circunferência docaule a altura do peito (CAP) > 15 cm e do sub-bosque (SB) com circunferência ao nível do solo entre >3 cm e CAP 150 m do limite florestal), sendo analisados 1000m² por local, divididos em parcelas de 10 m², para medir os indivíduos de maior classe. Em cada parcelafoi instalada uma subparcela de 5 m² para amostragem do sub-bosque. Foram recolhidos ramos de trêsindivíduos adultos das espécies, para obtenção da densidade da madeira. O número de indivíduos (NI), áreabasal (AB), taxa de mortalidade (TM), taxa de recrutamento (TR), incremento periódico anual em diâmetro(IPA), taxa de perda (P) e ganho (G) de área basal e as taxas de rotatividade em número de indivíduos (TN)e em área basal (TA) da classe do componente arbóreo nos três locais evidenciaram não haver efeito deborda significativo. Na borda, o sub-bosque teve menores valores de NI e AB e maiores TM, que no interiordo fragmento. Diferenças entre os estratos acontecem, independentemente do selamento da borda, já queplantas jovens na maior classe amostral apresentam indivíduos no SB, que são mais sensíveis que as árvoresadultas às mudanças causadas pela criação da borda. Taxas de perda e ganho de AB e de rotatividade em NI eAB, no SB, apresentaram valores maiores que no DS, o que aponta para um estrato com maiores mudanças.No DS não ocorreram diferenças de riqueza de espécies entre os ambientes, distinto do observado no SB.A composição florística no DS nos ambientes mais próximos ao limite florestal foi bastante distinta que ado interior, indicando que ainda não houve recuperação da composição florística. Todos os ambientes doSB tiveram baixa similaridade. As bordas do DS e SB apresentaram maior concentração de indivíduos emintervalos de classe de menores valores de densidade de madeira. O DS já recuperou a biomassa, embora osambientes de borda e intermediário não tenham recuperado a composição de espécies tardias. O SB aindasofre efeito de borda. Possivelmente, a maior concentração de indivíduos em classe de menor densidade damadeira sendo resultado na borda

Influence of functional traits on the demographic rates of 47 arboreal species in a tropical forest in northeastern Brazil

Influence of functional traits on the demographic rates of 47 arboreal species in a tropical forest in northeastern Brazil. Based on the premise that species use different strategies for acquiring and maintaining resources, it is possible to identify their similarities as determined by particular trade-offs between traits, the present work examined the specific leaf area (SLA), basic wood density (BWD), maximum height (Hmax) and seed shape (SS) of 47 arboreal species in an moist semi-evergreen tropical forest in northeastern Brazil and investigated the influence of those traits on plant mortality rates (MR) and growth (BAG). BWD and Hmax were the best predictors of mortality rates. Factorial analysis explained 70.4% of the total variability, distributed among three factors composed of traits and rates. MR and Hmax were found to be more readily observed when orthogonally rotated by the varimax method, with the first factor explaining 26.9% of the variance. Cluster analyses and principal component analyses, whose matrices contained the variables MR, BAG, SLA, and Hmax for each species, confirmed the discriminant analysis and allowed the identification of four functional groups. The fact that some of the correlations encountered differed from previously published results (such as the negative relationship between maximum height and mortality) may reflect regional climatic seasonality or indicate that this strategy benefits plant species that reach the upper canopy and thus become well-established

DYNAMICS OF VEGETATION IN AN ATLANTIC FOREST FRAGMENT IN NORTHEASTERN BRAZIL

Para testar a hip\uf3tese que a fisionomia, estrutura e din\ue2mica de esp\ue9cies lenhosas s\ue3o influenciadas pelo gradiente espacial borda-interior, foram coletados dados desses par\ue2metros em 2004, 2007 e 2010 em um fragmento de Floresta Atl\ue2ntica. Foram amostradas para o Dossel (DS), plantas com circunfer\ueancia do caule a altura do peito (CAP) > 15 cm e do sub-bosque (SB) com circunfer\ueancia ao n\uedvel do solo entre > 3 cm e CAP < 15 cm em um gradiente borda-interior formado h\ue1 35 anos. Em 2004, foram avaliadas tr\ueas posi\ue7\uf5es no fragmento: borda, intermedi\ue1ria e interior (> 150 m do limite florestal), sendo analisados 1000 m\ub2 por local, divididos em parcelas de 10 m\ub2, para medir os indiv\uedduos de maior classe. Em cada parcela foi instalada uma subparcela de 5 m\ub2 para amostragem do sub-bosque. Foram recolhidos ramos de tr\ueas indiv\uedduos adultos das esp\ue9cies, para obten\ue7\ue3o da densidade da madeira. O n\ufamero de indiv\uedduos (NI), \ue1rea basal (AB), taxa de mortalidade (TM), taxa de recrutamento (TR), incremento peri\uf3dico anual em di\ue2metro (IPA), taxa de perda (P) e ganho (G) de \ue1rea basal e as taxas de rotatividade em n\ufamero de indiv\uedduos (TN) e em \ue1rea basal (TA) da classe do componente arb\uf3reo nos tr\ueas locais evidenciaram n\ue3o haver efeito de borda significativo. Na borda, o sub-bosque teve menores valores de NI e AB e maiores TM, que no interior do fragmento. Diferen\ue7as entre os estratos acontecem, independentemente do selamento da borda, j\ue1 que plantas jovens na maior classe amostral apresentam indiv\uedduos no SB, que s\ue3o mais sens\uedveis que as \ue1rvores adultas \ue0s mudan\ue7as causadas pela cria\ue7\ue3o da borda. Taxas de perda e ganho de AB e de rotatividade em NI e AB, no SB, apresentaram valores maiores que no DS, o que aponta para um estrato com maiores mudan\ue7as. No DS n\ue3o ocorreram diferen\ue7as de riqueza de esp\ue9cies entre os ambientes, distinto do observado no SB. A composi\ue7\ue3o flor\uedstica no DS nos ambientes mais pr\uf3ximos ao limite florestal foi bastante distinta que a do interior, indicando que ainda n\ue3o houve recupera\ue7\ue3o da composi\ue7\ue3o flor\uedstica. Todos os ambientes do SB tiveram baixa similaridade. As bordas do DS e SB apresentaram maior concentra\ue7\ue3o de indiv\uedduos em intervalos de classe de menores valores de densidade de madeira. O DS j\ue1 recuperou a biomassa, embora os ambientes de borda e intermedi\ue1rio n\ue3o tenham recuperado a composi\ue7\ue3o de esp\ue9cies tardias. O SB ainda sofre efeito de borda. Possivelmente, a maior concentra\ue7\ue3o de indiv\uedduos em classe de menor densidade da madeira sendo resultado na borda.To test the hypothesis that the physiognomy, structure and dynamics of woody species are influenced by the spatial gradient edge-interior, data were collected from these parameters in 2004, 2007 and 2010 in an Atlantic forest fragment. Species were sampled for the Canopy (DS), with circumference > 15 cm to 1.3 m soil and understory (SB) in circumference between ground level> 3 cm and CAP <15 cm on edge-gradient formed within 35 years. In 2004, we assessed three positions in the fragment: edge, intermediate and inner (> 150 m from the forest boundary), and analyzed 1,000 m\ub2 per site, divided into plots of 10 m\ub2, to measure individuals of higher class. In each plot a sub-plot of 5 m\ub2 for sampling understory was installed. Branches were collected from three adult individuals from the species to obtain the density of the wood. The number of individuals (NI), basal area (BA), mortality (TM), recruitment rate (TR), periodic annual diameter increment (IPA), loss rate (P) and gain rate (G) Area and basal turnover rates in number of individuals (TN) and basal area (TA) class tree component in the three locations showed no significant edge effect. At the edge, the understory had lower values of NI and AB and higher TM than in the forest interior. Differences between the strata occur regardless of edge sealing, since young plants present in most individuals in the sample class SB, which are more sensitive than adult trees to changes caused by the creation of the edge. Rates of loss and gain of AB and AB turnover in NI and in SB presented higher values than on the DS, which points to a stratum with larger changes. In DS there were no differences in species richness among environments differs from that observed in SB. The floristic composition of the DS in environments closer to the forest limit was quite distinct from that of the interior, indicating that there has been no recovery of floristic composition. All environments SB had low similarity. The edges of the DS and SB had a higher concentration of individuals in class intervals smaller density values timber. The DS has already recovered biomass, although the edge and intermediate environments have not recovered species composition late. The SB still suffers the edge effect. Possibly, the highest concentration of individuals is in class with lower density wood result on edge

Who is who in the understory: the contribution of resident and transitory groups of species to plant richness in forest assemblages

The forest understory is made up of resident and transitory species and can be much richer than the canopy. With the purpose to describe the contribution of these groups to the woody understory, five Atlantic Forest fragments were selected and studied in Northeastern Brazil. In order to analyze the understory&#8217;s structure, the sample included woody individuals with circumference at breast height (CBH) smaller than 15cm and circumference at ground level (CGL) greater than 3cm, regardless of height. The recorded species were quantified and classified into functional stratification categories (resident and transitory), and the floristic similarity between the understory and the tree stratum was calculated. Species&#8217; importance in the understory was analyzed by height and total natural regeneration classes based on a regeneration index. The understory was richer in species (median=63.8, SD=21.72, n=5 fragments) than the tree stratum (43.8, 18.14, 5), and the similarity between these components was relatively high (median=0.54, SD=0.09). The results also showed that the studied understory in the forest fragments was mainly composed by transitory species (median=67.01%, SD=3.76), that were well distributed among height classes and had the highest densities, which may favor their future presence in the canopy&#8217;s structure and composition. The typical understory species were grouped into two strata: the lower understory, made up of species that generally do not reach more than 4m in height (mostly species from families Piperaceae, Rubiaceae and Melastomataceae); and the upper understory, with intermediate heights between the lower understory and the canopy, but with average heights that were not higher than 10m (mainly of species from families Anonnaceae, Clusiaceae and Myrtaceae). These families&#8217; richness was commonly used as an indicator of the vegetation&#8217;s successional stage; however, such results must be seen with caution as they show that these families co-occurred and were highly important in different strata. Studying the understory is fundamental because it represents a floristically rich stratum with a unique structure, which promotes the natural regeneration of the tree stratum.<br>El sotobosque forestal está compuesto por especies residentes y transitorias. Con el objetivo de describir la contribución de esos grupos en el sotobosque leñoso, cinco fragmentos de Bosque Atlántico fueron seleccionados en el nordeste de Brasil. El muestreo incluyó individuos con circunferencia a la altura del pecho (CPA)<15cm y con circunferencia a la altura del suelo (CAS)&#8805;3cm. Las especies fueron cuantificadas y clasificadas en residentes o transitorias y la similitud florística entre el sotobosque y el dosel fue calculada. El sotobosque se mostró más rico en especies (mediana=63.8, DS=21.72, n=5 fragmentos) que el dosel (43.8, 18.14, 5) y la similitud entre esos componentes fue relativamente alta (0.54, 0.09). El sotobosque está compuesto principalmente de especies transitorias (mediana=67.01%, DS=3.76) las cuales están bien distribuidas entre las clases de altura y presentan las mayoresdensidades. Las especies residentes fueron agrupadas en dos estratos: el sotobosque bajo (<4m de altura, la mayoría Piperaceae, Rubiaceae y Melastomataceae); y el sotobosque superior (altura media <10m, principalmente Anonnaceae, Clusiaceae y Myrtaceae). El estudio del sotobosque es fundamental porque es un estrato florísticamente rico con un estructura única, lo cual promueve la regeneración natural del estrato arbóreo