Dahum

ABSTRACT Studies on the dynamics of ecosystems undergoing restoration are needed to verify whether they are following the expected trajectory, developing in unexpected ways, or becoming stabilized in a non desirable intermediate stage of blocked succession. In order to elucidate the successional trajectory of the plant community in a 20 ha patch of riparian Atlantic Forest (southeastern Brazil) undergoing restoration, we assessed native tree and shrub species regenerating at 18, 28 and 38 years after planting. We analyzed changes in floristic composition and proportions of functional traits, by comparison with the set of 166 species originally planted most of which were non-native, and with the plant assemblages of two reference riparian ecosystems - a primary-type and a secondary forest, in the same eco-region. Despite isolation from extant forests, immigrating native species have enriched and dominated the community undergoing restoration. Thus, the floristic composition and the proportions of species among functional guilds is becoming more distinct through time from the set of species planted and more similar to the nearest secondary forest (1.6 km), but is still dramatically different from that of a primary forest 50 km away. The proportions of functional guilds among individuals regenerating have shown stability over time but differ in general from the primary forest, particularly for the higher proportion of zoochorous plants in the forest undergoing restoration. The proportion of non-native species as well as of individuals of these species in the community have decreased over time, even though they were the majority of the species planted, refuting the hypothesis of priority effect driving the community assembly.

A utilização de ecossistemas naturais como meta a ser atingida e a seleção de indicadores para monitoramento dos projetos são temas controversos na ciência e na prática da restauração. Analisamos a vegetação ripária em quatro remanescentes de Floresta Estacional Semidecidual, para verificar se alguns atributos dessas comunidades se repetem em diferentes locais, podendo ser referência para esta região fitogeográfica. Instalamos dez parcelas de 100 m² em cada local, amostramos plantas lenhosas com altura ≥ 0,5 m, divididas em estrato regenerante (DAP < 5 cm) e estrato arbóreo (DAP ≥ 5 cm) e classificamos as espécies com base em atributos funcionais, raridade e status de ameaça. Contabilizamos lianas, pteridófitas e árvores com epífitas. As variáveis estruturais de densidade (estrato arbóreo e regenerante e árvores com epífitas), área basal e cobertura de copas não diferiram entre locais. Foram pouco variáveis entre as áreas a riqueza rarefeita para 100 indivíduos no estrato arbóreo...

A restauração ecológica no Brasil se intensificou nas últimas décadas, passando por uma série de transformações conceituais e de paradigmas. No princípio, a restauração era conduzida para restabelecer serviços ecossistêmicos e a riqueza e a origem das espécies utilizadas não era questionada. Atualmente, plantios em alta diversidade e somente com o uso de espécies nativas são recomendados. Com o objetivo de verificar se o número de espécies nativas e exóticas utilizadas na restauração de matas ciliares tem se modificado ao longo do tempo, analisamos 44 projetos implantados de 1957 a 2008, localizados no estado de São Paulo, em região anteriormente ocupada por Floresta Estacional Semidecidual (FES). Em cada local efetuamos o levantamento das árvores plantadas em área total de 1.000 m², subdividida em parcelas aleatoriamente distribuídas. Classificamos como exóticas todas as espécies que não ocorrem naturalmente em região de FES. O número total de espécies amostradas por local variou d...

ABSTRACT Forest restoration by planting trees often accelerates succession, but the trajectories towards reference ecosystems have rarely been evaluated. Using a chronosequence (4-53 years) of 26 riparian forest undergoing restoration in the Brazilian Atlantic Forest, we modeled how the variables representing forest structure, tree species richness and composition, and the proportion of plant functional guilds change through time. We also estimated the time required for these variables reach different types of reference ecosystems - old-growth forest, degraded forest and secondary forest. Among the attributes which follow a predictable trajectory over time are: the basal area, canopy cover, density and tree species richness, as well as proportions of shade tolerant and slow growing species or individuals. Most of the variation in density of pteridophythes, lianas, shrubs and phorophythes, proportion of animal-dispersed individuals, rarefied richness and floristic similarity with reference ecosystems remain unexplained. Estimated time to reach the reference ecosystems is, in general, shorter for structural attributes than for species composition or proportion of functional guilds. The length of this time varies among the three types of reference ecosystems for most attributes. For instance, tree species richness and proportion of shade tolerant or slow growing individuals become similar to secondary forests in about 40 years, but is estimated to take 70 years or more to reach the old-growth forest. Of all the variables considered, canopy cover, basal area, density and richness of the understory – by their ecological relevance and predictability – are recommended as ecological indicators for monitoring tropical forest restoration success.

... Townsend, CR; Begon, M. & Harper, JL 2003. Essentials of ecology. 2ª edição. Blackwell Science, Oxford. (Agradecimentos: Agradecemos ao Prof. Glauco Machado pela orientação nesse trabalho e ao programa do curso de Ecologia do Pantanal da UFMS)

Knowledge about the biogeographic affinities of the world's tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world's tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry for...

Forest restoration by planting trees often accelerates succession, but the trajectories toward reference ecosystems have rarely been evaluated. Using a chronosequence (4–53 years) of 26 riparian forest undergoing restoration in the Brazilian Atlantic Forest, we modeled how the variables representing forest structure, tree species richness and composition, and the proportion of plant functional guilds change through time. We also estimated the time required for these variables to reach different types of reference ecosystems: old-growth forest (OGF), degraded forest, and secondary forest. Among the attributes which follow a predictable trajectory over time are: the basal area, canopy cover, density and tree species richness, as well as proportions of shade tolerant and slow growing species or individuals. Most of the variation in density of pteridophythes, lianas, shrubs and phorophythes, proportion of animal-dispersed individuals, rarefied richness and floristic similarity with refe...

Studies on the dynamics of ecosystems undergoing restoration are needed to verify whether they are following the expected trajectory, developing in unexpected ways, or becoming stabilized in a non desirable intermediate stage of blocked succession. In order to elucidate the successional trajectory of the plant community in a 20 ha patch of riparian Atlantic Forest (southeastern Brazil) undergoing restoration, we assessed native tree and shrub species regenerating at 18, 28 and 38 years after planting. We analyzed changes in floristic composition and proportions of functional traits, by comparison with the set of 166 species originally planted most of which were non-native, and with the plant assemblages of two reference riparian ecosystems — a primary-type and a secondary forest, in the same eco-region. Despite isolation from extant forests, immigrating native species have enriched and dominated the community undergoing restoration. Thus, the floristic composition and the proportion...