RESUMO -(Diversidade de herbáceas em microhabitats rochoso, plano e ciliar em uma área de caatinga, Caruaru, PE, Brasil). Objetivou-se avaliar a influência da heterogeneidade micro-espacial no aumento da fitodiversidade herbácea em uma área de caatinga de Caruaru, Pernambuco, Brasil. Microhabitats rochosos, planos e ciliares foram selecionados, e nesses foi realizado um levantamento qualiquantitativo das herbáceas ocorrentes em 35 parcelas de 1 m 2 , em cada microhabitat. Todas as ervas nas parcelas foram contadas, marcadas e identificadas, coletando-se também outras espécies herbáceas ocorrentes entre as parcelas. A riqueza taxonômica total de herbáceas foi mais elevada ao se considerar o conjunto dos microhabitats. A flora total foi de 62 espécies, 42 destas ocorrendo no microhabitat rochoso, 32 no plano e 39 no ciliar. O índice de similaridade florística de Jaccard entre os microhabitats variou de 42% (plano × ciliar) a 57% (rochoso × plano). Isoladamente, as riquezas de espécies nos microhabitats plano, rochoso e ciliar foram de 3,09; 3,88 e de 4,18 espécies (ln ind.)-1 e as diversidades, pelo índice de Shannon-Wiener, foram de 2,08; 2,09 e de 2,52 nats.ind.-1 , respectivamente. Malvaceae, Euphorbiaceae e Poaceae apresentaram maior número de espécies. A densidade total de herbáceas foi de 4.009 ind.105 m -2 , sendo 1.749 indivíduos do microhabitat rochoso, 1.020 do ciliar e 1.240 do plano. Cerca de 19% das espécies eram trepadeiras e foram consideradas como um grupo importante para conservação da biodiversidade local. Evidenciou-se a importância da inclusão das herbáceas dos diferentes microhabitats, para a determinação da riqueza florística da caatinga. Palavras-chave: riqueza de espécies, densidade de herbáceas, semi-árido, caatinga, microsítiosABSTRACT -(Diversity of herb plants in three microhabitats at a caatinga site: level area, rocky area and stream border area, Caruaru, PE, Brazil). The influence of the micro spatial heterogeneity in the diversity of herb plants was evaluated in a caatinga site at Caruaru, Pernambuco, Brazil. Three microhabitats were chosen: a flat area with a rocky yellow podzolic soil, a similar area with the same soil type but without rocks and an area at the border of a small intermittent stream but that is never covered by floods. In each microhabitat, 35 plots, 1m 2 each, were marked, at random, and all herb plants identified and counted. Plants were also collected and identified in the same microhabitats outside the plots. A total of 62 species were found in the three microsites, 32 in the flat area, 42 in the rocky area and 39 in the stream area. Similarity, using Jaccard index, ranged from 42% (flat x stream area) to 57% (flat and rocky area). . Malvaceae, Euphorbiaceae and Poaceae were the families with highest number of species. About 19% of the species were climbing plants and were considered an important group for local biodiversity conservation. The importance of the inclusion of the herb plants of the different microhabitats for the determination of the floristic rich...

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Palavras-chave: caatinga, florística, formas de vida, herbáceas, solosABSTRACT -(Herbaceous floristic study and relationship with soil of crystalline shield and sedimentary basin caatinga areas at Petrolândia, Pernambuco State, Brazil). Floristic surveys were carried out in two close caatinga areas, one on the crystalline shield and the other on a sedimentary basin, both at Petrolândia, Pernambuco, Brazil, with the objective of identifying differences between the two areas in composition, habit and life form of the herbaceous flora. One hundred 1×1 m plots were established in each area and all the herbaceous species were identified. Soil samples were collected at 0-20 and 20-40 cm depths. In general, the soil in the crystalline shield area was shallower, had greater clay content, with higher water holding capacity, and was more fertile. The number of families, genera and species in the sedimentary basin and crystalline shield areas were 32, 62 and 78 and 31, 53 and 69, respectively. The floristic similarity between the areas was high (75%). The clustering analysis showed that the floristic arrangements between the sampled plots are more similar within the areas than between areas, suggesting the existence of distinct groups. Soil type seems not to be a factor determining the floristic similarity, habit or life forms of the caatinga vegetation herbs when the areas are near, but it may influence the occurrence and the frequency of some species.

Variations in leaf morphometry and in diameter and height growth of plants may occur due to changes in light and temperature conditions of the forest in order to compensate the stress in the habitat. In this study, we examine the relationship of seedling and juvenile size and leaf area of woody species in forests of different ages ([55 and 19 years) in northeastern Brazil. A total of 600 individuals of four species, seedlings and juveniles that survived a rainy season were evaluated. Seedlings and juveniles of Croton blanchetianus Baill, Poincianella pyramidalis (Tul.) L. P. Queiroz, Myracrodruon urundeuva Allemão and Commiphora leptophloeos (Mart.) J.B. Gillett were measured for height and stem diameter in the beginning of the rainy season of 2014. One leaf of each individual was collected in the beginning of the rainy season. Leaves were photographed, and leaf area was measured. Differences in height, diameter and leaf area between forests and the existence of a relationship of diameter and height to leaf area were examined. Leaf area and seedling and juvenile size of C. blanchetianus and C. leptophloeos decreased as succession progressed. However, this was not observed for seedlings of P. pyramidalis and juveniles of M. urundeuva. Leaf area explained 7-26% of the variation in size of individuals in the young forest and 11-39% of the variation in size of individuals in the mature forest. Despite variations in leaf area, significant changes in growth rate were not found with the increase in forest age for most ontogenetic stages and species.

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The Tropical dry forests cover large regions of the world and have been extensively altered by human activities. This study was aimed at characterizing and comparing the density, diversity and structural parameters of a human-altered secondary dry within an interval of five years of regeneration. Two hundred plots were established in the forest and two monitoring surveys were carried out, with interval of five years between them. All individuals in each plot with diameter at the ground level ≥ 3 cm were measured. After five years, no differences were observed in the number of species. Total density and mean basal area decreased, as a result of the maturation of the forest and possibly due to a prolonged drought in 2012. In 2008, the total basal area was 10.59 m².ha-1, increasing to 11.01 m².ha-1 in 2013. The mean height of the community did not increase significantly, from 3.59 m in 2008 to 3.65 min 2013. The number of individuals in the larger diameter classes reduced between 2008 and 2013, while the opposite was observed for smaller classes. Some structural parameters increased or decreased depending on the group of species analyzed and there was still a group that did not present significant changes. Therefore, age since abandonment can affect the regeneration process and the resilience of the forest. We realized, the speed in which these alterations occurred in an interval of five years can be considered slow and changes in the recovery process of a 16-year-old forest may not be detected.

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A caatinga é caracterizada por regiões áridas e semi-áridas devido a sua irregularidade de precipitação e caracterizada por longos períodos de estiagem. A investigação do banco de semente presente nessas regiões, além de nos dar informações sobre a flora atual, possibilita predizer um cenário futuro das comunidades vegetais diante de pressões antrópicas. Este trabalho tem por objetivo analisar comparativamente a densidade e a composição florística do banco de sementes acumuladas da estação seca provenientes de diferentes áreas de caatinga. Foram selecionadas 14 áreas de caatinga de acordo com grau de antropização, gradiente hídrico e diferentes intensidades de herbivoria nos munincípios de Floresta e Itacuruba, Pernambuco. Foram coletadas 5 amostras de serrapilheira, em 14 parcelas. O material foi levado para casa de vegetação da UFPE, dispostos diretamente em bandejas de isopor, com regas diárias e observado por 3 meses. Foi observado um pico de germinação nas primeiras 4 semanas para o material oriundo de todas as parcelas. Foram identificadas 44 morfoespécies de plântulas de gramíneas, herbáceas e arbóreas. A maior riquezade espécies germinadas foi de herbáceas, bem como as mais abundantes. Não houve diferença signifcativa entre riqueza de espécies e pressão de herbivoria segundo a análise de GLM, mas houve diferença significativa entre a densidade e pressão de herbivoria para todas as distâncias de cursos de água e a partir da análise de NMDL foi observado que só houve diferença significativa entre áreas com curso permanente de água e áreas sem um curso de água próximo (Rglobal = 0.155; p= 0,014).