Comparisons of agricultural and natural ecosystems reveal the magnitude of the effects of agricultural practices on the diversity and abundance of soil nematodes. Consequently, there is the need for testing ecological hypotheses, specifically with regard to nematode ecology, in natural and agricultural soils to seek strategies for biological control and environmental monitoring. We studied soil nematode assemblages and soil physical attributes of five soil layers (0-10, 10-20, 20-30, 30-40 and 40-50 cm) from sugarcane plantations and forest remnants in the sugarcane zone of Pernambuco State, Brazil. Structure and composition of the nematode assemblage and soil properties differed between forest and sugarcane soils, even in the same locality. The soil bulk density and the abundance of all nematodes and the diversity of plant-parasitic nematodes were greater whereas soil porosity, soil respiration and abundance of predator nematodes were smaller in sugarcane than in forest areas. We suggest that sugarcane management practices result in changes in the soil properties and concomitantly alter the composition and structure of the nematode assemblages. Co-inertia analysis indicated that others environmental factors also might be affecting the nematofauna.

Florística, classificação sucessional e síndromes de dispersão em um remanescente de Floresta Atlântica, Moreno-PE RESUMO O objetivo neste estudo foi avaliar a florística, a classificação sucessional e as síndromes de dispersão do componente arbóreo em remanescente de Floresta Ombrófila Densa. A área localiza-se no Engenho e Destilaria Dourado em Moreno -PE. Foram locadas 15 parcelas de 10 x 25 m para o componente adulto (CAP e" 15 cm) e 15 subparcelas de 1 x 25 para a regeneração (CAP < 15 cm e H > 1 m). Os indivíduos amostrados foram classificados em família, gênero e espécie, sendo as espécies classificadas quanto ao grupo sucessional (pioneiras, secundárias iniciais e secundárias tardias) e à síndrome de dispersão (anemocóricas, autocóricas e zoocóricas). Foram amostrados 444 indivíduos adultos e 407 regenerantes, pertencentes a 31 famílias, 47 gêneros e 76 espécies. As famílias com maior riqueza foram Mimosaceae, Melastomataceae e Myrtaceae. Este fragmento encontra-se em início de sucessão, pois 82% das espécies são pioneiras ou secundárias iniciais. A dispersão predominante foi a zoocórica. O conhecimento das espécies presentes nessas áreas, bem como o estádio de sucessão e a síndrome de dispersão, é de suma importância na elaboração de intervenções de conservação e restauração dessas áreas de Floresta Atlântica.Palavras-chave: Fragmentação de habitat, grupos ecológicos, componente arbóreo e regeneração natural. Floristics, successional classification and dispersion syndrome in an Atlantic Forest remnant, in Moreno, Pernambuco, Brazil ABSTRACTThe objective of this study was to evaluate the floristic, the successional classification and the dispersion syndromes of the arboreal component in an Atlantic Forest remnant. The area is located in Engenho e DestilariaDourado in Moreno, Pernambuco, Brazil. Fifteen plots of 10 x 25 m for the adult component (CBH e" 15 cm) and 15subplots of 1 x 25 m for the regeneration (CBH < 15 cm and H > 1 m) were located. The sampled individuals were classified into family, genus and specie, and the species classified for the succecional group (pioneers, early secondary and late secondary) and the dispersion syndrome (anemocorous, autochorous and zoochorous). Four hundred and forty-four adult individuals and 407 regenerants, belonging to 31 families, 47 genera and76 species, were sampled. The families with the highest species richness were Melastomataceae and Myrtaceae. This fragment is in early succession, since 82% of the species are pioneers or early secondary. The dispersion predominant was the zoochorous. The knowledge of the species presents in these areas, as well as the succession stage and the dispersion syndrome, is of utmost importance in the development of conservation and restoration intervention of these areas in the Atlantic Forest.

The aim of this study was to evaluate the phytosociological structure of an adult woody component in an Atlantic Forest fragment known as Mata da Onça, Municipality of Moreno -PE. Fifteen plots of 10 x 25 m were established, in three rows of five plots 25 m apart, while the rows were 50 m apart. The adult woody individuals with CBH (circumference at 1.30 m above ground level) ≥ 15 cm were identified to the species level, and the diameter and height were measured. 444 individuals belonging to 76 species were sampled, with an estimated density of 1,184 ind.

RESUMOO estudo foi realizado no fragmento florestal Mata da Onça, em Moreno, Pernambuco, com o objetivo de avaliar a estrutura fitossociológica da regeneração arbórea. Para obtenção dos dados foram demarcadas 15 parcelas de 1 x 25 m, alocadas em parcelas de 10 x 25 m já existentes no fragmento. As análises foram realizadas nos indivíduos com circunferência a 1,3 m do solo (CAP) maior ou igual a 15 cm e altura total (H) maior ou igual a 1 m, em que as alturas foram divididas em três classes: 1) 1,0 ≤ H ≤ 2,0 m; 2) 2,0 < H ≤ 3,0 m e 3) H > 3,0 m. Foram amostrados 407 indivíduos pertencentes a 56 espécies, com uma densidade de 10.853 ind ha -1 . As espécies de maior valor de importância foram: Cupania racemosa, Eschweilera ovata, Protium heptaphyllum, Miconia prasina, Siparuna guianensis, Anaxagorea dolichocarpa, Cordia nodosa, Erythroxylum citrifolium, Psychotria cf. carthagenensis e Inga thibaudiana. Já as espécies com maior valor de regeneração natural total foram Protium heptaphyllum, Eschweilera ovata e Cupania racemosa. As espécies que ocorreram nas três classes de regeneração têm maior potencial de fazer parte da futura composição da floresta. Palavras-chave: espécie arbórea, Floresta Atlântica, fragmentação Phytosociology of natural regeneration of a Dense ABSTRACTThe study was carried out in the forest fragment Mata da Onça in Moreno, Pernambuco, with the aim to evaluate the phytossociological structure of arboreal regeneration. To obtain data fifteen plots of 1 x 25 m were demarcated, these allocated in plots of 10 x 25 m existing in the fragment. The analyses were performed on individuals with CBH ≤ 15 cm and H > 1 m, where the heights were divided into three classes: 1) 1.0 ≤ H ≤ 2.0 m; 2) 2.0 < H ≤ 3.0 m and 3) H > 3.0 m. Four hundred and seven individuals were sampled, belonging to 56 species, with a density of 10,853 ind ha -1 . The species of greater value of importance were: Cupania racemosa, Eschweilera ovata, Protium heptaphyllum, Miconia prasina, Siparuna guianensis, Anaxagorea dolichocarpa, Cordia nodosa, Erythroxylum citrifolium, Psychotria cf. carthagenensis and Inga thibaudiana. Species with greater value of total natural regeneration were Protium heptaphyllum, Eschweilera ovata and Cupania racemosa. The species which occurred in the three classes of regeneration have greater potential to be part of the future composition of the forest.

Nematodes present high potential as a biological indicator of soil quality. In this work, it was evaluated relations between soil physical properties and nematode community under sugarcane cropping and remaining of Atlantic Forest areas in Northeastern Pernambuco, Brazil. Soil samples were collected from September to November 2009 along two 200-m transects in both remaining of Atlantic Forest and sugarcane field at deeps of 0-10, 10-20, 20-30, 30-40, and 40-50 cm. For soil characterization, it was carried out analysis of soil size, water content, total porosity, bulk density, and particle density. The level of soil mechanical resistance was evaluated through a digital penetrometer. Nematodes were extracted per 300 cm(3) of soil through centrifugal flotation in sucrose being quantified, classified according trophic habit, and identified in level of genus or family. Data were analyzed using Pearson correlation at 5% of probability. Geostatistical analysis showed that the penetration resistance, water content, total porosity, and bulk density on both forest and cultivated area exhibited spatial dependence at the sampled scale, and their experimental semivariograms were fitted to spherical and exponential models. In forest area, the ectoparasites and free-living nematodes exhibited spherical model. In sugarcane field, the soil nematodes exhibited pure nugget effect. Pratylenchus sp. and Helicotylenchus sp. were prevalent in sugarcane field, but in forest, there was prevalence of Dorylaimidae and Rhabditidae. Total amount of nematode did not differ between environments; however, community trophic structure in forest presented prevalence of free-living nematodes: omnivores followed by bacterial-feeding soil nematodes, while plant-feeding nematodes were prevalent in sugarcane field. The nematode diversity was higher in the remaining of Atlantic Forest. However, the soil mechanical resistance was higher under sugarcane cropping, affecting more directly the free-living nematodes; especially Dorylaimidae which was the most sensible to changes in soil physical properties.