Aspectos ecológicos e influência de Artocarpus heterophyllus Lam. na estrutura do componente arbóreo de fragmento florestal urbano, Recife - PE

Abstract

Known invasive in tropical countries, and jackfruit (Artocarpus heterophyllus Lam.) Is a large tree species, originating in southern India, introduced in Brazil in the midseventeenth century. In the forest fragment of the Botanical Garden of Recife (BGR), has attracted attention of researchers by the number of individuals and interaction with the local wildlife that assists in their dispersion, reducing the richness and diversity of native species. In the face of commitments made in the Biological Diversity Convention, signatory countries, like Brazil, have expanded studies on the behavior of exotic species outside their environment, in order to trace control and eradication strategies. In this perspective, this study aimed to know the population and age structure, spatial distribution, ecological characteristics of jackfruit (phenology, fruit and seeds biometrics, germination, allelopathy and toxicity), and the influence on the tree component structure, in order to support the management plan for the species in the forest fragment of BGR. It was conducted census of A. heterophyllus throughout the forest fragment and individuals classified as juveniles, pre-reproductive and adults, mapped with the use of ArcGIS software. In the evaluation of influence on the tree component structure held phytosociological survey, by the method of quadrants. The phenology was monitored every two weeks at 20 headquarters for 16 months and prepared dendrofenogramas. The biometric parameters of fruits and seeds were estimated, and number of seeds per fruit. In forest nursery was held influence test seed size (small, medium and large) on the germination and seedling development, and the results of averages compared by Tukey test at 5% probability. Experiments were also conducted in the laboratory evaluating allelopathy on seed Lactuca sativa L. and toxicity on microcrustacean Artemia salina Leach with aqueous extract of fresh leaves of jackfruit at concentrations of 0%, 1%, 3%, 5%, 10 % and 30%. The population of A. heterophyllus mapped was 445 trees, with structure in inverted "J" and aggregated spatial distribution. In the structure of the tree component were identified 51 species, and the higher value of importance: Thyrsodium spruceanum, A. heterophyllus and Brosimum discolor. Flowering and fruiting species were constant, with peaks in dry months. Biometrics fruits showed a high coefficient of variation (CV). Already biometrics seed showed lower CV, and there is, thus, influence the size of the seed germination and seedling vigor of A. heterophyllus. Allelopathy and toxicity of the species were proven, with negative influence of the aqueous extract already in the lowest concentration used (1%). Given the large population of the exotic in the area, their constant fruit production and possible genetic variability and the influence on the tree community, it can be said that jackfruit should already be considered invasive species in urban fragment of the Botanical Garden of Recife and deserves attention especially for the preparation of management plan aiming to control it.