Estudo da fauna de artropodes associada a plantas invasoras em agroecossistemas organicos e convencionais

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The model of agriculture knoWIl as conventional management, that relies on monocultures and intensive use of sinthetic chemical inputs, brings several damages to human health, natural resources and biodiversity. In the last decades, many altemative agricultural managements have been developed as answers to the chalenge of food production with time and space sustainability. These management types incorporate many techniques that promote and increase agroecosystems biodiversity. One of them is to maintain weed at the edges of cultivated fields. Weed is seen in different ways it has a controvertial role in different agroecosystems. The most widespread vision focuses on its pest status: weed compete with the crops and maintain pest insects populations. However, weed can benefit agroecosystems in many ways: it maintain soil humidity and structure, and may provide shelter and other resources to benefical arthropods. The aim ofthis study is to analyse the arthropod communities associated with weed in organic and conventional agroecosystems.The main questions are: 1) how structured are these arthropod communities, in terms of diversity, similiraty and organizacional structure of guilds? 2) can management influence the composition of those communities? 3) are there taxonomic groups useful as bioindiocator for these communities? 4) is there any difference in incidence of pest arthropod associated with weed in these agroecosystems? F our commercial horticulture agroecosystems were surveyed in São Roque/SP region. Two areas were located on a hill slope and two were situated in a fiat area. In both relieves a pair of conventional-organic management agroecosystems were sampled for arthropods associated with the weeds. The arthropods were sampled monthly between September 1996 and August 1997 by visual inspection and sweep, fixed and identified at 1east morphospecies. Diversity and similarity were analyzed by Morisita and Shannon- Wienner indexes, respectively. Guilds were determined by food habits information available in the literature. Management and relief influence was analyzed by PCA. Bioindicator taxonomic groups and the incidence of pest arthropods were analyzed by chi-square. In both relieves, organic agroecosystems had communities richer and more diverse than the conventional agroecosystems. There is no clear1y defined pattem of communities similarity between communities. Although different in richness, diversity and species assemblage, these four communities showed considerable resemblance in organizational guild structure. Management type had striking influence on the community composition. It was not possible to propose a taxonomic group as reliable bioindicator for these communities. The incidence of pest in the organic agroecosystems was lower or at most similar to the incidence in conventional agroecosystems

ASSUNTO(S)

artropode comunidade entomologia

ACESSO AO ARTIGO

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