Arthropod diversity in rice crop in the rotation system with pastures

Doctoral thesis abstract

Abstract

Rice is one of the main exporting items in Uruguay with a valuation for the quality and safety of the product. Crops remain flooded for a large part of its development period, so that can be considered as seasonal aquatic ecosystems. It is based on a production system in rotation with pastures and alternative crops, integrated with livestock production, and has the challenge of developing indicators for productive, economic and environmental sustainability quantification. Agricultural activity is associated with poor diversity areas, there are certain agro-ecosystems such as rice crop, that sustain high levels of biodiversity. However, the complex community of living organisms present in the crop plays a role that is generally not evident until its structure is affected. Information on biodiversity in the agro-ecosystem of rice cultivation in Uruguay is incomplete. The objective of this work was to characterize the diversity of insects and spiders in the cultivation of rice and nearby natural areas, in the rotation system with pastures. The record of new reports of insect and spider species for the country is highlighted, and there are still species to report. The exploratory sampling showed greater abundance and richness of insects in the patches of native vegetation (riverine forest), in comparison with the rice cultivation, demonstrating the importance of these areas as species reservoirs. More morphospecies were recorded in pastures than in rice crops, in samplings with pitfall traps. In the study of the composition of spider species between the pasture, patch of native vegetation and rice at tillering stage, the greatest abundance of exclusive species was recorded in the pasture. On the other hand, in the sampling of aquatic arthropods, richness values were greater than those recorded in crops of organic rice production in Costa Rica, Italy and Australia. Richness and diversity of arthropod species observed in this work could positionate rice cultivation as a production system with the potential to contribute to the conservation of these groups, and produce in a sustainable way, through the definition of management measures that allow the conservation of the observed biodiversity.