SURVEY ON HIGHER PLANTS' BIODIVERSITY IN MODELS OF RICE-SHRIMP ROTATION AND SHRIMP MONOCULTURE IN HOA TU AND NGOC TO COMMUNES , CAN THO CITY

Abstract

The study was conducted to assess the biodiversity of higher plants (macrophyte) between two models of rice - shrimp rotation and shrimp monoculture in Hoa Tu and Ngoc To communes, Can Tho city. Through the collection of plant samples in the dry season (at the beginning of shrimp crop, end of March 2024 in lunar calendar, April 2024 in solar calendar) and rainy season (at the end of shrimp crop, June 2024 in lunar calendar, July 2024 in solar calendar), biological indices such as diversity index (H’), equilibrium index (E), richness index (D), dominance index (Cd) and species similarity index (SI) were calculated and compared. The study was recorded a total of 83 plant species belonging to 39 families present in the survey area. Of which, the rice-shrimp model has 68 species, higher than 57 species in the mono shrimp model. The species composition in the rice - shrimp model was richer. The average diversity index (H') in the rice-shrimp model (2.50) was higher than that in the mono shrimp model (2.27); the balance index (E) and the richness index (D) of rice - shrimp were also higher (E = 0.63; D = 0.86) than in the mono shrimp model (E = 0.59; D = 0.84). At the same time, the dominance index (Cd) in the rice - shrimp model (0.15) was lower than that in the mono shrimp model (0.17), reflecting a stable species structure and not dominated by a few dominant species. In particular, the similarity index (SI) between the two models was 67.2%, showing that a large proportion of plant species are common species, despite the different farming conditions of the two models was recorded. The results showed that the rice - shrimp model had a higher level of biodiversity than the shrimp monoculture model, which may be related to the characteristics of integrated farming and environmental conditions less affected by agricultural chemicals. From the results of this study, it provides a scientific basis to propose solutions to conserve biodiversity in agricultural cultivation systems, contributing to the protection of biological resources and ensuring long-term livelihoods for farmers in coastal areas of the Mekong delta.