Domestication of rice reshaped associated biodiversity of rice field ecosytem

The domestication of rice (Oryza sativa L.) has a rich history with its diversification from wild progenitors based on genetic differences. For human benefit, natural environments have been agriculturally modified. Concurrently, the biodiversity of natural or wild environments is greatly affected. Here, a comparison has been made between the biodiversity associated with wild-type rice and domesticated rice fields. Species were categorized into broad groups, i.e. Arthropoda (Arth), Other Invertebrate (OInv), Vertebrate (Vert), Algae (Alg), Fungi (Fng), Pteridophyta (Ptrd), and Higher Plant (HPlan). Physico-chemical factors including water depth (WD), water pH (pH), temperature (T), total hardness (TH), dissolved organic carbon (DOC), turbidity (Turb), and dissolved oxygen (DO) were measured directly in the field. Statistical analysis such as Student’s t-test, Kolmogorov-Smirnov test for equal distributions, tests for dominance and multiple indices including Simpson, Shannon, and Evenness were used to assess the biodiversity. Furthermore, Principal Component Analysis (PCA) and Multivariate Analysis of Variance (MANOVA) were used for community comparisons, and SIMPER analysis was used to assess dissimilarity between taxa. The Artificial Neural Network model (ANN) was applied to assess the relative importance of factors governing the system. The present study showed the assemblage of species in the wild along with domestication. The vertebrate species number was well correlated with all the other biotic groups indicating a bottom-up controlling pattern in the rice field ecosystem. The ANN analysis showed that of the environmental factors examined, WD played the most important role followed by pH, T, DOC, and DO as the next most influential factors in distinguishing wild and domesticated rice field ecosystems. SIMPER analysis demonstrated that arthropods were a major contributor to dissimilarity. Collectively our results showed that the domestication of rice led to a decline in biodiversity.