Avian community structure and diversity in two intensively mono-cultivated agricultural fields

摘要

The enormity of the impact of human activity on biodiversity has been documented by many researchers. There have been numerous studies on the effects of local-scale changes in land use (e.g. intensive mono-culture agricultural practice) on the abundance and diversity of groups of organisms, especially aves. This changing pattern of land use, associated with the appropriation of increasing proportions of net primary productivity by the human population, seem not only to have reduced the diversity of life, but also to have reduced the carrying capacity of the environment in terms of the numbers of other organisms that it can sustain. Here, we estimate the size and diversity of the existing bird population in two different intensively mono-cultivated agricultural crops and then make an approximation as to how much this has been modified as a consequence of land-use changes shaped by human activities. It was observed in the present study that not only the population size decreased but also the diversity of the avian community in these agricultural fields decreased over a period of time. Dominance by a single species in these crops not only suggests the decrease in the diversity but also indicates that the dominant species has become a functional cereal crop pest.