Twenty years of agricultural expansion drives the trophic structure changes of a primary consumer in an important Brazilian farming production basin
摘要
Seeking to evaluate the impact of the increasing conversion of forest remnants into agricultural areas on the aquatic food chain, the present study investigated land use at multiple spatial scales and its impact on primary producers and primary consumers in a Neotropical floodplain, using δ13C and δ15N in three periods within a 20-year window. Over years of study, an increase in the percentage of agricultural land use in the investigated area was verified. The δ15N values of primary producers were associated with impacts in the riparian forest and the basin. In contrast, the increase in the δ15N values of the consumer was related to impacts in the basin. Changes in consumer’s trophic position and isotopic niche reflected the impacts on the reduction in riparian forests in rivers. In contrast, the most conserved area of riparian forest tends to be a barrier to the impacts of land use on the basin, as observed in the river in the protected area. Thus, the conservation of riparian forests is essential for the stability of the trophic structure of aquatic consumers, as it acts as a barrier to impacts on the basin.