Quantitative assessment of the governing factors of the long-term dynamics of geographically isolated wetlands: A case study within the Nenjiang River Basin, Northeast China

Abstract

Geographically isolated wetlands (GIWs) provide a portfolio of ecosystem services and contribute largely to landscape functions. Several studies have found that increasing pressure induced by climate change and anthropogenic activities on wetlands ecosystems have been significant around the world. Yet few studies have quantified the impact of natural changes and anthropogenic activities on GIWs. This paper introduces the assessment of the spatiotemporal dynamics of GIWs in the downstream portion of the Nenjiang River Basin, Northeast China. The contribution of anthropogenic activities and natural change were quantitatively evaluated for different periods over the past 38 years (1978–2015). Using a five-stage wetland dataset and four-stage land use datasets, we found that 86% of the GIWs in the study area had disappeared and mainly been replaced by unused land (28.39%) and farmland (54.90%). Anthropogenic activities were deemed responsible for this remarkable loss of wetlands from 1978 to 2008, while in recent years naturally-induced changes contributed more to the decrease of GIWs. Given the current warming and drying trends in the regional climate, efforts should be made to conserve and restore GIWs in order to foster wetland services for a multitude of beneficiaries.