Different driving mechanisms of spatial heterogeneity at the community and landscape levels in the wetland ecosystem dominated by hydro-ecological processes

The analysis of wetland patterns and their driving mechanisms is the research focus of discussion in wetland ecology. In this study, we tried to analyse the spatial differentiation patterns of community and landscape levels dominated by hydro-ecological processes. The spatial differentiation patterns of landscape patterns and their driving mechanisms were explored in focus. This study was based on 30-year land cover data of Baiyangdian Wetland Nature Reserve in North China Plain, China, constructing an ecological response relationship matrix between inundation frequency and vegetation cover frequency for the spatial divide at the community and landscape level. By constructing a landscape index set and analysing the index set using clustering, non-metric multidimensional scale analysis, discriminant and redundancy analysis, we finally obtained the differentiation characteristics of wetland landscape patterns and their driving mechanisms. The spatial differentiation of community levels along the water level gradient showed a banded distribution pattern of submerged-floating-emerge to meadow shrubs, but the stability of the hydrological regime dominated the spatial differentiation of landscape levels. Wetland landscapes along the stability gradient of the hydrological regime were divided into stable and fluctuating zones. The stable zone had the landscape pattern characteristics of low fragmentation, simple and regular shape and high numbers of different patch types; the landscape pattern of the fluctuating zone was characterized by a high fragmentation and complex shape, with a small number of different patch types and a non-uniform distribution. The analysis of the driving mechanism showed that the stability of the hydrological regime was the only reason for the formation of the landscape pattern of the stable zone. The combined effect of human-dominated and natural-supplemented effects jointly drove the formation of the landscape pattern of the fluctuating zone. The influence of human on the landscape pattern of the fluctuating zone showed a trend of spatial expansion from high areas to shallow water areas. The combination of traditional landscape indices and aquatic ecological processes characterized the spatial differentiation of wetland landscape patterns, and also verified the feasibility of this method. This study was a successful example of conducting ecological process-oriented landscape level spatial differentiation analysis. The results of the study are intended to provide recommendations for the rational and effective use and precise conservation of wetland plant and animal resources and the restoration of wetland ecosystems.