Search

Zoigê Plateau, China's largest plateau marsh wetland, has experienced large-scale degradation of the marsh wetland and evolution of the wetland landscape pattern over the past 40 years due to climate warming and human activities. How exactly do the wetland landscape pattern characteristics change? How do climatic change and human activities affect the wetland evolution? These questions are yet to be systematically investigated. In order to investigate changes to the marsh wetland on the Zoigê Plateau, field investigations, spatial and statistical analysis were undertaken. Findings from our study indicate that from 1977-2016, the area of marsh wetland on the Plateau reduced by 56.54%, approximately 66,700 hm² of marsh wetland has been lost. The centroids of both marsh and marshy meadow migrated and the landscape centroid migration behaviors were also correlated with the distribution and variation of the marsh wetland on different slopes. In addition, the number of marsh landscape patches initially increased before decreasing; the number of marshy meadow landscape patches also recorded an initial increase, followed by a decline before a final increase. As the effects of human activities weakened, the aggregation degrees of both marsh and marshy meadow increased. Overall, the fragmentation degree, diversity and fractal dimension of the marsh wetland all declined. An investigation into the driving factors affecting the Plateau area shows that the increase of annual average temperature was the natural factor while trenching and overgrazing were the main human factors resulting in wetland degradation. Results from this study provide basic data and theoretical foundation for the protection and restoration of marsh wetland in alpine regions. [ABSTRACT FROM AUTHOR]

[Display omitted] • This is nearly 40 years of time field monitoring of changes in the distribution of Siberian cranes at staging stopover sites in the Momoge Reserve. • The spatial distribution of Siberian cranes at staging grounds under human and climatic disturbances migrates in response to spatial changes in the water body. • Siberian cranes are more sensitive to changes in water fragmentation at staging areas. • Neither too fragmented nor too aggregated water bodies are suitable migratory resting habitat features for Siberian cranes. The Siberian crane (Grus leucogeranus), a critically endangered species, is used as an indicator species for ecosystem stability because of its sensitivity to the environment. The distribution of Siberian cranes has shown dramatic fluctuations on an order of magnitude at the main stopover site (Jilin Momoge National Nature Reserve) since the present century, which poses a great challenge to the conservation of endangered species. Research on the threshold values of key factors of the Siberian crane in stopover habitats and the relationship between the Siberian crane and hydrological temporal and spatial fluctuations can promote endangered species conservation. The response of population changes and distribution patterns of Siberian cranes to hydrological temporal and spatial patterns of wetlands was analyzed from 1984 to 2020. The results showed that population changes and distribution patterns of Siberian cranes were highly correlated with hydrological temporal and spatial patterns in the study area, and their variation trend was the same. However, there were obvious stage migration changes in the core activity area of the Siberian crane (1984–2000, 2001–2010 and 2010–2020). The habitat characteristics of fragmentation, dispersion and complex shape of water bodies changed from steady to dramatic fluctuations and then leveled off in the core activity area of Siberian cranes during the 37 years of migration transit. This was closely related to the early agricultural reclamation and the later ecological water replenishment project in the study area. In addition, the trend of the water pattern index of the spatial distribution of Siberian crane active habitat was also closely related to their habitat selection preference. When the perimeter area fractal dimension of water (1.27–1.40), landscape division index (0.73–0.95) and aggregation index (80.97–91.36) are within a certain stable threshold, the stopover habitat of the Siberian crane is suitable. This study will provide scientific guidance for the conservation of the Siberian crane population and the development of wetland restoration projects. [ABSTRACT FROM AUTHOR]