Scale effect of coastal landscape pattern stability and driving forces:a case study of Guangdong Province,China

The long-term dynamic evolution and underlying mechanisms of coastal landscape pattern stability,driven by strong anthropogenic interference and consequently climate change,are topics of major interest in national and international scientific research.Guangdong Province,located in southeastern China,has been undergoing rapid urbanization over several decades.In this study,we quantitatively determined the scale threshold characteristics of coastal landscape pattern stability in Guangdong Province,from the dual perspective of spatial heterogeneity and spatial autocorrelation.An analysis of the spatiotemporal evolution of the coastal landscape was conducted after the optical scale was determined.Then,we applied the geodetector statistical method to quantitatively explore the mechanisms underlying coastal landscape pattern stability.Based on the inflection point of landscape metrics and the maximum value of the MoranⅠindex,the optimal scale for analyzing coastal landscape pattern stability in Guangdong Province was 240 m×240 m.Within the past several decades,coastal landscape pattern stability increased slightly and then decreased,with a turning point around 2005.The most significant variations in coastal landscape pattern stability were observed in the transition zone of rural-urban expansion.A q-statistics analysis showed that the explanatory power of paired factors was greater than that of a single driving factor;the paired factors with the greatest impact on coastal landscape pattern stability in Guangdong Province were the change in gross industrial output and change in average annual precipitation from 2010 to 2015,based on a q value of 0.604.These results will contribute to future efforts to achieve sustainable coastal development and provide a scientific basis and technical support for the rational planning and utilization of resources in large estuarine areas,including marine disaster prevention and seawall ecological restoration.

The Fiji Tide-Gauge Stations

We analyse the location, stability and continuity of the two tide-gauge stations in Fiji. Both stations are awkwardly placed on heavy harbour constructions resting on soft sediments susceptible to serious compaction problems. The nearby GPS stations resting on a bedrock hill offer no solution to the stability problems. The Suva tide-gauge has been moved three times, and must accordingly be analysed in segments. Even the last location covering years 1989 to 2917 provides a mixed picture of 16 years of stability, 10 years of rapid rise, and 4 years of rapid fall in relative sea level. This suggests the interaction of subsidence and cyclic changes in sea level. Any application of mean trends would produce meaningless values rather misguiding than assisting in the handling of estimation of on-going absolute sea level changes. We find this vital for the discussions of local sea level changes to be held at the UN conference on “Our Oceans, Our Future” in June in New York and at the main COP23 conference in November in Bonn.