Archipelagic landscape patterns and their ecological effects in multiple scales

An archipelago is a unique geographic complex with distinct vulnerability to disturbances in coastal areas. The natural features, increasing human activities and their spatial heterogeneities in the archipelago result in complex landscape patterns and ecological effects, which makes the archipelago natural laboratory for landscape ecology study in multiple scales. The particular spatial scales of landscape, island and grid were followed to reveal the comprehensive status, influencing factors and ecological effects of archipelagic landscape patterns, and the Miaodao Archipelago in North China was selected as the study area. Landscape pattern indices (LPIs) in different scales were analysed based on field investigation and geographic information system. Ecological response indicators (ERIs) responding to archipelagic landscape patterns were identified and the relationships between LPIs and ERIs, including land surface temperature (LST), net primary productivity (NPP), plant diversity and soil property, were discussed. Results indicated that plantation, grassland and building land occupied the largest areas in the landscape scale and ERIs significantly differed among different landscape types. In the island scale, some of LPIs regularly changed with the changes in island area, distance to the mainland, population and GDP, yet ERIs were generally insensitive to landscape pattern. In the grid scale, LPIs showed distinct spatial heterogeneities and were affected by altitude and slope; LST, NPP and soil fertility were affected by landscape types, fragmentation, edge effect and shape complexity, whereas plant diversity and soil moisture were mainly influenced by landscape types. The landscape patterns exhibited specific characteristics in different scales, and their ecological effects were closely related to the scales. Island area, distance to the mainland, terrain and human activity were fundamental, the most relevant, limiting and main driving factors of archipelagic landscape patterns, respectively.