地理漫步·世界地理英语30篇（6）

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海平面上升背景下红树林–盐沼生态交错带的迁移速率

Where mangroves meet salt marshes along temperate coasts, sea-level rise forces landward migration at variable speeds.
Mangrove seedlings establish fastest where tidal creeks provide sediment delivery and salinity buffering.
Salt marshes retreat slower because their rhizomes stabilize soil better than pneumatophores in low-energy bays.
Lidar elevation models show marsh platforms gain elevation at 2.1 mm/yr, mangroves at 4.7 mm/yr—both below current SLR rates.
Inlets with strong tidal exchange accelerate mangrove expansion by flushing sulfide toxins from marsh soils.
However, seawalls block migration entirely, converting ecotones into abrupt, lifeless boundaries.
Soil carbon inventories differ sharply: mangrove peat stores twice the carbon per hectare as marsh sod.
Monitoring transects reveal ecotone width narrows by 8 meters annually where hard infrastructure limits space.
Migration success depends less on species traits than on sediment supply and coastal geomorphic openness.
These zones are not static borders but dynamic frontiers reshaped by hydrodynamics and human barriers.