地理漫步·世界地理英语30篇（6）

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生态系统崩溃的空间阈值：当破碎化切断连通性

Wildlife corridors must exceed minimum width to support seasonal migration of large mammals.
Roads narrower than 50 meters still permit small mammal movement but block amphibians completely.
Island biogeography theory predicts species loss when habitat patches fall below critical area.
River damming fragments aquatic gene flow, reducing genetic diversity downstream over decades.
Wind-dispersed plant seeds fail to cross gaps wider than 300 meters in arid zones.
Satellite data reveal forest fragmentation accelerates once canopy cover drops below 40%.
Urban sprawl creates 'ecological deserts' where pollinators cannot travel between flowering patches.
Marine protected areas lose effectiveness if buffer zones shrink below 12-kilometer coastal widths.
Thresholds vary by biome, yet all reflect how space constrains biological process rates.
Mapping connectivity loss helps prioritize landscape restoration where spatial thresholds remain intact.