地理漫步·世界地理英语30篇（3）

14 / 30

温哥华岛：海洋与雨林之间的生物地理过渡带

Vancouver Island lies off Canada’s Pacific coast, separated from mainland British Columbia by the Strait of Georgia.
Its western shores face the open Pacific, absorbing moisture-laden westerlies that fuel temperate rainforests.
The island’s mountain spine forces air upward, causing orographic rainfall exceeding 3,000 mm per year on the west coast.
Eastward, rain shadows reduce annual precipitation to under 1,000 mm, supporting drier Garry oak ecosystems.
This sharp moisture gradient creates one of North America’s steepest biogeographic transitions over just 100 km.
Marine fog sustains epiphytic mosses and lichens even where rainfall diminishes seasonally.
Glacial valleys carved deep fjords, while post-glacial rebound continues lifting coastal terraces at measurable rates.
Salmon migration corridors link marine nutrients to forest soils, illustrating cross-ecosystem material flow.
Indigenous land-use patterns historically mirrored these spatial gradients through seasonal resource harvesting.
Today, climate-driven shifts in storm tracks threaten to widen the rain shadow and compress coastal habitats.