Arboreal Biodiversity Across Spatial Scales Project (A.B.A.S.S.)  2006 - 2012
Walbran Valley Canopy Project  2004 – 2008

Biodiversity in Coastal Temperate Rainforests

Worldwide, coastal temperate rainforests are rare; originally covering less than 1% of the Earth’s land surface, they accumulate and store more organic matter than any other forest type. The coastal temperate rainforest on the west coast of North America also contain the tallest trees in the world. High up in the canopy of these trees, mosses, lichens and other epiphytes create habitat for a myriad of understudied invertebrate groups.

In 2004 we initiated a series of investigations into the factors which structure arboreal (canopy) and terrestrial (forest floor) invertebrate assemblages.  These studies revealed high biodiversity among the acarine suborder Oribatida (a.k.a. oribatid mites); many of which are undescribed and new to science. Additionally, many oribatid mite species occurring in the canopy are not found on the forest floor, and most species within these forest are limited in their distribution to North American coastal temperate rainforests.

The factors which shape canopy oribatid mite communities are related to habitat availability, moisture limitation and random dispersal events of individual species. Our results suggest dispersal limitation associated with physical tree-to-tree dispersal barriers at small spatial scales, but stochastic long-distance dispersal events associated with wind and passive aerial vectors contribute to the maintenance of biodiversity at larger spatial scales. High biodiversity on the forest floor is attributed to high habitat heterogeneity in these systems.

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