Mite Species Differ Greatly Among Habitats

Various species of mites specialize in where and when they colonize dead tree needles.

Which mites are present depends upon whether the leaf litter hangs from a tree branch or lies on the ground, how long the litter has been decomposing, and the site's elevation and location.

Most of the 129 mite species found on amabilis fir needles from two northern Vancouver Island mountains prefer either canopy or ground habitat, although only 15 common species are confined to one of these locations. Ground litter supports eight times more mites and five times more species than litter suspended in trees. At both locations, a procession of mite species occupies the litter during a year of decaying.

While the make-up of mites varies considerably among individual trees within a stand, patterns based on elevation do exist. Most canopy mites adapt to elevations ranging from 800 to 1200 m. Ground-based mite species are more prone to thriving at specific elevations within that range. Overall, these invertebrates become less abundant at higher elevations.

Adding to the complexity, mites living on one mountain are not at all indicative of the species living just 14 km away. Only one-third of canopy species and half of ground species were collected from both Mt. Cain and Mt. Maquilla.