[3] The Fraser fir and red spruce, which are Ice Age relics, dominate the forests that grow on these summits.

[4] The resulting thinning of the forest canopy leads to the drying of the moss mats that are essential for the spider's survival, as it requires climates of high and constant humidity.

[6] M. montivaga can take as long as three years to reach maturity, due to low temperatures and resulting slow metabolism.

The widespread death of Fraser fir trees has destroyed many habitats for M. montivaga, and the spider species was listed as endangered in 1995.

Many Fraser firs have died due to infestation with Adelges piceae, the balsam woolly adelgid, an insect pest introduced from Europe.