Does someone have an explanation for the pattern seen in the pictures
joined to this ?
These were taken in Québec's boreal forest (52° north). Along the gravel
roads, on sand, Niphotrichum canescens form regular carpet for km and
km, broken only by accidents, for instance moose tracks or small
landslide. In 2 separate area separate by a few km, the patterns shown
on the picture were observed.
The rings are formed by alternating row of dead and living mosses. The
innermost dark ring is obviously the older. These dead ring are
progessively younger toward the outside of the pattern, as can be seen
by the various shade of brown. In some case, the ring are almost
perfectly circular, in others they are wavy. Pattern of all age were
observed, younger one formed only by a spot or one circle, older having
many circles. I have no idea of the time frame involved, as I made only
one visit. Vascular plants appears not to be affected. The machinery
tracks gives a scale.
I speculate that it might be a fungi, for no better reason that the
circular pattern reminds me of the «witch circles» of the (delicious)
mushroom growing in my lawn. But then the effect is inversed, as death
is involved instead of the blooming effect on my grass. Or what ? Virus ?
Has this been studied and described in a paper ? This is the first time
I encounter it. Is it frequent ?