CAM a cloud forest advantage?

[Derrick]

I have placed this under a cultivation heading because it provides hints toward best cultivation practices for pertinent species.

CAM a Cloud Forest Advantage.

Although bromeliads are common in montane forests they are rarer components of seasonally or perpetually sodden, high altitude, tropical cloud forests.  It is hypothesized that having rain, fog or dew persistently coating the heavily trichomed leaves so typical of CAM bromeliads, inhibits their essential gas exchanges sufficiently to suffocate them.  Yet, a study within the Cerro Jefe cloud forest in Chagres National Park, of Central Panama, compared the growth of C3 and CAM bromeliad species. Here altitudes range from 300-1000 m. (984-3281 ft.) with annual rainfalls of approximately 4 m. (13 ft.)  Researchers found that facultative CAM plants actually grew better than C3 plants throughout this region’s saturated wet seasons possibly because of their ability to exchange essential gasses either day or night according to suitable weather phases.  The inability of C3 plants to store CO², limits their usable gas uptakes to daylight; furthermore, during dry seasons, the water use efficiency of the CAM pathway gives another most obvious advantage.  Hence, CAM in its facultative form provides a far more flexible pathway than C3.  (Pierce et al. 2002.)

It has been hypothesized that CAM bromeliads inhabiting such particularly wet areas have developed special strategies better able to cope with long sodden periods but I am not aware of any studies that detail this. 

However, the low numbers of CAM bromeliad species at Cerro Jefe does support the probability of a recent evolutionary radiation of this photosynthetic pathway into cloud forests. (Pierce et al. 2002.)  Yet where does Brocchinioideae fit in this scenario?