It seems as though Ghost Orchids have had a rough go the last century. I have talked with many ‘old timers’ who all told me Ghost Orchids used to be much more numerous than they are today but were never common. I heard one story of the vast majority of hundreds of Ghost Orchids dying from a freeze during the late 1970s. While you may think that this freeze was a totally normal event and nature was just taking its course this is not entirely accurate. You see, the digging of canals and draining of water from the majority of South Florida caused the water in much of the Ghost Orchid habitats to be lowered. During natural freeze events the water gives off heat to shelter the Ghost Orchids from the frost. I have measured the temperature difference to be about 2.5º C higher in the middle of a water filled swamp (at ~5 feet above ground) than the outside during a freeze in January of 2008 in Big Cypress Nation Preserve. This heat shield has historically kept Ghost Orchids safe. When the decision was made to lower water levels in South Florida I believe this was the main reason why Ghost Orchids are much less common today than in the past. The low water levels left the Ghost Orchids vulnerable to freeze events and thousands of Ghost Orchids have died as a result.
It is also interesting to note that at the Miami International Airport (MIA) most of the overnight freezes since the late 40s were in the 1970s and 80s. I put together a graph of the low temperatures recorded at MIA from the late 1940s to 2007. This graph can be seen here. The freeze of 197 is a historic freeze both for Ghost Orchid temperatures and snow fall. The freeze of 1977 is known to kill many Ghost Orchids and also to bring snow to both Miami and the Bahamas.
Throughout the majority of the 20th century orchid collecting was a popular legal activity which has since been banned. Many orchids including the cigar (Cyrtopodium punctatum) and mule-ear (Oncidium luridum) orchids were once a common plant, but the rampant collecting of these orchids has left them as a rarity in South Florida these days. Some Ghost Orchids were no doubt legally taken during this time period which contributed to their relatively low numbers today.
Fakahatchee Strand State Preserve has long been considered the Ghost Orchid capital of the world. Fakahatchee Strand is a mysterious and wonderful place which still holds many secrets. During the 1940s and 50s bald cypress wood was highly prized because it is rot resistant and will last longer than most woods. Fakahatchee Strand’s bald cypress trees were devastated during this time frame. An extensive system of trams on which trains ran was set up across much of Fakahatchee Strand’s 85,000 acres. The larger cypress trees were cut by hand and then hauled out using the trains, devastating everything in their path. This logging left the Fakahatchee with very few virgin cypress trees and changed the landscape drastically in the strand. Orchids that were not taken by collectors, killed by logs or building of trams, were now exposed to higher levels of sunlight, from the loss of canopy, than they may have been able to handle.
The trains and tracks are gone today along with the cypress trees, but the trams still remain. Janes Scenic Drive runs through the heart of Fakahatchee along one of the old trams. The majority of trams are now too overgrown to even walk on, but some still have roads and/or hiking trails which give the public access to this wonderful area. While most of the public which visits Fakahatchee is respectfully of the current laws to protect the natural resources the preserve holds, Ghost Orchids are still poached. This is a shame since Ghost Orchids removed from the wild are almost certainly doomed for a quick death because of their difficulty of care.
The Ghost Orchid is pollinated by the Giant Sphinx Moth (Cocytius antaeus). This moth is rare itself, and the Ghost Orchid is no doubt dependant upon the Giant Sphinx Moth to continue its life cycle. Very little is known about the moth’s populations, but another possibility contributing to the decline in Ghost Orchids is a decline in the Giant Sphinx Moth population.