The following information(or reports) and photos were sent to me by Paul-san (Paul Temple), who has been a good friend of mine since I joined the cp-listserve in 1994.
The photos are provided with Paul-san's goodwill. The copyright of the photos belongs to Mr. Paul Temple.
An Expedition to see Pinguicula Casabitoana in habitat, with related comments
On June 23, 2011, I was priveledged to be able to revisit Mount Casabito in the Dominican Republic, primarily to try to see Pinguicula casabitoana.
The peak of Casabito is protected as a National park, named the Reserva Científica Ébano Verde (the Green Ebony Scientific Reserve). This comprises 23.1 square kilometers (8.92 square miles) of terrain, about half of which is at sufficient altitude, reaching 1222 meters (4012 feet), to be cloud forest. The park is a treasure trove of endemic species but is largely famous for just a handfull of plant species of which perhaps two of the most important are Magnolia pallescens (Ebano Verde or Green Ebony) and Didymopanax tremulus (Palo de Viento or the Wind Tree). Though both are beautiful trees, the latter is especially attractive as its leaves never cease to shake, as if it were something out of a fairy tale!
We entered the access road at about 10 a.m. Although the road was unaffected, the surrounding countryside was mostly shrouded in thick cloud, bathing the environment in 100% humidity. Cloud cover is normal here, with clouds regularly entering in the mid-afternoon and evaporating as the sun rises (between 6.00 and 7.00 a.m.). Occasionally there are clear nights and, just as occasionally, there are days when clouds can last 24 hours or more.
Maintaining a National Park, especially one in a cloud forest, is not an easy task. First there is the problem of what to maintain. Should one leave plants to live and die naturally or should rare plants be protected from others that might displace them? Similarly, where should paths be cut? Then there are forest fires to prevent, the primary (historical) cause being illegal land clearance by locals wanting to engage in short-term (cut, burn, grow, abandon!) subsistence farming. Also on a large list of items to consider are invasive plants that constantly threaten to overwhelm the area. These and more require sensitive thought and intelligent actions, though all decisions are always open to potential criticism. In my opinion, Medio Ambiente (The Department of the Environment) do a good job and attempt to give minimal and controlled access (always a risk) to an area that remains largely pristine, in its natural state. However, as I will describe later, this has its risks!
So, having entered, up we went to the peak. Normally it's a 1 hour steep uphill walk in hot humid air but this time - I drove! At the peak, we entered the path down. The entry path is misleading as it starts in an unnatural environment (a mountain peak with building, viewing platform and lots of cement!). But a few steps beyond and the world changes! There one enters a forest dripping with humidity. The trees are festooned with mosses. There are epiphytic bromeliads and orchids (including tiny Pleurothallids) as well as filmy ferns (that have leaves that may be just one cell thick) and what my accompanying botanical colleagues identified as algae (but I think they are slime moulds).
Based on earlier walks here, I know that the path divides and that what was the primary site for Pinguicula casabitoana lies to the right. I've been there repeatedly, my last visit being in 1999, one year after Hurricane George. At that time, the primary habitat of P. casabitoana, a single tree, had been felled by the hurricane leaving me in some doubt as to the future of P. casabitoana at that site. A second site, again comprising a single tree, lies just a few minutes away from the first site but, again, I haven't visited there since 1999.
At one point, we passed an old wooden sign that read "Pinguicula casabitoana". I'd seen this sign once before (it was the furthest down this path that I'd ever traveled). As I had done before, we searched but in vain. Our guide insisted that this was where we could find P. casabitoana but all he pointed to were small immature bromeliads (our guide was not a botanist!). At several more points, the guide hopefully pointed to yet more immature bromeliads.
This time my aim was to visit the third and last site of P. casabitoana on Mount Casabito. So we stayed on the left-hand path. I despaired of finding plants as every tree was completely covered with moss, quite unlike my experience on all my previous adventures here. I was trailing behind with a group of three botanists. Ahead of me were three friends and my non-botanical girlfriend, Alex. Suddenly Alex called out. I'd trained her well. From my library of CP books she had learned to recognise Pinguicula and, sure enough she had indeed located P. casabitoana! But oh what a disappointment (albeit mixed with excitement). Here was yet another lone tree hosting not more than a handful of Pinguicula with no doubt some more higher up where we could not see them. Worse still and the main reason for my disappointment, the moss!!! Remembering back to site #1, I recall that the plants always grew on bare wood and that the wood was relatively smooth. I've seen P. lignicola in situ too, in Cuba. It's almost identical to P. casabitoana and it too grows on trees where there is no moss. Again from memory, P. lignicola also grows on smooth wood. So, in my opinion, this moss did not bode well for the future of P. casabitoana.
Leaving aside the expedition, let me just chat about experience. I have indeed seen P. casabitoana growing on moss, though this admission is less contradictory that in it might at first appear! The guilty plant sat dead center of a single mound of moss that itself sat and covered the stump of a dead and rotting tree. The plant appeared healthy and was even flowering. Flowers are deceptive and can be a sign of a plant suffering stress (the flowers are a last effort at survival via seed!). However, I doubt this was a deception, the plant was happy. So why do I say plants do not grow on moss? Because of the roots. The roots of P. casabitoana (and the almost identical P. lignicola) are very specialised and have developed to be highly adapted to holding on to trees (that is, wood). The roots initially grow out from the plants normally. However, they soon wither and dry up to remain on the plants as tough, wire-like structures, as thin as hair and bearing specialised circular features that stick or hold onto the wood. These are by no means designed to burrow into earth or grab hold of moss. So, returning to the odd plant on top of the moss, what exactly was it doing? This was serendipity (meaning that the plant experienced "a lucky accident" or "found something that was unexpected"). All that had happened was that a plant had fallen off the host tree and, by sheer luck (serendipity) it had landed, below, on top of a clump of moss rather than on the completely inhospitable forest floor. As this moss was relatively low in the forest, the surrounding woodland, undergrowth and terrain prevented the wind from dislodging the Pinguicula which therefore continued to live and grow where it fell. The plant could live (temporarily) because it was on top of the moss and not buried in it. Time no doubt soon changed that!
There are other examples of P. casabitoana growing in moss. Look at the photos. The most recent photo shows one plant, on a branch, with moss all around it. What's happening here? The moss is encroaching. What was bare wood hosting Pinguicula is now being taken over by the moss. I predict that in a few ears, maybe even within 1 year, the moss will cover the branch and successfully kill off the Pinguicula.
Still from experience, there is another aspect worth mentioning. It is my belief that P. casabitoana does not like liquid water. Obviously it needs water and it gets plenty of that, in vapour form, from the humid atmosphere – the peak (and entire Eastern aspect) of Casabito is never dry! I think that the smooth wood on which P. casabitoana grows is an important feature in understanding the plant's needs and dislikes. Logically, at first thought it makes little sense to be an epiphyte that wants to grow on smooth wood as getting a foothold might prove a distinct challenge. However, remember those discs on the roots. They are shaped like suckers. They obviously do allow the plant to stick to smooth wood. At the same time, other plants are challenged to attach themselves. So P. casabitoana is a pioneer species that can colonise a difficult habitat while other plants will take much longer to gain a foothold. However, another aspect of smooth wood is that it does not remain wet. So even after lots of rain, the water rapidly runs off of the wood and any remaining water is quickly dried by the heat of the day or the wind. So P. casabitoana actually lives on a substrate thatis about as dry as any substrate ever gets. The roots are so adapted to an attachment function that they play no part in water absorption. I surmise that Pinguicula has become sensitive to water such that it suffers if wet for too long. This is not too surprising. Most Pinguicula (for example, many from Mexico) are not happy if kept permanently wet (in which case they often fail to flower and are slow to propagate naturally by division). Also, Pinguicula have been likened to succulents and certainly many succulents dislike to be wet for long periods. Thinking more about mosses, these probably present Pinguicula with two problems. First, as appears obvious, moss will eventually displace the Pinguicula as, once colonised, moss will easily outpace the reproductive capabilities of P. casabitoana. Second, many mosses will remain wet after being drenched by rain. This water is (I believe) anathema to P. casabitoana and so will weaken or kill the plants.
Take one more look at the photos. Check out the Pinguicula that are on the tree's trunk (it was much higher up so more difficult to photograph). Even with the poor quality of the photo, it is clear to see that most of the Pinguicula are growing on bare wood and only one plant is growing beside a clump of moss, the moss is encroaching on the Pinguicula which would not otherwise choose to be close to moss and will not withstand the onslaught!
In the fourth paragraph (above), I mentioned that Medio ambiente "maintain" the National Park in its natural state but that, as well as being logically correct and commendable, this has risks. I said I would return to this subject. One such risk is to P. casabitoana. To my mind, there is no valid argument to dissuade me from the belief that this species is under threat from encroaching moss. I have not mentioned previously that P. casabitoana is slow to propagate. This species produces very few seeds and the mother plant divides only slowly. Of those seeds that are produced, many must tumble to the forest floor where they will quickly die or be eaten. So here we have a species that is under threat from a natural competitor for its habitat. What most surprised me is that I could find almost no other similar trees (same species as the host) that P. casabitoana could colonise. This means that similar trees are, at best, distant and that in turn means that a dispersal mechanism is needed to move seeds from the parent to a new yet distant tree! There is no evidence to support any specific dispersal mechanism but the most obvious is wind; relatively large and heavy seeds (compared to other Pinguicula species) could easily be moved by the winds associated with tropical depressions or hurricanes. Yet overall, this means that reproduction is at risk of being outpaced by moss, putting the species in peril. So an important question is, should mankind intervene? In a National Park where the aim is to conserve what is natural, should we make an exception and remove encroaching moss from some trees so as to safeguard the continued existence of a rare species that is under threat? Should we also plant a few new trees so as to provide a future moss-free and smoothe-barked environment for P. casabitoana? I doubt there is a good answer that everyone would agree with but perhaps there is a least worst solution?
Returning to the expedition, we found no more traces of Pinguicula. Indeed, this 3rd site is probably at the lower limit of acceptable habitats for P. casabitoana as the terrain rapidly changed and it was obvious that we soon left the dripping cloud forest for a drier environment, unsuited to P. casabitoana and many other cloud forest epiphytes.
I will return to Casabito (now that I live in the Dominican Republic, Casabito is only 40 minutes away) and I hope it will be in significantly less time than the 12 years that passed since my last visit! P. casabitoana is not explicitly a protected species but all the habitats where I know it to grow (where I have seen it) are protected! So obtaining a specimen to experiment with is a challenge, to say the least. Please note that I do not own any specimens (living or dead), not even seeds.
Because I know it will cross the minds of some, I can confirm that visits to see P. casabitoana are possible. All such visits will be accompanied by employees of Medio Ambiente who will stick-like-glue to the visitors to prevent plant theft, especially of P. casabitoana. The mountain road across Casabito has very recently (2010) been upgraded to a very high standard. This means that it is possible to leave Santo Domingo (the Capital) very early in the morning (5.30 a.m.) and have time for breakfast and to see the plants as well as still having time to return to Santo Domingo the same day. (I do not recommend afternoon visits – very heavy rain is more likely in the afternoon.) A full walk starting and finishing at the same place will take most of a day. Trips to just P. casabitoana (starting from Casabito) can take about 2 hours. If anyone has an opportunity to do this and wants my help, I need a few days notice to get the necessary permission, less if all you want is advice.
Finally, I would like to express my thanks to Ramon Emilio, of Medio Ambiente, for his help and permission, which enabled the visit to see P. casabitoana to be possible. My thanks are also due to Isao-san (Isao Takai, who many will know through his association with various carnivorous plant societies, journals and web or internet services), who is a long time friend and who helped publish this article.
04 July 2011