Study on the effects of Hurricane Wilma on Epiphytes (Orchids and more)

[Tindomul]

Laurel K. Goode and Michael F. Allen from the Center for Conservation Biology at U. of California; Riverside, have published a paper "The impacts of Hurricane Wilma on the epiphytes of El Edén Ecological Reserve, Quintana Roo, Mexico".
They compare the abundance of epiphytes before and after the passing of Hurricane Wilma (October 2005, Category V) in Quintana Roo which is located 30 Km northwest of Cancun and is an example of a seasonally dry forest (meaning its a rain forest for part of the year).
Hurricane Wilma passed directly over this reserve with sustained winds of 161 km/hr and gusts of 209 km/hr and the eye of the storm held directly over the reserve for two days before heading for Florida. It left 1.5 m of rain. The more mature forests were expected to sustain more damage because the taller trees here would be more vulnerable to wind damage. Most trees lost their leaves exposing surviving epiphytes to the environment.
Before the Hurricane they surveyed 3191 individual epiphytic plants, of which 2254 were in the tintal wetlands (seasonally flooded). The wetland had 2 Orchidaceae species along with 5 Bromiliaceae, which together accounted for 93.4% of the epiphytes there. Rhyncholaelia digbyana (10.9%), Myrmecophylla tibicinus (8.0%).
The mature forest of El Edén was the most species rich. Tillandsia brachycaulos was the dominant epiphyte (67.9%), along with Syngonium podophyllum (7.5%) and Philodendron hederaceum (7.7%).
The younger forests (young due to recent man made fires) had Tillandsia as the majority along with Selencereus donkelaari (Cactaceae) and Catasetum integerrimum. Only one of the three secondary forests (young forests) had no epiphytes before the hurricane, and this one found 1 afterwards, C. intergerrimum.
More than 3000 living individuals were observed before the hurricane and only 1454 living individuals were counted afterwards. More than 50% of all epiphytes were lost, but over all the species composition (number of each species compared/relative to the others) was similar in the older forest and one of the younger forests.
In one of the younger forests, two Tillandsia sp. were recorded, but after Wilma, two different Tillandsia were found and one Oncidium ascendens were observed. In the wetlands, Brassavola nodosa and Encyclia alata along with Tillandsia dasylirifolia experienced losses that exceeded 80%!
The density of epipytes still on standing trees was reduced by 27.6% in the mature forests. The younger forests lost 71% of epiphytes.
Hurricane Wilma dropped 1.5 m of rain (thats around 5 feet!) and because of this many of the wetland epiphytes were submerged while still attached to standing vegetation (most epiphytes observed were found under the canopy). This accounted for most of the losses. This finding is opposite to expectations that mature forests would suffer the most.
It has been hypothesized that the timing of capsule (orchid seed pod) opening may be related to the occurence of tropical storms, because the seeds are so tiny and capable of traveling long distances. This may give the possibility that recovery of the epiphytes may be quick. However it is feared that if the current trend of increasing frequency and intensity of tropical storms (due to climate change), that in the future there will be little or no time given to ecosystems to restore themselves or epiphytes to pre-storm levels.
To read this article, please go to Journal of the Torrey Botanical Society Volume 135, Number 3 July-September 2008.
Comments and questions appreciated.

Table included shows the effects of Wilma on the epiphytes. SF1, SF2, and SF3 are three distinct secondary forests (young forests). The first numbers represent the number of individuals observed before Wilma and the second represents the number of individuals observed after the passing of Wilma.

[Tindomul]

Updated

[isurus79]

Very interesting article Tindo. Im surprised that more people have not checked this article out. It also kind of surprising that the taller trees were able to better withstand 160+ MPH winds better than their younger counterparts. I would imagine, however, that the older trees probably have much thicker, stronger bases for support. I wonder if the authors will do a follow up report?

[Tindomul]

Well the article doesn't cover the damage to the trees themselves. What the surprising outcome was that there were more losses in the wetlands habitat than in the mature forests habitat, precisely because of the placement of most of the epiphytes (low enough to get drowned by the flood).

[dgenovese1]

Tindomul,

Intersting article. I've wondered how the storms affect the orchids in the swamps around where I live, like Corkscrew, the Fakahatchee and the Everglades. This has given me some insight.

Thanks!

[Sun rm.N.E.]

Tindomul

Thank you for posting this article. It will be interesting to see how well the orchids and the Tillandsias recover. If you have time please keep us informed.