How Sex, Politics, Money and Religion are Killing Planet Earth

Wednesday, September 14, 2011

Poisonwood and Other Guardians of the Woods

I am in transit from Grand Bahama Island on my way back to Turks and Caicos, sitting in the Miami Airport, scratching welts on my arms and legs.

While in the Bahamas, I was surveying the terrestrial ecology of an area of Pinus caribaea var. bahamensis woodland. The area is slated for land clearance, and I was hired, as I often am, to catalogue the ecology of a place prior to its destruction. The work is sometimes frustrating.
Grand Bahama is spoiled in terms of pine woodland areas. Almost the entire island is covered with them, with a few other areas of wetlands, coastal habitats, intermittent sandy dunes and tidal mangrove estuaries. The human population is primarily centralized on the western end of the island, leaving much of the remaining areas wild.

Given the predominance of pines, and the fact that they have a nasty habit of catching fire and threatening nearby structures, prescribing conservation of these habitats is a hard sell. But with a little luck and persuasion, the generally conscientious Bahamians are happy to discuss mitigation and relocation of threatened and endangered species, when possible. Life as an environmental scientist is all about the little victories.

As a frequent resident of temperate mountain forests, I have forged a hate-hate relationship with poison ivy (Rhus spp). The Cherokee in my area have a different perspective. They say that poison ivy is the guardian of the forest. It usually grows at the edges of the forest or in areas that have been cleared. Its purpose is to keep out those who would do harm (or not), so they say.  

The Bahamian pine woodlands also have a guardian, Metopium toxiferum or “poisonwood.” While poisonwood is a tree or shrub, not a vine, poisonwood and poison ivy are close cousins, both hailing from the Anacardiaceae family, and they share a similar irritating, oily defense mechanism. Thus my system, made ready from years of exposure to poison ivy, readily welts in the presence of her tropical cousin.
The thing about poisonwood in the Bahamas is that it is the dominant understory species in the pine woodlands. Every square meter sample of every transect counts at least one individual. Apparently, the pine woodlands are in extreme need of protection. Nature clearly wants to keep naked-skinned mammals out of her woodlands.
A pine woodland on Grand Bahama impacted by Hurricane Wilma. Only a few years later, new life emerges.

In the past centuries, the Bahamian pines were cleared relentlessly for lumber, yet they have managed to recover. I wonder if the contemporary pine/poisonwood association resulted from these previous assaults. No quantitative records exist to confirm this hypothesis. Just as animals exposed to hunting become weary of humans, I imagine the pine woodlands are also now wise to the world and are protecting themselves against a hostile new reality. As I scratch and scratch and praise the gods of Claritin and Benadryl, I find solace in these thoughts. 

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