Excerpts from Jim Conrad's
from the June 26, 2011 Newsletter issued from Mayan Beach Garden Inn 20 kms north of Mahahual, Quintana Roo, México
COASTAL STRAND VEGETATION
The long, narrow sand ridge I'm living on now, wedged between the Caribbean on the east and a big mangrove swamp to the west, is cloaked with a fragile and unique plant community known as coastal strand vegetation. You can see an example I visit daily above.
Coastal strand vegetation forms along shores in loose sand just above the high tide mark. Many plant species in this special kind of environment are endemic -- in the whole world occurring naturally only in this small region. Species diversity in coastal strand vegetation is low because few plant species can tolerate the zone's harsh conditions, which include high wind, salt spray in the air and high salt concentrations in the sandy soil, and that sandy soil itself -- basically plain sand -- has a very low holding capacity for both nutrients and water. Many plants in such zones are succulent.
An interesting feature of coastal strand vegetation is that very often its structure and general appearance is very similar to coastal strand vegetation in other parts of the world, even though the species in the two communities may be completely different. Most coastal strand environments are windblown and salty, so plants growing there, no matter what their kinship is, will be highly adapted to wind and high levels of salt. Salt-tolerant plants are often succulent because succulent stems and leaves retain more water than non- succulent ones.
In the above picture of our local coastal strand vegetation, the shrub with large, round leaves up close is Seagrape. The low, scrambling, mat-forming plant behind it is Sea Purslane. The dense, grayish shrub at the right is Sea-Lavender. The orange-green shrub behind and to the right of the Sea-lavender is Gullfeed. These coastal strand plants and others of this area can be reviewed on our "Notes on Flowering Plants & Ferns of Beaches & Saltwater Lagoons" page at http://www.backyardnature.net/yucatan/seashore.htm.
You might enjoy Googling the keywords "coastal strand vegetation ######" with ###### replaced by the name of another part of the world, such as California or Australia. On resulting pages you can see what plants in those places have evolved to occupy the coastal strand environment. You've seen that Beach Gentian is one of our coastal strand wildflowers. I see Beach Gentian missing on a list of California's coastal strand vegetation, but they have Bush Lupines, which must be nice, too.
Of course a prime danger to the coastal strand is human beings building on the beach. Often large parts of the beach are scalped so that prospective land buyers can more easily see the land.