|This is an article about restoring wild palms in their wild places. As a
horticulturist, I delight in the cultivation of palms from around the world. As an
ecologist, I live with a profound sense of loss, knowing that some palm species may exist
only in gardens, their natural habitats destroyed.
As former Curator of Endangered
Species at Fairchild Tropical Garden, I know that botanic gardens are more than just
pretty places. Palm collections such as Fairchild's provide a tantalizing example of the
diversity of palms that have evolved in dynamic natural systems. Yet palms grown in the
controlled simplicity of a garden are at an evolutionary dead-end. Therefore, the
collections and scientific resources of botanic gardens should be used to re-establish
rare palms in appropriate natural habitats, where species can continue to evolve with a
myriad of mingling plants and animals. Reintroduction of plants into conservation areas is
becoming a more common practice in efforts to prevent extinction of endangered species
(Falk and Olweu 1992).
Transplanting of an endangered species might take place if a site is being cleared and
the plants would otherwise be destroyed, or for restoration of a wild population that has
dwindled due to human activities. While championing endangered species reintroductions, I
do not advocate jaunts into the woods to add to the flora to an area or to spread around
species which one personally thinks should be more abundant. The motive for reintroduction
should be more than an impulsive urge to right a wrong. Reintroduction should be a
carefully planned and documented experiment in restoring a lost or abused member species
in a native plant community. Scientific staff of The Nature Conservancy, an
international conservation organization that manages numerous nature preserves, recently
developed an elegantly simple dichotomous key to help in deciding when species
reintroductions are appropriate (Gordon 1994). First, is the species really threatened?
Are there protected populations? Is there protected habitat within the known range of the
species? Has the original cause of species decline been identified and eliminated? Are
verifiable and legal propagules available? Is site management within the requirements or
tolerance of the species?
These questions will be addressed in the following description of a relatively
straightforward reintroduction project for a threatened palm species in south Florida.
While not the perfect model, it is an example of a stepwise process that we hope will
result in a thriving and self-sustaining palm population in the wild.
A Rare Florida Native: Pseudophoenix sargentii
Pseudophoenix sargentii H. Wend. ex Sargent, the Sargent's cherry palm, was
first discovered in 1886 on Elliott Key, an island ten miles from the shores of Miami,
Florida, and was first described from specimens collected there (Sargent 1886). Soon
thereafter, Pseudophoenix sargentii was found on Sands Key, adjacent to Elliott
Key, and on Long Key, about 50 miles southwest of Elliott Key. Even upon discovery, palm
populations on these three islands were small, from a few dozen to a few hundred palms. A
thorough and disheartening chronology of the status of this palm species in the Florida
Keys, from its discovery through the late 1950's, was published in an early Principes article
(Ledin et al. 1959) (Figs. 1,2). Hundreds of these attractive palms were dug up from Long
Key to be sold as ornamentals, and a scraggly few remained. On Elliott and Sands Keys, all
but a few of the palms were cleared for island plantations and homesites.
Ten years after Ledin's surveys of Pseudophoenix sargentii, the interior of
Elliott Key was bulldozed by spiteful developers just prior to federal purchase of the
island for the formation of Biscayne National Park. By 1991, when volunteers and I had
resurveyed all of the historical locations of the Sargent's cherry palm, no palms were
found on Long or Sands Keys, and fewer than fifty palms remained on Elliott Key (for a
full account, see Lippincott 1992).
The small Sargent's cherry palm population in subtropical Florida is peripheral to the
species' wider distribution along the tropical coastlines of the Bahama Islands,
Hispaniola, Cuba, and the Yucatan Peninsula of Mexico. Throughout its range in the
northern Caribbean, Pseudophoenix sargentii is increasingly threatened by the
activities of humans. On most of the shores where it occurs, Pseudophoenix sargentii is
threatened by imminent development, as impoverished Caribbean nations lure foreign
tourists with resorts and vacation homes. Mature palms are frequently dug from natural
areas and transplanted into gardens, with few surviving the move. In areas such as Saona
Island, a U.S. Coast Guard base where the wild palms are protected from harvest, almost no
young palms are found because feral grazers such as goats feast on fruits and seedlings
(R. W. Read, personal communication). Reproduction of Sargent's cherry palm is also
compromised by excessive fruit collection for livestock feed. In summary, the survival of
wild populations of Pseudophoenix sargentii throughout the northern Caribbean is
tenuous. In Florida, the Sargent's cherry palm has been reduced in the last century from
hundreds of palms on three islands to a few dozen palms on one island. We decided that
this palm met the criteria of "threatened," and proceeded to plan for its
restoration on the three Florida islands where it once occurred more abundantly.
Although I will use the term "reintroduction" inclusively in this article,
the term is strictly defined (IUCN 1984) as the reestablishment of a species which no
longer exists at a site, as in this case, the return of Sargent's cherry palms to Long
Key, where palm harvesters had extirpated the wild population. Since palms still exist on
Elliott Key, replanting on that island is correctly termed "restocking," and is
usually done to moderate genetic risks associated with reduced population size.