It was as if the class had just stepped out onto the moon the way the limestone craters pockmarked the area's surface. It looked most uninhabitable indeed! Yet, here and there tufts of sawgrass had naturally reseeded and sprung up to reclaim the land. Like the American flag hoisted in place by Neil Armstrong on the moon, the tufts of sawgrass seemed to be saying, "One small step for sawgrass, one giant leap for the Everglades ecosystem!" Indeed, to witness the success of the Hole-in-the-Donut Restoration Project is like being the captain of a boat lost at sea catching a break in the fog long enough to glimpse a beacon's light before it becomes shrouded again in the mist of politics, economics and bureaucracy. Yet, that brief glimpse of light is enough to encourage even me, an increasingly cynical and apathetic environmentalist, to trudge on.
Before this seemingly barren lunar landscape emerged, the first invasive exotic species to colonize what would later be called the Hole-in-the-Donut area were a group of Homosapiens sapiens subsp. agricultis, otherwise known as farmers. After the last of the farmers left in the early 1970s, they left behind a rock-plowed, slightly elevated patch of land pregnant with nutrients otherwise not known in the mesic prairie wetlands that originally occupied this space. Thus, the scene was set for one of the most destructive vegetative invasions seen in the Everglades ecosystem thus far. The army came from Brazil and was crafty enough to get its enemy to use its own resources to advance its invasion. Its weapon: clusters of bright red berries that enticed the likes of Florida's state bird the mockingbird, cedar waxwings, and especially migrating robins (1) to come in for a meal and then disperse its seeds into uncolonized territories possibly miles away from the parent plant. This plant, a common roadside attraction now in south Florida, is called Brazilian pepper.
Also known by the misleading name Florida holly, since in the past its winter fruiting habit allowed its branches to be used to make holiday decorations, botanists refer to Brazilian pepper by its scientific name, Schinus terebinthifolius Raddi. Properly pronounced "sky-nus" the generic name comes from the Greek word for the mastic tree while the species epithet is derived from the Latin word for turpentine (terebinth) plus leaf (folium) (2). Aptly named (if you're in doubt, just crunch up a few leaves to see what I mean), Schinus belongs to the same resin-bearing plant family that brings us cashews, pistachios, mangoes, lacquers, and poison ivy. And, indeed, not only has this plant proven detrimental to native plant populations, it has also been known to cause skin irritations and rashes upon handling as well as respiratory complaints and hayfever symptoms while blooming.
According to Julia Morton, seeds of Brazilian pepper first arrived in Washington, DC in 1899 with the seeds or seedlings grown from them sent to the Plant Introduction Station in Miami where some plants were distributed locally (3). But according to Richard W. Workman, Administrative Director of the Sanibel-Captiva Conservation Foundation, Brazilian pepper was first introduced in Florida in 1891 by Reasoner's Tropical Nursery in Bradenton (4). Regardless of the exact dates, both writers probably would agree that Brazilian pepper got its foot in the door in Florida when a doctor named Dr. George Stone living in Punta Gorda grew seedlings from seeds he had acquired from somewhere in Brazil. In Volume I of the 1944 edition of My Garden In Florida written by Dr. Henry Nehrling, Dr. Stone is reported to have "distributed these seedlings freely among his friends, and plant lovers, and many were planted out along the city streets." (5). Nehrling goes on to comment on his admiration for "the unique beauty of a fine specimen in full fruit," suggesting that "It ought to be in every garden in Florida." (6).
Little could Nehrling foresee, though, that by the early 1970's most natural area land managers would become all too familiar with the destructive growing behaviors of his uniquely beautiful plant and had initiated efforts to control its spread (7). Such aggressiveness in growth even led University of Florida botanist Jack Ewel in 1978 to question whether or not Brazilian pepper was not the perfect weed:
Schinus terebinthifolius has many characteristics possessed by other weedy pioneer species: it grows rapidly; it is a prolific seed producer; its foliage flushes nearly continuously; it coppices vigorously, and it tolerates a wide range of site conditions. As a weed tree, however, it is nearly unique in terms of the broad spectrum of characteristics which it also possesses which are more typical of mature ecosystem species: it produces relatively large, animal-dispersed seeds; it has relatively large cotyledons which aid in seedling survival; it is dioecious; it is insect pollinated; its seedlings are remarkably capable of survival in shade conditions, and its reproductive activity is remarkably synchronous and compressed into a very short period (8).
In this same paper, Ewel, whose valuable research on the ecology of Brazilian pepper at that time was being conducted in the Hole-in-the-Donut, goes on to propose possible control strategies. Interestingly enough he proposes:
One possibility is to completely devastate the Schinus-dominated stands (by bulldozing and burning, perhaps) and encourage recolonization by desirable species. Such scorched-earth approaches to ecosystem management are, however, not in keeping with the philosophies of most natural reserves, parks and wildlife units. Furthermore, drastic site disturbance creates the near-perfect habitat for Schinus reinvasion: a rabbit-in-the-briar-patch situation (9)!
Yet, in 1989 a pilot project conducted on 24 hectares in the Hole-in-the-Donut showed that the only way to completely get rid of the established Brazilian pepper forests and return them to their original mesic prairie wetlands status was to bulldoze the above ground parts and remove the entire growing substrate down to bare limestone rock. Otherwise, the study showed that if any soil was left behind recolonization of Brazilian pepper was inevitable. Basically, this strategy works by returning the land to its normal elevation and nutrient levels which in turn has an effect on the area's hydroperiod allowing it to remain underwater for longer periods of time during the wet season. Under these nutrient deficient, wet conditions it appears that Brazilian pepper seedlings are unable to grow.
The results from this pilot study finally had latched upon an eradication strategy that worked and in 1993 this strategy was embodied in the Hole-in-the-Donut Restoration Project and commenced. The restoration project basically involves, as our class witnessed, bulldozing large areas of Brazilian pepper trees down, mulching and then piling them up at specific sites, and lastly scraping the substrate down to bare rock creating the lunar-looking surface described in the beginning of this paper. After observing the whole scheme in action, the first thing I can think of to say is that it is truly amazing and almost unfathomable to think that one species of plant could require so such heavy equipment to eliminate! It also poignantly illustrates just how serious the problem of invasive exotic plant species really can get.
Currently, all one needs to do is drive along any of the many canals that traverse the southern half of Florida to see just how prolific Brazilian pepper can be. And, perhaps, on one of these drives, one might ponder what strategy needs to be employed to eradicate these trees? This is a good question indeed, for unlike Everglades National Park, there is no intention of restoring the many canal-lined housing subdivisions back to their original status, and it is obvious that bulldozing, mulching, and scraping is not a viable option! One could even question why it would be necessary to remove these plants at all seeing that most vegetation used in landscaping these new topographic additions is non-native as well. And again, the answer brings us full circle around to the role the Everglades ecosystem plays as a life support system to the citizens of south Florida and the health of which allows us to keep enjoying the quality of life we currently are experiencing. But, unfortunately, like breathing, this all too often seems only to be taken for granted.
1) Morton, JF. 1978. Brazilian pepper, its impact on people, animals, and the environment. Econ. Bot. 32: p. 354.
2) Workman, R, ed. 1978. Schinus: Technical proceedings of techniques for control of Schinus in south Florida: A workshop for natural area managers. Tech. report. Sanibel (FL): The Sanibel-Captiva Conservation Foundation, Inc. pg. 5.
3) Morton, JF. 1978. Brazilian pepper, its impact on people, animals, and the environment. Econ. Bot. 32: p. 354.
4) Workman, R, ed. 1978. Schinus: Technical proceedings of techniques for control of Schinus in south Florida: A workshop for natural area managers. Tech. report. Sanibel FL): The Sanibel-Captiva Conservation Foundation, Inc. pg. 5.
5) Morton, JF. 1978. Brazilian pepper, its impact on people, animals, and the environment. Econ. Bot. 32: p. 354.
6) Morton, JF. 1978. Brazilian pepper, its impact on people, animals, and the environment. Econ. Bot. 32: p. 354.
7) Workman, R, ed. 1978. Schinus: Technical proceedings of techniques for control of Schinus in south Florida: A workshop for natural area managers. Tech. report. Sanibel (FL): The Sanibel-Captiva Conservation Foundation, Inc. pg. 1.
8) Workman, R, ed. 1978. Schinus: Technical proceedings of techniques for control of Schinus in south Florida: A workshop for natural area managers. Tech. report. Sanibel (FL): The Sanibel-Captiva Conservation Foundation, Inc. pg. 19.
9) Workman, R, ed. 1978. Schinus: Technical proceedings of techniques for control of Schinus in south Florida: A workshop for natural area managers. Tech. report. Sanibel (FL): The Sanibel-Captiva Conservation Foundation, Inc. pg. 19.