The Lesser Antilles: a Lesson in Conservingnatural Resources
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The Lesser Antilles: A Lesson in ConservingNatural Resources Raymond W. Doyscher, Jr. is the name given to an arc- THE LESSERANTILLES TABLE1. Summaryof Krakatoa'sHistory of Re-biogenation* shaped chain of numerous small islands in the Carib- Downloaded from http://online.ucpress.edu/abt/article-pdf/41/2/86/36865/4446484.pdf by guest on 26 September 2021 from Puerto Rico southward to the bean, stretching Year Biotic CommunityObserved northern coast of South America. Geological records indicate that the oldest islands in the chain began to 1881 Volcano-no recordedlife form exist. emerge from oceanic volcanoes 30 millionyears ago. 1884 1 spider. No other life forms recorded. Martinique, Dominica, and Guadeloupe were com- floweringplants. pletelyformed 25 millionyears ago, St. Vincentabout 10 1886 11 ferns, 15 millionyears ago. 1897 Much green covering. Coconut trees on the island the edge common. Sugar cane common. 4 orchid Latercoral reefs made theirway to ocean surface species. on the easternedge of this islandchain. They evolvedas 1907 263 animalspecies-including insects, birds,reptiles, a result of the incessant and tenacious activityof tiny and land-snails. marine animals working on the volcanicallyelevated 1930 Dense forest coveringthe whole island. Muchgrass- ocean floor. From this coral emerged EasternGuade- land with wildflowers.Almost 50 species of verte- loupe, Anguilla,Barbuda, and Antigua.None of these brates. Two mammals-bats and rats. 1,200animal islandshas ever been a part of a continentalland mass. species observed. They offer biologists a unique opportunityto observe and identifyprinciples of ecology and conservationthat exist nowhere else on earth. *Basedon informationfrom Moore 1964. Island The Physical Conditionsof the Physical differences occur in the topographical fea- The islandsare tropical.the hot equatorialsun domi- tures. These features directly affect the soil condition nates the climateof thisarea, and little seasonal variation and the quality of rainfall that, in turn, affect the biotic occurs. The directionand velocity of the wind and the community. Rainfall can, in fact, vary greatly from one tropicaltemperatures are, for the most part, shared by part of an island to another. Three hundred inches may all these Lesser Antillesislands. fall annually on Mt. Diablotin on the isle of Dominica, but the sea-level area may receive only 50 inches. Likewise, RaymondW. Doyscher, Jr., has been teachinga on St. Lucia, rainfallis over 150 inches in the mountains varietyof science courses for the past ten yearsat but less than 60 inches on the beach. In the more level, East Detroit High School, East Detroit,Michigan nonvolcanic island, Barbados, the island center gets 80 48021.He receivedhis B.S. degree in biologyfrom EasternMichigan University in 1965;his M.A.de- inches as compared to 50 inches on the shore. gree in educationalpsychology from Wayne State Universityin 1968;and his M.S. degree in biology The Originof the IslandBiology from the Universityof Montanain 1971.At East A Detroit High School, the courses Doyscher has 11, For insight into the biotic origins of these islands, I con- taught included biology, chemistry, physiology,conservation, and physicalanthropology, a course he designedhimself. Many of his les- sulted three sources: (1) the biogenesis advocates of long sons are basedon colorslides taken on his travelsthroughout the Uni- ago; (2) the information supplied by the lava-covered Isle ted States andabroad. This article is basedon slidestaken during a visit of Krakatoa; and (3) some experiments conducted by to the Lesser Antilleswhere he investigatedthe physicalorigin of the islands,their biological development, and the effectof humanoccupa- Charles Darwin. tion on the naturalhabitat of the islands.Doyscher's sources of infor- Redi in the 17th century, Spallanzani in the 18th cen- mation included island guides, natives, and experienced fellow tury, and Pasteur in the 19th century have virtuallyelimi- travelers,all of whom were eager to share their knowledgeof the Antilleswith him. Doyscheris an activemember of NABT,and he has nated any possibility that these islands were populated publishedpreviously in Science Review. by spontaneous generation. They successfully con- 86 THE AMERICAN BIOLOGY TEACHER, VOLUME 41, NO. 2, FEBRUARY 1979 * ... a T~3o 28OURHA PAS + ATLNTI rs~~~~~~~~~~~~~~~~~ /\c OCEAN~C/ X I r4 Downloaded from http://online.ucpress.edu/abt/article-pdf/41/2/86/36865/4446484.pdf by guest on 26 September 2021 JAJI1l PiJEgro J~~~~~~~~~~~~~cos Ar ?R DOMRINICA $EA G00A PR84 l ~~~~~ANTILLESeO VIA/ET C ACv T5 R0Rr.40 FIGURE1. Geographicallocation of the Lesser Antilles. vinced the scientificworld that life can come only from America, Central America, and the older Greater pre-existinglife (Asimov 1964). AntillesIslands. The second source of informationexamined in the Scientists know that once an islandemerges from the data collectedon the repopulationof an islandin the East depths of the oceans, the floraand faunasoon reappear Indies, which was wiped clean by a volcanic eruption. in both abundanceand variety.It is also accepted that The island, Krakatoa, was rendered a lifeless, lava- the bioticoccupation had to have livingancestry on the covered rock afteran eruptionin 1883.With a greatdeal mainland.Yet an importantquestion remains. How did of intrigue,biologists reported how the islandrecovered lifeget fromthe mainlandto the islands?Charles Darwin, its floraand fauna.Table 1 traces Krakatoa'sattempt to the third source, offers some insights on the originof repopulate. islandlife. Naturally,Krakatoa's biology is still changingand will In his book,The Originof Species (1960),Darwin de- continue to change. Even in an ecologicallyclimaxed scribedhow he investigatedthe "meansof dispesal,"the area, a disease or the introductionof new competition way an organismgets from one area to another. His can quicklyand dramaticallyalter the course of a seem- experimentsand observationsmay be summarizedas inglystable and quiet ecosystem. FromKrakatoa's story, follows: we can gain insightinto the privitivebiotic development Darwinclaimed he germinatedseeds thathad been left of each of the CaribbeanIslands. The originalimmigrant in salt water for as long as four and one-halfmonths. species would have come from South America,North Branches carryingseed-containing fruit were observed LESSERANTILLES 87 to float for three months. Soil trapped behind a rock sur- rounded by a tree root sometimes contains viable seeds; Darwin dislodged three seeds from a 50-year-oldoak tree and found that they still had the potential for germinating. Darwin had very little difficultygerminating seeds from excrement and from pellets disgorged by birds. He force- fed seeds to a seed-eating fish, and then fed the fish to birds. After the contents passed through the digestive track of these fish-eating predators, the seeds were separated from the excrement. They, too, germinated. From the leg of a dead partridge, a six-ounce "ball of earth" yielded enough seeds to grow 82 plants. In another separately cited incident, Darwin told how a "lit- tle cake of dried earth" yielded a seed of a Juncus bufonius, which germinated and then flowered. Darwin also reported sighting a swarm of wind-blown FIGURE 2. Marigot Bay in St. Lucia-a large mountainous rain forest Downloaded from http://online.ucpress.edu/abt/article-pdf/41/2/86/36865/4446484.pdf by guest on 26 September 2021 island. locusts flying 370 miles off an African shore. The implication and revelance of these experiments are obvious. Nature is not without methods of populating Kitts, St. Lucia, St. Vincent, Tobago, and Trinidad are isolated islands. The islands' ancestral life would the oldest and largest of the island chains. Because of originate from four sources, including: their exaggerated mountain peaks resulting from vol- 1. Flying animals. Birds, insects, and bats would come canic activity, these islands receive copious amounts of lost in storms or would arrive while following migrational precipitation. Moisture-carrying clouds forced to rise as patterns. With unoccupied ecological niches existing, they pass the high peaks cool rapidly, and the resulting the invitation to remain would be too good to decline. condensation is the source of the rain forest's moisture 2. Floating debris. Branches with fruit, old roots, or supply. Some representative figures of annual rainfallin fruits alone, are able to transport an endless variety of the island's rain forests are: Dominica, 250 inches, St. embryonic forms, including seeds, insect eggs, and prob- Lucia, 150 inches; Grenada, 140 inches; and St. Vincent, ably reptile eggs. Logs dislodged from shores in which 100 inches (Macmillan 1974). live snakes are housed could also serve as carriers. In addition, the volcanic soils are rich in minerals. With 3. Seeds from gullets, feet, and plumage of birds. Most plentiful water, fertile ground, and an equatorial sun, the seeds are small and protected by a hard coat making flora and fauna would have existed in almost an endless them resistant to desiccation and digestion. Seeds de- variety. We can verify this through the present existence posited from a bird's alimentary canal even have the of virgin tropical rain forests in South America. Further- advantage of an immediately fertile environment. more visitors to the islands can still observe a secondary 4. Air drifts. Fern, algae, and fungal spores have a reforestation of what was once undisturbed wilderness. weight and density equivalent