Status of mangrove research in Latin America and the Caribbean

Bolm Inst. oceanogr., S Paulo, 38(1):93-97, 1990 Status of mangrove research ln Latln Amerlca and the Carlbbean(*) Yara SCHAEFFER-NOVELLI & Gilberto CINTRON1 Instituto Oceanográfico da Universidade de São Paulo (Caixa Postal 9075, 01051 São Paulo, SP) • Abstract: For those in the eastem hemisphere, the most slfiking characteristic of New World mangroves must be their low diversity. However, this apparent simplicity is deceptive, New World mangrove species are extraordinarily plastic in their adaptations to their environment. On a geographic basis mangroves attain their greatest development where rainfall and tidal subsidies are abundant. These conditions occur in the northwest part of South American continent and on the eastem seabord, south of the Gulf of Paria (Venezuela) to São Luís, in Brazil. ln the 1970's events related to the developing environmental movement in the United States led to a marked interest in these systems, their ecology and management, pointing out the ecologica1 role of mangroves as sources of organic matter to estuarine food webs.The economic recession of the SO's and its impact on funding agencies, both national and international, and changing national priorities have dramatica1y curtailed scientific research. Research in the region is now almost totally supported by local institutions.The alanning rate at which mangroves are being destroyed in the region requires that prompt action be taken to develop a regional program such as the one recommended in the UNESCO Cali 1978 meeting, capable of fostering and supporting ecosystemic research, the development and compilation of management guidelines and the training of scientific person~ resource managers, and providing for public environmental education. These guidefuies and strategies for effective management of a complex resource can only be developed through research. . • Descriptors: Mangrove swamps, Geographica1 distribution, Historica1 account, Research programmes, Latin America. . • Descritores: ManguezaÍs, Distribuição geográfica, Avaliação histórica, Programas de pe~uisa, América Latina. Introduction From earliest colonial times, mangrove forests captured the attention of New World explorers, settlers and naturalists. Coming from temperate coas tal landscapes dominated by herbaceous marshes, they were fascinated by these remarkable trees with the ability to ~row in seawater, forming impressive and often 1Dlpenetrable maus of aerial roots. They soon discovered that these plants yielded useful products like timber, (e) Paper presentcd at the "lntemational Conference on Mangrovcs", beld from Dcccmbcr 1 to 5, 1989, in Okinawa, invitcd by the Japancac Gmoemment. (1) Department of NatutafRc&ourc:cs Commonwcltb oC Puerto Rico, San Juan, P.O.Bóx 5887 - Puerto Rico. Contr. no. 719 do Inst.'oceimogr. da Usp. . firewood and bark for taoning leather. ln contrast to the indigenous populations that had lived, fished and made use of these forests for millenia without drastic alterations, New World settlers initiated dramatic changes that uJiimately have led to the depletion or degradation of the resource. ln facto as early as 1760, the cutting of mangroves for fuel wood in some provinces of colonial Brazil had reached such proportions that it had become difficuJi to obtain bark for tannins, causing its price to rise sharply. As a result, the King of Portugal, Dn. José, had to issue a proclamation ordering that only debarked trees could be used as fuelwood Violators faced rIDes and incarceration. Unfortunately, in spite of this early rudimentary attempt to manage for multiple uses, New World mangrove resources have not been historicallyregarded as valuable or important. ln fact, they have been and are unfortunately still considered obstacles to economic development or as lands suitable for reclamation. The 94 only perceived value is often their real estate value (afier filling), especially in highly prized coastal areas. ln tbis paper we will give a brief overview of some characteristics of New World mangroves and their environment, specifically those related to their management, and will review some of the efforts that have been made in Latin America to foster regional research. New World mangroves and their environment Bolm Inst. oceanogr., S Paulo, 38(1),1990 overwhelming fresh water discharge and intense tidaI and wave energies. The beIt of greatest mangrove development is roughly restricted to within 10 degrees of the equator except on the Pacific coast of South America, where the cold Humbold Current suppresses convective activity and creates extremely desertic conditions. The terminus of mangrove forests on tbis coast lies at the mouth of the Thmbes river barely 03°48' south of the equator. Isolated mangroves occur further south (to about 5°3O'S) but conditions along the remainder of this barren coast are not conductive to mangrove establishment or development. On the AtIantic sié:le, on the other hand, mangroves develop as far as 28"30'S along the Brazilian coast, where they eventua11y become limited by low temperatures and sporadic frost events. Mature red mangroves at their but latitudinal Southern limit barely reach 1 meter ~ black mangroves still reach more than 8 meters in height at Laguna (2S030'S). ln fact the landscape here is dominated by herbaceous vegetation (Spartina) with scattered and isolated white mangrove (Laguncularia )clumps. On the Latin America northern hemisphere mangroves reach 31°N near Puerto Lobos, Gulf of California. On the Gulf coast of Florida they reach 3QD24'N, whereas on the Atlantic coast theyreach 29"54'N, and on the Bermuda island they occur at 32°N. For those in the eastern hemisphere, the most striking characteristic ofNewWorld mangroves must be their low species reachness. Old Werld areas have a very large number of species (more than 40) when compared to the species poor New World mangroves (less than 10). A1though these numbers may change depending upon which species are considered "troe" mangroves or "major species", certainly this difference is of great interest because of its many implications for research and management. However, this apparent simplicity is deceptive, since mangrove species are extraordinarily maIleable in their adaptations to their environ.ment. ln fact, the varied responses of these few species to local patterns of tidal and terrestrial drainage influence led Lugo & Snedaker (1974) to develop a classification system based on the observation that where mangrove stands share similar environ.mental conditions they attain similar leveIs of structural development and function. This accomodation to local conditions results in ahigh diversity Mangrove research in Latin America of forest types in spite of their floristic simplicity, because of the diversity in growing conditions over their geographic We can divide the study of Latin American mangroves range. Even in a given area, microtopographic features into three stages: an early phase consisting of the may be reflected in changes in plant structure. narratives of the flrst visitors to the region (Oviedo, 1526; On a geographic basis New World marigroves attain Souza, 1971) and ofuers, followed by the more detailed their greatest development where rainfall and tidal observations of well known naturallsts from the latter subsidies are large. They develop best in equatorial areas part of the 19th and early 20th centuries such as Eggers influenced by the intense convective activity within the (1892), Schimper (1903) and others who provided the flTst Intertropical Convergence Zone and subjected to detailed scientific accounts of mangrove systems in the mesotidal or macrotidal regimes (tnesotidal 2-4 m, New World. Final1y, in this century we fmd more detailed macrotidal > 4 m; Davies, 1964). These conditions local studies such as the description of the mangroves of (annual rainfall > 2000 mm, tidal amplitudes> 2 m) Santos by Luederwaldt (1919), and Cananéia (Gerlach, occur in the northwest part of the South American 1958) in Brazil, the description of the mangroves of the continent (northern Ecuador, Pacific coast of Colombia Pacific coast of Colombia by West (1956), the review of and southern Panam a) and on the eastern seabord of the mangrove biology by Cuatrecasas (1958), the description continent south of the Gulf of Paria (Venezuela) to São ofEcuadorian mangroves by Acosta-Sotis (1959) and the Luís in BraziL It is in this moist and dynamic region where ecophysiological studies of Pannier (1959, 1962), Pannier the greatest mangrove development occurs. Red & Rodriguez (1967) in Venezuela, and in Brazil by mangrove (Rhizophora) forests attaining 40-50 m in Lamberti (1969). Thom (1967), in bis studies of the height and more than 1 meter in diameter have been mangroves of the Thbasco delta (Mexico), stressed the reported in northern Ecuador (Acosta-Solis, 1959), and importance of physiography and impinging geomorphic in the Pacific coast of Colombia (Lamb, 1959). Another processes on the development of mangrove communities. area of intense dynamism and mangrove development is ln the 1970's, events related to the developing found along the coasts of Suriname, French Guiana and environ.mental movement in the United States and the northern part of Brazi~ north of the inouth of the research by Heald (1969) and Odum (1970) pointing out Amazon. Extraordinarily well developed black mangrove the ecological role of mangroves as sources of organic (Avicennia) forests are typical of this coast. Stands reach matter to estuarine food webs, led to a marked interest in 30 m in height and diameters of 50-70 cm are common at . these systems, their ecology and management. Lugo, the island of Maracá, about 2 degrees· north of the Snedaker and ass<;>ciates produced many important equator (Schaeffer-Novelli et ai., 1988). Interestingly papers related to ecology, productivity, decomposition enough' mangrove development and coverage near the and transport of detritus, papers too numerous to cite here delta of the Amazon river is restricted because of the but well known to mangrove researchers everywhere. SCHAEFFER-NOVELLI & CINTRON: Mangrove research: Status Noteworthy, however, is the review on the ecology of mangroves by Lugo & Snedaker (1974). Pool et aL (1977) made the first comparative structural study of mangrove forests in Florida, Puerto Rico, Mexico and Costa Rica. This interest quickly trickled to the South American region, mainly through the efforts of the UNESCO Regional Office in Latin America (ROSTLAC), which, recognizing theimportance of mangrove research and conservation in the area, sponsored in December 1978 a Symposium on the Scientific Aspects and Human Impact on the Mangrove Ecosystem. Thirty one ·papers were presented in this important symposium (UNESCO/ROSTLAC, 1980). UNESCO/ROSTLAC aIso sponsored the publication of an introduction to mangrove ecology (Cintron & Schaeffer-Novelli, 1983). This publication is in the Spanish language and is directed to students and resource managers in Latin America. It appeared for a while that the recognition of mangroves as valuable resources would result in the sponsorship of vigorous research and the development of plans for sustainable and multi pIe use of mangrove forest resources. This would have contributed to the rational use of a historically abused and poorIy understood resource. Unfortunately this was not to be. The economic recession of the 80's and its impact on funding agencies, both national and international, and changing national priorities have dramatically curtailed scientific research. The lack of external funding has also prevented regional coordination and as a result most of South and Central American countries lack active ongoing res~ch on their mangrove forests. Research throughout the region lacks cohesiveness and coordination. ()grrent research 95 remain unattained. ln support of this regional study, Cintron & Schaeffer-Novelli (1985) reviewed the available structural data for mangroves and described patterns in stand development and relationships between structural and functional characteristics. For the workshop held in Puerto Rico a mangrove methods manual was prepared (Schaeffer-Novelli & Cintron, 1986) for the uniform description of structural parameters in the regional study. This manual is an enlarged version of a chapter previously included in the UNESCO manual on mangrove methodology (Cintron & Schaeffer- Novelli, in UNESCO, 1984). Mangrove systems are complexo Although many studies are available we still do not understand many basic processes, responses and restoration mechanisms. Mangrove projects . in the region must adopt a system leveI approach duly recognizing that ecosystem problems are interdisciplinary and require integration. Long-term studies must be initiated to assess natural and man induced changes as well These studies will require intra and inter institutional linkages and close cooperation among researchers in the region. Certainly some regional mechanism will be needed to provide coordination and avoid duplication of efforts. The UNESCO/COMAR/COSALC project may be an instrument to reach this goal if funding is made available and can be directed to mangrove studies as recommended by the Research and Training Group (RTG) at the COSALC project meeting of November 1982 in Venezuela (UNESCO, 1983b). Similarly; national centers for coordination wi11 be required. ln the report of the seminar organized in Cali, Lugo (iii UNESCO, 1979) suggested the elements of a regional project for research in Latin American mangroves. Ris recommendations are still valid and should be given serious consideration. Research in the regions is now almost total1y Strategy for action supported by local governments and educational institutions. Probably the most active research centers are The alarming rate at which mangroves are being the National Autonomous University ofMexico (UNAM), destroyed in the region requires that prompt actions be and the University of São Paulo (Brazil). ln 1981 the taken to develop a regional program such as the one United Nations Development Programme (UNDP) recommended in the UNESCO Cali meeting, capable of sponsored a project for the characterization of the fostering and supporting ecosystemic research, the mangroves of Venezuela and 'li"inidad. This project, development and compilation of management guidelines catried out by the Ministry of the Environment and and the training of scientific personnel, resource Natural Resources in Venezuela, has been completed managers, and providing for public environmental but remains unpublished ln 'li"inidad, Ramcharan et alo education. The great malleability and accomodation to (1982) prepared an inventory of the coastal wetlands of site factors exhibited by mangroves aeates a requirement ninidad and Tobago. The need for the integrated for management strategies that are site specific. These management of coastal systems in the Caribbean let do guidelines and strategies for effective management of a the organization in 1982 of a workshop on the interactions complex resource can only be developed through between coral reefs, seagrass beds and mangroves research, and only through research can we hope to learn (UNESCO, 1983a). Among the recommendations of this to conserve these valuable coastal resources. workshop is that research efforts must involve the region's scientific resources and must have as one of its goaIs the strengthening of its scientific and management Resumo capability. More recent1y (1984), the Organization of American States supported a regional study in which Os manguezais do Novo Mundo são bem menos ricos Brazil, Suriname, Colombia, Mexico, and the Dominiéan . em espécies vegetais que os do Velho Mundo. Entretanto, Republic participated. As part of this project a training essa simplicidade é apenas aparente, pois as espécies de course was held m Puerto Rico in 1986. However, budget mangue são extraordinariamente maleáveis quanto às suas cuts in the OAS dramatically curtalled the original scope adaptações ao ambiente. Geograficamente, os of this project and its most important objectives wi11 manguezais atingçm seu máximo desenvolvimento Bolm Insto oceanogr., S Paulo, 38(1), 1990 96 estrutural onde os subsídios das precipitações pluviais e das marés são maiores. Essas condições ocorrem na costa NW do Continente Americano e da porção oriental do litoral da Venezuela (Golfo de Paria) até São Luís, no Maranhão (Brasil). O interesse pelo estudo e manejo do ecossistema manguezal ocorrido na década de 1970, destacou a função ecológica do sistema como fonte de matéria orgânica para a cadeia alimentar estuarina. A recessão dos anos 80 marcou uma dramática redução dos fundos para pesquisa, tanto nacionais como internacionais. Atualmente os projetos de pesquisa são sustentados, praticamente, por recursos institucionais locais. As elevadas taxas de destruição dos manguezais na região exigem ações decisivas dos órgãos competentes, incluindo apoio à pesquisa, desenvolvimento de planos de manejo e formação de recursos humanos, além da organização de programas de educação ambiental Essas metas somente serão atingidas através de projetos de pesquisa bem estruturados. LUEDERWALD1: H. 1919. Os manguezaes de Santos. Revta Mus. paul,11:309-408. LUGO, A. E. & SNEDAKER, S. C. 1974. The ecology of mangroves. A. Rev. Ecol. Syst., 5:39-64. ODUM, W. E. 1970. Pathways of energy tlow in a south Florida estuary. PhD. Dissertation. University of Miami. 162 p. OVIEDO, G. F. 1526. Historia general y natural de las indias, islas y tierra f1flDe dei mar oceano. Biblioteca de autores espaiíoles. Madrid, 1959. 7v. PANNIER, F. P. 1959. EI efecto de distintas concentraciones salinas sobre el desarrollo de Rhizophora mangle L. Acta cient. venez., Bot., 10:68-78. _ _,...-_ _ _ _ 1962. Estudio fJSiologico sobre la viviparia de RhipJphora mangle. L. Acta cient. venez., Bot.13:184-197. _~-: References ACOSTA-SOLIS, M. 1959. Los manglares dei Ecuador. Contrnes Inst. ecuat. Cienc. natur., (59):1-82. & RODRIGUEZ, P. 1967. The B-complex inhtbitor and its relation to vivipary in Rhizophora mangte L. Int. Revue ges. Hydrobiol., 52(5):783-792. CINTRON, G. & SCHAEFFER-NOVELLI, Y. 1983. Introducción a la ecologia dei manglar. Montevideo, UNESCO/ROSTlAC. 109 p. POOL, D. J.; SNEDAKER, S. C. & LUGO, A. E. 1m. Structure of mangrove forests in Florida, Puerto Rico, Mexico and Costa Rica. Biotropica, 9:195-212. 1985. Caracteristicas y desarrolloestructural de los manglares de Norte y Sur America. Ciencia interamer., 25(1/4):1-15. RAMCHARAN, E. K.; SOUZA, G. DE & FFRENCH, R. 1982. Inventory of the living resources of coastal wetlands in 'ninidad and 1bbago. Report, parts I and n. Natural Resources Programme. Chaguaramas, Institute of Marine Affairs. 13p.; 58p. _-=-_--;- & CUATRECASAS, J. 1958. Introducción al estudio de los manglares. Bolo Soco Bot. Méx., 23:84-98. DAVIES, J. L. 1964. A morphogenic approach to world shorelines. Z. Geomorph., 8(Mortensen Sonderheft):127-142. SCHAEFFER-NOVELLI, Y. & CINTRON, G. 1986. Guia para estudo de áreas de manguezal; estrutura, função e flora. São Paulo, Caribbean Ecological Research. 150 p. + Apêndice. __~= GERLACH, S. A. 1958. Die Mangrove~i tropischer Küsten als Lebensraum. Z Morph. Okol Tiere., 46:636-730. ____~;SO M. L. D'R. & FALKENBERG, D. de B. 1988. Expedição nacional aos manguezais do Amapá: Dha de Maracá. Relatório técnico ao Conselho Nacional de Desenvolvimento Científico e Tecnológico CNPq. Linhas de Ação em Botânica, Ecossistema Manguezal. 99 p. HEALD, E. J. 1969. The production of organic detritus in a south Florida estuary. PhD. Dissertation. University of Miami. UDp. SCHIMPER, A. F. W. 1903. Plant geography on a physiological basis. Oxford, Oxford University Press. 839 p. EGGERS, H. von. 1892. Die Manglares in Ecuador. Bot. Zbl., 52(2):49-52. lAMB, F. B. 1959. The coastal swamp forest Narina, Colombia. Caribb. Forester, 20:79-89. lAMBERTI, A. 1969. Contribuição ao conhecimento da ecologia das plantas do manguezal de Itanhaém. Bolm Fac. Filos. Ciênc. Univ. S Paulo, (317), Bot. (33):1-317. SO~ G. S. de. 1971. natado descriptivo do Brasil em 1527. Edição castigada pelo estudo e· exame de muitos codice manuscritos existentes no Brasi~ em Portugal, Espanha e França, e acrescentada de alguns comentários por F. A. de Vernhagem. São Paulo, Editora NacionallEDUSP. 389 p. SCHAEFFER-NOVELLI & CINTRON: Mangrove research: Status THOM, B. G. 1967. Mangrove ecology and deitai c geomorphology: 1àbasco, Mexico. J. Ecol., 55:301343. 97 UNESCO. 1984. The mangrove ecosystem: research methods. Monogr. oceanogr. Methodol., U.N., (8):1-251. UNESCO. 1979. The mangrove ecosystem: scientific aspects and human impacto Report of the seminar organized by UNESCO at Cali, Colombia, 27 November-1 December 1978. UNESCO Repts mar. Sei., (9):1-40. UNESCO/ROSTLAC. 1980. Memorias deI Seminario sobre el Estudio aentífico e Impacto Humano en el Ecosystema de Manglares. Montevideo, UNESCO/ROSTLAC. 405p. _____ 19838. Coral reefs, seagrass beds and mangroves: their interactions in the coastal zones of the Canbbean. Report of a workshop held at West Indies LabOratory, Sl Croix, U.S. Vtrgin Islands, May 1982. UNESCO Repts mar. Sei., (23):1-133. WEST, R. C. 1956. Mangrove swamps of the Pacific coast of Colombia. Ann. Ass. Amer. Geogr. 46:98-121. _""""""7_---:-_1983b. CoaStal ecosystems of Latin America and the Caribbean. Objectives, priorities and activities of UNESCO's COMAR project for the Latin Atnerican 8JJ.d Caribbean region. Caracas, Venezuela, 15-19 Novetnber 1982. UNESCO Repts mar. Sei., (24):1-46. (&ceived Ol-Jan.-l990; accepted 27-Sept.-l990)