Ecosystem-level properties of the Luquillo Experimental Forest with emphasis on the Tabonuco forest
Forest structure and dynamics in the Luquillo Experimental Forest (LEF) are organized along an altitudinal gradient that reflects atmospheric, edaphic, and topographic conditions in the Luquillo Mountains. Global circulation drives atmospheric conditions in the LEF. In spite of its favorable tropical climate, the environment in the LEF has periods of considerable stress associated with storms and hurricanes. These events trigger landslides and periods of massive sudden tree mortality that greatly influence conditions for forest growth and succession. The main abiotic conditions that stress the biota are: (1) mechanical stress imposed by heavy winds and rains, (2) strong leaching of all surfaces by nearly pure waters with high chemical potential, (3) unstable terrain subject to mass movements on which plants must anchor and grow, and (4) saturated and anaerobic soils. Fourteen biotic responses to these abiotic challenges are discussed. These are: (1) smooth forest canopies, (2) episodic tree mortality, (3) size and age dominance among tree populations, (4) high diversity of life forms, (5) interception and retention of nutrients by epiphytes and other specialized life forms, (6) high interception of water, (7) formation of tree unions and morphological or growth plasticity, (8) modification of microtopography by tree, (9) overriding importance of certain groups of organisms, (10) high turnover of species in microscales, (11) heterophylly and sun and shade light adaptation, (12) high root density, root biomass, and turnover of fine roots, (13) high turnover of nutrients and organic matter as a result of root and vegetation dynamics, and (14) constancy of ecosystem rate processes in mature stands. Because of disturbances and the high rainfall, biotic control over nutrient cycles and organic matter turnover appears critical. We identify five main interfaces where the biota controls these parameters, forming the basis for resiliency of forest ecosystems in the LEF. These interfaces and their key biotic controls are: (1) atmosphere-terrestrial interface dominated by epiphytes and atmospheric fungi, (2) soil-aboveground interface dominated by microorganisms and animals such as earthworms, (3) plant-soil interface dominated by woody vascular plants and animal populations such as termites, (4) terrestrial-aquatic interface dominated by a large array of aquatic and amphibian species of plants and animal, and (5) the aerobic anaerobic interface dominated by bacteria and fungi.
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| Format: | biblioteca |
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New York, NY (EUA) Springer-Verlag
1995
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| Subjects: | CARACTERISTICAS DEL SITIO, FENOMENOS ATMOSFERICOS, DOSEL, MORTALIDAD, ESPECIES DOMINANTES, DINAMICA DE LA POBLACION, NUTRIENTES, MATERIA ORGANICA, PRODUCCION DE BIOMASA, ESTRUCTURA DEL BOSQUE, PUERTO RICO, |
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| Summary: | Forest structure and dynamics in the Luquillo Experimental Forest (LEF) are organized along an altitudinal gradient that reflects atmospheric, edaphic, and topographic conditions in the Luquillo Mountains. Global circulation drives atmospheric conditions in the LEF. In spite of its favorable tropical climate, the environment in the LEF has periods of considerable stress associated with storms and hurricanes. These events trigger landslides and periods of massive sudden tree mortality that greatly influence conditions for forest growth and succession. The main abiotic conditions that stress the biota are: (1) mechanical stress imposed by heavy winds and rains, (2) strong leaching of all surfaces by nearly pure waters with high chemical potential, (3) unstable terrain subject to mass movements on which plants must anchor and grow, and (4) saturated and anaerobic soils. Fourteen biotic responses to these abiotic challenges are discussed. These are: (1) smooth forest canopies, (2) episodic tree mortality, (3) size and age dominance among tree populations, (4) high diversity of life forms, (5) interception and retention of nutrients by epiphytes and other specialized life forms, (6) high interception of water, (7) formation of tree unions and morphological or growth plasticity, (8) modification of microtopography by tree, (9) overriding importance of certain groups of organisms, (10) high turnover of species in microscales, (11) heterophylly and sun and shade light adaptation, (12) high root density, root biomass, and turnover of fine roots, (13) high turnover of nutrients and organic matter as a result of root and vegetation dynamics, and (14) constancy of ecosystem rate processes in mature stands. Because of disturbances and the high rainfall, biotic control over nutrient cycles and organic matter turnover appears critical. We identify five main interfaces where the biota controls these parameters, forming the basis for resiliency of forest ecosystems in the LEF. These interfaces and their key biotic controls are: (1) atmosphere-terrestrial interface dominated by epiphytes and atmospheric fungi, (2) soil-aboveground interface dominated by microorganisms and animals such as earthworms, (3) plant-soil interface dominated by woody vascular plants and animal populations such as termites, (4) terrestrial-aquatic interface dominated by a large array of aquatic and amphibian species of plants and animal, and (5) the aerobic anaerobic interface dominated by bacteria and fungi. |
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