Labilidad de los ecosistemas terrestres fuego- patagónicos
Cargando...
Fecha
1989
Autores
Título de la revista
ISSN de la revista
Título del volumen
Editor
Resumen
Como una de las consecuencias de las glaciaciones pleistocénicas y de sus reavances en el Tardiglacial, los substratos en que se encuentran establecidos los ecosistemas terrestres fuego-patagónicos se consideran geológicamente recientes y por lo tanto, son comunes suelos aun inmaduros o en estados tempranos de desarrollo. Por otra parte, un porcentaje significativo de su flora vascular pertenece a elementos fitogeográficos inmigrantes de otras latitudes, por lo que para muchas especies las condiciones climáticas y el fotoperíodo del área se encuentran más cercanos a sus límites inferiores de tolerancia que a los óptimos, para enfrentar los efectos de los factores físicos que caracterizan sus hábitats. Los efectos selectivos de los cambios climáticos recurrentes, desarrollados desde hace aproximadamente 16.000 años, al normalizarse el clima después del Tardiglacial, han determinado que los ecosistemas actuales estén conformados por pocas especies, ya que varias de las inmigrantes potenciales no encontraron condiciones mesológicas favorables o fueron eliminadas del área durante sus procesos migracionales, al presentarse episodios climáticos desfavorables para su supervivencia. Las fluctuantes temperaturas, durante el postglacial, iniciaron el desarrollo de un paulatino proceso
de aridificación climática, manifestado en cambios en la composición florística de las comunidades vegetales y en el condicionamiento de sus rutas de desplazamiento, siguiendo aquellas de los tipos climáticos. Estos factores determinan que los ecosistemas terrestres presenten un bajo nivel de homeostasis, lo que los hace extremadamente susceptibles a sufrir procesos, a veces irreversibles, de deterioro al ser expuestos a alteraciones exógenas, por lo que su utilización económica y manejo exigen gran cuidado y la adopción de precauciones especiales, basadas en información con una amplia cobertura ambiental.
As one of the consequences of the Pleistocene glaciations and their Lateglacial readvances, the substrata in which the Fuego-Patagonian terrestrial ecosystems are established are considered as geologically young, having thus many soils still immature or in early stages of development. A significant percentage of the vascular flora belongs to phytogeographical elements for which the climatic conditions and the photoperiod of the area are much closer to the lower tolerance limits than to the optima for withstanding the effects of the physical factors characterizing their habitats. The selective effects of recurrent climatic changes developed during the past 16,000 years following the last glacial recession, determined that the present day ecosystems are made up of few species, since several of the potential immigrants did not find favourable environmental conditions for their establishment or were eliminated from the arca during unfavourable climatic episodes. The fluctuating temperatures, during the Postglacial, started the development of a climatic aridification process, shown in changes in the floristic composition of the plant communities and in the conditioning of their displacement routes following those of the climatic types. These factors determine a low level of homeostasis in terrestrial ecosystems, which makes them extremely susceptible to deterioration processes, sometimes irreversible, when exposed to exogenous alterations, thus their exonomic utilization and management require great care and the adoption of special precautions based on information having an ample environmental coberture.
As one of the consequences of the Pleistocene glaciations and their Lateglacial readvances, the substrata in which the Fuego-Patagonian terrestrial ecosystems are established are considered as geologically young, having thus many soils still immature or in early stages of development. A significant percentage of the vascular flora belongs to phytogeographical elements for which the climatic conditions and the photoperiod of the area are much closer to the lower tolerance limits than to the optima for withstanding the effects of the physical factors characterizing their habitats. The selective effects of recurrent climatic changes developed during the past 16,000 years following the last glacial recession, determined that the present day ecosystems are made up of few species, since several of the potential immigrants did not find favourable environmental conditions for their establishment or were eliminated from the arca during unfavourable climatic episodes. The fluctuating temperatures, during the Postglacial, started the development of a climatic aridification process, shown in changes in the floristic composition of the plant communities and in the conditioning of their displacement routes following those of the climatic types. These factors determine a low level of homeostasis in terrestrial ecosystems, which makes them extremely susceptible to deterioration processes, sometimes irreversible, when exposed to exogenous alterations, thus their exonomic utilization and management require great care and the adoption of special precautions based on information having an ample environmental coberture.
Descripción
Palabras clave
Ecosistemas terrestres, Homeostasis, Cambio climático, Ecología
Citación
Anales del Instituto de la Patagonia, Vol. 19, n°1, pp. 17-25, 1989-90