기후변화가 생태계에 미치는 영향 고찰

Abstract

The Impact of Climate Change on the Ecosystem : The Case of Wetland Plants This study was carried out to provide preliminary information for researchabout the impact of future climate changes on the wetland ecosystem. The information was collected by reviewing articles on the impact of climate change as well as by surveying flora and vegetation in an abandoned paddy field, de facto a type of wetland, and particularly in terraced fields. The study reviewed published articles and books to collect information on the impact of climate change on plants in the wetland ecosystem and also to investigate vegetation in both quadrant areas and each terrace of the abandoned paddy field to reflect if there is any impact on wetland plants or any visible vegetation pattern due to potential climatic changes. The reason that the wetland ecosystemwas selected was because ofits comparatively sensitive response to climate change compared to other ecosystems.Likewise, abandoned paddy fields were selected because they have among the most sensitive response to climate compared to other wetlands. We focused on vegetation because wetland plants are known to react more strongly to changes in the environment compared to other groups and also because they are the primary source of ecological chain responses which provide necessary prey and habitats to other living creatures. A wetland is a place that is constantly or transiently covered by fresh water or brackish water or salt water naturally or unnaturally. Wetlands are categorized as inland wetlands, brackish wetlands, shoreline wetlands, and man-made wetlands. The abandoned paddy field wetland, if formed naturally, is an inland marsh which is subject to fresh water and mostly located in mountainous terraced areas, in which diverse animals (mammals, birds, amphibians and reptiles, insects, aquatic animals) live without human interference so that indigenous and endangered species that need to be protected can be found frequently. The potential impact of climate on wetlands generally follows, 1) lowering of water level and dryness, 2) changes in the hydrological cycle (wet and dry seasons), 3) increments of carbon dioxide, 4) rising sea water levels and salinity, 5) changes in temperature, 6) climate change according to altitude, 7) climate coupled with nutrition, 8) climate combined with human activity. Because the flora living in an abandoned paddy field is mostly dependent on rain and/or underground water, both precipitation and temperature are important climate factors affecting hydrological systems and therebysuccession of vegetation in the wetland. Yearly patterns of both precipitation and temperature are similar, but these are generally high during July through September in Korea. In order to find any relationship between climate factors and vegetation composition in an abandoned paddy field, vegetation distribution,and plant composition were investigated in five survey areas selected in different latitudes of different provinces. The current vegetations and habitat conditions may reflect climate impacts in the past. However, any particular relationship could not be discovered probably due to the short study period and insufficient study areas. There may not be distinct differences in the vegetation distribution because the climate zone in South Korea shows little differences. In fact there was not much difference in the pattern of monthly average precipitation and temperature for 10 years in five weather stations. But the range of fluctuation of yearly precipitation was wider in the southern provinces than the northern provinces, and winter temperature did not go down below zero in the south, but did in the north. Further research will be required to resolve questions if any relationship is present between the pattern of climate and the distribution of vegetation in the wetland. A hydrological system seemed to be the most important factor to affect mostly the distribution and succession of vegetation in abandoned paddy fields. The time to form the wetland may not be a factor. In other words the species and the distribution of wetland plants were divergent according to the supply system of water, the preservation period of water, and the depth of water, etc. Submerged or floating-leaves or floating plants lived in regions where water was continuously supplied all year. Emergent plants were found in the region where water was periodically supplied. Other wetland-preferred plants lived in regions where water was occasionally supplied. Upland or terrestrial plants occupied the boundary of the abandoned paddy field. It may not be easy to predict for certain how the climate will change in the future. If yearly precipitation decreases and dryness due to global warming continues, it will be possible that the wetland ecosystem will be changed to a terrestrial ecosystem. According to the result, the number of wetlands will decrease, causing the pattern of vegetation to change and causing diverse biotic creatures and species to disappear. Certain measures are necessary to cope with such changes. It is the dominant opinion that climate change has been caused by human activities. The most significant potential impact on the vegetation of wetlands is replacement by inland species according to dryness of the habitat, which is faster than natural processes. Because this impact is not a natural process, the spread of the impact to the ecosystem will be fast and profound. Especially in protected areas, a place for habitat and a corridor for rare and endangered species must be managed and maintained. Protection measures are needed to prepare hydrological systems against abrupt climate change. The best method is to maintain the current status of wetlands without damage from construction and development. The reason is that the life-cycle of most plants and animals interrelate like the teeth of a gear, and are also sensitive to alteration of the climate and environment, causing a series of effects to spread and grow compared to natural processes. Although this study is a preliminary one-year work, detailed information will be obtained through further research. The results and information from continuous studies will be put to practical use for policy to preserve the wetland ecosystem and repair biodiversity altered by climate change and human impact.