Conservation of Water Environment and Vegetation in Mire

本研究旨在评估人类活动对沼泽地地下水水质及沼泽地植被的影响，如水耕制度的改变，并提出沼泽地的保育制度。我们选择了典型的Sarobetsu Mire和Kiritappu Mire。以北海道的沼泽为研究对象。从1997年到1998年，我们调查了Sarobetsu 7次，Kiritappu 6卷。二次大战后，由于排水和修建农田，左别沼泽的植被遭到破坏，其余沼泽因萨萨的入侵而面临生存的危险。Kritappu Mire的变化与Sarobetsu Mire的变化相似。研究了沼泽地及周边地区的地下水、河流湖泊水质、土壤成分及泥炭藓和白竹的生长状况。根据这些数据，我们发现人类活动影响着沼泽的生命。结果表明，沼泽地排水使地下水位下降，泥炭土变干，泥炭土分解使养分富集，开发混土使磷和草酸含量增加。成分的变化似乎影响植物的生长状态。在左别沼泽中，排水作用导致赤竹入侵，泥炭土分解增加无机养分，促进赤竹生长。要抑制以莎莎为代表的异质植物进入沼泽，必须防止沼泽外物质的侵入。

This study is to estimate the influences of human activities to ground water quality and vegetation of mire, such as changes of water cultivation system and to propose the conservation system of mire. We chose Sarobetsu Mire and Kiritappu Mire, typical. mire of Hokkaido as subjects of the study. We surveyed Sarobetsu 7 times and Kiritappu 6 tomes from 1997 to 1998. Vegetation of Sarobetsu Mire has been destroyed .by draining and building farmland after World War II, and the rest of mire is in peril of existence by invasion of Sasa. Kritappu Mire is changing in similar course of development as Sarobetsu Mire. We researched water quality of ground water, rivers and lakes of the mire and surrounding area, soil composition and growing state of Sphagnum and Sasa. According to the data, we found that human activities affects life of mire. We found that by draining water from mire, ground water level lowers and peat soil gets dry, concentration of nutrients arises by decomposition of peat soil, and mixing soil by exploitation increases amount of phosphorus and silicic acid. The change of composition seems to influence the growing state of plants. In Sarobetsu Mire, drainage leads Sasa to invade causing increase of inorganic nutrients as peat soil decomposes, and promote Sasa to grow. It is necessary to check matters to invade from outside of mire in order to restrain heterogeneous plants as Sasa as a typical one to get into mire.