Effects of climatic conditions on morphology, hydrochemical conditions, and plant species composition of Sphagnum hummocks

为了阐明整个北海道泥炭藓丘形状和大小区域差异的原因，我们在控制雪压和其他植物遮荫的条件下，检查了生长在4个沼泽丘上的3种泥炭藓的生长情况。富士川有圆柱形和极高的类型，Sarobetsu和Utasai有平坦和低的类型。Utonai为圆锥形和中等高度型，Sarobetu和Utasai年生长量较大。显著抑制了S.在Sarobetu的papillosum在6月观察到，由于最高的蒸散量和缺乏雨水，那里的丘表面干燥。遮荫的去除抑制泥炭藓的生长在所有沼泽，可能是由于从丘表面蒸发蒸腾量的增加损失。雪压的消除导致了深雪区Sarobetu和Utasai第二年夏季生长的减少，因为丘表面保持足够高， ...更多信息 我们调查了富士川沼泽中一个隆起的泥炭藓丘的水分平衡，并考虑了水分是如何在丘内移动的。在晴天，表层通过补充下层蒸散损失的相同水量来保持恒定的含水量，但由于深层供水不足，下层的含水量正在减少。降雨时，来自丘体表面的雨水通过表层迅速蒸发，没有储存，但有部分雨水储存在深层。表层完整泥炭结构精细，保水、吸水能力强。因此，当一些水从表层蒸发蒸腾损失，水能够从更深的层补充。与此相反，它似乎是中度分解泥炭与宏观结构的崩溃在较深的层具有相对较低的导水率，导致在较深的层在良好的时期和降雨期间的雨水储存的含水量减少。雨水的储存机制会在微营养化地表水上的内丘处产生富营养化条件。此外，整个生长季节的潮湿气候条件，如降雨频繁，间隔时间短，净水损失的负值大，阻止了深层含水量的下降和下垫水面的降低。少

In order to clarify the reasons of regional differences in shape and size of Sphagnum hummocks throughout Hokkaido, we examined the growth of 3 Sphagnum species growing on hummocks in 4 mires, with controlling the conditions of snow pressure and shading by other plants. Fuhrengawa has cylindrical and extremely raised type, Sarobetsu and Utasai have flat and low type. Utonai has conical and middle height type, The annual growth was larger in Sarobetu and Utasai. Remarkable suppression of the growth of S. papillosum at Sarobetu was observed in June, where hummock surface was desiccated owing to the highest evapotranspiration and a lack of rainwater. Removal of shading suppressed the growth of Sphagnum in the all mires, probably due to the enhanced evapotranspiration losses from hummock surface. Removal of snow pressure caused the decrease in the growth of next summer at Sarobetu and Utasai in deep snow region, because hummock surface were kept higher enough from underlying water table to … More suffer severe drought.We investigated the water balance of a raised hummock of Sphagnum fuscum in Fuhrengawa mire and consider how water moves interior hummock. In fine days, a surface layer kept a constant water content by re-supplying the same amount of water lost by evapotranspiration from a lower layer, but water content in the lower layer was decreasing because of an insufficient supply of water from deeper parts. When it was raining, rainwater supplied from the hummock surface percolated rapidly through the surface layer without storage, whereas some rainwater was stored into the deeper layer. Intact peat of surface layer has fine structure resulting high water retention and absorption capacity. Therefore, when some water was lost from the surface layer by evapotranspiration, water was able to re-supplied from the deeper layer. Contrary to this, it seemed that moderately decomposed peat with macrostructural collapse in deeper layer has relatively low hydraulic conductivity, resulting in decreasing water content during fine periods and storage of rainwater during rain periods in the deeper layer. The storage mechanism of rainwater would generate an ombrotrophic condition at inner hummocks standing on minerotrophic surface water. Furthermore, the humid climatic conditions throughout a growing season such as frequent rains with short intervals and large negative values of net water loss prevent from declining water content of the deeper layer and decreasing the level of underlying water surface. Less