Biology Centre CAS, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic.
Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic.
Sci Total Environ. 2017 Apr 15;584-585:971-981. doi: 10.1016/j.scitotenv.2017.01.148. Epub 2017 Jan 30.
Ionic and nutrient compositions of throughfall, tributaries and lake outlet were analysed in the Plešné catchment-lake system (an unmanaged mountain forest in Central Europe) from 1997 to 2016. The aim was to evaluate changes in surface water chemistry after natural forest dieback. In the 2004-2008, 93% of the Norway spruce trees were killed by bark beetle outbreak, and all dead biomass remained in the catchment. Forest dieback changed the chemistry of all water fluxes, and the magnitude, timing, and duration of these changes differed for individual water constituents. The most pronounced decreases in throughfall concentrations occurred for K, dissolved organic carbon (DOC), Ca and Mg, i.e. elements mostly originating from canopy leaching, while concentrations of NH and soluble reactive phosphorus (SRP) remained almost unaffected. In tributaries, the most rapid changes were increases in NO, K, H and ionic aluminium (Al) concentrations, while terrestrial export of DOC and P forms started more slowly. Immediately after the forest dieback, increase in NO concentrations was delayed by elevated DOC availability in soils. NO became the dominant anion, with maximum concentrations up to 346μeqL within 5-7years after the bark beetle outbreak, and then started to decrease. Terrestrial exports of Al, K, H, Mg, and Ca accompanied NO leaching, but their trends differed due to their different sources. Elevated losses of SRP, DOC, and dissolved organic nitrogen continued until the end of the study. In the lake, microbial processes significantly decreased concentrations of NO, organic acid anions, H and Al, and confounded the chemical trends observed in tributaries. Our results suggest that terrestrial losses of elements and the deterioration of waters after forest dieback are less pronounced in unmanaged than managed (clear-cut) catchments.
1997 年至 2016 年期间，在 Plešné 集水区-湖泊系统（中欧未管理的山地森林）中分析了穿透雨、支流和湖泊出口的离子和养分组成。目的是评估天然林衰退后地表水化学变化。在 2004-2008 年，93%的挪威云杉树因树皮甲虫爆发而死亡，所有死亡的生物量仍留在集水区内。森林衰退改变了所有水流的化学性质，这些变化的幅度、时间和持续时间因个别水质成分而异。穿透雨浓度下降最明显的是 K、溶解有机碳（DOC）、Ca 和 Mg，即主要来源于树冠淋溶的元素，而 NH 和可溶性反应磷（SRP）浓度几乎没有变化。在支流中，变化最明显的是 NO、K、H 和离子铝（Al）浓度的增加，而 DOC 和 P 形态的陆地输出则较慢开始。在森林衰退后，由于土壤中 DOC 的可用性增加，NO 浓度的增加被延迟。NO 成为主要的阴离子，在树皮甲虫爆发后 5-7 年内，浓度高达 346μeqL，然后开始下降。Al、K、H、Mg 和 Ca 的陆地输出伴随着 NO 的淋溶，但由于其不同的来源，它们的趋势不同。SRP、DOC 和溶解有机氮的损失一直持续到研究结束。在湖中，微生物过程显著降低了 NO、有机酸阴离子、H 和 Al 的浓度，混淆了在支流中观察到的化学趋势。我们的结果表明，与管理（皆伐）集水区相比，未管理（未采伐）集水区的元素陆地损失和森林衰退后水质恶化程度较低。
