Vegetation and rejuvenation after disturbance events (wind throw, bark beetle infestation) in spruce age-class populations in the Gesäuse National Park

In recent years there has been a strong spread of the bark beetle species Yps typographus in spruce stocks in the area of the Scheuchegg alm. The most intense infestation occurred in 2009 and 2010. In a national park, dead wood was supposed to remain in the stock and so spruce from which the bark beetles had already flew out were also left in the area of the mentioned bark beetle infestation (called young open space). However, these remaining standing deadwood logs account for only a small part of the total wood volume of the disturbance area. The larger proportion was removed. The release of the beetle broods was considered too risky for the spruce populations in the surrounding area. Due to the location on the edge of the national park, economic forests outside the park would also have been endangered. A debarkation of tribes, such as partially accomplished elsewhere in the national park, was completely renounced here. As an argument for this, the Department of Forest and Wildlife Management mentioned on the one hand the cost pressure, on the other hand, there was concern that the barked tribes would slip and endanger infrastructure below. For these reasons, most of the timber volume was removed and sold in summer 2010 and early summer 2011. For this purpose, it can be noted that in many nature conservation reserves with process nature conservation orientation, whose area sizes only reach the lower limit for large protected areas, buffer zones for the control of the book printer (Yps typographus) are already established outside the protected area. For the Gesäuse National Park, the purchase of the Waag area (neighboring economic area at Scheuchegg) was already argued in the planning phase with the creation of such a buffer zone. The future implementation of this project would be very welcome to nature conservation. In this thesis, the above-mentioned young open space is first documented in terms of its extent and current vegetation. This characterisation is primarily intended to serve as a basis for interpretation of vegetation development for future ascents or monitoring recordings. It can be anticipated that the observation of the open space is recommended in the future, as currently tree species or shrub species rejuvenation is completely lacking. Forest clearing corridors and bushes are among the particularly insufficiently studied biotope types of Central Europe (see e.g. WEBER 1999, EXNER & WILLNER 2007); subalpin even more than montan or collin, as turned out in the course of the research on this text. In order to make a small contribution to closing this knowledge gap in general, as well as to provide indications for the expected vegetation development of the young open space, the second part of the report is devoted to the vegetation and rejuvenation conditions of older forest clearing corridors in the southwestern environment of the Scheuchegg-Alm.近年来，肖伊希格阿尔姆（Scheuchegg alm）区域内的云杉林分遭受了树皮甲虫（Yps typographus）的大规模扩散危害。该虫害最严重的暴发时段为2009年与2010年。在某国家公园内，按照规程需保留林分中的枯木，因此已被树皮甲虫羽化迁出的云杉也被留存于上述虫害发生区域（该区域被称为幼龄裸露空地）。但这些留存的立枯木仅占该扰动区域总木材蓄积量的极小部分，绝大部分枯木已被移除。任由甲虫幼虫发育羽化会对周边区域的云杉种群造成极高的扩散风险。加之该区域位于国家公园边缘，公园外的商品林也将面临虫害威胁。此前该国家公园其他区域曾部分实施过的树干剥皮处理方案，在此被完全否决。森林与野生动物管理部门就此给出两点理由：其一为成本压力；其二则担忧剥皮后的树干发生倒伏，危及下方的基础设施。基于上述原因，该区域绝大多数木材蓄积量于2010年夏季及2011年初夏被移除并售卖。 就此背景而言，诸多以生态过程保护为导向的自然保护地，其面积仅达到大型保护地的下限阈值，此类保护地已在保护区外围设立了针对树皮甲虫（Yps typographus）防控的缓冲区。就格塞国家公园（Gesäuse National Park）而言，其在规划阶段便以设立此类缓冲区为由，申请收购毗邻肖伊希格阿尔姆的瓦格经济林区（Waag area）。该项目的未来落地将对自然保护事业大有裨益。 本研究首先对上述幼龄裸露空地的范围及现状植被进行了记录与表征，该表征工作主要为后续野外考察或监测记录中的植被演替分析提供基础依据。鉴于当前该区域完全缺乏乔木及灌木的天然更新现象，未来仍需持续对该裸露空地开展观测工作。 森林采伐迹地廊道与灌丛是中欧地区研究程度极低的生境类型之一（参见WEBER 1999、EXNER & WILLNER 2007）；本研究过程中发现，亚高山带的该类生境研究程度甚至低于山地带与丘陵带。为填补该领域的研究空白，同时为该幼龄裸露空地的植被演替预测提供参考依据，本报告第二部分聚焦于肖伊希格阿尔姆西南区域内的成熟森林采伐迹地廊道的植被与天然更新状况。