Report: «Proofing Coastal Protection Leybucht: Vegetation (1995-2000)”

“Summary: Between 1995/96 and 2000 surveys of approximately 90 permanent areas along 10 transects in the Leybucht were carried out by the Coast Research Centre of the Lower Saxony State Office for Ecology in order to document in the long term possible direct and indirect effects on flora and vegetation through the construction measures “Coastal Protection Leybucht” and to be able to clarify certain questions. For better understanding, a brief description of the investigation area as well as the transects is given at the beginning. With the help of numerical classification and ordination methods, the succession trajectories in the permanent areas are displayed and analysed. It is shown that the salt marshes of the Leybucht are a highly dynamic habitat in which both directed and undirected development processes occur during the investigation period. In addition to the terrain height and associated flooding frequency, agricultural use has a significant influence on the flora and vegetation of the salt marshes. In particular, the effects of the abandonment of agricultural use and grazing expansion are discussed. The task of grazing has so far promoted an extraordinarily rapid succession towards the upper salt meadow in many areas. Vegetation units favoured by grazing declined. This also applies to today’s extensively grazed Buscher Heller. These development processes have not yet been completed. Finally, the further development after set-aside and extensive grazing is estimated subject to further large-scale review.”摘要：1995/96年至2000年间，下萨克森州生态州立办公室海岸研究中心针对莱比赫特（Leybucht）沿岸的10条样带（transects）上的约90个永久样地（permanent areas）开展了调查，旨在长期记录“莱比赫特海岸防护”工程措施对植物区系与植被可能产生的直接与间接影响，并解答相关学术问题。 为便于理解，开篇先对调查区域及样带进行简要说明。借助数值分类（numerical classification）与排序（ordination）方法，对永久样地的植被演替轨迹（succession trajectories）进行呈现与分析。 研究表明，莱比赫特的盐沼（salt marshes）属于高度动态的生境，在调查周期内同时存在定向与无定向的发育过程。除地形高程及对应的淹水频率外，农业利用方式对盐沼植物区系与植被亦具有显著影响。本文重点探讨了农业利用弃置与放牧扩张的效应。 截至目前，放牧举措已推动诸多区域以极快的演替速率向高位盐草甸演进，受放牧偏好的植被单元占比下降，这一现象同样适用于当前实施粗放放牧的布舍勒尔（Buscher Heller）地区。此类发育过程尚未完成。 最后，针对休置（set-aside）与粗放放牧后的进一步发展趋势，本文预估有待后续开展大规模的复核评估。