Schaich Harald, Kizos Thanasis, Schneider Stefan, Plieninger Tobias
Department of Environmental Planning, Landscape Ecology and Nature Conservation, Environmental Protection Agency, City of Freiburg, Talstr. 4, 79102, Freiburg, Germany,
Environ Manage. 2015 Jul;56(1):110-26. doi: 10.1007/s00267-015-0496-y. Epub 2015 Apr 16.
In Mediterranean Europe, wood-pasture landscapes with oak woodlands as emblematic ecosystems are undergoing rapid land-use change, which may threaten their legacy as hotspots of biodiversity, ecosystem services, and cultural heritage. The objective of this study was to quantify land cover changes and transitions as well as the dynamics of oak woodland patterns and densities over 50 years in two municipalities at the center and edges of Quercus macrolepis distribution in Northern Lesvos (Greece). We used aerial photographs from 1960 and WorldView-2 satellite images from 2010 to process land cover maps and metrics, and to calculate oak canopy cover with a point-grid sampling approach. Spatiotemporal dynamics of land cover change were generally high--especially between oak woodlands and grass- and shrub-lands, resulting in a more heterogeneous and fragmented landscape in 2010. Surprisingly, oak woodland area remained stable with marginal losses in one study site and gains in the other one. Oak canopy cover increased by 8 and 9%. Spatial hotspots of change were mountainous and peripheral phrygana areas with expanding oak stands, as well as river valleys and near urban areas with expanding olive groves and grass- and shrublands in former complex cultivation and oak stands. We conclude that the parallel processes of abandonment of crop cultivation and intensification of livestock grazing have been less detrimental to oak woodlands than supposed. To ensure long-term persistence of oak woodlands in the face of ongoing rural depopulation and land-use intensification, environmental and agricultural policies should better address their specificities as anthropogenic habitats.
在地中海欧洲地区，以橡树林地作为标志性生态系统的林牧景观正在经历快速的土地利用变化，这可能会威胁到其作为生物多样性、生态系统服务和文化遗产热点地区的地位。本研究的目的是量化希腊莱斯博斯岛北部大果栎分布中心和边缘的两个市镇在50年里的土地覆盖变化与转换，以及橡树林地格局和密度的动态变化。我们利用1960年的航空照片和2010年的WorldView-2卫星图像来处理土地覆盖图和指标，并采用点网格抽样方法计算橡树树冠覆盖率。土地覆盖变化的时空动态总体较高，尤其是在橡树林地与草地和灌木地之间，导致2010年的景观更加异质化和碎片化。令人惊讶的是，橡树林地面积保持稳定，在一个研究地点略有减少，而在另一个地点有所增加。橡树树冠覆盖率分别增加了8%和9%。变化的空间热点是山区和周边的弗里干纳地区，那里的橡树林在扩张，以及河谷和城市附近地区，那里的橄榄林以及草地和灌木地在原复杂种植区和橡树林中不断扩张。我们得出的结论是，作物种植废弃和牲畜放牧集约化这两个并行过程对橡树林地的危害比预期的要小。为了确保橡树林地在农村人口持续减少和土地利用集约化的情况下长期存续，环境和农业政策应更好地考虑其作为人为栖息地的特殊性。
