Area de Biodiversidad y Conservación, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Tulipán s/n, Móstoles, E-28933 Madrid, Spain.
J Environ Manage. 2010 Mar-Apr;91(4):879-86. doi: 10.1016/j.jenvman.2009.11.004. Epub 2009 Dec 11.
Changes in forested landscapes may have important consequences for ecosystem services and biodiversity conservation. In northern Spain, major changes in land use occurred during the second half of the 20th century, but their impacts on forests have not been quantified. We evaluated the dynamics of landscape and forest distribution patterns between 1957 and 2003 in Fragas do Eume Natural Park (northwestern Spain). We used orthoimages and a set of standard landscape metrics to determine transitions between land cover classes and to examine forest distribution patterns. Eucalypt plantations showed the greatest increase in area (197%) over time. Furthermore, transitions to eucalypt plantations were found in all major land cover classes. Forest showed a net decline of 20% in total area and represented 30% of the landscape area in 2003. Forest losses were mainly due to eucalypt plantations and the building of a water reservoir, while forest gains were due to increases in shrubland, meadows and cultivated fields which had been recolonised. Forest patch size and core area decreased, and edge length increased over time. In turn, increases were obtained in mean distance between forest patches, and in adjacency to eucalypt plantations and to a water reservoir. These results suggest an increase in forest fragmentation from 1957 to 2003, as well as a change in the nature of the habitat surrounding forest patches. This study shows that land use changes, mostly from eucalypt plantation intensification, negatively affected forested habitats, although some regeneration was ongoing through ecological succession from land abandonment.
森林景观的变化可能对生态系统服务和生物多样性保护产生重要影响。在西班牙北部，20 世纪下半叶土地利用发生了重大变化，但这些变化对森林的影响尚未量化。我们评估了 Fragas do Eume 自然公园（西班牙西北部）1957 年至 2003 年间景观和森林分布格局的动态变化。我们使用正射影像和一组标准景观指标来确定土地覆盖类型之间的转变，并研究森林分布模式。桉树种植园的面积增加最多（197%）。此外，所有主要土地覆盖类型都发生了向桉树种植园的转变。森林总面积净减少 20%，2003 年代表景观面积的 30%。森林的减少主要是由于桉树种植园和建造水库，而森林的增加则是由于灌木林、草地和开垦农田的重新出现。随着时间的推移，森林斑块的大小和核心区减少，边缘长度增加。反过来，森林斑块之间的平均距离增加，与桉树种植园和水库的相邻度也增加。这些结果表明，1957 年至 2003 年间森林破碎化程度增加，森林斑块周围生境的性质也发生了变化。本研究表明，土地利用变化（主要是桉树种植园的集约化）对森林生境产生了负面影响，尽管通过土地废弃后的生态演替正在进行一些再生。
