Yang Sheng, Mountrakis Giorgos
Department of Environmental Resources Engineering, State University of New York, College of Environmental Science and Forestry, Syracuse, New York, United States of America.
PLoS One. 2017 Feb 22;12(2):e0171383. doi: 10.1371/journal.pone.0171383. eCollection 2017.
Forests are experiencing significant changes; studying geographic patterns in forests is critical in understanding the impact of forest dynamics to biodiversity, soil erosion, water chemistry and climate. Few studies have examined forest geographic pattern changes other than fragmentation; however, other spatial processes of forest dynamics are of equal importance. Here, we study forest attrition, the complete removal of forest patches, that can result in complete habitat loss, severe decline of population sizes and species richness, and shifts of local and regional environmental conditions. We aim to develop a simple yet insightful proximity-based spatial indicator capturing forest attrition that is independent of spatial scale and boundaries with worldwide application potential. Using this proximity indicator, we evaluate forest attrition across ecoregions, land ownership and urbanization stratifications across continental United States of America. Nationally, the total forest cover loss was approximately 90,400 km2, roughly the size of the state of Maine, constituting a decline of 2.96%. Examining the spatial arrangement of this change the average FAD was 3674m in 1992 and increased by 514m or 14.0% in 2001. Simulations of forest cover loss indicate only a 10m FAD increase suggesting that the observed FAD increase was more than an order of magnitude higher than expected. Furthermore, forest attrition is considerably higher in the western United States, in rural areas and in public lands. Our mathematical model (R2 = 0.93) supports estimation of attrition for a given forest cover. The FAD metric quantifies forest attrition across spatial scales and geographic boundaries and assesses unambiguously changes over time. The metric is applicable to any landscape and offers a new complementary insight on forest landscape patterns from local to global scales, improving future exploration of drivers and repercussions of forest cover changes and supporting more informative management of forest carbon, changing climate and species biodiversity.
森林正在经历重大变化；研究森林的地理格局对于理解森林动态对生物多样性、土壤侵蚀、水化学和气候的影响至关重要。除了森林碎片化之外，很少有研究考察森林地理格局的变化；然而，森林动态的其他空间过程同样重要。在这里，我们研究森林消失，即森林斑块的完全消失，这可能导致栖息地完全丧失、种群数量和物种丰富度严重下降，以及局部和区域环境条件的改变。我们旨在开发一种简单而有洞察力的基于邻近度的空间指标来捕捉森林消失，该指标独立于空间尺度和边界，具有全球应用潜力。使用这个邻近度指标，我们评估了美国大陆不同生态区域、土地所有权和城市化分层的森林消失情况。在全国范围内，森林覆盖总面积损失约90400平方公里，大致相当于缅因州的面积，占比下降了2.96%。审视这一变化的空间布局，1992年平均森林消失距离为3674米，2001年增加了514米，增幅为14.0%。森林覆盖损失模拟表明森林消失距离仅增加10米，这表明观测到的森林消失距离增加比预期高出一个数量级以上。此外，美国西部、农村地区和公共土地的森林消失情况要严重得多。我们的数学模型（R2 = 0.93）支持对给定森林覆盖下的消失情况进行估计。森林消失距离指标量化了不同空间尺度和地理边界的森林消失情况，并明确评估了随时间的变化。该指标适用于任何景观，为从局部到全球尺度的森林景观格局提供了新的补充见解，有助于未来对森林覆盖变化的驱动因素和影响进行更深入的探索，并为森林碳、气候变化和物种生物多样性的更具信息性的管理提供支持。
