Wetland loss is a global concern due to its enormous ecosystem services. Marshland, a typical natural wetland, which is concentrated in the Sanjiang Plain, has undergone dramatic loss in the last several decades. The spatiotemporal changes in marshland were studied based on Landsat images of the Sanjiang Plain from 1980 to 2016 with the land use maps in 1980, 1995, 2000, 2005, 2010, and 2016 using land use dynamic degree and landscape indices. The driving forces of marshland loss, including biophysical factors, socio-economic factors, and land management, were analyzed with boosted regression trees (BRTs) methods. The area of marshland loss was 7372 km2, which accounted for 65.7% of the area of marshland in 1980; however, the paddy field area was expanded by 22,313 km2. The lost marshland was mainly converted to dry farmland (47.5%) and paddy field (47.2%) during 1980–2016. Both the landscape pattern of the study area and marshland became increasingly fragmented. The relatively important factors responsible for marshland loss were biophysical factors, socio-economic factors, and land management, which accounted for 65.2%, 25.5%, and 8.4%, respectively. The most important driving forces with high “relative influence” were “distance to river,” which accounted for 20.6% of the total variance explained. The “relative influence” of potential crop yield and ditch density reached 20.2% and 8.4%, respectively. Significant land use changes have occurred in the Sanjiang Plain over the past 37 years, with characteristics of rapid paddy field expansion and drastic marshland loss. Meanwhile, marshland fragmentation continued to increase. Reclamation was the main reason for the large-scale marshland loss. Biophysical factors influenced the decisions regarding the locations of marshland loss. Moreover, climate factors (i.e., average annual precipitation and average annual temperature) also played an important role in marshland loss. These results can provide helpful knowledge for understanding the patterns and reasons for marshland loss and protecting and managing strategies for wetlands restoration.

中文翻译：

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1980-2016年东北三江平原沼泽地的时空变化及其驱动力

湿地丧失由于其巨大的生态系统服务而成为全球关注的问题。沼泽地是典型的天然湿地，集中在三江平原，在过去的几十年中遭受了巨大的损失。利用1980-1995年三江平原的Landsat影像，结合1980、1995、2000、2005、2010和2016年的土地利用动态图，利用土地利用动态度和景观指数研究了沼泽地的时空变化。使用增强回归树（BRT）方法分析了沼泽地流失的驱动力，包括生物物理因素，社会经济因素和土地管理。湿地损失面积为7372 km2，占1980年湿地面积的65.7％；但是，水田面积增加了22,313平方公里。失去的沼泽地主要转变为旱地（47。5％）和水田（47.2％）（1980-2016年）。研究区和沼泽地的景观格局都变得越来越分散。造成沼泽地流失的相对重要因素是生物物理因素，社会经济因素和土地管理，分别占65.2％，25.5％和8.4％。具有“相对影响力”的最重要驱动力是“到河的距离”，占解释的总方差的20.6％。潜在作物产量和沟渠密度的“相对影响”分别达到20.2％和8.4％。三江平原过去37年来发生了重大的土地利用变化，具有稻田迅速扩张和沼泽化程度急剧下降的特点。同时，沼泽地的碎片化继续增加。开垦是造成沼泽地大规模丧失的主要原因。生物物理因素影响着有关沼泽地流失地点的决定。此外，气候因素（即年平均降水量和年平均温度）在沼泽地流失中也起着重要作用。这些结果可为了解沼泽地流失的方式和原因以及保护和管理湿地恢复的策略提供有用的知识。