东北虎（Panthera tigris altaica）曾广泛分布在中国东北、俄罗斯远东和朝鲜半岛，是亚洲温带森林生态系统中的旗舰物种，在维持森林生态系统功能和健康中扮演着重要的作用。然而，由于受栖息地丧失、猎物缺乏、盗猎等因素的影响，东北虎种群数量锐减，分布区也不断缩小，残存在中俄边境的东北虎小种群已严重超出了其资源承载力，向中国内陆扩散是实现东北虎种群恢复和发展的重要途径。近十几年我国一系列的森林恢复和生物多样性保护措施为东北虎恢复提供了契机，在此背景下识别东北虎豹国家公园东北虎的适宜生境和扩散廊道是东北虎种群恢复的重要基础。 本研究基于MODIS/NDVI数据分析了东北虎豹国家公园2000-2016年植被分布和变化趋势，并通过野外实地调查探究了其驱动因素。利用随机森林模型（RF）、广义线性模型（GLM）、最大熵模型（MaxEnt）和推进式回归树模型（GBM）综合评估了东北虎豹国家公园内东北虎生境适宜性分布，识别了影响东北虎分布的主要环境因子，并通过电流理论模型构建了东北虎扩散廊道，旨在为东北虎生境保护和恢复提供科学依据。研究结果如下： （1）虎豹公园2000-2016年植被覆盖NDVI均值为0.72，96%的地区为中高度覆盖（NDVI >0.6）。近17年，虎豹公园植被呈增加趋势，NDVI显著增加区域占整个研究区的19.44%，显著下降区仅占1.32%。 （2）植被增加区域集中分布在虎豹公园中部和西部地区（汪清林业局与绥阳林业局交界、东京城和春阳镇附近），多为天保工程建设的人工林和公益林。植被退化区主要分布在大的城镇附近（如罗子沟、老黑山、春化镇等），与强烈的人类活动密切相关，包括农田、参地、矿地、道路和放牧疏林等引起的森林消失和质量下降。 （3）组合物种分布模型（Ensemble model）结果显示东北虎最优生境和适宜生境面积约8000 km2，占研究区面积的39%，主要集中分布在研究区东南部的中俄边界区，包括珲春保护区内外-敬信镇大肚川、大盘岭、小盘岭、解放沟-密江三安村、大荒沟林场-地阴沟林场-天桥岭的向阳、西大河、响水林场-穆棱的和平和龙爪林场，面积大小可以承载东北虎的最小种群生存数量；次级生境约6269.75 km2，占比31%，主要分布在适宜生境周边和太平川、万宝湾、青山林场，是东北虎在适宜生境间迁移定居重要的连通区。 （4）影响东北虎分布的主要因子包括猎物梅花鹿的潜在分布、距居民点距离、距道路距离、海拔和NDVI；其中梅花鹿生境适宜性贡献最大，高达47.82%，主要因为东北虎和梅花鹿出现点环境生态位重叠度达0.76，地理空间分布生态位重叠度也较高。 （5）基于电流理论的模拟结果显示岩山、大荒沟、荒沟、金沟岭、兰家、浪溪林场是东北虎扩散最可能通过的地区，天桥岭林业局下辖区东北虎生境连通性很高，密江-大荒沟和地阴沟林场为重要的“脚踏石”生境斑块，它们是东北虎从珲春和老爷岭中俄边境地区向中国内陆扩散最重要的停留区。识别的3条东北虎优先扩散廊道分别为三岔河-暖泉河-园山-太平川-万宝湾-向阳林场，兰家-大北城-杜荒子-浪溪-地阴沟-新开-桦皮林场，荒沟-大荒沟-沙金沟-塔子沟-小东沟林场。综上所述，通过生境和猎物恢复、廊道建设和跨境保护促进东北虎栖息地的完整性保护, 是加强该区域东北虎及猎物栖息地保护的关键措施。

Amur tiger (Panthera tigris altaica), a flagship species of the temperate forest ecosystem in Northeast Asia, once widely distributed in Northeast China, Russia Far East and North Korea, playing a vital role in maintaining ecosystem function. However, habitat loss, prey scarcity and poaching have dramatically reduced tiger population size and geographic range. The small population remaining in the Sino-Russian border has exceeded its resource carrying capacity seriously and the ultimate fate of Amur tiger depends on whether they can settle in their historical range in Northeast China. Recently, series of forest rehabilitation and biodiversity conservation measures have developed in China, which provided an opportunity for the recovery of Amur tiger. In this context, it is important to identify and protect the suitable habitat and corridors in the Northeast Tiger and Leopard National Park (TLNP). We analyzed the vegetation cover change from 2000 to 2016 based on MODIS/NDVI data and explored the driving factors through the field survey. Then, we evaluated the habitat suitability distribution of the Amur tiger in TLNP using the ensemble species distribution models (including random forest model, generalized linear model, maximum entropy model and generalized boosted regression model). Finally, we constructed corridors through the circuit theory model, aiming to provide a scientific basis for habitat protection and restoration of Amur tiger. The main results of this study are as follows: (1) From 2000 to 2016, average NDVI is 0.72 over the study area and 96% of the area is covered by NDVI >0.6. Vegetation showed an increasing trend during the past 17 years; NDVI significantly decreased and increased area accounted for 1.32% and 19.44% of the total area, respectively. (2) Vegetation increased areas are mainly located in the central and western areas of TLNP, mostly for natural forest protection project. Vegetation degradation areas are mainly located around big towns (including Luozigou, Laoheishan, Chunhua town, et al) which closely related to human activities, including farmland, ginseng field, mines, roads and grazing. (3) Ensemble model show that the optimal and suitable habitat area for Amur tiger is about 8000 km2 and locate in Southeast region, accounting for 39% of the study area. The marginal habitat is 6269.75 km2, accounting for 31%. They are located in suitable habitat surroundings and Taipingchuan-Wanbaowan-Qingshan forestry bureau, which are important connected areas for Amur tiger to migrate between suitable habitats. (4) The potential distribution of sika deer, distance to settlement, distance to road, elevation and NDVI are main factors that influence Amur tiger distribution, especially sika deer contributing to 47.82%. The overlap of environmental niche between Amur tiger and sika deer is 0.76 and the overlap of geospatial spatial niche is also high. (5) Circuit theory model show that, Amur tiger are most likely to migrate through Yanshan, Dahuanggou, Huanggou, Jingouling, Lanjia and Langxi forest bureau. The connectivity in Tianqiaoling is very high. Mijiang-Dahuanggou and Diyingou forest bureau are important “foot stone” habitat patches. In addition, we identified three priority migration corridors for Amur tiger: Sanchahe –Nuanquanhe –Yuanshan –Taipingchuan –Wanbaowan -Xiangyang, Lanjia –Dabeicheng –Duhuangzi –Langxi –Diyingou–Xinkai-Huapi, Huanggou -Dahuanggou -Shajingou -Tazigou -Xiaodonggou. Promoting the integrity of Amur tiger habitat through habitat and prey restoration, corridor construction and cross-border protection is a key measure to strengthen the protection of Amur tiger and its prey habitat in the region.