The LULC simulation data we utilized to create future EN maps was produced by X. Liu et al. (2017), which was conducted at the national level. The reason we apply national-level simulated data to a local area is as follows. Firstly, China has a top-down land use planning system (also known as spatial planning) with five levels. The quantitative objectives in national plans are handed down to county-level plans through provincial and prefectural level plans (Zhong et al., 2014). That means land use patterns of nine cities in WUA are required to reflect relevant upper-level plans, for example, to satisfy the land use quota made by Hubei provincial plans and the national plans. Secondly, there are interdependencies across places so what happens in one region produces effects not only on this location but on other regions (Overman et al., 2010). And the increase of construction land in one place will shift protection pressure on natural ecosystems elsewhere for a sustainable goal. The land use simulation at the national level allocated land resources from a top-down perspective and links land use changes in a region to events taking place in other locations through global simulation. However, the Kappa coefficient of the simulated data in WUA is 0.55 and the overall accuracy is 0.71, which is lower than the statistic value at the national-level data. Although the Kappa between 0.4~0.6 is moderate and at an acceptable level (Appiah et al., 2015; Ding et al., 2013; Ku, 2016), the simulated accuracy of the land use data needs to be improved. Future work on exploring the impact of LULC dynamics on EN will develop based on the high-accuracy simulated data and updating the initial simulated time to 2020, by integrating the impacts of socioeconomic factors, climate change, regional planning, land use policy, etc.

答：我们使用的用于创建未来EN地图的LULC模拟数据由X。刘等人（2017）在全国范围内进行，我们将全国层面的模拟数据应用于局部地区的原因如下：首先，中国拥有自上而下的土地利用规划系统（也称为空间规划），具有五个层次。国家计划中的定量目标通过省级和地级计划，传递到县级计划（Zhong等，2014）。这意味着WUA的九个城市的土地利用模式需要反映相关的上级计划，例如，满足湖北省计划和国家计划制定的土地利用配额。其次，不同地方之间存在相互依赖性，因此发生在一个地区的事情不仅会产生影响，而且会影响其他地区（Overman等，2010）。一个地方建设用地的增加会转移到其他地方的自然生态系统上，以达到可持续的目标。全国层面的土地利用模拟从自上而下的视角分配土地资源，并通过全球模拟将一个地区的土地利用变化与其他地点发生的事件联系起来。然而，WUA中模拟数据的Kappa系数为0.55，总体准确率为0.71，低于全国层面的统计值。虽然0.4~0.6之间的Kappa值为中等水平，且水平可接受（Appiah等，2015;丁等，2013;库，2016），但土地利用数据的模拟准确度仍需要提高。未来的工作将基于高精度的模拟数据，将初始模拟时间更新到2020年，并通过综合考虑社会经济因素、气候变化、区域规划、土地利用政策等影响，探索LULC动态对EN的影响。