The Effects of Land-Use Change/Conversion on Trade-Offs of Ecosystem Services in Three Precipitation Zones

Abstract

Revealing the spatial differentiation of ecosystem service (ES) trade-offs and their responses to land-use change along precipitation gradients are important issues in the Loess Plateau of China. We selected three watersheds called Dianshi (300 mm < MAP (mean annual precipitation) < 400 mm), Ansai (400 mm < MAP < 500 mm), and Linzhen (500 mm < MAP < 600 mm). A new ES trade-off quantification index was proposed, and quantile regression, piecewise linear regression, and redundancy analysis were used. The results were as follows. (1) Carbon sequestration (TC) and soil conservation (SEC) increased, but water yield (WY) decreased in the three watersheds from 2000 to 2018. (2) The effect of forests on trade-offs was positive in three watersheds, the main effect of shrubs was also positive, but the negative effect appeared in the TC-WY trade-off in Ansai. Grassland exacerbated trade-offs in Dianshi, whereas it reduced trade-offs in Ansai and Linzhen. These effects exhibited respective trends with the quantile in the three watersheds. (3) There were threshold values that trade-offs responded to land-use changes, and we could design land-use conversion types to balance ESs. In general, the water consumption of grass cannot be ignored in Dianshi; shrubs and grass are suitable vegetation types, and forests need to be restricted in Ansai; more forests and shrubs can be supported in Linzen due to higher precipitation, but the current proportions of forests and shrubs are too high. Our research contributes to a better understanding of the response mechanisms of ES trade-offs to land-use changes.

Characteristics and Estimation of Dew in the Loess Hilly Region of Northern Shaanxi Province, China

“…In addition, the frost-free period is approximately 157 d, the annual potential evaporation is 1010-1400 mm [41], and the sunshine hours are 2396 h•a −1 [42]. The vegetation types are primarily herbaceous communities and thickets, and the common plants include Robinia, Pinus tabulaeformis, Caragana korshinskii, and sea buckthorn [7,43].…”

The Large-Scale Effect of Forest Cover on Long-Term Streamflow Variations in Mediterranean Catchments of Central Chile

“…The forest cover percent (see Equation ( 1)) was calculated for each of the 42 catchments under evaluation using Equation (1), where F C is the forest cover (%) estimated using the first and last year of available data for each catchment; A F is the area of total forest cover (including native forests and/or forest plantations) (m 2 ); and A C is the area of the catchment under analysis (m 2 ). All 42 catchments were classified according to their F C value, resulting in 24 categories (groups) shown in Table 2.…”

“…A key challenge faced by forest managers is how to maximize the wide variety of benefits generated from forest ecosystems without impacting the availability of water resources over time. For instance, forest ecosystems play a crucial role on the mitigation of global warming through carbon sequestration (e.g., [1]). Large-scale forest disruption has been correlated to adverse implications for water quality with respect to organic carbon, nutrients, and metals [2][3][4][5], and conversely growth can mitigate contaminant release and regulate surface and subsurface flows [6].…”

Research progress in ecosystem management strategies based on ecosystem services trade-offs

“…值得注意的是，在减少 ES 需求 (增加 ES 供给) 的同时也可能会减少 ES 供给 (增加 ES 需求) ，如不透水表面 (建筑用地) 的增加可以提高供水服务，但难以弥补城市扩张 和人口增加带来的用水激增 [52] ；一些地区实行封山育林、控制人口的措施可以减少当地 的用水需求，但林地、草地面积的增加也会抑制地表径流的增加从而减少供水服务 [53] ， 因此，需将提高供给措施与减少需求措施结合使用。 1.3 ES 供给-供给权衡管理策略 1.3.1 理论基础 在提高某一种 ES 的供给水平时，会有意或无意间造成另一种服务供给水平降低 [54] ， 这是因为存在 ES 供给-供给权衡 (简称"ES 供给间权衡") 。ES 供给间权衡不仅会降低 ES 总供给量，还会降低 ES 供给效率，从而影响生态系统管理的效果。因此，ES 供给间 权衡最理想的管理状态是实现高水平的 ES 供给或低水平的权衡程度 [55] 。 ES 供给间权衡管理策略分为两类，一是分区管理策略，二是驱动力调控策略。分区 管理策略的理论基础是 ES 供给间权衡的空间异质性，由于自然环境条件和社会经济条件 存在巨大的空间差异，使得 ES 供给间权衡方向及其强度产生了空间异质性 [56] ；驱动力调 控策略的理论基础是 ES 供给间权衡的驱动机制。 1.3.2 分区管理策略 了解 ES 供给间权衡的空间差异对于生态系统管理至关重要，若对具有多种 ES 关系 的区域进行同质化管理，则并不能达到最理想的管理状态，因此需对研究区域进行分 区，利用不同区域内不同对 ES 供给间权衡的特点，因地制宜提出针对性管理策略 [57] 。 有研究者根据 ES 供给间权衡方向进行了分区，如 Qian 等 [58] 根据祁连山地区保水服务 与畜牧生产服务间关系提出了区域差异化管理策略，在两者为负协同关系的区域实行禁 牧措施，在两者为权衡关系区域实行轮牧措施，在两者为正协同关系区域实行保持放牧 措施；Mashizi 等 [59] 在 Bagadm 盆地内发现在高海拔上 ES 簇关系为正协同，在中海拔上 ES 簇关系为权衡，在低海拔上 ES 簇关系为负协同，并对高、中、低海拔区域提出了三种不 同的发展策略。还有研究者按照 ES 供给间权衡强度进行了分区，如王世豪等 [60] [14] 提出的两种驱动机制，一是公共驱动力驱动两 ES 供给水 平，二是一种 ES 的供给水平会影响另一种 ES 的驱动水平。Xu 等 [62] 和 Zhang 等 [63] 在此基础 [50] ，探析驱动力与权衡间的定性关系，并提出了一些 列管理措施。如 Biel 等 [64] 研究表明，海岸地貌既能促进海岸防护，又能帮助千鸟繁殖， 即海岸地貌是两 ES 间协同关系的公共驱动力，因此可通过种植滩草实现两者的双赢； Yang 等 [65] 研究表明快速城镇化背景下，土地利用对产水服务与固碳服务间权衡的影响逐 渐减小，降雨等不确定因子对权衡的影响逐渐增大，因此需要通过城市绿地化或海绵城 市建设等方式缓解降雨对 ES 的负面影响；Qiu 等 [66] 对陕西省三个气候带内土壤保持服务 与食物供应服务的研究表明，施肥管理、人口密度等社会因子是供给间权衡的主要驱动 力，而温度、降雨、地形等自然因子对权衡的影响有限；Zeng 等 [67] 对水质净化与固碳服 务的权衡分析表明，在长三角地区东西部，建筑用地面积与年均气温变化对两者的供给 间权衡强度有负向影响。 上述研究普遍考虑了供给间权衡的空间异质性，提出的管理措施也大多为定性表 达，但囿于供给间权衡的空间差异，其对供给权衡驱动力的分析大多基于地理加权回 归。还有研究者通过全局性回归等方法，建立了供给间权衡与驱动力的响应函数，探讨 了驱动力对权衡强度、权衡方向、权衡阈值等的影响，此类研究能帮助决策者提出更精 细的土地利用配置与政策建议。例如，Feng 等 [68] 在安塞流域的研究表明，草地会减弱碳 固存与产水服务间的权衡而林地会增加他们的权衡，因此在权衡强度较强的区域应限制 林地面积而增加草地面积；Feng 等 [69] 确定了土地利用类型比例对 ES 供给间权衡的影响阈 值，提出了精确的土地利用转移比例；Xu 等 [70] 在关联 [71,72] 尺度下供给间权衡的方向 [73] 、强度 [74] 与阈值 [75] 等均会发生改变；不同时空尺度下利益相关 者偏好冲突也不同，区域尺度的利益相关者可能更关注食物供应、美学服务等 ES，而全 球尺度的利益相关者可能更关注气候调节、水源涵养等 ES [76] ；同时，不同时空尺度 ES 供 需比格局也不相同 [77,78] [79] ；NPP、食物供 应、产水服务和土壤保持服务四种 ES 的权衡关系用林地、农田、草地三种土地利用面积...…”