Nonlinear Changes in Land Cover and Sediment Runoff in a New Zealand Catchment Dominated by Plantation Forestry and Livestock Grazing
Nonlinear Changes in Land Cover and Sediment Runoff in a New Zealand Catchment Dominated by Plantation Forestry and Livestock Grazing
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DOI：
10.3390/w8100436
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发表时间：
2016-10-01
期刊：
影响因子：
3.4
通讯作者：
de Beurs, Kirsten M.
中科院分区：
文献类型：
--
作者：
Kamarinas, Ioannis;Julian, Jason P.;de Beurs, Kirsten M.
在集约化管理的景观中，土地覆盖可能会频繁变化，影响不同时空尺度的水质。为了评估这些变化的程度和趋势以及潜在的跨尺度相互作用，需要多分辨率数据集。在这项研究中，对从日到年时间尺度的数据集进行了土地扰动（即植被去除造成的土壤暴露）和水质的空间和时间分析。将土地扰动的时间序列分析与 2000-2013 年新西兰北岛 Hoteo 河流域的总悬浮固体 (TSS)、浊度和视觉清晰度等水质变量进行比较。在森林采伐和恢复阶段，外来森林是主要干扰，其面积达到草地干扰面积的五倍；恢复后，草原占据主导地位，其面积达到森林干扰面积的16倍。现场采样（2000-2013）和 TSS 事件分析（2012-2014）的 TSS 时间序列显示出明显的非线性模式，表明重大事件发生后，景观中储存的沉积物会耗尽，随后会出现一段沉积物堆积期，直到下一次重大事件发生。时间序列分析还显示了相连的土地扰动趋势与视觉水体清晰度之间的联系，其中相连的扰动有可能成为水质指标。未来的研究应该在更精细的时空尺度上、更长的时间内进行，以便确定局部土地扰动对下游水质的影响。
Land cover can change frequently on intensively managed landscapes, affecting water quality across different spatiotemporal scales. Multi-resolution datasets are necessary in order to assess the extent and trends of these changes, as well as potential cross-scale interactions. In this study, both spatial and temporal analyses of land disturbance (i.e., soil exposure from vegetation removal) and water quality were performed on datasets ranging from daily to yearly time scales. Time-series analyses of land disturbance were compared against the water quality variables of total suspended solids (TSS), turbidity, and visual clarity for the Hoteo River catchment on the North Island of New Zealand for the 2000-2013 period. During forest harvest and recovery phases, exotic forests were the dominant disturbance, up to five times the area of grassland disturbance; while after recovery, grasslands assumed the dominant role, for up to 16 times the area of forest disturbance. Time-series of TSS from field sampling (2000-2013) and TSS-event analyses (2012-2014) displayed distinct nonlinear patterns, suggesting that after major events, sediment that is stored in the landscape is exhausted and a period of sediment build-up follows until the next major event. Time-series analyses also showed a connection between trends in connected land disturbance and visual water clarity, with connected disturbance having the potential to be a water quality indicator. Future research should be conducted at even finer spatiotemporal scales over longer periods in order to identify effects of localized land disturbances on downstream water quality.