Location-weighted landscape contrast index: a scale independent approach for landscape pattern evaluation based on “Source-Sink” ecological processes
Location-weighted landscape contrast index: a scale independent approach for landscape pattern evaluation based on “Source-Sink” ecological processes
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作者：
Chen Li
了解景观格局与生态过程之间的关系是景观生态学深入研究的关键。然而，由于景观格局和过程是尺度依赖性的，沿着生态过程监测数据的获取困难，很难量化这种关系。本文在非点源污染的框架下，分析了不同景观类型及其空间格局的作用和功能。在此基础上，提出了一种新的景观度量指标，即位置加权景观对比度指数（LCI）。在洛伦兹理论的框架下，该指数可以用来评价景观格局对生态过程的影响与距离、相对海拔和坡度有关。它可以通过基于点的生态测量来量化景观空间格局。它有四大特点。首先，该指数是规模独立的。其次，该指数特别适用于降雨和土壤方面均质的景观。第三，该指数可以用来表征景观空间格局对特定监测点的相对贡献。指数越大，贡献越大。最后，应该指出的是，LCI的绝对值不能用来预测非点源污染物或土壤侵蚀量。通过对不同流域LCI指数的比较，可以利用LCI值来评价流域养分（包括水土）流失的潜在风险。
Understanding the relationship between landscape pattern and ecological processes is critical for any in depth research in landscape ecology. However, it is difficult to quantify this relationship given the fact that landscape pattern and processes are scale dependent, along with the difficulty in acquiring ecological processes monitoring data. In this paper, we analyze the roles and functions of different landscape types and their spatial patterns under a framework of non point source pollution. We further propose a new landscape metric index, namely, location weighted landscape contrast index (LCI). Under a framework of the Lorenz Theory, this index can be used to evaluate the effect of landscape pattern upon ecological processes as related to distance, relative elevation, and slope degree. It can be used to quantify landscape spatial pattern by using point based ecological measurements. It has four major characteristics. First, the index is scale independent. Second, the index is particularly suitable for homogeneous landscape in terms of rainfall and soil. Third, this index can be used to characterize the relative contribution of landscape spatial pattern to a specific monitoring point. The bigger the index is, the larger the contribution will be. Last, it should be noted that the absolute value of LCI cannot be used to predict the amount of non point source pollutants or soil erosion. However, the value of LCI can be used to evaluate the potential risk of nutrient (including water and soil) loss by comparing the LCI indexes for different catchments.