Location-weighted landscape contrast index: a scale independent approach for landscape pattern evaluation based on “Source-Sink” ecological processes

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.