A Landscape Index to link landscape pattern with nutrient loss at watershed scale
Abstract
How to assess the effects of landscape pattern on ecological processes is a central yet challenging research theme in landscape ecology. Although many landscape metrics were established in the past decades to describe the landscape pattern, few of them can be used to denote the ecological processes. In this paper, a new landscape index, i.e., location-weighted landscape index (LWLI) was introduced by examining the role of each landscape type in ecological processes, for example nutrient loss, soil erosion. In principle, each land use type plays either as a source or a sink in the development of ecological process, such as nutrient loss and soil erosion at a watershed, otherwise it may act as a pathway in the process. The effects of landscape pattern on nutrient loss (or soil erosion) in a watershed could be determined based on its spatial arrangement of source and sink landscapes. If the contribution of source landscapes is higher than that of sink landscapes, this watershed may produce more nutrient loss (or soil erosion) compared with a watershed having more sink landscapes. In this paper, the index was developed by using the Lorenz curve theory, and then a case study was conducted in two watersheds in the agricultural areas of northeastern China. By comparing the value of LWLI index and the on-site measurements of surface water quality, it was found that nutrient loss tends to be higher as LWLI value is getting bigger, and vice versa. In addition, this index was applied to a large basin. We found the landscape index LWLI can be used to evaluate the potential risk of nutrient loss or soil erosion in a watershed based on landscape pattern analysis. This index can better reflect the effects of landscape pattern on the process with material flow, and special cares should be given when applying this index to the other process such as the energy or information flow.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H42A..05C
- Keywords:
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- 1632 Land cover change;
- GLOBAL CHANGEDE: 1834 Human impacts;
- HYDROLOGYDE: 1847 Modeling;
- HYDROLOGYDE: 1879 Watershed;
- HYDROLOGY