Hot spots of wetland vegetation reduction in relation to human accessibility: differentiating human impacts on natural ecosystems at multiple scales
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Human activities have profoundly influenced natural ecosystems, especially wetlands. This study attempted to differentiate the impact of human activities on reductions in wetland vegetation in the Lixiahe wetlands, China, at multiple spatial scales. The reduction in wetland vegetation from 1988 to 2006 was quantified using Landsat data, and moving window analysis was used to detect hot spots of vegetation reduction in the wetlands at window sizes of 150, 1,000 and 2,500 m. Logistic regression was used to examine the influence on occurrence of the hot spots of landscape variables representing accessibility to human settlements and roads. Over the study period, wetland vegetation declined by 69%, which was largely attributable to aquaculture development. The hot spots of wetland vegetation reduction exhibited increasing patch size, but decreasing patch number with increasing window size. The occurrence probability of the hot spots rose significantly with increasing proximity to rural settlements and secondary roads, with only a minor response to the presence of towns. With increasing window size, however, the density of secondary roads and rural settlements were less influential, whereas the presence of major roads had more influence on hot spot occurrence. These trends are reasonable in that wetland use activities in the study area are directly associated with the settlements and roads in the rural areas at local scales, but are also indirectly associated with the major transportation network from a regional perspective. Overall, these results suggested that different human activities, as distinguished by their sources on the landscape, could have different environmental consequences at different scales for scale-dependent features.
KeywordsHot spots Human accessibility Land cover change Landsat Remote sensing Wetlands
We would like to thank Dr. Jianguo Wu for enlightening discussion on this manuscript and three anonymous reviewers for their valuable comments. This research was supported by the Special Forestry Project of Public Interests (200904001), the Key Project of Control and Treatment of Water Pollution of China (2008ZX07526-002-03) and the National Natural Science Foundation of China (30870433 and 40801068).
- Bossuyt F, Meegaskumbura M, Beenaerts N, Gower DJ, Pethiyagoda R, Roelants K, Mannaert A, Wilkinson M, Bahir MM, Manamendra-Arachchi K, Ng PKL, Schneider CJ, Oommen OV, Milinkovitch MC (2004) Local endemism within the Western Ghats-Sri Lanka biodiversity hotspot. Science 306(5695):479–481CrossRefGoogle Scholar
- Goudie A (2006) The human impact on the natural environment: past, present and future, 6th edn. Blackwell, CambridgeGoogle Scholar
- Jiangsu Forestry Bureau (2000) Report of Wetland inventory of Jiangsu province. Jiangsu Forestry BureauGoogle Scholar
- Jiangsu Statistical Bureau (2007) Statistical year book of Jiangsu. China Statistics Press, BeijingGoogle Scholar
- Kwan MP, Weber J (2003) Individual accessibility revisited: implications for geographical analysis in the twenty-first century. Geogr Anal 35(4):341–353Google Scholar
- Mitsch WJ (2005) Applying science to conservation and restoration of the world’s wetlands. Water Sci Technol 51(8):13–26Google Scholar
- Penteriani V, Gallardo M, Roche P, Cazassus H (2001) Effects of landscape spatial structure and composition on the settlement of the Eagle Owl Bubo bubo in a Mediterranean habitat. Ardea 89(2):331–340Google Scholar
- Shi Q, Liu MS, Song J, Xu C, Chen H (2008) Dynamic analysis on settlement percentage coverage in urbanization. Chin J Ecol 27(11):1979–1984Google Scholar
- Xu C, Sheng S, Zhou W, Cui LJ, Liu MS (2011) Characterizing wetland change at landscape scale in Jiangsu Province, China. Environ Monit Assess. doi: 10.1007/s10661-010-1735-6