Quantifying the spatiotemporal patterns of urbanization along urban-rural gradient with a roadscape transect approach: a case study in Shanghai, China

Abstract

Quantifying the landscape pattern change can effectively demonstrate the ecological progresses and the consequences of urbanization. Based on remotely sensed land cover data in 1994, 2000, 2006 and a gradient analysis with landscape metrics at landscape- and class- level, we attempted to characterize the individual and entire landscape patterns of Shanghai metropolitan during the rapid urbanization. We highlighted that a roadscape transect approach that combined the buffer zone method and the transect-based approach was introduced to describe the urban-rural patterns of agricultural, residential, green, industrial, and public facilities land along the railway route. Our results of landscape metrics showed significant spatiotemporal patterns and gradient variations along the transect. The urban growth pattern in two time spans conform to the hypothesis for diffusion–coalescence processes, implying that the railway is adaptive as a gradient element to analyze the landscape patterns with urbanization. As the natural landscape was replaced by urban landscape gradually, the urban fringe expanded radically. The results also showed that the desakota region expanded its extent widely. Satellite towns witnessed the continual transformation from the predominantly rural landscape to peri-urban landscape. Furthermore, the gap between urban and rural areas remained large especially in public service. More reasonable urban plans and land use policies should push to make more of an effort to transition from the urban-rural separation to coordinated urban-rural development. This study is a meaningful trial in demonstrating a new form of urban–rural transects to study the landscape change of large cities from a strategic viewpoint. By combining gradient analysis with landscape metrics, we addressed the process of urbanization both spatially and temporally, and provided a more quantitative approach to urban studies.

Spatial variations of soil seed banks in Shanghai’s urban wasteland: A gradient analysis of urbanization effects

“…Our nding of dominant position of native species and no signi cant difference in the proportions of native versus exotic species along the urban-rural gradient challenges the common assumption that urbanization invariably leads to an increase in exotic species at the expense of natives (Figueroa et , where the proportion of native species in soil seed banks is higher than that of exotic species. A high proportion of native species in aboveground vegetation communities with no signi cantly different along the urban-rural gradient were found in Shanghai in previous studies (Tian et al, 2008;Zhang, 2017). It suggests that the native species in our study area may be more resilient to urbanization pressures or that exotic species have not yet established a strong foothold in the local seed bank.…”

“…Species were categorized as native or exotic according to "Plant Directory of Five Provinces and One City in East China" (Zhang & Lai, 1993) and the "Wild Higher Plants Atlas of Shanghai Urban Area" (Qin et al, 2016). Germinating species were classi ed by life forms as annual or perennial, with annuals further categorizing into winter and summer annual (Zhang, 2017)…”