Monitoring the Change in Urban Vegetation in 13 Chilean Cities Located in a Rainfall Gradient. What is the Contribution of the Widespread Creation of New Urban Parks?

World Multidisciplinary Civil Engineering-Architecture-Urban Planning Symposium - WMCAUS

土木建筑工程

De La Barrera, Francisco^1 ; Henríquez, Cristian^1

Institute of Geography, Center for Urban Sustainable Development, Vicuña Mackenna, Macul

4860, Chile^1

关键词: Ecosystem services;    High spatial resolution;    Interannual variability;    Latitudinal gradients;    Monitoring programs;    Peri-urban areas;    Residential areas;    Urban sustainability;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/245/7/072023/pdf
DOI  :  10.1088/1757-899X/245/7/072023

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

The well-being of people living in cities is strongly dependent on the existence of urban vegetation because of the ecosystem services or benefits it provides. This is why governments develop plans to create green spaces, plant trees, promote the maintenance of vegetation in private spaces and also monitor their status over time. In Latin America, and particularly in Chile, the increase of urban vegetation has been stimulated through different initiatives and regulations. However, development of monitoring programs at the national level is scarce, so it is yet unknown if these initiatives and regulations have had positive effects. In this article, we monitor the change in urban vegetation in 13 Chilean cities located in a latitudinal gradient of practically zero to almost 1800 mm of annual rainfall. We calculated the trends in NDVI (2000-2016) as an indicator of change in urban greenery using data from the MODIS Subsets platform. Likewise, to assess whether the initiatives have had an effect we quantified the number of urban parks existing at the beginning of the period and how many were created during the study period. For this, we analysed official databases and high spatial resolution satellite images. Armed with said data, we assessed whether these new parks had impacted the tendency toward change in urban greenery. The results indicate that, in general, Chilean cities vary greatly inter-annually in urban greenery and have lost urban vegetation in the last 16 years, with significant losses in four of those cities. Two cities located in desert ecosystems represent an exception and showed positive trends in their urban vegetation. The rainfall in cities has an impact on the amount of vegetation, but not on their tendency to change, i.e. there are cities with loss of vegetation at all levels of precipitation. The creation of parks has not been able to reverse negative trends, which indicates the prevalence of other drivers of change that are not sufficiently compensated by initiatives and regulations that seek to increase urban vegetation. Today, planning and management of urban vegetation is a challenge for urban sustainability and must be addressed systematically, integrally and implemented via urban regulations. It is imperative to focus on cities in extenso, taking into consideration residential areas, private spaces, peri-urban areas, etc. Likewise, climate in each city, inter-annual variability and future changes must also be considered when designing green areas to make them resilient, prevent increases in maintenance costs and provide benefits for the inhabitants in perpetuity.