Urban Land Cover Change in Ecologically Fragile Environments: The Case of the Galapagos Islands

Abstract

Abstract:The Galapagos Islands are a unique sanctuary for wildlife and have gone through a fluctuating process of urbanization in the three main inhabited islands. Despite being colonized since the 1800s, it is during the last 25 years that a dramatic increase in population has been observed. Analyzing impervious surface change over this period in an ecologically fragile environment is a challenging task, thus two methods that have been widely employed in studying urban environments were compared in this study: sub-pixel using spectral mixture analyses (SMA) and object-based classification. The SMA linear model, applied over moderate spatial resolution imagery, does not produce accurate results for urban composition mapping showing significant spectral confusion between classes. Instead, the object-based classification using spectral indices proved to be more effective for detecting impervious surfaces over heterogeneous urban environments in inhabited islands. The accuracy assessment showed a correlation between estimated and true impervious surface abundance fraction higher than first expected (R 2 = 67.7%) for the object-based classification, considering the limitations of pixel size (Landsat imagery) in small heterogeneous urban landscapes. Hence, this methodology was applied to all three urban centers for further analysis. Through this assessment, the average annual growth rate in urban areas was calculated as 3.3% from 1992 to 2017. The foreseen applications and local implications for land planning and management are especially important for the Galapagos Islands. There is a need for planning systems and processes that involve all stakeholders, in order to support pre-existing conservation initiatives and sustainable development policies.

Governance Mechanisms and Barriers for Achieving Water Quality Improvements in Galapagos

“…The Galapagos Islands have experienced massive population growth and development in recent decades [18,19]. The local population increased 9.5% in the Galapagos islands between 2010 and 2015 [20] and the number of tourists visiting the islands increased 5% on average between 2007 and 2018 [21].…”

“…The local population increased 9.5% in the Galapagos islands between 2010 and 2015 [20] and the number of tourists visiting the islands increased 5% on average between 2007 and 2018 [21]. This growth has raised the local population's standard of living while simultaneously contributing to the deterioration of the fragile ecosystem [18].…”

Land Cover Classification of Complex Agroecosystems in the Non-Protected Highlands of the Galapagos Islands

“…However, this metric assumes that grid contents are homogenous. Given that we are dealing with high-resolution data and land cover classes that are often not discrete, we also assessed the accuracy of our maps by calculating the root mean square error (RMSE) and a correlation coefficient (R 2 ) like land cover classification studies that use high-resolution images [73][74][75][76].…”

“…To characterize the effectiveness of our classification for estimating land cover fractions, we calculated the percentages of the polygons that were occupied by the different classes, and obtained a root mean square error (RMSE) and a correlation coefficient (R 2 ) for each island and for each class c using Equations (2) and (3) [73][74][75][76], respectively:…”

A collaboratively derived environmental research agenda for Galápagos

“…This has led to the increase of impervious surface, with an average annual growth of urban areas of 3.3% between 1992 and 2017 (Benítez et al 2018). Although there has been some improvement in governance, failure to enforce regulations has led to over-development of urban seafronts and encroachment of infrastructure into natural ecosystems, while some building lots have been left abandoned in urban centres.…”