A Model for Estimating the Vegetation Cover in the High-Altitude Wetlands of the Andes (HAWA)

Jorge Soto,Manuel Paneque,Celián Román-Figueroa

doi:10.3390/land8010020

Jorge Soto, Manuel Paneque + Show 1 more

Open Access

https://doi.org/10.3390/land8010020

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Abstract

The natural salt meadows of Tilopozo in the hyperarid, Atacama Desert of northern Chile, which are located at approximately 2800 m above sea level, are under pressure from industrial activity, and cultivation and grazing by local communities. In this research, the land surface covered by salt meadow vegetation was estimated from normalized difference vegetation indices (NDVI) derived from Landsat Thematic Mapper (TM), Enhanced Thematic Mapper (ETM+) and Operational Land Imager (OLI) data from 1985 to 2016. The vegetated area of the Tilopozo salt meadows decreased by 34 ha over the 32-year period studied. Multiple regression models of the area covered by vegetation and climate data and groundwater depths were derived on an annual basis, as well as for both the dry and wet seasons and had R2 values of 83.0%, 72.8% and 92.4% respectively between the vegetated areas modeled and those estimated from remotely sensed data. These models are potentially useful tools for studies into the conservation of the Tilopozo salt meadows, as they provide relevant information on the state of vegetation and enable changes in vegetation in response to fluctuations in climate parameters and groundwater depths to be predicted.

Highlights

The importance of wetlands is greater in places where water resources are scarce, e.g., the arid and semi-arid ecosystems of South America [1,2]
The differences observed in the changes in water table depths can be explained by the structure of the aquifer and the soils of the salt meadows, which were described as having different permeabilities, which facilitates or hinders the movement of water [42]
Vyacheslav et al [43] observed that the well and the piezometers upstream of the salt meadows of Tilopozo presented greater water table depths due to the cone of depression produced by the extraction of waters in the upper part of the MNT-aquifer

Summary

Introduction

The importance of wetlands is greater in places where water resources are scarce, e.g., the arid and semi-arid ecosystems of South America [1,2]. In the Altiplano regions of South America, there are wetlands at high altitudes, which are located at the maximum altitude for vegetation growth and at less than the zero isotherms [1]. In these locations, natural salt meadows can be found [1,3]. The salt meadows of Tilopozo are located to the south of the Salar de Atacama, Chile [7], and the presence of the ecosystem depends on the discharge of the flow from the Monturaqui-Negrillar-Tilopozo aquifer (MNT-aquifer), which has an extension of 60 km [8]. Since 1986, water has been extracted from the MNT-aquifer for industrial purposes (metallic and non-metallic mining), and this has an established monitoring plan through a water monitoring network for the conservation of this wetland [9]

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