Country scale assessment of desertification: an analysis of vegetation dynamics and its climatic and anthropogenic drivers in Chile over the last 40 years

Abstract

Chile's diverse ecosystems and biodiversity value represent a challenge for sustainable development and the task of balancing economic growth, inclusion and environmental protection is critical. Chilean biodiversity faces threats from climate change and anthropogenic activities such as urbanisation, agricultural expansion, deforestation and industry-led afforestation. To develop effective policies for managing Chile's vegetation and ensuring the continued provision of ecosystem services, it is essential to understand the temporal and spatial dynamics of vegetation and their interactions with climate and human activities.
This study aimed to identify the primary drivers behind vegetation dynamics, that can explain different processes of land management and land degradation. It analysed 96.2% of the continental territory of Chile to assess vegetation dynamics, specifically browning and greening trends using AVHRR and MODIS 16-Day catalogues, over the last 40 years. Climate variables, such as changes, trends and patterns in precipitation and temperature were examined using ERA5 from ECWMF satellite data. Finally, for the analysis of anthropogenic activities, it was evaluated the land cover and land use change over the last 40 years, using Landsat TM and OLI. All analysis were conducted using a time frame from 1981 to 2022, with each variable used being assess using trends and time series analysis for the determination of significant trends over time. A pixel size of 5km x 5km was used to facilitate the categorisation of scenarios, favouring the assessment and correlation analysis for each variable used.
Our findings indicated that approximately 4.1% (~30,850 km²) of Chilean territory has experienced browning over the past 40 years, distributed across various regions and vegetation types, suggesting ongoing land degradation processes. Contrarywise, about 7% (~59,600 km²) of the territory shows a greening effect, predominantly in temperate climates. A land use/land cover analysis was made, and this effect was calculated and validated though LULC change analysis, where 6,700 km2 of area was found where precipitation is decreasing, temperature is increasing, but a LULC into Forest was found in the las four decades, indicating a forestation process.
Therefore, this study identified 475 km² of land meeting desertification criteria in Chile, which consist of persistent browning, declining precipitation, rising temperature, and land degradation through human activity, which in this case consisted in land cover change from Forest and agriculture into barren areas. Conclusively, highlighting the presence of desertification risk in Chile, a country that remains underexplored in the topic of desertification, and the vegetation dynamics with climate and anthropogenic factors that lead into this phenomena.

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Identifiers

ORCID for Daniela Ninoska Rivera Marin: orcid.org/0000-0001-9541-043X

ORCID for Jadu Dash: orcid.org/0000-0002-5444-2109

ORCID for Booker Ogutu: orcid.org/0000-0002-1804-6205

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