Joint preservation of ecological systems and farm livelihoods in the Galapagos Islands through effective land use

Abstract

Agriculture is a major driver of global biodiversity loss and environmental degradation, yet it is indispensable for ensuring food security. In Galapagos Islands, however, this apparent trade-off could become a positive interaction: agriculture supports food production and plays a crucial role in controlling invasive plant species that threaten native ecosystems. More productive agricultural systems could further reduce the risk of introducing invasive species, since food imports are one of the main ways in which species enter the islands. At the same time, the archipelago is facing growing food security risks due to its heavy reliance on imports and an ongoing nutritional transition towards ultra-processed foods. Local agriculture is increasingly discouraged due to high production costs, partly because of the costly investment required for plant invasion control, and consumer preferences for imported products. These dynamics create a coupled socio-ecological challenge, whereby declining local agriculture, the expansion of invasive plants and dietary shifts reinforce one another. This dissertation explores how agricultural development can help reconcile food security, rural livelihoods, and ecosystem conservation in the rural highlands of Galapagos. It adopts an interdisciplinary approach that integrates biophysical and socio-economic data through three complementary studies. First, it quantifies the extent, distribution, and recent expansion of invasive plant cover using remote sensing and machine learning techniques. Second, it identifies the socio-economic drivers of invasive plant cover in the rural areas, highlighting the role of land use decisions and income sources. Third, it develops an integrated land-use optimization model to assess how different production and dietary scenarios could affect food security, farm income, invasive plant control, and the preservation of native vegetation in the future. The results show that invasive plant species continue to expand across rural and adjacent protected areas, posing a persistent threat to biodiversity and increasing management costs for farmers. At the same time, evidence suggests emerging transitions from homogeneous invaded systems toward more diverse novel ecosystems. Socio-economic analysis shows that farms more dependent on agriculture tend to maintain lower extents of certain invasive species cover such as Psidium guajava, while tourism-oriented farms exhibit higher extents. Biophysical factors play a key role in shaping distributions of other invasive pants like Cedrela odorata. The modelling results further indicate that more balanced diets, particularly those rich in fruits and vegetables, could generate environmental benefits by increasing demand for local production, converting unmanaged invaded land into cropland, and promoting more diversified agricultural landscapes. Overall, this thesis demonstrates that, under appropriate conditions, agriculture in Galapagos can generate synergies between food production and ecosystem conservation under appropriate conditions. Strengthening local food systems, supporting agroecological practices, and aligning more balanced consumption patterns with local production have the potential to reduce invasive plant cover while enhancing food security and supporting rural livelihoods. These findings contribute to broader debates on sustainable development in island systems and other constrained socio-ecological contexts where local food production, rural livelihoods and biodiversity conservation are tightly interconnected.