This dissertation examines sociocultural and biophysical reconfigurations in an Andean agricultural landscape. Decline in the diversity of crops grown by the worlds farmers has long been a scientific concern. Recently, climate change has been recognized as a new threat to agricultural sustainability, further heightening the need for diverse crops adapted to a broad range of environmental conditions. Still, there is inadequate scientific insight into the present extent of agrobiodiversity in farmers fields and the dynamics affecting its loss and persistence.The present research examines these issues through an in-depth and longitudinal case study in Cotacachi, located in the Northern Ecuadorian highlands. It sets out to document the areas crop and varietal diversity, and spatial and temporal change in the composition of crops in farmers fields. In particular, it examines whether and how these field reconfigurations relate to shifts in cultural and climatic patterns. The study builds on 16 months of fieldwork between 2003 and 2010, employing participatory observation, interviews, surveys, focus group discussions, workshops and mapping. The results show that Cotacachis fields are populated with rich agrobiodiversity, encompassing 103 crop species and a total of 367 varieties within 20 of these. This richness, however, is not evenly distributed most crops and varieties are present in low frequencies while a few are widespread. The low frequencies partly result from a reduction in the extent of many crops and varieties during the past century, yet this trend has been partly reversed in the course of the last decade. This decline and expansion of diversity bear close linkages to sociocultural trends affecting the value and priority attributed local food and agriculture. Recent climate change challenges farming in multiple ways, generally resulting in lower harvests. On one hand, this process hampers seed saving, but on the other, farmers draw on the local agrobiodiversity as they reconfigure the crop composition of their fields in response to warmer temperatures and changing precipitation regimes. The findings point to the potential of cultural revitalization to spark agricultural diversification, and highlight the importance of supporting the maintenance of locally rooted crop diversity to enhance farmers resilience to climate change.