- Develops a novel climatic archive
- Field work to explore unique tropical environments
- Multidisciplinary study Ecophysiological
In the northern Neotropics glacial melt water and unique yet vulnerable high-altitude alpine Andean grasslands and wetlands (known as páramo) are key sources of fresh water. Ultimately, they feed the largest watersheds on earth, the Orinoco and Amazon basin. Andean glaciers have been the subject of intensive study (Thompson et al., 2006) and the potential implications of climatic change and glacial melting for water supply have been assessed (Ruiz et al., 2008). In comparison wetlands have received scant attention, despite the fact that páramos provide critical ecosystem services and are the main source of surface water for a number of major cities (Celleri & Feyen, 2009, Iñiguez et al., 2015). These regions are densely populated; the páramo of Chingaza (Colombia) and its surrounding Andean landscape provide water for 10 million people, including 80% of clean drinking water for the 8 million people of Bogota. Similarly, 2.5 million inhabitants Quito, Ecuador, obtain 95% of their drinking water from páramo environments. Critical to this is the fact that páramo soils (often Histosols and Andosols) are rich in organic matter and have a very high water holding capacity (Hofstede 2002), which maintains this year-round water availability. Irrespective of climatic change, páramo is a highly endangered and fragile ecosystem. Conversion to agriculture and tillage has resulted in massive soil erosion and significant loss of water holding capacity in páramo soils (Buytaert et al., 2006; Dercon et al., 2007). The likely response of these systems, whether disturbed or pristine, to future climatic change is presently unclear, but the archaeological record provides clear reasons for concern as there is strong evidence that severe El Niño events affected the adaptive capacity of local societies, resulting in significant cultural change (Baied & Wheeler, 1993; Binford et al., 1997; Magilligan & Goldstein, 2001). Prolonged drought spells result in significant burning of páramo (Borrelli, 2015). Thus, climate change and increased agricultural practices pose a severe threat to páramo fresh water resources.
Stable isotopes are powerful tools to study eco-physiological responses of plants and ecosystems to climate and environmental change. Isotopic analysis of tree rings in particular has been a very successful method to achieve this, carbon isotopes are recording water use efficiency while oxygen and deuterium isotopes provide information on precipitation. However the high Andean wetlands are located above the treeline, this project, therefore will use novel vertical archives of the giant stem rosettes that are so characteristic for these environments as analogues of tree rings. We aim to investigate in particular the hydrological changes in páramo wetlands, as driven by climate and man, and will seek to understand the baseline sensitivity of these systems during the last century. A recent pilot study conducted at Leicester has resulted in a 30 year annually resolved record of water use efficiency. This approach will provide us with an unprecedented spatial and temporal in depth assessment of the water use efficiency and hydrological changes of the páramo ecosystem.
Field work will be conducted in the paramos of the Eastern Cordillera in Colombia, standing litter fragments will be collected from Espeletia plants. Historical climate data will be provided by IDEAM. Stable isotope analysis including carbon, oxygen and deuterium, of standing litter, soils and water will will be used to study the evolution of the hydroclimate and its impact on the ecoystem at high temporal and spatial resolution.
Training and Skills
CENTA students are required to complete 45 days training throughout their PhD including a 10 day placement. In the first year, students will be trained as a single cohort on environmental science, research methods and core skills. Throughout the PhD, training will progress from core skills sets to master classes specific to CENTA research themes.
The student will obtain training in isotope ratio monitoring mass spectrometry and various multivariate statistical analyses. In addition he or she will receive training on sample collection in the field, ecology, vegetation surveys, hydrological modelling, remote sensing.
Year 1: Literature review, stable isotope course, specific training for: A) sample preparation for isotope analysis. Planning and conducting field work. Collect climate data.
Year 2: Preparing and analysing leaf samples, meteoric and ground water samples.
Year 3: Statistical analysis. Testing of results with models for isotopic enrichment in (leaf) water and intrinsic water use efficiency.
Partners and collaboration (including CASE)
Boom is a stable isotope geochemists and Berrio is a palaeoecologist. The project will build on existing collaboration with the palaeoecology research group from the University of the Andes and the National University in Bogota, Colombia (Associate professor Dr. Catalina Gonzalez Arango), together with IDEAM (Colombian institute for hydrology, meteorology and environmental studies).