Seasonal water storage and release dynamics of bofedal wetlands in the Central Andes

Abstract

Tropical high‐Andean wetlands, locally known as ‘bofedales’, are key ecosystems sustaining biodiversity, carbon sequestration, water provision and livestock farming. Bofedales' contribution to dry season baseflows and sustaining water quality is crucial for downstream water security. The sensitivity of bofedales to climatic and anthropogenic disturbances is therefore of growing concern for watershed management. This study aims to understand seasonal water storage and release characteristics of bofedales by combining remote sensing analysis and ground‐based monitoring for the wet and dry seasons of late 2019 to early 2021, using the glacierised Vilcanota‐Urubamba basin (Southern Peru) as a case study. A network of five ultrasound loggers was installed to obtain discharge and water table data from bofedal sites across two headwater catchments. The seasonal extent of bofedales was mapped by applying a supervised machine learning model using Random Forest on imagery from Sentinel‐2 and NASADEM. We identified high seasonal variability in bofedal area with a total of 3.5% and 10.6% of each catchment area, respectively, at the end of the dry season (2020), which increased to 15.1% and 16.9%, respectively, at the end of the following wet season (2021). The hydrological observations and bofedal maps were combined into a hydrological conceptual model to estimate the storage and release characteristics of the bofedales, and their contribution to runoff at the catchment scale. Estimated lag times between 1 and 32 days indicate a prolonged bofedal flow contribution throughout the dry season (about 74% of total flow). Thus, our results suggest that bofedales provide substantial contribution to dry season baseflow, water flow regulation and storage. These findings highlight the importance of including bofedales in local water management strategies and adaptation interventions including nature‐based solutions that seek to support long‐term water security in seasonally dry and rapidly changing Andean catchments.

Spatially distributed tracer‐aided modelling to explore DOC dynamics, hot spots and hot moments in a tropical mountain catchment

“…Due to the significant amount of water flowing from the slopes (78% of the catchment area) or Andosols to recharge the valleys or Histosols, the valleys themselves become large water conduits. These conduits are often saturated and rapidly transport a substantial amount of water within the them and to the streams (Mosquera et al, 2015; Ross et al, 2023), and DOC towards the main stream during wet periods. These flat areas at the bottom of the slopes become ‘temporary sinks’ for DOC that can be activated depending on the current or antecedent hydro‐meteorological conditions of the catchment (DOC production hot spots).…”

Mapping high-altitude peatlands to inform a landscape conservation strategy in the Andes of northern Peru

“…The combination of several covariates, as Minasny et al (2019) recommended, including optical, radar and topographical covariables, positively trained the random forest machine algorithm. A similar methodology was successfully used to map wetlands and peatlands in the Andes (Hribljan et al 2017, Chimner et al 2019, Ross et al 2023 and Indonesia (Rudiyanto et al 2018). The need for such methods is internationally relevant.…”

“…Andean wetlands in general, including peatlands, have only been recently studied and mapped (Otto et al 2011, Ochoa-Tocachi et al 2016, Otto & Gibbons 2017, Chimner et al 2019, Ross et al 2023, and they are clearly absent from the global wetland and peatland databases, such as PEATMAP and PEAT-ML (Xu et al 2018, Melton et al 2022, the CIFOR Global Wetlands Database (Chimner et al 2019) or the global peatland map of Leifeld and Menichetti (2018). Only the Global Peatland Map 2.0 (Global Peatlands Initiative 2022) included a few peatland areas in the Andes, but none were from the jalca ecoregion.…”

Environmental Filters Structure Cushion Bogs’ Floristic Composition along the Southern South American Latitudinal Gradient

“…Furthermore, 64% -65% of the variance remains unexplained in both models, suggesting the influence of unconsidered factors such as biological interactions, the sources and physicochemical characteristics of the waters associated with bogs, topography (slope), and anthropogenic impact variables, all of which have evidenced their impact on floristic composition [14,15,30,49].…”