Spatiotemporal Peatland Productivity and Climate Relationships Across the Western South American Altiplano

Abstract

The South American Altiplano is one of the largest semiarid high‐altitude plateaus in the world. Within the Altiplano, peatlands known as “bofedales” are important components of regional hydrology and provide key water resources and ecosystem services to Andean communities. Warming temperatures, changes in hydroclimate, and shifting atmospheric circulation patterns all affect peatland dynamics and hydrology. It is therefore urgent to better understand the relationships between climate variability and the spatiotemporal variations in peatland productivity across the Altiplano. Here, we explore climate influences on peatland vegetation using 31 years of Landsat data. We focus specifically on the bofedal network in the western Altiplano, the driest sector of the plateau, and use the satellite‐derived Normalized Difference Vegetation Index (NDVI) as an indicator of productivity. We develop temporally and spatially continuous NDVI products at multiple scales in order to evaluate relationships with climate variables over the past three decades. We demonstrate that cumulative precipitation and snow persistence over the prior 2 years are strongly associated with growing season productivity. A step change in peatland productivity between 2013–2015 drives an increasing trend in NDVI and is likely a response to consecutive years of anomalously high snow accumulation and rainfall. Early summer minimum temperatures emerge as a secondary influence on productivity. Understanding large‐scale productivity dynamics and characterizing the response of bofedales to climate variability over the last three decades provides a baseline to monitor the responses of Andean peatlands to climate change.

Hydroclimate and vegetation variability of high Andean ecosystems

“…The response of vegetation to temperature, also observed by other authors (Maggi et al, 2020) is probably associated with a thermic limit to plant growth described by global analyses of montane systems (Körner, 1999;Pauli & Halloy, 2019). Likewise, the increasing trend in SAVI in the last years, also observed in other high mountains (Gaitań et al, 2015;Chavez et al, 2019;Campbell et al, 2021;Anderson et al, 2021), could be a response to the increase in temperatures (in tune with global warming, Xu et al, 2019;Xu et al, 2020) recorded in both lower elevation meteorological stations. Other authors have suggested that increasing vegetation activity in montane systems is related with the occurrence of anomalous rain and snow episodes (Otto et al, 2011;Anderson et al, 2021).…”

“…We classified three types of environments that are dominated by different vegetation communities: peatlands, plains, and hillsides. Peatlands (410 ha were classified as peatlands) are known to be temporarily flooded environments with highly green productive vegetation communities (Izquierdo et al, 2015b;Meneses et al, 2020;Anderson et al, 2021), distinguishable from the semiarid matrix. Plains (1099 ha) and hillsides (3736 ha) are dominated by different vegetation communities and their soils have different water retention capacities.…”

“…At the same time, Vuille et al (2018) showed faster rates of warming in higher elevation than lowlands, which together with the increasing impact of anthropogenic pressure (Izquierdo et al, 2018), may threaten the vegetation adapted to these Andean ecosystems. Due to the importance of the Andes in terms of biodiversity, water supply to lowland cities and agriculture (Olson et al, 2001;Anderson et al, 2021), and particularly, the dry Central Andes includes lithium triangle, so the anthropic pressure is likely to increase in the next few years (Izquierdo et al, 2015a) there is an urgent need to understand their dynamics and the main drivers of changes. However, the scarcity of climate records in these environments fosters the exploration of alternative hydroclimate indicators to gather long-term information.…”

Glacier influence on bird assemblages in habitat islands of the high Bolivian Andes

“…water provision by the glacier) may influence species composition through resource constraints and habitat complexity (McCain, 2009;Worm & Tittensor, 2018;Zhang et al, 2020). NDVI has been long used as proxy of productivity of Andean wetlands as it is sensitive to the greenness of photosynthetically active biomass (Anderson et al, 2021;Chávez et al, 2019;Moreau et al, 2003). However, these satellite image analyses do not allow quantifying wetland value as direct feeding habitat for waterbirds.…”

Floristic types of high‐Andean wetlands from northwest Argentina and their remote‐sensed characterization at a regional scale

“…Remote sensing is a field of applied science that offers interesting benefits to the study and observation of the environment at different temporal and spatial scales, especially for remote places (Johnson, 1990; Vihervaara et al, 2015). These tools are applied to mapping high‐Andean wetlands (Araya‐Lopez et al, 2018; Izquierdo et al, 2015, 2016) and to characterize some specific ecological processes such as hydrological fluctuations (Casagranda et al, 2019; de la Fuente et al, 2021; Garcia & Otto, 2015; Otto et al, 2011), productivity dynamics (Anderson et al, 2021; Casagranda et al, 2019; Chávez et al, 2019) or temporal above‐ground plant biomass dynamics (Moreau et al, 2003). This applicability could be useful to characterize the biogeographic variability of high‐Andean vegas (Izquierdo et al, 2020) allowing us to analyze and monitor them spectrally.…”