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It is largely unknown how South America's Andean forests affect the global carbon cycle, and thus regulate climate change. Here, we measure aboveground carbon dynamics over the past two decades in 119 monitoring plots spanning a range of >3000 m elevation across the subtropical and tropical Andes. Our results show that Andean forests act as strong sinks for aboveground carbon (0.67 ± 0.08 Mg C ha−1 y−1) and have a high potential to serve as future carbon refuges. Aboveground carbon dynamics of Andean forests are driven by abiotic and biotic factors, such as climate and size-dependent mortality of trees. The increasing aboveground carbon stocks offset the estimated C emissions due to deforestation between 2003 and 2014, resulting in a net total uptake of 0.027 Pg C y−1. Reducing deforestation will increase Andean aboveground carbon stocks, facilitate upward species migrations, and allow for recovery of biomass losses due to climate change. Here, the authors investigate the aboveground carbon sink efficiency of Andean forests. The study shows the high potential of these forests to serve as future carbon refuges, and urges to reduce deforestation and increase restoration. [ABSTRACT FROM AUTHOR]

The relationship between environment and organisms has been a central focus of community ecology. Different approaches have been made for analyzing different aspects of this interaction, but more integral studies are missing to understand the implications of the environment for the whole biodiversity at regional scales. In this work, we assess the structure of three biological groups (aquatic macroinvertebrates, birds, and plants) with different ecological characteristics in peatlands from the Argentinean Puna. High Andean peatlands are "oasis" of highly productive wetlands within a matrix of arid highland desert, and they present particular eco-geographic attributes. We found that the eco-geographic characterization of 47 sampled peatlands segregated into two main dimensions of variation: one driven by the elevation and related climatic gradient and the other by landscape features and productivity. The three biological groups analyzed differ in terms of the association between composition and the type of environment. While compositional differences in birds and plants are better explained by the first PCA axis than the second one, the opposite is true for aquatic macroinvertebrates. To enhance the biological interpretation of differences between groups of sites (dichotomization guided by signs of PCA axes scores), we obtained their list of indicator taxa. These differences should be considered to understand the implications of the environment for the whole biodiversity at regional scales. This study highlights the relevance of integrating different organisms when considering community patterns associated with eco-geographic gradients, and related management and conservation issues. [ABSTRACT FROM AUTHOR]

Global warming is forcing many species to shift their distributions upward, causing consequent changes in the compositions of species that occur at specific locations. This prediction remains largely untested for tropical trees. Here we show, using a database of nearly 200 Andean forest plot inventories spread across more than 33.5° latitude (from 26.8° S to 7.1° N) and 3,000-m elevation (from 360 to 3,360 m above sea level), that tropical and subtropical tree communities are experiencing directional shifts in composition towards having greater relative abundances of species from lower, warmer elevations. Although this phenomenon of 'thermophilization' is widespread throughout the Andes, the rates of compositional change are not uniform across elevations. The observed heterogeneity in thermophilization rates is probably because of different warming rates and/or the presence of specialized tree communities at ecotones (that is, at the transitions between distinct habitats, such as at the timberline or at the base of the cloud forest). Understanding the factors that determine the directions and rates of compositional changes will enable us to better predict, and potentially mitigate, the effects of climate change on tropical forests. With global warming, Andean forests are changing to include more trees of low-elevation, heat-loving species but rates of compositional change are not uniform across elevations and are insufficient to keep species in equilibrium with climate. [ABSTRACT FROM AUTHOR]

The numbering in the reference list was incorrect in the original article through numbers 29 to 65. The original article can be found online at https://doi.org/10.1038/s41467-021-22459-8. [Extracted from the article]

In Fig. 2 of this Article, the positive part of the y axis scale should read 0, 0.02, 0.04 instead of 0, 0.04, 0.02. This has been corrected online. [ABSTRACT FROM AUTHOR]