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    Functional rarity and evenness are key facets of biodiversity to boost multifunctionality
    (National Academy of Sciences, 2021-02-16)
    The functional traits of organisms within multispecies assemblages regulate biodiversity effects on ecosystem functioning. Yet how traits should assemble to boost multiple ecosystem functions simultaneously (multifunctionality) remains poorly explored. In a multibiome litter experiment covering most of the global variation in leaf trait spectra, we showed that three dimensions of functional diversity (dispersion, rarity, and evenness) explained up to 66% of variations in multifunctionality, although the dominant species and their traits remained an important predictor. While high dispersion impeded multifunctionality, increasing the evenness among functionally dissimilar species was a key dimension to promote higher multifunctionality and to reduce the abundance of plant pathogens. Because too-dissimilar species could have negative effects on ecosystems, our results highlight the need for not only diverse but also functionally even assemblages to promote multifunctionality. The effect of functionally rare species strongly shifted from positive to negative depending on their trait differences with the dominant species. Simultaneously managing the dispersion, evenness, and rarity in multispecies assemblages could be used to design assemblages aimed at maximizing multifunctionality independently of the biome, the identity of dominant species, or the range of trait values considered. Functional evenness and rarity offer promise to improve the management of terrestrial ecosystems and to limit plant disease risks.
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    Chapter 23: impacts of deforestation and climate change on biodiversity, ecological processes, and environmental adaptation
    (2021-11-12)
    This chapter presents observed and predicted impacts of climate change on Amazonian ecosystems, focusing on biodiversity, ecosystem services, carbon cycling, fisheries, and emissions from biomass burning. It also considers climate and land-use change feedbacks and highlights knowledge gaps to better understand these complex interactions.
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    Woody Plant Taxonomic, Functional, and Phylogenetic Diversity Decrease Along Elevational Gradients in Andean Tropical Montane Forests: Environmental Filtering and Arrival of Temperate Taxa
    (Cold Spring Harbor Laboratory, 2023-08-06)
    Aim Mountains are paramount for exploring biodiversity patterns and their causes due to the rich mosaic of topographies and climates encompassed over short geographical distances. Biodiversity changes along elevational gradients have traditionally been explored in terms of taxonomic diversity, but other aspects must be considered. For first time, we simultaneously assessed elevational trends in the taxonomic, functional, and phylogenetic diversity of woody plants in Andean tropical montane forests (TMFs) and explored their underlying ecological and evolutionary causing processes. Location Tropical Andes Time period 2011/2012 and 2017/2019 Tropical Andes Major Taxa Woody plants Methods We investigated taxonomic, functional, and phylogenetic diversity along four transects (traversing ca . 2,200 m altitudinal gradients) encompassing 114 0.1 ha plots across a broad latitudinal range ( ca . 10°). We used Hill numbers to quantify differences in the abundance-based diversity of 37,869 woody plant individuals with DBH ≥ 2.5 cm. Results Taxonomic, functional, and phylogenetic diversity decreased as elevation increased. The decrease was less pronounced for Hill numbers of higher orders. The only exception was a slight increase in phylogenetic diversity when more weight was given to dominant species. These results were consistent between transects. Main conclusions The decrease in taxonomic and functional diversity with elevation might be due to an environmental filtering process where the increasingly harsher conditions towards highlands exclude species and functional strategies. Besides, the differences in the steepness of the decrease between Hill orders suggest that rare species contribute disproportionately to functional diversity. The shifting elevational trend in the phylogenetic diversity between Hill orders indicates a greater than previously considered influence in central tropical Andean highlands of species originated in lowlands with strong niche conservatism relative to distantly related temperate lineages. This could be explained by a decreasing presence and abundance of extratropical taxa towards the central Andes relative to northern or southern Andes. BIOSKETCH Guillermo Bañares-de-Dios is a plant ecologist with interests in community assembly, biodiversity patterns, and global change. He completed his PhD in 2020 and belongs to “Grupo de Ecología Tropical”, an international network of researchers from different institutions with broad interests in tropical biology ( http://www.grupoecologiatropical.com/?lang=en ). Currently he works as Project Manager implementing the European Pollinator Monitoring Scheme in Spain.
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    South American Mountain Ecosystems and Global Change–A Case Study for Integrating Theory and Field Observations for Land Surface Modelling and Ecosystem Management
    (Taylor and Francis Ltd., 2023-01-01)
    Background: Plot-based monitoring has yielded much information on the taxonomic diversity and carbon (C) storage in tropical lowland forests of the Amazon basin. This has resulted in an improved understanding of the relationship between lowland forest biomass dynamics and global change drivers, such as climate change and atmospheric CO2 concentration. Much less attention has been paid to the mountain ecosystems of South America that comprise montane forests and alpine vegetation (páramo, puna, high Andean grasslands, wetlands, and alpine heath). This vegetation complex provides a variety of ecosystem services and forms a natural laboratory along various physiographic, geological and evolutionary history/biogeography, and land use history gradients. Aims: Here, we review existing empirical understanding and model-based approaches to quantify the contribution of mountain ecosystems to ecosystem service provision in the rapidly changing socioecological setting of the South American mountains. The objective of this paper is to outline a broad road map for the implementation of mountain vegetation into dynamic global vegetation models (DGVM) for use in Earth System Models (ESM), based on our current understanding of their structure and function and of their responsiveness to global change drivers. We also identify treeline processes, critical in mountain ecosystems, as key missing elements in DGVMs/ESMs, and thus explore in addition a treeline model. Methods: Stocktaking of the availability of empirical data was undertaken from eight research sites along the Andes and in south-eastern Brazil. Out of eight sites, two (one each in Venezuela and Brazil) had some climate, ecological and ecophysiological data potentially suitable to parametrise a DGVM. Tree biomass data were available for six sites. A preliminary assessment of the Joint UK Land Environment Simulator (JULES) DGVM was made to identify gaps in available data and their impacts on model parametrisation and calibration. Additionally, the potential climate-determined elevation of the treeline was modelled to check the DGVM for its ability to identify the transition between the montane forest and alpine vegetation. Results: Outcomes of the evaluation of the JULES land surface model identified the following key processes in montane forests: temperature-related decrease in net primary production, respiration, and allocation to above-ground biomass and increase in soil C stocks with elevation. There was a variable agreement between simulated biomass and those derived from field measurements via allometric equations. Conclusions: We identified major gaps between data availability and the needs for process-based modelling of South American mountain vegetation and its dynamics in DGVMs. To bridge this gap, we propose a transdisciplinary network, composed of members of the theoretical/modelling and empirical scientific communities, to study the natural dynamics of mountain ecosystems and their responses to global change drivers locally, regionally and at the continental scale, within a social-ecological system framework. The work presented here forms the basis for the design of data collection from field measurements and instrumental monitoring stations to parametrise and verify DGVMs. The network is designed to collaborate with and complement existing long-term research initiatives in the region and will adopt existing standard field protocols. Complementary protocols will ensure compatibility between field data collection and data needed for process-based and empirical models.