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Item type:Publication, The evolutionary assembly of forest communities along environmental gradients: recent diversification or sorting of pre-adapted clades?(Cold Spring Harbor Laboratory, 2020-12-22)Summary Biogeographic events occurring in the deep past can contribute to the structure of modern ecological communities. However, little is known about how the emergence of environmental gradients shape the evolution of species that underlie community assembly. In this study, we address how the creation of novel environments lead to community assembly via two non-mutually exclusive processes: 1) the immigration and ecological sorting of pre-adapted clades (ISPC), and 2) recent adaptive diversification (RAD). We study these processes in the context of the elevational gradient created by the uplift of the Central Andes. We develop a novel approach and method based on the decomposition of species turnover into within- and among-clade components, where clades correspond to lineages that originated before mountain uplift. Effects of ISPC and RAD can be inferred from how components of turnover change with elevation. We test our approach using data from over 500 Andean forest plots. We found that species turnover between communities at different elevations is dominated by the replacement of clades that originated before the uplift of the Central Andes. Our results suggest that immigration and sorting of clades pre-adapted to montane habitats is the primary mechanism shaping communities across elevations.1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Influence of Taxonomy and Environment on Leaf Trait Variation Along Tropical Abiotic Gradients(Frontiers Media S.A., 2020-03-03)Deconstructing functional trait variation and co-variation across a wide range of environmental conditions should increase the mechanistic understanding of community assembly processes and improve current parameterization of dynamic vegetation models. Here, we present a study that deconstructs leaf trait variation and co-variation to iithin-species, taxonomic-interspecific, and plot-environment components comparing three tropical environmental gradients in Peru, Brazil and Ghana. We measured photosynthetic, chemical and structural leaf traits using a standardized sampling protocol, totalling more than 1,000 individuals belonging to 367 species sampled. Variation associated with the whole interspecific taxonomic component (species+genus+family) for most traits was relatively consistent across environmental gradients, but intra-specificwithin-species variation and the plot-environment variation was strongly dependent on the environmental gradient. Trait-trait co-variation was also strongly linked to the environmental gradient where the traits were measured, although some traits had consistent co-variation components irrespective of environmental gradient. Our results demonstrate that filtering along gradients is mostly expressed through trait intra- and interspecifictaxonomic variation, but that trait co-variation is strongly dependent on the local environment, and thus global trait co-variation relationships might not always apply at smaller scales. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Reduced tree density and basal area in Andean forests are associated with bamboo dominance(Elsevier, 2020-10-13)Forest structure and composition play an essential role in determining the carbon storage capacity of tropical forests. Andean forests, with great potential for carbon accumulation, include large expanses of high-density woody bamboo communities. Woody bamboos can potentially alter forest structure, composition and dynamics and thus can affect carbon storage capacity; however, they are commonly excluded from forest monitoring and modelling. With the aim of documenting patterns of bamboo abundance and disentangling its association with forest structure, we carried out a bamboo census in seven 1-ha long-term forest monitoring plots situated across a large elevation gradient (1000–3600 m a.s.l.) in the Peruvian Andes. We determined that bamboo is a dominant plant group in the study area. In every plot, bamboos were the most common genera in terms of number of stems, and in two of the plots bamboo species were among those with the greatest basal area. We used a combination of Generalized linear mixed models (GLMM) and structural equation modelling (SEM) to hypothesize a causal framework and determine the direction and size of the effects of bamboo abundance (basal area) on number of individual trees, total tree basal area, mean tree basal area, mean tree growth rate and tree mortality rate. We found an overall negative association between bamboo abundance and total tree basal area driven mainly by reduced tree density (directly and indirectly mediated by an increase in tree mortality). However, the decrease in tree density and the increase in tree mortality are also associated with a small increase in tree diameter (mean tree basal area). Overall, the negative association between bamboo abundance and tree basal area suggests a lower biomass accumulation and thus a lower carbon storage capacity of trees in Andean forests where bamboo is dominant. Our results, which show the importance of bamboo in determining forest function, highlight the need for including bamboo in monitoring efforts and modeling studies. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Functional susceptibility of tropical forests to climate change(Nature Research, 2022-07-01)Tropical forests are some of the most biodiverse ecosystems in the world, yet their functioning is threatened by anthropogenic disturbances and climate change. Global actions to conserve tropical forests could be enhanced by having local knowledge on the forestsʼ functional diversity and functional redundancy as proxies for their capacity to respond to global environmental change. Here we create estimates of plant functional diversity and redundancy across the tropics by combining a dataset of 16 morphological, chemical and photosynthetic plant traits sampled from 2,461 individual trees from 74 sites distributed across four continents together with local climate data for the past half century. Our findings suggest a strong link between climate and functional diversity and redundancy with the three trait groups responding similarly across the tropics and climate gradient. We show that drier tropical forests are overall less functionally diverse than wetter forests and that functional redundancy declines with increasing soil water and vapour pressure deficits. Areas with high functional diversity and high functional redundancy tend to better maintain ecosystem functioning, such as aboveground biomass, after extreme weather events. Our predictions suggest that the lower functional diversity and lower functional redundancy of drier tropical forests, in comparison with wetter forests, may leave them more at risk of shifting towards alternative states in face of further declines in water availability across tropical regions. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Improving landscape-scale productivity estimates by integrating trait-based models and remotely-sensed foliar-trait and canopy-structural data(John Wiley and Sons Inc, 2022-08-01)Assessing the impacts of anthropogenic degradation and climate change on global carbon cycling is hindered by a lack of clear, flexible and easy-to-use productivity models along with scarce trait and productivity data for parameterizing and testing those models. We provide a simple solution: a mechanistic framework (RS-CFM) that combines remotely-sensed foliar-trait and canopy-structural data with trait-based metabolic theory to efficiently map productivity at large spatial scales. We test this framework by quantifying net primary productivity (NPP) at high-resolution (0.01-ha) in hyper-diverse Peruvian tropical forests (30040 hectares) along a 3322-m elevation gradient. Our analysis captures hotspots and elevational shifts in productivity more accurately and in greater detail than alternative empirical- and process-based models that use plant functional types. This result exposes how high-resolution, location-specific variation in traits and light competition drive variability in productivity, opening up possibilities to fully harness remote sensing data and reliably scale up from traits to map global productivity in a more direct, efficient and cost-effective manner. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, 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.3 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Effects of Human Population Density on Trophic Interactions Are Contingent Upon Latitude(Cold Spring Harbor Laboratory, 2023-08-23)Aim: Studies conducted at a global scale are necessary to make general conclusions on the effect of urbanization on trophic interactions and explore how these effects change along latitudinal gradients. Since biotic interactions are more intense at lower latitudes, we predict that the intensity of trophic interactions will decrease in response to urbanization (quantified by human population density), with higher impacts of urbanization at higher latitudes. Location: Global (881 study sites). Time period: 2000-2021. Major taxa studied: Birds, arthropods and woody plants. Methods: We compiled global data on insect herbivory and bird predation from individual studies using similar methodologies, and fitted generalized linear mixed models to test the effect of human population density, latitude and their interaction on these two response variables. Results: The intensity of herbivory and predation decreased with the increase of human population density at lower latitudes, remained unaffected at intermediate latitudes, and increased at higher latitudes. Main conclusions: The effect of human population density on insect herbivory and bird predation consistently varies across latitudes, with a reversal of the pattern at high versus low latitudes.