Biology subjects

Tello, J. S.

Publications and source records attributed to Tello, J. S..

3 recordsLinked to original sources

bioRxiv2023

Ecological metabolomics of tropical tree communities across an elevational gradient: Implications for chemically-mediated biotic interactions and species diversity

Seminal hypotheses in ecology and evolution postulate that stronger and more specialized biotic interactions contribute to higher species diversity at lower elevations and latitudes. Plant-chemical defenses mediate biotic interactions between plants and their natural enemies and provide a highly dimensional trait space in which chemically mediated niches may facilitate plant species coexistence. However, the role of chemically mediated biotic interactions in shaping plant communities remains largely untested across large-scale ecological gradients. To test this hypothesis, we used ecological metabolomics to quantify the chemical dissimilarity of foliar metabolomes among 473 tree species (906 unique species-plot combinations) in 16 tropical tree communities along an elevational gradient in Madidi National Park, Bolivia. We predicted that chemical dissimilarity among co-occurring tree species would be greater, and chemical phylogenetic signal lower, in communities with greater tree species richness and warmer, wetter, and less-seasonal climates, as pressure from natural enemies is likely to be greater in these locales. Further, we predicted that these relationships should be especially pronounced for secondary metabolites derived from biosynthetic pathways known to include anti-herbivore and antimicrobial defenses than for primary metabolites. We found that median chemical dissimilarity among tree species with respect to all metabolites and secondary metabolites increased with tree species richness, decreased with elevation, and increased along a principal component of climatic variation that reflected increasing temperature and precipitation and decreasing seasonality. In contrast, median chemical dissimilarity among tree species with respect to primary metabolites was unrelated to tree species richness, elevation, or the principal component of climatic variation. Furthermore, phylogenetic signal of secondary and primary metabolites decreased with tree species richness. Among tree communities in moist forests, phylogenetic signal of secondary metabolites also increased with elevation and decreased with the temperature and precipitation. Our results support the hypothesis that chemically mediated biotic interactions shape elevational diversity gradients by imposing stronger selection for interspecific divergence in plant chemical defenses in warmer, wetter, and more stable climates. Our study also illustrates the promise of ecological metabolomics in the study of biogeography, community ecology, and complex species interactions in high-diversity ecosystems.

ecology↗

bioRxiv2023

Elevational Range Sizes of Woody plants Increase with Climate Variability in the Tropical Andes

AimThe climate variability hypothesis proposes that species subjected to wide variation in climatic conditions will evolve wider niches, resulting in larger distributions. We test this hypothesis in tropical plants across a broad elevational gradient; specifically, we use a species-level approach to evaluate whether elevational range sizes are explained by the levels of thermal variability experienced by species. LocationCentral Andes Time periodPresent day Major taxa studiedWoody plants MethodsCombining data from 479 forest plots, we determined the elevational distributions of nearly 2300 species along an elevational gradient ([~]209 - 3800 m). For each species, we calculated the maximum annual variation in temperature experienced across its elevational distribution. We used phylogenetic generalized least square models to evaluate the effect of thermal variability on range size. Our models included additional covariates that might affect range size: body size, local abundance, mean temperature and total precipitation. We also considered interactions between thermal variability and mean temperature or precipitation. To account for geometric constraints, we repeated our analyses with a standardized measure of range size, calculated by comparing observed range sizes with values obtained from a null model. ResultsOur results supported the main prediction of the climate variability hypothesis. Thermal variability had a strong positive effect on the range size, with species exposed to higher thermal variability having broader elevational distributions. Body size and local abundance also had positive, yet weak effects, on elevational range size. Furthermore, there was a strong positive interaction between thermal variability and mean annual temperature. Main conclusionsThermal variability had an overriding importance in driving elevational range sizes of woody plants in the Central Andes. Moreover, the relationship between thermal variability and range size might be even stronger in warmer regions, underlining the potential vulnerability of tropical montane floras to the effects of global warming.

ecology↗

bioRxiv2021

Relative effects of edaphic conditions and climate on palm communities in the Central Andes

Palms (family Arecaceae) are conspicuous and structural elements in forests ecosystems of tropical regions and mountain forests in South America. Additionally, many species of palms are culturally and economically important to human populations. Because of their ecological and ethnobotanical significance, understanding the drivers of palm distribution and diversity is critical. However, most past research has focused in tropical lowland palm communities, while our understanding of montane tropical palm ecology and biogeography is comparatively lacking. We investigate the environmental factors that influence patterns of richness, composition, and abundance of palms in the Central Andes. In particular, we are interested in the relative effects that soil edaphic conditions and climate have on palm community structure. For these analyses, we used a network of 88 forest plots distributed along a broad elevational gradient (1,000 - 3,200 meters), which are part of the Madidi Project in north-western Bolivia. We carried out palm community-level analysis, as well as species-specific analyses for each of the 16 most common species. We found that soils and climate contribute differentially to shaping Andean palm diversity and distributions. We found that soils explain more variation in species composition (14.4%) than climate (3.45%), but that climate explains more variation in species richness (13%) than soils (6.1%). Moreover, species-specific analyses reveal that there is great variation in how different common species respond to their abiotic environment. Our results contribute to understanding the drivers of biodiversity for a highly important group of plants in one of the most important hotspots for biodiversity. RESUMENEn el neotropico, las palmeras (Arecaceae) son un grupo diverso y abundante de plantas que constituyen elementos estructurales en bosques tropicales tanto de tierras bajas como de montana. Ademas, muchas especies de palmeras son culturalmente y economicamente importantes para muchas poblaciones humanas. Debido a su importancia ecologica y etnobotanica, entender los mecanismos que controlan la diversidad y la distribucion de las palmeras es extremadamente importante. Sin embargo, la mayoria de la investigacion hasta el momento se ha enfocado en comunidades de palmeras de tierras bajas, mientras que la ecologia y biogeografia de las palmeras de montanas es relativamente poco entendida. En este estudio, nosotros investigamos los factores ambientales que influencian la riqueza, composicion y abundancia de palmeras en los Andes Centrales. En particular, estamos interesados en entender los efectos relativos de las condiciones edaficas del suelo y el clima en la estructura de comunidades de palmeras. Para nuestros analisis, usamos una red de 88 parcelas de arboles distribuidas a lo largo de un gradiente elevacional (1,000 - 3,200 metros), la misma que es parte del Proyecto Madidi en Bolivia. Encontramos que el suelo y el clima tienen efectos diferentes. El suelo explica mas variacion en la composicion de especies (14.4%) que el clima (3.45%), pero el clima explica mas variacion en la riqueza de especies (13%) que los suelos (6.1%). Ademas, analisis independientes para las 16 especies mas comunes demuestran gran variacion en como cada especie responde a las condiciones ambientales. Nuestros resultados contribuyen a entender los factores que controlan la diversidad de un grupo importante de plantas en una de las regiones mas diversas del planeta.

ecology↗