Latitudinal and altitudinal patterns of plant community diversity on mountain summits across the tropical Andes

The high tropical Andes host one of the richest alpine floras of the world, with exceptionally high levels of endemism and turnover rates. Yet, little is known about the patterns and processes that structure altitudinal and latitudinal variation in plant community diversity. Herein we present the first continental-scale comparative study of plant community diversity on summits of the tropical Andes. Data were obtained from 792 permanent vegetation plots (1 m2) within 50 summits, distributed along a 4200 km transect; summit elevations ranged between 3220 and 5498 m a.s.l. We analyzed the plant community data to assess: 1) differences in species abundance patterns in summits across the region, 2) the role of geographic distance in explaining floristic similarity and 3) the importance of altitudinal and latitudinal environmental gradients in explaining plant community composition and richness. On the basis of species abundance patterns, our summit communities were separated into two major groups: Puna and Páramo. Floristic similarity declined with increasing geographic distance between study-sites, the correlation being stronger in the more insular Páramo than in the Puna (corresponding to higher species turnover rates within the Páramo). Ordination analysis (CCA) showed that precipitation, maximum temperature and rock cover were the strongest predictors of community similarity across all summits. Generalized linear model (GLM) quasi-Poisson regression indicated that across all summits species richness increased with maximum air temperature and above-ground necromass and decreased on summits where scree was the dominant substrate. Our results point to different environmental variables as key factors for explaining vertical and latitudinal species turnover and species richness patterns on high Andean summits, offering a powerful tool to detect contrasting latitudinal and altitudinal effects of climate change across the tropical Andes.Fil: Cuesta, Francisco. University of Amsterdam; Países BajosFil: Muriel, Priscilla. Pontificia Universidad Catolica del Ecuador; EcuadorFil: Llambí, Luis Daniel. Universidad de Los Andes; VenezuelaFil: Halloy, Stephan. Universidad Nacional de Chilecito; ArgentinaFil: Aguirre, Nikolay. Universidad Nacional de Loja; EcuadorFil: Beck, Stephan. Universidad Mayor de San Andrés; BoliviaFil: Carilla, Julieta. Universidad Nacional de Tucumán; Argentina. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Meneses, Rosa Isela. Universidad Mayor de San Andrés; BoliviaFil: Cuello, Ana Soledad. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Grau, Alfredo. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Gámez, Luis E.. Universidad de Los Andes; VenezuelaFil: Irazábal, Javier. Pontificia Universidad Catolica del Ecuador; EcuadorFil: Jácome, Jorge. Pontificia Universidad Javeriana; ColombiaFil: Jaramillo, Ricardo. Pontificia Universidad Catolica del Ecuador; EcuadorFil: Ramírez, Lirey. Universidad de Los Andes; VenezuelaFil: Samaniego, Natalia. Universidad Nacional de Loja; EcuadorFil: Suárez Duque, David. Giz; EcuadorFil: Thompson, Natali. Universidad Mayor de San Andrés; BoliviaFil: Tupayachi, Alfredo. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Viñas, Paul. Naturaleza y Cultura Internacional; PerúFil: Yager, Karina. National Aeronautics and Space Administration. Goddart Institute for Space Studies; Estados UnidosFil: Becerra, María T.. Earth Innovation Institute; ColombiaFil: Pauli, Harald. Universitat Fur Bodenkultur Wien; AustriaFil: Gosling, William D.. University of Amsterdam; Países Bajo

Southern Highlands: Fungal Endosymbiotic Associations

In South America (SA), Highlands above-treeline stretch along 7000 km in a North-South direction, occupying almost 694,000 km2, most of it is located in the Andean region except for 34,500 km2 in the Chaco region. In these Highlands are represented very particular ecoregions and phytogeographic areas in desertic, arid and semiarid biomes with characteristic vegetations composed by endemic plants. These Highlands are completely different from the ones found in Europe and Asia due to their proper biodiversity, climate, geographic position, geologic origin, and biogeography. Highlands in SA are suffering soil erosion, a retraction of their areas due to the advance of the agricultural-livestock frontiers and overgrazing, environmental deterioration by firewood extraction and the accumulation of mining toxic waste. Mountain ecosystems are huge-natural-environmental laboratories where it is possible to study important ecological unresolved hypothesis. The study of fungal-root-endophytes (mycorrhizal and dark-septate fungi), their colonization to native plants and how to enhance the resilience of soil ecosystems deserves special attention. Studies on fungal-root-endophytes have been carried out extensively worldwide; however, the research in Highlands are still scant around the world, especially in SA. This Chapter reviews and discusses fungal-root-endophytes colonization in Highlands of SA, and compared them to the worldwide knowledge.Fil: Lugo, Mónica Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Menoyo, Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentin

Systematic review of quantitative imaging biomarkers for neck and shoulder musculoskeletal disorders

© 2017 The Author(s). Background: This study systematically summarizes quantitative imaging biomarker research in non-traumatic neck and shoulder musculoskeletal disorders (MSDs). There were two research questions: 1) Are there quantitative imaging biomarkers associated with the presence of neck and shoulder MSDs?, 2) Are there quantitative imaging biomarkers associated with the severity of neck and shoulder MSDs? Methods: PubMed and SCOPUS were used for the literature search. One hundred and twenty-five studies met primary inclusion criteria. Data were extracted from 49 sufficient quality studies. Results: Most of the 125 studies were cross-sectional and utilized convenience samples of patients as both cases and controls. Only half controlled for potential confounders via exclusion or in the analysis. Approximately one-third reported response rates. In sufficient quality articles, 82% demonstrated at least one statistically significant association between the MSD(s) and biomarker(s) studied. The literature synthesis suggested that neck muscle size may be decreased in neck pain, and trapezius myalgia and neck/shoulder pain may be associated with reduced vascularity in the trapezius and reduced trapezius oxygen saturation at rest and in response to upper extremity tasks. Reduced vascularity in the supraspinatus tendon may also be a feature in rotator cuff tears. Five of eight studies showed an association between a quantitative imaging marker and MSD severity. Conclusions: Although research on quantitative imaging biomarkers is still in a nascent stage, some MSD biomarkers were identified. There are limitations in the articles examined, including possible selection bias and inattention to potentially confounding factors. Recommendations for future studies are provided