Browsing by Autor "Julieta Carilla"

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Author Correction: Mature Andean forests as globally important carbon sinks and future carbon refuges
(Nature Portfolio, 2021) Álvaro Duque; Miguel A. Peña; Francisco Cuesta; Sebastian González‐Caro; Peter G. Kennedy; Oliver L. Phillips; Marco Calderón-Loor; Cecilia Blundo; Julieta Carilla; Leslie Cayola
Elevation and latitude drives structure and tree species composition in Andean forests: Results from a large-scale plot network
(Public Library of Science, 2020) Agustina Malizia; Cecilia Blundo; Julieta Carilla; Oriana Osinaga Acosta; Francisco Cuesta; Álvaro Duque; Nikolay Aguirre; Zhofre Aguirre Mendoza; Michele Ataroff; Selene Báez
Our knowledge about the structure and function of Andean forests at regional scales remains limited. Current initiatives to study forests over continental or global scales still have important geographical gaps, particularly in regions such as the tropical and subtropical Andes. In this study, we assessed patterns of structure and tree species diversity along ~ 4000 km of latitude and ~ 4000 m of elevation range in Andean forests. We used the Andean Forest Network (Red de Bosques Andinos, https://redbosques.condesan.org/) database which, at present, includes 491 forest plots (totaling 156.3 ha, ranging from 0.01 to 6 ha) representing a total of 86,964 identified tree stems ≥ 10 cm diameter at breast height belonging to 2341 identified species, 584 genera and 133 botanical families. Tree stem density and basal area increases with elevation while species richness decreases. Stem density and species richness both decrease with latitude. Subtropical forests have distinct tree species composition compared to those in the tropical region. In addition, floristic similarity of subtropical plots is between 13 to 16% while similarity between tropical forest plots is between 3% to 9%. Overall, plots ~ 0.5-ha or larger may be preferred for describing patterns at regional scales in order to avoid plot size effects. We highlight the need to promote collaboration and capacity building among researchers in the Andean region (i.e., South-South cooperation) in order to generate and synthesize information at regional scale.
Historical Assembly of Andean Tree Communities
(Multidisciplinary Digital Publishing Institute, 2023) Sebastian González‐Caro; J. Sebastián Tello; Jonathan A. Myers; Kenneth J. Feeley; Cecilia Blundo; Marco Calderón-Loor; Julieta Carilla; Leslie Cayola; Francisco Cuesta; William Farfán-Ríos
Patterns of species diversity have been associated with changes in climate across latitude and elevation. However, the ecological and evolutionary mechanisms underlying these relationships are still actively debated. Here, we present a complementary view of the well-known tropical niche conservatism (TNC) hypothesis, termed the multiple zones of origin (MZO) hypothesis, to explore mechanisms underlying latitudinal and elevational gradients of phylogenetic diversity in tree communities. The TNC hypothesis posits that most lineages originate in warmer, wetter, and less seasonal environments in the tropics and rarely colonize colder, drier, and more seasonal environments outside of the tropical lowlands, leading to higher phylogenetic diversity at lower latitudes and elevations. In contrast, the MZO hypothesis posits that lineages also originate in temperate environments and readily colonize similar environments in the tropical highlands, leading to lower phylogenetic diversity at lower latitudes and elevations. We tested these phylogenetic predictions using a combination of computer simulations and empirical analyses of tree communities in 245 forest plots located in six countries across the tropical and subtropical Andes. We estimated the phylogenetic diversity for each plot and regressed it against elevation and latitude. Our simulated and empirical results provide strong support for the MZO hypothesis. Phylogenetic diversity among co-occurring tree species increased with both latitude and elevation, suggesting an important influence on the historical dispersal of lineages with temperate origins into the tropical highlands. The mixing of different floras was likely favored by the formation of climatically suitable corridors for plant migration due to the Andean uplift. Accounting for the evolutionary history of plant communities helps to advance our knowledge of the drivers of tree community assembly along complex climatic gradients, and thus their likely responses to modern anthropogenic climate change.
Latitudinal and altitudinal patterns of plant community diversity on mountain summits across the tropical Andes
(Wiley, 2016) Francisco Cuesta; Priscilla Muriel; Luis D. Llambí; Stephan Halloy; Nikolay Aguirre; Stephan Beck; Julieta Carilla; Rosa Isela Meneses; Soledad Cuello; Alfredo Grau
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 m 2 ) 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.
Mature Andean forests as globally important carbon sinks and future carbon refuges
(Nature Portfolio, 2021) Álvaro Duque; Miguel A. Peña; Francisco Cuesta; Sebastian González‐Caro; Peter G. Kennedy; Oliver L. Phillips; Marco Calderón-Loor; Cecilia Blundo; Julieta Carilla; Leslie Cayola
Thermal niche traits of high alpine plant species and communities across the tropical Andes and their vulnerability to global warming
(Wiley, 2019) Francisco Cuesta; Carolina Tovar; Luis D. Llambí; William D. Gosling; Stephan Halloy; Julieta Carilla; Priscilla Muriel; Rosa Isela Meneses; Stephan Beck; Carmen Ulloa Ulloa
Abstract Aim The climate variability hypothesis (CVH) predicts that locations with reduced seasonal temperature variation select for species with narrower thermal ranges. Here we (a) test the CVH by assessing the effect of latitude and elevation on the thermal ranges of Andean vascular plant species and communities, and (b) assess tropical alpine plants vulnerability to warming based on their thermal traits. Location High tropical Andes. Taxon Vascular plants. Methods Temperature data for 505 vascular plant species from alpine communities on 49 summits, were extracted from 29,627 georeferenced occurrences. Species thermal niche traits (TNTs) were estimated using bootstrapping for: minimum temperature, optimum (mean) temperature and breadth (maximum‐minimum). Plant community‐weighted scores were estimated using the TNTs of their constituent species. CVH was tested for species, biogeographical species groups and communities. Vulnerability to global warming was assessed for species, biogeographical species groups and communities. Results Species restricted to the equator showed narrower thermal niche breadth than species whose ranges stretch far from the equator, however, no difference in niche breadth was found across summits’ elevation. Biogeographical species groups distributed close to the equator and restricted to alpine regions showed narrower niche breadth than those with broader ranges. Community‐weighted scores of thermal niche breadth were positively related to distance from equator but not to elevation. Based on their TNTs, species restricted to equatorial latitudes and plant communities dominated by these species were identified as the most vulnerable to the projected 1.5°C warming, due to a potentially higher risk of losing thermal niche space. Main conclusions Our study confirms that the CVH applies to high tropical Andean plant species and communities, where latitude has a strong effect on the thermal niche breadth. TNTs are identified as suitable indicators of species’ vulnerability to warming and are suggested to be included in long‐term biodiversity monitoring in the Andes.