Browsing by Autor "Francisco Cuesta"

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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
Plant dispersal strategies of high tropical alpine communities across the Andes
(Wiley, 2020) Carolina Tovar; Inga M. Melcher; Buntarou Kusumoto; Francisco Cuesta; A.M. Cleef; Rosa Isela Meneses; Stephan Halloy; Luis D. Llambí; Stephan Beck; Priscilla Muriel
Abstract Dispersal is a key ecological process that influences plant community assembly. Therefore, understanding whether dispersal strategies are associated with climate is of utmost importance, particularly in areas greatly exposed to climate change. We examined alpine plant communities located in the mountain summits of the tropical Andes across a 4,000‐km latitudinal gradient. We investigated species dispersal strategies and tested their association with climatic conditions and their evolutionary history. We used dispersal‐related traits (dispersal mode and growth form) to characterize dispersal strategies for 486 species recorded on 49 mountain summits. Then we analysed the phylogenetic signal of traits and investigated the association between dispersal traits, phylogeny, climate and space using structural equation modelling and fourth‐corner analysis together with RLQ ordination. A median of 36% species in the communities was anemochorous (wind‐dispersed) and herbaceous. This dispersal strategy was followed by the barochory‐herb combination (herbaceous with unspecialized seeds, dispersed by gravity) with a median of 26.3% species in the communities. The latter strategy was common among species with distributions restricted to alpine environments. While trait states were phylogenetically conserved, they were significantly associated with a temperature gradient. Low minimum air temperatures, found at higher latitudes/elevations, were correlated with the prevalence of barochory and the herb growth form, traits that are common among Caryophyllales, Brassicaceae and Poaceae. Milder temperatures, found at lower latitudes/elevations, were associated with endozoochorous, shrub species mostly from the Ericaceae family. Anemochorous species were found all along the temperature gradient, possibly due to the success of anemochorous Compositae species in alpine regions. We also found that trait state dominance was more associated with the climatic conditions of the summit than with community phylogenetic structure. Although the evolutionary history of the tropical Andean flora has also shaped dispersal strategies, our results suggest that the environment had a more predominant role. Synthesis . We showed that dispersal‐related traits are strongly associated with a gradient of minimum air temperatures in the Andes. Global warming may weaken this key filter at tropical alpine summits, potentially altering community dispersal strategies in this region and thus, plant community structure and composition.
Spatiotemporal distributions and potential sources of sediment and waterborne heavy metals in lowland lakes and rivers of the Ecuadorian Amazon
(Springer Science+Business Media, 2025) José Vicente Montoya; Blanca Ríos‐Touma; Nathan K. Lujan; Fernando Sánchez Sánchez; Adrián Proaño; Esperanza Beltrán Tejera; Karina Jimenes-Vargas; Luzmila Sánchez; Francisco Cuesta
Strategies of diaspore dispersal investment in Compositae: the case of the Andean highlands
(Oxford University Press, 2023) Carolina Tovar; Lucia Hudson; Francisco Cuesta; Rosa Isela Meneses; Priscilla Muriel; Oriane Hidalgo; Luis Palazzesi; Carlos Suarez Ballesteros; Eleanor Hammond Hunt; Mauricio Diazgranados
Small achenes and high diaspore dispersal investment dominate among high-Andean Compositae, traits typical of mostly three tribes of African origin; but traits are also correlated with the environmental gradients within the high-Andean grasslands. Our results also suggest that diaspore dispersal investment is likely to shape species distribution patterns in naturally fragmented habitats.
The metropolitan parks of Quito as important carbon sinks
(2024) Laura Cifuentes Rodríguez; Francisco Cuesta
Abstract Despite the importance of urban forests as important carbon sinks, studies in Ecuador have yet to assess their potential to store carbon. We assessed the carbon stored in the aboveground biomass (AGB) and annual rates of AGB accumulation in the Guangüiltagua Metropolitan Park (GMP) and the Southern Metropolitan Park (SMP). We installed 11 plots per park of 0.063 ha, where we surveyed all stems with a diameter at breast height (DBH) ≥2.5 cm. To estimate annual increments in AGB, we installed dendrometer bands on 10% of the total stems recorded in each plot (only in stems with ≥10 cm DBH). We measured the dendrometer band segment increase every 4 months from September 2019 to October 2020. Our results show that the GMP stores 171 ± 96 Mg C ha−1, significantly higher than the amount of carbon storage recorded in the SMP (100 ± 41 Mg C ha−1). In contrast, the GMP sequestered 3.30 ± 1.71 Mg C ha year−1, while the SMP sequestered an average of 4.45 ± 2.63 Mg C ha year−1. At the landscape scale, the SMP contains 0.072 Tg C (0.058–0.091, 95% CI), while the GMP contains a reservoir of 0.096 Tg C (0.067–0.13, 95% CI). Likewise, the AGB in the SMP 3,165 Mg C year−1 (2209–4297, 95% CI), while that in the GMP sequestered 1859 Mg year−1 (1361–2430, 95% CI). Our results show that the metropolitan parks of Quito are important carbon sinks and constitute essential elements in mitigating climate change in urban spaces.
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.