Andes Research Articles

Unravelling the distribution of mycorrhizal plants in the Colombian páramos

AbstractThe tropicalpine páramo stands out as a unique biodiversity hotspot located in the northern Andes. Over the last decades, páramo plants and animals have been increasingly studied, yet a critical knowledge gap remains on their microbial ecology. Given the crucial importance of mycorrhiza in structural and functional communities, our study aimed to explore their geographic distribution in the Colombian páramos. Specifically, we used information about their host plants as a proxy and modelled their current distribution to unravel spatial patterns related to mycorrhizal status and mycorrhizal types. We constructed species distribution models for 440 vascular plant species representatives of the Colombian páramos using a combination of climatic and edaphic variables. Then we stacked the models following species classification into their mycorrhizal type: arbuscular, ectomycorrhizal, ericoid, orchid, and non-mycorrhizal. Our results suggest that the abundance of mycorrhizal species decreases with increasing elevation and in the west-to-east direction. The arbuscular type of mycorrhiza is chiefly dominant and spreads out widely throughout the Colombian páramos. The other types showed singular patterns, with (i) species having ericoid mycorrhiza being abundant in both the southern (Nariño–Putumayo) and the northern páramos (Sierra Nevada–Perijá); (ii) species with orchid mycorrhiza being abundant in the Western Cordillera and overall at low elevations, (iii) ectomycorrhizal species being absent, and (iv) non-mycorrhizal species being widely spread and reaching high elevations. Our study highlights the potentially high level of mycorrhization of this alpine system and contributes new spatial and environmental information towards a better understanding of mycorrhizal biogeography in tropical mountains.

Joining to the web. Predation of Heterophrynus sp. (Amblypygi: Phrynidae) on a catfish Astroblepus sp. (Siluriformes: Astroblepidae), in a premontane river of the northern Andes of Colombia

Riparian food webs are linked by cross-boundary resource fluxes, including the consumption of terrestrial invertebrates and vertebrates by fish and the consumption of aquatic vertebrates by terrestrial invertebrates, mostly arachnids. Amblypygids prey upon a wide array of vertebrates, but no records on fishes are known. Here we report an interesting predation event of an adult Heterophrynus sp., upon a catfish Astroblepus sp. in the Rio Manso, northern Andes of Colombia, and summarized the published information of trophic interactions of this river in a food web framework. A high prey-size ratio (0.87) respect to Heterophrynus sp., highlight that fishes could represent an important food item for amblypygids. This datum, besides other published before, indicates that the consumption of terrestrial and aquatic vertebrates by terrestrial invertebrates can be a substantial cross-boundary flux link in tropical montane streams deserving future ecological studies.

Spatial Connectivity Through Mountains and Deserts Drove South American Scorpions Dispersal

ABSTRACTAimThe aim of this study is to infer the geographic dispersal paths and the environmental conditions that shaped the historical biogeography of Brachistosternus scorpions in South America. We evaluated the role that altitude and aridity had on the geographic distance that each species dispersed from the location of the genus common ancestor. Based on the previous studies, we evaluated the hypothesis postulating that species geographic expansion was promoted by arid conditions in high altitudes.LocationSouth America.TaxonBrachistosternus genus.MethodsWe integrated two methodological approaches in this study, the phylogenetic Geographical model and the Conductance model, considering the uncertainty associated with the phylogenetic relationship and the species classification. The Geo model infers the locations of ancestral species in a phylogenetic tree, assuming a spherical space and using samples of georeferenced locations for every species as input data. It allows us to estimate the species dispersal routes and distances from the location of the genus common ancestor. The Conductance model is based on the circuit theory and infers the geographic route and distance of least resistance between an origin and destination point. We defined the origin as the location of the genus common ancestor obtained from the Geo model and a destination point as the current geographic location of each species. This model infers the geographic routes with the least cost of resistance for dispersal in a landscape of varying altitude and aridity. Finally, we evaluated the correlation between the two dispersal distances each species have moved from the location of the common ancestor, that is, the distance inferred from the Geo model and from the Conductance model.ResultsThe Geo model shows that Brachistosternus's geographical origin was most likely along the coast of south Peru, and central Chile. From this location, extant species dispersed thorough routes ranging from 873 to 2800 km in average. The Conductance model that considers the routes with least resistance to elevation and aridity simulated dispersal distances that are highly correlated with the species dispersal distances obtained from the Geo model.Main ConclusionsWe revealed the geographic dispersal routes, with the least resistance to the pressures imposed by changes in altitude and aridity, that 55 species of scorpions have probably followed in the last 30 million years in South America. These geographic routes that went along the Andean Mountains and the arid zones of South America shaped the current spatial distribution of the genus Brachistosternus.

Mapping Tropical Dry Forest Gradients in an Andean Region with High Environmental Variability

Tropical Dry Forest (TDF) is one of the most threatened terrestrial environments in the neotropics because of high rates of conversion to agriculture. Despite this high degree of threat, many regions lack detailed maps on the actual extent and boundaries of their TDFs, which is fundamental information for their conservation. We developed a methodological framework to map TDF at 10 m in regions where they grade into other forest types. The approach uses climate variables, altitude, soil properties, and remote sensing data (multispectral and SAR − Synthetic Aperture Radar-SAR imagery) to predict TDF in the Department of Caldas, Colombia. Accuracy of the resulting map was confirmed with field observations (Overall Accuracy = 0.88, Kappa = 0.73, Area Under the Receiver Operating Characteristics Curve = 0.87, and True Skill Statistic = 0.73). We estimated ∼ 54 km2 of TDF, which represents 9.2 % of its potential area of occurrence in the study area. TDF gradually transitions to Tropical Moist Forest (TMF) from two main low altitude river valleys to higher altitudes in the Andes Mountains. With modification, our methods could be applied for mapping TDF in other tropical regions.

Petrogenesis and tectonic setting of mafic magmatism within the Laguna Amarga Metamorphic Complex, Andes of Catamarca, Argentina: Insights into the opening of the Cuyania/Precordillera terrane from the Ouachita rift

Neoproterozoic crystalline basement rocks are exposed as fault-bounded blocks over the high Andes of Catamarca. The crystalline basement is stratigraphically grouped into the unique Laguna Amarga Metamorphic Complex and represents the northern extension of the Cuyania/Precordillera terrane. Tabular bodies of meta-mafic rocks are widespread in the basement interspersed within a thick sequence of meta-sedimentary rocks derived from siliciclastic, calc-silicate, and limestone protoliths. Overall, the geochemical characteristics of meta-mafic rocks are in the compositional range of Normal-Mid Ocean Ridge Basalt (Normal-MORB), reflecting a common depleted-mantle source with varying degrees of partial melting. While preserving the typical bulk chemistry of MORB magmatism, some mafic magma underwent differentiation at emplacement, leading to the development of high-Ti mafic rocks. New U-Pb zircon geochronology reveals three distinct age peaks, with two coinciding with ages identified in the metasedimentary host rocks. The dominant Mesoproterozoic age cluster is linked to inherited zircon crystals assimilated within a single meta-mafic rock. In contrast, zircon ages from the late Ordovician to early Devonian are attributed to metamorphic overgrowths. Notably, the third age cluster, delineates a Late Neoproterozoic magmatic event, indicating the temporal span of mafic magmatism. The finding agrees with the best available age (576 ± 17 Ma) for mafic magmatism on the Precordillera Mafic-Ultramafic Belt. Stratigraphic relationships and geochemical fingerprints enable correlation among the meta-mafic rocks from Laguna Amarga, tracing a belt of mafic magmatism with an oceanic affinity that extends southward. Building upon previous works, this study reaffirms that the rift-drift transition of the Cuyania/Precordillera terrane, linked to the Ouachita rift opening from southeastern Grenville, evolved during the latest Neoproterozoic.

Unveiling a novel exopolysaccharide produced by Pseudomonas alcaligenes Med1 isolated from a Chilean hot spring as biotechnological additive

Exopolysaccharides (EPSs), a constitutive part of bacterial biofilm, act as a protecting sheath to the extremophilic bacteria and are of high industrial value. In this study, we elucidate a new EPS produced by thermotolerant (growth from 34–44 °C) strain Pseudomonas alcaligenes Med1 from Medano hot spring (39.1 °C surface temperature, pH 7.1) located in the Central Andean Mountains of Chile. Bacterial growth was screened for temperature tolerance (10–60 °C) to confirm the thermotolerance behaviour. Physicochemical properties of the EPS were characterized by different techniques: Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy (SEM-EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). Whole genome of P. alcaligenes Med1 has also been studied in detail to correlate the structural and functional characteristics with genomic insight. The EPS demonstrated amorphous surface roughness composed of evenly distributed macromolecular lumps composed of mainly carbon and oxygen. The monosaccharide analysis has shown the presence of glucose, galactose, and mannose sugars at different ratios. TGA revealed the high thermal stability (315.3 °C) of the polysaccharide. The GPC has shown that Med1 is a low molecular weight polysaccharide (34.8 kDa) with low PI. The 2D-NMR linkage analysis suggests a diverse array of glycosidic bonds within the exopolysaccharide structure. The functional properties of the EPS were evaluated for food industry applications, specifically for antioxidant (DPPH, FRAP an H2O2). Extracted Med1 EPS revealed significant emulsification activity against different food grade vegetative oils (Coconut oil, Corn oil, Canola oil, Avocado oil, Sunflower oil, Olive oil, and Sesame oil). The highest 33.9% flocculation activity was observed with 60 mg L−1 EPS concentration. It showed water-holding (WHC) of 107.6% and oil-holding (OHC) capacity of 110.8%. The functional EPS produced by Pseudomonas alcaligenes Med1 from Central Andean Chilean hot spring of central Chile can be a useful additive for the food-processing industry.

Mountains host significantly more data deficient and threatened bat species than lowlands

AbstractMountains harbour one third of the world’s biodiversity and much of it is under increasing anthropogenic pressure. Yet, global assessments of the occurrence, and threat status of most mountain taxa, especially elusive ones are lacking, thereby hindering conservation and research prioritisation. In this study, we synthesise the distribution and conservation status of bats, a species rich taxon on mountains. By using data on geographical and elevational distribution ranges from the International Union for Conservation of Nature (IUCN), we examined bat species richness on mountains, species that predominantly occur in mountains (‘mountain dwelling species’), and those restricted to upper montane and alpine regions within mountains (‘highland dwelling species’). We also used published trait datasets to investigate the traits that are associated with mountain dwelling in bats. Globally, we identified 148 mountain dwelling and 46 highland dwelling bat species. Bat diversity is highest in the Northern Andes and Guiana Highlands. The mountain dwelling nature of bat species was found to be significantly associated with biogeographic realm. Importantly, our results show that mountain dwelling species are proportionately more data deficient than species that predominantly occur in lowlands. Additionally, highland dwelling species are proportionately more threatened than lowland species. Our results highlight a significant dearth of knowledge on mountain dwelling bat species. We conclude that more research is needed for bats specialised on mountain ecosystems. Our results draw attention towards improving the knowledge and protection of bat species that occur predominantly at high elevations across the world.

Prioritization of important plant areas for conservation of frailejones (Espeletiinae, Asteraceae) in the Northern Andes

AbstractThe tropical Andes region harbors areas that are highly significant for biodiversity at both global and local scales. However, despite the severe conservation threats that this region has to confront, conservation initiatives are limited, by funding and because of the need for more information to decide which areas are priorities for conservation. Identifying Important Plant Areas (IPAs) offers a valuable methodology for establishing conservation priorities, a particularly complex task in a mega-biodiverse region such as the northern Andean tropics. Due to its iconic recognition and conservation value, this study focused on the Espeletiinae subtribe (Asteraceae) as a model group; hence, the distribution data for 138 species was compiled from 5560 georeferenced records. Using the IPA methodology, we divided the study area, this is, the distribution area of the subtribe in the Andean tropics, into 220 Units of Analysis (UA) represented by 10 × 10 km plots. Refined species’ distribution areas, incorporating richness, threatened species, and ecosystem-based richness distributions, were analyzed using newly generated maps to evaluate the conservation value of each UA. Our analysis identified 176 UAs with some level of relevance using sub-criterion cA1 (with 59 species) and 51 UAs using sub-criterion cB (with 76 species). Integrating both criteria, we classified 11 UAs as high-priority, 62 as medium-priority, and 147 as low-priority, highlighting the IPAs that require focused conservation efforts. Two identified high-priority IPAs are located in Venezuela and nine in Colombia, predominantly associated with the Eastern Cordillera. These areas concentrate between 7 and 12 species. They are mainly linked to the páramo complexes of Colombia and the Sierra Nevada in Venezuela, primarily within Cool Temperate Moist Grassland ecosystems on mountains. Our results provide a spatial planning procedure and analytical tool for decision-makers to guide conservation management and actions across northern Andes.

Garnet clinopyroxenite formation via amphibole-dehydration in continental arcs: Evidence from Fe isotopes

Lower-crustal garnet clinopyroxenite (sometimes termed “arclogite”) fractionation in thick-crustal (>35 km) arc settings presents a compelling model to explain Fe-depletion trends, high oxygen fugacity, and evidence of recent delamination observed in many continental arcs. However, the origin of the garnet clinopyroxenites via igneous or metamorphic processes remains unclear. Due to the preferential incorporation of light Fe isotopes in garnet relative to clinopyroxene or amphibole, Fe isotopes are ideally suited for studying the effects of garnet fractionation on magmatic systems. Here, we present whole-rock and mineral Fe isotope data from a suite of lower to mid/upper-crustal Andean xenoliths from Mercaderes, Colombia. This data is combined with petrography, major and trace element mineral and whole-rock chemistry, geothermobarometry, and thermodynamic modeling to explore the xenoliths' petrogenesis and the Northern Andes' crustal structure. Whole-rock samples display a narrow range of Fe isotope compositions (δ56Fe = –0.02 to +0.11 ‰), which do not correlate with lithology, chemistry, or pressure-temperature conditions. This result is inconsistent with previous studies predicting the existence of an isotopically light Fe reservoir in the garnet-rich lower Andean crust. Through thermodynamic modeling, we show that the lack of isotopic fractionation in the Mercaderes xenoliths is more consistent with the suite representing a prograde metamorphic sequence, in which amphibole dehydration reactions drive metamorphism of mid/upper-crustal diorite protoliths. While our data do not preclude the presence of garnet clinopyroxenite cumulates at the base of the Andean crust, or that the delamination of such cumulates played an important role in the evolution of the Andes, they do indicate that not all garnet clinopyroxenites are cumulate in origin. Instead, the lower Andean crust represents an amalgamation of igneous and metamorphic rock, with metamorphism of mid-crustal lithologies and partial melting of mafic cumulate roots acting in tandem to drive densification and delamination of the lower crust in a self-feeding mechanism.

Turbulent Energy and Carbon Fluxes in an Andean Montane Forest—Energy Balance and Heat Storage

High mountain rainforests are vital in the global energy and carbon cycle. Understanding the exchange of energy and carbon plays an important role in reflecting responses to climate change. In this study, an eddy covariance (EC) measurement system installed in the high Andean Mountains of southern Ecuador was used. As EC measurements are affected by heterogeneous topography and the vegetation height, the main objective was to estimate the effect of the sloped terrain and the forest on the turbulent energy and carbon fluxes considering the energy balance closure (EBC) and the heat storage. The results showed that the performance of the EBC was generally good and estimated it to be 79.5%. This could be improved when the heat storage effect was considered. Based on the variability of the residuals in the diel, modifications in the imbalances were highlighted. Particularly, during daytime, the residuals were largest (56.9 W/m2 on average), with a clear overestimation. At nighttime, mean imbalances were rather weak (6.5 W/m2) and mostly positive while strongest underestimations developed in the transition period to morning hours (down to −100 W/m2). With respect to the Monin–Obukhov stability parameter ((z − d)/L) and the friction velocity (u*), it was revealed that the largest overestimations evolved in weak unstable and very stable conditions associated with large u* values. In contrast, underestimation was related to very unstable conditions. The estimated carbon fluxes were independently modelled with a non-linear regression using a light-response relationship and reached a good performance value (R2 = 0.51). All fluxes were additionally examined in the annual course to estimate whether both the energy and carbon fluxes resembled the microclimatological conditions of the study site. This unique study demonstrated that EC measurements provide valuable insights into land-surface–atmosphere interactions and contribute to our understanding of energy and carbon exchanges. Moreover, the flux data provide an important basis to validate coupled atmosphere ecosystem models.

Morphological characterization of the hippocampus: a first database in Ecuador.

The hippocampal volume is a well-known biomarker to detect and diagnose neurological, psychiatric, and psychological diseases. However, other morphological descriptors are not analyzed. Furthermore, not available databases, or studies, were found with information related to the hippocampal morphology from Latin-American patients living in the Andean highlands. The hippocampus is manually segmented by two medical imaging specialists on normal brain magnetic resonance images. Then, its morphological qualitative and quantitative descriptors (volume, sphericity, roundness, diameter, volume-surface ratio, and aspect ratio) are computed via 3D digital level-set-based mathematical representation. Furthermore, other morphological descriptors and their possible correlation with the hippocampal volume is analyzed. We introduce a first database with the hippocampus' morphological characterization of 63 patients from Quito, Ecuador, male and female, aged between 18 and 95 years old. This study provides new research opportunities to neurologists, psychologists, and psychiatrists, to further understand the hippocampal morphology of Andean and Latin American patients.

Land-use and ceramics in the Andean highlands of Patagonia, Argentina

The aim of this paper is to study the use of ceramics of small-scale societies during the late Holocene in northern Patagonia. The technological investment model predicts that use-time and utility will determine the investment spent in ceramics. We explore how ceramics were used in short-term camps and aggregation sites during summer at high elevations, and residential camps during winter at lower elevations. To test the investment in ceramics we use four technological variables: temper size, average thickness, surface treatment and firing. Our results indicate that hunter-gatherers expected a short-term use in summer locations and therefore made a low investment in ceramics.

Handgrip strength as a predictor of 1‑year mortality after hip fracture surgery in the Colombian Andes Mountains.

The aim of this study was to determine the association between low HGS and 1-year mortality in a cohort of older patients over 60years old with fragility hip fractures who underwent surgery in the Colombian Andes Mountains. A total of 126 patients (median age 81years, women 77%) with a fragility hip fracture during 2019-2020 were admitted to a tertiary care hospital. HGS was measured using dynamometry upon admission, and data about sociodemographic, clinical and functional, laboratory, and surgical intervention variables were collected. They were followed up until discharge. Those who survived were contacted by telephone at one, three, and 12months. Bivariate, multivariate, and Kaplan-Meier analyses with survival curves were performed. The prevalence of low HGS in the cohort was 71.4%, and these patients were older, had poorer functional and cognitive status, higher comorbidity, higher surgical risk, time from admission to surgery > 72h, lower hemoglobin and albumin values, and greater intra-hospital mortality at one and three months (all p < 0.01). Mortality at one year in in patients with low HGS was 42.2% and 8.3% in those with normal HGS, with a statistically significant difference (p = 0.000). In the multivariate analysis, low HGS and dependent gait measured by Functional Ambulation Classification (FAC) were the factors affecting postoperative 1-year mortality in older adults with hip fractures. In this study of older people with fragility hip fractures, low HGS and dependent gait were independent predictive markers of 1-year mortality.

Isolation and characterization of Pantoea ananatis and P. agglomerans in quinoa: P. ananatis as a potential fungal biocontroller and plant growth promoter.

Chenopodium quinoa, globally recognized as quinoa, stands out as one of the cereals with the highest nutritional value native to the Americas. It is cultivated in the Andes Mountain range, and Colombia is no exception, with the Boyacá department emerging as a significant quinoa-producing region. The quinoa ecosystem harbors a rich array of microorganisms within its rhizosphere. In this current study, nitrogen-fixing and phosphate-solubilizing isolates AM-0261 (Pantoea ananatis) and AM-0263 (Pantoea agglomerans) were sourced from rhizospheric soil samples of quinoa. These isolates were subjected to biochemical characterization and identification through PCR analysis and Sanger sequencing targeting a partial sequence of the 16s region of the rRNA. To assess their potential as plant growth-promoting rhizobacteria (PGPR), taking into consideration that P. ananatis is an IAA producer, greenhouse-based bioassays were conducted using seedlings. Additionally, dual culture assays were employed to showcase their antagonistic capabilities against primary beneficial and phytopathogenic fungi associated with quinoa cultivation in the region. The results underscore the remarkable potential of P. ananatis as a PGPR and a biocontrol agent against quinoa's phytopathogenic fungi. This study represents the pioneering exploration of the interaction between these two bacterial strains with quinoa rhizosphere tissue. In addition, the isolate of P. annatis (AM-0261) stands out, which presents phosphate solubilization capacity, nitrogen fixation, antagonistic capacity, and IAA production, characteristics that make it a promising strain for its use for the management of diseases of fungal origin, and in the future, it could be useful in reducing the use of chemical fertilizers.

Speciation and evolution of growth form in Adesmia D. C. (Dalbergieae, Fabaceae): the relevance of Andean uplift and aridification.

The Andean uplift and the concomitant aridification drove the rapid diversification of several plant lineages that were able to colonize warmer and drier habitats at low elevations and wetter and colder habitats at high elevations. These transitions may be facilitated by shifts in plant strategies to cope with drought and cold, which in turn can trigger episodes of accelerated species diversification. Here, we used four nuclear DNA markers to infer phylogenetic relationships of 80 Adesmia species of annuals, perennial herbs, shrubs and small shrubs that occur in Chile and Argentina. We reconstructed ancestral states for area, climatic niche and growth form to explore how Andean uplift and aridification promoted Adesmia diversification. We also performed logistic and linear regression analyses between different components of growth form (life span, woodiness and plant height) and climate. Finally, we estimated speciation rates across the phylogeny. Our results suggest that the ancestor of Chilean Adesmia was a perennial herb that probably originated in the high Andes of northern and central Chile. The low elevations of Central Chile were colonized in the late Miocene, whereas the high latitudes of Patagonia and the hyperarid coastal Atacama Desert were colonized repeatedly since Pliocene by lineages with different growth forms. Multiple and bidirectional transitions between annual and perennial habits and between herbaceous and woody habits were detected. These shifts were not correlated with climate, suggesting that the different growth forms are alternative and successful strategies to survive unfavorable seasons of both desert and high Andes. Net diversification analysis indicated a constant rate of diversification, suggesting that the high species diversity of Adesmia that occur in Chile is due to a uniform speciation process rather than to accelerated episodes of speciation.

First record of &lt;i&gt;Abrothrix olivacea&lt;/i&gt; (Waterhouse, 1837) in Peru based on historical material from Tacna

Abrotrichini is the sigmodontine tribe with the fewest species in Peru, known only from two species: Abrothrix andina and Ab. jelskii, both distributed in the high Andean regions of Peru above 3000 m in altitude. A detailed review of the morphology of historical specimens collected in the Tacna department and identified as Akodon mollis was conducted. As a result, we found that the examined specimens corresponded to Abrothrix olivacea, a species previously known only from Chile and Argentina. This discovery represents the first record of this species in Peru, extending its distribution range 165 km north of its previous northernmost record in Quebrada Camarones, Arica-Parinacota, Chile. Furthermore, this finding significantly reduces the distribution range of Akodon mollis to the northwestern region of Peru. We also provide key craniodental characters to differentiate species of Abrothrix and Akodon in southwestern Peru and northern Chile. For Peru, this record increases the diversity of mammals to 588 species and rodents to 201 species. In the case of the Tacna department, mammalian diversity increases to 47 species. This work highlights the value of natural history museum collections in enhancing our understanding of species diversity.

Water mites of a high-altitude thermal spring in the Chilean Andes (Acari: Hydrachnidia), with the description of a new Thermacarus species (Acari: Hydrachnidia: Thermacaridae)

New data are presented of water mites from a thermal spring in the high Andes of Chile. Three species have been found, i.e. Thermacarus chilensis n. sp., Hydryphantes thermalis Cook and Wandesia chechoi Cook.

Diversity of Mycorrhizal Types Along Altitudinal Gradients in the Tropical Andes

ABSTRACTAimMycorrhizal fungi play key roles in the functioning of terrestrial ecosystems. The main types of mycorrhizal associations are arbuscular mycorrhizae, ectomycorrhizae, ericoid mycorrhizae and orchid mycorrhizae. Previous studies have shown that the abundance of plants with different types of mycorrhizal associations change gradually along latitudinal and altitudinal gradients driven by the effects of climate and soil nutrients. We aimed to understand how altitude and climatic and soil variables shape the distribution patterns of tropical plant mycorrhizal types and nitrogen‐fixing plants along altitudinal gradients in the Andes.LocationColombian Andean mountain range.Time PeriodPresent day.Major Taxa StudiedPlants (vascular and non‐vascular).MethodsWe used a herbarium plant records database and assigned mycorrhizal type to each plant species based on the available literature. Bioclimatic and soil variables were also compiled at a resolution of 10 km. We calculated the proportion of each mycorrhizal association type per grid cell and created a diversity index to explore their spatial distribution and association with abiotic factors based on LMs.ResultsThe diversity of mycorrhizal associations increased with altitude and peaked around 3000 m, in an ecotone belt known as the subpáramo recognised by the high abundance of Ericaceae species. Soil carbon stock and soil total nitrogen were also positively correlated with the diversity of mycorrhizal types. Moreover, the abundance of arbuscular mycorrhizal plants was highest at low elevations and increased with the proportion of nitrogen‐fixing plants per cell.Main ConclusionsOur results indicate that mycorrhizal associations gradually change along altitudinal gradients in the tropical Andes. Climatic factors and the interactions between climatic and edaphic factors have the greatest explanatory power to predict the distribution of types of mycorrhizal associations along the altitudinal gradient. Based on these results we expect that climate change could potentially alter the distribution of mycorrhizal types in tropical mountains with unknown consequences for ecosystem functions.

A A new species of Graffenrieda (Melastomataceae) from the northern Andes, Caquetá, Colombia, and a key for the Graffenrieda group with calyptrate flowers

Background and Aims: Graffenrieda is a Neotropical genus with more than 70 species, mainly distributed in the Guiana Shield and the Andes. This work describes a new species of Graffenrieda and provides a key to identify all species with calyptrate flowers in the genus.Methods: The description of this new species was made from collections deposited in the Colombian herbaria JBB and COAH. Measurements of vegetative parts and inflorescence were made from dried material, while floral structures and fruits were measured from fresh material preserved in alcohol. Their conservation status was assessed according to IUCN guidelines. A key for the recognition of all species of the genus with calyptrate flowers, including the new species and Centronia species to be transferred to Graffenrieda is also provided here, for which lists of species in Neotropical countries, collection databases, and literature on both genera were consulted.Key results: Graffenrieda cardenasii sp. nov. is endemic to the southern Cordillera Oriental of Colombia and is characterized by its indumentum of irregular lepidote trichomes on the vegetative parts, leaves with incomplete lateral anisophylly, leafy bracteoles as large as the flower buds, 5-merous flowers, calyptrate calyx and 2-locular ovary. It is categorized as Endangered in view of its endemicity and habitat specificity. A key is provided for 30 species of the genus Graffenrieda that share the character of calyptrate flowers.Conclusions: This species is named in honor of the Colombian botanist Dairon Cárdenas López, a great collector and connoisseur of the Colombian Amazonian flora. It is so far known only from the type localities. The key to the species with calyptrate flowers included in this article allows 43% of the species in the genus Graffenrieda to be recognized, including four Centronia species.

Two new species of the genus Quindina Roewer, 1914 (Opiliones: Nomoclastidae) from Colombia: phylogenetic relationships and notes on their nest architecture

ABSTRACT Quindina Roewer, 1914 is a nomoclastid genus with 11 described species behaviourally characterised by its remarkable nest-building behaviour. In this paper we describe two new Colombian species of the genus from the western range of the Northern Andes, based on genital morphology and external characters. In addition, we explore their phylogenetic relationships using a phenotypic matrix with 96 characters, three newly proposed, and 55 terminals including all described species of Quindina and a wide outgroup sample across the suborder Laniatores. Quindina sanantonio sp. n. (type locality: Valle del Cauca, Santiago de Cali, San Antonio Forest) can be diagnosed by having two olive-green patches behind the ocularium and on the lateral portion of areas II and III, connected on the posterior margin of area III. Quindina horologium sp. n. (type locality: Risaralda, Santuario, Planes de San Rafael) can be diagnosed by having an hourglass-shaped dorsal pattern, beginning as two emerald-green patches next to the ocularium and continuing to the posterior margin of area III. Both species build nests without walls on the underside of leaves (ie flattened nest type), a previously unknown nest architecture for the genus. The phylogenetic analysis confirmed the monophyly of Quindina. The two new species, herein described, were recovered as basally branching within the genus. The inferred ancestral state for the nest architecture was the flattened nest type. We provide an updated key for the Colombian species of the genus Quindina and an updated distribution map. http://www.zoobank.org/urn:lsid:zoobank.org:pub:4C811186-3FAC-4F65-81BD-A5720513551E.