Andes Research Articles

Assessment of phenotypic diversity of Ñuña, a local common bean (Phaseolus vulgaris L.) from the northern Andes in Peru

Assessment of phenotypic diversity of Ñuña, a local common bean (Phaseolus vulgaris L.) from the northern Andes in Peru

Breeding biology of the Andean cock-of-the-rock (Rupicola peruvianus)

ABSTRACT The Andean cock-of-the-rock (Rupicola peruvianus) belongs to the Neotropical family Cotingidae, inhabiting the Andean mountains from Venezuela to Bolivia. Despite being a recognised and iconic species, most breeding studies of this bird have focused on its display behaviour at communal ‘leks’ rather than its basic nesting biology. Here, we present novel data on incubation behaviour and detailed descriptions of nests, eggs, and nestling development, with the first photographic evidence of nestlings being fed with vertebrates. We found 38 cup-shaped nests located along rocky walls near rivers or creeks in Peru, Ecuador, and Colombia. Nests were placed on rocky indentations along rivers, creeks, and waterfalls. The mean clutch size was two eggs. Eggs were beige with brown/green spots mainly located towards the wider end. Eggs measured 46.7 ± 1.2 mm by 32.7 ± 0.3 mm and weighed 25.6 ± 0.9 g. The incubation and nestling period lasted 26.0 ± 1.3 and 40.0 ± 2 days, respectively. During the incubation period, the female was the only parent attending the nest, with an average daily nest attentiveness of 87.3 ± 6.6%. The nestlings grew at a logistic curve rate (K) of 0.135 ± 0.005 g and kept their body temperature constant at 39.3°C only after day 30 of development. Detailed natural history accounts of the nest locations are necessary to generate long-term monitoring and successful conservation strategies of Neotropical species, especially for large frugivorous birds such as R. peruvianus that have long nesting cycles, specific nesting locations and are highly sensitive to forest fragmentation.

Assessment of scenarios for intensifying pasture management and grazing in fragile micro-watersheds of high Andean mountains

In the Andean hillsides of Ecuador, indigenous populations use land mainly for grazing sheep and cattle. Animal response depends exclusively on the quality of forage and the soil’s physical and chemical conditions. The objective of this research was to evaluate two scenarios for intensifying pastures based on perennial ryegrass (Lolium perenne) and white clover (Trifolium repens), used at rest periods of 45- and 60 days in sites between 3,000-3,400 m a.s.l. used for grazing sheep and cows. These scenarios were compared with a natural grassland based on a plant community composed of Stipa ichu, Holcus lanatus, Rumex acetocella, and Paspalum sp., used in a traditional system with rest periods of 60-75 days in sites between 3,500-3,700 m a.s.l. in the Chimborazo River micro-watershed. Soil sampling was conducted at both sites to determine the soil fertility profile. Regarding the forage component, chemical composition, animal carrying capacity, milk production, and estimated enteric CH4 emissions were determined. In sheep serum, Ca, P, and Mg profiles, and the activity of AST, ALT, and FA enzymes were analyzed. The data were analyzed using ANOVA and Tukey 5% as a means comparison test. The results showed a better physicochemical property of the soil at the lower altitude. The intensification of pasture management and grazing through the utilization of rest periods of 45 days or less may represent a productive and low-emission option.

Niche packing, but not niche expansion, explains the co‐occurrence of hummingbirds‐visited plants

Tropical mountains often harbour high species richness. Yet the mechanisms behind such high richness remain poorly understood. One prominent hypothesis for high species richness is niche partitioning, which reduces competition and promotes coexistence. Here, we evaluate niche structure and specialisation of plant species based on the floral traits related to pollination interactions across an elevational gradient in the northern Andes. Niche structure can vary among sites, either expanding or contracting, or becoming more or less packed. We sampled eleven communities of hummingbird‐visited plants along an elevation gradient in the Ecuadorian Andes and measured a series of functional traits associated with hummingbird pollination. We used the traits of all co‐occurring species to calculate community weighted means, functional richness, and mean nearest neighbour distances and evaluated how they varied across elevation. Additionally, we measured specialisation based on plant–hummingbird interaction records to assess if packing is associated with narrower resource use or greater niche overlap. Species and functional richness were constant along the elevation gradient; however, niche packing was stronger at mid‐elevation. We found changes in network specialisation, where the least specialised communities were those with higher niche packing. These results suggest that traits related to pollination and plant reproduction help to explain species co‐occurrence and specialisation.

Topological insights into the diachrony of ancient road networks: Exploratory predictive modelling in the Andean highlands

Topological insights into the diachrony of ancient road networks: Exploratory predictive modelling in the Andean highlands

Sediment provenance signal of the Northern Andes during the Oligocene-Pliocene: Insights from the detrital record of the forearc and intra-arc basins, northwestern Colombian margin

Sediment provenance signal of the Northern Andes during the Oligocene-Pliocene: Insights from the detrital record of the forearc and intra-arc basins, northwestern Colombian margin

Future Climate Projections for Tacna, Peru: Assessing Changes in Temperature and Precipitation

The Tacna region, situated in southwestern Peru, is distinguished by its desert and Andean zones, resulting in significant climatic variability. However, changes in future precipitation and temperature patterns could significantly impact sectors such as agriculture, energy, and water resources. In this context, this research analyzes climate scenarios of precipitation, maximum temperature (Tmax), and minimum temperature (Tmin) in Tacna. For this purpose, Tacna was divided into four homogeneous regions (Coast, Low Highlands, High Andes, and Andean Plateau) to assess future changes using CMIP6 climate models for the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. A bias correction of these models was applied using the Quantile Delta Mapping method to improve accuracy. The validation results showed better performance for minimum temperature compared to maximum temperature and precipitation. Regarding the scenario results, by the end of the century, under the SSP5-8.5 scenario, Tmax could increase by up to +7 °C while Tmin could rise by up to +5 °C, particularly in the Andean Plateau. Precipitation is projected to decrease by up to 20% annually in higher elevations, albeit with considerable uncertainty; however, no significant changes are expected in seasonal patterns. This study underscores the importance of robust climate projections in formulating adaptation strategies for water resource management and infrastructure planning. The findings provide essential insights for decision-makers to address the challenges posed by climate change in vulnerable regions of southern Peru.

Study of the Physical–Chemical, Thermal, Structural, and Rheological Properties of Four High Andean Varieties of Germinated Chenopodium quinoa

Chenopodium quinoa, a high Andean grain with excellent nutritional value and complex molecular structure, presents significant challenges in the bioavailability of nutrients and the functionality of its components. Germination as a biotechnological strategy generated significant modifications in four varieties of quinoa. The ungerminated and germinated samples’ physical–chemical, thermal, structural, and rheological properties were determined. Results showed increases in protein bioavailability (14.13% in Black Collana Quinoa (BCQ) and 12.79% in Red Pasankalla Quinoa (RPQ)), phenolic compounds (30.81 mg Gallic Acid Equivalent/100 g in RPQ), flavonoids (108.53 mg Quercetin Equivalent/100 g in Yellow Marangani Quinoa (YMQ)), and antioxidant capacity (up to 241.43 μmol Trolox Equivalent/g in BCQ). Thermal analysis showed increases in gelatinization temperature (57.53 °C to 59.45 °C in RPQ) and a reduction in enthalpy (1.38 J/g to 0.67 J/g). Structural analysis showed similar functional groups, but variation in spectra intensity was related to starches and proteins. Rheological properties exhibited pseudoplastic behavior at 80 °C. Principal component analysis showed a clear difference between germinated and non-germinated samples. The germination process significantly modified quinoa, improving its nutritional and functional properties and generating new opportunities for its application in the development of biodegradable materials and functional foods.

Higher Proportion of High‐Energy Lightning Strokes in Global High‐Altitude Areas

AbstractBy examining proportions of high‐energy strokes from the World Wide Lightning Location Network (WWLLN) between 60°S and 60°N, and high‐radiance events from the Lightning Imaging Sensor (LIS) between 38°N and 38°S, along with the average energies of WWLLN strokes and LIS events with specific thresholds, we discovered significantly higher proportions of high‐energy lightning strokes and greater average stroke energies over high‐altitude terrains, a phenomenon not previously reported. These highlands include the Tibetan Plateau, Mongolian Plateau, Iranian and Anatolian Plateaus, South African Plateau, mountain regions in western North America, and Andes Mountains. In terms of both proportion and average energy, high‐energy WWLLN strokes show a stronger correlation with highlands than high‐energy LIS events. Considering the different observation modes of WWLLN and LIS, this may suggest a stronger connection between highlands and high‐energy lightning strokes occurring beneath and in the lower parts of thunderstorms.

Integrative taxonomic study of Coccoloba gracilis (Polygonaceae) and C. ruiziana from Amotape–Huancabamba neotropical biodiversity hotspot

Abstract Accurate species delimitation is necessary to estimate species diversity. However, species delimitation remains challenging in the poorly studied Coccoloba genus in the northern Andes. Coccoloba gracilis and C. ruiziana are endemic related species inhabiting dry seasonal tropical forest of the Amotape–Huancabamba zone in Ecuador and Peru. The identity of C. ruiziana is widely recognized. However, some information about C. gracilis is missing and its identity has not been thoroughly checked by previous authors. We used morphological, phylogenetic, and ecological data in a robust methodological approach to investigate species boundaries. We studied 251 specimens from 17 herbaria, representing the entire distribution range of this species. Morphometric analysis suggested significant differentiation of multiple traits. Our phylogeny recovered Coccoloba gracilis related to C. ruiziana but with low statistical support. The results of ecological niche models showed a low levels of niche overlap between them. Our results support the recognition of two distinct species. Coccoloba gracilis Kunth emend. Arnelas mut. char., distributed in semi-deciduous, montane low forest and first rediscovered in Ecuador, and C. ruiziana, distributed at lower altitudes in lowland, dry seasonal tropical forest. Descriptions, photographs, and nomenclature notes are provided. One second-step lectotypification and one epitype for C. gracilis are provided.

Integration of InSAR coherence and SAR backscatter increases accuracy of LULC mapping in tropical high-mountain ecosystems

Páramos, neotropical high-mountain biomes of the northern Andes, are increasingly threatened by human land use and climate change. Accurate land use/land cover (LULC) mapping is critical for monitoring these pressures. However, persistent cloud cover poses substantial challenges for optical satellite imagery. This study leverages multitemporal Interferometry SAR (InSAR) coherence and dual polarimetric backscatter intensity to improve LULC mapping accuracy in páramos ecosystems. Using a 1-year Sentinel-1 time series from January to December 2019, 17 LULC classes were mapped across 17,000 hectares. Results demonstrate that integrating backscatter and coherence increased F1-Score and overall accuracy by 9% and 11%, respectively, compared to backscatter alone. This emphasizes the critical role of multitemporal SAR for LULC mapping in cloud-prone regions. Additionally, this study underscores the utility of cloud-based platforms for efficient SAR data processing, offering a scalable approach for mapping high-mountain ecosystems worldwide, especially in inaccessible and heavy precipitation regions.

Proposal to list the Peruvian tuco-tuco (Ctenomys peruanus, Ctenomyidae, Rodentia) as a critically endangered species

Abstract. Medina CE, Medina YK, Bocardo EF. 2024. Proposal to list the Peruvian tuco-tuco (Ctenomys peruanus, Ctenomyidae, Rodentia) as a critically endangered species. Biodiversitas 25: 5005-5011. The Peruvian tuco-tuco, Ctenomys peruanus Sanborn and Pearson 1947, is a subterranean rodent endemic to High Andes of southern Peru. This rodent is historically known by four record localities dating back to the 1950s, and a fifth locality in 2011, all based on specimens housed in natural history museums, is now facing a critical situation. Recent surveys in 17 localities in Arequipa, Moquegua, Tacna, and Puno regions revealed the local extinction of C. peruanus at previously recorded sites while identifying two new localities; however, currently, the species only lives in one locality (Callacami, Puno). This remaining population of fewer than 50 mature individuals is under intense hunting pressure for human consumption and traditional medicinal practices, and it is experiencing a continuous loss of the extension and quality of its habitat due to overgrazing and agricultural expansion. Our research is the first effort to fill a 72-year gap with no field data for C. peruanus. Therefore, we propose to categorize C. peruanus as a Critically Endangered species (CR) according to the criteria established by the International Union for Conservation of Nature's Red List of Threatened Species. The authorities and academic community are urged to join efforts to curb the aforementioned anthropogenic threats and devise and implement management and conservation plans for C. peruanus in Peru.

Andean lakes: endangered by natural and anthropogenic threats

ABSTRACT The Andes mountains extend north–south in a latitudinal gradient of 8500 km. Because of the great climatic variety and the peculiar north–south orographic distribution, lakes are highly diverse, including different lake origins and contrasting morphometries. We reviewed >700 ecological studies on Andean lakes to identify the main threats to these freshwater systems. The most important threats are UV radiation, changes in water balance, and eutrophication, all 3 interacting with climate change, alien species introductions, and mining. UV radiation is an important factor in Andean lakes not only because of the altitude but also because many lakes are included in the Antarctic ozone hole. The introduction of alien species, particularly exotic salmonids, also had detrimental effects, affecting native fish populations and behaviour and endemic species by disrupting the indigenous food web. Eutrophication and browning caused by human activities, including land use interacting with climate change, are increasing in Andean lakes, causing a decrease in water quality. Finally, mining can cause water contamination (both groundwater and surface water) by chemicals emitted from mining processes, thus producing a loss of biodiversity. Although an important number of Andean lakes have been declared as Ramsar sites because of their uniqueness and their extreme conditions, they are subject to significant human impacts. Here, for the first time, we identify these impacts all along the Andes; however, further studies at different scales are mandatory if we hope to understand, conserve, and manage Andean lakes.

The Process‐Oriented Understanding on the Reduced Double‐ITCZ Bias in the High‐Resolution CESM1

AbstractThe double‐Intertropical Convergence Zone (ITCZ) bias is a common model bias, which has puzzled the climate model community for several decades. Here, by comparing a high‐ and low‐resolution state‐of‐the‐art model CESM1, it is found that the double‐ITCZ bias is largely reduced in the high‐resolution CESM1. The key reason is the realistic colder sea surface temperature (SST) over the southeast Pacific (SEP) in the high‐resolution model. This realistic SEP SST is mainly due to a spuriously deeper mixed layer with a more realistic wind, as the sensitivity of mixed layer depth to wind is overestimated in both versions of CESM1. The better representation of terrain, such as Andes Mountains, elevates warm advection from inland to the coastal region, which maintains the inversion structure favorable for low cloud. The resultant increased coastal cloud in the high‐resolution CESM1 causes the colder coastal SST, thus improving the wind and deepening the mixed layer.

First record of the millipede family Haplodesmidae (Diplopoda: Polydesmida) from Colombia: two new species of Inodesmus Cook, 1896 from the Northern Andes

The millipede family Haplodesmidae is reported from Colombia for the first time, represented by Inodesmus mesibovi sp. nov. and Inodesmus miconiae sp. nov. Their presence in primary and secondary oak forests suggests their native origin in Colombia. This discovery represents the first record of the genus Inodesmus Cook, 1896 in South America, with potential implications of further records of the genus and family from the continent. We also present the first record of teratologies in haplodesmid millipedes.

A systematic review of ecosystem services in the Rabanal páramo (Colombia)

Abstract Colombian páramos, strategic ecosystems of the northern Andes, provide a broad range of ecosystem services such as carbon sequestration, water regulation, and soil protection. The department of Boyacá in Colombia contains the largest area of páramo ecosystems, with the Rabanal páramo serving as the primary water source for the capital city of Tunja. Despite scientific studies on the diversity of flora and fauna, páramos remain among the least studied ecosystems regarding their services. No study has yet addressed a detailed systematic review assessing the range of ecosystem services in the Rabanal páramo. We systematically reviewed 162 documents published between 1992 and 2022 to assess the progress of ecosystem services knowledge, identify biases, and define research priorities. Most of the studies (60%) focused on regulating services, followed by cultural services (24%) and provisioning services (16%). In the category of regulating services, biodiversity maintenance is the most studied service with 60 studies (37%), followed by vegetation cover with 22 studies (14%). In provisioning services, fresh water has the most studies 18 (11%), while environmental education, with 16 studies (10%), is the cultural service with the most publications. Likewise, we identified 21 different research methods in the documents. The most employed was environmental assessment (23%), followed by stakeholder engagement and environmental planning (10%) and inventory (7%). We conclude that there is a significant research gap in prioritizing the understanding of cultural services and the impacts of conservation initiatives on páramo communities. This unique ecosystem, which is not only a source of livelihood for local farmers but also deeply connected with their cultural identity and heritage, underscores the need to address these gaps to sustain the Rabanal páramo ecosystem.

Late Miocene – Pliocene eastward magmatic arc migration record in the Northern Andes at 5°N latitude, west-central Colombia

ABSTRACT Volcanic stratigraphy provides major insights to understand the spatial and temporal relationships between volcanic products and eruptive and post-eruptive processes. In the Andean chain, the Neogene to modern magmatic arc front has shown major changes in their spatial and compositional characteristics, which have been commonly related to significant modifications in the plate configuration. In the northern segment of the Colombian Andes, at 5°N latitude, a series of Upper Miocene-Pliocene volcanic and volcaniclastic units record the Neogene tectono-magmatic evolution associated with the formation of the Andean orogen. Stratigraphic observations allow recognising primary, secondary, and non-volcanic products that document intra- and inter-eruptive episodes characterised by Plinian eruption styles associated with the construction of volcanic edifices, followed by inter- and post-eruptive periods with significant fluvial dominated sedimentation. This indicates the reworking of volcanic products associated with the destruction and the collapse phase of volcanic edifices. New geochronological data (U-Pb and K-Ar) and several published ages suggest the existence of a continuous arc magmatism from the Miocene until the present, with major changes in its spatial position of the frontal arc: during the Late Miocene (~6 Ma), was exposed in the west between the Middle Cauca Valley to the Central Cordillera, while during the Pliocene (~4 Ma), it was located exclusively in the Central Cordillera. This configuration was the result of the inland magmatic arc migration associated with the subduction dynamics of the Nazca plate (Malpelo microplate) under the South American margin that also promoted a late phase of exhumation of the Cordillera.

Lessons Learned From Direct Seeding to Restore Degraded Mountains in Cauca, Colombia

ABSTRACTDirect seeding is a technique frequently used to restore degraded lands worldwide. Direct seeding is attractive to restore degraded lands mainly because of its low cost compared to planting seedlings. However, this technique has been poorly studied in tropical mountains. Here, we investigated the outcomes of direct seeding at four degraded sites in the Andean mountains of Cauca, Colombia. We used 45 native tree species, most of them commonly used in restoration projects in the Andean region of Colombia. After 150 days of sowing, we evaluated seedling emergence, survival and establishment costs. Performance of direct seeding was markedly different across sites. Most species had low seedling emergence, with Guayaba (Psidium guajava) and Matachande (Bocconia frutescens) showing the highest emergence. Species with large seeds showed higher emergence compared with medium and small seeds. Seedling density was considerably variable among sites, ranging from 496 to 5550 ind. ha−1. Our results evidence the need for long‐term monitoring at mountain restoration sites and that restoring tropical degraded mountains using direct seeding is a challenge that can be complemented with native tree planting. Further research is required to explore the advantages and disadvantages of direct seeding in mountain terrain.

The influence of the forest corridors to the north of the Andes on the diversification of the bright-rumped Attila, Attila spadiceus (Passeriformes, Tyrannidae), during the climatic oscillations of the middle Pleistocene.

This study aims to enhance our understanding of the temporal and spatial processes scales governing the evolutionary diversification of Neotropical birds with Trans- and Cis-Andean populations of the species Attila spadiceus from South and Central America. Through a multilocus analysis of the mitochondrial (CytB and ND2) and nuclear genes (I7BF, I5BF, and G3PDH) of 41 samples representing six subspecies, we describe the existing molecular lineages of A. spadiceus, and estimate their demographic dynamics. We used Ecological Niche Modeling (ENM) with six different algorithms to predict the potential distribution of A. spadiceus in both present-day and past scenarios, examining the overlap climatic niche between Cis- and Trans-Andean lineages. The analysis confirms a relatively recent divergence of the Trans- and Cis-Andean lineages, at approximately 0.25 million years ago (Ma). The niche modeling supports the existence of a dynamic scenario of the expansion and retraction of forest corridors in northwestern South America during the last glaciation. This suggests that the earlier orogenesis of the Andes was not a primary determinant of this dichotomy. Additionally, the analysis of population dynamics indicated a trend of increasing population size starting at 0.05 Ma for both lineages. Our findings highlight the significance of Pleistocene Forest corridors north of the Andes as the key factor maintaining communication before the separation of the lineages, likely associated with the retraction of this forest. We highlight the absence of any significant differentiation between the disjunct Amazonian and Atlantic Forest populations, at both part of the Cis-Andean lineage. The phylogeographic profile of A. spadiceus diverges from the patterns observed in other Neotropical birds, which emphasizes the need for further research on the role of the forest corridors of the northern Andes as drivers of diversification, to provide comprehensive insights into the processes that led to the formation of the region's present-day avian diversity.

Miocene Construction of the High Andes Recorded by Exhumation of the Frontal Cordillera, La Ramada Massif of Western Argentina (32°S)

AbstractThe Frontal Cordillera is a first‐order geologic feature of the southern central Andes, hosting the highest hinterland topography above the modern Pampean flat‐slab segment. The timing of Frontal Cordillera exhumation is important for testing models of Andean tectonics, yet large latitudinal gaps exist between structural and thermochronological constraints for the region. We conducted a thermochronometric study using a 4.4 km age‐elevation transect along the northeast ridge of Cerro Mercedario, the highest peak in the La Ramada massif at ∼32°S. Zircon (U‐Th)/He dates indicate partial resetting, supporting a limited magnitude of exhumation in even the most extreme Andean topography. Single grain apatite (U‐Th‐Sm)/He dates range from 8.5 ± 0.9 to 35.8 ± 3.6 Ma, with median dates of ∼10.5 to ∼15.7 Ma with increasing elevation. Integrated with geologic mapping and thermal history modeling, these data suggest Early to Middle Miocene exhumation along the Santa Cruz and Espinacito faults concomitant with uplift of the La Ramada massif. New apatite helium data from the Cordillera del Tigre segment of the Frontal Cordillera are partially reset and preferred modeling interpretations suggest exhumation ca. 11–9 Ma, coeval with shortening in the eastward adjacent Precordillera. These data add to accumulating regional evidence for out‐of‐sequence deformation during the Miocene, consistent with internal (hinterland) growth of a subcritical orogenic wedge contemporaneous with surface uplift and crustal thickening in the south‐central Andes.