Search Results (26)

Protected areas play a key role in containing and protecting most of the endemic biodiversity of megadiverse places, underscoring their importance as custodians of biological richness. Colombia, one of the most species-rich countries, also has one of the highest rates of deforestation globally. The Colombian National Natural Parks (NNPs) system is one of the mechanisms for protecting natural landscape ecosystems and biota. Based on the role of butterflies as bioindicators in biodiversity mapping, we compiled records of endemic butterfly species from entomological collections and the literature to assess the importance of protected areas in endemic species conservation. The NNPs harbor records of 127 endemic species, representing 65% of the 196 endemic butterfly species recorded in Colombia. Most of these endemic species, 93 species, have been recorded in only one NNP, here defined as “unique” species. These species are mainly distributed along the Andes Cordillera. Among all the NNPs, Sierra Nevada de Santa Marta holds the highest number of both total and unique endemic species. Extrapolating this pattern to the broader Andean Biota supports the idea that protected areas play a key role in containing and protecting much of Northern South American endemic biodiversity, underscoring their importance as custodians of biological richness. Full article

The understanding of species distribution in Peru is limited, in part due to cartographic representations that traditionally use political rather than biogeographical boundaries. The objective of this study was to determine the distribution of Arecaceae species in the department of Amazonas by representing them in biogeographical regions. To this end, geographic information systems and global databases were used to map and analyze the species in four categories: Ecosystems Map, Ecoregions Map, Peru Climate Classification Map, and Protected Natural Areas Map. Subsequently, diversity metrics were estimated, revealing high diversity in Amazonas, with 22 genera and 90 species of Arecaceae representing 51.16% and 41.28% of the records in Peru, respectively. In addition, predominant genera and species were identified, and diversity was evaluated in biogeographic units. Of a total of 336,029 records, 45 genera were found, with Geonoma and Bactris being the most representative, and of the 218 species found in total, the records that stood out the most varied according to biogeographical regions. For each Biogeographic unit by category, different responses were obtained, for example, for Index Margalef, between 0.000 (low in Agricultural Area), 7.2489 (medium in Eastern Cordillera Real Montane Forests), and 13.2636 (high in Non-protected Areas). Similarly, for the Shannon–Wiener diversity index ($\overline{H}$), where values were obtained between 0.000 (low in Jalca (Andean High Grasslands), (medium in Reserved Zonez) and 3.7054 (high in Non-protected Areas). The results suggest high under-recording, evidencing gaps in knowledge and information, as analyses based on detailed studies of diversity in specific biogeographic categories in these other families, as well as future research to determine, for example, genomes and Hill numbers, will be carried out. The conclusions highlight the high correlation between the diversity metrics analyzed, confirm the theoretical validity, and allow us to recommend species richness and the Margalef Index as useful and relevant metrics due to their applicability and ease of interpretation. This study offers key information for decision makers in policies for the conservation of Arecaceae diversity and motivates us to project research of this type in other families in Peru. Full article

The structural evolution of Andean-type orogens is strongly influenced by the geometry of the subducting slab. This study focuses on the flat-slab subduction of the Nazca Ridge and its effects on the South American Plate. The process of flat slab subduction impacts the stress distribution within the overriding plate and increases plate coupling and seismic energy release. Using the finite element method (FEM), we analyse interseismic and coseismic deformation along a 1000 km transect parallel to the ridge. We examine stress distribution, uplift patterns, and the impact of megathrust activity on deformation. To better define the crust’s properties for the model, we developed a new thermal model of the Nazca Ridge subduction zone, reconstructing the thermal structure of the overriding plate. The results show concentrated stress at the upper part of the locked plate interface, extending into the Coastal and Western Cordilleras, with deeper stress zones correlating with seismicity. Uplift patterns align with long-term rates of 0.7–1 mm/yr. Cooling from flat-slab subduction strengthens the overriding plate, allowing far-field stress transmission and deformation. These findings provide insights into the tectonic processes driving stress accumulation, seismicity, and uplift along the Peruvian margin. Full article

Cumulus parameterization schemes model the subgrid-scale effects of moist convection, affecting the prognosis of cloud formation, rainfall, energy levels reaching the surface, and air quality. Working with a spatial resolution of 1 km, we studied the influence of cumulus parameterization schemes coded in the Weather Research and Forecasting with Chemistry Version 3.2 (WRF-Chem 3.2) for modeling in an Andean city in Southern Ecuador (Cuenca, 2500 masl), during September 2014. To assess performance, we used meteorological records from the urban area and stations located mainly over the Cordillera, with heights above 3000 masl, and air quality records from the urban area. Firstly, we did not use any cumulus parameterization (0 No Cumulus). Then, we considered four schemes: 1 Kain–Fritsch, 2 Betts–Miller–Janjic, 3 Grell–Devenyi, and 4 Grell-3 Ensemble. On average, the 0 No Cumulus option was better for modeling meteorological variables over the urban area, capturing 66.5% of records and being the best for precipitation (77.8%). However, 1 Kain–Fritsch was better for temperature (78.7%), and 3 Grell–Devenyi was better for wind speed (77.0%) and wind direction (37.9%). All the options provided acceptable and comparable performances for modeling short-term and long-term air quality variables. The results suggested that using no cumulus scheme could be beneficial for holistically modeling meteorological and air quality variables in the urban area. However, all the options, including deactivating the cumulus scheme, overestimated the total amount of precipitation over the Cordillera, implying that its modeling needs to be improved, particularly for studies on water supply and hydrological management. All the options also overestimated the solar radiation levels at the surface. New WRF-Chem versions and microphysics parameterization, the other component directly related to cloud and rainfall processes, must be assessed. In the future, a more refined inner domain, or an inner domain that combines a higher resolution (less than 1 km) over the Cordillera, with 1 km cells over the urban area, can be assessed. Full article

The high mountain forests on Earth are characterized by sharp environmental heterogeneity, high species endemism, and unique phenotypic adaptations. Yet, global warming is jeopardizing this ecosystem as no other as some forests may have nowhere to go beyond the mountain’s summits. One of the most human-endangered high-elevation ecosystems is the Polylepis forest. Despite its vulnerability, forecasting climate reactions in this distinctive high mountain forest type remains a formidable challenge. Therefore, in this study, we modeled climate change responses of high-elevation allopatric Polylepis sericea and P. quadrijuga (Rosaceae) in the northern Andes. The analysis took into account VIF-prioritized bioclimatic variables for near-to-present and future (2081–2100 MPI-ESM1-2-HR) conditions. Model selection was carried out following the AUC scores of 12 MaxEnt and six machine learning algorithms. Predictive power reached 0.97 for MaxEnt’s model fc.H_rm.1 (H-1). Results indicate a moderate vulnerability of P. sericea, with a 29% loss of area in the trailing edge, due to climate change for the period 2081–2100. On the other hand, P. quadrijuga is likely to experience even larger distribution losses, up to 99%, for the same period. The findings of this study suggest that P. quadrijuga, as compared to P. sericea, exhibits a restricted ability to maintain the corresponding habitat requirements in the face of climatic change. Higher niche specialization of P. quadrijuga in the environmentally heterogeneous Eastern Cordillera contrasts with the more generalist nature of P. sericea in the topographically less complex Central Cordillera. In addition to climate change, this trend may be exacerbated by the detrimental effects of agriculture, mining, and an expanding rural population, which represent significant human-driven pressures yet to be modeled in the northern Andean highlands. Yet, based on previous studies, the historical population dynamics during the past glacial cycles suggests that range shifts could play a more significant role at deeper time scales than previously forecasted in the species’ reaction to climate change. Additionally, Polylepis forests may be able to endure at the current locations via local adaptation and plasticity, major drivers of the phenotypic variation in long-lived trees, counteracting the vulnerability scenario under a niche conservatism hypothesis. Ultimately, the modeling procedure employed in this study provides insights into the potential effects of climate change on Polylepis forests 70 years from now. Oncoming studies may consider alternative responses inherent to the gene pool of the species and the interaction with edaphic and biotic agents. We advocate for the application of comparable estimations in other high-elevation tree communities found at the tree line. Full article

The aseismic Nazca Ridge produces localized flat-slab subduction beneath the South American margin at latitudes 10° to 15° S. The geological evolution and the spatio-temporal pattern of deformation of the upper plate have been strongly influenced by the presence of the flat slab. In this study, we investigated the lithospheric thermal structure of this region by elaborating a 2D geothermal model along a section across the top of the Nazca Ridge, the Peru–Chile trench, the Andean Cordillera, and the Amazonian Basin, for a total length of 1000 km. For the sake of modelling, the crust of the overriding plate was subdivided into two parts, i.e., a sedimentary cover (including the entire lithostratigraphic sequence) and a crystalline basement. Applying an analytical methodology, we calculated geotherms and isotherms by setting (i) thickness, (ii) density, (iii) heat production, and (iv) thermal conductivity for each geological unit and considering (v) heat flux at the Moho, (vi) frictional heating produced by faults, and (vii) plate convergence rate. The resulting model could make a significant advance in our understanding of how flat slab geometry associated with the Nazca Ridge subduction affects the thermal structure and hence the tectonic evolution of the region. Full article

Landslide occurrence in Colombia is very frequent due to its geographical location in the Andean mountain range, with a very pronounced orography, a significant geological complexity and an outstanding climatic variability. More specifically, the study area around the Bogotá-Villavicencio road in the central sector of the Eastern Cordillera is one of the regions with the highest concentration of phenomena, which makes its study a priority. An inventory and detailed analysis of 2506 landslides has been carried out, in which five basic typologies have been differentiated: avalanches, debris flows, slides, earth flows and creeping areas. Debris avalanches and debris flows occur mainly in metamorphic materials (phyllites, schists and quartz-sandstones), areas with sparse vegetation, steep slopes and lower sections of hillslopes; meanwhile, slides, earth flows and creep occur in Cretaceous lutites, crop/grass lands, medium and low slopes and lower-middle sections of the hillslopes. Based on this analysis, landslide susceptibility models have been made for the different typologies and with different methods (matrix, discriminant analysis, random forest and neural networks) and input factors. The results are generally quite good, with average AUC-ROC values above 0.7–0.8, and the machine learning methods are the most appropriate, especially random forest, with a selected number of factors (between 6 and 8). The degree of fit (DF) usually shows relative errors lower than 5% and success higher than 90%. Finally, an integrated landslide susceptibility map (LSM) has been made for shallower and deeper types of movements. All the LSM show a clear zonation as a consequence of the geological control of the susceptibility. Full article

This study examined the changes in tussock grass greenness over 18 years (2001–2018) using NDVI data from 10 key areas of the Páramo ecosystem in the Ecuadorian Andes. In addition, the study investigated the influence of hydrometeorological variables (precipitation, soil temperature, and water availability) and climatic indices (AAO, MEI, MJO, NAO, PDO, El Niño 1 + 2, 3, 3.4, and 4) on greenness dynamics. The spatial and temporal variations of NDVI were studied, applying several analysis and indicators, such as: the standard deviation, z-score anomalies, Sen slope, Mann–Kendall test, and time integrated-NDVI (TI-NDVI). Linear and multilinear correlations were used to evaluate the influence of hydrometeorological variables and climatic indices on the greenness of tussock. The findings of the study show that Páramo, located in the Inter-Andean valley above 2° S, is the most productive, followed by those located in the Royal Range (eastern cordillera). The anomalies and trends of NDVI on the Royal Range tended to be greening over time. NDVI showed a moderate multilinear correlation with precipitation and soil temperature, and a strong response to water availability. Finally, NDVI was weakly linearly related to the climatic indices, the most representative being the MJO, and slightly related to ENSO events. Understanding the regional and global-scale variables that control tussock grasses’ phenology will help to determine how present and future climate changes will impact this ecosystem. Full article

To better understand the origin of the Andean iron oxide-apatite (IOA) deposits, we conducted a study on the geology and magnetite geochemistry of the Mariela IOA deposit in the Peruvian Iron Belt, central Andes. The Mariela deposit is hosted by gabbroic and dioritic intrusions. The major high-grade massive ores are primarily composed of magnetite and contain variable amounts of apatite and actinolite. Based on textural and geochemical characteristics, three different types of magnetite are recognized: Type I magnetite occurs in the massive magnetite ore, subclassified as inclusion-rich (I-a), inclusion-free (I-b), and mosaic (I-c); Type II magnetite is associated with abundant actinolite and titanite; and Type III magnetite is disseminated in altered host rocks. However, the magnetite geochemistry data for the Mariela deposit plot shows different genetic areas in [Ti + V] vs. [Al + Mn], Ti vs. V, and Fe vs. V/Ti discrimination diagrams, indicating a paradox of magmatic and hydrothermal origins. Our interpretation is as follows: Type I-a magnetite had an initial magmatic or high-temperature magmatic-hydrothermal origin, with slight modifications during transportation and subsequent hydrothermal precipitation (Types I-b and I-c). Type II magnetite is formed from hydrothermal fluid due to the presence of abundant actinolite. Disseminated magnetite (Type III) and veinlet-type magnetite formed after fluid replacement of the host rock. We stress that elemental discrimination diagrams should be combined with field studies and textural observations to provide a reasonable geological interpretation. A clear cooling trend is evident among the three subtypes of Type I magnetite (I-a, I-b, and I-c), as well as Type II and Type III magnetite, with average formative temperatures of 737 °C, 707 °C, 666 °C, 566 °C, and 493 °C, respectively. The microanalytical data on magnetite presented here support the magmatic-hydrothermal flotation model to explain the origin of IOA deposits in the Coastal Cordillera of Southern Peru. Full article

In this work, we apply multi-temporal 1D-magnetotelluric (MT) surveys to estimate the space–time variations of the apparent resistivity ${\rho }_a$ and correlate these changes with seismic activity in the central part of Colombia (South America). We use the time series of the Earth’s natural electric and magnetic fields registered at two MT stations of the National University of Colombia Seismological Network (RSUNAL), located in the Eastern Andean Cordillera, in the central part of Colombia, over several days. Assuming that large earthquakes may generate these types of anomalies, we identified positive results for the Mesetas earthquake (Mw6.0, Lon = 74.184° W, Lat = 3.462° N, H = 13 km-depth, 24 December 2019, UTC 19:03:55), with anomalies registered eight hours before the mainshock. The depth at which the resistivity anomaly was identified coincides with the depth of the earthquake hypocenter. The origin of these anomalies may be associated with the migration of fluids due to the change in the stress regime before, during, and after the earthquake. We hypothesize that before the occurrence of an earthquake, the stress field generates pore pressure gradients, promoting alterations in fluid migration that change the resistivity of the upper crust. Full article

Nature-Based Solutions for Integrated Water Resources Management (NbS-IWRM) involve natural, or nature-mimicking, processes used to improve water availability in quantity and quality sustainably, reduce the risks of water-related disasters, enhance adaptation to climate change and increase both biodiversity and the social-ecological system’s resilience. United Nations and the European Commission promote their research as a cornerstone in the changeover to the Ecological Transition. In the Sierra Nevada range (Spain) and the Andean Cordillera, there is a paradigmatic and ancestral example of NbS-IWRM known as “careo channels” and “amunas”, respectively. They recharge slope aquifers in mountain areas and consist of an extensive network of channels that infiltrate the runoff water generated during the snow-thawing and rainy season into the upper parts of the slopes. The passage of water through the aquifers in the slope is used to regulate the water resources of the mountain areas and thus ensure the duration of water availability for the downstream local population and generate multiple ecosystem services. This form of water management is known as Water Sowing and Harvesting (WS&H). As shown in this work, it is a living example of a resilience and climate change adaptation tool that can be qualified as a nature-based solution. Full article

This study focuses on hydrothermal alteration, and more specifically clays, in the geothermal reservoir of Cerro Pabellón in Andean Cordillera, Northern Chile. Although it is the first commercial geothermal power plant in South America with 48 MWe installed and an additional 33 MWe during 2022, the alteration mineralogy of the deep reservoir remains poorly investigated. Cuttings from two deep wells drilled between 500 and 3000 m depth were sampled. The fine-grained clay fraction was analyzed using X-ray diffraction to observe the mineral distribution and variations of crystal structure of the clays. Scanning electron microscopy coupled with energy dispersive spectroscopy allowed us to perform microanalysis of the clays. The results suggest a high heterogeneity of the reservoir in term of alteration: a pervasive alteration dominated by trioctahedral clays was observed in all the samples, whereas a fracture-controlled alteration was only observed locally, dominated by dioctahedral clays. Illite-smectite mixed layers with more than 90% illite typically occur in permeable fracture and fault as a typical clay signature. This study completed an integrated conceptual model of the high enthalpy reservoir (>250 °C). Circulations of a neutral pH Na-K-Cl fluid occur in a wide fracture system connected to highly dipping and NW-striking faults and could extend beyond the Pabelloncito graben. Full article

Exact knowledge of the physical structures of different river sections that govern their ecological structure and function is essential for the efficient conservation and management of riverine ecosystems. Eleven Andean river basins (Maipo, Rapel, Mataquito, Maule, Itata, Biobío, Toltén, Valdivia, Bueno and Puelo) comprise large scale latitudinal and altitudinal gradients and accommodate 71% of the Chilean population that strongly depend on their ecosystem services. Here, based on 16 hydrogeomorphic variables (on basin, valley and channel scales), we assessed the riverine landscapes (Functional Process Zones; FPZs) of these river basins using a top-down multivariate statistical approach. Two steep valley and downstream slope FPZs, three sinuous FPZs and two braided FPZs emerged in 8906 river sections. The proportion of the occurrence of FPZs was characterised by a clear latitudinal pattern which is strongly related to the proportions of each river basin within the large morphostructural units of Chile. As such, the proportion of each river basin within the Andes Cordillera, Central Valley and Coastal Cordillera is a strong driver of the fluvial geomorphology and, thus, of the FPZs’ arrangement in each river network. FPZ classification captured geomorphic diversity that coincided with the latitudinal and altitudinal gradients of Chilean Andean river basins strongly related to the hydrological characteristics of the assessed river basins and large scale spatial distribution of fish fauna endemism. As such, the identified large geomorphic units (FPZs) that are strongly tied up with hydrology and ecology hierarchies of riverine landscape provide robust operational tools that can be instrumental for river ecosystem monitoring and management at a basin scale. Full article

Located in northern Peru, at the lowest segment of the Central Andes, the Bagua Basin contains a Campanian to Pleistocene sedimentary record that archives the local paleoenvironmental and tectonic history. We present new δ¹⁸O and δ¹³C signatures of pedogenic carbonate nodules from paleosols in the Campanian–Maastrichtian Fundo El Triunfo Formation and in the upper Eocene–middle Miocene Sambimera Formation to reconstruct the isotopic composition of paleo-meteoric water and the floristic biome. We compare these results to modern isotopic values from a newly obtained modern water transect to interpret the environmental evolution of this area and its relationship with the neighboring Eastern Cordillera. A ~2‰ δ¹⁸O depletion between the latest Cretaceous and the latest Eocene reflects a shift from a coastal to inland environment. A negative δ¹⁸O shift of ~3‰ from the middle Miocene to the present day reveals the establishment of the Eastern Cordillera as an orographic barrier for the moisture traveling westward, sometime after deposition of the top of the Sambimera Formation at ~13 Ma. A shift in the δ¹³C signature from ~−25‰ in the Campanian–Miocene deposits to ~−23‰ in modern–Holocene times suggests a change in biome from dominant C3 plants to a mixture of C3 and C4 plants. This environmental shift reflects both the late Miocene global C4 expansion and the transition to more arid conditions in the basin. The Campanian–middle Miocene environmental reconstruction of the Bagua Basin indicates a steady paleoelevation setting in the northernmost Central Andes during most of the Cenozoic and constrains the uplift of the Eastern Cordillera to the late Miocene–Pleistocene. This paleoelevation history contrasts with that of the Central Andean Plateau, which is characterized by two major episodes of surface uplift: early–middle Miocene and late Miocene–Pliocene. The contrasting modern topographic configuration of the Central Andean Plateau and the northernmost Central Andes gives rise to the question of what factors created such a dramatic difference in topographic evolution of the two regions that shared an overall common tectonic history. We discuss the possible factors responsible for this contrasting topographic configuration and suggest that the diachronous flat slab episodes are likely a major factor, resulting in greater shortening and crustal thickness and, ultimately, in earlier surface uplift episodes occurring in the Central Andean Plateau. Full article

The Andes are defined by human struggles to provide for, and control, water. Nowhere is this challenge more apparent than in the unglaciated western mountain range Cordillera Negra of the Andes where rain runoff provides the only natural source of water for herding and farming economies. Based on over 20 years of systematic field surveys and taking a political ecology and resilience theory focus, this article evaluates how the Prehispanic North-Central highlands Huaylas ethnic group transformed the landscape of the Andes through the largescale construction of complex hydraulic engineering works in the Cordillera Negra of the Ancash Province, North-Central Peru. It is likely that construction of these engineered landscapes commenced during the Middle Horizon (AD 600–1000), reaching their apogee under the Late Intermediate Period (Huaylas group, AD 1000–1450) and Inca (AD 1450–1532) period, before falling into disuse during the early Spanish colony (AD 1532–1615) through a combination of disease, depopulation, and disruption. Persistent water stress in the western Pacific-facing Andean cordillera was ameliorated through the construction of interlinked dams and reservoirs controlling the water, soil, and wetlands. The modern study of these systems provides useful case-studies for infrastructure rehabilitation potentially providing low-cost, though technologically complex, solutions to modern water security. Full article