Holocene variations in Lake Titicaca water level and their implications for sociopolitical developments in the central Andes.

Holocene climate in the high tropical Andes was characterized by both gradual and abrupt changes, which disrupted the hydrological cycle and impacted landscapes and societies. High-resolution paleoenvironmental records are essential to contextualize archaeological data and to evaluate the sociopolitical response of ancient societies to environmental variability. Middle-to-Late Holocene water levels in Lake Titicaca were reevaluated through a transfer function model based on measurements of organic carbon stable isotopes, combined with high-resolution profiles of other geochemical variables and paleoshoreline indicators. Our reconstruction indicates that following a prolonged low stand during the Middle Holocene (4000 to 2400 BCE), lake level rose rapidly ~15 m by 1800 BCE, and then increased another 3 to 6 m in a series of steps, attaining the highest values after ~1600 CE. The largest lake-level increases coincided with major sociopolitical changes reported by archaeologists. In particular, at the end of the Formative Period (500 CE), a major lake-level rise inundated large shoreline areas and forced populations to migrate to higher elevation, likely contributing to the emergence of the Tiwanaku culture.

Miocene surface uplift and orogenic evolution of the southern Andean Plateau (central Puna), northwestern Argentina.

We present stable hydrogen-isotope analyses of volcanic glass ([Formula: see text]Dg) and radiometric ages (U-Pb zircon, U-Th calcite, AMS14C) from deformed sedimentary deposits in the vicinity of the intermontane Pocitos Basin in the central Puna of the Andean Plateau at about 24.5°S. Our results demonstrate 2-km surface uplift since the middle to late Miocene and protracted shortening that persists until the present day, while other sectors of the Puna show evidence for tectonically neutral and/or extensional settings. These findings are at odds with previous studies suggesting near-modern elevations (4 km) of the Puna Plateau since the late Eocene and formation of the intermontane Miocene Arizaro-Pocitos Basin associated with gravitational foundering of a dense lithosphere. Geophysical and geochemical data support the removal of continental lithosphere beneath the Puna, but the timing and mechanisms by which this removal occurs have remained controversial. We hypothesize that intermontane basin formation in the central Puna is the result of crustal shortening since about 20 Ma, followed by rapid surface uplift, likely related to lithospheric delamination.

Topsoil and subsoil bacterial community assemblies across different drainage conditions in a mountain environment.

BACKGROUND: High mountainous environments are of particular interest as they play an essential role for life and human societies, while being environments which are highly vulnerable to climate change and land use intensification. Despite this, our knowledge of high mountain soils in South America and their microbial community structure is strikingly scarce, which is of more concern considering the large population that depends on the ecosystem services provided by these areas. Conversely, the Central Andes, located in the Mediterranean region of Chile, has long been studied for its singular flora, whose diversity and endemism has been attributed to the particular geological history and pronounced environmental gradients in short distances. Here, we explore soil properties and microbial community structure depending on drainage class in a well-preserved Andean valley on the lower alpine vegetation belt (~2500 m a.s.l.) at 33.5˚S. This presents an opportunity to determine changes in the overall bacterial community structure across different types of soils and their distinct layers in a soil depth profile of a highly heterogeneous environment. METHODS: Five sites closely located (<1.5 km) and distributed in a well preserved Andean valley on the lower alpine vegetation belt (~2500 m a.s.l.) at 33.5˚S were selected based on a pedological approach taking into account soil types, drainage classes and horizons. We analyzed 113 soil samples using high-throughput sequencing of the 16S rRNA gene to describe bacterial abundance, taxonomic composition, and co-occurrence networks. RESULTS: Almost 18,427 Amplicon Sequence Variant (ASVs) affiliated to 55 phyla were detected. The bacterial community structure within the same horizons were very similar validating the pedological sampling approach. Bray-Curtis dissimilarity analysis revealed that the structure of bacterial communities in superficial horizons (topsoil) differed from those found in deep horizons (subsoil) in a site-specific manner. However, an overall closer relationship was observed between topsoil as opposed to between subsoil microbial communities. Alpha diversity of soil bacterial communities was higher in topsoil, which also showed more bacterial members interacting and with higher average connectivity compared to subsoils. Finally, abundances of specific taxa could be considered as biological markers in the transition from topsoil to subsoil horizons, like Fibrobacterota, Proteobacteria, Bacteroidota for shallower soils and Chloroflexi, Latescibacterota and Nitrospirota for deeper soils. CONCLUSIONS: The results indicate the importance of the soil drainage conditions for the bacterial community composition, suggesting that information of both structure and their possible ecological relationships, might be useful in clarifying the location of the edge of the topsoil-subsoil transition in mountainous environments.

Holistic rockfall risk assessment in high mountain areas affected by seismic activity: Application to the Uspallata valley, Central Andes, Chile.

Over large regions exposed to natural disasters, cascading effects resulting from complex or concatenated natural processes may represent a large portion of total risk. Populated high-mountain environments are a major concern, and methods for large-scale quantitative risk analyses are urgently required to improve risk mitigation. This article presents a comprehensive quantitative rockfall risk assessment over a large archetypal valley of the Andean mountains, in Central Chile, which integrates a wide spectrum of elements at risk. Risk is expressed as an expected damage both in monetary terms and casualties, at different scales relevant for decision making. Notably, total rockfall risk is divided into its main drivers, which allows quantifying seismically induced rockfall risk. For this purpose, the local seismic hazard is quantified and the yield acceleration, that is, acceleration required to initiate rockfall, is determined at the regional scale. The probability of failure is thereafter derived in terms of annual frequency of rockfall initiation and integrated in the quantitative risk assessment (QRA) process. Our results show the significant role of seismic activity as the triggering mechanism of rockfalls, and highlight elements at risk that have a major contribution to the total risk. Eventually a sensitivity analysis is conducted to (i) assess the robustness of obtained risk estimates to the data and modeling choices and (ii) identify the most influential assumptions. Our approach evidences the feasibility of large-scale QRAs in sensitive environments and opens perspectives for refining QRAs in similar territories significantly affected by cascading effects and multihazards.

Field Campaign Evaluation of Sensors Lufft GMX500 and MaxiMet WS100 in Peruvian Central Andes.

The research presents the inter-comparison of atmospheric variables measured by 9 automatic weather stations. This set of data was compared with the measurements of other weather stations in order to standardize the values that must be adjusted when taken to different areas. The data of a set of a total of 9 GMX500, which measures conventional meteorological variables, and 10 WS100 sensors, which measures precipitation parameters. The automatic stations were set up at the Huancayo Observatory (Geophysical Institute of Peru) for a period of 5 months. The data set of GMX500 were evaluated comparing with the average of the 9 sensors and the WS100 was compared with an optical disdrometer Parsivel2. The temperature, pressure, relative humidity, wind speed, rainfall rate, and drop size distribution were evaluated. A pair of GMX500 sensors presented high data dispersion; it was found found that the errors came from a bad configuration; once this problem was solved, good agreement was archived, with low RMSE and high correlation. It was found that the WS100 sensors overestimate the precipitation with a percentage bias close to 100% and the differences increase with the greater intensity of rain. The drop size distribution retrieved by WS100 have unrealistic behavior with higher concentrations in diameters of 1 mm and 5 mm, in addition to a flattened curve.

Compositional data supports decentralized model of production and circulation of artifacts in the pre-Columbian south-central Andes.

The circulation and exchange of goods and resources at various scales have long been considered central to the understanding of complex societies, and the Andes have provided a fertile ground for investigating this process. However, long-standing archaeological emphasis on typological analysis, although helpful to hypothesize the direction of contacts, has left important aspects of ancient exchange open to speculation. To improve understanding of ancient exchange practices and their potential role in structuring alliances, we examine material exchanges in northwest Argentina (part of the south-central Andes) during 400 BC to AD 1000 (part of the regional Formative Period), with a multianalytical approach (petrography, instrumental neutron activation analysis, laser ablation inductively coupled plasma mass spectrometry) to artifacts previously studied separately. We assess the standard centralized model of interaction vs. a decentralized model through the largest provenance database available to date in the region. The results show: (i) intervalley heterogeneity of clays and fabrics for ordinary wares; (ii) intervalley homogeneity of clays and fabrics for a wide range of decorated wares (e.g., painted Ciénaga); (iii) selective circulation of two distinct polychrome wares (Vaquerías and Condorhuasi); (iv) generalized access to obsidian from one major source and various minor sources; and (v) selective circulation of volcanic rock tools from a single source. These trends reflect the multiple and conflicting demands experienced by people in small-scale societies, which may be difficult to capitalize by aspiring elites. The study undermines centralized narratives of exchange for this period, offering a new platform for understanding ancient exchange based on actual material transfers, both in the Andes and beyond.

Late Archaic-Early Formative period microbotanical evidence for potato at Jiskairumoko in the Titicaca Basin of southern Peru.

The data presented in this paper provide direct microbotanical evidence concerning the early use of potato (Solanum tuberosum) within its botanical locus of origin in the high south-central Andes. The data derive from Jiskairumoko, an early village site in the western Titicaca Basin dating to the Late Archaic to Early Formative periods (∼3,400 cal y BC to 1,600 cal y BC). Because the site reflects the transition to sedentism and food production, these data may relate to potato domestication and early cultivation. Of 141 starch microremains recovered from 14 groundstone tools from Jiskairumoko, 50 are identified as consistent with cultivated or domesticated potato, based on reference to published materials and a study of wild and cultivated potato starch morphology. Along with macro- and microbotanical evidence for chenopod consumption and grinding tool data reflecting intensive use of this technology throughout site occupation, the microbotanical data reported here suggest the intensive exploitation, if not cultivation, of plant resources at Jiskairumoko. Elucidating the details of the trajectory of potato domestication is necessary for an overall understanding of the development of highland Andean agriculture, as this crop is central to the autochthonous agricultural suite. A paucity of direct botanical evidence, however, has hindered research efforts. The results of the modern and archaeological starch analyses presented here underscore the utility of this method in addressing questions related to the timing, mode, and context of potato origins.

Slow Long-Term Exhumation of the West Central Andean Plate Boundary, Chile.

We present a regional analysis of new low-temperature thermochronometer ages from the Central Andean fore arc to provide insights into the exhumation history of the western Andean margin. To derive exhumation rates over 10 million-year timescales, 38 new apatite and zircon (U-Th)/He ages were analyzed along six ~500-km long near-equal-elevation, coast parallel, transects in the Coastal Cordillera (CC) and higher-elevation Precordillera (PC) of the northern Chilean Andes between latitudes 18.5°S and 22.5°S. These transects were augmented with age-elevation profiles where possible. Results are synthesized with previously published thermochronometric data, corroborating a previously observed trenchward increase in cooling ages in Peru and northern Chile. One-dimensional thermal-kinematic modeling of all available multichronometer equal-elevation samples reveals mean exhumation rates of <0.2 km/Myr since ~50 Ma in the PC and ~100 Ma in the CC. Regression of pseudovertical age-elevation transects in the CC yields comparable rates of ~0.05 to ~0.12 km/Myr between ~40 and 80 Ma. Differences between the long-term mean 1-D rates and shorter-term age-elevation-derived rates indicate low variability in the exhumation history. Modeling results suggest similar background exhumation rates in the CC and PC; younger ages in the PC are largely a function of increased heat flow and consequently an elevated geothermal gradient near the arc. Slow exhumation rates are suggestive of semiarid conditions across the region since at least the Eocene and deformation and development of the Andean fore arc around this time.

Aqueous extract of yellow maca (Lepidium meyenii) improves sperm count in experimental animals but response depends on hypocotyl size, pH and routes of administration.

Lepidium meyenii, a Peruvian plant growing over 4000 m.a.s.l., has effects on nutrition and fertility. The purpose of this study was to evaluate the sperm count in 105 male mice receiving boiled aqueous extract of yellow maca hypocotyls from different sizes, under different pH conditions and using two different routes of administration. Five mice per group were treated daily for 3 days with vehicle (oral and intraperitoneal) or maca aqueous extracts (5 mg/0.5 ml/day) belonging to the first, second, third and fourth categories, according to their hypocotyl size. On day four, sperm count was evaluated at testis, epididymis and vas deferens. Sperm count was higher in mice receiving maca from the larger sizes (first and second categories). Reduction in maca extract pH increased sperm count, whereas an increase in the pH resulted in a reduction in sperm count. The effect of pH reduction is observed only in maca from the first and second categories. Aqueous extract of maca was effective only after oral administration. In conclusion, the larger size of hypocotyls presented the best biological effect, and the low pH in the extract and the transformation after gastrointestinal passage are both important for its biological action.

Ecological range shift in the polyploid members of the South American genus Fosterella (Bromeliaceae).

Background and Aims: The distribution of polyploidy along a relatively steep Andean elevation and climatic gradient is studied using the genus Fosterella L.B. Sm. (Bromeliaceae) as a model system. Ecological differentiation of cytotypes and the link of polyploidy with historical biogeographic processes such as dispersal events and range shift are assessed. Methods: 4',6-Diamidino-2-phenylindole (DAPI) staining of nuclei and flow cytometry were used to estimate the ploidy levels of 159 plants from 22 species sampled throughout the distribution range of the genus. Ecological differentiation among ploidy levels was tested by comparing the sets of climatic variables. Ancestral chromosome number reconstruction was carried out on the basis of a previously generated phylogeographic framework. Key Results: This study represents the first assessment of intrageneric, intraspecific and partially intrapopulational cytotype diversity in a genus of the Bromeliaceae family. In Fosterella , the occurrence of polyploidy was limited to the phylogenetically isolated penduliflora and rusbyi groups. Cytotypes were found to be ecologically differentiated, showing that polyploids preferentially occupy colder habitats with high annual temperature variability (seasonality). The combined effects of biogeographic history and adaptive processes are presumed to have shaped the current cytotype distribution in the genus. Conclusions: The results provide indirect evidence for both adaptive ecological and non-adaptive historical processes that jointly influenced the cytotype distribution in the predominantly Andean genus Fosterella (Bromeliaceae). The results also exemplify the role of polyploidy as an important driver of speciation in a topographically highly structured and thus climatically diverse landscape.

Investigating economic specialization on the central Peruvian coast: A reconstruction of Late Intermediate Period Ychsma diet using stable isotopes.

OBJECTIVES: Hypothetical models of socioeconomic organization in pre-Columbian societies generated from the rich ethnohistoric record in the New World require testing against the archaeological and bioarchaeological record. Here, we test ethnohistorian Maria Rostworowski's horizontality model of socioeconomic specialization for the Central Andean coast by reconstructing dietary practices in the Late Intermediate Period (c. AD 900-1470) Ychsma polity to evaluate complexities in social behaviors prior to Inka imperial influence. MATERIALS AND METHODS: Stable carbon and nitrogen isotope analysis of archaeological human bone collagen and apatite (δ13 Ccol[VPDB], δ15 Ncol[AIR] , δ13 Cap[VPDB] ) and locally available foods is used to reconstruct the diets of individuals from Armatambo (n = 67), associated ethnohistorically with fishing, and Rinconada Alta (n = 46), associated ethnohistorically with agriculture. RESULTS: Overall, mean δ15 Ncol[AIR] is significantly greater at Armatambo, while mean δ13 Ccol[VPDB] and mean δ13 Cap[VPDB] are not significantly different between the two sites. Within large-scale trends, adult mean δ13 Cap[VPDB] is significantly greater at Armatambo. In addition, nearly one-third of Armatambo adults and adolescents show divergent δ15 Ncol[AIR] values. DISCUSSION: These results indicate greater reliance on marine resources at Armatambo versus Rinconada Alta, supporting the ethnohistoric model of socioeconomic specialization for the Central Andean coast. Deviations from large-scale dietary trends suggest complexities not accounted for by the ethnohistoric model, including intra-community subsistence specialization and/or variation in resource access.

Comparative phylogeography of co-distributed Phrygilus species (Aves, Thraupidae) from the Central Andes.

The Neotropical ecoregion has been an important place of avian diversification where dispersal and allopatric events coupled with periods of active orogeny and climate change (Late Pliocene-Pleistocene) have shaped the biogeography of the region. In the Neotropics, avian population structure has been sculpted not only by geographical barriers, but also by non-allopatric factors such as natural selection and local adaptation. We analyzed the genetic variation of six co-distributed Phrygilus species from the Central Andes, based on mitochondrial and nuclear markers in conjunction with morphological differentiation. We examined if Phrygilus species share patterns of population structure and historical demography, and reviewed the intraspecific taxonomy in part of their geographic range. Our results showed different phylogeographic patterns between species, even among those belonging to the same phylogenetic clade. P. alaudinus, P. atriceps, and P. unicolor showed genetic differentiation mediated by allopatric mechanisms in response to specific geographic barriers; P. gayi showed sympatric lineages in northern Chile, while P. plebejus and P. fruticeti showed a single genetic group. We found no relationship between geographic range size and genetic structure. Additionally, a signature of expansion was found in three species related to the expansion of paleolakes in the Altiplano region and the drying phase of the Atacama Desert. Morphological analysis showed congruence with molecular data and intraspecific taxonomy in most species. While we detected genetic and phenotypic patterns that could be related to natural selection and local adaptation, our results indicate that allopatric events acted as a major factor in the population differentiation of Phrygilus species.

Pleistocene climatic oscillations rather than recent human disturbance influence genetic diversity in one of the world's highest treeline species.

PREMISE OF THE STUDY: Biological responses to climatic change usually leave imprints on the genetic diversity and structure of plants. Information on the current genetic diversity and structure of dominant tree species has facilitated our general understanding of phylogeographical patterns. METHODS: Using amplified fragment length polymorphism (AFLPs), we compared genetic diversity and structure of 384 adults of P. tarapacana with those of 384 seedlings across 32 forest sites spanning a latitudinal gradient of 600 km occurring between 4100 m and 5000 m a.s.l. in Polylepis tarapacana (Rosaceae), one of the world's highest treeline species endemic to the central Andes. KEY RESULTS: Moderate to high levels of genetic diversity and low genetic differentiation were detected in both adults and seedlings, with levels of genetic diversity and differentiation being almost identical. Four slightly genetically divergent clusters were identified that accorded to differing geographical regions. Genetic diversity decreased from south to north and with increasing precipitation for adults and seedlings, but there was no relationship to elevation. CONCLUSIONS: Our study shows that, unlike the case for other Andean treeline species, recent human activities have not affected the genetic structure of P. tarapacana, possibly because its inhospitable habitat is unsuitable for agriculture. The current genetic pattern of P. tarapacana points to a historically more widespread distribution at lower altitudes, which allowed considerable gene flow possibly during the glacial periods of the Pleistocene epoch, and also suggests that the northern Argentinean Andes may have served as a refugium for historical populations.

The "sowing of concrete": Peri-urban smallholder perceptions of rural-urban land change in the Central Peruvian Andes.

Policy makers concerned with the peri-urban interface find their greatest challenges in the rapid urban growth of developing mountain regions, since limitations caused by relief and altitude often lead to an increased competition between rural and urban land use at the valley floors. In this context, little attention has been paid to the affected agriculturalists' perceptions of peri-urban growth-important information required for the realization of sustainable land use planning. How is the process of rural-urban land change perceived and assessed by peri-urban smallholder communities? Which are the major difficulties to be overcome? By what means are the affected people reacting and how are these adaptation strategies linked with the ongoing landscape transformations of the hinterland? By using the example of Huancayo Metropolitano, an emerging Peruvian mountain city, it is shown that rural-urban land change is intensively discussed within peri-urban smallholder groups. Although urbanization also leads to infrastructure investments by public institutions-an advantage perceived throughout the study area-the negative impacts of rural-urban land use change prevail. The perceptions' analysis reveals that the decrease of fertile and irrigated agricultural land at the quechua valley floor is especially considered to threaten subsistence, food and income security. In order to compensate the loss of production capacities, many smallholders try to expand or intensify their land use at the suni altitudinal belt: an agro-ecological zone characterized by steep and nonirrigated slopes that can actually not be used for the year-round production of crops previously cultivated at the quechua zone.

Foggy connections, cloudy frontiers: On the (non-)adaptation of lexical structures.

While research on possible adaptive processes in language history has recently centered mostly on phonological variables, here, I return the focus on the lexicon in two different ways. First, I take up the familiar theme of the responsiveness of language structure to the local conditions at different elevations of the earth's surface by exploring further the idea that language communities at high altitudes may tend not to distinguish lexically, as, e.g., English does, between "cloud" and "fog." Analyses of a global dataset of languages as well as in-depth study of the languages of the Central Andes are consistent in showing a wide spread of colexification of "cloud" and "fog" across elevations, whereas distinguishing languages tend more to be spoken at lower elevations. Statistically, there is global support for the idea that colexification is triggered by high elevation, but a closer look, in particular at the Andean dataset, paints a more nuanced picture. Concretely, it shows that in some language families, there are consistent preferences for either colexifying or distinguishing between "cloud" and "fog." In particular, the behavior of the large Quechuan family, which ranges across high- and low-elevation environments but still is consistently colexifying, shows no evidence for adaptive processes within language families. This result is open to various interpretations and explanations, for they suggest lineage-specific preferences for or against colexification that run counter to global trends. It is also at odds with the notions of "efficient communication" and "communicative need" as far as they relate to lexical categories and bars mechanistic or deterministic views on the processes in which the categories of languages are molded.

Elevational range extension of the Puna Mouse, Punomys (Cricetidae), with the first record of the genus from Chile.

We report an elevational record for the Andean sigmodontine Puna Mouse Punomys, which is also the first record of the genus in Chile. The record is based on a mummified specimen that we discovered at an elevation of 5,461 m (17,917 feet) in the caldera of Volcán Acamarachi, Región de Antofagasta, Chile. Results of a morphological assessment suggest that the specimen can be provisionally referred to the species P. lemminus. This new record also extends the known geographic distribution of the genus by 700 km to the south and brings the known Chilean mammal richness to a total of 170 living species and 88 genera. This finding highlights the need for increased survey efforts in more remote, high-elevation regions and demonstrates that there is still much to be learned about the mammal fauna of the Andean Altiplano.

Se reporta un registro altitudinal para el roedor sigmodontino Punomys, el cual corresponde a su vez al primer hallazgo del género para Chile. Este se basa en un espécimen momificado encontrado a una elevación de 5,461 m en la caldera del Volcán Acamarachi, Región de Antofagasta, Chile. Los caracteres morfológicos sugieren que el espécimen puede ser referido provisionalmente a la especie P. lemminus. Este nuevo registro amplía la distribución geográfica conocida del género en 700 km al sur, y eleva la riqueza de mamíferos vivientes chilenos a un nuevo total de 170 especies y 88 géneros. Este hallazgo resalta la necesidad de aumentar los esfuerzos de prospección en las regiones más remotas y de mayor altitud y demuestra que aún queda mucho por aprender sobre el ensamble de los mamíferos del Altiplano andino.

Vivid valleys, pallid peaks? Hypsometric variations and rural-urban land change in the Central Peruvian Andes.

What happens to the land cover within the hinterland's altitudinal belts while Central Andean cities are undergoing globalization and urban restructuring? What conclusions can be drawn about changes in human land use? By incorporating a regional altitudinal zonation model, direct field observations and GIS analyses of remotely sensed long term data, the present study examines these questions using the example of Huancayo Metropolitano - an emerging Peruvian mountain city of 420,000 inhabitants, situated at 3260 m asl in the Mantaro Valley. The study's results indicate that rapid urban growth during the late 1980s and early 1990s was followed by the agricultural intensification and peri-urban condominization at the valley floor (quechua) - since the beginning of Peru's neoliberal era. Moreover, regarding the adjoining steep slopes (suni) and subsequent grassland ecosystems (puna), the research output presents land cover change trajectories that clearly show an expansion of human land use, such as reforestation for wood production and range burning for livestock grazing, even at high altitudes - despite rural-urban migration trends and contrary to several results of extra-Andean studies. Consequently, rural-urban planners and policy makers are challenged to focus on the manifold impacts of globalization on human land use - at all altitudinal belts of the Andean city's hinterland: toward sustainable mountain development that bridges the social and physical gaps - from the bottom up.

New Records of the Andean Cat (Leopardus jacobita) in the Central Andes of Chile: Filling Gaps in the Distribution Range through Private-Social Partnerships.

The Andean cat (Leopardus jacobita) is one of the most endangered and least known wild cat species in the Americas and the world in general. We describe new records of the Andean cat in the central Andes of Chile, in Parque Andino Juncal, obtained as part of a monitoring program conducted from December 2020 to May 2021 using eight trail cameras. The cameras were active for 135 days (sampling effort 1080 camera-trap days). We recorded Andean cats in two different cameras, corresponding to two independent events in January and March 2021, respectively (0.19% capture success). Our new records are relevant since they fill a gap on the species distribution map, specifically in the area located between the two previously identified evolutionarily significant units (ESU) (26-35° S) which has been prioritized by the Andean Cat Alliance (AGA). We highlight the relevance of private protected areas in ecosystems of high biodiversity and fragility such as Parque Andino Juncal and also of strategic private-social partnerships for successful collaborative efforts to monitor the presence of rare, elusive, and endangered species. Our next steps will be to collect scats from this newly identified site and conduct genetic analyses to determine whether these animals are part of previously identified ESUs or a yet unidentified potentially distinct ESU or MU requiring special conservation measures.

Plume moths (Lepidoptera, Pterophoridae) reared from the Chilean endemic Steviaphilippiana (Asteraceae).

Background: The micromoth fauna of the arid environments of the western slopes of central Andes remains poorly explored. Plants native to this area host overlooked species. A survey for micromoth larvae on the Chilean endemic Steviaphilippiana Hieron. (Asteraceae) was performed. New information: The first records of plume moths (Lepidoptera, Pterophoridae) associated with S.philippiana are provided. Adults of Adainajobimi Vargas, 2020 and a new species of Oidaematophorus Wallengren, 1862 were reared from larvae collected on inflorescences and leaves, respectively. Oidaematophorusandresi sp. n. is described and illustrated. A phylogenetic analysis of mitochondrial DNA sequences clustered each of the two plume moths with the type species of its respective genus. These records expand the host plant range of A.jobimi and add a second species of Oidaematophorus to the Chilean fauna of plume moths.

Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world's highest elevation tree species.

Tree growth is generally considered to be temperature limited at upper elevation treelines, yet climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polylepis tarapacana Philipi, the world's highest elevation tree species, which is found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4400 m in elevation, along a 500 km latitude aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon sink processes along the gradient. Current growing-season temperature regulated RWI at northern-wetter sites, while prior growing-season precipitation determined RWI at arid southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site water availability. By contrast, warm and dry growing seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes along the gradient. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. This manuscript also highlights a coupling (decoupling) between physiological processes at leaf level and wood formation as a function of similarities (differences) in their climatic sensitivity. This study contributes to a better understanding and prediction of the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.