https://ipt.mincyt.gob.ar/resource?r=transect_bettles Paula Sackmann Laboratorio Ecotono, CRUB - (CONICET - Universidad Nacional del Comahue)

Bariloche Rio Negro AR

Mario Elgueta Área de Entomología, Museo Nacional de Historia Natural (MNHN)

Santiago Región Metropolitana de Santiago 8320000 CL

Gustavo E. Flores Laboratorio de Entomología, Instituto Argentino de Investigaciones de las Zonas Áridas - IADIZA (CCT-CONICET Mendoza)

Mendoza Mendoza 5500 AR

Marcelo Kun Departamento de Zoología. CRUB (Universidad Nacional del Comahue)

Bariloche Río Negro 8400 AR

Federico Ocampo Elytron Biotech S.A.

Ciudad Autónoma de Buenos Aires - CABA Buenos Aires 1001 AR

Paula Posadas Laboratorio de Sistemática y Biología Evolutiva – Universidad Nacional de La Plata, Facultad de Ciencias Naturales y Museo (UNLP)

La Plata Buenos Aires 1900 AR

Sergio Roig-Juñent Laboratorio de Entomología, Instituto Argentino de Investigaciones de las Zonas ´Áridas, IADIZA (CCT-CONICET Mendoza)

Mendoza Mendoza 5500 AR

Victoria Werenkraut Laboratorio de Investigaciones en Hormigas (LIHO), Instituto de Investigaciones en Biodiversidad y Medioambiente, INIBIOMA (CONICET–Universidad Nacional del Comahue)

Bariloche Bariloche 8400 AR

Adriana Ruggiero Laboratorio Ecotono, Instituto de Investigaciones en Biodiversidad y Medioambiente, INIBIOMA (CONICET–Universidad Nacional del Comahue)

Bariloche Rio Negro 8400 AR

Victoria Werenkraut Instituto de Investigaciones en Biodiversidad y Medioambiente - INIBIOMA - (CONICET - Universidad Nacional del Comahue)

Bariloche Rio Negro 8400 AR

werenkraut@comahue-conicet.gob.ar Adriana Ruggiero Laboratorio Ecotono, Instituto de Investigaciones en Biodiversidad y Medioambiente, INIBIOMA (CONICET–Universidad Nacional del Comahue)

Bariloche Rio Negro 8400 AR

Adriana Ruggiero INIBIOMA - CONICET

Bariloche Río Negro AR

ruggieroa@comahue-conicet.gob.ar principalInvestigator Cecilia Ezcurra Departamento de Botánica. CRUB-Universidad Nacional del Comahue

Bariloche Rio Negro 8400 AR

principalInvestigator Alejandro G. Farji-Brener Laboratorio de Investigaciones en Hormigas (LIHO), Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA)/CONICET–Universidad Nacional del Comahue,

Bariloche Rio Negro 8400 AR

principalInvestigator 2025-07-22 eng This dataset comprises 1,946 occurrence records, documenting beetle diversity across 50 sampling sites established along five longitudinal transects spanning a 150 × 150 km study area at the transition between the Subantarctic forests and Patagonian steppes in northwestern Patagonia, Argentina. It is complemented by 900 environmental measurements, providing local ecological context for each site. The dataset is structured into four main components:Core Event Location Dataset: Provides geographical and administrative information for the 50 sampling sites, including coordinates and habitat types.Environmental Data: Comprises 900 records, documenting various environmental variables measured at each sampling location.Occurrence Data: Includes 1,946 records, reporting species occurrences with associated taxonomic classifications, individual counts, and data sources.Sub-Event Sampling: Consists of 250 records, describing sampling protocols, effort, and dates. Samplingevent GBIF Dataset Type Vocabulary: http://rs.gbif.org/vocabulary/gbif/dataset_type_2015-07-10.xml Beetles Northwestern Patagonia N/A This work is licensed under a Creative Commons Attribution Non Commercial (CC-BY-NC 4.0) License. Creative Commons Attribution Non Commercial 4.0 International https://spdx.org/licenses/CC-BY-NC-4.0.html CC-BY-NC-4.0 Northwestern Patagonia (Argentina) in the western region of the Río Negro and Neuquén provinces, approximately between 39°78'S and 41°45'S latitude and 70°37'W and 71.88°W longitude. -71.886684 -70.366678 -39.782046 -41.458541 2004-11-01 2004-11-30 2005-01-01 2005-01-31 2005-03-01 2005-03-31 2006-01-01 2006-01-31 2006-03-01 2006-03-31 This dataset consists of approximately 1,946 records, representing 9,430 individuals across 54 beetle families recorded across all sampling plots, encompassing 9,430 individuals. The distribution of occurrences across families varied widely, with some families being highly dominant while others were less represented. The collected specimens were distributed as follows: Carabidae (3,652 individuals, 38.7%), Leiodidae (1,953 individuals, 20.7%), Tenebrionidae (948 individuals, 10.1%), Trachypachidae (718 individuals, 7.6%), Staphylinidae (414 individuals, 4.4%), Cryptophagidae (272 individuals, 2.9%), Curculionidae (220 individuals, 2.3%), Scarabaeidae (208 individuals, 2.2%), Melandryidae (117 individuals, 1.2%), Histeridae (112 individuals, 1.2%), Cantharidae (99 individuals, 1.0%), Chrysomelidae (89 individuals, 0.9%), Nitidulidae (67 individuals, 0.7%), Melyridae (66 individuals, 0.7%), Elateridae (48 individuals, 0.5%), Meloidae (48 individuals, 0.5%), Geotrupidae (47 individuals, 0.5%), Mordellidae (35 individuals, 0.4%), Ptinidae (35 individuals, 0.4%), Archeocrypticidae (34 individuals, 0.4%), Lampyridae (33 individuals, 0.3%), Lucanidae (29 individuals, 0.3%), Brentidae (25 individuals, 0.3%), Anthicidae (21 individuals, 0.2%), Trogidae (19 individuals, 0.2%), Coccinellidae (14 individuals, 0.1%), Ptiliidae (14 individuals, 0.1%), Latridiidae (13 individuals, 0.1%), Scydmaenidae (12 individuals, 0.1%), Dascillidae (8 individuals, 0.1%), Attelabidae (7 individuals, 0.1%), Erotylidae (6 individuals, 0.1%), Anobiidae (6 individuals, 0.1%), Buprestidae (4 individuals, 0.0%), Cucujidae (4 individuals, 0.0%), Colonidae (4 individuals, 0.0%), Scirtidae (4 individuals, 0.0%), Pyrochroidae (3 individuals, 0.0%), Cybocephalidae (3 individuals, 0.0%), Silvanidae (2 individuals, 0.0%), Nemonychidae (2 individuals, 0.0%), Protocucujidae (2 individuals, 0.0%), Dermestidae (2 individuals, 0.0%), Trogossitidae (1 individual, 0.0%), Agyrtidae (1 individual, 0.0%), Phloeostichidae (1 individual, 0.0%), Phalacridae (1 individual, 0.0%), Nosodendridae (1 individual, 0.0%), Hydrophilidae (1 individual, 0.0%), Cleridae (1 individual, 0.0%), Ciidae (1 individual, 0.0%), Cerambycidae (1 individual, 0.0%), Bothrideridae (1 individual, 0.0%), Zopheridae (1 individual, 0.0%). phylum Arthropoda family Attelabidae family Zopheridae family Meloidae family Erotylidae family Trogossitidae family Trogidae family Protocucujidae family Histeridae family Cryptophagidae kingdom Animalia family Melyridae family Carabidae family Buprestidae family Phloeostichidae family Curculionidae family Agyrtidae family Ptiliidae family Latridiidae family Archeocrypticidae family Staphylinidae family Elateridae family Anobiidae order Coleoptera class Insecta family Nemonychidae family Colonidae family Geotrupidae family Mordellidae family Ptinidae family Cucujidae family Nosodendridae family Hydrophilidae family Cantharidae family Lampyridae family Melandryidae family Cybocephalidae family Scydmaenidae family Dascillidae family Bothrideridae family Scarabaeidae family Silvanidae family Pyrochroidae family Trachypachidae family Ciidae family Dermestidae family Coccinellidae family Leiodidae family Anthicidae family Chrysomelidae family Scirtidae family Cleridae family Cerambycidae family Brentidae family Tenebrionidae family Lucanidae family Nitidulidae family Phalacridae This dataset was created to investigate the spatial and temporal variation in the richness, abundance, and geographic distribution of epigaeic beetles across the transition zone between temperate subantarctic forests and Patagonian steppes in southern South America at approximately 39°S–42°S, 70°W–72°W. By documenting the abundance of epigaeic beetles in local assemblages during the southern spring (November) and summer (January and March) for three years (2004, 2005, 2006) alongside local environmental factors—including vegetation cover, temperature, precipitation, and soil conditions—this dataset offers valuable insights into the ecological correlates of beetle diversity and distribution in a dynamic transitional landscape. The spatial variation in biological diversity is largely shaped by environmental gradients, which arise primarily from climatic shifts and are often associated with changes in vegetation and soil conditions. These gradients, occurring along latitudinal, altitudinal, or longitudinal axes, frequently define ecotones or transition zones between biogeographical units. Such zones promote increased species turnover and the occurrence of key ecological and evolutionary processes. Beyond their role in structuring biodiversity, transitional areas foster dynamic ecological interactions and serve as critical regions for conservation, as they can enhance species' adaptive responses to environmental changes. When coupled with physiographic barriers such as rivers and mountain ranges, transition zones also contribute to taxonomic differentiation by restricting gene flow between populations, thereby maintaining distinct areas of endemism. (Endler, 1977; Smith et al., 2001).One consequence of biogeographic transitions is that species' geographic ranges can shift considerably, resulting in pronounced gradients in species richness, high spatial turnover, or a combination of both (e.g., Lomolino et al., 2010). Given their ecological significance, transitional zones are often priority areas for biodiversity conservation, particularly when they overlap with global biodiversity hotspots. Understanding the mechanisms that drive species diversity in these regions is therefore essential for predicting how biodiversity might respond to climate change and anthropogenic disturbances (Smith et al., 2001). However, effective conservation strategies require a detailed understanding of biodiversity patterns and the environmental factors shaping species distributions.To address this need, we compiled a dataset to investigate longitudinal variation in species richness, abundance, and geographic distribution of epigaeic beetles across the transition zone between temperate subantarctic forests and Patagonian steppes in southern South America. Indeed, the biogeographic transition between the Valdivian Province of the Subantarctic subregion and the Patagonian Province of the Patagonian subregion (sensu Morrone 2008), represents one of the most pronounced environmental gradients in the world. Precipitation varies dramatically along this east–west gradient, ranging from 500 mm to 3,000 mm over just 100 km (Barros et al., 1983). This gradient results in three distinct physiognomic units: forests, scrublands, and steppes (Paruelo et al., 1998b). Changes in beetle composition and abundance tend to follow these environmental shifts (e.g., Sackmann et al., 2006; Sackmann & Farji-Brener, 2006).However, previously available data on beetle diversity at a regional scale in this area were largely unstandardized in terms of sampling effort and methodology. To address this gap, our dataset provides systematically collected data on beetle composition, richness, and abundance using standardized spatial and temporal sampling methods. This dataset enables detailed ecological analyses of spatial variation in beetle abundance along the biogeographic transition.In addition to beetle species richness and local assemblage abundance, the dataset incorporates key environmental variables, including vegetation cover, temperature, precipitation, and soil conditions. By integrating species occurrence with abiotic and biotic factors, it provides valuable insights into the ecological drivers of beetle diversity and distribution in this dynamic landscape.Preliminary analyses of this dataset (Ruggiero et al., 2009) indicated that beetle abundance at this biogeographical transition is strongly influenced by tree canopy cover and, to a lesser extent, by herbaceous vegetation. However, the role of shrub cover varies across habitats: in the eastern scrubland-steppe, shrub cover positively affects beetle abundance, whereas in the western forested areas, its effect is negative. Temperature also plays a critical role. Minimum daily temperature shows weak or negative correlations with beetle abundance, while increased temperature variability exerts a consistently negative effect. These findings suggest that indirect climatic influences, particularly those mediated through plant cover, significantly shape beetle assemblages. Additionally, thermal limitation may operate locally through variations in daily temperature range, possibly affecting species' physiological tolerances and activity patterns.A separate analysis focusing on Tenebrionidae (darkling beetles) (Sackmann & Flores, 2006) revealed that total abundance peaked in late spring (November) and summer (January), whereas species richness remained relatively stable across sampling periods. Species richness was highest in the steppe and lowest in the scrubland, with assemblage composition differing between northern and southern transects. However, species composition showed little correlation with the measured environmental variables, suggesting that additional factors, such as dispersal limitation or historical biogeographic processes, may influence species distributions.These findings highlight the ecological complexity of transition zones and emphasize the importance of incorporating both biotic and abiotic factors when assessing biodiversity patterns. In the future, this dataset can be used as a baseline to explore broader ecological questions, including species responses to climate variability, habitat fragmentation, and land-use change. Additionally, it provides a valuable resource for comparative studies examining insect community dynamics across biogeographic boundaries. By making this dataset publicly available, we aim to facilitate further research into the ecological and evolutionary processes shaping species diversity in transitional landscapes. Understanding these processes is essential for developing informed conservation strategies that preserve biodiversity while promoting ecosystem resilience in the face of global environmental change. This dataset is structured to support biodiversity assessments, taxonomic verification, and ecological research. The information uploaded included the following files and structure:1) Core_Event_Location: This dataset provides georeferenced information on sampling events conducted across the 50 sampling locations, facilitating spatial and ecological analyses. Each record corresponds to a unique event, identified by an eventID, and includes details on the habitat type, administrative divisions, and precise geographic coordinates. The dataset is structured to ensure compatibility with global biodiversity databases and geospatial research applications, and consists of the following variables:eventID: A unique identifier for each sampling event.habitat: Describes the general habitat type where the sampling event took place (forest, scrubland, steppe).countryCode: The ISO 3166-1 alpha-2 code representing the country of the event ("AR" for Argentina).country: The full country name where the event was recorded.stateProvince: The administrative subdivision (province) within Argentina, where the event occurred.county: A more localized administrative division, typically a department.locality: A textual description of the closest city or municipality, indicating the location where the sampling event was conducted.decimalLongitude: The longitude coordinate of the event in decimal degrees (WGS84 reference system).decimalLatitude: The latitude coordinate of the event in decimal degrees (WGS84 reference system).geodeticDatum: The spatial reference system used for geographic coordinates (e.g., "WGS84").2) sub_event_muestreo1: This dataset contains detailed records of sampling sub-events conducted within the sampling event. Each record corresponds to a unique sub-event, identified by an eventID, and is linked to its parent event through the parentEventID. The dataset provides information about the date, sampling methodology and sampling effort, making it a valuable resource for biodiversity monitoring and ecological studies. This dataset includes the following variables:eventID: A unique identifier for each sampling sub-event, formatted to include the sampling plot (site), month, and year (e.g., LT1S1_NOV_2004).parentEventID: The identifier of the main sampling event (sampling plot) to which the sub-event belongs, ensuring hierarchical structuring of data.eventDate: The date (YYYY-MM format) when the sampling sub-event took place.samplingProtocol: A description of the sampling methodology used (pitfall trapping).samplingEffort: Additional information on the number and arrangement of pitfall traps established in the field.sampleSizeValue: The numerical value indicating the duration or extent of the sampling effort (e.g., number of days the traps were active).sampleSizeUnit: The unit of measurement for sampleSizeValue (days).3) Ocurrencias_colLong_ext: Comprises the total of 1,946 occurrence records of biological specimens collected in the 50 sampling sites over all sampling periods, primarily focusing on taxonomic classifications and their corresponding identifications. Each record is uniquely identified by an occurenceID, ensuring traceability and reproducibility of biological observations. There is also detailed taxonomic information, structured hierarchically across multiple levels, including kingdom, phylum, class, order, family, genus, and species. Some records also contain subfamily and tribe classifications, although certain taxonomic levels may have missing values.To enhance data provenance and reliability, each occurrence is linked to a data source (dataSourceId, dataSourceTitle), referencing authoritative taxonomic databases such as the Catalogue of Life and the Encyclopedia of Life (EOL). Additionally, the dataset includes an identificationQualifier field to indicate taxonomic uncertainty or provisional identifications. Biological observations are further characterized by individualCount, representing the number of individuals recorded per occurrence. The dataset also preserves the original taxonomic identification in the verbatimIdentification field, alongside an alternative version of the original identification label (verbatimIdentification2).4) Environment_ext: This dataset comprises 900 environmental measurement records, each uniquely identified by a measurementID and linked to a parentEventID, representing multiple environmental variables recorded within this sampling event. The dataset systematically documents key environmental conditions, including climatic factors, topographic features, vegetation structure, and species richness, facilitating ecological and biodiversity assessments.Each record includes a measurementType, specifying the environmental variable measured, a corresponding measurementValue, and its measurementUnit. Additionally, the dataset retains the original terminology for each environmental variable in the measurementTypeOriginal field, ensuring consistency with external datasets and methodological transparency.Climatic Variables:Average mean daily temperature (°C) (Abbreviated as TMEAN): The overall daily mean temperature across the sampling period.Average minimum daily temperature (°C) (Abbreviated as TMIN): The lowest recorded daily temperature.Average maximum daily temperature (°C) (Abbreviated as TMAX): The highest recorded daily temperature.Average daily temperature range (°C) (Abbreviated as AMPLD): The difference between maximum and minimum daily temperatures.Mean annual precipitation (mm) (Abbreviated as MAP): The average total annual precipitation at the sampling site.Topographic Features:Elevation (m.a.s.l.) (Abbreviated as ALT): The altitude above sea level at which the measurement was taken.Slope (degrees) (Abbreviated as SLP): The angle of the terrain at the sampling site, affecting water runoff and soil stability.Vegetation Structure and Soil Cover:Canopy cover (%) (Abbreviated as TREECOV): The proportion of the sky obscured by vegetation, measured using a spherical densiometer. This metric reflects the extent of overhead foliage and is an important indicator of forest structure and light availability at the understory level.Shrub cover (%) (Abbreviated as SC): The percentage of the ground covered by shrubs, as visually estimated.Herb cover (%) (Abbreviated as HC): The percentage of the ground covered by herbaceous plants.Bare soil (%) (Abbreviated as BS): The proportion of the ground surface without vegetation or litter.Dry litter biomass (g/m²) (Abbreviated as DLB): The weight of dry organic material accumulated on the floor.Plant Species Richness Metrics:Tree species richness (count) (Abbreviated as TSR): The number of tree species recorded at the sampling site.Shrub species richness (count) (Abbreviated as SSR): The number of shrub species observed.Herb species richness (count) (Abbreviated as HSR): The number of herbaceous plant species recorded.Plant species richness (count) (Abbreviated as PSR): The total count of plant species, including trees, shrubs, and herbs.Exotic plant species richness (count) (Abbreviated as EPSR): The number of non-native plant species.Anthropogenic Impact Indicator:Cattle faecal pats (Abbreviated as CFP): The number of cattle faecal pats counted at each sampling plot, used as an indicator of grazing pressure. This dataset was generated as part of a project funded by the Agencia Nacional de Promoción Científica y Tecnológica (Agencia-Foncyt) under grant PICT 2002 Nº 01-11826, titled "Patrones espaciales de variación en la diversidad de insectos en la transición subantártica-patagónica: efectos altitudinales y longitudinales." Additional funding was provided by the British Ecological Society through a Small Ecological Project Grant (SEPGNº 2243ª) for the project "Longitudinal patterns of variation in the richness and abundance of beetle species in the transition zone between the Subantarctic and Patagonian biogeographic provinces". asNeeded Victoria Werenkraut Instituto de Investigaciones en Biodiversidad y Medioambiente - INIBIOMA - (CONICET - Universidad Nacional del Comahue)

Bariloche Rio Negro 8400 AR

werenkraut@comahue-conicet.gob.ar Adriana Ruggiero Instituto de Investigaciones en Biodiversidad y Medioambiente - INIBIOMA - (CONICET - Universidad Nacional del Comahue)

Bariloche Rio Negro 8400 AR

ruggieroa@comahue-conicet.gob.ar The geographical location of each sampling plot was recorded in the field using a global positioning system (GPS). The dataset includes the decimal coordinates of each data point, referenced to the WGS84 datum. To associate the decimal coordinates of the sampling plots with political and administrative divisions at the sub-national level (provinces, departments, and municipalities or localities) within the study area, we used version 1.0 of the GADM database of global administrative boundaries, downloaded in March 2009. Beetle sampling was conducted at each plot at three key points during the plant growing season: the beginning (November 2004), middle (January 2005, 2006), and end (March 2005, 2006), ensuring coverage of the main period of beetle activity. To estimate beetle abundance at each of the 50 plots, we recorded the number of individuals captured per pitfall trap at each site and sampling event. The occurrence dataset includes the scientific names from our original database, verified against global biodiversity data sources using the Global Names Verifier (https://verifier.globalnames.org/), ensuring taxonomic accuracy. A detailed description of methods used to measure environmental variables at each sampling plot is given in Ruggiero et al. (2009). The study was conducted on a 150 x150 km area representative of the Subantarctic-Patagonian transition, in northwestern Patagonia, on the eastern slope of the Andes in Argentina, close to the border with Chile approximately between 39°78'S and 41°45'S latitude and 70°37'W and 71.88°W Epigaeic beetles were collected using a total of 450 plastic pitfall traps (9 cm in diameter, 12 cm in depth), arranged in 50 grid plots (100 m² each), with nine traps per plot. These plots were spaced approximately 15 km apart along five longitudinal (east-west) transects, which were established across the forest-steppe biogeographic transition zone. The traps were filled with 40% diluted propylene glycol and a drop of soap. They became operative immediately upon installation and remained open for seven days during three sampling periods in the southern spring and summer seasons (November 2004, and January, March 2005–2006). Data on temperature at ground level, vegetation cover, plant species richness and soil conditions were also collected to provide an environmental characterization of each sampling plot, as detailed explained in Ruggiero et al. (2009). Adriana Ruggiero xRhlUHgAAAAJ&hl=es&oi=ao principalInvestigator Alejandro G. Farji-Brener XCH4AZwAAAAJ principalInvestigator Cecilia Ezcurra h1QFJQcAAAAJ principalInvestigator Paula Sackmann contentProvider Karina Speziale contentProvider Victoria Werenkraut originator Biodiversity patterns are influenced by environmental gradients associated with climatic and vegetational changes. In combination with physiographic barriers such as rivers and mountains, these environmental changes promote taxonomic differentiation and affect species distribution and often define transition zones between biogeographical units. The conservation of these transitional areas is a priority, as they may facilitate adaptation to climate and anthropogenic changes. The project proposed to study how species richness, distribution, abundance, and body size of insects vary along longitudinal and altitudinal gradients in the transition between the subantarctic forests and Patagonian steppes in northwestern Patagonia (Argentina). This is a region with one of the most pronounced environmental changes in the world, where precipitation varies from 500 mm to 3,000 mm over just 100 km. The influence of climate, topography, and resource availability on biodiversity patterns were analyzed. Although insects represent the largest share of global biodiversity, most studies on spatial diversity patterns have focused on birds and mammals. Furthermore, biodiversity analyses in insects have been scarce in the Southern Hemisphere. Beetles and ants are ideal groups for study due to their environmental sensitivity and key ecological roles in ecosystems. However, knowledge about insect fauna in this region remains insufficient for designing effective conservation strategies. The present study 1) provided data of the taxonomic and functional diversity of beetles and ants in the transition zone between forest and steppe, documenting species richness, distribution, abundance, and body size at local and regional scales; 2) applied geospatial tools (GPS and GIS) to map species distributions and correlate them with biological attributes. 3) Analyzed altitudinal and latitudinal variation in biodiversity and ecological traits of species. 4) Evaluated ecological hypotheses regarding the climatic, vegetational and soil factors influencing biodiversity along these gradients. Agencia-FONCyT (PICT2002 Nº 01-11826) Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación (Agencia - FONCYT) PICT2002 Nº 01-11826 http://www.agencia.mincyt.gob.ar/upload/res.117-03-Financiados-Pict2002-cat-II-financiados.pdf The study area was located in northwestern Patagonia, Argentina, in the western region of the Río Negro and Neuquén provinces, approximately between 39°30'S and 41°30'S latitude and 70°30'W and 72°W longitude. The western portion of the study area includes a significant part of the northern Patagonian Andes, characterized by high mountain ranges and glaciers. The terrain gradually decreases in elevation toward the east, transitioning into Patagonian plateaus that barely reach 1,000 meters. The western region was heavily impacted by Quaternary glaciations, resulting in numerous glacial valleys, lakes, and moraines. Several key tourist centers are located within this area, including the cities of Junín de los Andes, San Martín de los Andes, Villa La Angostura, and San Carlos de Bariloche, which are among the most important tourism hubs in northern Argentine Patagonia. The region has a temperate climate, with average July temperatures below 4°C and average January temperatures below 18°C. Rainfall and snowfall occur primarily in winter, while summers are relatively dry, and frost can occur throughout the year. Precipitation decreases significantly from west to east, ranging from more than 3,000 mm in the mountains and lakes near the Chilean border to around 300 mm on the Patagonian plateau. This precipitation gradient drives distinct vegetation changes, transitioning from evergreen rainforest in the west, to deciduous mesic forests, xeric shrublands in the ecotone, and shrub-grass steppe in the east. The forest region is classified within the Subantarctic Biogeographic Subregion and is generally dominated by tree species of the genus Nothofagus. Towards the west rainy portion of the study area, the forests are dominated by evergreen species such as Nothofagus dombeyi (coihue) and conifers like Fitzroya cupressoides (alerce). These forests are replaced towards the east by mesic forests characterized by deciduous species including Nothofagus antarctica (ñire), Nothofagus nervosa (raulí), and Nothofagus obliqua (roble pellín), along with conifers such as Araucaria araucana (monkey puzzle tree) and Austrocedrus chilensis (cypress). At the easternmost portion of the study area the Patagonian biogeographic subregion is found, characterized by xerophytic grasslands, primarily composed of species from the genera Festuca, Stipa, and Poa, along with shrubs from the genera Mulinum, Senecio, and Adesmia. At the highest altitudes, mountains also have high-altitude steppes lacking trees. Epigaeic beetles were collected using a total of 450 plastic pitfall traps (9 cm in diameter, 12 cm in depth), arranged in 50 grid plots (100 m² each), with nine traps per plot. These plots were spaced approximately 15 km apart along five longitudinal (east-west) transects, which were established across the forest-steppe biogeographic transition zone Adriana Ruggiero xRhlUHgAAAAJ&hl=es&oi=ao principalInvestigator 2025-02-21T20:02:48.601+00:00 dataset Sackmann P, Elgueta M, Flores G E, Kun M, Ocampo F, Posadas P, Roig-Juñent S, Werenkraut V, Ruggiero A (2025). Dataset from a subantarctic forests - Patagonian steppes longitudinal transition in northwestern Patagonia (Argentina): Beetles. Version 1.2. Training Organization. Samplingevent dataset. https://training-ipt-c.gbif.org/resource?r=nwpatagonia_forest-steppe_transition&v=1.2 Ruggiero, A., Sackmann, P., Farji-Brener, A. G., & Kun, M. (2009). Beetle abundance–environment relationships at the Subantarctic–Patagonian transition zone. Insect Conservation and Diversity, 2(2), 81-92. Sackmann, P., & Flores, G. E. (2009). Temporal and spatial patterns of tenebrionid beetle diversity in NW Patagonia, Argentina. Journal of Arid Environments, 73(12), 1095-1102. https://ipt.mincyt.gob.ar/resource?id=transect_bettles/v1.2.xml