Lake fluctuations, plant productivity, and long term variability in high elevation tropical andean ecosystems

Despite the large scientific and conservation value of tropical very high elevation Andean ecosystems (above 4500 masl) little is known about environmental trends and ranges of variability. We combined satellite image analyses and dendrochronological methods to quantify changes in water balance and plant productivity of these ecosystems in northern Argentina and southern Bolivia through assessments of lake level fluctuation combined with instrumental climatic records at lower elevation; and to assess the relationships between water balance and two indices of plant productivity: tree ring width of the treelet Polylepis tarapacana and seasonal patterns of vegetation "greenness" (EVI) derived from satellite images. Between 1986 and 2007, inter-annual lake fluctuations were positively correlated with regional precipitation and de Martonne?s aridity index between, showing a decreasing trend during the period. Changes in lake size were correlated with radial growth of P. tarapacana, and with MODIS-derived annual EVI between 2001-2010; thus indicating that water balance has a significant effect on ecosystem functioning. A long term tree ring chronology indicated that recent trends of decreasing plant productivity and lakes size are still within the range of variability of the past 400 years, but such ranges may be exceeded in the coming decades if the trend persists.Fil: Carilla, Julieta. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Paolini, Leonardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Morales, Mariano Santos. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

Side effects of green technologies: the potential environmental costs of Lithium mining on high elevation Andean wetlands in the context of climate change

Lithium-based batteries are the key component of booming green technologies, including hybrid electric, plug-in hybrid electric and battery electric vehicles. Nearly 80% of the global lithium resources are located in the subtropical “Puna” highlands of Argentina, Bolivia and Chile. In these arid ecosystems, most biodiversity is related to wetlands: this highly valuable biodiversity includes the emblematic native camelids, flamingos, and a rich variety of endemic plants, and other animals. Climatic trends during the past decades, and future climate models suggest persistent drying tendencies. As other mining operations, lithium exploitations of salty flats require relatively large amounts of water. We discuss the research questions and priorities to preserve these valuable ecosystems in the context of growing potential conflicts for the use of water.Fil: Izquierdo, Andrea Elisa. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carilla, Julieta. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Casagranda, Elvira. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentin

Permafrost creeping, inventory and verification in the upper basin of Bermejo river

Los glaciares de escombros son reservorios de agua dulce congelados en las altas montañas del mundo y son claves para la vida de la población local y sus economías. La presencia de glaciares de escombros es usada comúnmente como indicador directo de condiciones de permafrost de montaña. En las cabeceras de la alta cuenca del río Bermejo se han localizado glaciares de escombros, mediante técnicas de interpretación visual en distintos tipos de imágenes satelitales e identificación en terreno de las geoformas. Esta región de los Andes Áridos es particularmente vulnerable al calentamiento global: por la fragilidad de los ecosistemas y por la alta vulnerabilidad de la población. Este estudio tiene por objeto proveer observaciones preliminares de la distribución de los glaciares de escombros y de las geoformas periglaciales asociadas a nivel regional. Además, es un aporte al conocimiento de la hidrología de la región ya que se ha generado información de base para la adaptación a los procesos de cambio que sobrevendrán. Los resultados, también ponen en evidencia las ventajas de usar técnicas geomáticas en áreas de accesibilidad dificultosa, con reducción de costos y tiempo de trabajo.Rock glaciers are frozen water reservoirs in the mountain areas of the world. Water resources are important for the local habitants and economies. The presence of rock glaciers is commonly used as a direct indicator of mountain permafrost conditions. In the headwaters of the upper basin of Bermejo river rock glaciers have been located using visual interpretation techniques in different types of satellite imagery and field identification. Ecosystems and their population in the Dry Andes are particularly fragile to any change caused by global warming. This study aims to provide preliminary observations of rock glaciers and associated periglacial geoforms. This is a contribution to the knowledge of the hydrology of the region to generate baseline information for adapting to possible future changes. Results put in evidence the advantages of using geomatics tools in areas of difficult accessibility, with reduced costs and work time.Fil: Ahumada, Ana Lia. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ibáñez Palacios, Gloria Patricia. Fundación Miguel Lillo; ArgentinaFil: Toledo, Mario A.. Fundación Miguel Lillo; ArgentinaFil: Carilla, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Páez, Silvia Verónica. Fundación Miguel Lillo; Argentin

Spatial, Temporal and Ecological Patterns of Peri-Urban Forest Transitions: An Example From Subtropical Argentina

Most studies on forest transition (FT) have focused on temporal patterns of forest cover across whole countries or regions, without much consideration of the local spatio-temporal heterogeneity or the species composition of new forests. We hypothesize that peri-urban forest transitions are driven by processes associated with urban-based economies and functioning, which define spatial characteristics of new forests. We analyzed the patterns of peri-urban forest expansion detected during the past three decades in the Lules watershed, a montane area of ca. 100,000 ha around San Miguel de Tucumán (SMT), an urban center of ca. one million inhabitants in the Andean foothills of subtropical Argentina. New forests (4,600 ha) were observed through the watershed, but they were more frequent at short distances (1–15 km) from the urban and second home residential areas. New forests nearby SMT are characterized by higher plant diversity largely due to a higher proportion of exotic species. In some cases, these exotic species dominated new forests diminishing stand-level biodiversity. Second-home residential areas, a byproduct of the urban centers in intermontane valleys, replicate the spatial patterns of exotic-dominated forest transition observed around SMT. We argue that peri-urban FT provides an early characterization of the future patterns of spontaneous forest transition with increased presence of globalized species which may locally increase species richness. We use the case study to discuss emerging research lines and to emphasize the importance of urban-centered land use policies (e.g., associated to urban-based uses such as recreation or watershed conservation) as key targets for promoting new forests more beneficial for future generations.Fil: Jiménez, Yohana Gisell. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Ceballos, Sergio Javier. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Aráoz, Ezequiel. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Blundo, Cecilia Mabel. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Carilla, Julieta. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Malizia, Agustina. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentin

Hydroclimate and vegetation variability of high Andean ecosystems

Mountain ecosystems are sensitive to climate fluctuations; however, the scarcity of instrumental data makes necessary the use of complementary information to study the effect of climate change on these systems. Remote sensing permits studying the dynamics of vegetation productivity and wetlands in response to climate variability at different scales. In this study we identified the main climate variables that control vegetation dynamics and water balance in Cumbres Calchaquíes, NW Argentina. For this, we built annual time series from 1986 to 2019 of Soil Adjusted Vegetation Index (SAVI, to quantify spare vegetation productivity), lake area, and snow-ice cover of peatlands, as indicators of mountain productivity and hydrology. We used a decompose function to explore trend, seasonality and random signal of the three-time series, and explored for significant changes in the mean value of consecutive periods. We used correlational analysis to explore their associations with climate records at local, regional, and global scales. The results showed that, SAVI and hydrological indicators presented different fluctuation patterns more pronounced since 2012, when they showed divergent trends with increasing SAVI and decreasing lake area and snow-ice cover. The three indicators responded differently to climate; SAVI increased in warmer years and lake area reflected the water balance of previous years. Snow-ice cover of peatlands was highly correlated with lake area. La Niña had a positive effect on lake area and snow-ice cover and a negative on SAVI, while El Niño had a negative effect on SAVI. Fluctuations of lake areas were synchronized with lake area in the nearby Argentinian puna, suggesting that climate signals have regional extent. The information provided by the three hydroclimate indicators is complementary and reflects different climate components and processes; biological processes (SAVI), physical processes (snow ice cover) and their combination (lake area). This study provides a systematic accessible replicable tool for mountain eco-hydrology long-term monitoring

Geomorphological observations on rock glaciers of the Tropical Andes of Argentina

La degradación del permafrost es uno de los factores cruciales de los quedepende la estabilidad de laderas en alta montaña y está fuertemente relacionada con las alteraciones y los cambios atmosféricos vinculados al cambio climático. La presencia de glaciares de escombros activos indica condiciones de permafrost de montaña. Constituyen reservorios hídricos congelados. Son capaces de desplazar grandes volúmenes de detritos y ante las actuales modificaciones climáticas el proceso puede acelerarse. Estos sedimentos potencialmenteinestables, que se ubican en la zona de iniciación de flujos de detrito, requieren detección, mapeo como etapa preliminar y posterior seguimiento para la prevención de desastres naturales. En las cabeceras de la Alta cuenca del río Bermejo, sierra de Santa Victoria, entre 22º08? y los 23º00? de latitud Sur (trópico de Capricornio) y entre 65º y 65º30? de longitud Oeste, se Inventariaron glaciares de escombros utilizando imágenes satelitales (Aster, Spot y CBERS2), inspección visual con Google Earth, con comprobación enterreno en 27 geoformas. En algunos glaciares de escombros se detectaron y describieron rasgos de degradación. Estos indicadores son objeto de atención especial en este trabajo. Esta región intertropical de los Andes Áridos es vulnerable al calentamiento global, por la fragilidad de los ecosistemas y la alta vulnerabilidad de la población. Los recursos hídricos y la estabilidad de las laderas son cruciales para la población local y sus economías. Se aportaal conocimiento y estado de la criósfera regional para promover la adaptación a los cambios que ocurrirán.Permafrost degradation is one of the crucial factors for the stability of slopes in high mountains and is strongly related to disturbances and atmospheric changes linked to climate change. The presence of active rock glaciers indicates mountain permafrost conditions. These landforms are frozen water reservoirs. They are able to move large volumes of debris. Current climatic changes can accelerate this process. These potentially unstable sediments, which are located in the initiation of debris flows, require detection, mapping and preliminary stage and monitoring for the prevention of natural hazards. In the headwaters of the Upper Bermejo river, Sierra de Santa Victoria, between 22º08' and 23º00' south (Tropic of Capricorn) and between 65º and 65º30' west, rock glaciers were inventoried using satellite imagery (Aster, Spot and CBERS2), visual inspection with Google Ear th, field-tested in 27 landforms. In some rock glaciers features of degradation were detected and described. These indicators are subject of special attention in this paper. This inter tropical Dry Andes region is particularly vulnerable to global warming, by the fragility of ecosystems and the high vulnerability of the population. Water resources and slope stability are crucial for local population and its economies. This work provides the knowledge and state of the cryosphere regional baseline information to promote adaptation to changes.Fil: Ahumada, Ana Lia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Fundación Miguel Lillo; ArgentinaFil: Ibañez Palacios, G.. Fundación Miguel Lillo; ArgentinaFil: Carilla, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; ArgentinaFil: Toledo, Mario Arnaldo. Fundación Miguel Lillo; ArgentinaFil: Paez, S. V.. Fundación Miguel Lillo; Argentin

Compositional shifts of alpine plant communities across the high Andes.

Aim: Climate change is transforming mountain summit plant communities worldwide, but we know little about such changes in the High Andes. Understanding large-scale patterns of vegetation changes across the Andes, and the factors driving these changes, is fundamental to predicting the effects of global warming. We assessed trends in vegetation cover, species richness (SR) and community-level thermal niches (CTN) and tested whether they are explained by summits' climatic conditions and soil temperature trends. Location: High Andes. Time period: Between 2011/2012 and 2017/2019. Major taxa studied: Vascular plants. Methods: Using permanent vegetation plots placed on 45 mountain summits and soil temperature loggers situated along a ~6800 km N-S gradient, we measured species and their relative percentage cover and estimated CTN in two surveys (intervals between 5 and 8 years). We then estimated the annual rate of changes for the three variables and used generalized linear models to assess their relationship with annual precipitation, the minimum air temperatures of each summit and rates of change in the locally recorded soil temperatures. Results: Over time, there was an average loss of vegetation cover (mean = −0.26%/ yr), and a gain in SR across summits (mean = 0.38 species m2/yr), but most summits had significant increases in SR and vegetation cover. Changes in SR were positively related to minimum air temperature and soil temperature rate of change. Most plant communities experienced shifts in their composition by including greater abundances of species with broader thermal niches and higher optima. However, the measured changes in soil temperature did not explain the observed changes in CTN. Main conclusions: High Andean vegetation is changing in cover and SR and is shifting towards species with wider thermal niche breadths. The weak relationship with soil temperature trends could have resulted from the short study period that only marginally captures changes in vegetation through time.EEA Santa CruzFil: Cuesta, F. Universidad de las Américas. Grupo de Investigación en Biodiversidad Medio Ambiente y Salud – BIOMAS; Ecuador.Fil: Carilla, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Carilla, Julieta. Universidad Nacional de Tucumán. Instituto de Ecología Regional; Argentina.Fil: Llambí, L.D. Universidad de Los Andes. Instituto de Ciencias Ambientales y Ecológicas; Venezuela.Fil: Llambí, L.D. Consorcio para el Desarrollo Sostenible de la Ecorregión Andina (CONDESAN); Perú.Fil: Muriel, P. Pontificia Universidad Católica del Ecuador. Escuela de Ciencias Biológicas Laboratorio de Ecofisiología; Ecuador.Fil: Lencinas, María Vanessa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas (CADIC); Argentina.Fil: Meneses, R. I. Universidad Católica del Norte. Instituto de Investigaciones Arqueológicas y Museo; Chile.Fil: Feeley, K. J. University of Miami. Biology Department. Coral Gables; Estados UnidosFil: Pauli, H. Austrian Academy of Sciences. Institute for Interdisciplinary Mountain Research; Austria.Fil: Pauli, H. University of Natural Resources and Life Sciences. Department of Integrative Biology and Biodiversity Research; Austria.Fil: Aguirre, N. Universidad Nacional de Loja. Carrera de Ingeniería Forestal. Centro de Investigaciones Tropicales del Ambiente y Biodiversidad (CITAB); Ecuador.Fil: Beck, S. Museo Nacional de Historia Natural - Instituto de Ecología (UMSA). Herbario Nacional de Bolivia; Bolivia.Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Tovar, C. Royal Botanical Gardens Kew. Jodrell Laboratory; Reino Unid

Plant dispersal strategies of high tropical alpine communities across the Andes

Dispersal is a key ecological process that influences plant community assembly. Therefore, understanding whether dispersal strategies are associated with climate is of utmost importance, particularly in areas greatly exposed to climate change. We examined alpine plant communities located in the mountain summits of the tropical Andes across a 4,000-km latitudinal gradient. We investigated species dispersal strategies and tested their association with climatic conditions and their evolutionary history. We used dispersal-related traits (dispersal mode and growth form) to characterize dispersal strategies for 486 species recorded on 49 mountain summits. Then we analysed the phylogenetic signal of traits and investigated the association between dispersal traits, phylogeny, climate and space using structural equation modelling and fourth-corner analysis together with RLQ ordination. A median of 36% species in the communities was anemochorous (wind-dispersed) and herbaceous. This dispersal strategy was followed by the barochory-herb combination (herbaceous with unspecialized seeds, dispersed by gravity) with a median of 26.3% species in the communities. The latter strategy was common among species with distributions restricted to alpine environments. While trait states were phylogenetically conserved, they were significantly associated with a temperature gradient. Low minimum air temperatures, found at higher latitudes/elevations, were correlated with the prevalence of barochory and the herb growth form, traits that are common among Caryophyllales, Brassicaceae and Poaceae. Milder temperatures, found at lower latitudes/elevations, were associated with endozoochorous, shrub species mostly from the Ericaceae family. Anemochorous species were found all along the temperature gradient, possibly due to the success of anemochorous Compositae species in alpine regions. We also found that trait state dominance was more associated with the climatic conditions of the summit than with community phylogenetic structure. Although the evolutionary history of the tropical Andean flora has also shaped dispersal strategies, our results suggest that the environment had a more predominant role. Synthesis. We showed that dispersal-related traits are strongly associated with a gradient of minimum air temperatures in the Andes. Global warming may weaken this key filter at tropical alpine summits, potentially altering community dispersal strategies in this region and thus, plant community structure and composition.Fil: Tovar, Carolina. Royal Botanic Gardens; Reino UnidoFil: Melcher, Inga. University of Amsterdam; Países BajosFil: Kusumoto, Buntarou. Royal Botanic Gardens; Reino Unido. University Of The Ryukyus, Okinawa; JapónFil: Cuesta, Francisco. Universidad de Las Américas.; EcuadorFil: Cleef, Antoine. University of Amsterdam; Países BajosFil: Meneses, Rosa Isela. Universidad Católica del Norte; ChileFil: Halloy, Stephan. Ministry For Primary Industries; Nueva ZelandaFil: Llambi, Luis Daniel. Universidad de Los Andes; VenezuelaFil: Beck, Stephan G.. Universidad Mayor de San Andrés; BoliviaFil: Muriel, Priscilla. Pontificia Universidad Católica del Ecuador; EcuadorFil: Jaramillo, Ricardo Luis. Pontificia Universidad Católica del Ecuador; EcuadorFil: Jacome, Jorge. Pontificia Universidad Javeriana; ColombiaFil: Carilla, Julieta. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentin

Understanding climate change impacts on biome and plant distributions in the Andes: Challenges and opportunities

Aim: Climate change is expected to impact mountain biodiversity by shifting species ranges and the biomes they shape. The extent and regional variation in these impacts are still poorly understood, particularly in the highly biodiverse Andes. Regional syntheses of climate change impacts on vegetation are pivotal to identify and guide research priorities. Here we review current data, knowledge and uncertainties in past, present and future climate change impacts on vegetation in the Andes. Location: Andes. Taxon: Plants. Methods: We (i) conducted a literature review on Andean vegetation responses to past and contemporary climatic change, (ii) analysed future climate projections for different elevations and slope orientations at 19 Andean locations using an ensemble of model outputs from the Coupled Model Intercomparison Project 5, and (iii) calculated changes in the suitable climate envelope area of Andean biomes and compared these results to studies that used species distribution models. Results: Future climatic changes (2040–2070) are projected to be stronger at high-elevation areas in the tropical Andes (up to 4°C under RCP 8.5), while in the temperate Andes temperature increases are projected to be up to 2°C. Under this worst-case scenario, temperate deciduous forests and the grasslands/steppes from the Central and Southern Andes are predicted to show the greatest losses of suitable climatic space (30% and 17%–23%, respectively). The high vulnerability of these biomes contrasts with the low attention from researchers modelling Andean species distributions. Critical knowledge gaps include a lack of an Andean wide plant checklist, insufficient density of weather stations at high-elevation areas, a lack of high-resolution climatologies that accommodates the Andes' complex topography and climatic processes, insufficient data to model demographic and ecological processes, and low use of palaeo data for distribution modelling. Main conclusions: Climate change is likely to profoundly affect the extent and composition of Andean biomes. Temperate Andean biomes in particular are susceptible to substantial area contractions. There are, however, considerable challenges and uncertainties in modelling species and biome responses and a pressing need for a region-wide approach to address knowledge gaps and improve understanding and monitoring of climate change impacts in these globally important biomes.publishedVersio