8 research outputs found
Sclerophyllous Forest Tree Growth Under the Influence of a Historic Megadrought in the Mediterranean Ecoregion of Chile
The Mediterranean-type Ecosystems of Central Chile is one of the most threatened regions in South America by global change, particularly evidenced by the historical megadrought that has occurred in central Chile since 2010. The sclerophyllous forest stands out, whose history and relationship with drought conditions has been little studied. Cryptocarya alba and Beilschmiedia miersii (Lauraceae), two large endemic trees, represent an opportunity to analyze the incidence of intense droughts in the growth of sclerophyllous forests by analyzing their tree rings. Here, we considered > 400 trees from nineteen populations of C. alba and B. miersii growing across a latitudinal gradient (32°â35° S). To study the influence of local and large-scale climatic variability on tree growth, we first grouped the sites by species and explored the relationships between tree-growth patterns of C. alba and B. miersii with temperature, precipitation, and climate water deficit (CWD). Second, we performed Principal Component Analysis to detect common modes of variability and to explore relationships between growth patterns and their relationship to Palmer Drought Severity Index (PDSI), ENSO and SAM indices. We detected a breaking point as of 2002 at regional level, where a persistent and pronounced decrease in tree growth occurred, mainly influenced by the increase in CWD and the decrease in winter-spring rainfall. In addition, a positive (negative) relationship was showed between PC1 growth-PDSI and PC1 growth-ENSO (growth-SAM), that is, growth increases (decreases) in the same direction as PDSI and ENSO (SAM). Despite the fact that sclerophyllous populations are highly resistant to drought events, we suggest that the sclerophyllous populations studied here experienced a generalized growth decline, and possibly the natural dynamics of their forests have been altered, mainly due to the accumulating effects of the unprecedented drought since 2010.Fil: Venegas Gonzalez, Alejandro. Universidad de Oâhiggins; Chile. Universidad Mayor; ChileFil: Muñoz, Ariel A.. Pontificia Universidad CatĂłlica de ValparaĂso; ChileFil: Carpintero Gibson, S.. Universidad Mayor.; ChileFil: Schneider, I.. Pontificia Universidad CatĂłlica de ValparaĂso; ChileFil: Gipolou Zuñiga, T.. Universidad Austral de Chile; ChileFil: Aguilera Betti, I.. Pontificia Universidad CatĂłlica de ValparaĂso; ChileFil: Roig Junent, Fidel Alejandro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales; Argentin
The First Millennium-Age Araucaria Araucana in Patagonia
This item is part of the Tree-Ring Research (formerly Tree-Ring Bulletin) archive. For more information about this peer-reviewed scholarly journal, please email the Editor of Tree-Ring Research at [email protected]
Dendrohydrology and water resources management in south-central Chile: lessons from the RĂo Imperial streamflow reconstruction
Streamflow in south-central Chile (SCC, ââŒââŻ37â42°âŻS) is vital
for agriculture, forestry production, hydroelectricity, and human
consumption. Recent drought episodes have generated hydrological deficits
with damaging effects on these activities. This region is projected to
undergo major reductions in water availability, concomitant with projected
increases in water demand. However, the lack of long-term records hampers the
development of accurate estimations of natural variability and trends. In
order to provide more information on long-term streamflow variability and
trends in SCC, here we report findings of an analysis of instrumental records
and a tree-ring reconstruction of the summer streamflow of the RĂo Imperial
(ââŒââŻ37°âŻ40âČâŻSâ38°âŻ50âČâŻS). This is the first
reconstruction in Chile targeted at this season. Results from the
instrumental streamflow record (ââŒââŻ1940 onwards) indicated that the
hydrological regime is fundamentally pluvial with a small snowmelt
contribution during spring, and evidenced a decreasing trend, both for the
summer and the full annual record. The reconstruction showed that streamflow
below the average characterized the post-1980 period, with more frequent, but
not more intense, drought episodes. We additionally found that the recent
positive phase of the Southern Annular Mode has significantly influenced
streamflow. These findings agree with previous studies, suggesting a robust
regional signal and a shift to a new hydrological scenario. In this paper, we
also discuss implications of these results for water managers and
stakeholders; we provide rationale and examples that support the need for the
incorporation of tree-ring reconstructions into water resources management
GIMMS NDVI time series reveal the extent, duration, and intensity of âblooming desertâ events in the hyper-arid Atacama Desert, Northern Chile
The âblooming desertâ, or the explosive development and flowering of ephemeral herbaceous and some woody desert species during years with abnormally high accumulated rainfall, is a spectacular biological phenomenon of the hyper-arid Atacama Desert (northern Chile) attracting botanists, ecologists, geo-scientists, and the general public from all over the world. However, the number of âblooming desertsâ, their geographical distribution and spatio-temporal patterns have not been quantitatively assessed to date. Here, we used NDVI data from the Global Inventory Modeling and Mapping Studies (GIMMS) project to reconstruct the annual land surface phenology (LSP) of the Atacama Desert using a non-parametric statistical approach. From the reconstructed LSP, we detected the âblooming desertsâ as positive NDVI anomalies and assessed three dimensions of the events: their temporal extent, intensity of âgreeningâ and spatial extent. We identified 13 âblooming desertsâ between 1
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A Cross-Cutting Approach for Relating Anthropocene, Environmental Injustice and Sacrifice Zones
The Anthropocene is an uneven phenomenon. Accelerated shifts in the functioning of the Earth System are mainly driven by the production and consumption of wealthy economies. Social, environmental and health costs of such industrialization, however, bear on low-income communities inhabiting severely degraded territories by polluting activities (i.e., sacrifice zones). How global, national and local socio-economic and governance processes have interacted in perpetuating socio-environmental inequalities in these territories has been rarely explored. Here, we develop an historical quantitative approach integrating a novel chemostratigraphic record, data on policy making, and socio-economic trends to evaluate the feedback relationship between environmental injustice and Anthropocene in sacrifice zones. We specifically outline a case study for the Puchuncavà valley -one of the most emblematic sacrifice zones from Chile-. We verify an ever-growing burden of heavy metals and metalloids over the past five decades paced by the staggering expansion of local industrial activities, which has ultimately been spurred by national and transnational market forces. Local poverty levels have declined concomitantly, but this path toward social equality is marginal as costs of pollution have grown through time. Indeed, national and international pollution control actions appear insufficient in mitigating the cumulative impact brought by highly toxic elements. Thus, our sub-decadal reconstruction for pollution trends over the past 136 years from a sediment record, emerges as a science-based tool for informing the discussion on Anthropocene governance. Furthermore, it helps to advance in the assessment of environmental inequality in societal models that prioritize economic growth to the detriment of socio-environmental security. © 2022 The Authors. Earth's Future published by Wiley Periodicals LLC on behalf of American Geophysical Union.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Dendrochronological Study of the Xeric and Mesic Araucaria araucana Forests of Northern Patagonia: Implications for Ecology and Conservation
The identification of the forest structure could give insights of the processes that determine certain aspects of the population dynamics over time. To address this concern in the Araucaria araucana forests of northwestern Patagonia in Argentina, 14 forest stands distributed along a strong precipitation gradient were analyzed. A suite of components of the forest structure were considered in order to determine (1) the relationship between climate and tree growth variability, (2) the age structure of each study site by defining age classes through the tree-ring analysis, (3) the relationship between tree age, tree height, and stem diameter, and (4) sex ratio. Xeric forests were affected significantly and negatively by the temperature of the current growing season, while mesic forests were more affected during winter months. Precipitation showed a positive effect on growth at the beginning of the growing season in all forests. Age distribution in the xeric and mesic environments showed a preponderance of trees between 51 and 300, and 51 and 250 years old, respectively. Broadly, male and female trees were more abundant in xeric and mesic forests, respectively. The tree age-diameter and tree height-diameter relationships were significantly positive in both mesic and xeric environments. Through these elements, some aspects of the A. araucana trees and forests in their natural distribution area were revealed, which consolidate a better understanding of the ecology and dynamics of these endemic forests and provide tools for designing proper conservation strategies.Fil: Hadad, MartĂn Ariel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas FĂsicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Arco Molina, Julieta Gabriela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales; ArgentinaFil: Roig Junent, Fidel Alejandro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales; Argentina. Universidad Mayor; Chile. Universidade de Sao Paulo; Brasi