Climatic fluctuations in the Central Region of Argentina in the last 1000 years

Cioccale, Marcela

doi:10.1016/s1040-6182(99)00021-x

Cited by 89 publications

(87 citation statements)

References 6 publications

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“…Again, this evidence is consistent with the modern-day hydroclimatic response to La Niña. However, geomorphological evidence presented by Carignano (1999), Cioccale (1999), and Iriondo (1999) suggests that the MCA in central Argentina was generally wet, a region often in phase with western North America, and dry during La Niña (HESE). Finally, at the southernmost tip of South America, the MCA is recorded in Patagonia as a dry period (Stine and Stine 1990;Stine 1994;Haberzettl et al 2005) and once again fits the footprint of persistent extratropical droughts in the modern day (HESE).…”

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confidence: 99%

North American Droughts of the Last Millennium from a Gridded Network of Tree-Ring Data

et al. 2007

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Drought is the most economically expensive recurring natural disaster to strike North America in modern times. Recently available gridded drought reconstructions have been developed for most of North America from a network of drought-sensitive tree-ring chronologies, many of which span the last 1000 yr. These reconstructions enable the authors to put the famous droughts of the instrumental record (i.e., the 1930s Dust Bowl and the 1950s Southwest droughts) into the context of 1000 yr of natural drought variability on the continent. We can now, with this remarkable new record, examine the severity, persistence, spatial signatures, and frequencies of drought variability over the past milllennium, and how these have changed with time.The gridded drought reconstructions reveal the existence of successive "megadroughts," unprecedented in persistence (20-40 yr), yet similar in year-to-year severity and spatial distribution to the major droughts experienced in today's North America. These megadroughts occurred during a 400-yr-long period in the early to middle second millennium A.D., with a climate varying as today's, but around a drier mean. The implication is that the mechanism forcing persistent drought in the West and the Plains in the instrumental era is analagous to that underlying the megadroughts of the medieval period. The leading spatial mode of drought variability in the recontructions resembles the North American ENSO pattern: widespread drought across the United States, centered on the Southwest, with a hint of the opposite phase in the Pacific Northwest.Recently, climate models forced by the observed history of tropical Pacific SSTs have been able to successfully simulate all of the major North American droughts of the last 150 yr. In each case, cool "La Niña-like" conditions in the tropical Pacific are consistent with North American drought. With ENSO showing a pronounced signal in the gridded drought recontructions of the last millennium, both in terms of its link to the leading spatial mode, and the leading time scales of drought variability (revealed by multitaper spectral analysis and wavelet analysis), it is postulated that, as for the modern day, the medieval megadroughts were forced by protracted La Niña-like tropical Pacific SSTs. Further evidence for this comes from the global hydroclimatic "footprint" of the medieval era revealed by existing paleoclimatic archives from the tropical Pacific and ENSO-sensitive tropical and extratropical land regions. In general, this global pattern matches that observed for modern-day persistent North American drought, whereby a La Niña-like tropical Pacific is accompanied by hemispheric, and in the midlatitudes, zonal, symmetry of hydroclimatic anomalies.

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confidence: 99%

North American Droughts of the Last Millennium from a Gridded Network of Tree-Ring Data

et al. 2007

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“…Además observamos que el patrón disyunto de la especie entre las sierras de Córdoba y San Luis estaría enmarcado por la existencia de una barrera climática y/o topográfica aunque la naturaleza de la misma queda pendiente de esclarecimiento. Estudios previos han sugerido que los patrones de distribución de las especies de la zona serrana podrían haber tomado su configuración actual durante el Cuaternario en el que las variaciones climáticas habrían sido determinantes (Kröhling & Carignano, 2014;Chiapella & Demaio, 2015), como ha sido reportado en varios estudios (Cioccale, 1999;Silva et al, 2011;Giorgis et al, 2015, entre otros). Los resultados encontrados para S. linearifolia sugieren una diversificación reciente de la especie, posiblemente asociada a procesos geológicos y climáticos recientes en la región.…”

Section: Discussionunclassified

Rango geográfico y estructura espacial de linajes genéticos en Sophora linearifolia (Fabaceae), un arbusto endémico de las sierras centrales de Argentina.

Alercia

Giorgis

Funes

et al. 2017

Bol. Soc. Argent. Bot.

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Summary: Geographical range and spatial structure of genetic lineages in Sophora linearifolia (Fabaceae), an endemic shrub of Central Argentina. A large number of endemic species occur in the Sierras of Córdoba and San Luis. A significant group of them shows a disjunct geographic distribution between these two mountain regions. Until the present study, there were none genetic studies that allow us to infer historical processes underlying this geographical pattern. For this purpose, we characterize the distribution area and phylogeographic patterns of Sophora linearifolia, across its geographic range which includes Sierras Chicas (SC) and Cumbres de Gaspar (CG) in Córdoba and in the southwestern area of Sierras of San Luis (SL). We compared the current with the predicted species area of distribution using ecological niche modelling analysis. We also analyzed genetic variability and spatial structure of the DNA chloroplast marker trnH-psbA, and reconstructed the genealogical relationships among the retrieved haplotypes. Current and the predicted distribution agreed in showing a climatic/topographic disjunction between Sierras of Cordoba and San Luis hills, although the current distribution presents a disjunction between SC and CG in Córdoba, not shown in the potential distribution map. We obtained eight haplotypes with restricted distribution and low levels of genetic differentiation that were grouped into four phylogroups: SC, CG and two in SL. Our results indicate that S. linearifolia presents low dispersal ability and it would have recently diversified, suggesting a neoendemic taxon.Key words: Chloroplastidial DNA, biogeography, disjunct, distribution, ecological niche modelling, phylogeography, neoendemic, Sierras Pampeanas.Resumen: Las sierras de Córdoba y San Luis albergan una gran riqueza de especies endémicas. Un grupo importante de ellas muestra una distribución disyunta entre ambas serranías. Hasta la actualidad no existían estudios genéticos que permitieran inferir procesos históricos asociados a este patrón. Con este propósito caracterizamos el área de distribución y el patrón filogeográfico de Sophora linearifolia, abarcando todo su rango geográfico que incluye las Sierras Chicas (SC) y las Cumbres de Gaspar (CG) en Córdoba y el suroeste de las Sierras de San Luis (SL). Contrastamos la distribución actual con la distribución predicha a partir del modelado del nicho ecológico. Analizamos el nivel de variabilidad genética, la estructuración espacial del marcador de ADN plastidial trnH-psbA y reconstruimos las relaciones genealógicas entre los haplotipos. La distribución actual y la predicha mostraron una disyunción entre Córdoba y San Luis, pero la distribución actual presentó una disyunción entre SC y CG que no fue modelada en la distribución potencial. Se obtuvieron 8 haplotipos de distribución restringida con bajos niveles de diferenciación genética agrupados en 4 filogrupos: SC, CG y dos en SL. Nuestros resultados indican que S. linearifolia presentaría baja capacidad de dispersión y que se habría d...

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“…Paleoclimatic reconstructions for the Southern Hemisphere suggest that the last 1-1.4 ka were highly variable encompassing a period of rapid climatic change around the limit between the Medieval Warm Period [MWP] and the Little Ice Age [LIA] (see Mayewski et al, 2004). In central Argentina, several climatic indicators suggest warm and humid conditions for the period 1.4-0.8 ry BP and 0.4-0.3 ry BP (Carignano, 1999;Cioccale, 1999). The first of these two periods was related with a climatic improvement registered by incipient soil development, expansion of the fluvial and lacustrine systems, and formation of swamps in depressions (Carignano, 1999;Cioccale, 1999).…”

Section: Paleoclimatic Significancementioning

confidence: 99%

“…In central Argentina, several climatic indicators suggest warm and humid conditions for the period 1.4-0.8 ry BP and 0.4-0.3 ry BP (Carignano, 1999;Cioccale, 1999). The first of these two periods was related with a climatic improvement registered by incipient soil development, expansion of the fluvial and lacustrine systems, and formation of swamps in depressions (Carignano, 1999;Cioccale, 1999). This phase, that has been correlated with the MWP, was characterized by a temperate, humid to semi-humid climate, with a pluviothermal regime either similar to the recent or perhaps more humid (Carignano, 1999;Cioccale, 1999).…”

Section: Paleoclimatic Significancementioning

confidence: 99%

Historia fósil de las ratas palustres de los géneros <i>Holochilus</i> y <i>Lundomys</i> (Cricetidae, Sigmodontinae) en el Cono Sur de América del Sur

Pardiñas

Teta

2011

Estud. geol.

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The sister genera Holochilus and Lundomys, plus the extinct forms Carletonomys and Noronhomys and the living Pseudoryzomys, constitute a small clade of amphibious sigmodontine rodents that inhabits in tropical and subtropical environments of the Neotropics. Based on almost all the available fossil evidence recovered in Argentina, Bolivia, southeastern Brazil, and Uruguay we revised the paleontological record of Holochilus and Lundomys in southern South America. Past distributions and chronologies indicate the following occurrences [biochrons] for the study area: Holochilus brasiliensis (Middle Pleistocene-Recent in Argentina, Late Pleistocene-Recent in Brazil), H. chacarius (Late Holocene-Recent in Argentina, Early Holocene-Recent in Bolivia), †H. primigenius (Middle Pleistocene in Bolivia), and Lundomys molitor (Middle Pleistocene-Late Pleistocene in Argentina, Late Pleistocene-Recent in Uruguay). Taking into account the present distributions and environmental requirements of these rodents we hypothesize several expansion/retraction episodes of their populations triggered by the occurrence of moist/dry climatic pulses during Pleistocene-Holocene times.

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Climatic fluctuations in the Central Region of Argentina in the last 1000 years

Cited by 89 publications

References 6 publications

North American Droughts of the Last Millennium from a Gridded Network of Tree-Ring Data

North American Droughts of the Last Millennium from a Gridded Network of Tree-Ring Data

Rango geográfico y estructura espacial de linajes genéticos en Sophora linearifolia (Fabaceae), un arbusto endémico de las sierras centrales de Argentina.

Historia fósil de las ratas palustres de los géneros <i>Holochilus</i> y <i>Lundomys</i> (Cricetidae, Sigmodontinae) en el Cono Sur de América del Sur

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