Police Coordination in the Southern Cone

Historical biogeographic patterns of relationships among southern and northern South America, North America, and southern temperate areas were investigated by a cladistic biogeographic analysis of 17 taxon cladograms. Three techniques were applied: Wiley's biogeographic parsimony analysis, Nelson and Platnick's component analysis, and Humphries, Ladiges, Roos, and Zandee's quantification of component analysis. Biogeographic parsimony analysis yielded two general area cladograms (CI = 0.74). Under component analysis, six general area cladograms (two under Nelson and Platnick's assumption 1 and four under their assumption 2) were obtained through the intersection of a maximum of 10 sets of area cladograms. Quantification of component analysis produced nine cladograms (CI = 0.50) under assumption 1 and one (CI = 0.45) under assumption 2. The results support a hybrid origin of the South American biota. The northern South American biota is most closely related to that of North America, and southern South America constitutes a monophyletic group together with Australia, Tasmania, New Guinea, New Caledonia, and New Zealand, reflecting the existence of an ancient austral biota. Four conflicting hypotheses of area relationships concerning southern South America and the other austral areas are proposed, suggesting that southern South America may be a composite area in itself. [South America; cladistics; biogeography; parsimony analysis; component analysis.]

Unusual past dry and wet rainy seasons over Southern Africa and South America from a climate perspective

Mineralogical, Chemical, and Isotopic (Sr, Pb) Composition of Atmospheric Mineral Dusts in an Ombrotrophic Peat Bog, Southern South America

Variations in surface temperature of the Pacific sector of the Southern Ocean result in similar changes downwind in South America. Northward in South America the influence of the Southern Ocean decreases and that of the Atlantic Ocean increases. Northward retreat of tropical vegetation in southern South America during the Late Eocene and Early Oligocene reflects contemporaneous cooling of the Southern Ocean. The glacial history of southern South America after the onset of major glaciation 3.5 MY ago likewise must reflect Early Pliocene cooling of the Southern Ocean. Oxygen isotopic studies of deep-sea cores suggest that conditions in coastal Antarctica first became frigid at the beginning of the Oligocene ca 37 MY ago, when the sea froze and glaciers extended to sea level. However, other deep-sea core studies suggest that conditions did not become severe until the end of the Oligocene ca 26 MY ago, when ice rafting began and tree species were exterminated. The later date is considered the more reliable because it is based on more direct evidence. According to oxygen isotopic studies, the East Antarctic ice sheet accumulated from 14 to 10 MY ago. If so, the West Antarctic ice sheet, whose situation largely below sea level precludes it ever having been composed of temperate ice, must have formed after 10 MY ago. Its emplacement would have caused a rather abrupt northward expansion of cold Antarctic water; such an event has been noted in Early Pliocene time soon after 5 MY ago. Evidence for an earlier comparably cold episode in Late Miocene time ca 6 MY ago is equivocal. This suggests that the West Antarctic ice sheet first formed during the Early Pliocene. If so, its formation may have been triggered by the ocean freshening caused by massive evaporite deposition in the Mediterranean basis 5.5–5 MY ago. Some geological evidence, however, and some recent reassessments of oceanographic evidence, suggest that the West Antarctic ice sheet was present by about 7 MY ago. Initiation of glaciation in southern South America 743.5 MY ago does not disprove a 7 MY ago for the West Antarctic ice sheet, but it favours a younger age. During the Gauss Epoch 3.3–2.4 MY ago oceanographic studies suggest an unlikely interhemispheric contrast: a return to comparative warmth in high southern latitudes, and the start of major mid-latitude glaciation in the Northern Hemisphere. Unfortunately, little is known about glacial events in South America during this interval. After ∼ 2.1 MY ago repeated glaciations in southern South America undoubtedly correspond to repeated severe coolings of the Southern Ocean, but the individual episodes cannot yet be correlated. During the last interglacial the oxygen isotopic content of ocean water implies less global ice cover than today's. In southern Chile, deep chemical weathering at that time suggests exceptional warmth. These observations support the hypothesis that the ca + 6 m sea level ca 125 000 years ago resulted from deglaciation of West Antarctica when temperatures rose above the critical level for ice shelves. During the last glaciation world ice volume was greatest ca 18 000 BP, implying that the Northern Hemisphere mid-latitude ice sheets were then largest. In south-central Chile, however, glaciers were largest – and by inference, temperatures were lowest – before 56 000 BP. After a smaller readvance culminating ca 19 500 BP the Chilean glaciers shrank during a major interstade and later readvanced, probably until about 13 000 BP. This oscillation is not evident in the sub-Antarctic Indian Ocean cores, but may be shown by the poorly-dated Byrd Station (Antarctica) core. After 13 000 BP, southern South America warmed rapidly, and by 11 000 BP glaciers were within their present borders, where they remained during the Younger Dryas Stade, ca 11 000–10 000 BP, the final European interval of severe cold. This early recession (compared to the North Atlantic area) is compatible with maximum postglacial warmth ca 9 400 ± 600 BP in the sub-Antarctic Indian Ocean, and strongly suggests that the North Atlantic was a highly atypical part of the world ocean during deglaciation of North America and Eurasia. Former large lakes in South Victoria Land, Antarctica, dammed by grounded Ross Sea ice, imply temperatures at least as high as today's. A Late Wisconsin age has been suggested, but this seems unlikely, because southern South America was then much colder. The lakes may have formed early in the Southern Hemisphere hypsithermal, starting ca 11 000 BP, when eustatic sea level, which probably controlled the extent of the grounded Ross Sea ice, was still low. In Peru at lat 14° S, at a site dominated by air from the equatorial North Atlantic during the accumulation season, initial results suggested that a minor readvance occurred during Younger Dryas time, but further studies consistently indicate that the advance culminated at least 500 years earlier, ca 11 000 BP. By 10 000 BP the Peruvian glaciers were little, if any, larger than they are today. During Neoglacial time glaciers in southern South America were largest about 4 500 BP, whereas in the Northern Hemisphere a contemporaneous advance was relatively smaller. This suggests that the inferred cooling was caused by an event in high southern latitudes, perhaps greatly increased calving from West Antarctica. A later Neoglacial advance in southern South America culminated ca 2 700–2 200 BP, as in many other parts of the temperate zones of both hemispheres. Throughout this interval in Peru, however, ice was less extensive than it is today.

This study describes the climatological characteristics of regional heat waves (HWs) over southern South America (SSA) for the warm seasons (October–March) of 1979–2018 based on daily maximum temperature series from 131 weather stations. Clustering of stations with high co-occurrence of simultaneous HW days is employed to identify regional HW events over five homogeneous regions: northern, central-eastern and southern SSA regions, central Argentina, and central Chile. When all regions are considered, we find a mean frequency of ∼4 HWs per year. Transitional regions (northern SSA, central-eastern SSA and central Argentina) are characterised by longer, albeit less intense, HWs than the southernmost region (southern SSA), whereas central Chile events display the lowest duration, intensity and extension. By aggregating these single HW attributes into a combined severity index, a ranking of historical HWs has been obtained, with the March 1980 event standing as the most severe one of SSA. The assessment of long-term changes reveals significant increases in the frequency of regional HW days over central Argentina and central Chile only. Trends in HW characteristics are also region dependent, and the southernmost region is the only one where HW severity has increased significantly.We report similarities and differences in the synoptic circulation patterns associated with regional HW events. Southern SSA HWs have the most distinctive signatures, related to extratropical high-pressure systems blocking the westerly flow. In the remaining regions, HWs are associated with anomalies in the South Atlantic (northern SSA, central-eastern SSA and central Argentina) or South Pacific (central Chile) High, and the intensification of the northerly low-level flow by regional thermal lows and South American Low Level Jet events. Regional HWs often migrate from northern to central-eastern SSA and central Argentina, following the displacement/intensification of the South Atlantic High, which partially explains the similarity of their associated patterns.

Commerson’s dolphins (Cephalorhynchus commersonii) are separated into the subspecies C. c. commersonii, found along southern South America (SA) and the Falkland Islands/Islas Malvinas (FI/IM), and C. c. kerguelenensis, restricted to the subantarctic Kerguelen Islands (KI). Following the dispersal model proposed for the genus, the latter is thought to have originated from SA after a long-distance dispersal event. To evaluate this biogeographic scenario, a distribution-wide, balanced sampling of mitochondrial DNA (mtDNA) control region sequences was designed. New tissue samples from southern Chile, Argentina, FI/IM, and KI were added to published sequences from SA and KI, for a total of 256 samples. Genetic diversity indices, genetic and phylogeographic structure, and migration rates were calculated. One haplotype was shared between subspecies, with which all haplotypes of C. c. kerguelenensis formed a distinct group in the haplotype network. A new haplotype for C. c. kerguelenensis is reported. Differentiation in haplotype frequencies was found among localities within the distribution of C. c. commersonii, yet the phylogeographic signal was only statistically significant between subspecies. Coalescent-based historical gene flow estimations indicated migration between the northern and southern portions of the species’ range in SA as well as between SA and the FI/IM, but not between these and the KI. The net nucleotide divergence between dolphins from SA and the FI/IM was lower than the recommended threshold value suggested for delimiting subspecies, unlike that found between C. c. commersonii and C. c. kerguelenensis. The results are consistent with the model of post-glacial colonization of KI by South American C. commersonii, followed by an ongoing divergence process and subspecies status. Thus, C. c. kerguelenensis may represent the most recent diversification step of Cephalorhynchus, where isolation from their source population is driving a process of incipient speciation.

In this report, we present a new 14C of 9627–9490 cal BC (8640 ± 30 BP) obtained at the Intihuasi Cave, San Luis, Argentina. The sample was obtained during fieldwork conducted as part of a new management plan for tourist use of the site. Intihuasi has played a central role in the history of archaeological investigations in South America. There, in 1951 González applied for the first time a systematic methodology for archaeological excavations in Argentina. Moreover, he complemented his field results with the obtainment of the first radiocarbon dates for the Southern Cone of South America. These achievements allowed him to build the first macroregional chronological sequence, which is still partially used. The new radiocarbon date presented in this article aims to reconsider the importance of the Intihuasi Cave for the discussion of the macroregional peopling of the Southern Cone of South America. We believe that the site ratifies the occurrence of an Andean population vector in the region.

Episodes of heat stress constrain crop production and will be aggravated in the near future according to short and medium-term climate scenarios. Global increase in cloudiness has also been observed, decreasing the incident solar radiation. This work was aimed to quantify the probability of occurrence of heat stress and cloudiness, alone or combined, during the typical post-flowering period of wheat and canola in the Southern Cone of South America. Extended climate series (last 3–5 decades with daily register) of 33 conventional weather stations from Argentina, Brazil, Chile and Uruguay (23 to 40°S) were analysed considering the period from September to December. Two different daily events of heat stress were determined: (i) maximum daily temperature above 30 °C (T > 30 °C) and (ii) 5 °C above the historical average maximum temperature of that day (T + 5 °C). A cloudiness event was defined in our work as incident solar radiation 50% lower than the historical average radiation of that day (R50%). The T > 30 °C event increased its probability of occurrence throughout the post-flowering phase, from September to December. By contrast, the risk of T + 5 °C event decreased slightly, just like for R50%, and the higher the latitude, the lower the probability of R50%. The T > 30 °C plus R50% combined stresses reached greater cumulated probabilities during post-flowering, compared to T + 5 °C plus R50%, being 42% vs 15% in northernmost locations, 26% vs. 19% in central (between 31 and 35°S) and 28% vs. 1% in southernmost locations, respectively. A curvilinear relationship emerged between the monthly probability of combined stresses and the number of days with stress per month. In summary, T > 30 °C was the most frequent thermal stress during post-flowering in wheat and canola. Both combined stresses had a noticeable risk of occurrence, but T > 30 °C plus R50% was the highest. Evidence of the recent past and current occurrence of heat stress individually, and its combination with cloudiness events during post-flowering of temperate crops, serves as a baseline for future climate scenarios in main cropped areas in the Southern Cone of South America.

A bibliographic analysis was carried out to update the state of knowledge about aquatic fungi belonging to the subkingdom Dikarya in the Southern Cone of South America. The exhaustive search resulted in 38 articles reported. These papers correspond to those on taxonomic, ecological and biogeographic topics and include studies from lotic environments of the temperate ecoregions of Chile and Argentina. A total of 325 aquatic fungal taxa were reported, of which 318 belong to the phylum Ascomycota and 7 to the phylum Basidiomycota. According to the subgroups of these aquatic fungi 17 taxa were aero-aquatic, 199 facultative and 109 Ingoldian fungi. Regarding the methodologies, in these studies the information was obtained mainly by using lignocellulosic substrates such as leaf litter and wood as fungal source and wet chamber traditional working technique. However, more studies are still needed using other few-reported perspectives for the region such as ecological and molecular approaches as well as analyses of water environments belonging to unexplored biomes. This information can contribute to a better understanding of aquatic fungal communities and their role in ecosystems of the Southern Cone of South America.

The common wall gecko (Tarentola mauritanica) has invaded three regions globally: the Azores and Madeira archipelagos, the subtropical and temperate regions of North America, and the south of South America. The information about the invasion in South America is limited, and records suggest rapid expansion in the continent’s south. In this work, we modeled the gecko’s distribution in its native range to identify potential invasion sites in the Southern Cone of South America, updating its geographic distribution and assessing their potential threat to native South American geckos. The most contributive variables in the Species Distribution Model included precipitation of the driest quarter, minimum temperature of the coldest month, and temperature seasonality. The habitat suitable for the expansion of geckos in the Southern Cone covers 1,397,558.36 km2, with the highest being in the north-central part of Argentina. The species Homonota taragui, Homonota williamsii, and Homonota whitii had the greatest degree of overlap with the suitable habitat of T. mauritanica, requiring particular caution against future introductions. This underscores the importance of understanding and mitigating the risks associated with the invasive potential of T. mauritanica in the Southern Cone of South America, specially to the endemic and endangered species, living in rocky areas.

Characterization of a type O foot-and-mouth disease virus re-emerging in the year 2011 in free areas of the Southern Cone of South America and cross-protection studies with the vaccine strain in use in the region

Although glaciated basins are usually associated with nonproductive, poorly sorted strata, hydrocarbons occur in several late Paleozoic glaciated basins of central and southern South America. In Bolivia, the Chaco-Tarija basin has commercial production from more than 30 fields in glacially influenced submarine channel systems (Palmar, Santa Cruz, and Bermejo fields) that accounts for about 60% of current national reserves. Correlative deposits in Argentina host the Campo Duran and Madrejones oil fields. In Brazil, the Parana basin has significant but as yet subcommercial gas shows in thick marine turbidite sandstones of the glacially influenced Itarare Group. The Chaco-Parana basin of Argentina is one of the largest onshore targets for exploration in South America, but it is virtually untested. Glacially influenced foreland basins of Argentina (Tepuel and Paganzo-Maliman) contain complex glacigenic stratigraphies of interbedded tillites and poorly prospective sandstones. In contrast, the glacially influenced marine infills of intracratonic basins in Brazil (Parana), Bolivia, and Argentina (Chaco-Tarija and Chaco-Parana) contain thick sequences of pebbly mudstones and regionally extensive reservoir quality sandstones. The key to the occurrence of good reservoirs and associated trapping mechanisms in these intracratonic basins is the interplay of sediment supply, regional tectonics, and relative sea level changes. Glacial scouring of extensive cratons by ice sheets resulted in the delivery of huge volumes of glaciofluvial sand to deltas. Structural control of drainage patterns on the craton by basement lineaments resulted in persistent sediment sources and depocenters. Frequent earthquake activity along reactivated basement lineaments resulted in downslope mass flow of deltaic sediments and the deposition of thick, amalgamated sand turbidites (reservoirs). Pebbly mudstone seals most likely record higher relative sea levels, resulting from basin subsidence, and deposition from suspended sediment plumes and icebergs. Source rocks are provided by Devonian and Permian shales. This model may be applicable to other parts of Gondwana that contain thick, prospective sandstones in glacially influenced intracratonic basins.

In this chapter climatic changes over southern South America during the last millennium with focus on the period of the Little Ice Age (LIA 1550–1800 AD) are investigated. Results presented are based on proxy and modelling evidence. Proxy studies include a variety of different sites, ranging from geomorphological, lacustrine, pollen to tree ring reconstructions. These different sources of evidence are combined into a multi-proxy network. Based on this network, spatio-temporal climatic changes in southern South America are assessed for the last millennium. A climate model simulation of the last millennium is used to investigate the influence of external forcing parameters, such as solar, volcanic and greenhouse gases on the local climate in southern South America. To compare proxy-based results and the output of the global climate model on a common basis, conceptual and quantitative downscaling and upscaling models are established. Based on these methodological approaches both reconstruction methods indicate a period of wetter conditions in south-eastern South America during the period of the LIA. Investigating the driving mechanisms for hydrological changes during the LIA, large-scale atmospheric circulation changes of the Southern Hemispheric Westerlies (SHWs) over southern South America are indicated in modelling results. Changes of the SHWs during the LIA also fit into the spatial pattern indicated by different proxies with wetter conditions and cooler temperatures in south-eastern South America accompanied with drier and warmer conditions to the north.

The new species Calvitimela austrochilenis Fryday and Tephromela superba Fryday are described: the former from several collections from southern Chile and one from Marion Island, and the latter from southern South America (including the Falkland Islands), Campbell Island, (New Zealand), and Antarctica. Four new combinations are also made in Tephromela: T. atrocaesia (Nyl. ex Cromb.) Fryday from Îles Kerguelen, Heard Island, South Georgia, and southern South America; T. atroviolacea (Flot.) Fryday from southern South America and Îles Kerguelen; T. lirellina (Darb.) Fryday from only southern South America; and T. skottsbergii (Darb.) Fryday, which is shown to be an earlier name for T. austrolitoralis (Zahlbr.) Kalb & Elix, from throughout the region. Lectotypes are selected for Lecanora atrocaesia and L. atroviolacea. The systematic placement of Tephromela eatonii (Cromb.) Hertel from Kerguelen, Marion Island and Bouvetøya is also discussed but the species is retained in Tephromela.

Southern South America is an important dust source to Antarctica. However, there is a lack of overall understanding of the dust event variation in recent decades in South America. Here, we analyzed variations in the dust frequency in southern South America (south of 20°S) from 1986 to 2020 and its causes with large-scale climatic factors, based on observational station data and reanalysis data. During the austral spring and summer, several stations recorded an average dust frequency exceeding 15 days, with some even surpassing 20 days. The frequency of dust events in spring exhibited a strong association with large-scale climate factors. Negative phases of the interdecadal Pacific oscillation (IPO) and the Antarctic Oscillation (AAO) were more likely to lead to an increase in the dust frequency in southern South America. The negative IPO had a greater impact on the Patagonia dust (south of 40°S), resulted from a decrease in the drought index under the influence of downward motion. However, the negative AAO had a greater impact on the dust in South America over 20°–40°S by increasing strong wind frequency and decreasing the drought index over there. On longer time scales, model outputs from the Coupled Model Intercomparison Project phase 6 (CMIP6) also confirmed the combined influence of the negative IPO and negative AAO phases on southern South American dust. Significance Statement It has been shown that dust from South America can be transported to Antarctica through atmospheric circulation. Changes in dust activity in South America have an important impact on the Antarctic climate. Therefore, this study analyzed the changes in dust activity in southern South America from 1986 to 2020. Since large-scale climate factors such as the interdecadal Pacific oscillation (IPO) and the Antarctic Oscillation (AAO) can play an important role in the regional climate, we analyzed the effects of the IPO and the AAO on the South American dust activity and discussed the possible influence mechanisms. This paper will provide some references for understanding dust activity variation in South America and studying dust transport from South America to Antarctica.