Southern Region Of South America Research Articles

Bacterial bioerosion in human and animal bones from subtropical environments (Northern Pampa/Middle Paraná River Basin, República Argentina)

Microbial bioerosion is a major diagenetic factor determining the long-term survival of archaeological bones as well as the quantity and quality of the biological information retrievable from them. In spite of this, information about bioerosion is still scarce from a worldwide perspective, with most of the data coming from the European continent. In this connection, the primary aim of this paper is to present the first results of an ongoing study oriented at identifying patterns of bacterial bioerosion in human and animal bone samples recovered at different Late Holocene archaeological sites from the subtropical environments of the Middle Paraná River Basin and the Northern Pampa Plain, República Argentina. These results differ in some respects from those obtained in other regions and climates, particularly the temperate belt of Europe, but are consistent with data from a nearer zone, the southern Pampas of East-Central Argentina. The main differences with most of the European samples investigated so far lie in the higher intensity of the bacterial attack on bones, which is reflected in the placement of the first and second frequency distribution modes at lower values of the Oxford Histological Index (0 and 3, respectively), an absence of cases with excellent histological preservation (i.e. OHI = 5) and, finally, a higher frequency and intensity of bioerosion in disarticulated animal bones and in those of humans interred as secondary burials. The causes of the observed differences are still not well understood, being probable that they are linked to higher levels of bacterial activity in the soils of this subtropical region of southern South America.

Historical biogeography of the fern genus Polystichum (Dryopteridaceae) in Austral South America

A group of seven endemic Polystichum species inhabit Patagonia, the southern region of South America. To date, evolutionary relationships of these Austral South American Polystichum remain unknown. The biota of the Southern Andes appears to be more closely related to the temperate Australasian species than to northern South American ones. Differences in morphological characters suggested that Austral South American Polystichum follows that biogeographical pattern, not being closely related to their congeners in the Northern and Central Andes. We sought to reveal the evolutionary relationships, estimate the divergence times and reconstruct both ancestral areas and ancestral ploidy levels of Austral South America Polystichum. Phylogenetic relationships were estimated using maximum likelihood and Bayesian approaches. The seven Austral South American species plus 31 Polystichum species spanning all other major biogeographic regions were sampled for three DNA markers. Divergence times were estimated in BEAST and Bayesian binary Markov chain Monte Carlo reconstruction was applied in order to infer ancestral areas. The evolution of ploidy was reconstructed on the maximum clade credibility tree, using stochastic character mapping. Austral South American Polystichum was recovered as monophyletic. The earliest divergence reconstructed within the Austral South American Clade was that of Polystichum andinum; subsequently two other lineages diverged comprising the remaining Austral South American species. The Austral South American lineage is not closely allied to North and Central Andes congeners. Long-distance dispersal of an ancestral tetraploid from Australasia during the late Miocene is the most likely explanation for the origin of Patagonian Polystichum. Then, Pliocene and Pleistocene orogenic and climatic changes may have shaped its diversification in Patagonia.

Seasonal pattern of agonistic and marking behaviour of adult and young pampas deer (Ozotoceros bezoarticus) males

Pampas deer (Ozotoceros bezoarticus) is an endangered species form the southern region of South America. The aim of this study was to describe and compare the seasonal changes in agonistic and marking behaviours in adult and young male pampas deer. The study was conducted in two groups of animals: six adult (4 to 6 years old) and six young (1.5 years old) males. Agonistic and marking behaviours were weekly recorded during 1 year. Both followed a seasonal pattern, closely related to the androgen concentration annual pattern and to the antler cycle. The frequency of both types of behaviours increased before or at the beginning of the rut. In general, the age of the males did not modify greatly the pattern of the agonistic behaviours. Adult males marked more frequently than young males, especially with the preorbital gland—a behaviour also used as a visual signal for other males in other deer species—also with a clear seasonal pattern. Overall, we concluded that pampas deer males have a seasonal pattern of agonistic and marking behaviours closely associated with the reproductive seasonal pattern.

Late Quaternary aeolian and fluvial-aeolian deposits from southwestern Pampas of Argentina, southern South America

The central region of Argentina, southern South America, is characterized by an extensive Quaternary aeolian record. In this context, three locations from the southwestern Pampas, an Andean foreland region bearing a rich fossil mammal record that contributed to the South America biostratigraphic scheme, were selected to carry out a comprehensive sedimentological analysis of the late Quaternary deposits. The case studies are located at the Transverse Valleys of La Pampa province (Chapalcó, Quehué and Utracán-Argentino valleys), and exhibit a high resolution of the late Quaternary in comparison with others areas of the southwestern Pampas. The Toay locality (~36° 41′S, 64° 24′W) records aeolian-dominant activity since the end of the Late Pleistocene (~30 ka) onwards, soil formation at some point during the Holocene and early–mid 20th century reactivation of aeolian process. The Arroyo Quehué locality (~37°04′S, 64°42′W) presents a Late Pleistocene-Holocene succession mostly related to an ephemeral endorheic fluvial system, with an interval of relative surface stabilization and aeolian aggradation during the Late Holocene. The Utracán locality (~37°17′S, 64°35′W) exhibits a prevailing aeolian and fluvial-aeolian interaction succession developed in the mid-to Late Holocene in a sand-mud flat environment of a shallow saline lake. The three studied cases are representative of aeolian aggradation in association with ephemeral fluvial, shallow lake and pedogenic processes in a currently subhumid-dry region. Numerical ages indicate sedimentation during the last ~30 kyr. They allow constraining and evaluating the paleoenvironmental conditions in this inland region of southern South America, and provide age constraints for the regional databases of paleoclimatic proxies. The results are in agreement with other late Quaternary paleoclimatic-paleoenvironmental archives of central Argentina and show a fragile aeolian landscape that is susceptible to deterioration under extreme conditions, including both aeolian reactivation during dry phases and erosion of sandy-silty sediments during wet phases.

Patterns of tree species variation across southern South America are shaped by environmental factors and historical processes

The southern portion of South America, which encompasses high and exceptional lineage diversity, is well-suited to studies addressing the interaction between biogeography and local environmental conditions and how this historical process and environmental variables affect distribution patterns. We here assessed the role of environmental variables and spatially autocorrelated processes in driving tree species distribution patterns in the whole southern South America forests. We compiled a dataset containing 110,087 occurrence records of 3183 species distributed into 742 sites across six countries and 13 biomes. We modeled the influence of both environmental and spatial variables related to geographic distribution limitations on the variations of species composition through partial canonical redundancy analysis. We built such models for each of our four datasets: the whole extratropical area of South America; Atlantic and Pampa Biomes; dry communities east of the Andes; and communities west of the Andes. Both spatial and environmental variables affect tree species composition in the southern region of South America, although a major role is played by the “pure” spatial fraction. This greatest significance of spatial structures reinforces the importance of historical process for this region and the floristic dissociation existing between the tropical and extratropical portion of South America. We argue that the southern South American forests (especially their temperate portion) should not be lumped into the Neotropical Floristic Province, an idea of utmost importance for the conservation of these high-diversity austral forests.

Phylogenetic study of the genera of Trichopterygini from Austral South American (Lepidoptera: Geometridae): a new classification

Phylogenetic study of the genera of South American Austral Trichopterygini (Lepidoptera: Geometridae, Larentiinae): a new classifi cation. In this work, we evaluate the taxonomy of the Trichopterygini in Chile based on a phylogenetic analysis of the morphological attributes. In our analysis, we used Tatosoma and Sauris as outgroups. Two approaches were used to evaluate phylogenetic relationships: 1) parsimony criterion, and 2) Bayesian inference. Parsimony analysis was conducted in PAUP software, and Bayesian analysis with Markov chain Monte Carlo using the BayesPhylogenies software. Our results based on the phylogenetic hypothesis suggest a new taxonomic order for Trichopterygini of the Andean Region of Southern South America. The valid genera are: Arrayanaria Parra, Butleriana Parra, Danielaparra Kemal & Kocak, Fueguina Parra, Hoplosauris Butler, Lagynopteryx Berg, Llampidken Parra & Santos-Salas, Pachrophylla Blanchard, Parapachrophylla Parra, Rindgenaria Parra, Tomopteryx Philippi, Triptila Warren, Triptiloides Parra & Santos-Salas, Warrenaria Parra. The main changes with respect to the previous taxonomic order are: 1) the genus Lagynopteryx Berg is subordinated under the Trichopterygini; 2) Toxopaltes Warren is a junior synonym of Lagynopteryx; 3) Hoplosauris moesta is transferred to the genus Llampidken; 4) Llampidken valdiviana is a junior synonym of L. moesta; 5) Oparabia arenosa is newly combined with the genus Arrayanaria; 6) Danielaparra viridis is a junior synonym of D. fragmentata; 7) Lobophoraimbricaria is newly combined with the genus Danielaparra; 8) Triptiloides fasciata is a junior synonym of T. randallae; and 9) Parapachrophylla michelleae Parra n. sp. is described. Andean Region species are more closely related to the genus Tatosoma from New Zealand, the synapomorphies that demonstrate this are: swollen metaepimeron and hypertrophy of the second abdominal segment. A checklist of the genera and species of the tribe in the region, and the fi gures of adults and genitalia of some species are included.

A new species of Opisthodactylus Ameghino, 1891 (Aves, Rheidae), from the late Miocene of northwestern Argentina, with implications for the paleobiogeography and phylogeny of rheas

ABSTRACTA new species of rheid, Opisthodactylus kirchneri, sp. nov., is erected on the basis of associated elements of both hind limbs from the late Miocene in northwestern Argentina. The new species extends the biochron of Opisthodactylus from early Miocene to late Miocene and its distribution from Patagonia to northwest Argentina. Cladistic analysis recovered an Opisthodactylus-Pterocnemia clade as sister to a Rhea americana clade. The Opisthodactylus-Pterocnemia clade would have inhabited the most southern, central, and western regions of southern South America throughout the early-middle Neogene, whereas the Rhea stock would have had a north-northeastern or Brazilian ancestral distribution in the lowlands of the continent. The similar biogeographic patterns of living and fossil rheids, cariamids, and tinamids seem to roughly reflect the environmental shift from closed to open habitats that took place at the southern end of South America during the Neogene and Pleistocene, and at least in the former two families the effects of isolation produced by the ‘Paranaense’ sea. Closed-habitat taxa of these three families are recorded at early Miocene localities in Patagonia (O. horacioperezi, O. patagonicus, Noriegavis santacrucensis, and Crypturellus reai), whereas open-habitat taxa come from late Miocene–early Pliocene sites at central (Pterocnemia sp. and Eudromia sp.), northwestern (O. kirchneri and Pterocnemia cf. mesopotamica), and northeastern (Pterocnemia mesopotamica) regions in Argentina.http://zoobank.org/urn:lsid:zoobank.org:pub:0BAD0813-31F8-4101-8742-93BDBCABE807Citation for this article: Noriega, J. I., E. A. Jordan, R. I. Vezzosi, and Juan I. Areta. 2017. A new species of Opisthodactylus Ameghino, 1891 (Aves, Rheidae), from the late Miocene of northwestern Argentina, with implications for the paleobiogeography and phylogeny of rheas. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1278005.

The zooplankton of the shallow lakes of the semi-arid region of southern South America

The southern region of South America is arid and semi-arid, with an east–west gradient of precipitation. Most of its aquatic ecosystems are temporary lakes, with large variations in level and salinity. Although some ecological aspects of these lakes have been studied, the information on the relations between zooplankton and water chemistry, predation, effects of human activities, and the trophic status is scarce and scattered. The objective of this study was to determine the zooplanktonic composition, density, and biomass and their relationships with environmental variables in lakes of different phytogeographic regions of this region (Argentinian central pampa), subjected to different anthropic influences. Samples were taken from ten lakes with a salinity gradient between 0.38 and 115.5 g∙L−1 . The chemical composition revealed a distinction between sodic-bicarbonated and sodic-chlorinated lakes. We recorded 19 crustaceans and 30 rotifers and found inverse relationships between the richness and density and salinity and concentrations of most ions. Bicarbonated lakes were subsaline and characterized by greater richness and density, caused by rotifers. The most frequent species were Brachionus caudatus and Keratella tropica , and the crustaceans Bosmina huaronensis and Microcyclops anceps . The sodic-chlorinated lakes had lower richness and densities, and with distinguishable hyposaline and mesosaline populations with a predominance of neotropical endemic crustaceans, such as Moina eugeniae and Boeckella poopoensis , and hypersaline lakes with a predominance of Artemia permisilis . The biomass did not differ, but lakes with introduced fish fauna (subsaline and hyposaline) had smaller zooplankton, indicating the importance of the top down-effect in the zooplankton community structure.

Antioxidant and antibacterial potential of butia (Butia catarinensis) seed extracts obtained by supercritical fluid extraction

The Butia catarinensis species are native to the southern region of South America. Most part of the harvested butia fruits is used to produce frozen pulp, while the seeds are usually discarded. Considering that, butia seeds are practically unexplored scientifically or commercially, this study aimed to provide an alternative to valorize this industrial waste. Different extraction methods were compared in terms of process global yield, extract composition, total phenolic content (TPC), and also antioxidant and antimicrobial activities of the recovered extracts. The methods used were: supercritical fluid extraction (SFE) conducted at 40°C–60°C and pressures from 100 to 300bar, and the low pressure extractions (LPE) – ultrasonic assisted (UE) and Soxhlet (SE) – with different solvents. The method SE using ethanol (EtOH) as solvent provided the best extraction yield (18.4%). The extracts obtained by ETOH and ethanol-water (EtOH-H2O) (1/1, v/v) presented the best TPC values and antioxidant performance. The extracts obtained by SFE at 40°C/200bar, 50°C/100bar, 60°C/300bar and by LPE with ETOH and EtOH-H2O were considered strong bacterial inhibitors. The main identified compounds were cinnamic acid and caprylic acids.

Thermal response in pre-imaginal biology of Ochlerotatus albifasciatus from two different climatic regions.

The biological processes on mosquito could be variable in response to local climatic characteristics. The thermal effects on time and the rate larval development, immature survival and adult size in local populations of Ochlerotatus albifasciatus (Macquart) (Diptera: Culicidae) from cold (Sarmiento) and temperate (Buenos Aires) regions from Argentina were evaluated. This species affects livestock production and human health. Larvae of both regions were placed in breeding thermal baths (11-32 °C range). Development and survival were recorded daily until adult emergence. The development temperature threshold and thermal constant for Sarmiento (4.59 ± 3.08 °C, 204.08 ± 7.83 degree days) was lower and higher than Buenos Aires, respectively (8.06 ± 1.81 °C, 149.25 ± 2.6 degree days). At cold temperatures (11-16 °C), Sarmiento larvae demonstrated 5 days faster development and higher survival (56%) than Buenos Aires (15%), whereas at warm temperatures (20-32 °C) were up to 2 days slower and similar survival (16% vs. 18%). The size did not show differences between populations. An Ochlerotatus albifasciatus population seems to present local thermal responses. The favourable temperature for survival and rate of development would vary within a cold or warm range, and these differential responses would explain the wide geographical distribution in different climatic regions of southern South America.

CLIMATE CHANGE IMPACTS ON LATIN AMERICAN FARMLAND VALUES: THE ROLE OF FARM TYPE.

This paper examines climate change impacts on South American agricultureusing a set of Ricardian regressions estimated across different samples of farms in SouthAmerica. Regressions are run for the whole sample and for subsamples of crop-only,mixed, and livestock-only farms. The results indicate that climate sensitivity varies agreat deal across each type of farm. The analysis also reveals that the impacts will varysubstantially across South America. The hot and wet Amazon and Equatorial regionsare likely to lose the most from warming scenarios whereas the more temperate highelevation and southern regions of South America will likely gain.

Diet of the lizard Liolaemus occipitalis in the coastal sand dunes of southern Brazil (Squamata-Liolaemidae).

Knowledge of a species' diet provides important information on adaptation and the relationship between the organism and its environment. The genus Liolaemus occurs in the southern region of South America and is an excellent model to investigate the adaptive processes of vertebrate ecology in ecosystems of this region of the world. Liolaemus occipitalis is an endangered species that inhabits the coastal sand dunes of southern Brazil. This species is the most abundant vertebrate in this environment, and it presents unique adaptation characteristics to the restinga environment. The present study analyzed this lizard's diet to verify similarities or differences between this species and other species of the same genus. Specimens were collected monthly from January 1996 to December 1997. The number of items, frequency of occurrence and volume of each prey taxon were determined. Arthropods were identified to the order level, and plant material was identified as flower, fruit, seed and leaves. Variations in the diet of males and females, adults and juveniles and seasons were also analyzed. The data indicate that Liolaemus occipitalis is a generalist, "sit-and-wait" or ambush predator as well as omnivorous, feeding on both arthropods and plant material. Significant ontogenetic differences were verified. Juveniles are more carnivorous, and the intake of plant material increases with size and age. Seasonal differences in diet composition were also observed. In the spring, arthropod and plant materials were more diversified and, therefore, consumed more often.

Axel Elof Jäderholm (1868–1927) of Sweden: educator, hydrozoan zoologist and botanist

Axel Elof Jäderholm was born in Söderhamn, Sweden, on 24 July 1868. In 1888 he entered Uppsala Universitet, earning undergraduate (1892) and doctorate (1898) degrees. His doctoral dissertation was based on an anatomical study of South American Peperomia (Piperaceae). While a graduate student he commenced research on hydroids in collections at the university's natural history museum. A science teacher by profession, he served schools in Uppsala (1900–1901), Norrköping (1901–1905; 1913–1927), Örebro (1905) and Västervik (1905–1913). In addition to teaching, he undertook research in botany (especially mosses) and zoology (hydroids). A focus of work between 1903 and 1905 involved examination of hydroid collections at the Naturhistoriska Riksmuseet (Stockholm) and the Imperial St Petersburg Academy of Sciences (Russia). Jäderholm's field work dealt largely with bryophytes, although his scientific publications (21 of 28) were mostly on taxonomy of hydroids. His hydroid work was mainly on species from northern Europe, the Antarctic and sub-Antarctic, southern regions of South America, and the western Pacific (especially Japan). He established two new genera and 69 new species of hydroids, a majority of the latter still being recognized as valid. Jäderholm was created a knight of the Order of the Polar Star (Riddare av Nordstjärneorden) in Sweden for accomplishments in science and education. After suffering a series of acute illnesses over the last two years of his life, he died in Norrköping on 5 March 1927 and was buried in Uppsala. Five species of hydroids have been named in his honour.

Evaluating, partitioning, and mapping the spatial autocorrelation component in ecological niche modeling: a new approach based on environmentally equidistant records

Most species data display spatial autocorrelation that can affect ecological niche models (ENMs) accuracy‐statistics, affecting its ability to infer geographic distributions. Here we evaluate whether the spatial autocorrelation underlying species data affects accuracy‐statistics and map the uncertainties due to spatial autocorrelation effects on species range predictions under past and future climate models. As an example, ENMs were fitted to Qualea grandiflora (Vochysiaceae), a widely distributed plant from Brazilian Cerrado. We corrected for spatial autocorrelation in ENMs by selecting sampling sites equidistant in geographical (GEO) and environmental (ENV) spaces. Distributions were modelled using 13 ENMs evaluated by two accuracy‐statistics (TSS and AUC), which were compared with uncorrected ENMs. Null models and the similarity statistics I were used to evaluate the effects of spatial autocorrelation. Moreover, we applied a hierarchical ANOVA to partition and map the uncertainties from the time (across last glacial maximum, pre‐insustrial, and 2080 time periods) and methodological components (ENMs and autocorrelation corrections). The GEO and ENV models had the highest accuracy‐statistics values, although only the ENV model had values higher than expected by chance alone for most of the 13 ENMs. Uncertainties from time component were higher in the core region of the Brazilian Cerrado where Q. grandiflora occurs, whereas methodological components presented higher uncertainties in the extreme northern and southern regions of South America (i.e. outside of Brazilian Cerrado). Our findings show that accounting for autocorrelation in environmental space is more efficient than doing so in geographical space. Methodological uncertainties were concentrated in outside the core region of Q. grandiflora's habitat. Conversely, uncertainty due to time component in the Brazilian Cerrado reveals that ENMs were able to capture climate change effects on Q. grandiflora distributions.

Processing Activities and Differentiation of Bird Utilization During the Late Holocene in the Beagle Channel Region (Southern South America)

ABSTRACTRecent research into prehistoric subsistence among the sea nomad societies of the Beagle Channel region of southern South America have shown that there were temporal changes in the utilization of animal resources between the Middle and the Late Holocene. A relative increase in the utilization of fish and birds has been noted in the Late Holocene, together with changes in the selection of bird and fish taxa. The most important change was the appearance of sites in high topographic locations where special activities were recorded that were related to the intensive exploitation of Phalacrocoracidae and the increase in the utilization of Procellariiformes.In this paper, we examine the characteristics of these later assemblages in order to explore possible explanations for the changes in the use of birds. The cut marks on the bones were distinguished in order to differentiate the activities involved. The results indicate that in the Late Holocene there was no differential pattern of cormorant butchering between those sites where special tasks took place and general activity sites. It was also shown that the increase in Procellariiformes was linked mainly to subsistence rather than technological factors. Copyright © 2013 John Wiley & Sons, Ltd.

Development and Practice of the Systems Paradigm in Argentina, Chile and Peru

The systems paradigm has been developing in the southern region of South America for more than three decades, albeit at different paces and with a variety of achievements as can be expected when describing the process of countries as diverse as Argentina, Chile and Peru. This article describes the circumstances and actions that have enabled the systemic approach to gain a legitimate place in the local psychotherapy field permeating family, marital/couple, and individual therapy. Moreover, the family/contextual perspective has attained a valued respectability in the family legal system as well as in community interventions. Overall, the community is aware of and at ease with this efficacious contextual approach. As in other parts of the world, the universities have joined the private entities in the training endeavor and the accreditation process is a complex goal with obstacles that have not yet been surmounted.

A second, cryptic species of the soft coral genus Incrustatus (Anthozoa: Octocorallia: Clavulariidae) from Tierra del Fuego, Argentina, revealed by DNA barcoding

The encrusting soft coral Incrustatus comauensis is a common denizen of hard substrates in the shallow sub-tidal zone from the central Chilean fjords to the Cape Horn region of southern South America. DNA barcoding of specimens collected from the Beagle Channel, Tierra del Fuego, Argentina, revealed the presence of a second, cryptic species of Incrustatus that is syntopic with I. comauensis. We describe Incrustatus niarchosi, a new species that can be distinguished morphologically from I. comauensis by differences in the microscopic ornamentation of the coenenchymal sclerites. To date, I. niarchosi n. sp. is known only from the Beagle Channel. A population of I. comauensis discovered in the intertidal zone in eastern Tierra del Fuego represents a new record of the species for that habitat and geographic region. Although the intertidal population is also distinct genetically, it is morphologically indistinguishable from sub-tidal Chilean populations of I. comauensis, and at present, there is insufficient evidence to support its status as a separate species.

Maintaining Coral Snakes (Micrurus nigrocinctus, Serpentes: Elapidae) for venom production on an alternative fish-based diet

American Elapid snakes (Coral Snakes) comprise the genera Leptomicrurus, Micruroides and Micrurus, which form a vast taxonomic assembly of 330 species distributed from the South of United States to the southern region of South America. In order to obtain venom for animal immunizations aimed at antivenom production, Coral Snakes must be kept in captivity and submitted periodically to venom extraction procedures. Thus, to maintain a snake colony in good health for this purpose, a complete alternative diet utilizing an easily obtained prey animal is desirable. The development of a diet based on fish is compared to the wild diet based on colubrid snakes, and assessed in terms of gain in body weight rate (g/week), longevity (weeks), venom yield (mg/individual), venom median lethal dose (LD50) and venom chromatographic profiles. The animals fed with the fish-based diet gained more weight, lived longer, and produced similar amount of venom whose biological and biochemical characteristics were similar to those of venom collected from specimens fed with the wild diet. This fish-based diet appears to be suitable (and preferable to the wild diet) to supply the nutritional requirements of a Micrurus nigrocinctus snake collection for the production of antivenom.

Fire history in western Patagonia from paired tree-ring fire-scar and charcoal records

Abstract. Fire history reconstructions are typically based on tree ages and tree-ring fire scars or on charcoal in sedimentary records from lakes or bogs, but rarely on both. In this study of fire history in western Patagonia (47–48° S) in southern South America (SSA) we compared three sedimentary charcoal records collected in bogs with tree-ring fire-scar data collected at 13 nearby sample sites. We examined the temporal and spatial correspondence between the two fire proxies and also compared them to published charcoal records from distant sites in SSA, and with published proxy reconstructions of regional climate variability and large-scale climate modes. Two of our three charcoal records record fire activity for the last 4 ka yr and one for the last 11 ka yr. For the last ca. 400 yr, charcoal accumulation peaks tend to coincide with high fire activity in the tree-ring fire scar records, but the charcoal records failed to detect some of the fire activity recorded by tree rings. Potentially, this discrepancy reflects low-severity fires that burn in herbaceous and other fine fuels without depositing charcoal in the sedimentary record. Periods of high fire activity tended to be synchronous across sample areas, across proxy types, and with proxy records of regional climatic variability as well as major climate drivers. Fire activity throughout the Holocene in western Patagonia has responded to regional climate variation affecting a broad region of southern South America that is teleconnected to both tropical- and high-latitude climate drivers-El Niño-Southern Oscillation and the Southern Annular Mode. An early Holocene peak in fire activity pre-dates any known human presence in our study area, and consequently implicates lightning as the ignition source. In contrast, the increased fire activity during the 20th century, which was concomitantly recorded by charcoal from all the sampled bogs and at all fire-scar sample sites, is attributed to human-set fires and is outside the range of variability characteristic of these ecosystems over many centuries and probably millennia.

Evolutionary History of the South American Mistletoe <I>Tripodanthus</I> (Loranthaceae) Using Nuclear and Plastid Markers

Tripodanthus consists of three species that are endemic to South America. While T. acutifolius and T. flagellaris have east-west distributions in tropical and subtropical South America, T. belmirensis is restricted to its type locality in the region of Belmira, Colombia. The objective of the present study was to reconstruct the phylogeny of the genus using molecular markers (nrDNA ITS and plastid atpB-rbcL and trnL-F regions) and to examine morphological characters in the variable species T. acutifolius. A total of 23 individuals of Tripodanthus, representing all species currently recognized in the genus, were sampled in the molecular phylogeny, while 73 individuals were measured for the morphological component of this study. Phylogenetic analyses of the combined ITS and plastid markers reconstructed two main clades within T. acutifolius that correspond to two geographic areas: the Andes and the eastern region of southern South America. This analysis also yielded a monophyletic T. flagellaris, although no geographic structure was obtained within this clade. Tripodanthus belmirensis and T. acutifolius together formed a clade that was sister to T. flagellaris. A principal component analysis of 70 individuals of T. acutifolius showed great variability in leaf morphological characters, leading to overlapping clusters for Andean and eastern mistletoes. The morphologically variable T. acutifolius was not well supported as monophyletic and possessed overlapping morphological features with T. belmirensis, calling into question whether T. belmirensis should be recognized as a distinct species. Keywords—Amphiphagy, Andes, Brazil, biogeography, host plant, parasitic plant, Santalales.