Torres Del Paine National Park Research Articles

Validity of Myobradypterygius hauthali von Huene, 1927 (Ichthyosauria: Ophthalmosauria) from the Early Cretaceous of Chile and Argentina

Abstract Early Cretaceous ichthyosaurs were globally distributed pelagic marine reptiles, but many remains are fragmentary, creating a Northern Hemisphere diversity bias. A rich Hauterivian locality near the Tyndall Glacier inside Torres del Paine National Park in southern Chile yields important new data regarding ichthyosaurian diversity along the Pacific margin of Gondwana. These new data will contribute to clarifying questions regarding ichthyosaur taxonomy and the palaeobiogeographical relationships between the southern Gondwanan and Northern Hemisphere ichthyosaur groups during the Early Cretaceous. Here, we describe three new ichthyosaur specimens from this locality. Two of them are referred to Myobradypterygius hauthali, expanding the distribution of this species from the Barremian of Argentina to the Hauterivian of the Chilean Patagonia. This material shows that M. hauthali differs from Platypterygius platydactylus in forefin construction and scapular morphology, supporting its classification as a separate genus within Platypterygiinae. The third specimen is a large-bodied indeterminate ophthalmosaurine ichthyosaur. This record represents the southernmost record of Ophthalmosaurinae and the first occurrence of this group from the Cretaceous of the Southern Hemisphere. These discoveries show that ophthalmosaurines and platypterygiines continued to occur sympatrically in southernmost Gondwana during the Early Cretaceous, expanding the pattern documented in Europe to the Pacific region.

Soil‐vegetation interplay in a Holocene toposequence at Torres del Paine National Park, southern Andes, Chile

AbstractChile's Torres del Paine National Park (TPNP) is one of the most impressive landscapes in southern Patagonia, with unique natural elements on the edge of the southern ice field, where knowledge of soils and ecological relationships is nonexistent. Therefore, the objective of this study was to determine the chemical, physical, mineralogical, and micromorphological characteristics of Holocene soils along a local toposequence representing the main vegetation types of the TPNP. The morphological, chemical, physical, and mineralogical properties of 12 soil profiles were studied and classified according to Soil Taxonomy. Coevolution of vegetation and soil taxa is clearly evident since glaciation, with podsolization under austral Nothofagus pumilio forests leading to the development of spodosols, while paludization in local depressions with Nothofagus forests allowed the formation of histosols. Slopes covered with loess and tephra led to the formation of Andisols with shrub vegetation. Predominant parent materials include till from Late Quaternary advances of southern Andean ice, Pleistocene loess, and volcanic ash from surrounding Chilean volcanoes. The parent materials were strongly influenced by Late Quaternary climatic and landscape changes following the retreat of the Last Glacial Maximum in southern Patagonia, resulting in erosional and depositional conditions (windblown loess, fluvial glacial deposits, and moraines). Stable landforms show the influence of allochthonous volcanic ash shaping Andean features, combined with the accumulation of organic matter in hydromorphic soils. Three main groups of soils have been identified: loess‐rich soils, organic‐rich soils, and poorly developed soils. The latter show low fertility related to recent landforms on different substrates ranging from till, rocky slopes, talus, or glacial deposits. In high mountain regions under periglacial conditions, cryoturbation features indicate seasonal frost–thaw cycles without current permafrost. The diversity of soil orders in the mountains of southern Patagonia is comparable to similar environmental conditions and latitudes in the Northern Hemisphere. However, the andic properties due to volcanic ejecta inputs, as well as organic‐rich soils at low altitudes of bottom valleys, are typical features of the soils at TNTP.

Multisequal aeolian deposition during the Holocene in southwestern Patagonia (51°S) was modulated by southern westerly wind intensity and vegetation type

We studied a multisequal soil succession (MSS) just south of Torres del Paine National Park (51°S), at the present-day core of the Southern Westerly Winds (SWW). The Río Serrano Section comprises paleosol horizons with associated intervening loess and sandy loess beds formed during the Holocene. Our record suggests strong and stable aeolian activity between ∼9.3–7.2 ka followed by a decline with centennial-scale variations until ∼5 ka. A strengthening commenced at ∼5 ka and culminated in a maximum between ∼2.2–0.5 ka with millennial-scale variations. Subsequent weakening of aeolian activity between ∼0.5 and 0 ka was coeval with the deposition of a ∼40 cm-thick paleosol, after which aeolian activity increased abruptly and reached an unprecedented maximum starting in the mid-20th century. The inferred wind intensity variations from our data bear partial agreement with competing hypotheses of SWW evolution, which postulate minimum SWW influence in SW Patagonia during the early Holocene and maximum influence during the Late Holocene, or vice versa. When analyzed through the lens of vegetation physiognomy/distribution and associated hydrological balance inferences from neighboring sites, our results suggest a primary control by precipitation and wind speeds associated to SWW strength at regional scale, modulated by the position of the forest/steppe ecotone east of the austral Andes. Human activities during the mid-20th century (deforestation, fire-regime shifts, livestock grazing, land use changes) caused an unprecedented increase in aeolian activity through decreased vegetation cover that increased sediment availability for aeolian transport, marking a striking difference with the magnitude of natural processes before the Anthropocene. Our results highlight the importance of climate change and natural/human-driven changes in vegetation cover for deciphering wind intensity histories, particularly in the transition from humid to semiarid environments along the eastern slope of the southern Patagonian Andes.

Impact of protection methods and abiotic factors on Nothofagus pumilio seedlings mortality in Torres del Paine National Park, Chile

Impact of protection methods and abiotic factors on Nothofagus pumilio seedlings mortality in Torres del Paine National Park, Chile

Las Torres Reserve’s Sustainable Tourism Practices in Patagonia

Summary This case study is focused on the Chilean adventure travel company, Las Torres Reserve, which has incorporated sustainable tourism practices into its hospitality business in Torres del Paine National Park, Patagonia. The information in this study was gathered through onsite interviews and online research with Las Torres Reserve marketing and management staff during a visit to Las Torres Reserve and the W Circuit in Torres del Paine National Park. The case study used interview and online research to describe the background, history and vision, and sustainable management practices the company has pursued to support conservation of the land and provide education to visitors from all over the world. A thorough presentation of the business and its staff’s practices is outlined, including its variety of accommodation options, sustainability practices, and the work its non-governmental organization (NGO) is doing to support conservation. Hospitality businesses that are in the adventure tourism industry can use this case study as an example of how business management and sustainability initiatives can be used to sustain both a successful tourism business and the land that is essential to its long-term success. Information © The Author 2023

Soil Vulnerability Indicators to Degradation by Wildfires in Torres del Paine National Park (Patagonia, Chile)

Wildfires are a common phenomenon globally, nonetheless some ecosystems are more adapted than others. In this work, we show results of a study conducted in Torres del Paine National Park (Chile) that suffered a big forest fire in 2011, affecting 17,666 ha. The Park is located in the transitional forest-steppe zone whose annual rainfall varies between 300 and 1,500 mm. Plant communities goes from Patagonian steppe, pre-Andean scrub to Magellanic forest. Based on vegetation community and trying to cover all representative sectors affected by the fire, 5 areas of the park were sampled in 2019 following the transects where a vegetation recovery study has been monitored since the fire occurred. Soil parameters used to evaluate were: texture, soil water repellency (WR), organic matter (OM), and aggregation, including total content of macroaggregates (TCA) and their stability (AS). The results showed high values of OM, however three of the 5 areas showed statistically lower values of OM in burned samples. WR was present (from slight to severe) in the 75% of the samples, and without differences between burned and unburned. The correlations analyses indicated that WR is more related with the OM type than with quantity, since better correlations were obtained when only samples from the same area were included in the analyses. The results of aggregation indicated that soils have a poor structural development. The TCA varies from 16 to 50%, and the AS is not very high (average of 66%), being the highest in the area with lowest TCA and more affected by the fire and erosion processes. This suggests that the higher values of AS are a consequence of the destruction and loss of the less resistant fraction after the fire. The combination of the high sand content (low specific surface area) and high OM make them very susceptible to develop WR. Since these soils have a scarce development with a poor structure, the combination of the WR and the poor soil structure make them very vulnerable to erosion processes after the fire. Measures to protect the soils or accelerate the recovery are recommended in these areas when new human caused wildfires could occur.

Predator tourism improves tolerance for pumas, but may increase future conflict among ranchers in Chile

Predator tourism is one strategy to improve tolerance for predators, and support biodiversity and ecosystem health. Torres del Paine National Park (TdP) – a UNESCO Biosphere Reserve in southern Chile - supports productive livestock industries and nascent puma tourism. We compared interviews conducted in the region prior to puma tourism, with results from interviews collected across 45 ranches post-puma tourism. We assessed rancher attitudes regarding pumas, puma-livestock conflict, puma tourism, and linked them with socio-ecological factors. Respondents who viewed pumas as a threat experienced higher livestock losses. Respondents who reported higher sheep losses were inclined to support the lethal removal of livestock-killing pumas, and to initiate a puma hunt, whereas respondents who supported puma tourism disagreed with hunting pumas. Using the Potential for Conflict Index, we found that participants exhibited the highest consensus on the benefit of puma tourism and the lowest consensus over lethal removal of pumas. Our results suggest predator tourism has increased tolerance for pumas but is creating new potential for conflict. Previous to puma tourism, ranchers were almost entirely negative about pumas and unanimously supported illegal puma hunting. Now, most believe that pumas are part of Patagonia's heritage. This divide was best explained by distance to TdP: ranches closer to TdP experienced greater losses to pumas but had neighbours that benefitted most from puma tourism. Therefore, we suggest that tourism revenues supplement community compensation insurance programs that reimburse rancher losses to pumas to mitigate the growing divide between those benefiting from pumas and those experiencing economic hardship.

14C and 10Be dated Late Holocene fluctuations of Patagonian glaciers in Torres del Paine (Chile, 51°S) and connections to Antarctic climate change

Southern Hemisphere Holocene glacier chronologies are important for unraveling past climate change, mid-to-high latitude teleconnections, and regional to global climate forcing. At present, a significant number of glacier chronologies for Patagonia are based on 14C dating, which may afford only maximum- or minimum-limiting dates. Here, we combine geomorphology and stratigraphy with radiocarbon (14C) and beryllium-10 (10Be) surface exposure-age dating at three outlet glaciers, Zapata, Tyndall, and Pingo. These glaciers drain the southernmost tip of the Southern Patagonian Ice Field at Torres del Paine National Park, Chile (51°S). After an expansion that we date at 3200 yr. B.P., the Torres del Paine glaciers expanded to their last major Late Holocene maxima at 600 and 340 yr. B.P., with the final dated readvance after 190 yr. B.P. We use these data, together with other Patagonian glacier records, to define the early, mid and final glacial stages of the last millennium. These cold events were separated by warm conditions that allowed the Nothofagus forest to colonize deglaciated land. The presence of near-concurrent glacier fluctuations in Patagonia and Antarctic Peninsula indicates widespread cooling punctuated the Late Holocene, including the last millennium, across much of the extratropical Southern Hemisphere. We link this cooling to cold oceanographic-atmospheric conditions forced by a northern shift or intensification of the Southern Westerly Winds. Such scenario increased northward advection of cold Antarctic circumpolar water along western Patagonia and favored decreased upwelling of warm circumpolar deep water together with expanded sea ice around the Antarctic Peninsula.

Bacterial and Geochemical Composition of Thrombolites from Lake Sarmiento, Torres del Paine National Park of Chilean Patagonia

Microbialites are organo-sedimentary structures formed as minerals precipitate due to the metabolic activity of microorganisms. They can be differentiated by their internal mesostructure into stromatolites and thrombolites. Lake Sarmiento, located in the Patagonia region of southern Chile, is a sub-saline alkaline lake in which living submerged and sub-fossil thrombolites are present. A submerged thrombolite was collected and one of the fragments was deposited in an experimental aquarium for 1.5 years, in order to examine possible changes to its biological and chemical composition. The bacterial biodiversity was examined using Illumina sequencing of PCR-amplified 16S V4 rRNA genes from total extracted DNA. The chemical structure was studied using XRD and bench chemical methods. The results show that in the living submerged and aquarium thrombolite samples, the Proteobacteria, Verrucomicrobia, Planctomycetes and Bacteroidetes phyla dominated the bacterial communities, which were similar at the upper taxonomic level. However, differences between the samples were detected at deeper classification levels (class, genus). Interestingly, no changes in the carbonate composition of the thrombolites were observed after culturing during 1.5 years. This study is the first to provide new insights into the bacterial community composition of thrombolites from this site. The thrombolites from Lake Sarmiento are active and contain a unique bacterial community composition. Further studies, including greater sampling and greater variety of experimental conditions in vitro (aquarium) will be helpful to create a global understanding of the microbial composition and formation of the thrombolites from Lake Sarmiento.

Mapping of reforestation progress in Chilean National Park Torres del Paine

Abstract. The Torres del Paine National Park is one of the most important of the world due to its particular biotic characteristics, climate and geomorphologic conditions (Mattar et. al, 2012), which makes unique with invaluable attractions for tourists and scientists. Furthermore it is one of the main sources of income generated by tourism in Chile. It is located in the southernmost Chilean region namely Magallanes and Chilean Antarctica and comprises a total of 242242 hectares.Since 1980 several forest fires inside the national park have caused great losses to flora and fauna. Despite several initiatives carried out by the national forest cooperation (CONAF) to reduce the number of forest fires, it was not possible to install sustainable management plans. As a consequence, it is still of huge concern that most of the forest fires are caused by tourists and visitors to the national park. Such as those in 2005 and 2011, that caused damage to a total surface of about 33000 hectares. As a consequence CONAF started to implement an updated reforestation strategy in 2012. The plan prepared by the committee was designed for a period of five years (2012–2016) proposing passive and active restoration measures based on the different ecosystems involved in the national park as it is necessary to reconstruct the original ecosystems and to conserve the biodiversity of the park. For this purpose, it was considered a study carried out by Pisano (1974) and the cartography that defined the park before a 1985 forest fire.The aim of the present study is to quantify and to analyse reforestation campaigns carried out since 2012 in the Torres del Paine National Park. Therefore, we processed Landsat 7 and Landsat 8 satellite imagery acquired between 2011 and 2017. Our methodology is based on the calculation and comparison of the Normalized Burn Ratio.Our approach indicates that almost 19000 hectares were affected by forest fires that took place in 2005 and 2012. Of the total area affected, 17761 hectares presented some degree of severity, of which 28% presented a high degree of severity. Up to 2017, a total of 13067 hectares have been recovered, representing a 70% of the total area affected by the forest fires.After 2012, annual soil recovery can be estimated by 11%, or 1100 hectares. Nevertheless, this does not mean that leafy and tall trees can be found in areas affected by forest fires. It just indicates that soil recuperation has taken part and that vegetation seems to grow. As CONAF principally planted Lenga (Nothofagus pumilio) a slow growing tree species, almost 15 years have to pass before notable effects can be perceived.

Assessment of mountain trails and management measures to mitigate impact in Torres del Paine National Park, Chile

Assessment of mountain trails and management measures to mitigate impact in Torres del Paine National Park, Chile

Post-fire invasion in Torres del Paine Biosphere Reserve: the role of seed tolerance to heat

Biological invasions are one of the major causes of biodiversity loss. Anthropogenic alteration in fire regimes has promoted plant invasion in several regions and ecosystems worldwide, especially in those where fires are historically rare. This is the case of the UNESCO Biosphere Reserve Torres del Paine National Park (TPNP), located in southern South America. In this study, we hypothesised that the seeds of native species of the TPNP do not resist fire-related high soil temperatures as do exotic plants, which could facilitate the spread of exotic plant invasion in post-fire environments. To test this hypothesis, we exposed seeds of plant species collected from the TPNP to different heat doses (60°C, 5min; 90°C, 5min; 90°C, 10min; 120°C, 5min) and compared their final germination and viability with those of unheated seeds. The study was conducted on five native species and three aliens inhabiting the TPNP. Almost all the seeds of native species died after exposure to temperatures higher than 60°C, whereas seeds of the alien species resisted higher heat doses. The on-site resistance of the aliens (through fire-tolerant soil seed banks) and the fire sensitivity of native seeds contribute to our understanding on post-fire invasion in the TPNP.

Aquatic biodiversity across a hydroperiod gradient of lakes, ponds, and wetlands in Torres del Paine National Park, Chile

Un entendimiento de como se estructuran las comunidades relativamente pristinas es fundamental para comprender su ecologia y evolucion. En este estudio, examinamos la estructura de las comunidades acuaticas en el Parque Nacional Torres del Paine en la Patagonia Chilena. Utilizando redes de inmersion, cuantificamos la distribucion de anuros de larvas y macro-invertebrados de 81 habitats a lo largo de un gradiente de hidroperiodo (lagos, lagunas, humedales permanentes, humedales semipermanentes y humedales temporales). En comparacion con los estudios realizadosUn entendimiento de como se estructuran las comunidades relativamente pristinas es fundamental para comprender su ecologia y evolucion. En este estudio, examinamos la estructura de las comunidades acuaticas en el Parque Nacional Torres del Paine en la Patagonia Chilena. Utilizando redes de inmersion, cuantificamos la distribucion de anuros de larvas y macro-invertebrados de 81 habitats a lo largo de un gradiente de hidroperiodo (lagos, lagunas, humedales permanentes, humedales semipermanentes y humedales temporales). En comparacion con los estudios realizados en latitudes septentrionales similares, que tienen una gran riqueza de especies y una especializacion en hidroperiodo, los habitats de la Patagonia contenian una riqueza mucho menor con muchos taxones ampliamente distribuidos a lo largo del gradiente de hidroperiodo. En general, la riqueza taxonomica fue mas baja en humedales temporales y lagos, y mas alta en habitats con hidroperiodos intermedios. La causa de esta relacion unimodal fue una pequena disminucion en la prevalencia de todos los taxones en el extremo temporal del gradiente (debido a la desecacion del habitat) pero una exclusion completa de varios taxones en el extremo mas permanente del gradiente (debido a la depredacion de peces). Estos resultados son consistentes con los estudios de Norte America de las comunidades acuaticas y prestan apoyo al efecto hipotetico de la perturbacion en la distribucion de la biodiversidad. El hecho de que la mayor parte de la biodiversidad ocurra en los hidroperiodos temporales e intermedios subraya la importancia de gestionar toda la gama de comunidades acuaticas en lugar de concentrarse unicamente en los lagos mas grandes y mas vistosos.

Sobre la distribución de Glaciares Rocosos en Chile, análisis de la situación y reconocimiento de nuevas localizaciones

La existencia de glaciares rocosos en diversas regiones de Chile ha sido indistintamente reconocida por algunos inventarios y no considerada por otros. Estudios particulares han revelado desde mediados del siglo XX su presencia en diferentes lugares del país. Pero, tanto estos como los inventarios distan aun
 de expresar la real extensión areal de su distribución así como de sus características o del volumen de recurso hídrico que representan. Por tanto, el objetivo de esta contribución es aportar al conocimiento de la real distribución de los glaciares rocosos en Chile. Con este fin se revisan antecedentes sobre la
 existencia de glaciares rocosos en la Cordillera de los Andes de Chile, sobre el conocimiento actual de su distribución zonal y regional, y se ratifica la presencia de ellos en unos casos, y su evolución en otros desde que fueron descritos y cartografiados por primera vez. Finalmente, mediante imágenes satelitales
 se reconocen glaciares rocosos no identificados previamente en las regiones de Atacama, Maule, Aysén y Magallanes, lo que se suma a otros recientemente informados en la región de Valparaíso. De entre ellos, resaltan los glaciares rocosos descubiertos en el Parque Nacional Torres del Paine, entre los 50°56’
 y 50°58’ de latitud S, constituyendo evidencia de los efectos del cambio climático, especialmente de la tendencia térmica regional.
 Como resultado, se establece la presencia de glaciares rocosos con diferentes tipologías y estados evolutivos, en sectores andinos y volcánicos a latitudes menores y mayores que las indicadas en estudios previos, lo que viene a aportar al conocimiento sobre estas expresiones de permafrost en Chile y al inventario nacional de glaciares.

Tendencia de la cobertura vegetacional afectada por incendios en el Parque Nacional Torres del Paine

<p>Torres del Paine National Park (PNTP) is characterized as a representative geographical area of the world’s ecosystems, containing high scenic beauty and wide variety of ecosystems. The aim of this work is to analyze the spatial and temporal trends of vegetation at PNTP using remote images from the Landsat platforms, the MOD13A3 product from the Moderate Resolution Imaging Spectroradiometer (MODIS), coverage maps surface Global Land cover Maps of ESA/CCI 2005 and 2010 and a land cover map of continental Chile of 2014. In addition, the products of Soil Moisture and Ocean Salinity (SMOS) and meteorological data from the Torres del Paine meteorological station were used to analyze the environmental conditions that presented the park while the fire occurred the years 2011-2012. To determine the magni­tude of the changes of vegetation affected by fire at PNTP a nonparametric trend analysis was use with the Normalized Difference Vegetation Index (NDVI) of MODIS from 2002 to 2016 and the Normalized Burn Ratio (NBR) for the fire occurred the year 2005 and the years 2011-2012. The results show that between both fires it is been affected more than 30.000 hectares of the national park, being the “Scrub” and “Forest” coverage the most affected due to the high level of severity and the low regeneration of the burn area (less than 56%). The soil moisture does not exceed 20% m<sup>3</sup>m<sup>-3</sup> before the fire and the rainfall does not exceed 101 mm during the days of fire, which is related to an increase in the probability of propa­gation of the fire. In this work is possible to realize that remote sensing can be used in the fire management to regard the national parks with the objective of preserve and conserve the flora, fauna and scenic beauty of Chile.</p><p> </p>

Los briófitos de la Estancia Cerro Paine, Parque Nacional Torres del Paine, Magallanes, Chile.

Se presenta una lista de plantas no vasculares para la Estancia Cerro Paine, predio particular ubicado en el centro del Parque Nacional Torres del Paine. La lista incluye dos antocerotes, 29 hepáticas y 93 especies de musgos, totalizando 124 especies de briófitos. Se reportan 32 nuevos registros para la provincia de Última Esperanza, 11 para la Región de Magallanes y tres nuevos registros para Chile (Bryum apiculatum, Tortella fragilis y Valdonia microcarpa). Se extienden hacia el norte los límites dedistribución de seis taxones, mientras que los de siete se extienden hacia el sur. Este es el primer listado de briófitos realizado dentro de los límites del Parque Nacional Torres del Paine.

THE STATUS OF THE HOODED GREBE (PODICEPS GALLARDOI) IN CHILE

The status of the Hooded Grebe in Chile has been uncertain since it was first mentioned for the country 25 years ago. Since the first observation, a new set of records has been published elsewhere, but none of them has comprehensively assessed the status of the species in Chile. These publications hypothesize that the species is either a breeding resident, an occasional visitor, or simply a vagrant in southern Chile. In the present article, I collate and discuss all published (and some unpublished) observations of this critically endangered species in Chile, focusing on the temporal distribution of observations and on habitat characteristics. The distribution of records suggests the existence of two different regions where the Hooded Grebe is observed in Chile. The southern area, at both sides of the Strait of Magellan, includes mainly records of putative vagrants during annual movements, while in the northern area, within Torres del Paine National Park and Puerto Natales, the species seems to be a regular summer resident. So far there are no confirmed breeding records for Chile. Although the present information suggests that the Chilean population is very small and not of great importance for the conservation of species, the northern population could represent the last individuals of the presumably extinct Las Vizcachas Plateau’s population of Argentina.

Lenticular Clouds form over the mountains in the Torres del Paine National Park in Patagonia

WeatherVolume 71, Issue 1 p. E5-E5 Inside Cover Photograph Lenticular Clouds form over the mountains in the Torres del Paine National Park in Patagonia First published: 08 January 2016 https://doi.org/10.1002/wea.2692Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume71, Issue1January 2016Pages E5-E5 RelatedInformation

Estimating effective population size of guanacos in Patagonia: an integrative approach for wildlife conservation

By the mid-1900s the guanaco (Lama guanicoe) approached extinction in southern South America due to habitat destruction and hunting. In order to maintain the ecological prominence of this iconic species, as well as assist in the management of populations that are emerging economically while increasing in conservation value, accurate and potentially rapid estimates of effective population size (Ne) (demographic and/or genetic) are essential. Estimates of Ne generally focus on the genetic effective population size; however, we posited that both parameters may be necessary to provide more accurate and timely estimates. Therefore, we examined the performance of three demographic and four genetic estimators of Ne of guanacos in Torres del Paine National Park, Chile, at different years and time intervals between 1987 and 1997. We compared our estimates with census estimates of the adult population size (Nac) during the same time period. Average Ne/Nac ratios of demographic estimates varied between 0.04 and 0.99 of the adult census size. Genetic estimates varied between 0.02 and 0.08 of the adult census size. Based upon group composition and population size (n = 82) of guanacos in 1975, the number of breeding adults was 44 animals. Mean Ne of the single-sample and temporal genetic estimators was 43.1, and 34.3, respectively; estimated Ne of one of the demographic estimators was 41. Our findings suggest that intermittent genetic estimates of Ne (via fecal samples, carcasses, blood collection during capture, and/or other non-invasive methods) can provide crucial information regarding the genetic integrity of increasingly isolated populations of wild South American camelids. Considering the overall performance of these estimators, and differences in how each functions, we recommend an integrative approach using both genetic and demographic estimators, to evaluate Ne for the wild South American camelids and other species with polygynous mating systems.

A Lower Cretaceous ichthyosaur graveyard in deep marine slope channel deposits at Torres del Paine National Park, southern Chile

Remnants of ophthalmosaurid ichthyosaurs recently discovered in the vicinity of the Tyndall Glacier in the Torres del Paine National Park of southern Chile are extremely abundant and well preserved. After three field campaigns to the area, a total of 46 articulated and virtually complete ichthyosaur specimens, both adults and juveniles, were tentatively assigned to four different species of Ophthalmosauridae. Preservation is excellent and occasionally includes soft tissue and embryos. The skeletons are associated with ammonites, belemnites, inoceramid bivalves, and fishes as well as numerous plant remains. The enormous concentration of ichthyosaurs is unique for Chile and South America and places the Tyndall locality among the prime fossil Lagerstatten for Early Cretaceous marine reptiles worldwide. The deposit is Early Cretaceous (Valanginian–Hauterivian) in age and forms part of a monotonous bathyal to abyssal sequence of the Late Jurassic to late Early Cretaceous Rocas Verdes back-arc basin. In this region, the Tyndall ichthyosaur population may have profited from cold upwelling currents that caused abundant life at the shelf edge including masses of belemnites and small fish, the preferred diet of ichthyosaurs. The abundance of almost completely articulated ichthyosaur skeletons in the Tyndall area suggests that some animals fell victim to episodic mass-mortality events caused by turbidity currents traveling downslope through a submarine canyon. They lost orientation, drowned, and were dragged into the deep sea by these turbulent high-energy gravity flows. Their bodies ended up in an oxygen-deficient basin environment where they were immediately embedded by the fine turbidite suspension fallout. The Tyndall ichthyosaur locality thus combines characteristics of both concentration and conservation Lagerstatten.