Southern Chilean Patagonia Research Articles

Systematics ofOligoryzomys(Rodentia, Cricetidae, Sigmodontinae) from southern Chilean Patagonia, with the description of a new species

Systematics of<i>Oligoryzomys</i>(Rodentia, Cricetidae, Sigmodontinae) from southern Chilean Patagonia, with the description of a new species

Integrative taxonomic re-description of Halisarca magellanica and description of a new species of Halisarca (Porifera, Demospongiae) from Chilean Patagonia.

A series of recent expeditions in fjords and canals of Southern Chilean Patagonia allowed the re-collection of Halisarca magellanica Topsent, 1901 and the discovery of a new species, Halisarca desqueyrouxae sp. nov. The material studied was collected at depths ranging from 3 to 30 m at latitudes comprised between 42° and 49°S. Both species share the same habitat and show a morphological plasticity, but differ in their colour. Halisarca magellanica is bright pink to whitish with three morphs whereas H.desqueyrouxae sp. nov. is light brown to beige with two morphs. An extensive investigation in TEM and SEM reveals several differences among cell types with inclusions between both species. Three distinct spherulous cells occur. Type1 is shared by both species, Type 2 is occasional in H. magellanica but absent from H.desqueyrouxae sp. nov. Type 3 is rare in H. magellanica and occurs abundantly in half of the specimens ofH. desqueyrouxae sp. nov. Granular cells are shared by both species but do not occur in all specimens. Microgranular cells are characteristic of H.magellanica. Both species also clearly differ by their endobiotic bacteria. Phylogenetic analysis of cox1 sequences places H. magellanica as a sister group to all other previously published Halisarca species sequences (9.1-9.7% difference) except H. harmelini, while H. desqueyrouxae sp. nov. is placed as a sister group to H. dujardini (2.3% difference).

Carbon flow through the pelagic food web in southern Chilean Patagonia: relevance of Euphausia vallentini as a key species

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 557:91-110 (2016) - DOI: https://doi.org/10.3354/meps11826 Carbon flow through the pelagic food web in southern Chilean Patagonia: relevance of Euphausia vallentini as a key species H. E. González1,2,*, M. Graeve4, G. Kattner4, N. Silva5, L. Castro6,7, J. L. Iriarte2,3,7,8, L. Osmán9, G. Daneri3,7, C. A. Vargas10 1Universidad Austral de Chile, Instituto de Ciencias Marinas y Limnológicas, Valdivia, Chile 2Centro FONDAP de Investigación de Ecosistemas Marinos de Altas Latitudes (IDEAL), Universidad Austral de Chile, Valdivia, Chile 3Centro de Investigación de Ecosistemas de la Patagonia (CIEP), Coyhaique, Chile 4Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany 5Escuela de Ciencias del Mar, P. Universidad Católica de Valparaíso, Valparaíso, Chile 6Departamento de Oceanografía, Universidad de Concepción, Concepción, Chile 7Centro COPAS-Sur Austral, Universidad de Concepción, Concepción, Chile 8Universidad Austral de Chile, Instituto Acuicultura, Puerto Montt, Chile 9The Nature Conservancy, Los Helechos 635, Valdivia, Chile 10Departamento de Sistemas Acuáticos, Facultad de Ciencias Ambientales, Millennium Institute of Oceanography (IMO), and Center for the Study of Multiple-Drivers on Marine Socio-Ecological Systems (MUSELS), Universidad de Concepción, Concepción, Chile *Corresponding author: hgonzale@uach.cl ABSTRACT: The southernmost Patagonian region constitutes a major glaciered area with a high freshwater input loaded with particulate and dissolved matter. We assessed the relevance of the terrestrial (allochthonous) and marine (autochthonous) matter that permeates into the fjord and channel system and their possible impact on the euphausiid-based food web. A research cruise (CIMAR 16) was conducted from 18 October to 13 November 2010 (austral spring) in the area between Magellan Strait and Drake Passage to study the physical-chemical and biological characteristics of the pelagic food web, as well as the main biological processes linked with the food web. The dominance of phytoplankton within the autochthonous fractions of particulate organic carbon (POC) and the high abundance and bacterivory rate shown by the heterotrophic nanoflagellates suggest an interplay between microbial and classical food webs. Euphausia vallentini showed a moderate grazing impact (3% of the gross primary production) and a daily ration of 18.6%, and the fecal pellet production rate corresponded to 24.5% of the ingestion rate. This species removed heterotrophic prey (67.5%) preferentially over diatoms (32.5%), and the ingested diet was mainly dinoflagellates, tintinnids, crustacean nauplii and centric diatoms. Overall, euphausiids fed preferentially on marine matter, which showed a tight link with the pelagic food web. Congeneric species of the genus Euphausia shared the condition of ‘key species’ as they constitute a major carbon and energy flow from lower to higher trophic levels and an important part of the POC flux through their active vertical migration and passive fecal-carbon export. KEY WORDS: Chilean Patagonia · Euphausia vallentini · Pelagic carbon flux · Euphausiid diet Full text in pdf format Supplementary material PreviousNextCite this article as: González HE, Graeve M, Kattner G, Silva N and others (2016) Carbon flow through the pelagic food web in southern Chilean Patagonia: relevance of Euphausia vallentini as a key species. Mar Ecol Prog Ser 557:91-110. https://doi.org/10.3354/meps11826 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 557. Online publication date: September 28, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

Crustacean zooplankton assemblages in inland waters of southern Patagonia (Alacalufes National Reserve), Chile (49-51°S)

The inland water crustacean communities in southern Chilean Patagonia (46-55°S) are characterized by their marked low species number, and many recurrent species among a wide ecological and geographical gradient, that is due to oligotrophy of lakes and lagoons and the fluvial parameters (i.e., high flow velocities) in rivers. The aim of the present study was to describe the zooplankton communities in lakes and respective outflow river estuaries in Alacalufes National Reserve on islands of Chilean southern Patagonia (49-51°S). Species abundance and presence/absence were considered. The results obtained revealed the presence of a low number of species and also multiple sites in which zooplankton was not recorded at all. This is probably due the low zooplankton diversity of cold lakes at these high latitudes and the often turbulent flow of the outflow rivers studied.

Spatial variation in the diet of Patagonotothen tessellata (Pisces, Nototheniidae) from the fjords and channels of southern Chilean Patagonia

The black southern cod, Patagonotothen tessellata, is the most important notothenioid fish species in terms of abundance in southern Chilean Patagonia. However, studies on its trophic ecology are scarce. Here we assessed the spatial variation in the diet of P. tessellata between two localities, one with oceanic influence (Staples Strait) and another with continental influence (Puerto Bories). We used permutation analysis combined with non-metric multi-dimensional scaling to evaluate spatial differences in diet. In addition, generalized additive models were used to identify the most significant environmental, biological and spatial predictors of variability in diet. The black southern cod presents spatial differences in diet composition among contrasting environmental localities. The diet in Staples Strait was characterized by the dominance of the polychaete Platynereis australis, whereas diet in Puerto Bories was characterized by crustaceans, mainly ostracods, gammarids and algae, mainly the filamentous green alga Rhizoclonium sp. and the red algae Polysiphonia sp. Diet composition did not show significant difference between sexes, whereas diet of small, medium and large fish differed to some degree. Smaller-sized P. tessellata were most likely to contain food. Salinity and temperature had significant influence on diet variability, suggesting that P. tessellata showed a greater diversity of prey items in environmental conditions with greater temperature and lower salinity. The results provide evidence of two dietary patterns depending on the type of environment in which they are distributed, highlighting the potential role of the environmental variables on the availability and abundance of potential prey and in structuring diet.

Contribution of allochthonous organic carbon across the Serrano River Basin and the adjacent fjord system in Southern Chilean Patagonia: Insights from the combined use of stable isotope and fatty acid biomarkers

Chilean Patagonia is characterized by an irregular geography involving many islands, peninsulas, channels, sounds and fjords, that prevent direct interaction between oceanic water masses and freshwater river discharges at the head of the continental fjords. In this paper, we evaluate the potential sources and composition of organic matter along the Serrano River basin and the adjacent channels and fjords in Southern Chilean Patagonia (51–52°S), as well as their importance for marine planktonic organisms. In spring of 2009, evidence of C:N ratio, δ13C, δ15N and fatty acids composition in particulate organic carbon (POC), surface sediment, soil, plankton, and vegetal tissue, as well some physical and chemical characteristics (i.e. salinity, dissolved oxygen, NO3−, NH4+, PO4−3, Si(OH)4), were measured in samples collected during the CIMAR 14 Fiordos oceanographic cruise. Significant differences in δ13C-POC were found between the terrestrial and marine environments but not within fjord stations. Along the fjord region, the high C:N ratio and depleted δ13C values in POC samples suggest that particulate organic matter (POM) in the upper level of the water column (0–10m depth) is supported by different sources. Terrestrial organic carbon exported by rivers may constitute a significant subsidy, up to 70% based on two end-member mixing model, to the fjord ecosystem. Furthermore, terrestrial carbon might account for a significant percentage of the zooplankton body carbon, estimated both by using isotopic (∼24–61%) and fatty acid analysis (∼14–61%). Isotopic analyses in marine sediment samples suggest that POC seems to be decoupled from terrestrial-influenced surface sources at the fjord stations, and the contribution of surrounding vegetation seemingly unimportant for carbon export to the benthos. Local hydrographic and geomorphological characteristics might determine the presence of oceanographic frontal zones, which in turn might explain differences in carbon sources found between POM and the surface sediments.

Calidad de los sedimentos marinos entre el Estrecho de Magallanes y el Cabo de Hornos (Patagonia chilena) en función de pruebas de toxicidad

The southern Chilean Patagonia is being incorporated into the productive activity through their water bodies applied in aquaculture. This makes it necessary ...

On the geographic distribution of Boeckella brevicaudata (Brady, 1875) (Copepoda, Calanoida) and its species associations in seasonal ephemeral pools in the Magallanes region (53°S, Chile)

The distribution of crustaceans of inland waters in southern Patagonia is characterized by the presence of sub-Antarctic and southern South American species. The aims of the present study were to study the geographical distribution of the calanoid copepodBoeckella brevicaudata(Brady, 1875) and the community structure of the zooplankton assemblages in which this species occurs. This last purpose was approached by applying null-models analyses based on species co-occurrence and niche-sharing. The species itself inhabits sub-Antarctic islands as well as southern South America. The results of the co-occurrence null model analysis revealed that the communities with this species have no regulating factors, whereas the niche overlap null model analysis revealed that these species share the same ecological niche. We thus found low abundances for all species, with specifically lowB. brevicaudataabundance, at low mineral contents of the water. The results obtained were similar among sites in southern Argentinean and southern Chilean Patagonia, and on sub-Antarctic islands of which data were available.

Trailing hounds vs foot snares: comparing injuries to pumas Puma concolor captured in Chilean Patagonia

We compared injuries resulting from two different capture methods, i.e. trailing hounds and foot snares, for pumas Puma concolor in a mixed landscape with open grasslands and limited ‘retreat’ habitat in southern Chilean Patagonia. Injury scores were not significantly different for the two methods, although the small sample size for captures made with snares likely influenced our findings. Based on a potential range of 0‐400, the mean injury score for pumas caught using hounds was 56.3 ± 132.9 (SD). The mean puma injury score for five animals caught in snares was 3.8 ± 1.1. Pumas were injured and/or killed in 86% of captures using trailing hounds. The number of hounds used in a capture attempt did not predict the likelihood of successfully catching a puma (P = 0.35), whereas there was a strong relationship between the number of dogs and the likelihood of a fight with the puma (P &lt; 0.0001). The odds ratio calculation predicted a 14.7% increase in the likelihood of a fight between puma and hounds with the addition of each dog to the chase. Our results highlight the potential risks associated with trailing hounds in open landscapes. We suggest guidelines for the use of hounds in predominantly open landscapes, and that alternative capture methods such as foot snares should be considered as a potentially safer alternative. Lastly, we make recommendations for the development of injury assessment systems more relevant to catch‐and‐release research.

Magellanic Wetlands: More than Moor

Magellanic wetlands in the Patagonian steppe are unique habitats from the point of view of conservation and agriculture. Little is known about their environmental characteristics and plant communities. Our aim was to describe vegetation variability to improve current classifications and reveal environmental factors correlated with vegetation variability in the meadow wetlands (vegas) of southern Chilean Patagonia and Chilean Tierra del Fuego. Five vegetation types resulted from TWINSPAN classification and subsequent interpretation, based on which four new associations were delimited: Magellanic acidic marshes – the Scirpo cernui-Calthetum sagittatae, Magellanic alkaline wet grasslands – the Samolo spathulatae-Azorelletum trifurcatae, Magellanic tall sedge marshes – the Carici maclovianae-Agrostietum stoloniferae, and Magellanic pastures – the Hordeo lechleri-Trifolietum repentis. The fifth vegetation type, saline wetlands, is the rarest and so far the least known community. Magellanic wetland vegetation forms a gradient from short saline marshes to tall graminoid-dominated communities. They reflect a major soil gradient of pH and organic matter content, along with the content of major elements (N, P, K, Fe, Al). Other important factors are ground water regime and grazing intensity.

Species co-occurrences based on a presence/absence null model for Copepoda and cladocerans in Patagonia and Tierra del Fuego lakes and ponds

The zooplankton assemblages in southern Chilean Patagonia are characterized by calanoid dominance and low species number that is observable under oligotrophic status and wide conductivity values, whereas at mesotrophic status the daphnids are dominant with high species number, and finally at hyper-saline environments halophilic species such as Artemia persimilis and/or the calanoid Boeckella poopensis predominate. In the present study data of different lakes and ponds between 45-53° S were analyzed, with the aim to determine potential structures at different sites. For this purpose a null model based in guild structure was applied, considering each guild a different kind of water body (lake, small lake, permanent pond, ephemeral pond, and saline lake). The results revealed in two simulations that guild are structured. These results are similar with other descriptions on the basis of null models that revealed a random pattern of species associations for similar ecosystems due to many species repeated in all or practically all studied sites or similarities of ecological features. Ecological and biogeographical topics were discussed.

New evidence of the sabertooth cat Smilodon (Carnivora: Machairodontinae) in the late Pleistocene of southern Chilean Patagonia

Surpatagonia es particularmente rica en mamiferos finiplesitocenos, particularmente camelidos, equidos y xenartros. Los carnivoros, por su parte, se encuentran representados en menor numero en el registro paleontologico. Dentro de estos, el genero Smilodon, es de particular interes debido a que su presencia en la region no ha sido convincentemente demostrada. En este trabajo presentamos evidencia dental que permite confirmar la presencia de Smilodon populator (Lund) en la region. Esta evidencia corresponde al registro mas sureno de este taxon y al paso final en la colonizacion de America del Sur despues del Gran Intercambio Biotico Americano. Un fechado radiocarbonico directo AMS indica que los restos de Patagonia del Sur corresponden a los registros mas tardios para este genero en el subcontinente.

Calibration of glacier volume–area relations from surface extent fluctuations and application to future glacier change

AbstractThe volume- and area-change evolution of glaciers can be obtained by employing the volume–area scaling approach during mass-balance modelling. This method usually requires information on the initial surface area and ice volume to adjust the volume–area relation to the specific ice body. However, absolute volumetric data on glaciers are very rare, so the applicability of volume–area scaling is limited. In order to use volume–area scaling on glaciers for which only limited information is available, a new method is presented to calibrate the volume–area relation without prior knowledge of this relation by using glacier extent information from different times. To validate the method and illustrate its practicability, we model the range of probable future changes in ice volume and surface area of ‘Glaciar Noroeste’, an outlet glacier of Gran Campo Nevado ice cap, southern Chilean Patagonia, during the 21st century, based on IPCC SRES scenarios B1 and A2.

Osteometría de Vicugna vicugna Molina, 1782 en el Pleistoceno final de Patagonia meridional chilena: Implicancias paleoecológicas y biogeográficas

Se presenta un análisis osteométrico uni y multivariado con los materiales fósiles -principalmente huesos cortos y falanges- de Vicugna sp. del yacimiento Cueva Lago Sofía 4 (13500 – 11000 AP), ubicado en la provincia de Última Esperanza (Región de Magallanes, Chile). Los resultados indican que los elementos analizados poseen un tamaño compatible con los registrados para Vicugna vicugna, no superando en ningún caso a los especímenes conocidos para Vicugna gracilis del Pleistoceno de la región Pampeana. Esto confirma la información morfológica y de ADN antiguo que indicaba la presencia de Vicugna vicugna en la Patagonia meridional chilena. Se discuten los resultados en términos taxonómicos, biogeográficos y paleoecológicos sugiriendo que la presencia de este taxón fuera de su rango actual de distribución se debió a las condiciones ambientales compartidas entre la Puna y Patagonia austral durante la transición Pleistoceno-Holoceno. La extinción de V. vicugna se habría debido al impacto de los cambios climáticos ocurridos al inicio del Holoceno producto de su dieta pastadora y etología no migratoria y territorial, a lo que se habría sumado una caza por parte de depredadores humanos y no humanos.

Branchinecta gaini Daday, 1910 (Branchiopoda, Anostraca) as a bioindicator of oligotrophic and low conductivity shallow ponds in southern Chilean Patagonia

The south of Patagonia is characterized by its semi-arid weather and numerous small, temporary and permanent shallow ponds. The aquatic crustaceans of these water bodies are characterized by their endemism and species richness. The present study was done in the surroundings of Punta Arenas (53°S, Chile), and included six shallow ponds. Samples for conductivity, total dissolved solids, chlorophyll, and crustacean zooplankton as well as littoral species of crustacea were collected. Our study revealed that Branchinecta gaini Daday, 1910 occurred at low conductivity (0.55 mS/cm), and low total dissolved solids (0.28 g/l) and chlorophyll (2.70 μ g/l) concentrations, such compared to sites without fairy shrimp populations, that had significantly high conductivity (3.58 mS/cm), and high total dissolved solids (1.80 mg/l) and chlorophyll (12.80 μ g/l) concentrations. The results partially agree with the first descriptions of Patagonian water bodies that indicated the presence of fairy shrimps in low conductivity waters. The observations of the presence of B. gaini and other associated microcrustaceans are similar to descriptions of unpolluted water bodies in Antarctica, and those results would support the observations of the present paper. Other reports on fairy shrimp habitats mentioned a wide range of both salinity and trophic status. Other ecological and biogeographical topics on fairy shrimps are also discussed. La zona sur de la Patagonia se caracteriza por su clima semi-arido, y presenta numerosas lagunas poco profundas, ya sea superficiales o permanentes. La fauna acuatica de estos ecosistemas se caracteriza por su alto endemismo y riqueza de especies. El presente estudio se realizo en las cercanias de la ciudad de Punta Arenas (53°S, Chile), y este incluyo seis pequenas lagunas superficiales. Se colectaron muestras para analisis de conductividad, solidos totales disueltos, clorofilay crustaceos zooplanctonicos y litorales. El presente estudio revelo que la especie Branchinecta gaini Daday, 1910 fue observada en condiciones de baja conductividad (0,55 mS/cm), solidos totales disueltos (1,80 g/l) y baja concentracion de clorofila (2,70 μ g/l); valores notablemente bajos en cuanto a la conductividad (3,58 mS/cm), solidos totales disueltos (1,80 g/l) y concentracion de clorofila (12,80 μ g/l) observados para sitios sin poblaciones de Branchinecta . Los resultados observados concuerdan parcialmente con las primeras descripciones para la zona sur de la Patagonia. La presencia de B. gaini y otros microcrustaceos asociados es similar a las descripciones para cuerpos de aguas continentales pristinos de la Antartica. Los resultados publicados para otros biotopos de camarones duende denotan un amplio gradiente de salinidad y condiciones troficas. Se discutieron topicos ecologicos y biogeograficos.

Influence of trophic status and conductivity on zooplankton composition in lakes and ponds of Torres del Paine National Park (Chile)

The Torres del Paine National Park is located in the southern Chilean Patagonia. This park has numerous and heterogeneous lakes and ponds with different trophic status and zooplankton composition. The aim of this study was to analyze the influence of trophic status and conductivity on zooplankton assemblages in lakes and ponds within the Torres del Paine National Park. The water bodies described in the present study were previously classified in three groups. The first group consisted of large, deep and oligotrophic lakes with fish populations, low zooplankton species diversity and high predominance of calanoid copepods of small body size. The second group contained small mesotrophic lakes with fish populations and relatively high predominance of small sized daphnids. The third group consisted of fishless ponds of different trophic status, wide conductivity gradient and with zooplankton species of relatively large body size. The results show that Daphnids abundance was directly related to chlorophyll-a concentration and inversely associated with conductivity. Calanoids abundance was also directly associated with conductivity.

Tree-ring growth patterns and temperature reconstruction from Nothofagus pumilio (Fagaceae) forests at the upper tree line of southern Chilean Patagonia

Nothofagus pumilio (Poepp. et Endl. Krasser) es una especie caducifolia que domina el limite arboreo superior de los Andes de Chile y Argentina entre los 35o 36' y 55o 31' S. En este trabajo describimos el desarrollo de 21 cronologias de ancho de anillos de N. pumilio para su rango mas austral de distribucion (51-55o S) en Chile, asi como el analisis de su relacion con el clima. Diez de las cronologias de ancho de anillos estudiadas muestran una tendencia al incremento y/o crecimiento sobre el promedio a partir de aproximadamente 1960 hasta 1996, lo cual coincide con un incremento sostenido en las temperaturas mostrado por los registros instrumentales de la Patagonia austral. Otra caracteristica particular del crecimiento de los arboles es un notable ciclo de cerca de 7 anos presente en tres de los sitios de estudio en la Isla Navarino, el area de estudio mas austral estudiada por nosotros (55o S). Estos dos patrones de crecimiento, representan los principales modos de variacion de los registros de anillos de crecimiento de N. pumilio en la Patagonia austral de Chile, y explican respectivamente el 14 y 28 % de la varianza total. Sobre la base de la correlacion positiva que se verifica entre el crecimiento arboreo y la temperatura en varios de los sitios de estudio analizados en este trabajo, reconstruimos las variaciones de las temperaturas minimas anuales de Punta Arenas para el periodo 1829-1996. La reconstruccion muestra que durante la mayor parte del siglo 19 las temperaturas minimas anuales permanecieron por debajo del promedio, aumentando a valores que fluctuaron en torno a la media durante el periodo 1900-1960, seguido por una clara tendencia sobre la media para el periodo posterior a 1963