Universidad de Magallanes
Not a member yet
1947 research outputs found
Sort by
Woody legacies of railroad ties from the Southern Atacama Desert used to strengthen Nothofagus obliqua tree-ring chronologies from Northern Patagonia
No full textDuring the late Nineteenth and Twentieth centuries there was an intense exploitation of the long-lived Nothofagus obliqua forests in the temperate region of South America due to the quality of their hardwood. This exploitation resulted in degradation of this Northern Patagonian ecosystem with severe biodiversity implications. This also has prevented the development of multicentury N. obliqua tree-ring width chronologies, with implications for regional environmental and paleoclimatological studies. The large-scale manufacturing of railroad ties distributed across Chile drove part of this exploitation. This study evaluated the use of this cultural material from abandoned tracks preserved in the southern Atacama Desert to strengthen the existing N. obliqua tree-ring network in Patagonia. We dated this historical wood using classical crossdating ring-width methods corroborated with wiggle matching of radiocarbon series from railroad tree-rings using the hemispheric 14C curve. Correlation analysis with climate data and paleoclimate field reconstructions shows a clear hydroclimate signal contained in the resulting regional tree-ring record with a consistent spatial pattern across northern Patagonia. The dendrochronological use of railroad ties preserved in the Atacama Desert opens a new avenue for dendroclimatic studies and highlights its heritage importance as a past environmental archive in southwestern South America
Sobre la presencia de Thaumastocoridae (Hemiptera: Heteroptera) en Rapa Nui
No full textThe presence of true bug family Thaumastocoridae is recorded and discussed for the first time from the Oceanic Easter Island, Chile; with the species Thaumastocoris peregrinus Carpintero & Dellapé, 2006. Specimens were collected on Eucalyptus sp. Comments on the status of the invasion are provided
Impact of land transformation, management and governance on subjective wellbeing across social-ecological systems
No full textRecognizing and understanding the subjective wellbeing (SWB) of individuals is essential for designing effective policies that promote human development and the sustainable management of social-ecological systems (SES). This is particularly important for smallholders, critical stewards of biodiversity who face acute livelihood challenges. This article explores how smallholders inhabiting tropical dry forests in Mexico perceive their SWB and how it changes across a spectrum of SES that undergo different land transformations, management intensities, and governance dynamics. Our aims are to identify the dimensions of SWB that smallholders perceive, understand how these dimensions change across SES, and examine how smallholders' perceptions of fulfilled material and non-material dimensions vary across SES. We analyzed the content of 25 in-depth interviews with farmers and identified 48 SWB items belonging to six categories: (1) social capital, (2) economic capital, (3) agency, (4) nature, (5) pleasant non-work activities, and (6) governmental services, and two additional dimensions referred to obstacles and enablers. We found two prevailing visions of SWB: 'living well' prevails especially in areas with communal governance and medium management intensity, and 'need to earn more' prevails in areas with individual governance and intensified land management. As management is intensified and governance fosters individualism, the lower the self-perceived material and non-material satisfaction. We discuss the different SWB found per SES, as well as strategies that can foster smallholder's SWB and SES dynamics that can motivate different conservation goals and sustainable uses of nature, especially in biodiverse areas
Habitat Selection of Sympatric Lontra felina and L. provocax in Chilean Patagonia: Toward Sustainable Management
No full textUnderstanding habitat use in sympatric species is key to informing conservation efforts. Lontra felina and L. provocax are semi-aquatic mustelids commonly known as South American marine and southern river otters, respectively, that occupy contrasting coastal environments in southern Chile. We investigated habitat characteristics associated with sightings of both species in the Raúl Marín Balmaceda Multiple Use Protected Area, northern Chilean Patagonia. Our results show L. felina is restricted to exposed, steep rocky shores with sparse vegetation and intertidal belts dominated by Durvillaea antarctica and Lessonia spp., while L. provocax was found to be associated with sheltered, forested margins and estuarine areas dominated by Macrocystis pyrifera and other meadow-forming algae. Records did not show coexistence of both species in the same location; therefore, it is concluded that they exhibit a sympatric but non-syntopic pattern
Adaptive response in waterbirds after mink introduction in subantarctic ecosystems
No full textGround-nesting birds on islands are particularly vulnerable to the introduction of terrestrial carnivores because the former often lack defensive behaviors, displaying high levels of naivety under absence of co-evolutionary history. Relatively few studies have addressed such potentially adaptive responses. In this study, we investigated whether two bird species, upland geese (Chloephaga picta) and flightless steamer ducks (Tachyeres pteneres) have modified their nesting strategies as a response to the novel predatory pressure imposed by the invasive American mink (Neogale vison) on Navarino Island, southernmost Chile, since its arrival in 2001. We used discriminant analysis and pairwise Wilcoxon tests to compare two data sets (n = 140 nests in total) regarding the macro- and microhabitat where nests were placed, separated by a time span of 15 years. We found that upland geese currently nest in less dense habitat (macrohabitat), hide their nests in shorter shrubs with lower top and side cover (microhabitat), and breed later in the season. In contrast, flightless steamer ducks retain almost the same nesting habitat characteristics. We discuss our findings in the context of ecological and evolutionary restrictions to adaptation
Effects of neuromuscular training on proprioception and muscular reaction time in older woman: Randomized controlled trial
No full textBackground this study aimed analyze the effects of a neuromuscular training program compared to a multicomponent training program on proprioception and muscle reaction time in older woman. Material and methods Randomized controlled trial, included 54 older women randomized into 3 groups: multicomponent group (MCG), neuromuscular group (NMG), and control group (CG). Proprioception was assessed using the active repositioning test in the shoulder, elbow, hip, and knee joints. The muscular reaction time of the peroneus longus, tibialis anterior, and gastrocnemius medialis were evaluated. MCG carried out a multicomponent training program and, NMG realized neuromuscular training program plus the multicomponent training. Results A significant time x group interaction was observed in proprioception the shoulder joints (F = 7.57; p = 0.003; eta p(2) = 0.255), hip joints (F = 10.2; p = < 0.001; eta p(2) = 0.258) and knee (F = 7.12; p = 0.004; eta p(2) = 0.244) and reaction time of the peroneus longus (F = 13.7; p = < 0.001; eta p(2) = 0.378), tibialis anterior (F = 8.14; p = 0.002; eta p(2) = 0.246) and gastrocnemius medial (F = 7.86; p = 0.003; eta p(2) = 0.263). Multiple comparisons showed that there are significant improvements between the pre-and post-assessment of the NMG in proprioception and muscle reaction time. Conclusions Neuromuscular training program enhances the effects of multicomponent training and should be included in the physical activity programs of older peopl
Human-nature relationships through the lens of reciprocity: Insights from Indigenous and local knowledge systems
No full textIn the context of climate change, biodiversity decline and social injustice, reciprocity emerges as a way of living and being in this world that holds transformative potential. Concepts of reciprocity vary and are enacted in specific cultural practices grounded in Indigenous and local knowledge systems. This editorial synthesises first-hand evidence of how practising reciprocity can result in positive reciprocal contributions between people and nature. It also offers a theoretical justification of why considering reciprocity can lead to more equitable, inclusive and effective conservation and sustainability policy and practices, contributing to curving the colonial baggage of academic inquiry and development action. Nurturing reciprocal relations between people, especially between academics and Indigenous Peoples and local communities, is a necessary first step to identifying pathways whereby living in harmony with nature can be achieved. En el contexto actual de cambio climático, declive de la biodiversidad e injusticias sociales, la reciprocidad emerge como una forma de vivir y ser en este mundo con potencial transformador. Los conceptos de reciprocidad son diversos y se materializan en prácticas culturales específicas basadas en sistemas de conocimiento Indígenas y locales. Este artículo editorial sintetiza evidencia de cómo las prácticas de reciprocidad pueden dar lugar a contribuciones recíprocas positivas entre las personas y la naturaleza. El artículo también ofrece una justificación teórica de por qué la consideración de la reciprocidad puede conducir a políticas y prácticas de conservación y sostenibilidad más equitativas, inclusivas y eficaces, contribuyendo a reducir el bagaje colonial de la investigación académica y las estrategias de desarrollo sostenible. Fomentar las relaciones recíprocas entre personas, especialmente entre académicos y pueblos Indígenas y comunidades locales, es un primer paso necesario para identificar vías que permitan vivir en armonía con la naturaleza
Oceanic phytoplankton structure off western Patagonia during the austral summer: Implications for harmful algal blooms
No full textChanges in phytoplankton composition and abundance are controlled by multiple factors, including physical forcing and nutrient stoichiometry. This study seeks to assess the interplay between the environmental and biogeochemical conditions in shaping the phytoplankton community structure in open ocean waters off western Patagonia. For this purpose, we used biological, hydrographic, and chemical data measured aboard the R/V Mirai during the austral summer of 2017, combined with remote sensing and reanalysis products. Although no first-order predictive relationships were found between the environmental and biological data, the results showed a latitudinal gradient of the phytoplankton structure, favoring maximum abundances of diatoms (similar to 10x10(4) cells L-1) in the northern area (similar to 43-48 degrees S) characterized by high stratification and freshwater content. The high diatom abundances of Thalassiosira spp., Chaetoceros spp., Pseudo-nitzschia cf. australis and Pseudo-nitzschia cf. pseudodelicatissima taxa in this area results in a nutrient content decreases (nitrate < 9 mu mol kg(-1), phosphate < 0.9 mu mol kg(-1), silicic acid < 1.5 mu mol kg(-1)), and low N:Si (<8) and N:P (<10) ratios. Nonetheless, the total dinoflagellates abundance was equal to or higher than those of diatoms (similar to 10.2x10(4) cells L--(1)) throughout most of the sampling region. Specifically, maximum abundances (similar to 6.3x10(4) cells L--(1)) of Karenia spp. were found in the north under the freshwater influence from the Gulf of Penas, where the highest ammonium:nitrate ratio (similar to 4 to 11.5) was recorded. In contrast, high dinoflagellate abundances of Azadinium spp. were found in the south (similar to 48-55 degrees S), where an increase of nutrient content (nitrate similar to 12 mu mol kg(-)(1), phosphate similar to 1 mu mol kg(-)(1), ammonium similar to 0.4 mu mol kg(-)(1)), and high N:Si and N:P ratios (similar to 35 and similar to 12) were observed. This study highlights a major presence of potentially toxic phytoplankton species in the oceanic zone off northern Patagonia under conditions of strong latitudinal and cross-shore gradients in nutrient content and salinity, related to the interplay between oceanic water masses and freshwater input
Human footprint alters morphological traits and gut microbiome assembly of Antarctic sea urchins
No full textAntarctica has experienced a growing human footprint in recent decades, driven by the intensification of scientific, logistic, and tourism activities. While the effects of human activities on Antarctic ecosystems are increasingly documented, their impact on developmental stability and microbiome of Antarctic species remains largely unexplored. Here, we compared two contrasting coastal sites in Fildes Bay, King George Island: one close to a research station, and the other within a protected area. Trace element concentrations in sediments were analyzed by ICP-MS. The Antarctic sea urchin Abatus agassizii was chosen as a model organism to assess the effects of human footprint, integrating two key aspects: (i) the sea urchin's fluctuating asymmetry (i.e. small random differences between specimen sides), as an indicator of developmental stress (n = 60), and (ii) its gut microbiome composition and assembly processes, through 16S rRNA amplicon sequencing (n = 26). Arsenic (As) and potassium (K) were significantly enriched in the sediment of the anthropogenically impacted site compared to the protected area. Higher levels of fluctuating asymmetry and shape variation were detected in A. agassizii individuals from the contaminated site, accompanied by alterations in gut microbiome, including destabilized cooccurrence network, increased variability and stochasticity, and enrichment of bacterial taxa typically associated with hydrocarbon exposure. These results highlight the potential of anthropogenic pollution to disrupt critical characteristics of a key sediment bioturbator such as A. agassizii. Abatus sea urchins may serve as valuable bioindicators for monitoring human-induced stress, guiding conservation efforts to limit the human footprint and protect these highly sensitive marine Antarctic ecosystems
Seaweed cultivation under threat: the impact of epiphytes on Gracilaria chilensis cultivation in Chile
No full textThe cultivation of Gracilaria chilensis ("pelillo") is an important aquaculture industry in Chile, but the growth of epiphytic algae threatens its productivity. This study investigates the spatio-temporal dynamics of epiphytic algae in G. chilensis farms in the Pudeto and Maullín rivers, Los Lagos Region, Chile, from 2017 to 2021. Seasonal sampling assessed epiphyte biomass, taxa richness, and their impact on the seaweed's growth. A total of 21 species of epiphytes were identified, with 14 found within the sampling quadrats and seven outside. Significant seasonal fluctuations in wet biomass and taxa richness were observed, with the highest epiphyte load recorded during the summer months, particularly in the Pudeto river. Here, the epiphyte load was consistently higher than Maullín's, which showed no significant annual changes in 2017 but a notable increase in epiphyte biomass by 2021, even during winter. Canonical Correspondence Analysis (CCA) revealed that environmental factors, such as salinity, significantly influenced epiphytic assemblages. Lower salinity sites promoted Chaetomorpha linum, Grateloupia sp., and Ulva sp., while more marine conditions supported Polysiphonia sp. and Ulva sp. These findings highlight the need for targeted management strategies to mitigate epiphyte proliferation, ensuring the sustainability of G. chilensis farming. Effective intervention measures, including improved farming practices and environmental monitoring, are critical to reducing economic losses and maintaining the viability of this important aquaculture resource