Maldonado A.,University of La Serena |
Mendez C.,University of Chile |
Ugalde P.,Pasaje Angelmo 2373 |
Jackson D.,University of Chile |
And 2 more authors.
Journal of Quaternary Science | Year: 2010
The brief, terminal Pleistocene archaeological site at Santa Julia (SJ, 31° 50' S; 71° 45' W) is the only one with fluted projectile preforms and megafauna consumption known from the Chilean semiarid coastline. Here, we present the climatic history at SJ during the early Holocene reconstructed from pollen and charcoal analyses spanning 13.2-8.6 ka (=103 calibrated 14C yr BP). Elevated charcoal concentrations confirm human activity by 13.2 ka. Human occupation decreased in intensity and charcoal practically disappears from the record after 10.6 ka, followed by wetland expansion at SJ between 10.5 and 9.5 ka. Local dominance of coastal shrubland reveals that dry phases occurred between >11.2-10.5 and 9.5-9.0 ka. Overall, these findings imply that by modulating available resources at both local and landscape levels climate change may have played an important role in explaining the peopling of semiarid coastal Chile. Copyright © 2010 John Wiley & Sons, Ltd.
Driscoll D.A.,National Environmental Research Program Environmental Decisions Group |
Driscoll D.A.,Australian National University |
Catford J.A.,National Environmental Research Program Environmental Decisions Group |
Catford J.A.,Australian National University |
And 13 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2014
Agricultural intensification is critical to meet global food demand, but intensification threatens native species and degrades ecosystems. Sustainable intensification (SI) is heralded as a new approach for enabling growth in agriculture while minimizing environmental impacts. However, the SI literature has overlooked a major environmental risk. Using data from eight countries on six continents, we show that few governments regulate conventionally bred pasture taxa to limit threats to natural areas, even though most agribusinesses promote taxa with substantial weed risk. New pasture taxa (including species, subspecies, varieties, cultivars, and plant-endophyte combinations) are bred with characteristics typical of invasive species and environmental weeds. By introducing novel genetic and endophyte variation, pasture taxa are imbued with additional capacity for invasion and environmental impact. New strategies to prevent future problems are urgently needed. We highlight opportunities for researchers, agribusiness, and consumers to reduce environmental risks associated with new pasture taxa. We also emphasize four main approaches that governments could consider as they build new policies to limit weed risks, including (i) national lists of taxa that are prohibited based on environmental risk; (ii) a weed risk assessment for all new taxa; (iii) a program to rapidly detect and control new taxa that invade natural areas; and (iv) the polluter-pays principle, so that if a taxon becomes an environmental weed, industry pays for its management. There is mounting pressure to increase livestock production. With foresight and planning, growth in agriculture can be achieved sustainably provided that the scope of SI expands to encompass environmental weed risks.
News Article | December 29, 2015
Where on Earth is the purest water found? A new scientific study concluded that the world's purest water can be found in fresh waters of Puerto Williams in southern Chile. A team of scientists from the University of North Texas (UNT), University of Magallanes and Institute of Ecology and Biodiversity of the University of Chile, analyzed water samples taken for more than 10 days from several natural waterways near Puerto Williams. They wanted to determine the quality of freshwater in that region in the Chilean Patagonia, near the tip of South America. "Our results confirm that these waters are clean, the cleanest waters existing on the planet," said Dr. Guido F. Verbeck, principal investigator and director of UNT Laboratory of Imaging Mass Spectrometry. "In fact, the instruments we use to study the samples can detect chemical compounds in the water up to two parts per million, and here, we did not detect anything," he added. The samples of water needed were collected from several sources of fresh water in the area including Bronzes River, Ukika River, Laguna Los Guanacos and Bass River. With the use of high-resolution laboratory equipment, the samples were analyzed and the scientists concluded that fresh water in this area is the purest in the whole world. The researchers said that the study is highly important for the world because water is one of the Earth's most essential compounds because of its scarcity. This discovery could place the Cape Horn Biosphere Reserve, one of the world's last remaining wilderness areas, as a natural laboratory. "So far there are no records of other sites as clean as this, and that has to do with its geographical location, below latitude 55 degrees south, out of the air currents that carry industrial pollutants generated in the northern hemisphere," explained Tamara A. Contador, from the University of Magallanes. According to the Director of the Antarctic Biocultural Conservation Program, Ricardo Rozzi, the air and water in the area "have a purity and an ecosystem that existed before the Industrial Revolution". Aside from Puerto Williams, the study found that pure water was also found in Torres del Paine National Park, also a part of Magallanes region and in southeastern China, Upstate New York and western Australia. Pure water or unpolluted water is already scarce worldwide. In fact, of the world's available water, only 0.003 percent is unpolluted. Puerto Williams is a Chilean town, located on Isla Navarino facing the Beagle Channel and it is located in the Magallanes region. It is located at 3,551 kilometers (2,206 miles) south of Santiago at the country's extreme southern tip. With only a population of nearly 2,500 people, it is dubbed as the southernmost city in the world. Its name came from Captain John Williams, a person who founded Fuerte Bulnes on the Brunswick Peninsula in 1843. Its main source of income is through tourism. It offers several trails for days of hiking and backpacking trips in the mountains. This port is a major agenda for scientific studies associated with Antarctica.
Rodriguez-Echeverria S.,University of Coimbra |
Armas C.,CSIC - Estación Experimental De Zonas Áridas |
Armas C.,Institute of Ecology and Biodiversity |
Armas C.,University of La Serena |
And 4 more authors.
Journal of Ecology | Year: 2013
Plant-plant facilitation is an important driver of plant diversity, which in turn maintains ecosystem multifunctionality and can buffer some negative effects of climate change. Facilitation is classically attributed to the amelioration of environmental extremes and resource availability. Integrating below-ground biota into the positive plant interactions framework should provide a more realistic understanding of this process, enabling us to gain insights into the dynamics of below-above-ground communities. We tested the effect of below-ground biota on the performance of a plant community and of individual species using soil extracts from the understorey of a benefactor plant species and adjacent open spaces. Soil bacteria from extracts and experimental microcosms were analysed using pyrosequencing. Soil biota had a significant effect on the abundance, growth, functional traits and reproductive output of beneficiary plant species through processes that are independent of the direct influence of the benefactor species. Different soil bacterial communities were associated with the benefactor species, the individual beneficiary plant species and the plant community, revealing complex below-above-ground links between plants and soil microbiota. Synthesis. The below-ground biota cultivated by benefactor plant species play a fundamental role in positive interactions between plant species contributing to the preservation of diversity and the evolution of plant communities. © 2013 British Ecological Society.
Astorga-Espana M.S.,University of Magallanes |
Mansilla A.,University of Magallanes |
Mansilla A.,Institute of Ecology and Biodiversity
Journal of Applied Phycology | Year: 2013
In order to promote the use of sub-Antarctic macroalgae as food, four species of marine macroalgae: Macrocystis pyrifera, Durvillaea antarctica, Pyropia columbina, and Callophyllis variegata were studied for their nutritional value. They were collected monthly between October and December 2012 throughout the Strait of Magallanes, sub-Antarctic Chile. The chemical composition, including carbohydrates, proteins, lipids, and vitamins A and C, and the macronutrient, mineral, and fatty acid content were examined. Ash (15.1-34.1 %) and soluble fiber (26.5 to 40.3 %) were the most abundant in these species. Presence of protein was moderate (8.2-25.0 %), with red alga (C. variegata) having the highest value on dry weight (dw). All algal species had lipid contents of less than 5 % dw. Maximum carbohydrate content was observed in P. columbina (9.5 % dw). Potassium was the most abundant essential element found in M. pyrifera (8.51 % dw), while P. columbina was found to be richest in iron (305.5 ± 5.5 μg g-1 dw) and C. variegata showed the highest contents of Cu (17.4 ± 0.7 μg g-1 dw). The most abundant saturated fatty acids were palmitic (C16:0) and myristic acid (C14:0), with values ranging from 4.33 to 9.22 %. The most abundant monounsaturated fatty acid was oleic acid (C18:1ω9). The highest levels of polyunsaturated fatty acid were observed for arachidonic (20:4ω6) and eicosapentaenoic acid (C20:5ω3) or EPA. © 2013 Springer Science+Business Media Dordrecht.
Mansilla A.,University of Magallanes |
Mansilla A.,Institute of Ecology and Biodiversity |
Avila M.,Arturo Prat University
Brazilian Journal of Pharmacognosy | Year: 2011
The exploitation of seaweeds in Chile has been carried out for more than 60 years. More recently, seaweeds have been used for the production of alginate, agar and carrageenan, agricultural fertilizers and industrial aquaculture (feed for abalone and sea urchins), increasing the added value of this natural resource. In the Magellan Region (56°S), the giant kelp Macrocystis pyrifera (L.) C. Agardh presents the most extensive kelp forest, reaching a biomass of approximately 12 kg.m-2. Recent studies have shown potential benefits from adding M. pyriferaderived flour to salmonid feed. Research is currently underway to evaluate the use of brown algae-derived products for marine aquaculture feed of Oncorhynchus mykiss in tanks. There was no apparent adverse effect on the evaluated parameters that can be attributed to the incorporation of M. pyrifera meal in the diets fed to salmonids. Even when the control diet had numerically the best performance in zootechnical terms, the analysis of variance of all parameters evaluated showed no significant differences with regard to diets containing M. pyrifera meal. These results demonstrated that seaweed meal has important benefits for animal health and nutrition that could be applied or tested in other marine organisms of commercial importance.
Navarro N.P.,University of Magallanes |
Navarro N.P.,University of Sao Paulo |
Mansilla A.,University of Magallanes |
Mansilla A.,Institute of Ecology and Biodiversity |
Plastino E.M.,University of Sao Paulo
Journal of Applied Phycology | Year: 2010
The effects of UVB radiation on the different developmental stages of the carrageenan-producing red alga Iridaea cordata were evaluated considering: (1) carpospore and discoid germling mortality; (2) growth rates and morphology of young tetrasporophytes; and (3) growth rates and pigment content of field-collected plant fragments. Unialgal cultures were submitted to 0.17, 0.5, or 0.83W m-2 of UVB radiation for 3h per day. The general culture conditions were as follows: 12h light/12h dark cycles; irradiance of 55 μmol photon per square meter per second; temperature of 9 ± 1°C; and seawater enriched with Provasoli solution. All UVB irradiation treatments were harmful to carpospores (0.17 Wm-2 = 40.9 ± 6.9%, 0.5 Wm-2 = 59.8 ± 13.4%, 0.83 Wm-2 = 40 ± 17.4% mortality in 3days). Even though the mortality of all discoid germlings exposed to UVB radiation was unchanged when compared to the control, those germlings exposed to 0.5 and 0.83W m-2 treatments became paler and had smaller diameters than those cultivated under control treatment. Decreases in growth rates were observed in young tetrasporophytes, mainly in 0.5 and 0.83W m-2 treatments. Similar effects were only observed in fragments of adult plants cultivated at 0.83W m-2. Additionally, UVB radiation caused morphological changes in fragments of adult plants in the first week, while the young individuals only displayed this pattern during the third week. The verified morphological alterations in I. cordata could be interpreted as a defense against UVB by reducing the area exposed to radiation. However, a high level of radiation appears to produce irreparable damage, especially under long-term exposure. Our results suggest that the sensitivity to ultraviolet radiation decreases with increased algal age and that the various developmental stages have different responses when exposed to the same doses of UVB radiation. © 2009 Springer Science+Business Media B.V.
Jara I.A.,Institute of Ecology and Biodiversity |
Jara I.A.,Victoria University of Wellington |
Moreno P.I.,Institute of Ecology and Biodiversity |
Moreno P.I.,University of Chile
Quaternary Science Reviews | Year: 2014
We present a detailed record from Lago Pichilafquén to unravel the vegetation, climate and disturbance history of the lowlands of northwestern Patagonia (40°S) since 14,500calyrBP. The presence of 30 tephras throughout the record attest for the proximity of the site to active volcanic centres and allows assessment of the role of volcanic disturbance on past vegetation and fire regime shifts. We interpretalternations in dominance between North Patagonian and Valdivian rainforests driven by changes in temperature and precipitation of westerly origin at multi-millennial and millennial timescales. These trends were punctuated by centennial-scale changes, most of which were coeval with or immediately followed the deposition of tephras and/or paleofires. We identify departures of the local vegetation from the regional trend between 2400 and 7100calyrBP, which we interpret as a response of rainforest vegetation and local fire regimes to the disturbance effect of tephra deposition near Lago Pichilafquén. We also find that volcanic disturbance promoted consistent increases in Eucryphia/Caldcluvia within 30 years and paleofires between 60 and 120years following tephra deposition. Comparisons with palynological records having similar span, time resolution and age control suggest that regional climate has played a central role on the establishment, composition and maintenance of temperate rainforests. This influence is overprinted by disturbance regimes at the local and landscape level, driving divergences and heterogeneity especially at times of relatively weak climatic forcing. © 2014 Elsevier Ltd.
Sagarin R.,Marine Conservation Institute |
Pauchard A.,University of Concepción |
Pauchard A.,Institute of Ecology and Biodiversity
Frontiers in Ecology and the Environment | Year: 2010
Ecology has entered into a dynamic period, driven by both the urgency of large-scale ecological problems and startling new ecological findings that are being shared broadly beyond the scientific community. Both of these factors are well represented by observational approaches to ecology, which are re-emerging after a long period of deference to manipulative experimental approaches. These approaches examine ecological patterns and processes through data gathered in situations where nature has not been purposefully manipulated. The use of unmanipulated observational data reflects on the work of early naturalists, but is greatly enhanced by technological advances in remote sensing, microscopy, genetics, animal-borne sensors, and computing. Once dismissed as merely "exploratory", strictly observational approaches to ecology have demonstrated capability in testing hypotheses by correlating variables, comparing observed patterns to output from existing models, exploiting natural experiments, and simulating experiments within large datasets. These approaches can be used in a stand-alone fashion, but are strengthened when reconciled with experimental manipulations to isolate fine-scale ecological mechanisms. © The Ecological Society of America.
Taylor K.T.,Montana State University |
Maxwell B.D.,Montana State University |
Pauchard A.,University of Concepción |
Pauchard A.,Institute of Ecology and Biodiversity |
And 5 more authors.
Global Ecology and Biogeography | Year: 2016
Aim: To determine biotic and abiotic controls on pine invasion globally within six ecoregions that include both introduced and native ranges. Locations: Río Negro province, Argentina; Aysén and Araucanía regions, Chile; South Island (two ecoregions), New Zealand; Greater Yellowstone ecosystem, USA. Methods: We quantified tree abundance and size across invasion fronts of the widespread invasive tree species Pinus contorta at each of the nine sites, encompassing both the native and introduced range. We also determined the relative importance of propagule pressure, abiotic characteristics and biotic factors for invasion success. Finally, key plant population metrics such as individual tree growth rates and reproductive effort were compared between native and introduced ranges. Results: Pinus contorta density decreased with increasing distance from source population in all cases, but the importance and shape of this relationship differed among sites due, primarily to biotic factors. For example, areas dominated by native southern beech forest (Fuscospora cliffortioides or Nothofagus spp.) were not invaded, and this biotic resistance was not overcome by high propagule pressure. In contrast, shrublands were more highly invaded than grasslands, contradicting previous generalizations about pine invasions. Pinus contorta growth was faster, age to maturity was earlier and reproductive effort was higher in the introduced ranges compared with the native range, suggesting a demographic shift towards more rapid population growth in introduced regions. Climatic differences between the ranges may explain, at least in part, the observed pattern. Main conclusions: We demonstrate that although biological invasions are driven by propagule pressure across different ecoregions, these processes interact strongly with biotic factors. Intriguingly, our results suggest that propagule pressure may become less important than biotic interactions as invasions proceed. Multi-region studies including both the native and introduced ranges provide unparalleled opportunities for understanding how these interactions change among regions as invasions proceed. © 2016 John Wiley & Sons Ltd.