CEAZA
A holistic picture of Austronesian migrations revealed by phylogeography of Pacific paper mulberry.
Chang, C., Liu, H., Moncada, X., Seelenfreund, A., Seelenfreund, D., & Chung, K.
The peopling of Remote Oceanic islands by Austronesian speakers is a fascinating and yet contentious part of human prehistory. Linguistic, archaeological, and genetic studies have shown the complex nature of the process in which different components that helped to shape Lapita culture in Near Oceania each have their own unique history. Important evidence points to Taiwan as an Austronesian ancestral homeland with a more distant origin in South China, whereas alternative models favor South China to North Vietnam or a Southeast Asian origin. We test these propositions by studying phylogeography of paper mulberry, a common East Asian tree species introduced and clonally propagated since prehistoric times across the Pacific for making barkcloth, a practical and symbolic component of Austronesian cultures. Using the hypervariable chloroplast ndhF-rpl32 sequences of 604 samples collected from East Asia, Southeast Asia, and Oceanic islands (including 19 historical herbarium specimens from Near and Remote Oceania), 48 haplotypes are detected and haplotype cp-17 is predominant in both Near and Remote Oceania. Because cp-17 has an unambiguous Taiwanese origin and cp-17–carrying Oceanic paper mulberries are clonally propagated, our data concur with expectations of Taiwan as the Austronesian homeland, providing circumstantial support for the “out of Taiwan” hypothesis. Our data also provide insights into the dispersal of paper mulberry from South China “into North Taiwan,” the “out of South China–Indochina” expansion to New Guinea, and the geographic origins of post-European introductions of paper mulberry into Oceania.
Año: 2015
Palabras claves: Broussonetia papyrifera, commensal approach, DNA of herbarium specimens, out of Taiwan hypothesis, Voyaging Corridor Triple I .
Referencia APA: Chang, C., Liu, H., Moncada, X., Seelenfreund, A., Seelenfreund, D., & Chung, K. (2015). A holistic picture of Austronesian migrations revealed by phylogeography of Pacific paper mulberry. Proceedings Of The National Academy Of Sciences, 112(44), 13537-13542.
Fungal endophytes associated with roots of nurse cushion species have positive effects on native and invasive beneficiary plants in an alpine ecosystem.
Molina-Montenegro, M., Oses, R., Torres-Díaz, C., Atala, C., Núñez, M., & Armas, C.
Facilitation has been proposed to be a fundamental mechanism for plant coexistence, being particularly important in highly stressful environments such as alpine environments. In this type of environment, species called “cushion plants” can ameliorate the stressful conditions, acting as nurses for other plants. Of the several mechanisms proposed in the positive-interactions framework, plant–microorganism interaction may be one of the most common, but least documented. Here we show that the presence of endophytes isolated from the roots of cushion plants Laretia acaulis can play a fundamental role in the establishment, performance and survival of both native and exotic plant seedlings that are known to be facilitated by the cushion species.
To test this, we measured survival and growth of two native and one invasive species at 3200 m in the Andes of Central Chile. Plants were grown inside artificial cushions filled with native soil, with or without sterilization, and with or without fungal endophytic inoculation to evaluate the role of fungal endophytes on survival and growth. In addition, we conducted a second experiment in a greenhouse with the invasive species to evaluate the effect of fungal endophytic infection/association on plant ecophysiological performance, dry biomass and seed output.
Overall, our results showed a strong positive effect of fungal endophytes on the survival and growth of both native and invasive species. Moreover, maximum quantum efficiency (Fv/Fm), biomass accumulation and seed production were enhanced in the invasive species when soils were inoculated with endophytes. Thus, facilitation by root endophytic fungi on native and invasive alpine plants could determine survival and establishment in this harsh environment.
Several studies have shown that direct facilitation by cushion plants in alpine environments improves the performance and fitness of both native and exotic plants. Our results suggest that there are indirect effects, mediated by microorganism associations that may also help to explain the successful establishment of native and invasive species in these environments. If indirect plant–plant facilitation through root fungal endophytes proves to be a widespread phenomenon in alpine ecosystems, it could be a key component in the structuring of plant communities in those stressful environments.
Año: 2015
Palabras claves: Cushion plants; Endophytic fungi; Facilitation; Invasive species; Positive interactions; Taraxacum officinale.
Referencia APA: Molina-Montenegro, M., Oses, R., Torres-Díaz, C., Atala, C., Núñez, M., & Armas, C. (2015). Fungal endophytes associated with roots of nurse cushion species have positive effects on native and invasive beneficiary plants in an alpine ecosystem. Perspectives In Plant Ecology, Evolution And Systematics, 17(3), 218-226.
Ecophysiological responses to drought followed by re-watering of two native Chilean swamp forest plants: Myrceugenia exsucca (DC.) O. Berg and Luma chequen (Molina) A. Gray
Bascuñán-Godoy, L., Alcaíno, C., Carvajal, D., Sanhueza, C., Montecinos, S., & Maldonado, A.
Myrceugenia exsucca (DC.) O. Berg and Luma chequen (Molina) A. Gray are two predominant species of Myrtaceae from the swamp forest which are strongly threatened by destruction of their habitat. Conservation programs include the creation of new protected areas which often have different environmental conditions respect their natural habitat. The drought tolerance and the capability to restore their physiological performance after stress relief are characteristic of great importance for the successful conservation programs on these kinds of plants. Understanding how these plants respond to episodic drought and watering pulse was the principal aim of this work. In this sense, water relations, soluble sugars, pigments and photosystem II (PSII) performance were studied. In general the water relationships were less affected by drought in L. chequen than in M. exsucca which was consistent with a higher maintenance of photochemical quenching (qP) in the first one. In addition, L. chequen exhibited complete recovery of water potential and maximum PSII efficiency and increasing the proportion of photochemical processes and soluble sugars related with a higher photosynthetic recovery. Contrastingly, M. exsucca was unable to recover its water potential and the proportion of open reaction centers of PSII under re-watering indicating a lower capacity of recovery. These results shown different capabilities to cope and reestablish physiological performance after water scarcity episode between these two native chilean swamp forest plants. We hope that these results will be important for conservation and re-vegetation managements programs.
Año: 2015
Palabras claves: Myrtaceae, photosynthetic performance, water deficit, re-watering.
Referencia APA: Bascuñán-Godoy, L., Alcaíno, C., Carvajal, D., Sanhueza, C., Montecinos, S., & Maldonado, A. (2015). Ecophysiological responses to drought followed by re-watering of two native Chilean swamp forest plants: Myrceugenia exsucca (DC.) O. Berg and Luma chequen (Molina) A. Gray. Gayana Bot., 72(2), 203-212.
Castaways can’t be choosers — Homogenization of rafting assemblages on floating seaweeds.
Gutow, L., Beermann, J., Buschbaum, C., M. Rivadeneira, M., & Thiel, M.
After detachment from benthic habitats, the epibiont assemblages on floating seaweeds undergo substantial changes, but little is known regarding whether succession varies among different seaweed species. Given that floating algae may represent a limiting habitat in many regions, rafting organisms may be unselective and colonize any available seaweed patch at the sea surface. This process may homogenize rafting assemblages on different seaweed species, which our study examined by comparing the assemblages on benthic and floating individuals of the fucoid seaweeds Fucus vesiculosus and Sargassum muticum in the northern Wadden Sea (North Sea). Species richness was about twice as high on S. muticum as on F. vesiculosus, both on benthic and floating individuals. In both seaweed species benthic samples were more diverse than floating samples. However, the species composition differed significantly only between benthic thalli, but not between floating thalli of the two seaweed species. Separate analyses of sessile and mobile epibionts showed that the homogenization of rafting assemblages was mainly caused by mobile species. Among these, grazing isopods from the genus Idotea reached extraordinarily high densities on the floating samples from the northern Wadden Sea, suggesting that the availability of seaweed rafts was indeed limiting. Enhanced break-up of algal rafts associated with intense feeding by abundant herbivores might force rafters to recolonize benthic habitats. These colonization processes may enhance successful dispersal of rafting organisms and thereby contribute to population connectivity between sink populations in the Wadden Sea and source populations from up-current regions.
Año: 2015
Palabras claves: Epibiota; Wadden Sea; Population Connectivity; Habitat Destruction; Migration; Dispersal.
Referencia APA: Gutow, L., Beermann, J., Buschbaum, C., M. Rivadeneira, M., & Thiel, M. (2015). Castaways can't be choosers — Homogenization of rafting assemblages on floating seaweeds. Journal Of Sea Research, 95, 161-171.
Facilitative Effect of a Generalist Herbivore on the Recovery of a Perennial Alga: Consequences forPersistence at the Edge of Their Geographic Range.
Aguilera MA, Valdivia N, Broitman BR.
Understanding the impacts of consumers on the abundance, growth rate, recovery and persistence of their resources across their distributional range can shed light on the role of trophic interactions in determining species range shifts. Here, we examined if consumptive effects of the intertidal grazer Scurria viridula positively influences the abundance and recovery from disturbances of the alga Mazzaella laminarioides at the edge of its geographic distributions in northern-central Chilean rocky shores. Through field experiments conducted at a site in the region where M. laminarioides overlaps with the polar range edge of S. viridula, we estimated the effects of grazing on different life stages of M. laminarioides. We also used long-term abundance surveys conducted across ~700 km of the shore to evaluate co-occurrence patterns of the study species across their range overlap. We found that S. viridula had positive net effects on M. laminarioides by increasing its cover and re-growth from perennial basal crusts. Probability of occurrence of M. laminarioides increased significantly with increasing density of S. viridula across the range overlap. The negative effect of S. viridula on the percentage cover of opportunistic green algae—shown to compete for space with corticated algae—suggests that competitive release may be part of the mechanism driving the positive effect of the limpet on the abundance and recovery from disturbance of M. laminarioides. We suggest that grazer populations contribute to enhance the abundance of M. laminarioides, facilitating its recolonization and persistence at its distributional range edge. Our study highlights that indirect facilitation can determine the recovery and persistence of a resource at the limit of its distribution, and may well contribute to the ecological mechanisms governing species distributions and range shifts.
Año: 2015
Palabras claves: Algae, Fronds, Grazing, Herbivory, Plant-herbivore interactions, Species interactions, Geographic distribution,Trophic interactions.
Referencia APA: Valdivia N, Broitman BR. (2015). Facilitative Effect of a Generalist Herbivore on the Recovery of a Perennial Alga: Consequences for Persistence at the Edge of Their Geographic Range. PLoS ONE 10(12): e0146069.
A recolonization record of the invasive Poa annua in Paradise Bay, Antarctic Peninsula: modeling of the potential spreading risk.
Molina-Montenegro, M., Pertierra, L., Razeto-Barry, P., Díaz, J., Finot, V., & Torres-Díaz, C.
Antarctica is one of the most extreme environments for vascular plants occurrence worldwide, and only two native vascular plants have colonized this continent: Deschampsia antarctica and Colobanthus quitensis. Nevertheless, in recent years, several alien plant species has been found in Antarctica with negative effects on the native flora. In this study, we show a recolonization record of the most widespread plant invader in Antarctica (Poa annua) and the risk of a potential spreading in a highly visited site on the Antarctic Peninsula. Overall, two new P. annua individuals were recorded, where four specimens were previously reported and removed in 2010, suggesting that either a propagule load is continuous, or that a seed bank prevailed in the site. On the other hand, the spreading modeling suggests that the probability to colonize and spreading of P. annua increases notoriously with the possibility of dispersion of propagules, with consequent risk of displacement for the native flora. Biological invasions are a major threat to the integrity of native biodiversity in all biomes, and they have the potential to change irreversibly Antarctica’s fragile ecosystems.
Año: 2015
Palabras claves: Antarctica, Biodiversity, Invasions, Poa annua.
Referencia APA: Molina-Montenegro, M., Pertierra, L., Razeto-Barry, P., Díaz, J., Finot, V., & Torres-Díaz, C. (2015). A recolonization record of the invasive Poa annua in Paradise Bay, Antarctic Peninsula: modeling of the potential spreading risk. Polar Biol, 38(7), 1091-1096.
Dust fluxes and iron fertilization in Holocene and Last Glacial Maximum climates.
Lambert, F., Tagliabue, A., Shaffer, G., Lamy, F., Winckler, G., & Farias, L. et al.
Mineral dust aerosols play a major role in present and past climates. To date, we rely on climate models for estimates of dust fluxes to calculate the impact of airborne micronutrients on biogeochemical cycles. Here we provide a new global dust flux data set for Holocene and Last Glacial Maximum (LGM) conditions based on observational data. A comparison with dust flux simulations highlights regional differences between observations and models. By forcing a biogeochemical model with our new data set and using this model's results to guide a millennial-scale Earth System Model simulation, we calculate the impact of enhanced glacial oceanic iron deposition on the LGM-Holocene carbon cycle. On centennial timescales, the higher LGM dust deposition results in a weak reduction of <10 ppm in atmospheric CO2 due to enhanced efficiency of the biological pump. This is followed by a further ~10 ppm reduction over millennial timescales due to greater carbon burial and carbonate compensation.
Año: 2015
Palabras claves: Paleoclimate; dust; iron fertilization; atmospheric CO2; carbon cycle; LGM.
Referencia APA: Lambert, F., Tagliabue, A., Shaffer, G., Lamy, F., Winckler, G., & Farias, L. et al. (2015). Dust fluxes and iron fertilization in Holocene and Last Glacial Maximum climates. Geophys. Res. Lett., 42(14), 6014-6023.
Biogeographic structure of the northeastern Pacific rocky intertidal: the role of upwelling and dispersal to drive patterns.
Fenberg, P., Menge, B., Raimondi, P., & Rivadeneira, M.
Identifying the environmental conditions that drive biogeographic structure remains a major challenge of biogeography, evolutionary ecology and increasingly, conservation biology. Here, we use multivariate classification trees to assess the biogeographic structure of northeast Pacific (∼ 26–58°N) rocky intertidal species (406 species of algae and invertebrates) from 102 field sites. Random forest analyses are used to assess the importance of 29 environmental variables, encompassing a broad range of potential drivers, to predict biogeographic structure. Analyses are repeated for species with different larval dispersal capabilities and by broad taxonomic categories (invertebrates and algae). Results show that overall biogeographic structure is in general agreement with classic classification schemes, but patterns are variable among species with different larval dispersal capabilities. Random forest models show a very high fit (pseudo r2 > 0.94) and indicate that biogeographic structure can be predicted by a relatively modest subset of variables. Upwelling related variables are the best overall predictors of biogeographic structure (nutrient concentrations, sea-surface temperature, upwelling/downwelling seasonal switch index), but the relative importance of predictors is geographically variable and top predictors are dependent on the type of larval dispersal. Upwelling related variables are more important to predict biogeographic structure for invertebrates with lower-medium dispersal capabilities and algae, whereas species with high larval dispersal (planktotrophic) are better predicted by a different subset of variables (i.e. salinity, precipitation seasonality). Our results lend support to the influence of coastal upwelling in structuring biogeographic patterns and highlight the potential for climate change-induced alterations of upwelling regimes to profoundly affect biodiversity at biogeographic scales.
Año: 2015
Palabras claves:
Referencia APA: Fenberg, P., Menge, B., Raimondi, P., & Rivadeneira, M. (2015). Biogeographic structure of the northeastern Pacific rocky intertidal: the role of upwelling and dispersal to drive patterns. Ecography, 38(1), 83-95.
Poa annua L. in the maritime Antarctic: an overview.
Chwedorzewska, K., Giełwanowska, I., Olech, M., Molina-Montenegro, M., Wódkiewicz, M., & Galera, H.
Poa annua is the only flowering plant species that has established a breeding population in the maritime Antarctic, through repeated anthropogenic introduction. The first appearance of this species in the Antarctic was observed in 1953. Annual bluegrass inhabits mainly anthropogenic sites, but recently has entered tundra communities. The functioning of P. annua in the Antarctic could not have been possible without adaptations that enable the plants to persist in the specific climatic conditions typical for this zone. Poa annua is highly adaptable to environmental stress and unstable habitats: huge phenotypic and genotypic variability, small size, plastic life cycle (life-history types ranging from annual to perennial forms). The spreading of P. annua in the Antarctic Peninsula region is a classic example of the expansion process following anthropogenic introduction of an invasive species, and illustrates the dangers to Antarctic terrestrial ecosystems that are associated with increasing human traffic.
Año: 2015
Palabras claves:
Referencia APA: Chwedorzewska, K., Giełwanowska, I., Olech, M., Molina-Montenegro, M., Wódkiewicz, M., & Galera, H. (2015). Poa annua L. in the maritime Antarctic: an overview. Polar Record, 51(06), 637-643.
Biological invasions in terrestrial Antarctica: what is the current status and can we respond?.
Hughes, K., Pertierra, L., Molina-Montenegro, M., & Convey, P.
Until recently the Antarctic continent and Peninsula have been little impacted by non-native species, compared to other regions of the Earth. However, reports of species introductions are increasing as awareness of biological invasions as a major conservation threat, within the context of increased human activities and climate change scenarios, has grown within the Antarctic community. Given the recent increase in documented reports, here we provide an up-to-date inventory of known terrestrial non-native species introductions, including those subsequently removed since the 1990s, within the Antarctic Treaty area. This builds on earlier syntheses of records published in the mid-2000s, which focused largely on the sub-Antarctic islands, given the dearth of literature available at that time from the continental and maritime Antarctic regions. Reports of non-native species established in the natural environment (i.e. non-synanthropic) are mainly located within the Antarctic Peninsula region and Scotia Arc, with Deception Island, South Shetland Islands, the most impacted area. Non-native plants have generally been removed from sites of introduction, but no established invertebrates have yet been subject to any eradication attempt, despite a recent increase in reports. Legislation within the Protocol on Environmental Protection to the Antarctic Treaty has not kept pace with environmental best practice, potentially presenting difficulties for the practical aspects of non-native species control and eradication. The success of any eradication attempt may be affected by management practices and the biology of the target species under polar conditions. Practical management action is only likely to succeed with greater co-operation and improved communication and engagement by nations and industries operating in the region.
Año: 2015
Palabras claves: Antarctic Treaty area, Environmental Protocol, Alien species, Biosecurity, Invasion, Eradication.
Referencia APA: Hughes, K., Pertierra, L., Molina-Montenegro, M., & Convey, P. (2015). Biological invasions in terrestrial Antarctica: what is the current status and can we respond?. Biodiversity And Conservation, 24(5), 1031-1055.
Assimilation of GRACE Terrestrial Water Storage Observations into a Land Surface Model for the Assessment of Regional Flood Potential.
Reager, J., Thomas, A., Sproles, E., Rodell, M., Beaudoing, H., Li, B., & Famiglietti, J.
We evaluate performance of the Catchment Land Surface Model (CLSM) under flood conditions after the assimilation of observations of the terrestrial water storage anomaly (TWSA) from NASA’s Gravity Recovery and Climate Experiment (GRACE). Assimilation offers three key benefits for the viability of GRACE observations to operational applications: (1) near-real time analysis; (2) a downscaling of GRACE’s coarse spatial resolution; and (3) state disaggregation of the vertically-integrated TWSA. We select the 2011 flood event in the Missouri river basin as a case study, and find that assimilation generally made the model wetter in the months preceding flood. We compare model outputs with observations from 14 USGS groundwater wells to assess improvements after assimilation. Finally, we examine disaggregated water storage information to improve the mechanistic understanding of event generation. Validation establishes that assimilation improved the model skill substantially, increasing regional groundwater anomaly correlation from 0.58 to 0.86. For the 2011 flood event in the Missouri river basin, results show that groundwater and snow water equivalent were contributors to pre-event flood potential, providing spatially-distributed early warning information.
Año: 2015
Palabras claves: GRACE; gravity; flood; assimilation.
Referencia APA: Reager, J., Thomas, A., Sproles, E., Rodell, M., Beaudoing, H., Li, B., & Famiglietti, J. (2015). Assimilation of GRACE Terrestrial Water Storage Observations into a Land Surface Model for the Assessment of Regional Flood Potential. Remote Sensing, 7(11), 14663-14679.
Late Quaternary climate change, relict populations and present-day refugia in the northern Atacama Desert: a case study from Quebrada La Higuera (18° S).
Mujica, M., Latorre, C., Maldonado, A., González-Silvestre, L., Pinto, R., de Pol-Holz, R., & Santoro, C.
In deserts, past climate change (and particularly past rainfall variability) plays a large role in explaining current plant species distributions. We ask which species were most and which were least affected by changes in rainfall during the late Quaternary in northernmost Chile.
Año: 2015
Palabras claves: Altiplano; Atacama Desert; central Andes; late Quaternary; pluvial events; refugia; relict populations; rodent middens.
Referencia APA: Mujica, M., Latorre, C., Maldonado, A., González-Silvestre, L., Pinto, R., de Pol-Holz, R., & Santoro, C. (2015). Late Quaternary climate change, relict populations and present-day refugia in the northern Atacama Desert: a case study from Quebrada La Higuera (18° S). Journal Of Biogeography, 42(1), 76-88.