CEAZA
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.
Ancient and modern introduction of Broussonetia papyrifera ([L.] Vent.; Moraceae) into the Pacific: genetic, geographical and historical evidence.
González-Lorca, J., Rivera-Hutinel, A., Moncada, X., Lobos, S., Seelenfreund, D., & Seelenfreund, A.
Broussonetia papyrifera (L.) Vent. (Moraceae), or paper mulberry, is a species of cultural importance in South East Asia, East Asia and the Pacific. Originally from mainland South East Asia or East Asia, this plant was introduced into the Pacific range by prehistoric Austronesian voyagers. We used non-coding internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA and inter-simple sequence repeat (ISSR) on 79 samples of B. papyrifera from different islands of Remote Oceania, and South East Asia and East Asia. Our results show an absence of genetic diversity in the introduced range of Remote Oceania, with the sole exception of Hawaii. By contrast, Asian samples show genetic diversity. The data obtained suggest a prehistoric human-mediated introduction of this species from East Asia to Remote Oceania and a second, possibly historic, human-mediated introduction to Hawaii.
Año: 2015
Palabras claves: Asia, human-mediated dispersal, ISSR, ITS, paper mulberry, Polynesia.
Referencia APA: González-Lorca, J., Rivera-Hutinel, A., Moncada, X., Lobos, S., Seelenfreund, D., & Seelenfreund, A. (2015). Ancient and modern introduction of Broussonetia papyrifera ([L.] Vent.; Moraceae) into the Pacific: genetic, geographical and historical evidence. New Zealand Journal Of Botany, 53(2), 75-89
Sampling of riverine litter with citizen scientists — findings and recommendations.
Rech, S., Macaya-Caquilpán, V., Pantoja, J., Rivadeneira, M., Campodónico, C., & Thiel, M.
The quantity and composition of litter at riversides and in the surface waters, as well as the occurrence of illegal dumping sites, were studied along four rivers in Chile. Data generated by volunteers were compared to the results from a professional survey, using an identical protocol. Litter was found in considerable quantities at the riversides and in the surface waters at all the sites investigated. A generalized linear mixed model analysis showed that the recorded litter densities did not differ between volunteers and professionals, even after controlling for river, site, or distance between sampling locations, demonstrating that the volunteers successfully applied the sampling protocol. Differences occurred with respect to litter composition, which is most likely due to difficulties in the classification of litter items and particles and to the underestimation of litter present in surface water samples. Even though this study was only conducted at a small number of rivers and sites, a comparatively consistent pattern of direct and intentional litter deposition at riversides was recorded, highlighting that river basins require more protection. The results also show that the citizen science approach can be a suitable means for more extensive litter surveys at riversides and in other natural environments.
Año: 2015
Palabras claves: Citizen science, Data validation, Litter abundance, Litter sources, Riverine litter, Floating microplastics.
Referencia APA: Rech, S., Macaya-Caquilpán, V., Pantoja, J., Rivadeneira, M., Campodónico, C., & Thiel, M. (2015). Sampling of riverine litter with citizen scientists — findings and recommendations. Environmental Monitoring And Assessment, 187(6).