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Context The New Zealand mudsnail, Potamopyrgus antipodarum, has invaded numerous countries around the world, including Chile. Aim We aimed to determine variation in shell morphology and fecundity in 12 populations scattered in six hydrological basins in this country. Methods Populations were compared using shell morphometry, principal-component analysis (PCA), and brood size. Independent linear mixed models (LMM) were applied to study spatially correlated data. Results The morphometric analysis showed significant differences in shell variables, whereas the PCA showed a high degree of overlap of specimens as well as separation of populations in the morphometric space. Brood size differed significantly among populations, ranging from 0 to 63 offspring. Altitude and shell length had an effect on brood size, whereas shell length showed variation among basins. Latitude did not have a direct effect on any of the two variables. Conclusions Potamopyrgus antipodarum exhibits great morphological and life-history trait variation, which could be favouring its rapid expansion in Chile. The lack of genetic variation of this species, previously reported in the country, suggests that differences found in our study are likely to be due to environmental variation. Implications Further studies should be addressed to assess the origin of the variance.

We assessed the effect that electromagnetic field (EMF) exerts on honeybees’ pollination efficiency using field and laboratory experiments. First, we measured levels of gene and protein expression in metabolic pathways involved in stress and behavioral responses elicited by EMF. Second, we assessed the effect of EMF on honeybee behavior and seed production by the honeybee-pollinated California poppy and, lastly, by measuring the consequences of pollination failure on plants’ community richness and abundance. EMF exposure exerted strong physiological stress on honeybees as shown by the enhanced expression of heat-shock proteins and genes involved in antioxidant activity and affected the expression levels of behavior-related genes. Moreover, California poppy individuals growing near EMF received fewer honeybee visits and produced fewer seeds than plants growing far from EMF. Last, we found a hump-shaped relationship between EMF and plant species richness and plant abundance. Our study provides conclusive evidence of detrimental impacts of EMF on honeybee’s pollination behavior, leading to negative effects on plant community.

Solar activity has a significant influence on Earth's climate and may drive many biological processes. Here, we measured growth in 11 tree species distributed along an ≈600-km latitudinal gradient in South-Central Chile, recording the width of their growth-rings among periods of maximum (highest number of sunspots) and minimum (lowest number of sunspots) solar activity. In one of these species, Quillaja saponaria, we experimentally assessed three ecophysiological traits (CO

For plants, reactive oxygen species (ROS) and ultraviolet B radiation (UV-B) stand out as important genotoxic agents. Hence, the genetic damage among the Antarctic vascular flora, whose individuals frequently experience these abiotic stresses, might be recurrent among their populations. To respond this, the genetic damage associated with these stress factors was evaluated in Colobanthus quitensis and Deschampsia antarctica for the first time in the field and compared with those showed by plants grown at laboratory under less stressful conditions. Fifteen individuals per species from Admiralty Bay populations at King George Island (Maritime Antarctica) were used to semi-quantitatively estimate the genetic damage at the whole genome level by the single-cell gel electrophoresis (SCGE) assay, revealing by means of specific enzymatic treatments the damage generated by oxidative stress (oxidized purines and pyrimidines) and UV-B radiation (pyrimidine dimmers). Compared with laboratory control individuals, the basal genetic damage observed in both species was significantly higher under field conditions. However, while for C. quitensis, oxidative stress (Ox) was more relevant than UV-B radiation (field relative revealed damage: Ox = 29% vs. UV-B = 25%), in D. antarctica, it was UV-B radiation the most relevant genotoxic factor (Ox = 10% vs. UV-B = 33%). This first approach to the genetic damage of the Antarctic vascular flora suggests that the conditions experienced on their natural ecosystems would constitute a genotoxic environment for these species, yet with differential impact between them.

Fungal endophyte associations have been suggested as a possible strategy of Antarctic vascular plants for surviving the extreme environmental conditions of Antarctica. However, the mechanisms by which this occurs are still poorly understood. The role of root fungal endophytes in nitrogen mineralization and nutrient uptake, as well as their impact on the performance of Antarctic plants, were studied. We tested root endophytes, isolated from Colobanthus quitensis and Deschampsia antarctica, for lignocellulolytic enzyme production, nitrogen mineralization, and growth enhancement of their host plants. Penicillium chrysogenum and Penicillium brevicompactum were identified using a molecular approach as the main root endophytes inhabiting C. quitensis and D. antarctica, respectively. Both root endophytes were characterized as psychrophilic fungi displaying amylase, esterase, protease, cellulase, hemicellulase, phosphatase and urease enzymatic activities, mainly at 4 °C. Moreover, the rates and percentages of nitrogen mineralization, as well as the final total biomass, were significantly higher in symbiotic C. quitensis and D. antarctica individuals. Our findings suggest that root endophytes exert a pivotal ecological role based not only to breakdown different nutrient sources but also on accelerating nitrogen mineralization, improving nutrient acquisition, and therefore promoting plant growth in Antarctic terrestrial ecosystems.

Invasive plants may displace native species. This is the case for Poa annua, the only non-native plant species successfully established in Maritime Antarctica. Nonetheless, it is uncertain which factors drive the competitive success of P. annua in the harsh environmental conditions of the region. The ability of this plant species to establish novel mutualistic interactions with resident soil fungi may be crucial for its invasiveness. Such ability may be linked to the vertical transmission of fungal endophytes via seeds. We undertook a study to assess the role of seed fungal endophytes as promoters of the establishment and invasion of Poa annua in Maritime Antarctica. We explored the composition and diversity of fungal communities associated with different P. annua tissues (seeds, leaves and roots) and the soil. We also measured parameters including germination rate, above-ground biomass, reproductive structures, and the survival of invasive P. annua as well as of the native Colobanthus quitensis and Deschampsia antarctica grown from seeds with and without endophytes. Furthermore, we conducted inter- and intraspecific competition experiments among native and invasive plants, where chemically mediated plant-to-plant interference (allelopathy) and plant growth rate were measured to calculate a relative competition index. We found that fungal endophyte taxa associated with P. annua tissues were very different from those in the soil. Fungal endophytes in P. annua differed among seed, root and shoot tissues, which suggests low transmission among different organs. The removal of endophytes from P. annua seeds was associated with reduced seed germination, plant growth and survivorship, while the competitive ability of P. annua (assessed by accumulated biomass) relative to native species, as well as levels of allelochemicals in soils, were higher in the presence of seed fungal endophytes. Our results suggest that fungal endophytes, maternally inherited through seeds, improve host fitness and may contribute to the invasive success of P. annua in Antarctica.

Significant risks to human health have been associated with chronic exposure to low doses of pesticides, a situation which may be frequent among agricultural workers. In this context, and regarding the agricultural-based economy of central Chile, we aimed to explore the genotoxic damage in agricultural workers and reproductive risk among women in rural and urban areas of Curicó, a traditional agricultural district in Chile. Hence, we sampled a group of rural agricultural workers associated with pesticide management (n = 30) and an urban unexposed group (n = 30). Our results showed that the agricultural workers had higher micronuclei frequencies (MN: β = 13.27; 95% CI low = 11.08, CI high = 15.47) and women had a 40-fold higher risk of reproductive problems (OR = 40.32; 95% CI low = 2.60, CI high = 624.31) than the unexposed group. The factor analysis of mixed data (FAMD) showed that neither the sex nor smoking habits appear to define the ordination of the data. Nevertheless, the exposure level did segregate them in the multidimensional space (explained variance: 35.38% dim-1; 18.63% dim-2). This pilot study highlights the higher risks of biological conditions negatively associated with the health of agricultural workers.

Biological soil crusts (BSC) are considered as pivotal ecological elements among different ecosystems of the world. The effects of these BSC at the micro-site scale have been related to the development of diverse plant species that, otherwise, might be strongly limited by the harsh abiotic conditions found in environments with low water availability. Here, we describe for the first time the bacterial composition of BSCs found in the proximities of Admiralty Bay (Maritime Antarctica) through 16S metabarcoding. In addition, we evaluated their effect on soils (nutrient levels, enzymatic activity, and water retention), and on the fitness and performance of Colobanthus quitensis, one of the two native Antarctic vascular plants. This was achieved by comparing the photochemical performance, foliar nutrient, biomass, and reproductive investment between C. quitensis plants growing with or without the influence of BSC. Our results revealed a high diversity of prokaryotes present in these soil communities, although we found differences in terms of their abundances. We also found that the presence of BSCs is linked to a significant increase in soils’ water retention, nutrient levels, and enzymatic activity when comparing with control soils (without BSCs). In the case of C. quitensis, we found that measured ecophysiological performance parameters were significantly higher on plants growing in association with BSCs. Taken together, our results suggest that BSCs in Antarctic soils are playing a key role in various biochemical processes involved in soil development, while also having a positive effect on the accompanying vascular flora. Therefore, BSCs would be effectively acting as ecosystem engineers for the terrestrial Antarctic ecosystem.

Beneficial plant-associated microorganisms, such as fungal endophytes, are key partners that normally improve plant survival under different environmental stresses. It has been shown that microorganisms from extreme environments, like those associated with the roots of Antarctica plants, can be good partners to increase the performance of crop plants and to restore endangered native plants. Nothofagus alessandrii and N. glauca, are among the most endangered species of Chile, restricted to a narrow and/or limited distributional range associated mainly to the Maulino forest in Chile. Here we evaluated the effect of the inoculation with a fungal consortium of root endophytes isolated from the Antarctic host plant Colobanthus quitensis on the ecophysiological performance [photosynthesis, water use efficiency (WUE), and growth] of both endangered tree species. We also, tested how Antarctic root-fungal endophytes could affect the potential distribution of N. alessandrii through niche modeling. Additionally, we conducted a transplant experiment recording plant survival on 2 years in order to validate the model. Lastly, to evaluate if inoculation with Antarctic endophytes has negative impacts on native soil microorganisms, we compared the biodiversity of fungi and bacterial in the rhizospheric soil of transplanted individuals of N. alessandrii inoculated and non-inoculated with fungal endophytes. We found that inoculation with root-endophytes produced significant increases in N. alessandrii and N. glauca photosynthetic rates, water use efficiencies and cumulative growth. In N. alessandrii, seedling survival was significantly greater on inoculated plants compared with non-inoculated individuals. For this species, a spatial distribution modeling revealed that, inoculation with root-fungal endophytes could potentially increase the current distributional range by almost threefold. Inoculation with root-fungal endophytes, did not reduce native rhizospheric microbiome diversity. Our results suggest that the studied consortium of Antarctic root-fungal endophytes improve the ecophysiological performance as well as the survival of inoculated trees and can be used as a biotechnological tool for the restoration of endangered tree species.

Aim: Antarctica's remote and extreme terrestrial environments are inhabited by only two species of native vascular plants. We assessed genetic connectivity amongst Antarctic and South American populations of one of these species, Colobanthus quitensis, to determine its origin and age in Antarctica. Location: Maritime Antarctic, sub-Antarctic islands, South America. Taxon: Antarctic pearlwort Colobanthus quitensis (Caryophyllaceae). Methods: Four chloroplast markers and one nuclear marker were sequenced from 270 samples from a latitudinal transect spanning 21–68° S. Phylogeographic, population genetic and molecular dating analyses were used to assess the demographic history of C. quitensis and the age of the species in Antarctica. Results: Maritime Antarctic populations consisted of two different haplotype clusters, occupying the northern and southern Maritime Antarctic. Molecular dating analyses suggested C. quitensis to be a young (

In this review, we examine the functional roles of microbial symbionts in plant tolerance to cold and freezing stresses. The impacts of symbionts on antioxidant activity, hormonal signaling and host osmotic balance are described, including the effects of the bacterial endosymbionts Burkholderia, Pseudomonas and Azospirillum on photosynthesis and the accumulation of carbohydrates such as trehalose and raffinose that improve cell osmotic regulation and plasma membrane integrity. The influence of root fungal endophytes and arbuscular mycorrhizal fungi on plant physiology at low temperatures, for example their effects on nutrient acquisition and the accumulation of indole-3-acetic acid and antioxidants in tissues, are also reviewed. Meta-analyses are presented showing that aspects of plant performance (shoot biomass, relative water content, sugar and proline concentrations and Fv /Fm ) are enhanced in symbiotic plants at low (-1 to 15 °C), but not at high (20-26 °C), temperatures. We discuss the implications of microbial symbionts for plant performance at low and sub-zero temperatures in the natural environment and propose future directions for research into the effects of symbionts on the cold and freezing tolerances of plants, concluding that further studies should routinely incorporate symbiotic microbes in their experimental designs.

In the southern Andes mountains (27-39◦S) Azorella madreporica and Laretia acaulis, two Apiaceae cushion plant species commonly known as yaretas, conform a well-established altitudinal vegetation belt along the lower Andean zone. These species have been considered as fundamental components of several ecological dynamics within their communities; however, high mountain ecosystems are increasingly threatened worldwide by natural and anthropogenic pressures and the southern Andes are not the exception. Recognizing that genetic information is crucial for the success of any conservation or restoration initiative inwild populations, we developed and cross-amplified 28 specifically designed microsatellite markers (14 in A. madreporica and 14 in L. acaulis), and also tested the cross amplification of 25 markers from the related species Azorella selago. In a region which is particularly vulnerable to global change trends, this new polymorphic microsatellite loci will be useful in the study of the genetic diversity of these high-mountain cushion plants, which are pivotal in the structuring of their native ecosystems.

Chloraea is a diverse orchid genus with many endemic Chilean species. Many of those species have conservation problems, and the status of their populations is unknown. Chloraea disoides Lindl. is a Critically Endangered species endemic to Chile with a narrow distribution, and many of its registered populations are located in highly disturbed sites. The restricted distribution, the increasing anthropic disturbances, and global change could lead to the rapid extinction of C. disoides. Our work aims to characterize actual populations (in Valparaiso and one in Angol), design an index to determine the conservation status of these populations, and study the potential impact that the reduction in precipitations could have on the distribution of this species, as predicted by climate change models. Using herbarium data and field collections, we registered the populations of C. disoides present in Chile and modeled the potential distribution of the species using computer models based on climatic variables. We also characterized two populations at the two ends of its distribution (Valparaiso in the north and Angol in the south). The predictive model resulted in a very narrow potential distribution for the species, superposing known populations. Some of the historical populations are now urbanized areas. Valparaiso (northern) populations presented a very low density of C. disoides individuals. Both studied populations were highly disturbed with evidence of cattle damage and human influence. Chloraea disoides is seriously threatened by anthropogenic disturbances, especially since its distribution is very narrow and the species is not well represented in protected areas. Conservation initiatives should include protection of some of the natural populations and ex situ reproduction/propagation using fungal isolates.

Antarctica is one of the less prone environments for plant invasions, nevertheless a growing number of non-native species have been registered in the last decades with negative effects on native flora. Here we assessed adaptive phenotypic plasticity in three photoprotective traits (non-photochemical quenching, total soluble sugars, and de-epoxidation state of xanthophylls cycle), and fitness-related traits (maximum quantum yield, photosynthetic rate and total biomass) in the invasive species Poa annua and Deschampsia antarctica under current conditions of water availability and those projected by climate change models. In addition, two manipulative experiments in controlled and field conditions were conducted to evaluate the competitive ability and survival of both species under current and climate change conditions. Moreover, we performed an experiment with different water availabilities to assess cell damage as a potential mechanism involved in the competitive ability deployed in both species. Finally, was assessed the plasticity and biomass of both species subject to factorial abiotic scenarios (water × temperature, and water × nutrients) ranging from current to climate change condition. Overall, results showed that P. annua had greater phenotypic plasticity in photoprotective strategies, higher performance, and greater competitive ability and survival than D. antarctica under current and climate change conditions. Also, cell damage, assessed by lipid peroxidation, was significantly greater in D. antarctica when grown in presence of P. annua compared when grown alone. Finally, P. annua showed a greater plasticity and biomass than D. antarctica under the factorial abiotic scenarios, being more evident under a climate change scenario (i.e., higher soil moisture). Our study suggests that the high adaptive plasticity and competitive ability deployed by P. annua under current and climate change conditions allows it to cope with harsh abiotic conditions and could help explain its successful invasion in the Antarctica.

Salinization of soils is one of the main sources of soil degradation worldwide, particularly in arid and semiarid ecosystems. High salinity results in osmotic stress and it can negatively impact plant grow and survival. Some plant species, however, can tolerate salinity by accumulating osmolytes like proline and maintaining low Na+ concentrations inside the cells. Another mechanism of saline stress tolerance is the association with symbiotic microorganism, an alternative that can be used as a biotechnological tool in susceptible crops. From the immense diversity of plant symbionts, those found in extreme environments such as Antarctica seems to be the ones with most potential since they (and their host) evolved in harsh and stressful conditions. We evaluated the effect of the inoculation with a consortium of plant growth-promoting rhizobacteria (PGPB) and endosymbiotic fungi isolated from an Antarctic plant on saline stress tolerance in different crops. To test this we established 4 treatments: (i) uninoculated plants with no saline stress, (ii) uninoculated plants subjected to saline stress (200 mM NaCl), (iii) plants inoculated with the microorganism consortium with no saline stress, and (iv) inoculated plants subjected to saline stress. First, we assessed the effect of symbiont consortium on survival of four different crops (cayenne, lettuce, onion, and tomato) in order to obtain a more generalized response of this biological interaction. Second, in order to deeply the mechanisms involved in salt tolerance, in lettuce plants we measured the ecophysiological performance (Fv/Fm) and lipid peroxidation to estimate the impact of saline stress on plants. We also measured proline accumulation and NHX1 antiporter gene expression (involved in Na+ detoxification) to search for possible mechanism of stress tolerance. Additionally, root, shoot, and total biomass was also obtained as an indicator of productivity. Overall, plants inoculated with microorganisms from Antarctica increased the fitness related traits in several crops. In fact, three of four crops selected to assess the general response increased its survival under salt conditions compared with those uninoculated plants. On the other hand, saline stress negatively impacted all measured trait, but inoculated plants were significantly less affected. In control osmotic conditions, there were no differences in proline accumulation and lipid peroxidation between inoculation treatments. Interestingly, even in control salinity, Fv/Fm was higher in inoculated plants after 30 and 60 days. Under osmotic stress, Fv/Fm, proline accumulation and NHX1 expression was significantly higher and lipid peroxidation lower in inoculated plants compared to uninoculated individuals. Moreover, inoculated plants exposed to saline stress had a similar final biomass (whole plant) compared to individuals under no stress. We conclude that Antarctic extremophiles can effectively reduce the physiological impact of saline stress in a salt-susceptible crops and also highlight extreme environments such as Antarctica as a key source of microorganism with high biotechnological potential.

Mutualistic symbiosis with fungal endophytes has been suggested as a possible mechanism for extreme environment colonization by Antarctic vascular plants. Fungal endophytes improve plant stress tolerance and performance by increasing plant hormone production and the uptake of water and nutrients. However, there are still gaps regarding the mechanisms by which these process ocurr. This work explores the role of root fungal endophytes in the production of exolytic enzymes involved in endophyte-mediated mineralization and nutrient uptake, as well as their impact on the performance of Antarctic plants. Hence, we evaluated the ability of fungal endophytes isolated from the two native Antarctic vascular plants, Colobanthus quitensis and Deschampsia antarctica, to enzymatically degrade different nutrient sources, mediate nitrogen mineralization and enhance growth of the host plant. Single-spore derived isolates were identified using molecular and morphological approaches. Penicillium chrysosgenum and Penicillium brevicompactum were identified as the dominant root endophytes in C. quitensis and D. antarctica, respectively. Root endophytes exhibited hydrolytic and oxidative enzymatic activities involved in carbohydrate or protein breakdown and phosphorus solubilization. In addition, the rates and porcentages of nitrogen mineralization, as well as the final total biomass were significantly higher in C. quitensis and D. antarctica individuals with root endophytes relative to those without endophytes. Our findings suggest that root endophytes exert a pivotal ecological role based not only on their capability to breakdown different nutrient sources but also accelerating nitrogen mineralization, improving nutrient acquisition and promoting plant growth in limited nutrient soils in Antarctic terrestrial ecosystems

In landscape genetics, model selection procedures based on Information Theoretic and Bayesian principles have been used with multiple regression on distance matrices (MRM) to test the relationship between multiple vectors of pairwise genetic, geographic, and environmental distance. Using Monte Carlo simulations, we examined the ability of model selection criteria based on Akaike's information criterion (AIC), its small-sample correction (AICc), and the Bayesian information criterion (BIC) to reliably rank candidate models when applied with MRM while varying the sample size. The results showed a serious problem: all three criteria exhibit a systematic bias toward selecting unnecessarily complex models containing spurious random variables and erroneously suggest a high level of support for the incorrectly ranked best model. These problems effectively increased with increasing sample size. The failure of AIC, AICc, and BIC was likely driven by the inflated sample size and different sum-of-squares partitioned by MRM, and the resulting effect on delta values. Based on these findings, we strongly discourage the continued application of AIC, AICc, and BIC for model selection with MRM.

The knowledge derived from Antarctic ecology may be fundamental for facing the complex environmental future of the world. As an early-warning system, a deep understanding of Antarctic ecosystems is therefore needed, but Antarctic ecology as a field is still very young and currently under consolidation. Around the world, 55 nations are involved in this task through their research programs, and, considering the importance of this joint effort, we evaluate some basic trends of their publications through a wide bibliographical review of Antarctic ecology. All ecology-related Antarctic papers published for 106 years (1904–2010) were reviewed. A lack of population and ecosystem research was observed, even in Animalia, the most studied kingdom. The publications originated mainly in developed countries; however, emerging countries have increased their participation in recent years. The current trends of Antarctic ecology as a field show a constant but low representation in both Antarctic science and ecology.Keywords: Antarctic ecology, scientific publications, Antarctic research, international territorial administration, Web of Science

Antarctica is a highly interesting region for ecologists because of its extreme climatic conditions and the uniqueness of its species. In this article, we describe the trends in Antarctic ecological research participation by Latin American countries. In a survey of articles indexed by the ISI Web of Science, we searched under the categories ‘‘Ecology,’’ ‘‘Biodiversity Conservation’’ and ‘‘Evolutionary Biology’’ and found a total of 254 research articles published by Latin American countries. We classified these articles according to the country of affiliation, kingdom of the study species, level of biological organization and environment. Our main finding is that there is a steady increase in the relative contribution of Latin American countries to Antarctic ecological research. Within each category, we found that marine studies are more common than terrestrial studies. Between the different kingdoms, most studies focus on animals and most studies use a community approach. The leading countries in terms of productivity were Argentina, Chile and Brazil, with Argentina showing the highest rate of increase. Keywords: Antarctica; Argentina; Brazil; Chile; research trends; scientific productivity (Published: 17 September 2013) Citation: Polar Research 2013, 32 , 19993, http://dx.doi.org/10.3402/polar.v32i0.19993

The Drake Passage arises as a likely route for gene flow into Antarctica, as it is the shortest path between this continent and the rest of the world. Despite this, long-distance dispersion into Antarctica could be particularly complex for terrestrial biota. To compare the levels of genetic diversity between Antarctic and South American populations of the Antarctic pearlwort, Colobanthus quitensis, we conducted the first estimation of genetic diversity in this species using amplified fragment length polymorphism. Four populations across the Drake Passage were selected and their genetic composition was characterized. Differences among the levels of genetic diversity were found between the populations analysed as well as between their allelic identities. However, interestingly, their spatial distribution across the Drake Passage suggests a north-to-south gradient of increasing genetic diversity.

Most climate and environmental change models predict significant increases in temperature and precipitation by the end of the 21st Century, for which the current functional output of certain symbioses may also be altered. In this context we address the following questions: 1) How the expected changes in abiotic factors (temperature, and water) differentially affect the ecophysiological performance of the plant Colobanthus quitensis? and 2) Will this environmental change indirectly affect C. quitensis photochemical performance and biomass accumulation by modifying its association with fungal endophytes? Plants of C. quitensis from King George Island in the South Shetland archipelago (62°09' S), and Lagotellerie Island in the Antarctic Peninsula (65°53' S) were put under simulated abiotic conditions in growth chambers following predictive models of global climate change (GCC). The indirect effect of GCC on the interaction between C. quitensis and fungal endophytes was assessed in a field experiment carried out in the Antarctica, in which we eliminated endophytes under contemporary conditions and applied experimental watering to simulate increased precipitation input. We measured four proxies of plant performance. First, we found that warming (+W) significantly increased plant performance, however its effect tended to be less than watering (+W) and combined warming and watering (+T°+W). Second, the presence of fungal endophytes improved plant performance, and its effect was significantly decreased under experimental watering. Our results indicate that both biotic and abiotic factors affect ecophysiological performance, and the directions of these influences will change with climate change. Our findings provide valuable information that will help to predict future population spread and evolution through using ecological niche models under different climatic scenarios.

We studied the effect of larval host (two Convolvulus L. species, Convolvulaceae) on sexual size dimorphism and on the fitness consequences of adult feeding in the bruchid beetle Megacerus eulophus (Erichson) (Coleoptera: Bruchidae). Whereas Convolvulus chilensis Pers. occurs in low density in semiarid habitats, Convolvulus bonariensis Cav. occurs in less stressful environments and exhibits higher population density. Host plants neither differ in seed mass nor in seed nitrogen content, and there were no consistent host-associated differences in female fitness. Consequently, host quality was considered to be similar. Sexual size dimorphism, expressed as the female:male ratio of body size, was significantly greater in C. chilensis than in C. bonariensis . A greater female size in the C. chilensis population could be selectively advantageous due to higher survival during host-plant search in stressful environments. Female longevity was affected by food availability (starvation vs. honey-pollen solution) and by the interaction between food availability and larval host. Fed females lived longer than starved females. This trend was found in both hosts, but it was of greater magnitude in C. chilensis than in C. bonariensis . Fecundity was significantly affected by adult feeding and larval host, and marginally affected by their interaction. Fed females laid more eggs than starved females. However, the increase in fitness of fed females was greater in C. chilensis . Results might be explained by differential selection on plasticity in life-history traits in contrasting environments. Females in stressful environments should take a greater advantage of the transient availability of resources.

Nurse effects, which occur when one plant species enhances the survival or growth of another plant species, are predicted to be most relevant in stressful environments. These effects are particulary important during seedling establishment due to their vulnerability to both biotic and abiotic factors, such as herbivory and drought. Tolerance to herbivory reflects the degree to which plants are able to regrow and reproduce after damage, and should vary with resource availability. In the high Andes of central Chile, the cushion plant Laretia acaulis (Apiaceae) acts as a buffer against environmental stress, enhancing survival of several associated plant species. We hypothesized that tolerance to herbivory of seedlings growing inside the canopy of L. acaulis should be greater than that of seedlings growing outside the cushion plant. We conducted a field experiment to test this hypothesis for two native perennial species in the high Andes of central Chile: Hordeum comosum (Poaceae) and Haplopappus anthylloides (Asteraceae). Seedlings of each species were planted inside and outside L. acaulis cushions and half of them received manual damage (50 % foliar tissue removed). Seedlings growing inside the nurse species showed high survival independent of the damage treatment. Whereas position (inside or outside the cushion plant) did not affect tolerance of Haplopappus anthylloides, it significantly affected tolerance of Hordeum comosum. Thus, we found similar survival of damaged and control seedlings of H. comosum inside the cushions, but survival of damaged seedlings in the bare ground was lower than that of control seedlings. We verified the occurrence of nurse effects of Laretia acaulis on the establishment of both species, and detected enhancement of tolerance to damage in Hordeum comosum in this stressful habitatSe ha sugerido que el efecto nodriza, el cual se evidencia cuando una especie vegetal incrementa la supervivencia o el crecimiento de otra, es más relevante en ambientes estresantes. Este efecto sería particularmente importante durante el periodo de establecimiento de las plántulas debido a su alta vulnerabilidad a factores bióticos y abióticos como herbivoría y desecación. La tolerancia a la herbivoría evidencia la capacidad de las plantas de recrecer y reproducirse después del daño, pero esta capacidad es recurso-dependiente. En los Andes de Chile central, la planta en cojín Laretia acaulis (Apiaceae) atenúa el efecto del estrés ambiental, aumentando la supervivencia de diversas especies de plantas asociadas. Proponemos que las plántulas que se encuentren creciendo dentro de los cojines de L. acaulis deberían evidenciar niveles mayores de tolerancia en relación a aquellas plántulas creciendo fuera de los cojines. Para probar esta hipótesis se llevó a cabo un experimento de campo con dos especies nativas perennes: Hordeum comosum (Poaceae) y Haplopappus anthylloides (Asteraceae). Plántulas de ambas especies fueron sembradas dentro y fuera de los cojines de L. acaulis, y la mitad de ellas recibieron daño manual (50 % tejido foliar removido). En general, las plántulas que se encontraron creciendo dentro del cojín evidenciaron una mayor supervivencia independientemente del tratamiento de daño. A pesar de que la ubicación de las plántulas no afectó la respuesta en tolerancia por parte de H. anthylloides, sí afectó significativamente la tolerancia de H. comosum. Por lo tanto, encontramos valores similares para la supervivencia de plántulas de H. comosum dentro de los cojines, pero la supervivencia de plántulas dañadas fuera de los cojines fue significativamente menor que la de plántulas control. Se pudo evidenciar la ocurrencia de efecto nodriza por parte de L. acaulis sobre el establecimiento de ambas especies y conjuntamente un aumento en la tolerancia al daño para H. comosum en este hábitat estresante

The increase in temperature as consequence of the recent global warming has been reported to generate new ice-free areas in the Antarctic continent, facilitating the colonization and spread of plant populations. Consequently, Antarctic vascular plants have been observed extending their southern distribution. But as the environmental conditions toward southern localities become progressively more departed from the species’ physiological optimum, the ecophysiological responses and survival to the expected global warming could be reduced. However, if processes of local adaptation are the main cause of the observed southern expansion, those populations could appear constrained to respond positively to the expected global warming. Using individuals from the southern tip of South America, the South Shetland Islands and the Antarctic Peninsula, we assess with a long term experiment (three years) under controlled conditions if the responsiveness of Colobanthus quitensis populations to the expected global warming, is related with their different foliar traits and photoprotective mechanisms along the latitudinal gradient. In addition, we tested if the release of the stress condition by the global warming in these cold environments increases the ecophysiological performance. For this, we describe the latitudinal pattern of net photosynthetic capacity, biomass accumulation, and number of flowers under current and future temperatures respective to each site of origin after three growing seasons. Overall, was found a clinal trend was found in the foliar traits and photoprotective mechanisms in the evaluated C. quitensis populations. On the other hand, an asymmetric response to warming was observed for southern populations in all ecophysiological traits evaluated, suggesting that low temperature is limiting the performance of C. quitensis populations. Our results suggest that under a global warming scenario, plant populations that inhabiting cold zones at high latitudes could increase in their ecophysiological performance, enhancing the size of populations or their spread.

International audience; Climate change is rapidly degrading the conditions of crop production. For instance, increasing salinization and aridity is forecasted to increase in most parts of the world. As a consequence, new stress-tolerant species and genotypes must be identified and used for future agriculture. Stress-tolerant species exist but are actually underutilized and neglected. Many stress-tolerant species are indeed traditional crops that are only cultivated by farmers at a local scale. Those species have a high biodiversity value. Besides, the human population will probably reach nine billion within coming decades. To keep pace with population growth, food production must increase dramatically despite the limited availability of cultivable land and water. Here, we review the benefits of quinoa, Chenopodium quinoa Willd., a seed crop that has endured the harsh bioclimatic conditions of the Andes since ancient times. Although the crop is still mainly produced in Bolivia and Peru, agronomic trials and cultivation are spreading to many other countries. Quinoa maintains productivity on rather poor soils and under conditions of water shortage and high salinity. Moreover, quinoa seeds are an exceptionally nutritious food source, owing to their high protein content with all essential amino acids, lack of gluten, and high content of several minerals, e.g., Ca, Mg, Fe, and health-promoting compounds such as flavonoids. Quinoa has a vast genetic diversity resulting from its fragmented and localized production over the centuries in the Andean region, from Ecuador to southern Chile, and from sea level to the altiplano. Quinoa can be adapted to diverse agroecological conditions worldwide. Year 2013 has therefore been declared the International Year of Quinoa by the United Nations Food and Agriculture Organization. Here, we review the main characteristics of quinoa, its origin and genetic diversity, its exceptional tolerance to drought and salinity, its nutritional properties, the reasons why this crop can offer several ecosystem services, and the role of Andean farmers in preserving its agrobiodiversity. Finally, we propose a schematic model integrating the fundamental factors that should determine the future utilization of quinoa, in terms of food security, biodiversity conservation, and cultural identity.

Se ha sugerido que el efecto nodriza, el cual se evidencia cuando una especie vegetal incrementa la supervivencia o el crecimiento de otra, es mas relevante en ambientes estresantes. Este efecto seria particularmente importante durante el periodo de establecimiento de las plantulas debido a su alta vulnerabilidad a factores bioticos y abioticos como herbivoria y desecacion. La tolerancia a la herbivoria evidencia la capacidad de las plantas de recrecer y reproducirse despues del dano, pero esta capacidad es recurso-dependiente. En los Andes de Chile central, la planta en cojin Laretia acaulis (Apiaceae) atenua el efecto del estres ambiental, aumentando la supervivencia de diversas especies de plantas asociadas. Proponemos que las plantulas que se encuentren creciendo dentro de los cojines de L. acaulis deberian evidenciar niveles mayores de tolerancia en relacion a aquellas plantulas creciendo fuera de los cojines. Para probar esta hipotesis se llevo a cabo un experimento de campo con dos especies nativas perennes: Hordeum comosum (Poaceae) y Haplopappus anthylloides (Asteraceae). Plantulas de ambas especies fueron sembradas dentro y fuera de los cojines de L. acaulis, y la mitad de ellas recibieron dano manual (50 % tejido foliar removido). En general, las plantulas que se encontraron creciendo dentro del cojin evidenciaron una mayor supervivencia independientemente del tratamiento de dano. A pesar de que la ubicacion de las plantulas no afecto la respuesta en tolerancia por parte de H. anthylloides, si afecto significativamente la tolerancia de H. comosum. Por lo tanto, encontramos valores similares para la supervivencia de plantulas de H. comosum dentro de los cojines, pero la supervivencia de plantulas danadas fuera de los cojines fue significativamente menor que la de plantulas control. Se pudo evidenciar la ocurrencia de efecto nodriza por parte de L. acaulis sobre el establecimiento de ambas especies y conjuntamente un aumento en la tolerancia al dano para H. comosum en este habitat estresante

Because of its harsh environmental conditions and remoteness, Antarctica is often considered to be at low risk of plant invasion. However, an increasing number of reports have shown the presence and spread of non-native plants in Antarctica; it is therefore important to study which factors control the invasion process in this ecosystem. Here, we assessed the role of different human activities on the presence and abundance of the invasive Poa annua . In addition, we performed a reciprocal transplant experiment in the field, and a manipulative experiment of germination with P. annua and the natives Colobanthus quitensis and Deschampsia antarctica , in order to unravel the effects of physical soil disturbance on the establishment and survival of P. annua . We found a positive correlation between abundance of P. annua and level of soil disturbance, and that survival of P. annua was 33% higher in sites with disturbed soil than non-disturbed. Finally, we found that disturbance conditions increased germination for P. annua, whereas for native species germination in experimentally disturbed soil was either unchanged or reduced compared to undisturbed soil. Our results indicate that human activities that modify abiotic soil characteristics could play an important role in the abundance of this invasive species. If the current patterns of human activities are maintained in Antarctica, the establishment success and spread of P. annua could increase, negatively affecting native flora. Keywords : Alien species; Colobanthus quitensis ; Deschampsia antarctica ; human disturbance; Poa annua ; tourists. ( Published: 23 June 2014) Citation: Polar Research 2014, 33 , 21425, http://dx.doi.org/10.3402/polar.v33.21425