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Landscape connectivity among remnant populations of guanaco (Lama guanicoe Müller, 1776) in an arid region of Chile impacted by global change

Autores:

Espinoza, M. I., Gouin, N., Porcile, F. A. S., Aspe, D. L., & Bertin, A.

Resumen:

Connectivity between populations plays a key role in the long-term persistence of species in fragmented habitats. This is of particular concern for biodiversity preservation in drylands, since water limited landscapes are typically characterized by little suitable habitat cover, high habitat fragmentation, harsh matrices, and are being rapidly degraded at a global scale. In this study, we modelled landscape connectivity between 11 guanaco Lama guanicoe populations in Chile’s arid Norte Chico, a region that supports the last remnant coastal populations of this emblematic herbivore indigenous to South America. We produced a habitat suitability model to derive a regional surface resistance map, and used circuit theory to map functional connectivity, investigate the relative isolation between populations, and identify those that contribute most to the patch connectivity network. Predicted suitable habitat for L. guanicoe represented about 25% of the study region (i.e., 29,173 km2) and was heterogeneously distributed along a continuous stretch along the Andes, and discontinuous patches along the coast. As a result, we found that high connectivity current flows in the mid and high Andes formed a wide, continuous connectivity corridor, enabling connectivity between all high Andean populations. Coastal populations, in contrast, were more isolated. These groups demonstrate no inter-population connectivity between themselves, only with higher altitude populations, and for two of them, animal movement was linked to the effectiveness of wildlife crossings along the Pan-American highway. Our results indicate that functional connectivity is an issue of concern for L. guanicoe in Chile’s Norte Chico, implying that future conservation and management plans should emphasize strategies aimed at conserving functional connectivity between coastal and Andean populations, as well as the protection of habitat patches likely to act as stepping stones within the connectivity network.

Año: 2018

Palabras claves:

Referencia APA: Espinoza, M. I., Gouin, N., Porcile, F. A. S., Aspe, D. L., & Bertin, A. (2017). Landscape connectivity among remnant populations of guanaco (Lama guanicoe Müller, 1776) in an arid region of Chile impacted by global change. PeerJ PrePrints. https://doi.org/10.7717/peerj.4429

Population variation in drought-resistance strategies in a desert shrub along an aridity gradient: Interplay between phenotypic plasticity and ecotypic differentiation

Autores:

Carvajal, D. E., Loayza, A. P., Rios, R. S., Gianoli, E., & Squeo, F. A.

Resumen:

Adaptations to drought of deciduous and evergreen species in arid environments are associated with resource-acquisitive (drought avoidance) and resource-conservative (drought tolerance) strategies of water use, respectively. Few studies have addressed whether a single species can exhibit both drought avoidance and drought tolerance strategies along an aridity gradient, and none have evaluated the role of ecotypic differentiation and phenotypic plasticity in shaping such strategies. In the desert shrub Encelia canescens, distributed along an aridity gradient in the Atacama Desert, we hypothesized that populations located in sites with lower and more variable rainfall (northern populations) would exhibit patterns of trait means and plasticity reflecting a water-conservative strategy, while populations in less arid and less variable environments (southern populations) would exhibit a water-acquisitive strategy. We also tested the hypothesis that functional variation in trait means and plasticity are not alternative mechanisms of adaptation to the environment. In a common garden experiment using plants from seeds collected from six populations spanning the species distribution range we found that plants from the northern populations were smaller, had fewer leaves, lower photosynthetic rates and had higher plasticity for root:shoot ratios and lower plasticity for leaf shedding, suggesting a resource-conservative strategy compared to plants from the southern populations, which showed a resource-acquisitive strategy. We found no association between variation in trait means and plasticity, which indicates that these are not alternative mechanisms of plant adaptation to environmental variation. Results suggest that E. canescens populations have evolved different strategies to cope with drought stress depending on their location along the Atacama Desert’s aridity gradient. This gives us a better understanding of the ecological and evolutionary processes that drive phenotypic variation among populations.

Año: 2017

Palabras claves: Atacama desert, Arid environments, Drought resistance, Intraspecific variation, Phenotypic plasticity, Encelia canescens

Referencia APA: Carvajal, D. E., Loayza, A. P., Rios, R. S., Gianoli, E., & Squeo, F. A. (2017). Population variation in drought-resistance strategies in a desert shrub along an aridity gradient: Interplay between phenotypic plasticity and ecotypic differentiation. Perspectives in Plant Ecology, Evolution and Systematics, 29, 12-19. https://doi.org/10.1016/j.ppees.2017.10.001

Conspecific plants are better ‘nurses’ than rocks: consistent results revealing intraspecific facilitation as a process that promotes establishment in a hyper-arid environment

Autores:

Loayza, A. P., Herrera-Madariaga, M. A., Carvajal, D. E., García-Guzmán, P., & Squeo, F. A.

Resumen:


Harsh environmental conditions in arid ecosystems limit seedling recruitment to microhabitats under nurse structures, such as shrubs or rocks. These structures, however, do not necessarily afford the same benefits to plants because nurse rocks provide only physical nurse effects, whereas nurse plants can provide both physical and biological nurse effects. Nevertheless, if the nurse plant is a conspecific, the benefits it provides may be outweighed by higher mortality due to negative density-dependent processes; consequently, negative density-dependence is expected to limit plants from acting as nurses to their own seedlings. The degree to which an abiotic nurse may be more beneficial than a conspecific one remains largely unexplored. Here, we examine the role and elucidate the mechanisms by which conspecific plants and rocks promote plant establishment in a hyper-arid desert. For 4 years, we examined establishment patterns of Myrcianthes coquimbensis (Myrtaceae), a threatened desert shrub that recruits solely in rock cavities and under conspecific shrubs. Specifically, we characterized these microhabitats, as well as open interspaces for comparison, and conducted germination, seed removal and seedling survival experiments. Our results revealed that conspecific shrubs and nurse rocks modified environmental conditions in similar ways; soil and air temperatures were lower, and water availability was higher than in open interspaces. We found no evidence on negative density-dependent recruitment: seed removal was lowest and seedling emergence highest under conspecific plants, moreover seedling survival probabilities were similar in rock cavities and under conspecific plants. We conclude that the probability of establishment was highest under conspecific plants than in other microhabitats, contrasting what is expected under the Janzen–Connell recruitment model. We suggest that for species living in stressful environments, population regulation may be a function of positive density-dependence and intraspecific facilitation may be a process that promotes the persistence of some plant species within a community.

Año: 2017

Palabras claves:

Referencia APA: Loayza, A. P., Herrera-Madariaga, M. A., Carvajal, D. E., García-Guzmán, P., & Squeo, F. A. (2017). Conspecific plants are better ‘nurses’ than rocks: consistent results revealing intraspecific facilitation as a process that promotes establishment in a hyper-arid environment. AoB Plants, 9(6), plx056. https://doi.org/10.1093/aobpla/plx056

Uso del Test de Rendimiento Continuo de Conners para diferenciar niños normales y con TDAH en Chile.

Autores:

Salas-Bravo, S., Gonzalez-Arias, M., Araya-Piñones, A., Valencia-Jimenez, M., & Oyarce-Cortes, S.

Resumen:

El trastorno de déficit atencional con hiperactividad (TDAH) constituye uno de los cuadros de mayor prevalencia durante la niñez. El presente trabajo se focalizó en evaluar si el Test de Rendimiento Continuo de Conners era capaz de discriminar entre niños con y sin TDAH diagnosticados por el docente. Se conformó una muestra no probabilística de 30 niños escolares (15 clínicos y 15 normales) a través de la aplicación del cuestionario de atención. Todos los niños completaron la aplicación del test computarizado de Conners. Se observaron diferencias significativas entre la muestra normal y clínica. Todos los niños seleccionados como normales no encajaron el perfil clínico. Solo el 50% de los casos considerados con TDAH encajaron el perfil clínico. Se analizan las implicancias del sobre/diagnóstico del trastorno.

Año: 2017

Palabras claves: TDAH, Test de rendimiento continuo, Diagnóstico, Escalas diagnósticas

Referencia APA: Salas-Bravo, S., Gonzalez-Arias, M., Araya-Piñones, A., Valencia-Jimenez, M., & Oyarce-Cortes, S. (2017). Uso del Test de Rendimiento Continuo de Conners para diferenciar niños normales y con TDAH en Chile. Terapia Psicológica, 35(3), 283-291. https://scielo.conicyt.cl/pdf/terpsicol/v35n3/0716-6184-terpsicol-35-03-0283.pdf

Surface water quality in a sulfide mineral‐rich arid zone in North‐Central Chile: Learning from a complex past, addressing an uncertain future

Autores:

Flores, M., Núñez, J., Oyarzún, J., Freixas, G., Maturana, H., & Oyarzún, R.

Resumen:

This study presents an analysis of up to 30 years of hydrological variables and selected waterquality parameters (pH, SO4, Fe, Cu, and As) in the upper area of the Elqui River basin inNorth‐Central Chile. A correlation analysis determined statistically significant positive relation-ship for SO4‐Cu, Fe‐As, and Fe‐Cu. In terms of historical behaviour, no statistically significanttrends were detected for precipitation or temperature. In contrast, for flow, there is an overalldecreasing pattern for the entire area of study, although only in one case this trend was statisti-cally significant. Along with the aforementioned analysis, a characterization of the flow‐waterquality relationships is considered for the time period analyzed. Although erratic behaviours wereconfirmed, a negative (i.e., inverse) flow‐concentration relationship was identified for SO4, a pos-itive (i.e., direct) relationship for Fe, and undefined relationships for As and Cu were obtained.From these analyses and based on previous studies on projections regarding climate change forthe Andean region, and in particular for the upper Elqui zone, an estimation of the possible effectsof the change in water regimes on water quality in the area of study is developed. It is likely that adecrease in surface flow, as a consequence of climate change could translate into improvementsin water quality in terms of Fe and eventually As and Cu, but into an impairment in the case ofSO4. In any case, this is a complex situation that demands special attention in the face of indus-trial activities that could be developed in tributaries like the Claro River, which currently play animportant role in depurating or diluting contaminants in the waters of the Elqui River. Finally, itshould be noted that this study addresses an issue that goes beyond the local interest and couldbe used as a reference to compare other transitional environments containing sulphide ores orareas of hydrothermal alterations, which are considered to be highly vulnerable to climate changeand variability.

Año: 2016

Palabras claves: Acid rock drainage, Andean river, arid zone, Coquimbo region

Referencia APA: Flores, M., Núñez, J., Oyarzún, J., Freixas, G., Maturana, H., & Oyarzún, R. (2017). Surface water quality in a sulfide mineral‐rich arid zone in North‐Central Chile: Learning from a complex past, addressing an uncertain future. Hydrological Processes, 31(3), 498-513. http://doi.dx.org/10.1002/hyp.11086

A framework for the classification Chilean terrestrial ecosystems as a tool for achieving global conservation targets

Autores:

Martínez-Tilleria, K., Núñez-Ávila, M., León, C., Pliscoff, P., Squeo, F., & Armesto, J.

Resumen:

Countries that are signatories of the Convention of Biological Diversity are committed to the goal of protecting 17% of their natural ecosystems by 2020. The lack of an up-to-date, operational classification and cartography of regional ecosystems seriously limits the assessment of progress towards this goal. Here, we present a broad ecosystem framework, which combines land use, functional traits of dominant plant species, and climatic factors for the classification of terrestrial ecosystems and apply this framework to classify Chilean terrestrial ecosystems. This new classification is consistent with the recently proposed IUCN framework to assess ecosystem conservation status. Using this framework, we identified and described 30 Chilean terrestrial ecosystems, including land units of natural and anthropogenic origin. We also provide a cartographic representation of ecosystems for land planning purposes and an overall assessment of their conservation status. We evaluated the representation of the 30 ecosystems in the Chilean National System of Protected Areas (NSPA) and in Private Protected Areas (PPA), identifying 15 ecosystems underrepresented (below the 17% target) in the NSPA, in contrast to only 11 when the area of NSPA+PPA was considered. The proposed classification can be broadly applicable to assess the conservation status of ecosystems elsewhere, using similar conceptual and methodological tools. The development of functional ecosystem classifications for different countries must be encouraged to facilitate monitoring of global conservation targets.

Año: 2017

Palabras claves: Ecosystem approach, Biodiversity conservation, Functional traits, Protected areas

Referencia APA: Martínez-Tilleria, K., Núñez-Ávila, M., León, C., Pliscoff, P., Squeo, F., & Armesto, J. (2017). A framework for the classification Chilean terrestrial ecosystems as a tool for achieving global conservation targets. Biodiversity And Conservation, 26(12), 2857-2876. http://dx.doi.org/10.1007/s10531-017-1393-x

The importance of scale-dependent ravine characteristics on breeding-site selection by the Burrowing Parrot, Cyanoliseus patagonus

Autores:

Ramirez-Herranz, M., Rios, R., Vargas-Rodriguez, R., Novoa-Jerez, J. and Squeo, F.

Resumen:

In birds, the environmental variables and intrinsic characteristics of the nest have important fitness consequences through its influence on the selection of nesting sites. However, the extent to which these variables interact with variables that operate at the landscape scale, and whether there is a hierarchy among the different scales that influences nest-site selection, is unknown. This interaction could be crucial in burrowing birds, which depend heavily on the availability of suitable nesting locations. One representative of this group is the burrowing parrot, Cyanoliseus patagonus that breeds on specific ravines and forms large breeding colonies. At a particular site, breeding aggregations require the concentration of adequate environmental elements for cavity nesting, which are provided by within ravine characteristics. Therefore, intrinsic ravine characteristics should be more important in determining nest site selection compared to landscape level characteristics. Here, we assess this hypothesis by comparing the importance of ravine characteristics operating at different scales on nest-site selection and their interrelation with reproductive success. We quantified 12 characteristics of 105 ravines in their reproductive habitat. For each ravine we quantified morphological variables, distance to resources and disturbance as well as nest number and egg production in order to compare selected and non-selected ravines and determine the interrelationship among variables in explaining ravine differences. In addition, the number of nests and egg production for each reproductive ravine was related to ravine characteristics to assess their relation to reproductive success. We found significant differences between non-reproductive and reproductive ravines in both intrinsic and extrinsic characteristics. The multidimensional environmental gradient of variation between ravines, however, shows that differences are mainly related to intrinsic morphological characteristics followed by extrinsic variables associated to human disturbance. Likewise, within reproductive ravines, intrinsic characteristics are more strongly related to the number of nests. The probability of producing eggs, however, was related only to distance to roads and human settlements. Patterns suggest that C. patagonus mainly selects nesting sites based on intrinsic morphological characteristics of ravines. Scale differences in the importance of ravine characteristics could be a consequence of the particular orography of the breeding habitat. The arrangement of resources is associated to the location of the gullies rather than to individual ravines, determining the spatial availability and disposition of resources and disturbances. Thus, nest selection is influenced by intrinsic characteristics that maximize the fitness of individuals. Scaling in nest-selection is discussed under an optimality approach that partitions patch selection based on foraging theory.

Año: 2017

Palabras claves: Nesting site, Burrowing bird, Intrinsic morphological characteristic, Foraging, Landscape variables.

Referencia APA: Ramirez-Herranz, M., Rios, R., Vargas-Rodriguez, R., Novoa-Jerez, J. and Squeo, F. (2017). The importance of scale-dependent ravine characteristics on breeding-site selection by the Burrowing Parrot, Cyanoliseus patagonus. PeerJ, 5, p.e3182. https://doi.org/10.7717/peerj.3182

Genetic variation of loci potentially under selection confounds species–genetic diversity correlations in a fragmented habitat

Autores:

Bertin, A., Gouin, N., Baumel, A., Gianoli, E., Serratosa, J., Osorio, R. and Manel, S.

Resumen:

Positive species–genetic diversity correlations (SGDCs) are often thought to result from the parallel influence of neutral processes on genetic and species diversity. Yet, con-founding effects of non-neutral mechanisms have not been explored. Here, we investigate the impact of non-neutral genetic diversity on SGDCs in high Andean wetlands.We compare correlations between plant species diversity and genetic diversity (GD)calculated with and without loci potentially under selection (outlier loci). The study system includes 2188 specimens from five species (three common aquatic macroinvertebrate and two dominant plant species) that were genotyped for 396 amplified fragment length polymorphism loci. We also appraise the importance of neutral processes onSGDCs by investigating the influence of habitat fragmentation features. Significant positive SGDCs were detected for all five species (mean SGDC = 0.52  0.05). While only a few outlier loci were detected in each species, they resulted in significant decreases in GD and in SGDCs. This supports the hypothesis that neutral processes drive species–genetic diversity relationships in high Andean wetlands. Unexpectedly, the effects on genetic diversity GD of the habitat fragmentation characteristics in this study increased with the presence of outlier loci in two species. Overall, our results reveal pitfalls in using habitat features to infer processes driving SGDCs and show that a few loci potentially under selection are enough to cause a significant downward bias in SGDC. Investigating confounding effects of outlier loci thus represents a useful approach to evidence the contribution of neutral processes on species–genetic diversity relationships.

Año: 2017

Palabras claves: Community genetics, connectivity, habitat, high Andean wetlands, outlier loci,species–genetic diversity correlations.

Referencia APA: Bertin, A., Gouin, N., Baumel, A., Gianoli, E., Serratosa, J., Osorio, R. and Manel, S. (2017). Genetic variation of loci potentially under selection confounds species-genetic diversity correlations in a fragmented habitat. Molecular Ecology, 26(2), pp.431-443. dx.doi.org/10.1111/mec.13923

Rootstock effect on irrigated grapevine yield under arid climate conditions are explained by changes in traits related to light absorption of the scion

Autores:

Bascuñán-Godoy, L., Franck, N., Zamorano, D., Sanhueza, C., Carvajal, D., & Ibacache, A.

Resumen:


The purpose of this study was to investigate the mechanisms underlying the effect of rootstocks on table grapevines grown under irrigated conditions in the arid North macro-zone of Chile.

Grapevine cv. Red Globe grafted onto three rootstocks (Harmony, Saint George and Salt Creek) were studied Structural and physiological parameters were monitored at different phenological stages under optimal production conditions.

An outstanding yield increment brought about by the rootstocks Harmony and Salt Creek was correlated with increased individual leaf and specific leaf area, pruning weight (proxy for total leaf area), photosynthesis per unit leaf mass, sugar in leaves and root carbon reserves. In addition, these high yielding rootstocks induced higher contents of light-harvesting chlorophyll a/b protein of photosystem II and total chlorophyll in the leaves of the scion. No correlations of yield with traits involved in water use (relative water content or instantaneous water use efficiency) were observed.

The effects of rootstocks on the light capture capacity of the scion directly affected carbon assimilation and storage and, accordingly, yield. Therefore, the identified traits are valuable targets for screening and selecting yield efficient rootstocks for irrigated table grape production in arid zones.

Año: 2017

Palabras claves: Grapevine rootstock, Light capture, Photo synthesis, Pruning weight, Red Globe, Yield

Referencia APA: Bascuñán-Godoy, L., Franck, N., Zamorano, D., Sanhueza, C., Carvajal, D., & Ibacache, A. (2017). Rootstock effect on irrigated grapevine yield under arid climate conditions are explained by changes in traits related to light absorption of the scion. Scientia Horticulturae, 218, 284-292. http://dx.doi.org/10.1016/j.scienta.2017.02.034

Surface water quality in a sulfide mineral-rich arid zone in North-Central Chile: Learning from a complex past, addressing an uncertain future

Autores:

Flores, M., Núñez, J., Oyarzún, J., Freixas, G., Maturana, H., & Oyarzún, R.

Resumen:

This study presents an analysis of up to 30 years of hydrological variables and selected water quality parameters (pH, SO4, Fe, Cu, and As) in the upper area of the Elqui River basin in North‐Central Chile. A correlation analysis determined statistically significant positive relationship for SO4‐Cu, Fe‐As, and Fe‐Cu. In terms of historical behaviour, no statistically significant
trends were detected for precipitation or temperature. In contrast, for flow, there is an overall decreasing pattern for the entire area of study, although only in one case this trend was statistically significant. Along with the aforementioned analysis, a characterization of the flow‐water quality relationships is considered for the time period analyzed. Although erratic behaviours were confirmed, a negative (i.e., inverse) flow‐concentration relationship was identified for SO4, a positive (i.e., direct) relationship for Fe, and undefined relationships for As and Cu were obtained.
From these analyses and based on previous studies on projections regarding climate change for the Andean region, and in particular for the upper Elqui zone, an estimation of the possible effects of the change in water regimes on water quality in the area of study is developed. It is likely that a decrease in surface flow, as a consequence of climate change could translate into improvements in water quality in terms of Fe and eventually As and Cu, but into an impairment in the case of
SO4. In any case, this is a complex situation that demands special attention in the face of industrial activities that could be developed in tributaries like the Claro River, which currently play an important role in depurating or diluting contaminants in the waters of the Elqui River. Finally, it should be noted that this study addresses an issue that goes beyond the local interest and could be used as a reference to compare other transitional environments containing sulphide ores or areas of hydrothermal alterations, which are considered to be highly vulnerable to climate change and variability.

Año: 2017

Palabras claves: acid rock drainage, Andean river, arid zone, Coquimbo region

Referencia APA: Flores, M., Núñez, J., Oyarzún, J., Freixas, G., Maturana, H., & Oyarzún, R. (2016). Surface water quality in a sulfide mineral-rich arid zone in North-Central Chile: Learning from a complex past, addressing an uncertain future. Hydrological Processes, 31(3), 498-513. http://dx.doi.org/10.1002/hyp.11086

Rainfall, microhabitat, and small mammals influence the abundance and distribution of soil microorganisms in a Chilean semi-arid shrubland.

Autores:

Aguilera, L., Armas, C., Cea, A., Gutiérrez, J., Meserve, P., & Kelt, D.

Resumen:

Patterns in rainfall and soil water availability are considered to be the main drivers governing arid and semiarid ecosystems. While the mechanisms by which water limits aboveground net primary production has been widely explored, few long-term studies have examined interactions between precipitation, soil resources, plant communities, and soil microbial communities; these may be critical to understanding soil biogeochemical cycles and above- and belowground interactions. We capitalized on a long-term biotic manipulation (exclusion of small mammal herbivores from replicate plots) and long-term variation in rainfall to assess how precipitation, small mammals, and shrub cover act directly and interactively to influence the spatial and temporal distribution of soil microorganisms, a key first step to understanding soil biogeochemical cycles. We measured the abundance of arbuscular mycorrhiza (AM), soil fungi, soil bacteria, and soil physicochemical characteristics over 10 consecutive years in a semiarid thorn scrub community in north–central Chile; we sampled two microhabitats (under shrub cover, and in open spaces between shrubs colonized by ephemeral plants), and in plots with or without the presence of native small mammals, the main herbivores in this environment. Annual rainfall ranged widely (11–356 mm) in this period and was the primary factor affecting abundance of AM root colonization and soil microbes. While the percentage of root length with AM was higher in dry compared to wet years, free-living soil bacteria and fungi were more abundant during wet years. All microorganisms were more abundant in the resource islands beneath the shrubs compared to open microhabitat between shrubs, although the relation between soil biota and the concentration of some particular nutrients was negative. These patterns were modulated by the presence of small mammals, which enhanced root colonization by AM fungi, particularly for ephemeral plants, but which were negatively associated with soil fungi abundance. The abundance of soil bacteria showed a more complex response to the presence of small mammals and was dependent on microhabitat and year. The spatial and temporal heterogeneity of soil resources and the activity of small mammals are important modulators of subterranean biotic responses to rainfall, the primary factor affecting soil microbiota abundance in this semiarid ecosystem.

Año: 2016

Palabras claves: ENSO; LTSER; Plant-soil interactions; Mycorrhizal fungi; Soil filamentous fungi; Soil heterotrophic bacteria; Soil yeasts.

Referencia APA: Aguilera, L., Armas, C., Cea, A., Gutiérrez, J., Meserve, P., & Kelt, D. (2016). Rainfall, microhabitat, and small mammals influence the abundance and distribution of soil microorganisms in a Chilean semi-arid shrubland. Journal Of Arid Environments, 126, 37-46.

Shrub–ephemeral plants interactions in semiarid north-central Chile: Is the nurse plant syndrome manifested at the community level?.

Autores:

Madrigal-González, J., Kelt, D., Meserve, P., Squeo, F., & Gutiérrez, J.

Resumen:

Models of plant–plant interactions suggest that nurse plants are critical for the maintenance of biodiversity and ecosystem functions in arid and semiarid lands. At the community scale, however, empirical support of this idea is limited and context-dependent. Following on a preliminary work which suggested that a dominant shrub in north-central Chile (Porlieria chilensis) had nurse plant effects, we tested the effects of this and two other shrubs (Adesmia bedwellii and Proustia cuneifolia) on community biomass production, species density, and species composition of ephemeral plants in the semiarid scrub of the Bosque Fray Jorge National Park (Chile) over four consecutive years. We tested for main and interactive effects of shrubs and precipitation on total biomass production and species density of ephemeral plant communities using Generalized Linear Mixed Models (GLMM). To analyze the effects of shrubs and precipitation on species composition we used Canonical Correspondence Analysis (CCA) and t-value biplot analysis. Total biomass production increased significantly with precipitation and was consistently lower beneath shrub canopies, particularly under A. bedwellii and P. chilensis. Although ephemeral plant species density generally was higher in open areas, differences between open and shrub canopy samples diminished with increasing precipitation. Finally, despite significant differences in ephemeral plant species composition between open areas and shrub canopies, we found no evidence of shrub species-specific effects. In conclusion, our results do not support a classical nurse plant syndrome in the semiarid scrub of the Bosque Fray Jorge National Park although shrubs can increase local diversity by favoring some ephemeral plant species that are absent in open areas.

Año: 2016

Palabras claves: Ephemeral plant communities; Facilitation; Nurse plant syndrome; Precipitation; Semiarid scrub; Biomass production; Diversity.

Referencia APA: Madrigal-González, J., Kelt, D., Meserve, P., Squeo, F., & Gutiérrez, J. (2016). Shrub–ephemeral plants interactions in semiarid north-central Chile: Is the nurse plant syndrome manifested at the community level?. Journal Of Arid Environments, 126, 47-53.