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The rise and demise of plastic shopping bags in Chile – Broad and informal coalition supporting ban as a first step to reduce single-use plastics

Autores:

Amenábar Cristi, M., Holzapfel, C., Nehls, M., De Veer, D., Gonzalez, C., & Holtmann, G., Honorato-Zimmer, D., Kiessling, T., Leyton Munoz, A., Narvaez Reyes, S., Nunez, P., Sepulveda, J.M., Vásquez, N., Thiel, M.

Resumen:

Single-use plastic bags (SUPBs) were introduced to society as a way to facilitate our daily lives, but due to their low post-use value they are found as litter in many different environments, from urban to rural and remote, natural environments. Given the increasing awareness about environmental litter, many communities have banned SUPBs in the recent past. Here we explore an emerging economy to document the rise and demise of SUPBs in society. Through a review of scientific and grey literature (including governmental documents and media coverage) we reconstruct the timeline of SUPBs in Chile, including the development of the plastic industry and retail business within Chile, the introduction, spread and finally the demise of SUPBs. Focused on the demise phase, we document the creation and succession of municipal ordinances to reduce SUPBs in local commerce, and the development of a national law to regulate the use of SUPBs. In order to document the involvement of the general public during the demise phase, we also examined current behavior and behavioral intentions of people in (i) a local project introducing reusable cloth bags to reduce the use of SUPBs, and (ii) a consumer survey about public perception of SUPBs and their use. Plastic bags were introduced in Chile in the 1970s, then spread with the emergence of supermarkets and retail stores in the 1980s and 1990s, and were widely used in commerce by the turn of the century. During the first decade of the 21st century the first scientific studies reported large amounts of plastic litter and high proportions of single-use plastics in coastal environments, public awareness grew, and numerous initiatives aiming to reduce consumption and littering of plastics developed. The first municipal ban of SUPBs in 2013 was emulated during the following five years by 62 other Chilean municipalities and in 2018 translated into a national law, which was highly approved and supported by the population. We conclude that the ban of SUBPs in Chile was facilitated by a broad concern among the general public, which led to a bottom-up movement culminating in the national government taking stakes in the issue. Finally, we argue that this can only be a first step that must be followed by further actions to abolish single-use products in order to effectively protect the environment and in particular the world's oceans.

Año: 2019

Palabras claves: Marine litter, Willingness to engage, Socio-economic factors, Pro-environmental behavior, Waste management.

Referencia APA: Amenábar Cristi, M., Holzapfel, C., Nehls, M., De Veer, D., Gonzalez, C., & Holtmann, G., Honorato-Zimmer, D., Kiessling, T., Leyton Munoz, A., Narvaez Reyes, S., Nunez, P., Sepulveda, J.M., Vásquez, N., Thiel, M. (2019). The rise and demise of plastic shopping bags in Chile – Broad and informal coalition supporting ban as a first step to reduce single-use plastics. Ocean & Coastal Management, 105079. doi: 10.1016/j.ocecoaman.2019.105079

Seasonal Variability of the Southern Tip of the Oxygen Minimum Zone in the Eastern South Pacific (30°‐38°S): A Modeling Study

Autores:

Pizarro‐Koch, M., Pizarro, O., Dewitte, B., Montes, I., Ramos, M., Paulmier, A., & Garçon, V.

Resumen:

We investigate the seasonal variability of the southern tip (30°–38°S) of the eastern South Pacific oxygen minimum zone (OMZ) based on a high horizontal resolution (1/12°) regional coupled physical‐biogeochemical model simulation. The simulation is validated by available in situ observations and the OMZ seasonal variability is documented. The model OMZ, bounded by the contour of 45 μM, occupies a large volume (4.5x104 km3) during the beginning of austral winter and a minimum (3.5x104 km3) at the end of spring, just 1 and 2 months after the southward transport of the Peru‐Chile Undercurrent (PCUC) is maximum and minimum, respectively. We showed that the PCUC significantly impacts the alongshore advection of dissolved oxygen (DO) modulating the OMZ seasonal variability. However, zonal transport of DO by meridionally alternating zonal jets and mesoscale eddy fluxes play also a major role in the seasonal and spatial variability of the OMZ. Consistently, a DO budget analysis reveals a significant contribution of advection terms to the rate of change of DO and the prominence of mesoscale variability within the seasonal cycle of these terms. Biogeochemical processes and horizontal and vertical mixing, associated with subgrid scale processes, play only a secondary role in the OMZ seasonal cycle. Overall, our study illustrates the interplay of mean and (mesoscale) eddy‐induced transports of DO in shaping the OMZ and its seasonal cycle off Central Chile.

Año: 2019

Palabras claves: Oxygen minimum zone, Eddy fluxes, Peru‐Chile Undercurrent, Oxygen budget, Eastern South Pacific

Referencia APA: Pizarro‐Koch, M., Pizarro, O., Dewitte, B., Montes, I., Ramos, M., Paulmier, A., & Garçon, V. (2019). Seasonal Variability of the Southern Tip of the Oxygen Minimum Zone in the Eastern South Pacific (30°‐38°S): A Modeling Study. Journal Of Geophysical Research: Oceans, 124(12), 8574-8604. doi: 10.1029/2019jc015201

Antagonistic interplay between pH and food resources affects copepod traits and performance in a year-round upwelling system

Autores:

Aguilera, V., Vargas, C., & Dam, H.

Resumen:

Linking pH/pCO2 natural variation to phenotypic traits and performance of foundational species provides essential information for assessing and predicting the impact of ocean acidification (OA) on marine ecosystems. Yet, evidence of such linkage for copepods, the most abundant metazoans in the oceans, remains scarce, particularly for naturally corrosive Eastern Boundary Upwelling systems (EBUs). This study assessed the relationship between pH levels and traits (body and egg size) and performance (ingestion rate (IR) and egg reproduction rate (EPR)) of the numerically dominant neritic copepod Acartia tonsa, in a year-round upwelling system of the northern (23° S) Humboldt EBUs. The study revealed decreases in chlorophyll (Chl) ingestion rate, egg production rate and egg size with decreasing pH as well as egg production efficiency, but the opposite for copepod body size. Further, ingestion rate increased hyperbolically with Chl, and saturated at ~1 µg Chl. L−1. Food resources categorized as high (H, >1 µg L−1) and low (L, <1 µg L−1) levels, and pH-values categorized as equivalent to present day (≤400 µatm pCO2, pH > 7.89) and future (>400 µatm pCO2, pH < 7.89) were used to compare our observations to values globally employed to experimentally test copepod sensitivity to OA. A comparison (PERMANOVA) test with Chl/pH (2*2) design showed that partially overlapping OA levels expected for the year 2100 in other ocean regions, low-pH conditions in this system negatively impacted traits and performance associated with copepod fitness. However, interacting antagonistically with pH, food resource (Chl) maintained copepod production in spite of low pH levels. Thus, the deleterious effects of ocean acidification are modulated by resource availability in this system.

Año: 2020

Palabras claves:

Referencia APA: Aguilera, V., Vargas, C., & Dam, H. (2020). Antagonistic interplay between pH and food resources affects copepod traits and performance in a year-round upwelling system. Scientific Reports, 10(1). doi: 10.1038/s41598-019-56621-6

Can hydraulic traits help to explain the current distributional limits in two Nothofagus species in the Chilean Andes?

Autores:

Carrasco-Urra, F., Saldaña, A., Molina-Montenegro, M.A.

Resumen:

The Andes of central Chile is a geographical gradient with a marked variation in its climatic conditions. Along its
slopes, are distributed the evergreen Nothofagus dombeyi and deciduous Nothofagus pumilio species that show
differences in their leaf habits, range extensions, and in their limits of latitudinal distribution. Plant ecology
proposes that unfavorable climatic conditions are limiting factors that determine the tree species distributions
and that the functional hydraulic traits responses allow understanding the mechanisms underlying the current
distribution of them. We hypothesize that both species will have lower mean values of KL and KS in populations
near to distribution limits compared with middle populations due that unfavorable climatic conditions are
predominant in the latitudinal range limits. We quantify in situ the leaf (KL) and xylem (KS) specific hydraulic conductivities in populations of N. dombeyi and N. pumilio near their northern and southern limits of distribution
as well as in a middle population along Chilean Andes. Results showed that both species had lower mean values
in populations near northern and southern limits compared to populations distributed in middle sites. Also, we
found that the hydraulic performance population of N. pumilio distributed in the middle site had higher than
N. dombeyi. We concluded that lower hydraulic conductivity associated with distribution limits for both study
species implies a lower probability of being affected by embolism, independently of their leaf habits, showing a
functional hydraulic convergence to low water availability or cold.

Año: 2019

Palabras claves: embolism, evergreen vs deciduous, hydraulic traits, Nothofagus , species distribution.

Referencia APA: Carrasco-Urra, F., Saldaña, A., Molina-Montenegro, M.A. (2019). Can hydraulic traits help to explain the current distributional limits in two Nothofagus species in the Chilean Andes?. Gayana Bot. vol. 76, No. 2, 237-246

DOI:

An analysis of modern pollen rain on an elevational gradient in the High-Andes of Central Chile (33°)

Autores:

Fernández Murillo, M.P., Cuevas, J.G., Maldonado, A.

Resumen:

The superficial pollen records are tools for the vegetal reconstruction of a certain area. Like a plant record,
pollen can be used to classify plant formations and determine plant diversity. Although some studies show the
relationship between pollen and vegetation in Chile, few have explored the pollen diversity in an altitudinal
gradient and its sensitivity as a marker of altitudinal belts. Consequently, we used pollen samples of surface soil
and by means of morphological identification, cluster analysis and zonation we determined the pollen groups
that represent the vegetation floors in an altitudinal gradient. Moreover, we compared pollen diversity among
these floors for three basins of the Chilean Central Andes as a comprehensive index of the pollen composition
and abundance. In the Laguna del Viento basin, four pollen groups coincided with the plant floors previously defined in the literature: sub Andean, Andean, and High Andean. The latter one was subdivided into two groups.
In the El Yeso basin, two pollen groups were determined, all corresponding to the Andean floor, and finally in
the El Volcán basin, two pollen groups were recorded that are related to the sub Andean and Andean vegetation
floors. On the other hand, only in one basin the pollen diversity decreased with the altitude. These results
showed that pollen assemblages can distinguish plant floors, but with a lower resolution than when using
established flora, probably due to the pollen taxonomic resolution, differential production and dispersal factors.

Año: 2019

Palabras claves: Altitude, Andes of Central Chile, diversity, pollen, vegetal distribution.

Referencia APA: Fernández Murillo, M.P., Cuevas, J.G., Maldonado, A. (2019).An analysis of modern pollen rain on an elevational gradient in the High-Andes of Central Chile (33°). Gayana Bot. vol. 76, No. 2, 220-23.

DOI:

Molecular characterization and expression patterns of two LPS binding /bactericidal permeability-increasing proteins (LBP/BPIs) from the scallop Argopecten purpuratus.

Autores:

González, R., Brokordt, K., Rojas, R., & Schmitt, P.

Resumen:

Lipopolysaccharide-binding proteins (LBPs) and bactericidal permeability-increasing proteins (BPIs) are effec-
tors of the innate immune response which act in a coordinated manner to bind and neutralize the LPS present in

Gram negative bacteria. The structural organization that confers the function of LBPs and BPIs is very similar,
however, they are antagonistic to each other. In this work, we characterized two LBP/BPIs from the scallop
Argopecten purpuratus, namely ApLBP/BPI1 and ApLBP/BPI2. The molecular and phylogenetic analyses of
ApLBP/BPIs indicated that both isoforms display classic characteristics of LBP/BPIs from other invertebrates.

Additionally, ApLBP/BPIs are constitutively expressed in scallop tissues and their transcript expression is up-
regulated in hemocytes and gills in response to an immune challenge. However, some structural characteristics

of functional importance for the biological activity of these molecules, such as the net charge differ substantially
between ApLBP/BPI1 and ApLBP/BPI2. Furthermore, each isoform displays a specific profile of basal expression
among different tissues, as well as specific patterns of expression during the activation of the immune response.
Results suggest that functional specialization of ApLBP/BPIs might happen, with potential role as LBP or BPI in
this species of scallop. Further research on the biological activities of ApLBP/BPIs are necessary to elucidate their
participation in the scallop immune response.

Año: 2020

Palabras claves: Innate immunity, Antimicrobial effectors, Mollusks, Scallops, Aquaculture

Referencia APA: González, R., Brokordt, K., Rojas, R., & Schmitt, P. (2020). Molecular characterization and expression patterns of two LPS binding /bactericidal permeability-increasing proteins (LBP/BPIs) from the scallop Argopecten purpuratus. Fish & Shellfish Immunology, 97, 12-17. doi: 10.1016/j.fsi.2019.12.032

Biochemical composition as a function of fruit maturity stage of bell pepper (Capsicum annum) inoculated with Bacillus amyloliquefaciens

Autores:

Cisternas-Jamet, J., Salvatierra-Martínez, R., Vega-Gálvez, A., Stoll, A., Uribe, E., & Goñi, M.

Resumen:

The use of growth promoting bacteria in sweet pepper plants (Capsicum annuum), such as some Bacillus strains,
has previously been related to increased yields and plant resistance. However, it is also important to evaluate the
effect that inoculation has on the ripening process and on the nutritional composition of the fruits. In the present
work, the effect of root inoculation of sweet pepper plants with Bacillus amyloliquefaciens on the composition of
sweet peppers harvested at different stages of maturation is evaluated. It was possible to determine a clear effect
of inoculation on the fixation of Ca and Fe, and the content of vitamin C and compounds with antioxidant
capacity. Root inoculation with Bacillus amyloliquefaciens generated an increase in the concentration of calcium,
iron and vitamin C of 561 mg kg−1, 182 mg kg−1 and 561 μg 100 g−1 d.m., respectively in Red II and Green I
compared to the control samples. An increase in antioxidant capacity was generated, which is reflected in an
increase in the ORAC test of 1618 umol TE 100 g−1 d.m. and in 587 umol TE 100 g−1 d.m. for Green I and Red I
crops respectively. On the other hand, the effect of the fruit ripening process was significant, especially in
relation to the development of natural pigments and phenolic compounds, with high antioxidant potential. An
increased of extractable pigments of 57 color units with respect to the control sample in Red II is highlighted,
which enhances the organoleptic attractiveness of the fruit. These results would allow producers to determine
the time at which to harvest to maximize the nutritional contribution of sweet peppers.

Año: 2020

Palabras claves: Bacillus, Biofertilizer, Nutraceutical, Antioxidants, Vitamin C

Referencia APA: Cisternas-Jamet, J., Salvatierra-Martínez, R., Vega-Gálvez, A., Stoll, A., Uribe, E., & Goñi, M. (2020). Biochemical composition as a function of fruit maturity stage of bell pepper (Capsicum annum) inoculated with Bacillus amyloliquefaciens. Scientia Horticulturae, 263, 109107. doi: 10.1016/j.scienta.2019.109107

“Citizen Science Among All” Participatory Bird Monitoring of the Coastal Wetland of the Limarí River, Chile

Autores:

Nuñez-Farias, P., Velásquez-Contreras, S., Ríos-Carmona, V., Velásquez-Contreras, J., Velásquez-Contreras, M., Rojas-Rojas, J., & Riveros-Flores, B.

Resumen:

We are a group of young people interested in the protection of the coastal wetland of the Limarí River, located south of the Atacama Desert in Chile. Since 2016, we have conducted participatory monitoring to analyze the [End Page E3] diversity of wetland birds in the Fray Jorge Biosphere Reserve. The reserve is a habitat for migratory and resident birds of national and international importance. However, this wetland faces constant anthropogenic threats, such as garbage accumulation, vehicle traffic, hunting of native fauna, among other problems. Citizen science has been our tool of choice to generate relevant information about this natural ecosystem, to enjoy and protect the wetland, to co-create strategies to improve human practices in the natural environment. Together with birdwatchers, scientists and naturalists, we have generated a list of 70 bird species for the site, quantifying the seasonal changes in richness and abundance of wetland species. But, the best results have been for each of the team members: during each visit to the wetland, we make new friends, we have a lot of fun, and we learn together about nature. This experience has empowered us to communicate with the inhabitants of the locality and to the state agencies why we should all take care of our coastal wetlands.

The above describes our local treasure, and we want to share the characteristics, acquired learning, and a little of the magic that makes this group unique in order to inform protagonists, students, regulators, and followers of citizen science.

Año: 2019

Palabras claves:

Referencia APA: Nuñez-Farias, P., Velásquez-Contreras, S., Ríos-Carmona, V., Velásquez-Contreras, J., Velásquez-Contreras, M., Rojas-Rojas, J., & Riveros-Flores, B. (2019). “Citizen Science Among All” Participatory Bird Monitoring of the Coastal Wetland of the Limarí River, Chile. Narrative Inquiry In Bioethics, 9(1), E3-E8. doi: 10.1353/nib.2019.0023

Antarctic Extremophiles: Biotechnological Alternative to Crop Productivity in Saline Soils

Autores:

Acuña-Rodríguez, I., Hansen, H., Gallardo-Cerda, J., Atala, C., & Molina-Montenegro, M.

Resumen:

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.

Año: 2019

Palabras claves: Extremophiles, Antarctica, functional symbiosis, crops, food security, salt tolerance

Referencia APA: Acuña-Rodríguez, I., Hansen, H., Gallardo-Cerda, J., Atala, C., & Molina-Montenegro, M. (2019). Antarctic Extremophiles: Biotechnological Alternative to Crop Productivity in Saline Soils. Frontiers In Bioengineering And Biotechnology, 7. doi: 10.3389/fbioe.2019.00022

Nutrient exchange in arbuscular mycorrhizal symbiosis from a thermodynamic point of view

Autores:

Dreyer, I., Spitz, O., Kanonenberg, K., Montag, K., Handrich, M., & Ahmad, S., Schott‐Verdugo, S., Navarro‐Retamal, C., Rubio‐Meléndez, M.E., Gomez‐Porras, J.L., Riedelsberger, J., Molina‐Montenegro, M.A., Succurro, A., Zuccaro, A., Gould, S.V., Bauer, P., Schmitt, L., Gohlke, H.

Resumen:

To obtain insights into the dynamics of nutrient exchange in arbuscular mycorrhizal (AM) symbiosis, we modelled mathematically the two‐membrane system at the plant–fungus interface and simulated its dynamics.

In computational cell biology experiments, the full range of nutrient transport pathways was tested for their ability to exchange phosphorus (P)/carbon (C)/nitrogen (N) sources.

As a result, we obtained a thermodynamically justified, independent and comprehensive model of the dynamics of the nutrient exchange at the plant–fungus contact zone. The predicted optimal transporter network coincides with the transporter set independently confirmed in wet‐laboratory experiments previously, indicating that all essential transporter types have been discovered.

The thermodynamic analyses suggest that phosphate is released from the fungus via proton‐coupled phosphate transporters rather than anion channels. Optimal transport pathways, such as cation channels or proton‐coupled symporters, shuttle nutrients together with a positive charge across the membranes. Only in exceptional cases does electroneutral transport via diffusion facilitators appear to be plausible. The thermodynamic models presented here can be generalized and adapted to other forms of mycorrhiza and open the door for future studies combining wet‐laboratory experiments with computational simulations to obtain a deeper understanding of the investigated phenomena.

Año: 2018

Palabras claves: computational cell biology, modelling, nutrient transport, plant biophysics, plant–fungus interaction

Referencia APA: Dreyer, I., Spitz, O., Kanonenberg, K., Montag, K., Handrich, M., & Ahmad, S., Schott‐Verdugo, S., Navarro‐Retamal, C., Rubio‐Meléndez, M.E., Gomez‐Porras, J.L., Riedelsberger, J., Molina‐Montenegro, M.A., Succurro, A., Zuccaro, A., Gould, S.V., Bauer, P., Schmitt, L., Gohlke, H. (2019). Nutrient exchange in arbuscular mycorrhizal symbiosis from a thermodynamic point of view. New Phytologist, 222(2), 1043-1053. doi: 10.1111/nph.15646

Coastal biophysical processes and the biogeography of rocky intertidal species along the south-eastern Pacific

Autores:

Lara, C., Saldías, G., Cazelles, B., Rivadeneira, M., Haye, P., & Broitman, B.

Resumen:

Aim
We assess the spatial distribution of a suite of coastal biophysical characteristics and how their variability is related to the distribution and geographic range of a diverse assemblage of coastal benthic species with different larval dispersal strategies.

Location
South‐eastern Pacific (SEP) coast between 18°20′S and 42°35′S.

Methods
Biophysical variability was assessed using chlorophyll‐a concentration, sea surface temperature and the signal of turbid river plumes derived from MODIS onboard the Aqua satellite. We established the dominant spatial components using wavelet and coherence analysis, and evaluated the biogeographic structure of 51 rocky intertidal species sampled over ~2,600 km along the SEP using multivariate classification and regression trees.

Results
Biogeographic breaks detected here were consistent with recent biogeographic classification schemes. Distribution breakpoints for species with lecithotrophic larvae clustered around 30°S. We observed a previously unreported break in the distribution of species with planktotrophic larval dispersal strategies around 35°S. These breaks are related to coherence in the spatial structure of sea surface temperature, chlorophyll‐a and river outflow over different temporal scales. Regions with similar biophysical characteristics, and the breaks the separate them, are in striking agreement with the biogeographic patterns revealed by the multivariate classification trees.

Main conclusions
Our results reconcile patterns of biogeographic structure reported for other groups of species along the SEP coast. We suggest that river outflow, a poorly studied coastal environmental forcing, may play an important role in determining the geographic distribution of rocky shore species, probably through its effects on larval dispersal patterns.

Año: 2018

Palabras claves: biogeographic provinces, larval dispersal, MODIS, multiscale coherence, river outflows, rocky shore invertebrates

Referencia APA: Lara, C., Saldías, G., Cazelles, B., Rivadeneira, M., Haye, P., & Broitman, B. (2019). Coastal biophysical processes and the biogeography of rocky intertidal species along the south-eastern Pacific. Journal Of Biogeography, 46(2), 420-431. doi: 10.1111/jbi.13492

Asymmetric competitive effects during species range expansion: An experimental assessment of interaction strength between “equivalent” grazer species in their range overlap

Autores:

Aguilera, M., Valdivia, N., Jenkins, S., Navarrete, S., & Broitman, B.

Resumen:

Biotic interactions are central to the development of theory and concepts in community ecology; experimental evidence has shown their strong effects on patterns of population and community organization and dynamics over local spatial scales. The role of competition in determining range limits and preventing invasions at biogeographic scales is more controversial, partly because of the complexity of processes involved in species colonization of novel habitats and the difficulties in performing appropriate manipulations and controls.

We examined experimentally whether competition is likely to affect poleward range expansion hindering or facilitating the establishment of the limpet Scurria viridula along the south‐eastern Pacific rocky shore (30°S, Chile) in the region occupied by the congeneric S. zebrina. We also assessed whether competition with the “invader” or range‐expanding species could reduce individual performance of the “native” S. zebrina and depress local populations.

Geographic field surveys were conducted to characterize the abundance and identity of limpets along the south‐eastern Pacific coast from 18°S to 41°S, and the micro‐scale (few cm) spatial distribution across the range overlap of the two species. Field‐based competition experiments were conducted at the southern leading edge of the range of S. viridula (33°S) and at the northern limit of S. zebrina (30°S).

Field surveys showed poleward range expansion of S. viridula of ca. 210 km since year 2000, with an expansion rate of 13.1 km/year. No range shift was detected for S. zebrina. The resident S. zebrina had significant negative effects on the growth rate of the invading juvenile S. viridula, while no effect of the latter was found on S. zebrina. Spatial segregation between species was found at the scale of cms.

Our results provide novel evidence of an asymmetric competitive effect of a resident species on an invader, which may hamper further range expansion. No negative effect of the invader on the resident species was detected. This study highlights the complexities of evaluating the role of species interactions in setting range limits of species, but showed how interspecific competition might slow the advance of an invader by reducing individual performance and overall population size at the advancing front.

Año: 2018

Palabras claves: field experiments, grazers, Pacific Ocean, range overlap, range shift, transitional zone

Referencia APA: Aguilera, M., Valdivia, N., Jenkins, S., Navarrete, S., & Broitman, B. (2018). Asymmetric competitive effects during species range expansion: An experimental assessment of interaction strength between “equivalent” grazer species in their range overlap. Journal Of Animal Ecology, 88(2), 277-289. doi: 10.1111/1365-2656.12917