Publicaciones

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

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

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

Isolation and cross-amplification of the first set of polymorphic microsatellite markers of two high-Andean cushion plants

Acuña-Rodríguez, I., Gouin, N., Cifuentes-Lisboa, L., & Squeo, F.

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 in wild 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.

Año: 2018

Palabras claves: Cushion plants, High-Andes, Microsatellite markers, Azorella madreporica, Laretia acaulis.

The 2017 coastal El Niño

Takahashi, K.; Aliaga-Nestares, V.; Avalos, G.; Bouchon, M.; Castro, A.; Cruzado, L.; Dewitte, B.; Gutiérrez, D.; Lavado-Casimiro, W.; Marengo, J.; Martínez, A. G.; Mosquera-Vásquez, K.; Quispe, N.

The original concept of El Niño consisted of anomalously high sea surface temperature and heavy rainfall along the arid northern coast of Peru (Carranza 1891; Carrillo 1893). The concept evolved into the El Niño–Southern Oscillation (ENSO; Bjerknes 1969), although the original El Niño and the Southern Oscillation do not necessarily have the same variability (Deser and Wallace 1987), and the strong El Niño episode in early 1925 coincided with cold-to-neutral ENSO conditions (Takahashi and Martínez 2017). To distinguish the near-coastal El Niño from the warm ENSO phase, Peru operationally defines the “coastal El Niño” based on the seasonal Niño 1+2 SST anomaly (ENFEN 2012; L’Heureux et al. 2017). While recent attention has been
brought to the concept of ENSO diversity (e.g., “central Pacific” vs “eastern Pacific” events; Capotondi et al. 2015), the coastal El Niño represents another facet of ENSO that requires further study in terms of its mechanisms and predictability.

Año: 2018

Palabras claves:

Extreme El Niño Events

Dewitte, B., & Takahashi, K.

Every few years the tropical Pacific warms abnormally in association with a relaxation of the trade winds, a phenomenon known as the El Niño–Southern Oscillation (ENSO) that represents the strongest fluctuation of the global climate system. Although the contemporary observational record indicates that all El Niño events are not alike, differing in amplitude, warming pattern, and teleconnection, there is a class of events that stands out in terms of the societal and economical impacts: the extreme El Niño events that have occurred every 15–20 years. In this chapter, we propose an overview of the state of knowledge and of some current lines of research dedicated to extreme El Niño events. Building on the recently proposed concept of ENSO diversity, we further synthesize our current understanding of the nonlinear dynamics of this class of events and their expected evolution in a warmer climate and highlight some challenges in ENSO research.

Año: 2018

Palabras claves: El Niño, ENSO diversity, External forcing, Global warming, Teleconnection.

Is Precipitation a Good Metric for Model Performance?

Tapiador, F., Roca, R., Del Genio, A., Dewitte, B., Petersen, W., & Zhang, F.

Precipitation has often been used to gauge the performances of numerical weather and climate models, sometimes together with other variables such as temperature, humidity, geopotential, and clouds. Precipitation, however, is singular in that it can present a high spatial variability and probably the sharpest gradients among all meteorological fields. Moreover, its quantitative measurement is plagued with difficulties, and there are even notable differences among different reference datasets. Several additional issues sometimes lead to questions about its usefulness in model validation. This essay discusses the use of precipitation for model verification and validation and the crucial role of highly precise and reliable satellite estimates, such as those from NASA’s Global Precipitation Mission Core Observatory.

Año: 2018

Palabras claves:

Chapter 29 – Chile: Environmental Status and Future Perspectives

Aguilera, M., Aburto, J., Bravo, L., Broitman, B., García, R., & Gaymer, C., Gelcich, S., López, B.A., Montecino, V., Pauchard, A., Ramos, M., Rutllant, J.A., Sáez, C.A., Valdivia, N., Thiel, M.

The coast of mainland Chile extends from 18°S to about 56°S, and is about 4200 km long. In the north, the coast is characterized by continuous, regular, and wave-exposed shores, while to south of 40°S it is highly fragmented, with extensive fjords and small archipelagos with many wave-protected zones. The Humboldt Current System (HCS) determines oceanographic and ecological processes in the northern part, with persistent upwelling fronts and episodic “El Niño” events. In the southern part the southward-flowing Magellan Current is important. Coastal upwelling along the HCS sustains a diverse pelagic and benthic food web structure. Rocky coastal habitats are dominated by large kelp forests and filter-feeding species like reef-forming mussels and tunicates.

The main coastal habitats along the coast of Chile are rocky shores, sandy beaches, coastal wetlands, and dunes. The main populated zones are concentrated between 33°S to 35°S in central Chile, with economically important trading ports. Sewage discharges from large cities have the potential to increase nutrients levels in nearshore habitats causing localized eutrophication. Mining activities in northern Chile contaminate coastal waters, while in the south intensive aquaculture affects the fjord ecosystem. Also, subsistence harvesting (of kelps, molluscs, fish) is dramatically reducing the abundance of top consumers or habitat-forming species.

The diverse and productive coastal marine ecosystems are used by different socioeconomic activities and exposed to interventions which are potentially harmful. Ecosystem services should be managed, and necessary interventions carefully planned. Achieving sustainable use of natural marine resources and coastal ecosystem integrity is challenging, and a basic understanding of ecosystem responses to direct human impacts and global climate change require better monitoring strategies. The establishment of a marine reserve “Humboldt Current System” would be a major step toward this goal.

Año: 2019

Palabras claves: Continental Chile, Climate, Coastal Ecology, Human interventions, Humboldt Current System, Oceanography, Southeastern Pacific.

Cross-cultural invariances in the architecture of shame

Sznycer, D., Xygalatas, D., Agey, E., Alami, S., An, X., & Ananyeva, K., Atkinson, Q.D., Broitman, B.R., Conte, T.J., Flores, C., Fukushima, S., Hitokoto, H., Kharitonov, A.N., Onyishi, C.N., Onyishi, I.E., Romero, P.P., Schrock, J.M., Snodgrass, J., Sugiyama, L.S., Takemura, K., Townsend, C., Zhuang, , J-Y., Athena Aktipis, C., Cronk, L., Cosmides, L., Tooby, J.

Human foragers are obligately group-living, and their high dependence on mutual aid is believed to have characterized our species’ social evolution. It was therefore a central adaptive problem for our ancestors to avoid damaging the willingness of other group members to render them assistance. Cognitively, this requires a predictive map of the degree to which others would devalue the individual based on each of various possible acts. With such a map, an individual can avoid socially costly behaviors by anticipating how much audience devaluation a potential action (e.g., stealing) would cause and weigh this against the action’s direct payoff (e.g., acquiring). The shame system manifests all of the functional properties required to solve this adaptive problem, with the aversive intensity of shame encoding the social cost. Previous data from three Western(ized) societies indicated that the shame evoked when the individual anticipates committing various acts closely tracks the magnitude of devaluation expressed by audiences in response to those acts. Here we report data supporting the broader claim that shame is a basic part of human biology. We conducted an experiment among 899 participants in 15 small-scale communities scattered around the world. Despite widely varying languages, cultures, and subsistence modes, shame in each community closely tracked the devaluation of local audiences (mean r = +0.84). The fact that the same pattern is encountered in such mutually remote communities suggests that shame’s match to audience devaluation is a design feature crafted by selection and not a product of cultural contact or convergent cultural evolution.

Año: 2018

Palabras claves: emotion, cognition, culture, cooperation, evolutionary psychology.

Pedogenic and microbial interrelations to regional climate and local topography: New insights from a climate gradient (arid to humid) along the Coastal Cordillera of Chile

Bernhard, N., Moskwa, L., Schmidt, K., Oeser, R., Aburto, F., & Bader, M., Baumann, K., von Blanckenburg, F., Boy, J., van den Brink, L., Brucker, E., Büdel, B., Canessa, R., Dippold, M.A., Ehlers, T.A., Fuentes, J.P., Godoy, R., Jung, P., Karsten, U., Köster, M., Kuzyakov, Y., Leinweber, P., Neidhardt, H., Matus, F., Mueller, C.W., Oelmann, Y., Oses, R., Osses, P., Paulino, L., Samolov, E., Schaller, M., Schmid, M., Spielvogel, S., Spohn, M., Stock, S., Stroncik, N., Tielbörger, K., Übernickel, K., Scholten, T., Seguel, O., Wagner, D., Kühn, P.

The effects of climate and topography on soil physico-chemical and microbial parameters were studied along an extensive latitudinal climate gradient in the Coastal Cordillera of Chile (26°–38°S). The study sites encompass arid (Pan de Azúcar), semiarid (Santa Gracia), mediterranean (La Campana) and humid (Nahuelbuta) climates and vegetation, ranging from arid desert, dominated by biological soil crusts (biocrusts), semiarid shrubland and mediterranean sclerophyllous forest, where biocrusts are present but do have a seasonal pattern to temperate-mixed forest, where biocrusts only occur as an early pioneering development stage after disturbance. All soils originate from granitic parent materials and show very strong differences in pedogenesis intensity and soil depth.

Most of the investigated physical, chemical and microbiological soil properties showed distinct trends along the climate gradient. Further, abrupt changes between the arid northernmost study site and the other semi-arid to humid sites can be shown, which indicate non-linearity and thresholds along the climate gradient. Clay and total organic carbon contents (TOC) as well as Ah horizons and solum depths increased from arid to humid climates, whereas bulk density (BD), pH values and base saturation (BS) decreased. These properties demonstrate the accumulation of organic matter, clay formation and element leaching as key-pedogenic processes with increasing humidity. However, the soils in the northern arid climate do not follow this overall latitudinal trend, because texture and BD are largely controlled by aeolian input of dust and sea salts spray followed by the formation of secondary evaporate minerals. Total soil DNA concentrations and TOC increased from arid to humid sites, while areal coverage by biocrusts exhibited an opposite trend. Relative bacterial and archaeal abundances were lower in the arid site, but for the other sites the local variability exceeds the variability along the climate gradient. Differences in soil properties between topographic positions were most pronounced at the study sites with the mediterranean and humid climate, whereas microbial abundances were independent on topography across all study sites. In general, the regional climate is the strongest controlling factor for pedogenesis and microbial parameters in soils developed from the same parent material. Topographic position along individual slopes of limited length augmented this effect only under humid conditions, where water erosion likely relocated particles and elements downward. The change from alkaline to neutral soil pH between the arid and the semi-arid site coincided with qualitative differences in soil formation as well as microbial habitats. This also reflects non-linear relationships of pedogenic and microbial processes in soils depending on climate with a sharp threshold between arid and semi-arid conditions. Therefore, the soils on the transition between arid and semi-arid conditions are especially sensitive and may be well used as indicators of long and medium-term climate changes. Concluding, the unique latitudinal precipitation gradient in the Coastal Cordillera of Chile is predestined to investigate the effects of the main soil forming factor – climate – on pedogenic processes.

Año: 2018

Palabras claves: Climate, Topography, Soil texture, Total organic carbon, Carbon isotope ratio (δ13CTOC), Microbial abundance.

Microplastic: What Are the Solutions?

Eriksen, M., Thiel, M., Prindiville, M., & Kiessling, T.

The plastic that pollutes our waterways and the ocean gyres is a symptom of upstream material mismanagement, resulting in its ubiquity throughout the biosphere in both aquatic and terrestrial environments. While environmental contamination is widespread, there are several reasonable intervention points present as the material flows through society and the environment, from initial production to deep-sea microplastic sedimentation. Plastic passes through the hands of many stakeholders, with responsibility for environmental contamination owned, shared, or rejected by plastic producers, product/packaging manufacturers, government, consumers, and waste handlers.

The contemporary debate about solutions, in a broad sense, largely contrasts the circular economy with the current linear economic model. While there is a wide agreement that improved waste recovery is essential, how that waste is managed is a different story. The subjective positions of stakeholders illuminate their economic philosophy, whether it is to maintain demand for new plastic by incinerating postconsumer material or maintain material efficacy through recycling, regulated design, and producer responsibility; many proposed solutions fall under linear or circular economic models. Recent efforts to bring often unheard stakeholders to the table, including waste pickers in developing countries, have shed new light on the life cycle of plastic in a social justice context, in response to the growing economic and human health concerns.

In this chapter we discuss the main solutions, stakeholder costs, and benefits. We emphasize the role of the “honest broker” in science, to present the best analysis possible to create the most viable solutions to plastic pollution for public and private leadership to utilize.

Año: 2017

Palabras claves: Extended producer responsibility, Marine debris solutions, Microplastic, Plastic marine pollution, Recycling, Reuse.