Publicaciones

Scales of predator detection behavior and escape in Fissurella limbata: A field and laboratory assessment

Manzur, T., Gonzalez-Mendez, A. and Broitman, B.

The consumptive effects of predators are widely acknowledged, but predation can also impact prey populations through non‐consumptive effects (NCEs) such as costly antipredator behavioral responses. The magnitude of antipredator behavioral responses by prey is determined by an assessment of risk using sensory cues, which in turn is modulated by the environmental context. We studied the detection behavior and escape response of the keyhole limpet Fissurella limbata from the predatory sea star Heliaster helianthus. Through laboratory and field experimental trials, we quantified the distance and time of predator detection behavior by the prey, and measured their active escape responses when elicited. We found that predator detection by the limpet was chiefly mediated by distance, with experimental individuals capable of detecting predator presence effectively up to distances of at least 50 cm in the field and 70 cm under laboratory conditions. Our results indicate that this prey species is able to evaluate the proximity of its predator and use it as an indication of predation risk; therefore, predator–prey distance appears to be a primary predictor of the magnitude of the antipredator response. Given the tight relationship between predator distance and prey movement and the important role herbivores can play, particularly in this ecosystem, we expect that NCEs will cascade to the patterns of abundance and composition of rocky shore communities through changes in prey foraging behavior under risk.

Año: 2018

Palabras claves: antipredator behavior, escape, non‐consumptive effects, predator detection behavior, predator–prey interactions, rocky inter‐tidal, spatial scale

Low prevalence of microplastic contamination in planktivorous fish species from southeast Pacific Ocean

Ory, N., Chagnon, C., Felix, F., Fernández, C., Ferreira, J., Gallardo, C., Garcés Ordóñez, O., Henostroza, A., Laaz, E., Mizraji, R., Mojica, H., Murillo Haro, V., Ossa Medina, L., Preciado, M., Sobral, P., Urbina, M. and Thiel, M.

The gut contents of 292 planktivorous fish, from four families (Atherinopsidae, Clupeidae, Engraulidae and Scombridae) and seven species, captured along the coast of the southeast Pacific, were examined for microplastic contamination. Only a small fraction of all studied fish (2.1%; 6 individuals) contained microplastic particles in their digestive tract. Microplastics found were degraded hard fragments and threads, ranging from 1.1 to 4.9 (3.8 ± SD 2.4) mm in length, and of various colours, which suggests that the planktivorous fish species examined herein did not capture microplastics on the basis of their colour. The low prevalence of microplastic contamination in planktivorous fishes found in this study suggests that the risk of accidental ingestion by these species might be limited in the coastal upwelled waters of the southeast Pacific, perhaps due to small human population and highly dynamic oceanographic processes.

Año: 2018

Palabras claves: Microplastic contamination, Planktivorous fish, Southeast Pacific Ocean, Upwelling systems, Humboldt Current System

No reef-associated gradient in the infaunal communities of Rapa Nui (Easter Island) – Are oceanic waves more important than reef predators?

Gusmao, J., Lee, M., MacDonald, I., Ory, N., Sellanes, J., Watling, L. and Thiel, M.

Reef-associated predators are thought to influence the distribution of invertebrates of surrounding sediment habitats. In this study, we analyzed the predation pressure and the distributional patterns of macro- and meiofaunal assemblages in soft sediments surrounding two coral reef sites at Rapa Nui (Easter Island), in the central South Pacific. We tested the hypothesis that reef-associated predators negatively affect sediment-dwelling invertebrates, causing macro- and meiofauna to be less abundant and diverse in soft sediments near the reefs. As expected, predation intensity was greater nearer the reef than farther away, but macro- and meiofaunal assemblages did not differ significantly with distance from the reef. Taxon richness of macro- and meiofaunal assemblages were similar irrespective of distance from the reef. Only meiofauna showed significant variation in total abundance with distance from the reef, but this trend was not consistent between the two study sites. No gradient in sediment texture was observed with distance from the reef. Underwater video recordings at one study site also revealed that local hydrodynamics cause frequent disturbance and resuspension of the upper sediment layers. Our results suggest that soft-sediment assemblages are constantly reshuffled by oceanic waves, thereby blurring the potential effects of predation on invertebrate assemblages closer to the reef.

Año: 2018

Palabras claves: Easter islandSoft-bottom assemblagesMacrofaunaMeiofaunaInfaunal halosReef fishesPredation

Spatio-temporal variation of anthropogenic marine debris on Chilean beaches

Hidalgo-Ruz, V., Honorato-Zimmer, D., Gatta-Rosemary, M., Nuñez, P., Hinojosa, I. and Thiel, M.

We examined the hypothesis that in an emerging economy such as Chile the abundances of Anthropogenic Marine Debris (AMD) on beaches are increasing over time. The citizen science program Científicos de la Basura (“Litter Scientists”) conducted three national surveys (2008, 2012 and 2016) to determine AMD composition, abundance, spatial patterns and temporal trends. AMD was found on all beaches along the entire Chilean coast. Highest percentages of AMD in all surveys were plastics and cigarette butts, which can be attributed to local sources (i.e. beach users). The Antofagasta region in northern Chile had the highest abundance of AMD compared with all other zones. Higher abundances of AMD were found at the upper stations from almost all zones. No significant tendency of increasing or decreasing AMD densities was observed during the 8 years covered by our study, which suggests that economic development alone cannot explain temporal trends in AMD densities.

Año: 2018

Palabras claves: Anthropogenic marine debrisBeachesCitizen scienceTemporal trendsAntofagastaEconomic development

Metagenomic exploration of soils microbial communities associated to Antarctic vascular plants

Molina-Montenegro, M., Ballesteros, G., Castro-Nallar, E., Meneses, C., Torres-Díaz, C. and Gallardo-Cerda, J.

Antarctica is one of the most stressful ecosystems worldwide with few vascular plants,which are limited by abiotic conditions. Here, plants such as Deschampsia antarctica (Da)could generate more suitable micro-environmental conditions for the establishment ofother plants as Colobanthus quitensis (Cq). Although, plant-plant interaction is known todetermine the plant performance, little is known about how microorganisms mightmodulate the ability of plants to cope with stressful environmental conditions. Severalreports have focused on the possible ecological roles of microorganism with vascularplants, but if the rizospheric microorganisms can modulate the positive interactions amongvascular Antarctic plants has been seldom assessed. In this study, we compared therhizosphere microbiomes associated with Cq, either growing alone or associated with Da,using a shotgun metagenomic DNA sequencing approach and using eggNOG forcomparative and functional metagenomics. Overall, results show higher diversity oftaxonomic and functional groups in rhizospheric soil from Cq+Da than Cq. On the otherhand, functional annotation shows that microorganisms from rhizospheric soil from Cq+Dahave a significantly higher representation of genes associated to metabolic functionsrelated with environmental stress tolerance than Cq soils. Additional research is needed toexplore both the biological impact of these higher activities in terms of gene transfer onplant performance and in turn help to explain the still unsolved enigma about the strategydeployed by Cq to inhabit and cope with harsh conditions prevailing in Antarctic.

Año: 2018

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Temporal Variability of MODIS Phenological Indices in the Temperate Rainforest of Northern Patagonia

Lara, C., Saldías, G., Paredes, A., Cazelles, B. and Broitman, B.

Western Patagonia harbors unique and sparsely studied terrestrial ecosystems that are threatened by land use changes and exposure to basin-scale climatic variability. We assessed the performance of two satellite vegetation indices derived from MODIS–Terra, EVI (Enhanced Vegetation Index) and NDVI (Normalized Difference Vegetation Index), over the northern and southern sectors of the Chiloé Island System (CIS) to advance our understanding of vegetation dynamics in the region. Then we examined their time-varying relationships with two climatic indices indicative of tropical and extratropical influence, the ENSO (El Niño–Southern Oscillation) and the Antarctic Oscillation (AAO) index, respectively. The 17-year time series showed that only EVI captured the seasonal pattern characteristic of temperate regions, with low (high) phenological activity during Autumn-Winter (Spring–Summer). NDVI saturated during the season of high productivity and failed to capture the seasonal cycle. Temporal patterns in productivity showed a weakened seasonal cycle during the past decade, particularly over the northern sector. We observed a non-stationary association between EVI and both climatic indices. Significant co-variation between EVI and the Niño–Southern Oscillation index in the annual band persisted from 2001 until 2008–2009; annual coherence with AAO prevailed from 2013 onwards and the 2009–2012 period was characterized by coherence between EVI and both climate indices over longer temporal scales. Our results suggest that the influence of large-scale climatic variability on local weather patterns drives phenological responses in the northern and southern regions of the CIS. The imprint of climatic variability on patterns of primary production across the CIS may be underpinned by spatial differences in the anthropogenic modification of this ecosystem, as the northern sector is strongly modified by forestry and agriculture. We highlight the need for field validation of satellite indices around areas of high biomass and high endemism, located in the southern sector of the island, in order to enhance the utility of satellite vegetation indices in the conservation and management of austral ecosystems.

Año: 2018

Palabras claves: MODIS; primary productivity; climatic variability; vegetation index; wavelet coherence

Asymmetric connectivity of the lobster Panulirus pascuensis in remote islands of the southern Pacific: importance for its management and conservation

Meerhoff, E., Yannicelli, B., Dewitte, B., Díaz-Cabrera, E., Vega-Retter, C., Ramos, M., Bravo, L., Concha, E., Hernández-Vaca, F. and Véliz, D.

Understanding patterns of marine connectivity in oceanic islands is a fundamental element for conservation and management of fished species. In the present study, the level of connectivity of the endemic lobster Panulirus pascuensis Reed, 1954 from remote islands in the southern Pacific Ocean was estimated, focusing on the Motu Motiro Hiva Marine Park (MMH), considered here as a source of recruits to Easter Island. The connectivity of adult lobster populations between Eastern Island (EI) and Salas y Gómez Island (SG), in the center of MMH, was studied by quantifying the reciprocal migration rates using variability of microsatellite loci and a biophysical individual-based model of larval transport based on the outputs of a regional high-resolution oceanic model. Considering a system composed only of adult populations located in both islands, the genetic analysis showed that 3% of the adults from EI came from SG; however, only 0.02% in the opposite direction. Neglecting the effect of other islands (e.g., Pitcairn Island located at 2000 km west of EI), the self-recruitment was estimated at 97% in EI and 99.8% in SG. The results of the Lagrangian analysis of the oceanic model simulations are consistent with the concept of asymmetric connectivity, although there is appreciable variation in recruitment among years. Both genetic and oceanographic approaches revealed large variance in connectivity from SG to EI. The asymmetric connectivity from SG to EI emphasizes the importance of the MMH Marine Park for lobster conservation in SG, and that it also supports recruitment of P. pascuensis to EI.

Año: 2018

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Breeding of the south american tern (Sterna hirundinacea) on anchored boats in Coquimbo, northern Chile

Portflitt-Toro, M., Miranda-Urbina, D., Fernández, C., Luna, N., Plaza, P., Serratosa, J., Thiel, M., Luna-Jorquera, G.

Abstract · We report the breeding attempt of South American Terns (Sterna hirundinacea) on three boats in
Coquimbo, northern Chile. The first breeding attempt was reported in winter 2011 where at least one chick fledged. From April to June 2015, all nests on the boats were monitored. We recorded eggs and chicks during May and early June. However, towards the end of June, no eggs or chicks were recorded in the nests, and a Chimango Caracara (Phalcoboenus chimango) was observed preying on chicks in one nest. In April and May 2017, breeding attempts on boats were also monitored and nests with eggs and one chick were recorded. However, at the end of May all nests were empty. This unusual nesting site for South American Terns is apparently regularly used in the area despite its virtually null breeding success.

Resumen · Reproducción del Gaviotín Sudamericano (Sterna hirundinacea) en botes anclados en Coquimbo, norte de Chile

Reportamos el intento de reproducción del Gaviotín Sudamericano (Sterna hirundinacea) sobre tres botes en Coquimbo, norte de Chile. Un primer intento de reproducción para esta zona se registró en invierno de 2011, donde al menos un pollo dejó un nido como volantón. Entre Abril y Junio de 2015 monitoreamos los nidos en los botes de manera más intensiva. Registramos huevos y pollos durante Mayo y principios de Junio. Sin embargo, a finales de Junio, no registramos huevos en los nidos y observamos un Tiuque (Phalcoboenus chimango) depredar sobre los pollos. En Abril y Mayo de 2017, monitoreamos otros intentos de reproducción y registramos un pollo y nidos con huevos. Sin embargo, a finales de Mayo, esos nidos estaban vacíos. Este inusual sitio de nidificación parece ser utilizado de forma recurrente por el Gaviotín Sudamericano, a pesar del aparente casi nulo éxito reproductivo.

Año: 2018

Palabras claves: Anchored boats, Chile, Nesting, Predation, South American Tern

Phenotypic plasticity at the edge: Contrasting population‐level responses at the overlap of the leading and rear edges of the geographical distribution of two Scurria limpets

Broitman, B., Aguilera, M., Lagos, N. and Lardies, M.

Aim
To examine the role of ocean temperature and chemistry as drivers of interpopulation differences in multiple phenotypic traits between rear and leading edge populations of two species of limpet.

Location
The coast of north‐central Chile, western South America.

Taxon
Mollusca, Gastropoda (Lottidae).

Methods
We used field and laboratory experiments to study the ecology and physiology of individuals from populations located at the overlap of the rear and leading edges of their respective geographical distributions. At the same time, we characterized local environmental regimes, measuring seawater physical and chemical properties.

Results
Towards the edge of their range, individuals from the leading edge species gradually reduced their shell length, metabolic rate and thermal response capacity, and increased carbonate content in their shells. Individuals of the rear edge species showed dissimilar responses between sites. Contrasting behavioural responses to experimental heating reconciled observations of an unintuitive higher maximal critical temperature and a smaller thermal safety margin for individuals of the rear edge populations. Physical–chemical characterization of seawater properties at the site located on the core of the upwelling centre showed extreme environmental conditions, with low oxygen concentration, high pCO2 and the episodic presence of corrosive seawater. These challenging environmental conditions were reflected in reduced growth for both species.

Main conclusions
We found different spatial patterns of phenotypic plasticity in two sister species around the leading and trailing edges of their distributions. Our results provide evidence that environmental conditions around large upwelling centres can maintain biogeographical breaks through metabolic constraints on the performance of calcifying organisms. Thus, local changes in seawater chemistry associated with coastal upwelling circulation emerge as a previously overlooked driver of marine range edges.

Año: 2018

Palabras claves: biogeographical break, calcification, limpet, Scurria, SE Pacific, thermal physiology, upwelling