UCN-CEAZA
Major consequences of minor damage: impacts of small grazers on fast-growing kelps.
Poore, A., Gutow, L., F. Pantoja, J., Tala, F., Jofré Madariaga, D., & Thiel, M.
Damage by small herbivores can have disproportionately large effects on the fitness of individual plants if damage is concentrated on valuable tissues or on select individuals within a population. In marine systems, the impact of tissue loss on the growth rates of habitat-forming algae is poorly understood. We quantified the grazing damage by an isopod Amphoroidea typa on two species of large kelps, Lessonia spicata and Macrocystis pyrifera, in temperate Chile to test whether non-lethal grazing damage could reduce kelp growth rates and photosynthetic efficiency. For L. spicata, grazing damage was widespread in the field, unevenly distributed on several spatial scales (among individuals and among tissue types) and negatively correlated with blade growth rates. In field experiments, feeding by A. typa reduced the concentration of photosynthetic pigments and led to large reductions (~80 %) in blade growth rates despite limited loss of kelp biomass (0.5 % per day). For M. pyrifera, rates of damage in the field were lower and high densities of grazers were unable to reduce growth rates in field experiments. These results demonstrate that even low per capita grazing rates can result in large reductions in the growth of a kelp, due the spatial clustering of herbivores in the field and the selective removal of photosynthetically active tissues. The impacts of small herbivores on plant performance are thus not easily predicted from consumption rates or abundance in the field, and vary with plant species due to variation in their ability to compensate for damage.
Año: 2014
Palabras claves: Grazing, Herbivory, Isopods, Lessonia, Mesograzers, Macroalgae, Macrocystis, Plant–herbivore interactions.
Referencia APA: Poore, A., Gutow, L., F. Pantoja, J., Tala, F., Jofré Madariaga, D., & Thiel, M. (2014). Major consequences of minor damage: impacts of small grazers on fast-growing kelps. Oecologia, 174(3), 789-801.
Plastic Pollution in the World’s Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea.
Eriksen, M., Lebreton, L., Carson, H., Thiel, M., Moore, C., & Borerro, J. et al.
Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world's oceans from 24 expeditions (2007–2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N = 680) and visual survey transects of large plastic debris (N = 891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic <4.75 mm and meso- and macroplastic >4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove <4.75 mm plastic particles from the ocean surface.
Año: 2014
Palabras claves: Oceans, Density, Particle size, Pollution, Southern Hemisphere, Indian Ocean, Marine conservation, Mediterranean Sea.
Referencia APA: Eriksen, M., Lebreton, L., Carson, H., Thiel, M., Moore, C., & Borerro, J. et al. (2014). Plastic Pollution in the World's Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea. Plos ONE, 9(12), e111913.
Succession in intertidal mussel bed assemblages on different shores: species mobility matters.
Valdivia, N., Buschbaum, C., & Thiel, M.
Biogenic substrata such as epibenthic mussel aggregations are common in coastal regions worldwide and harbour diverse assemblages of sessile and mobile species. However, colonisation patterns on biogenic substrata are still not well understood. We tested whether succession develops as a linear sequence of temporal changes in the species richness and community structure of sessile and mobile assemblages associated with intertidal mussel beds of sedimentary and rocky shores in Germany and Chile, respectively. Because of their broad differences, these study sites were analysed separately to examine whether similar successional patterns occur under differing environmental conditions and species pools. At each study site, we conducted an experiment that separates the effects of successional age (deployment duration) and the time when settlement substrata are deployed (deployment timing). Colonisation dynamics differed between timings and between sessile and mobile species. In addition, timing effects were stronger at the sedimentary than at the rocky study site. For sessile organisms, for example, species richness increased steadily with successional age at both study sites, but at the sedimentary site, the magnitude of this increase varied between the different months of deployment. For mobile organisms, a high proportion of the total species pool colonised the settlement substrata within the first month of deployment at both sites. After this initial colonization peak, mobile species richness showed a minor but significant increase with successional age at both sites. We suggest that species dispersal ability at the local scale (mobility) mediates the response of species-rich assemblages to natural and anthropogenic disturbances.
Año: 2014
Palabras claves: Context-dependency, Determinism, Facilitation, Hard-bottom, Soft-bottom, Stochastic, Succession.
Referencia APA: Valdivia, N., Buschbaum, C., & Thiel, M. (2014). Succession in intertidal mussel bed assemblages on different shores: species mobility matters. Marine Ecology Progress Series, 497, 131-142
Phylogeographic Structure in Benthic Marine Invertebrates of the Southeast Pacific Coast of Chile with Differing Dispersal Potential.
Haye, P., Segovia, N., Muñoz-Herrera, N., Gálvez, F., Martínez, A., & Meynard, A. et al.
The role of dispersal potential on phylogeographic structure, evidenced by the degree of genetic structure and the presence of coincident genetic and biogeographic breaks, was evaluated in a macrogeographic comparative approach along the north-central coast of Chile, across the biogeographic transition zone at 30°S. Using 2,217 partial sequences of the mitochondrial Cytochrome Oxidase I gene of eight benthic invertebrate species along ca. 2,600 km of coast, we contrasted dispersal potential with genetic structure and determined the concordance between genetic divergence between biogeographic regions and the biogeographic transition zone at 30°S. Genetic diversity and differentiation highly differed between species with high and low dispersal potential. Dispersal potential, sometimes together with biogeographic region, was the factor that best explained the genetic structure of the eight species. The three low dispersal species, and one species assigned to the high dispersal category, had a phylogeographic discontinuity coincident with the biogeographic transition zone at 30°S. Furthermore, coalescent analyses based on the isolation-with-migration model validate that the split between biogeographic regions north and south of 30°S has a historic origin. The signatures of the historic break in high dispersers is parsimoniously explained by the homogenizing effects of gene flow that have erased the genetic signatures, if ever existed, in high dispersers. Of the four species with structure across the break, only two had significant albeit very low levels of asymmetric migration across the transition zone. Historic processes have led to the current biogeographic and phylogeographic structure of marine species with limited dispersal along the north-central coast of Chile, with a strong lasting impact in their genetic structure.
Año: 2014
Palabras claves: Phylogeography, Biogeography, Haplotypes, Population genetics, Chile (country), Gene flow, Larvae, Marine biology.
Referencia APA: Haye, P., Segovia, N., Muñoz-Herrera, N., Gálvez, F., Martínez, A., & Meynard, A. et al. (2014). Phylogeographic Structure in Benthic Marine Invertebrates of the Southeast Pacific Coast of Chile with Differing Dispersal Potential. Plos ONE, 9(2), e88613.
Impact of grazing by the sea urchin Tetrapygus niger on the kelp Lessonia trabeculata in Northern Chile.
Perreault, M., Borgeaud, I., & Gaymer, C.
The ability of sea urchins to destroy kelp forests, leaving large areas stripped of vegetation and covered by sparse calcareous algae is well known. The reduction in active predators of sea urchins combined with their broad diet makes them an important factor in the structuring of subtidal benthic marine systems. In central and northern Chile, the sea urchin Tetrapygus niger is known to reduce the spread of the subtidal kelp Lessonia trabeculata. However, its impact on the different development stages of L. trabeculata has never been quantified or compared to other possible causes of the loss of material. The objective of this study was to quantify the grazing impact of T. niger on L. trabeculata at different stages of development (recruits, juveniles and adults). An exclusion experiment was conducted to evaluate the grazing effect of T. niger on kelp recruitment within a kelp bed, and kelp transplant experiments were conducted to quantify T. niger's impact on the stipes and fronds of juvenile and adult L. trabeculata. Our results showed that under natural sea urchin densities (10 ind. m− 2), T. niger prevented the recruitment of L. trabeculata. Tetrapygus niger completely consumed juvenile plants but only attacked the stipes of adult plants. Tetrapygus niger seems to use different feeding strategies depending on the ontogeny of the plant. Lessonia trabeculata seems unable to defend itself against the impact of intensive grazing by sea urchins, which may be the primary source of mortality of recruits and juveniles of L. trabeculata. However, T. niger's impact on adult plants is limited and shared with other herbivores that graze the fronds, such as fishes and spider crabs.
Año: 2014
Palabras claves: Chile; Herbivory; Lessonia trabeculata; Rocky subtidal; Sea urchin–kelp interaction; Tetrapygus niger.
Referencia APA: Perreault, M., Borgeaud, I., & Gaymer, C. (2014). Impact of grazing by the sea urchin Tetrapygus niger on the kelp Lessonia trabeculata in Northern Chile. Journal Of Experimental Marine Biology And Ecology, 453, 22-27.
Social-Ecological Collapse: TURF Governance in the Context of Highly Variable Resources in Chile.
Aburto, J., Stotz, W., & Cundill, G.
In Chile, a Territorial User Rights for Fisheries system was developed to manage benthic fisheries. This system is referred to as Management Areas for the Exploitation of Benthic Resources. Management areas involved a shift from top-down control by governments to comanagement. We have analyzed the effects of a highly variable fishery, characterized by boom-and-bust cycles, on the governance of local institutions designed for resource management. We focused on a case study in north central Chile, in which the surf clam fishery experienced high levels of variability when the fishery was in an open access system. The management areas were established for the fishery in 1999. As a result, a set of rules for the fishery were created and enforced by fishers and local fishery authorities. Despite intense efforts on the part of all stakeholders, the fishery collapsed after three years of management area policy. This approach has been shown to be an effective management option for other species; however, for resources with boom-and-bust cycles, it is important to understand the response pattern of users confronting this spatial and temporal variability before the establishment of territorial user rights. Defining the appropriate spatial scale of the territorial rights could allow fishers to switch among different surf clam beds to maintain their livelihood and support the sustainability of local institutions for resource management.
Año: 2014
Palabras claves: Governance; management area; small-scale fishery; social-ecological; TURF.
Referencia APA: Aburto, J., Stotz, W., & Cundill, G. (2014). Social-Ecological Collapse: TURF Governance in the Context of Highly Variable Resources in Chile. Ecology And Society, 19(1).
Collaboration and knowledge networks in coastal resources management: How critical stakeholders interact for multiple-use marine protected area implementation.
Cárcamo, P., Garay-Flühmann, R., & Gaymer, C.
Recent studies have shown that social networks and their properties are key in the search for explanations for the success in the governance and management of natural resources. We investigated the structure and properties of inter-organizational social networks involved in the use and management of natural resources in a coastal marine ecosystem in northern Chile proposed as a possible marine protected area. We explored two network configurations: i) relations of collaboration and ii) relations of transfer and exchange of scientific knowledge and information useful to the management of natural resources and the decision-making process involved. Both networks showed little cohesion, with low values of centralization and density indicating a low flow of collaborative and exchange relations among different stakeholders. The knowledge network achieved greater levels of centralization than the collaboration network. National government agencies and fishermen organizations were the most powerful stakeholders in the collaboration network. National government agencies and universities were the most powerful stakeholders in the knowledge network. We found a disconnected network when analyzing the flows of collaboration and knowledge between different administrative operation levels that potentially would hamper the governance of this area. On the other hand, we identified stakeholders that would help to connect the network (bridging stakeholders). Additional analysis of stakeholders using influence-capacity matrix allowed us to identify key stakeholders for planning and implementing the new marine protected area, compare results with the network analysis, and propose network interventions. We propose combining Social Network Analysis with other methods of stakeholder analysis to produce more practical and implementable results. Our results are relevant for future interventions aimed at improving or implementing management and governance of coastal areas.
Año: 2014
Palabras claves:
Referencia APA: Cárcamo, P., Garay-Flühmann, R., & Gaymer, C. (2014). Collaboration and knowledge networks in coastal resources management: How critical stakeholders interact for multiple-use marine protected area implementation. Ocean & Coastal Management, 91, 5-16.
On the advantage of sharing a holdfast: effects of density and occurrence of kin aggregation in the kelp Lessonia berteroana.
Segovia, N., Vásquez, J., Faugeron, S., & Haye, P.
We investigated the density-dependent and genetic relatedness that regulate the occurrence of inter-individual (genet) fusion forming plurigenotypic organisms in the brown alga Lessonia berteroana. Recruitment generally occurs at high densities in the inter-tidal, allowing contact of neighbouring holdfasts as they grow and expand on the substrate. Algal density, by contrast, is regulated by the effects of herbivory and wave impact, which often lead to low holdfast density. Herein, we investigated whether the occurrence of plurigenotypic organisms and their genotypic composition (number of genotypes per plurigenotypic organism) are density dependent and affected by kin selection in the inter-tidal kelp L. berteroana. Four microsatellite loci were used to analyse DNA from 260 samples obtained from shared and non-shared holdfasts, at two sites with high and two site with low holdfast density. Analyses showed that fusions forming plurigenotypic organisms are extremely common. Interestingly, the frequency of fusions was higher in low-density sites, in which 100% of the plants had at least two genotypes and the average was 3.5. In high-density sites, 62% of plants were plurigenotypic, with an average of 2.8 genotypes per plant. Additionally, we found that genotypes that shared a holdfast had a significantly higher genetic relatedness than the average in the population, compatible with a kin structure. Density dependence and kin structure suggest that the occurrence of plurigenotypic organisms is linked to environmental quality, and that kin or multilevel selection may be favouring the fusion of genetically related genets.
Año: 2015
Palabras claves: Density dependence; fusion of individuals; genetic relatedness; kelp; kin aggregation; kin selection; microsatellites.
Referencia APA: Segovia, N., Vásquez, J., Faugeron, S., & Haye, P. (2014). On the advantage of sharing a holdfast: effects of density and occurrence of kin aggregation in the kelp Lessonia berteroana. Mar Ecol, 36(4), 1107-1117.
Effects of the Discharge of Iron Ore Tailings on Subtidal Rocky-Bottom Communities in Northern Chile.
González, S., Stotz, W., & Lancellotti, D.
Some of the many mining operations that exist in northern Chile dispose their mine tailings directly into the sea. Little is known about the effects of these tailings on shallow rocky subtidal communities. This study reports these effects for an iron ore pelletization plant that has discharged for ca. 23 years in the intertidal of a cove on the exposed rocky coast of northern Chile, generating high turbidity in the water column and deposit of sediments on the bottom. A nonparametric multidimensional scaling (nMDS) ordination analysis for the species of the rocky subtidal communities, based on the Bray-Curtis dissimilarity index, showed great differences, the affected communities being dominated by incrusting invertebrates, whereas the unaffected areas at the same depth had kelp beds. The effects were observed only close to the discharge and were not observed in the more shallow water communities, which in affected and unaffected areas consisted of barren grounds dominated by calcareous algae and sea urchins. The effect on the vertical zonation pattern of communities did not produce differences in the effective diversity, which turned out to be similar among affected and control sites. This occurred because of the replacement, more than the elimination, of species on affected sites. This type of study, in which information is generally maintained in reports only seen by industry and governments, needs to be published to contribute to a more comprehensive database for the improvement of decision-making processes regarding coastal subtidal rocky communities and the effects of human activities on these environments.
Año: 2014
Palabras claves: Mining activities on the coast, discharge of suspended solids, effect of turbidity, marine assemblages, kelp beds, barren grounds, Chilean coast
Referencia APA: González, S., Stotz, W., & Lancellotti, D. (2014). Effects of the Discharge of Iron Ore Tailings on Subtidal Rocky-Bottom Communities in Northern Chile. Journal Of Coastal Research, 295, 500-514.
The Status of Kelp Exploitation and Marine Agronomy, with Emphasis on Macrocystis pyrifera, in Chile.
Buschmann, A., Prescott, S., Potin, P., Faugeron, S., Vásquez, J., & Camus, C. et al.
Kelp cultivation started in Japan, China and Korea, mainly for human consumption; new applications are still expanding. In Chile, three ‘wild’ Lessonia species and Macrocystis pyrifera are under a strong and increasing pressure of exploitation mainly for alginate production and as a source of feed for abalone. Regulatory restrictions for kelp exploitation and the increased demand for biomass provided a positive environment for the installation of a kelp farming industry. Pilot-production studies demonstrated that 200 tonnes (fresh)/ha/year can be achieved and genetic diversity and breeding studies suggested that this volume could be increased. Kelp disease research is a necessary condition for securing the future development of this industry, as are environmental studies on the impacts of large-scale aquaculture. Beyond the positive bioremediation, ecosystem service effects that kelp farming can provide, especially in a region such as in southern Chile, where intensive salmon and mussel cultivation occurs. Life Cycle Assessment suggests that the energy returns on investment in kelp farming are positive, but more detailed data are still required.
Año: 2014
Palabras claves: Kelp exploitation and farming; Life cycle assessment; Macrocystis pyrifera; Seaweed diseases; Seaweed farming environmental impacts.
Referencia APA: Buschmann, A., Prescott, S., Potin, P., Faugeron, S., Vásquez, J., & Camus, C. et al. (2014). The Status of Kelp Exploitation and Marine Agronomy, with Emphasis on Macrocystis pyrifera, in Chile. Advances In Botanical Research, 161-188
Effects of predation on diel activity and habitat use of the coral-reef shrimp Cinetorhynchus hendersoni (Rhynchocinetidae).
Ory, N., Dudgeon, D., Duprey, N., & Thiel, M.
Nonlethal effects of predators on prey behaviour are still poorly understood, although they may have cascading effects through food webs. Underwater observations and experiments were conducted on a shallow fringing coral reef in Malaysia to examine whether predation risks affect diel activity, habitat use, and survival of the rhynchocinetid shrimp Cinetorhynchus hendersoni. The study site was within a protected area where predatory fish were abundant. Visual surveys and tethering experiments were conducted in April–May 2010 to compare the abundance of shrimps and predatory fishes and the relative predation intensity on shrimps during day and night. Shrimps were not seen during the day but came out of refuges at night, when the risk of being eaten was reduced. Shrimp preferences for substrata of different complexities and types were examined at night when they could be seen on the reef; complex substrata were preferred, while simple substrata were avoided. Shrimps were abundant on high-complexity columnar–foliate Porites rus, but tended to make little use of branching Acropora spp. Subsequent tethering experiments, conducted during daytime in June 2013, compared the relative mortality of shrimps on simple (sand–rubble, massive Porites spp.) and complex (P. rus, branching Acropora spp.) substrata under different predation risk scenarios (i.e., different tether lengths and exposure durations). The mortality of shrimps with short tethers (high risk) was high on all substrata while, under low and intermediate predation risks (long tethers), shrimp mortality was reduced on complex corals relative to that on sand–rubble or massive Porites spp. Overall, mortality was lowest on P. rus. Our study indicates that predation risks constrain shrimp activity and habitat choice, forcing them to hide deep inside complex substrata during the day. Such behavioural responses to predation risks and their consequences for the trophic role of invertebrate mesoconsumers warrant further investigation, especially in areas where predatory fishes have been overexploited.
Año: 2014
Palabras claves: Rhynchocinetid shrimps, Habitat complexity, Substratum structure, Predator–prey interactions, Risk effects,Tethering.
Referencia APA: Ory, N., Dudgeon, D., Duprey, N., & Thiel, M. (2014). Effects of predation on diel activity and habitat use of the coral-reef shrimp Cinetorhynchus hendersoni (Rhynchocinetidae). Coral Reefs, 33(3), 639-650.
Formulated diets for giant chilean frog Calyptocephalella gayi tadpoles
Toledo, P., Suazo, R., & Viana, M.
In this study, we conducted an experiment to evaluate the overall effect of novel diets on the growth, metamorphosis and survival of tadpoles of the endangered giant Chilean frog Calyptocephalella gayi (previously known as Caudiverbera caudiverbera) to evaluate the potential of this species for culture and repopulation purposes. Using fishmeal as the main protein source with a substitution of either scallop viscera or Spirulina meal, three treatments were formulated to contain similar amounts of protein and energy. The experiment was run for 75 days, after which the tadpoles showed no significant differences among treatments in terms of their growth or survival. This is the first study to report positive effects of different diets on the growth and survival of tadpoles of the giant Chilean frog. Therefore, it might be possible to extend the farming of Calyptocephalella gayi for human consumption and repopulation. Nevertheless, more efforts are needed to understand their nutritional requirements to formulate appropriate diets for this endangered frog.
Año: 2014
Palabras claves: Artificial diet, nutrition, protein sources, Spirulina meal, survival.
Referencia APA: Toledo, P., Suazo, R., & Viana, M. (2014). Formulated diets for giant chilean frog Calyptocephalella gayi tadpoles. Ciencia E Investigación Agraria, 41(1), 3-4.