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Abstract. We describe the basic ecology of two key-hole limpets, Fissurella crassa and Fissurella limbata , which are heavily harvested by coastal shellfishermen (mariscadores) at the rocky intertidal of central Chile. The ecological role of human predation on these species was assessed. Anthropic exclusion from a stretch of the rocky intertidal at Las Cruces (non-harvested area) for about two and a half years resulted in changes of the densities and size distributions of these fissurelid species as compared to populations in control zones (harvested area). Differential human predation generates, on key-hole limpets, responses of different intensities related to the accessibility of man to the mesohabitats (sheltered platforms, exposed platforms and vertical walls) and fringes of the intertidal (mid-low intertidal and Lessonia nigrescens fringe). Thus, size distributions and mean densities of both fissurelids differ widely between the harvested and non-harvested areas on both platform habitats but not on vertical walls. In the mid-low intertidal fringe, differences are greater than in the less accessible L. nigrescens intertidal fringe. Moreover, we discuss the way in which other species, directly harvested by mariscadores (i. e., the mollusc Concholepas concholepas) can affect the keyhole limpet populations of central Chile rocky shores. Finally, we highlight the ecological role of these limpets on the dynamics of intertidal ecosystems and how they can modify community landscape. 相似文献
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Juan C. Castilla 《Marine pollution bulletin》1983,14(12):459-464
Since 1938, untreated copper mine tailings of Potrerillos and El Salvador have been disposed into the sea at Chañaral, Chile (26° 21′ Lat. S., 70° 42′ Long. W.). Over 220×106 t of sediments have been dumped. This pollution has caused drastic geomorphological changes in the c. 16 km contaminated area. The occurrence of new artificial beaches and modification of coastal contours are reported. Sandy beach macrofauna monitoring (1975–1982) demonstrated a progressive lowering of density and biomass in those communities affected by copper mine tailings. 相似文献
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To understand the dynamics of small populations in arid environments, particularly in small insular ecosystems, it is crucial to understand the interactions between species inhabiting these environments. Here we investigate the interactions between lizards and scorpions in a small arid insular ecosystem in the Mediterranean. Experimental observations suggest that scorpions are regarded as prey by lizards. However, the response of lizards was sex-dependent, with males being more likely to attack scorpions than females. This can be associated with the larger body and head size, and bite forces in males, presumably making scorpions a profitable prey. Predation on lizards by scorpions has been also documented, suggesting a classic case of cross predation. 相似文献
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No-take Marine Protected Areas (Nt-MPAs) constitute an indispensable tool for biodiversity conservation. Nevertheless, there are other instruments such as marine coastal co-management policy frameworks which may be also considered as tools for conservation or as ancillary conservation instruments. Using focus groups, semi-structured interviews and survey questionnaires we analysed small-scale artisanal fishers' perceptions towards a coastal co-management regime in Chile and the potential to generate capacities and a social setting to scale-up marine conservation. Empirical evidence from the study shows artisanal fishers have indeed been empowered through the coastal co-management experience; however, there exist heterogeneity in their willingness to participate in the creation of Nt-MPAs, mainly determined by occupational mobility. Chilean artisanal fishers strongly support a bottom-up process in the conservation of marine biodiversity, though the need for top-down steering and guidance is also stressed, especially regarding enforcement. 相似文献
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Andrés Marín Stefan Gelcich Gonzalo Araya Gonzalo Olea Miguel Espíndola Juan C. Castilla 《Marine Policy》2010
In 2010, a tsunami generated by a magnitude 8.8 earthquake struck the central-south zone of Chile. This short communication reports the direct impacts on the small-scale artisanal fishing capacity and coastal livelihoods along approximately 600 km of the coastline. Despite the magnitude of the catastrophe, the absence of official warnings, and the failure of telecommunication networks only 8 fisher victims were reported out of a total death toll of more than 170. Results show that this trend is explained by socio-cultural assets and a natural hazard subculture. This highlights the need to integrate contextual and behavioural approaches in disaster management and rehabilitation policies. 相似文献
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A worldwide database of liquefaction-induced sand blows has been compiled to generate empirical relationships between earthquake
parameters and sand blow geometries. Curves resulting from these empirical relationships can be used afterwards for the study
of historic and pre-historic earthquakes that formed sand blows. This database only incorporates instrumental earthquakes
inducing sand blows, characterised in terms of magnitude (Mw), hypocentral location and focal mechanism solution. Two relationships
are herein presented. The first curve, minimum likelihood of liquefaction occurrence (magnitude/epicentral distance), displays
a logarithmic behaviour, as others already proposed. The second curve of sand-blow diameter vs epicentral distance is the
first proposal of this kind, whose shape follows a negative power-law. Magnitude estimations of (pre-)historic earthquakes
then may be attempted through these empirical relationships. Resulting magnitudes derived from these curves should be mostly
considered as underestimated. The curves will reflect actual magnitudes only if, correspondingly, the farthest and largest
blow has ever been reported during the after-earthquake survey. Following the same principle, a magnitude estimation resulting
from the measuring of a sand blow can only be considered as minimal because it is almost impossible to ascertain that the
measured feature is the biggest one produced by the earthquake under evaluation. Finally, these results call for thorough
surveys of induced effects after every future moderate-to-large earthquake, as any empirical relationship simply improves
by incorporating new data. 相似文献
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Groundwater Modeling with Stakeholders: Finding the Complexity that Matters 总被引：2，自引：0，他引：2 
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下载免费PDF全文 Juan Carlos Castilla‐Rho 《Ground water》2017,55(5):620-625
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In this study, we provide the first evidence of scavenging behaviour in the spiny-tailed agamid lizard (Uromastyx aegyptia microlepis), a species which heretofore has been considered a strict desert herbivore. We examined 294 faecal samples collected in the desert of Qatar and found that 84% of the faeces (n = 247) contained exclusively plant material. Grains of barley (Hordeum vulgare) were present, suggesting that Uromastyx can benefit from the food provided to livestock when wild plants are scarce. We also found remains of invertebrates, vertebrates and stones in the lizard faeces. The type of vertebrate remains found suggests scavenging behaviour and some flexibility in feeding behaviour where food resources are scarce. Overgrazing by camels and goats in the area may affect food availability for Uromastyx populations, suggesting the need for conservation measurements in the Qatar desert. 相似文献
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Marine environmental impact as a result of copper mine tailing dumping in the sea is studied at Chañaral (North of Chile). These dumpings, from the copper mine El Salvador, have hindered harbour activities, caused geomorphological coastal modifications and affected seriously marine coastal ecosystems and recreational activities. At the old dumping site, Chañaral Bay (1938–1974), nearly 150 million tons of fine sediments were accumulated. Tailing discharges at the new dumping site, Caleta Palito, about 8 km north of Chañaral Bay are accumulating approximately at the rate of 25 000 tons of fine sediments per day, plus unknown quantities of chemicals (Cu, As, CN?). From January 1975 to July 1976, this site has received over 13 million tons of sediments which has caused deterioration of the marine coastal environment, reduction in light penetration and high mortalities among marine invertebrates, fishes and algae. 相似文献