Browsing by Author "Fariña, JM"

Now showing 1 - 4 of 4
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    Bias in evaluating the effects of marine protected areas
    (2004) Edgar, GJ; Bustamante, RH; Fariña, JM; Calvopiña, M; Martínez, C; Toral-Granda, MV
    Analysis of ecological baseline data collected for key resource species within the Galapagos Marine Reserve indicates that variation in animal density associated with the location of fully protected zones can be comparable to protected area effects. Even with a high level of interspersion between conservation, tourism and fishing management zones, major differences in densities of economically important species were evident between zone types prior to enforcement of fishing restrictions. Densities of the most valuable fishery resource, sea cucumbers, were three times higher in zones that remained open to fishing compared to 'no-take' conservation zones, and densities of sharks were five times higher in tourism zones than fishing or conservation zones. These results highlight bias in the socio-political processes that can accompany selection of marine protected areas, where fishers attempt to minimize perceived impacts on their livelihood by locating large protected zones in resource-poor areas, and tourism operators and sport divers argue for protection of areas containing atypically-interesting features. Bias in the location of fully protected zones can seriously confound 'control-impact' field investigations when data prior to prohibitions on fishing are lacking, including meta-analyses, which arc dominated by such potentially systematically biased studies.
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    Effect of drift kelp on the spatial distribution pattern of the sea urchin Tetrapygus niger
    (2001) Rodríguez, SR; Fariña, JM
    Geostatistical analysis was used to investigate the effect of drift kelp on the spatial distribution of the sea urchin Tetrapygus niger. The positions of all sea urchins were mapped in four experimental plots in the rocky intertidal zone of the central Chilean coast. When drift macroalgae were added, the sea urchins left the substratum irregularities, increased in number inside the experimental plots, and tended to form a dense aggregation around the kelp. After the drift macroalgae was removed, the aggregations disappeared and the sea urchins returned to the depressions and/or interstices of the substratum. The results suggest that the influx of drift kelp is the triggering factor in the formation of dense aggregations of this species.
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    Nutrient exchanges between marine and terrestrial ecosystems
    (2003) Fariña, JM; Salazar, S; Wallem, KP; Witman, JD; Ellis, JC
    1. The movement of materials and organisms between ecosystems is a common process in nature.
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    Nutrient transfer from sea to land
    (2006) Ellis, JC; Fariña, JM; Witman, JD
    The structure of communities is influenced by the transport of resources across ecosystem boundaries. Seabirds are capable of introducing large amounts of marine-derived nutrients to land, thereby modifying resource availability to terrestrial species.