A conceptual framework for the integral management of marine protected areas

A general conceptual framework for the management of marine protected areas (MPAs) was developed. The driver-pressure-state-impacts-response (DPSIR) framework was used to determine the elements affecting MPAs. The developed evaluation framework helped to select an appropriate suite of indicators to support an ecosystem approach, an assessment of the MPAs functioning and policy decisions. Gaps derived from the management and policy responses in the MPAs were also outlined. It was concluded that the DPSIR framework can help to simplify the complexity of MPA management. This document is a tool for policy makers, scientists and general public on the relevance of indicators to monitor changes and MPAs management.     

Marine ecosystem-based management in the Southern Cone of South America: Stakeholder perceptions and lessons for implementation

Ecosystem-based management (EBM) has recently received considerable attention. However, examples of empirical approaches to marine EBM are scarce. Therefore, empirical information on the presence of EBM elements within existing policies and the way they may provide settings and lessons for EBM implementation is timely. This study analyses stakeholders’ perceptions on the existence of EBM principles in current marine management practices and policies, and how they determine perceptions for success and satisfaction regarding coastal management within selected case studies drawn from four developing countries in the Southern Cone of South America. Patterns of response across study sites show that although EBM principles as such are not explicitly included in management/conservation plans, there are policies (mainly local), which generate conditions for more explicit inclusion of them. These are based on participatory bottom-up planning, place-based management and consensus reaching: all elements included within the theoretical literature on EBM implementation.     

Comparison between amphipod assemblages associated with Caulerpa racemosa var. cylindracea and those of other Mediterranean habitats on soft substrate

The spread of the invasive alga Caulerpa racemosa var. cylindracea in shallow-water habitats can present different faunal assemblage composition. We compared the amphipod assemblages associated with C. racemosa and natural habitats found on shallow-water Mediterranean soft substrata. Four vegetated habitats were compared: C. racemosa, Caulerpa prolifera, Cymodocea nodosa and Posidonia oceanica with unvegetated substrata. Samples were collected during two sampling periods (September 2004 and March 2005). A total of 63 amphipod species were recorded. The results showed that the vegetated habitats sampled, including C. racemosa stands, supported a higher abundance and species richness of amphipods. Furthermore, the assemblage structure differed between the different habitats, while the abundance of some species was significantly different, depending on habitat. For example, Microdeutopus obtusatus was favoured by C. racemosa habitat; Ampelisca diadema was associated with C. prolifera beds; and Hyale schmidti was more abundant in P. oceanica meadows. Habitat invasion by C. racemosa can exert an important influence on biotic assemblages, modifying habitat structure and associated fauna.     

Hydroid assemblages from the Southwestern Atlantic Ocean (34–42° S)

This paper provides updated taxonomic knowledge about hydrozoan species and provides ecological information including geographical and bathymetric distributions and biological substrata for the various hydroid assemblages from the Sub-Antarctic Biogeographical Region, mainly Buenos Aires and the Uruguayan coasts. Five of the 41 species found are new records for the study region. Thirty-one species (75.6%), all found at depths of less than 80 m, have cosmopolitan distributions. Biodiversity decreased markedly below 80 m depth, where nine species (≈22%) distributed in the Southern hemisphere and one endemic species (2.4%) were found. Most species were non-specific epizoites, occurring on diverse substrata. A non-parametric multivariate similarity analysis revealed nine species groups that were correlated with large-scale and local oceanographic patterns and with the availability of suitable substrata. The main hydroid substrata for eight of the groups were cnidarians, molluscs (mainly blue mussels), quartzite rocks and sponges. In a single group found in Patagonian scallop beds, the main biological substrata were polychaete tubes, other hydroids and scallops.     

Behaviour of a new type of Runge–Kutta methods when integrating satellite orbits

Recently, González, Martín and Farto have developed new numerical methods (RKGM methods) of Runge–Kutta type and fixed step size for the numerical integration of perturbed oscillators. Moreover, it seems natural to study the behaviour of these new methods for the accurate integration of orbital problems after the application of linearizing transformation, such us KS or BF due to the fact that in these variables, the structure of the problem is of the form of perturbed oscillators, for which the methods constructed are indicated. In this paper, we check the efficiency of these new methods when integrating the satellite problem. The RKGM methods show a very good behaviour when they compete with other, classical and special, methods. This revised version was published online in July 2006 with corrections to the Cover Date.     

Characterization of alluvial bajada facies distribution using TM imagery

Automatic mapping techniques using multiband satellite image information have been used to study sediment grain‐size variations on an alluvial bajada. A previous study of sparsely vegetated alluvial surfaces in central‐western Argentina showed that the reflectivity recorded in seven‐band Landsat TM images is controlled by sediment composition, age and grain size. At diameters >4 mm, clast composition influences image information, while at grain sizes smaller than sand, clay mineralogy begins to influence spectral characteristics. The progressive increase in desert varnish and the loss of fine grain‐size fractions as a result of deflation cause the age influence. The bajada sedimentary environment is well suited for testing the influence of grain‐size variability on image recovery, as most drainage basins are small and sourced by a single geological unit, which produces compositionally homogeneous alluvial surfaces. Additionally, most drainage lines are active within intervals of 10–50 years, reducing the effect of surface ageing. Larger than average drainage basins produce oversized drainage lines that disrupt the bajada, generate individual alluvial fans and have slightly different compositions. Two typical bajadas were selected to map grain‐size characteristics using automatic classification techniques. The obtained classes were checked in the field, and grain‐size and compositional counts were completed. Although both bajadas are very different in composition, most grain‐size curves showed similar shapes, suggesting that deposition took place by the same process (hyperconcentrated flash floods). The values of the median and mean were consistent across the same class between both bajadas. Thus, unsupervised classification techniques are useful for mapping sediment grain size, although minor field control is needed. Image classes represent areas of similar grain size, which are elongated parallel to the mountain front in an active alluvial bajada, indicating a homogeneous distribution of sedimentary processes along strike. Changes in the width of image classes indicate different downstream fining rates closely related to the topographic gap and the slope change rate. In contrast to bajadas, alluvial fans have semi‐circular belts and a pie‐piece‐shaped area in which most active streams are located. Thus, unlike fans, bajadas lack autocyclic mechanisms for producing heterogeneous sedimentary sequences. The sedimentary log of an ancient bajada was measured in order to show the influence of allocyclic factors in the absence of autocyclicity.     

Ultraviolet radiation constraints around the circumstellar habitable zones

Ultraviolet radiation is known to inhibit photosynthesis, induce DNA destruction and cause damage to a wide variety of proteins and lipids. In particular, UV radiation between 200 and 300 nm becomes energetically very damaging to most of the terrestrial biological systems. On the other hand, UV radiation is usually considered one of the most important energy source on the primitive Earth for the synthesis of many biochemical compounds and, therefore, essential for several biogenesis processes. In this work, we use these properties of the UV radiation to define the boundaries of an ultraviolet habitable zone. We also analyze the evolution of the UV habitable zone during the main sequence stage of the star. We apply these criteria to study the UV habitable zone for those extrasolar planetary systems that were observed by the International Ultraviolet Explorer (IUE). We analyze the possibility that extrasolar planets and moons could be suitable for life, according to the UV constrains presented in this work and other accepted criteria of habitability (liquid water, orbital stability, etc.).