Sexual traits plasticity of the potentially invasive limpet Bostrycapulus odites (Gastropoda: Calyptraeidae) within its natural distribution in South America

The slipper limpet Bostrycapulus odites has recently been reported as an introduced species on the Spanish Mediterranean coast. Another species in the family Calyptraeidae, Crepidula fornicata, is a problematic invasive species in the Northeast Atlantic, which makes the closely related Bostrycapulus introduction a matter of concern. Information on the biology of B. odites in its natural environment can facilitate predictions on where the species could find favourable conditions for settlement and expansion. Size and sex were recorded for individuals in four populations over 2600 km of the Southwestern Atlantic shoreline, in Argentina and Brazil, covering the whole native latitudinal range of this widely distributed species. Animals were collected by hand in the intertidal or by SCUBA in subtidal locations; specimens were examined to determine shell length, sex, and the presence and number of brooded egg capsules in females. Mean shell length for the whole population did not differ significantly among populations. However, this species experiences sequential hermaphroditism (protandrism), and the size at sexual maturity (minimum male size) increased significantly with latitude. The fecundity of females at all sites increased with size, and the number of brooded egg capsules as well as the average size of capsules was larger in bigger individual females; however, mean fecundity varied among sites independent of mean female body size. This limpet species modifies its reproductive traits with local conditions, and sexual characters develop earlier in more temperate localities.     

Cathaysian slivers in the Philippine island arc: geochronologic and geochemical evidence from sedimentary formations of the west Central Philippines

The use of geodynamic information contained in sedimentary rocks has only recently been extended into the tectonic reconstruction studies of the Philippine archipelago vis-à-vis the rest of the Southeast Asian region. We present here a comparative assessment of clastic units from the western Central Philippines, particularly from the islands of Mindoro, Panay and Palawan, and propose their likely association with sources of Cathaysian origin. Geochronological data from sedimentary formations in the study areas register U–Pb dating peaks at 185–140 Ma, 140–120 Ma and 112–90 Ma. These are similar to those observed of detrital zircons from rocks of Cathaysian origin in Taiwan and Southern China that chronicle the Yanshanian magmatic events. These same formations also record an older intercept at 1.9–1.85 Ga that likely corresponds to a regional continental orogenic episode recorded in the late Paleoproterozoic Cathaysian block. Major (e.g. Al₂O₃/TiO₂) and trace-element (e.g. Y/Ni vs Cr/V) signatures of these sedimentary formations reflect stronger influences from granitic sources than mafic–ultramafic inputs that should otherwise be expected, considering their current oceanic island arc settings. Their La/Th and Th–Co–Zr/10 ratios also reveal continental island arc and active or passive continental margin depositional settings typical of rocks from the Palawan Microcontinental Block. New geochronological and geochemical data from the clastic rocks of northwest Mindoro, in addition to those already published for the other regions of the Palawan Microcontinental Block, provide further evidence for the amalgamation of fragments of Cathaysian origin within the Philippine island arc system.     

Petrological and geochemical characteristics of the Samar Ophiolite ultramafic section: implications on the origins of the ophiolites in Samar and Leyte islands,Philippines

Cretaceous ophiolites and ophiolitic fragments occur in the Samar and Leyte islands in eastern central Philippines. The Samar Ophiolite is a complete crust–mantle sequence exposed in southern Samar, whereas the Tacloban and Malitbog ophiolite complexes are, respectively, located in the northeastern and southwestern portions of the nearby Leyte island. Despite the close proximity of these islands, the genetic relationship of these ophiolites and ophiolitic complexes, if any, remains to be elucidated. We present here new petrographic and geochemical data on the harzburgites and dunites of the ultramafic section of the Samar Ophiolite. These mantle peridotites are highly depleted residues which have low modal pyroxene content, high spinel Cr# (=0.62–0.79), and slightly enriched light rare earth element abundance with depletion in Zr and Ti. Such characteristics are typical of supra-subduction zone peridotites and strongly contrast with the abyssal signatures of the Tacloban and Malitbog ophiolite complexes. The absence of a structure between these adjacent ophiolite fragments initially hints that they form a single oceanic crust. However, with our new results, we suggest other possible mechanisms that could explain the relationship of these ophiolites.     

Impact of salt and frost weathering on the physical and durability properties of travertines and carbonate tufas used as building material

This study aims to understand the effect of salt and frost crystallisation on the petrophysical and durability properties of representative types of travertine and carbonate tufas. Results demonstrate that the studied travertines and tufas exhibit a very high durability against salt and ice crystallisation cycles, compared to carbonates rocks with similar porosity values. The variation of the loss of mass, effective porosity, capillary absorption coefficient, ultrasonic wave velocity and attenuation, and compressive strength was scarce during weathering tests. The evolution of petrophysical properties was slightly more intense after 30 cycles of salt crystallisation than 100 cycles of freeze–thaw. Petrophysical and durability properties of the travertines and carbonate tufas depend on porosity fraction and on the manner in which the vuggy porosity is connected. In the travertine facies, vuggy macropores show little connection and can be considered as separate-vug porosity. Their addition to interparticle porosity increases effective porosity and reduces their mechanical strength but does not significantly increase capillary transport and the effectiveness of salt and ice action over the stone. On the contrary, in the carbonate tufas, vugs act as touching-vug pores, as capillary imbibition coefficients reveal. However, scanning electron microscopy displays that they underwent microcracking processes related mainly to both thermal stresses and/or ice and salt pressures. These microcracks present little connection, and they do not enhance noticeably the water flow or decrease the mechanical properties. These results are finally discussed in terms of a nonlinear decay pattern, which with long periods of apparent stability might be followed by rapid and catastrophic decay.     

Characterization of flow and transport dynamics in karst aquifers by analyzing tracer test results in conduits and recharge areas (the Egino Massif,Basque Country,Spain): environmental and management implications

Karst aquifers contribute to supplying drinking water to almost a quarter of the world´s population. Their complex dynamics requires specific approaches aimed at recognizing their singularities, analyzing its vulnerability, and ensuring water resources quality. In this paper, the results of processing and modeling five breakthrough tracer curves obtained under different hydrodynamic conditions in the main conduit of Egino karst aquifer (Basque Country, Spain) are analyzed together with those involving pressure injections of the tracer in the saturated zone of the karst massif recharge area. In the conduit, transport is immediate and highly efficient (recovery rates above 84% and dispersion coefficients from 15.04 to 84.35 m²/min); tracer retentions increase as flow rates decrease and no significant contributions to its surroundings are observed. In contrast, tracer transport from the massif recharge area is more complex: after injection at a pressure of 1 MPa, most tracer remains in the surrounding of the injection borehole, retained in a saturated medium of low effective fracture porosity (? _f ?=?1.02?×?10^?4, assuming a radial divergent flow model); subsequently, the main tracer mobilization to the spring was registered with the first rains, with 0.088 m/min mean velocity and high concentrations per unit mass being injected (C _p /M₀?=?0.03 mg/L/kg), which is evidence that the tracer reaches soon the karst conduit network. In any case, a decreasing tracer presence is registered at the injection zone during a hydrological cycle. In both cases, the observed non-linearity of transport processes should be considered in the development of vulnerability approaches, modeling efforts, and mapping. Furthermore, in the case of karst massif recharge areas, as the presence of pollutants may have a significant impact on the springs and persist over time, their management and protection needs must be revised in each specific site. Simultaneously, quality-monitoring programs at the springs must be adapted to the aquifers recognized dynamics.     

Deep-seated gravitational slope deformations triggered by extreme rainfall and agricultural practices (eastern Michoacan,Mexico)

The study of deep-seated gravitational slope deformations (DSGSD) in Mexico is scarce; therefore, their localization and causes are highly overlooked. The present paper examines the characterization of the DSGSD of Jungapeo and Las Pilas in eastern Michoacan state, currently active and endangering their inhabitants. An integrated study, including detailed lithology, morpho-structural inventories, analysis of land use, and pluviometric regime, was performed and complemented with differential global positioning system monitoring networks. Both landslides developed over highly weathered volcano-sedimentary rocks. On the one hand, the Jungapeo landslide has an estimated volume of 990,455 m³ with steady decreasing velocity rates from 41 to 15 cm/month in the first monitoring period to 13–3 cm/month in the last one. On the other hand, the Las Pilas landslide estimated volume is about 1,082,467 m³ with a stable velocity rate of 1.3 to 0.1 cm/month. Despite the multi-storeyed style of activity, two behaviors of instability were distinguished: slow deformation and secondary landslide stages. The conditioning factors for slow deformation in both DSGSD are the combination of weathered lithology with clay- and sand-rich content, and the shift toward intensive monoculture. The triggering factor is related to excess water produced by an inefficient flood-irrigation system that also generates an atypical acceleration behavior in both landslides during the dry season. The DSGSD activity thus predisposes the generation of tension cracks and secondary scarps from which the collateral landslides are triggered by atypical rainfall, such as that of 2010.     

Recommendation system to determine suitable and viable hiking routes: a prototype application in Sierra de las Nieves Nature Reserve (southern Spain)

This paper describes a system for recommending hiking routes to help manage hiking activities in a protected area. The system proposes various routes, based on five criteria that maximize some aspects of hikers’ requirements (by analyzing the viability and difficulty of the trails) and also those of protected areas managers (by proposals to relieve congestion in areas already used for hiking and to promote awareness of new ones, as a contribution to environmental education). The recommendation system uses network analysis, multi-criteria decision analysis and geographic information system by free software tools: PgRouting, PostgreSQL and PostGIS. This system has been tested in Sierra de las Nieves Nature Reserve (Andalusia, Spain). Of the 182 routes obtained by the system, 62 (34%) are considered viable for hikers in Sierra de las Nieves, taking into account the type of user most likely to visit this protected area. Most routes have a high difficulty level, which is coherent with the mountainous character of the protected area.     

Risk perception in Unión Juárez,Chiapas, Mexico

The proximity to the Tacaná volcano, to the subduction zone between the Cocos and North America plates, to the Mexican coast, and to the active geologic Polochic-Motagua fault makes the population of Union Juarez (UJ), Chiapas, Mexico, exposed to many natural hazards including hurricanes, earthquakes, landslides, and volcanic eruptions. We assessed the risk perception of UJ, and our findings indicate that the community has moderate level of risk perception according to the scale of the National Center for Disaster Prevention of Mexico. The UJ’s risk perception is mainly dependent on gender and religion because females unlike males in case of disasters and emergencies: (1) believe that it is necessary to improve their preparedness; (2) trust the local civil protection authorities; (3) would know how to respond; (4) would follow the established protocols; and (5) would not relocate. On the other hand, non-religious people know better the protocols to follow in the event of disasters than the religious population. Besides, the community of UJ reasonably perceives earthquakes and extreme rains as the main hazards that they are exposed to, while volcanic hazards are considered less important although the town is located very close to the Tacaná volcano that has been active during the last 30 years. The local population lacks of proper knowledge and resources to develop adequate disaster mitigation plans. Surprisingly, the work of the local civil protection is considered poor. Our results can be used for local authorities as a tool to strength the disaster prevention actions in UJ.

     

Holocene environmental change on the Atlantic coast of NW Iberia as inferred from the Ponzos wetland sequence

The intertidal environment of the Ponzos beach (NW Iberian Peninsula) hosts a sedimentary sequence (including large wood fragments) deposited during the first half of the Holocene in a hygrophilous continental wetland. Pollen and macrofossil data alongside radiocarbon dating allow reconstruction of the changes that occurred during the Early and Middle Holocene in the landscape of the NW Iberia coastal lowlands, as well as the local wetland plant communities, in response to the climate variations and the eustatic sea-level oscillations. The sequence represents the evolution of a coastal wetland from its initial phases as a hygrophilous wetland towards the subsequent installation of a freshwater lagoon. Pollen data show the dominant role of Atlantic (mainly deciduous) woody taxa, the scarcity of conifers and the lack of Mediterranean elements in the coastal landscapes around the Ponzos site. The presence and abundance of some taxa such as deciduous Quercus, Castanea, Fagus, Tilia and Ulmus during the Early Holocene provides further support for the occurrence of glacial refuges in the Cantabrian-Atlantic area during the Last Glaciation. The diverse vegetation that characterizes the modern landscapes in this territory established later, spreading from these glacial reservoirs of biodiversity. In this sense, the notable and early presence of Fagus at the beginning of the Holocene, a tree also previously recorded during several phases of the Last Glacial Cycle on the NW Iberia coasts, is noteworthy. In addition, during the Early and Middle Holocene are recorded other trees that are currently extirpated as natural taxa in the area, such as Pinus, Tilia and Carpinus.