ALBERT

Description: Interpretation of new multichannel seismic reflection profiles indicates that the Palomares margin formed by crustal-scale extension and coeval magmatic accretion during middle to late Miocene opening of the Algero-Balearic basin. The margin formed at the transition between thinned continental crust intruded by arc volcanism and back-arc oceanic crust. Deformation produced during the later positive inversion of the margin offshore and onshore is partitioned between ~N50°E striking reverse faults and associated folds like the Sierra Cabrera and Abubacer anticlines, and N10-20°E sinistral strike-slip faults like Palomares and Terreros faults. Parametric sub-bottom profiles and multibeam bathymetry offshore, structural analysis, available GPS geodetic displacement data and earthquake focal mechanisms jointly indicate that tectonic inversion of the Palomares margin is currently active. The Palomares margin shows a structural pattern comparable to the north Maghrebian margins where Africa-Eurasia plate convergence is accommodated by NE-SW reverse faults, NNW-SSE sinistral faults and WNW-ESE dextral ones. Contractive structures at this margin contribute to the general inversion of the Western Mediterranean since ~7 Ma ago, coeval to inversion at the Algerian margin. Shortening at the Alboran ridge and Al-Idrisi faults occurred later, since 5 Ma, indicating a westward propagation of the compressional inversion of the Western Mediterranean.

Description: In the Falkland Islands, islands with invasive rats have fewer passerine species compared to islands without rats. On islands on which rats have been eradicated, passerine species richness is indistinguishable from that found on islands historically free of rats, but community composition differs between these two island types. In particular, the most dominant species on historically rat-free islands, Cinclodes antarcticus , is less abundant and prevalent on eradicated islands. We compared passerine energy flow on islands with rats, islands from which rats have been eradicated, and islands on which rats were historically absent. Passerine communities on islands historically without rats used nine times more energy than on islands with rats present. Despite equivalent passerine species richness, passerine energy flow was approximately half on islands from which rats had been eradicated compared to historically rat-free islands. Because passerine energy flow was determined by community composition and not by species richness, passerine species within this community appear to be functionally complementary and not functionally redundant. At least one species, C. antarcticus , plays an irreplaceable role. Our results also document the dramatic and lingering effects of invasive species following their eradication, and the importance of species complementarity for the resilience of community properties.

Description: A P-wave seismic velocity model has been obtained for the Central Iberian Zone, the largest continental fragment of the Iberian Variscan Belt. The spatially dense, high-resolution, wide-angle seismic reflection experiment ALCUDIA-WA, was acquired in 2012 across central Iberia, aiming to constrain the lithospheric structure and resolve the physical properties of the crust and upper mantle. The seismic transect, ~310 km long crossed the Central Iberian Zone from its suture with the Ossa-Morena Zone to the southern limit of the Central System mountain range. The energy generated by 5 shots, was recorded by ~900 seismic stations. High amplitude phases were identified in every shot gather for the upper crust (Pg and PiP) and Moho (PmP and Pn). In the upper crust, the P-wave velocities increase beneath the Cenozoic Tajo Basin. The base of the upper crust varies from ~13 km to ~20 km between the southernmost Central Iberian Zone and the Tajo Basin. Lower crustal velocities are more homogeneous. From SW-NE, the travel-time of PmP arrivals varies from ~10.5 s to ~11.8 s, indicating lateral variations in the P-wave velocity and the crustal thickness, reflecting an increase towards the north related with alpine tectonics and the isostatic response of the crust to the orogenic load. The results suggest that the high velocities of the upper crust near the Central System might correspond to igneous rocks and/or high grade metamorphis rocks. The contrasting lithologies and the increase in the Moho depth to the north evidence differences in the Variscan evolution.

Description: Abstract Erosion and deposition redistribute mass as a continental rift evolves, which modifies crustal loads and influences subsequent deformation. Surface processes therefore impact both the architecture and the evolution of passive margins. Here we use coupled numerical models to explore the interactions between the surface, crust, and lithosphere. This interaction is primarily sensitive to the efficiency of the surface processes in transporting mass from source to sink. If transport is efficient, there are two possible outcomes: (1) Faulting within the zone of extension is longer lived and has larger offsets. This implies a reduction of the number of faults and the width of the proximal domain. (2) Efficient transport of sediment leads to significant deposition and hence thermal blanketing. This will induce a switch from brittle to ductile deformation of the upper crust in the distal domains. The feedbacks between these two outcomes depend on the extension history, the underlying lithospheric rheology, and the influence of submarine deposition on sediment transport. High erosion/sedimentation during early faulting leads to abrupt crustal necking, while intermediate syntectonic sedimentation rates over distal deep submarine hotter crust leads to unstructured wide distal domains. In models where rheological conditions favor the formation of asymmetric conjugate margins, only subaerial transport of sediments into the distal domains can increase conjugate symmetry by plastic localization. These models suggest that passive margin architecture can be strongly shaped by the solid Earth structure, sea level, and climatic conditions during breakup.

Description: This study is a quantitative evaluation of historic nesting levels of the Kemp's ridley sea turtle ( Lepidochelys kempii ) in 1947 based on (1) the Herrera film of a 1947 arribada, (2) Hildebrand's 1947 report regarding the 1947 arribada shown in the Herrera film, (3) historic documentation regarding the Herrera film, and (4) current nesting characteristics related to arribada size relative to total nests for a season. Using this information in a quantitative approach, we estimate a total of approximately 26 916 nests during the 1947 arribada recorded by Herrera. Based on current nesting trends, we also predict that this would equate to approximately 121 517 total nests for the 1947 season (range of 82 514–209 953), which would represent approximately 48 607 nesting females (range of 33 006–83 981). This suggests that during and prior to the 1947 nesting season a relatively robust population of Kemp's ridleys existed, which could support arribadas consisting of at least 26 916 females. The results of the current study indicate that from 1947 through 1985 (the lowest point in the decline of Kemp's ridley nesting) the Kemp's ridley population underwent a 99.4% decline (range of 99.2–99.7%) from an estimated 121 517 nests per season in 1947 to 702 nests per season in 1985. Although the Kemp's ridley population has been recovering since the 1985 season, it has deviated from its exponential recovery rate and has declined in recent years. The current levels of nesting (12 053 nests in 2014) are still relatively low at 9.9% (range of 5.7–14.6%) of the total estimated nests that occurred in 1947. It is currently not clear whether this population will recover to historic levels considering recent nesting trends and due to a variety of threats that may hinder its recovery.

Description: 2D seismic reflection data tied to biostratigraphical and log information from wells in the central and south-eastern Alboran Sea have allowed us to constrain the spatial and temporal distribution of rifting and inversion. Normal faults, tilted basement blocks and growth wedges reveal a thinned continental crust that formed in response to NW-SE extension. To the east a secondary SW-NE trend of extension affects the transitional crust adjacent to the oceanic Algerian Basin. The maximum thickness of syn-rift sediments is ~3.5 km and the oldest recorded deposits are Serravallian. The WNW-ESE Yusuf fault formed a buttress separating and accommodating variable extension between two different tectonic domains: the thinned continental crust of Alboran and the oceanic spreading of the Algerian Basin. Late Tortonian to present-day NW-SE Africa/Eurasia plate convergence drove shortening and reactivation of some of the earlier extensional structures as reverse and strike-slip faults, forming complex, compartmentalised sub-basins. Tectonic inversion coexisted with the formation of new faults and folds. Inversion was partial along the Habibas Basin and Al-Idrisi fault, but complete along the Alboran Ridge, where some SW-NE trending faults were perpendicular to the recent NW-SE plate convergence and were reactivated as thrusts. The WNW-ESE Yusuf fault is oblique to the convergence vector and therefore, reactivation is mainly expressed as transpressional deformation. Volcanic rocks intruded along the Alboran Ridge and Yusuf faults during the latest stages of extension, formed rheological anisotropies that localised the later inversion.

Description: Escaping seed predation is a classic “economy of scale” hypotheses ( predator satiation hypothesis, Psh ) to explain the selection for the synchronous production of massive and nil seed crops (masting) in plants. The Psh postulates that predator satiation occurs through a combination of (1) “functional satiation,” as not all seeds can be consumed during a massive crop, and (2) “numerical satiation,” as predator populations collapse during poor crop years. Many studies advocate for the Psh , but few have investigated the importance of masting compared to other factors for the control of predation extent. Namely, environmental cues prompting masting could also determine predator's success and, ultimately, influence directly and independently seed predation intensity. We explored this question in Mediterranean oaks, as they exhibit strong masting behavior; acorns are heavily predated upon by weevils; and rainfall stochasticity drives masting and the emergence of adult weevils from the soil. Results of two mid-term studies (4 and 11 yr) showed that acorn production and predation were highly variable across years, while the abundance of adult weevils was positively related to autumn rainfall and to the number of infested acorns the previous years. Ultimately, acorn predation was negatively influenced by inter-annual fluctuation of seed production (masting) yet, mainly and positively, prompted by autumn rainfall and acorn crop size (only in one site). Our results highlight the relevance of masting to reduce seed predation. Yet evidences that rainfall stochasticity directly determines the success of weevils, and it independently influences seed predation extent, indicate that environmental cues prompting masting may also fine-tune the output of this reproductive behavior. Additionally, local differences suggest that the relevance of masting may change with tree characteristics (low vs. high seed production) and landscape structure (isolated vs. dense forests). We also discuss what can be the effects of increasing drought in Mediterranean areas for this antagonistic interaction, triggered by rainfall.

Description: Rural areas particularly suffer from economic crises where they overlap with long-term negative effects of climate change. Here, we introduce the concept of mycotourism by means of mushroom-related industries in central-northeastern Spain. We describe how this novel branch of eco-tourism can help stabilize social and political structures. Likewise, we illuminate the potential of mycotourism to compensate for some losses related to widespread unemployment and summer drought, as well as to generate unexpectedly fruitful research opportunities. Focussing on Spain's emerging black truffle industry, we recommend a stronger involvement of natural sciences, conservation services, and management strategies in commercial endeavors. We emphasize the relevance of direct and indirect climatic impacts on ecological and societal systems as well as on economic markets. Moreover, we stress the importance of a vital science–policy interface at various scales, with immediate opportunities for sustainable landscape protection and the preservation of biological diversity.

Description: A paleomagnetic and magnetic fabric study is performed in Upper Jurassic gabbros of the Central High Atlas (Morocco). These gabbros were emplaced in the core of pre-existing structures developed during the extensional stage and linked to basement faults. These structures were reactivated as anticlines during the Cenozoic compressional inversion. Gabbros from 19 out of the 33 sampled sites show a stable characteristic magnetization, carried by magnetite, which has been interpreted as a primary component. This component shows an important dispersion due to post-emplacement tectonic movements. The absence of paleo-position markers in these igneous rocks precludes direct restorations. A novel approach analyzing the orientation of the primary magnetization is used here to restore the magmatic bodies and to understand the deformational history recorded by these rocks. Paleomagnetic vectors are distributed along small-circles with horizontal axes, indicating horizontal-axis rotations of the gabbro bodies. These rotations are higher when the ratio between shales and gabbros in the core of the anticlines increases. Due to the uncertainties inherent to this work (the igneous bodies recording strong rotations), interpretations must be qualitative. The magnetic fabric is carried by ferromagnetic (s.s.) minerals mimicking the magmatic fabric. AMS axes using the rotation routine inferred from paleomagnetic results, resulting in more tightly clustered magnetic lineations which also become horizontal and are considered in terms of magma flow trend during its emplacement: NW-SE (parallel to the general extensional direction) in the western sector and NE-SW (parallel to the main faults) in the easternmost structures.

Description: The Rheic Ocean suture resulted from pre-Carboniferous oceanic subduction followed by Late Devonian-Carboniferous Variscan collision. In SW Iberia, this suture has been classically located along the boundary between the Ossa-Morena and South Portuguese Zones based on the presence of three units: (i) A conspicuous metamafic unit (Beja-Acebuches) that crops out along this boundary and has been interpreted as a pre-Carboniferous Rheic Ocean ophiolite; (ii) a low-grade metasedimentary unit with minor MORB-like metabasalts (Pulo do Lobo unit), thought to represent a Rheic Ocean subduction-related accretionary prism; and (iii) the allochthonous Cubito-Moura unit that contains high-pressure and ophiolitic-like rocks. We report new structural and geochronological data that allow us to reinterpret the origin and internal structure of the Beja-Acebuches and the Pulo do Lobo units. Thus, both the Beja-Acebuches protoliths and the Pulo do Lobo metabasalts would have been formed in the context of an intracollisional extensional stage that interrupted the Variscan collision at early Carboniferous time, after the Rheic Ocean consumption and the first continental collision. Later on, collision was resumed in an oblique left-lateral regime that gave way to coeval frontal (folds and thrusts) and lateral (shear zones and strike-slip faults) structures, with variable pressure-temperature conditions and space distribution along time. As a consequence of the superposition of transtension and complex transpression, the Rheic suture in SW Iberia has an obscure nearly cryptic appearance.