66 research outputs found

    Gizzard contents of the Smooth-billed Ani Crotophaga ani in Santa Cruz, Galapagos Islands, Ecuador

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    The Smooth-billed Ani Crotophaga ani was introduced to the Galapagos archipelago in the 1960s, since when its population has grown signiïŹcantly. We studied the dietary items in the gizzards of 56 anis sampled on the island of Santa Cruz. We conïŹrmed that the diet of C. ani consists primarily of invertebrates and plant material, including native species and non-native invasives. The second most abundant seed in the anis’ diet was that of the highly invasive plant, Rubus niveus. Our ïŹndings suggest that C. ani poses a threat to the Galapagos ecosystem by dispersing seeds of non-native plants and by competing with other insectivorous species on the islands. Furthermore, the discovery of a Darwin’s Finch nestling in the gizzard of one C. ani establishes direct predation by this species on native birds

    Sharing land with giants: Habitat preferences of Galapagos tortoises on farms

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    One of the most pressing dilemmas of our time is determining how to satisfy the demands of a growing human population while still conserving biodiversity. Worldwide, land modification to accommodate human resource needs has caused significant declines in wildlife populations. To help minimize biodiversity loss, we must support wildlife on human-dominated land, such as farms and urban areas, but our knowledge of how to do so is lacking. Agriculture is a major driver of land modification; but also has the potential to play a role in conserving biodiversity. To support critically endangered ecosystem engineers that use farms, such as giant Galapagos tortoises, we need to understand the characteristics encouraging or hindering them. To quantify tortoise habitat preferences, we assessed the relationship between tortoise density, habitat structure, and land-use type, by recording tortoise density on farms on Santa Cruz Island, Galapagos, over two years. Tortoise density was lowest in abandoned farmland and highest in tourist areas and was most strongly positively correlated with abundant ground cover, short vegetation, and few shrubs. The habitat features favoured by tortoises could potentially be manipulated to help support tortoise conservation on farms. Measuring wildlife preferences in human-dominated areas is an important step towards balancing biodiversity conservation and human-enterprise

    ED011. Levantamiento de lĂ­nea base de la diversidad de insectos en 40 fincas en Santa Cruz, GalĂĄpagos

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    Agricultural production in Galapagos began in the early 20th century on the 4 inhabited islands. Currently, very little is known about the number, abundance and distribution of insect and plant species in the agricultural area. Information on the presence of invasive species and their impacts on agricultural production is also limited. To ensure the sustainability of human life and the conservation of Galapagos species, it is essential to know the terrestrial biodiversity and the interactions with socio-ecological systems. To fill this information gap, a baseline of insects was established on 40 farms on Santa Cruz Island. Transects were set up to carry out foliage sweeps with entomological nets and manual collections of insects in the crops of each farm. A total of 16,533 individuals were collected and identified at different taxonomic levels, 10,331 were identified at the species level. 135 species of insects were identified, of which 18.7 % corresponded to endemic, 13.3 % to native, and 46.7 % to introduced species. The species: Bromeloecia wolverinei, Ceraeochrysa everes, Coproica bisphanta, Cosmosciara hartii, Dettopsomyia formosa, Pseudolycoriella cavatica, Psychoda alternata, Pullimosina heteroneura, Zagrammosoma lineaticeps are new records for Galapagos. This information is a useful tool to incorporate into sustainable agricultural practices. For this reason, it is recommended to strengthen the entomological survey system and technical support in the agricultural area of Santa Cruz.La producciĂłn agrĂ­cola en las GalĂĄpagos empezĂł a principios del siglo XX en las cuatro islas habitadas. Actualmente, se conoce muy poco acerca del nĂșmero, abundancia y distribuciĂłn de especies de insectos y plantas en el ĂĄrea agropecuaria. La informaciĂłn sobre la presencia de especies invasoras y sus impactos en la producciĂłn agrĂ­cola tambiĂ©n es escasa. Para asegurar la sostenibilidad de la vida humana y la conservaciĂłn de las especies de las GalĂĄpagos, es fundamental conocer esta biodiversidad terrestre y las interacciones con los sistemas socio-ecolĂłgicos. Con el propĂłsito de llenar esta brecha de informaciĂłn, se levantĂł una lĂ­nea base de insectos en 40 fincas de la Isla Santa Cruz. Para esto, se establecieron transectos en los que se realizaron barridos del follaje con redes entomolĂłgicas y colectas manuales de insectos en los cultivos de cada finca. Se colectaron e identificaron a diferentes niveles taxonĂłmicos 16 533 individuos y de estos, 10 331 fueron identificados a nivel de especie. Se identificaron 135 especies de insectos, de estas el 18,7 % corresponde a insectos endĂ©micos, el 13,3 % a nativos, y el 46,7 % a introducidos. Las especies: Bromeloecia wolverinei, Ceraeochrysa everes, Coproica bisphanta, Cosmosciara hartii, Dettopsomyia formosa, Pseudolycoriella cavatica, Psychoda alternata, Pullimosina heteroneura, Zagrammosoma lineaticeps son nuevos registros para GalĂĄpagos. Esta informaciĂłn constituye una herramienta Ăștil a la hora de incorporar prĂĄcticas agrĂ­colas sostenibles. Por esto, se recomienda reforzar el sistema de vigilancia entomolĂłgica y acompañamiento tĂ©cnico en la zona agropecuaria de Santa Cruz

    Preventing Establishment: An Inventory of Introduced Plants in Puerto Villamil, Isabela Island, Galapagos

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    As part of an island-wide project to identify and eradicate potentially invasive plant species before they become established, a program of inventories is being carried out in the urban and agricultural zones of the four inhabited islands in Galapagos. This study reports the results of the inventory from Puerto Villamil, a coastal village representing the urban zone of Isabela Island. We visited all 1193 village properties to record the presence of the introduced plants. In addition, information was collected from half of the properties to determine evidence for potential invasiveness of the plant species. We recorded 261 vascular taxa, 13 of which were new records for Galapagos. Most of the species were intentionally grown (cultivated) (73.3%) and used principally as ornamentals. The most frequent taxa we encountered were Cocos nucifera (coconut tree) (22.1%) as a cultivated plant and Paspalum vaginatum (salt water couch) (13.2%) as a non cultivated plant. In addition 39 taxa were naturalized. On the basis of the invasiveness study, we recommend five species for eradication (Abutilon dianthum, Datura inoxia, Datura metel, Senna alata and Solanum capsicoides), one species for hybridization studies (Opuntia ficus-indica) and three species for control (Furcraea hexapetala, Leucaena leucocephala and Paspalum vaginatum)

    Land use management in the Galapagos: A preliminary study on reducing the impacts of invasive plant species through sustainable agriculture and payment for ecosystem services

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    Terrestrial invasive species have been identified as one of the largest threats to endemic plants and wildlife in Galapagos, and their spread remains one of the biggest challenges for the region. The management of these species is a common link among all land‐use activities, and impacts all residents as economic activities in Galapagos are linked to its status as a unique landscape. The study aims, through the use of key informant interviews, policy documents and literature, to provide new insights into plant invasive species management by exploring two land‐use interventions—and the associated challenges and opportunities—currently being proposed by policymakers, academics, and other relevant actors. These are (a) local sustainable agricultural production and (b) policies and mechanisms, specifically the ‘Buen vivir’ paradigm with/and payments for ecosystem services. It explores how these can create bridges and be beneficial to both conservation and development. However, although the initiatives offer real opportunities to manage and control invasive species, challenges remain in the form of how these activities will be carried out and by whom. Findings show that probable success is dependent on community inclusion with coordinated and integrated approaches from robust institutions with connectivity among land‐use actors/managers. In addition, support is needed for organisations/stakeholders that are currently tackling the invasive species issue. Studies on land use remain crucial as relatively contained and pristine landscapes such as Galapagos are likely to be increasingly important as a means to detect human‐induced alterations at the frontiers of ecology

    Tectonic evolution of the Rehamna metamorphic dome (Morocco) in the context of the Alleghanian-Variscan orogeny

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    Structural and 40Ar/39Ar geochronological investigations of the Rehamna Massif (Meseta, Moroccan Variscan belt) provide new constraints on the tectonic evolution of the Alleghanian-Variscan orogen during the Upper Paleozoic. Three main tectonic events have been recognized: (1) Southward thrusting of an Ordovician sequence over the Proterozoic basement, its Cambrian sedimentary cover, and the overlying Devono-Carboniferous basin. This event caused subhorizontal shearing and prograde Barrovian metamorphism of the buried rocks. (2) Continuous shortening resulting in the development of a synconvergent extrusion of metamorphosed units to form a dome elongated E-W. This was responsible for synconvergent detachment of the Ordovician upper crustal sequence. The timing of these two episodes is constrained to 310–295 Ma by cooling and metamorphic amphibole and mica ages (3) A NW-WNW convergence in a direction orthogonal to the previous one and characterized by the accretion of the Rehamna dome to the continental basement in the east. Based on 40Ar/39Ar cooling ages from a syntectonic granitoid and its host rocks and metamorphic 40Ar/39Ar ages from greenschist facies mylonite, the timing of this event falls between 295 and 280 Ma. The end of the Variscan orogeny in the Moroccan Meseta is constrained by the 40Ar/39Ar cooling age of a posttectonic pluton dated at ~275 Ma. The tectonic events highlighted in Morocco coincide with the late Variscan-Alleghanian tectonic evolution of southern Europe and North America and can be correlated with the global reorganization of plates that accompanied suturing of Pangaea at around 295 Ma.Peer reviewe

    Les conditions de la contestation d'un décompte général

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    « Code de la commande publique : pour une approche économique assumée, modernisée et enrichie »

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    International audienceLes codifications rĂ©centes vont au-delĂ  de l’objectif de valeur constitutionnelle d’accessibilitĂ© et d’intelligibilitĂ© de la loi et font gĂ©nĂ©ralement apparaĂźtre une marque de fabrique, une singularitĂ© qui est aussi une justification du code concernĂ© (par ex. le dialogue dans le CRPA). Cette ambition spĂ©cifique du code de la commande publique repose sur la volontĂ© de renforcer l’efficacitĂ© Ă©conomique de ces contrats. Cette derniĂšre apparait Ă  travers un triple objectif : mieux assumer la nature Ă©conomique des contrats de la commande publique, moderniser l’articulation entre commande publique et politique publique et enfin, enrichir la rationalitĂ© Ă©conomique des dĂ©cisions prises, spĂ©cialement en donnant la place qu’elle mĂ©rite Ă  l’exĂ©cution des contrat

    "Le recours des tiers en contestation de la validité du contrat administratif, une espÚce invasive au génome maßtrisé"

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    Cette longue contribution (120.000 signes, 31 pages) parue dans un numĂ©ro spĂ©cial hors-sĂ©rie de la revue ComplĂ©ment Commande Publique (Les dossiers Commande publique), est consacrĂ©e Ă  la dĂ©cision du CE AssemblĂ©e 4 avril 2014, DĂ©partement du Tarn-et-Garonne, req. n° 358994, Lebon.La premiĂšre partie permet d’établir que la dĂ©cision « Tarn-et-Garonne » est ambitieuse puisqu’elle Ă©largit Ă  de nouvelles catĂ©gories de tiers, le champ du recours en contestation de la validitĂ© des contrats rĂ©servĂ© jusqu’alors aux parties, aux concurrents Ă©vincĂ©s et au reprĂ©sentant de l’Etat chargĂ© du contrĂŽle de lĂ©galitĂ©. La dĂ©cision est mise en perspective avec les autres jurisprudences clĂ©s du contentieux contractuel, ce qui permet de dĂ©montrer la nature d’espĂšce invasive de ce recours en contestation de la validitĂ© du contrat dont l’impact sur les recours existants – il y a absorption, destruction ou cohabitation – doit ĂȘtre quantifiĂ© afin de dresser un portrait de la nouvelle architecture contentieuse qui en rĂ©sulte. Dans la seconde partie, il est dĂ©montrĂ© que la dĂ©cision « Tarn-et-Garonne » est Ă©galement mesurĂ©e. En effet, le gĂ©nome du nouveau recours est maĂźtrisĂ© par le Conseil d’Etat qui peut ainsi Ă©viter une fragilisation excessive des contrats administratifs, en jouant sur ses conditions de recevabilitĂ©, en posant des limites quant aux moyens opĂ©rants et en imposant au juge de prendre la mesure strictement nĂ©cessaire et proportionnĂ©e Ă  la situation.PLAN : Introduction : « 2007/2014. Sept ans de rĂ©flexion et d’action pour rĂ©nover totalement le contentieux des contrats administratifs ». PremiĂšre partie – « Une espĂšce invasive ». L’invasion du contentieux des contrats administratifs par l’espĂšce d’apparition rĂ©cente que constitue le recours en contestation de la validitĂ© a, sur les espĂšces endĂ©miques, des effets variables. D’abord, le nouveau recours apparaĂźt largement comme la mutation de recours en contestation de la validitĂ© du contrat existants. Il les absorbe, les remplace par une curieuse mutation dont il faudra dĂ©terminer si elle conserve des traits des recours initiaux (1.1- « L’invasion-absorption : la fusion avec des recours existants » - 1.1.1- « La mutation des recours existants » / 1.1.2- « La transmission de certains caractĂšres antĂ©rieurs ? »). Ensuite, le nouveau recours bouscule le recours pour excĂšs de pouvoir qu’il fait disparaĂźtre partiellement (1.2- « L’invasion-destruction : la substitution Ă  certains recours pour excĂšs de pouvoir », avec 1.2.1- « Le sort scellĂ© du recours pour excĂšs de pouvoir contre trois actes indivisibles du contrat » / 1.2.2- « Le sort en suspens des actes non-indivisibles et des actes pĂ©riphĂ©riques »), tout en parvenant Ă  cohabiter avec lui dans certains cas rĂ©siduels (1.3- « L’invasion-cohabitation : la survie de certains recours pour excĂšs de pouvoir », avec 1.3.1- « Les clauses rĂ©glementaires » / 1.3.2- « Les actes administratifs dĂ©tachables de contrats de droit privĂ© »).Seconde partie – « Un gĂ©nome maĂźtrisĂ© ». En manipulant le patrimoine gĂ©nĂ©tique du recours lui-mĂȘme, le Conseil d’Etat tente d’éviter le double Ă©cueil de la fragilisation des contrats administratifs et de la complication de la structure de leur contentieux. La prolifĂ©ration des recours est contenue par de strictes conditions de recevabilitĂ© (2.1- « La recevabilitĂ© : la prolifĂ©ration des recours contenue », avec 2.1.1- « La condition de recevabilitĂ© relative aux requĂ©rants » / 2.1.2- « Les autres conditions de recevabilitĂ© ») et l’éparpillement de la discussion par des limites posĂ©es quant aux moyens opĂ©rants (2.2- « Les moyens : l’éparpillement de la discussion limitĂ© », avec 2.2.1- « Les tiers privilĂ©giĂ©s » / 2.2.2- « La gĂ©nĂ©ralitĂ© des tiers »). L’équilibre toujours recherchĂ© entre lĂ©galitĂ© et stabilitĂ© des actes juridiques est confiĂ© au juge administratif qui dispose d’une plĂ©nitude de juridiction lui permettant de prendre, dans chaque cas, la mesure strictement nĂ©cessaire et proportionnĂ©e Ă  la situation (2.3- « Les pouvoirs : la condamnation du contrat encadrĂ©e », avec 2.3.1- « La survie du contrat plutĂŽt que son anĂ©antissement » / 2.3.2- « La rĂ©siliation plutĂŽt que l’annulation » / 2.3.3- « Les autres pouvoirs »
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