3,300 research outputs found

    Population connectivity shifts at high frequency within an open-coast marine protected area network.

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    A complete understanding of population connectivity via larval dispersal is of great value to the effective design and management of marine protected areas (MPA). However empirical estimates of larval dispersal distance, self-recruitment, and within season variability of population connectivity patterns and their influence on metapopulation structure remain rare. We used high-resolution otolith microchemistry data from the temperate reef fish Hypsypops rubicundus to explore biweekly, seasonal, and annual connectivity patterns in an open-coast MPA network. The three MPAs, spanning 46 km along the southern California coastline were connected by larval dispersal, but the magnitude and direction of connections reversed between 2008 and 2009. Self-recruitment, i.e. spawning, dispersal, and settlement to the same location, was observed at two locations, one of which is a MPA. Self-recruitment to this MPA ranged from 50-84%; within the entire 60 km study region, self-recruitment accounted for 45% of all individuals settling to study reefs. On biweekly time scales we observed directional variability in alongshore current data and larval dispersal trajectories; if viewed in isolation these data suggest the system behaves as a source-sink metapopulation. However aggregate biweekly data over two years reveal a reef network in which H. rubicundus behaves more like a well-mixed metapopulation. As one of the few empirical studies of population connectivity within a temperate open coast reef network, this work can inform the MPA design process, implementation of ecosystem based management plans, and facilitate conservation decisions

    Vegetation and Flora of the Sand Deposits of the Mississippi River Valley in Northwestern Illinois

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    This study was undertaken to determine vascular plant species composition, vegetation structure, and floristic quality of the major plant communities in the windblown sand deposits of northwestern Illinois during the growing seasons of 2002 through 2005. The major plant communities of the Ayers Sand Prairie Nature Preserve in Carroll County, Big River State Forest in Henderson County, Lost Mound Unit of the Upper Mississippi River Wildlife and Fish Refuge in Carroll and Jo Daviess counties, and the Thomson-Fulton Sand Prairie Nature Preserve located in Whiteside County were examined and the importance values determined for the plant species present. Located on broad terraces of the Mississippi River, these nature preserves and natural areas are remnants of a larger grassland/savanna/forest complex that contained extensive marsh; wet, mesic, and dry sand prairie; sand savanna; and sand forest communities. Most of the sand deposits are now cultivated and the original vegetation is found only in protected remnants, some of which are relatively large. The mature dry sand prairies were dominated by Schizachyrium scoparium; other important species were Opuntia macrorhiza, Dichanthelium villosissimum, Ambrosia psilostachya, and Tephrosia virginiana. Other assemblages of prairie and exotic species were encountered in successional sand prairie communities. Generally, the mature prairie communities in these preserves and natural areas had 35 or more species present in the study plots. Savanna and closed canopy forest communities were also examined. The dry sand savannas were dominated by Quercus velutina and Q. marilandica, dry sand forests were dominated by Q. velutina, and dry-mesic sand forests were dominated by Q. alba and Q. velutina.Illinois Department of Natural Resources; Illinois Nature Preserves Commissionpublished or submitted for publicationis peer reviewe

    Debt Acceleration on Transfer of Mortgaged Property

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    Debt Acceleration on Transfer of Mortgaged Property

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    Environmental and Resource Economics: Some Recent Developments by

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    A first draft of this paper was prepared when the authors were visiting the Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, during April-May 2004. The current version was completed in Colombo, Sri Lanka, in June 2004, while the authors were attending the bi-annual teaching and research workshop of the South Asian Network for Development and Environmental Economics (SANDEE). We are most grateful to K. Sreenivasan (Director of ICTP), and Manik Duggar and Priya Shyamsundar (respectively, Programme Manager and Director of SANDEE), for making our visits both possible and most agreeable. Over the years, we have benefited greatly from discussions with Scott Barrett, William Brock, Stev

    (2807) Proposal to Conserve the Name Acalypha wilkesiana against A. tricolor (Euphorbiaceae)

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    (2807) Acalypha wilkesiana Müll. Arg. in Candolle; Prodr. 15(2):817. Aug (sero) 1866 [Angiosp.: Euphorb.]; nom. cons. prop.Typus: Fiji; [Viti Levu]; Rewa; “Unit. Stat. explor. exped.under Capt. Wilkes” (G-DC barcodes G00324021 &G00324022; isotypi: GH barcode GH00045512; K barcodeK000959008; US Nos. 1944717 & 1944718 [barcodes00096423 & 00096424]). (=) Acalypha tricolor Veitch ex Mast. in Gard. Chron. 1866:483. 26 Mai 1866; nom rej. prop.Neotypus (hic designatus): “Hort. Veitch; New Hebrides[Vanuatu]”; Jul 1844 (K barcode K001235482)

    (2808) Proposal to Reject the Name Acalypha supera (Euphorbiaceae)

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    (2808) Acalypha supera Forssk.; Fl. Aegypt.-Arab.: 162. 1 Oct 1775[Angiosp.: Euphorb.]; nom. utique rej. prop.Typus: non designatus

    Genetic diversity and interdependent crop choices in agriculture

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    The extent of genetic diversity in food crops is important as it affects the risk of attack by pathogens. A drop in diversity increases this risk. Farmers may not take this into account when making crop choices, leading to what from a social perspective is an inadequate level of diversity

    Adam Smith’s Green Thumb and Malthus’ Three Horsemen: Cautionary tales from classical political economy

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    This essay identifies a contradiction between the flourishing interest in the environmental economics of the classical period and a lack of critical parsing of the works of its leading representatives. Its focus is the work of Adam Smith and Thomas Malthus. It offers a critical analysis of their contribution to environmental thought and surveys the work of their contemporary devotees. It scrutinizes Smith's contribution to what Karl Polanyi termed the "economistic fallacy," as well as his defenses of class hierarchy, the "growth imperative" and consumerism. It subjects to critical appraisal Malthus's enthusiasm for private property and the market system, and his opposition to market regulation. While Malthus's principal attraction to ecological economists lies in his having allegedly broadened the scope of economics, and in his narrative of scarcity, this article shows that he, in fact, narrowed the scope of the discipline and conceptualized scarcity in a reified and pseudo-scientific way
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