98 research outputs found

    Bioinspired Breathable Architecture for Water Harvesting

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    Thuja plicata is a coniferous tree which displays remarkable water channelling properties. In this article, an easily fabricated mesh inspired by the hierarchical macro surface structure of Thuja plicata branchlets is described which emulates this efficient water collection behaviour. The key parameters are shown to be the pore size, pore angle, mesh rotation, tilt angle (branch droop) and layering (branch overlap). Envisaged societal applications include water harvesting and low cost breathable architecture for developing countries

    Reproductive Ecology and Severe Pollen Limitation in the Polychromic Tundra Plant, Parrya nudicaulis (Brassicaceae)

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    Pollen limitation is predicted to be particularly severe in tundra habitats. Numerous reproductive patterns associated with alpine and arctic species, particularly mechanisms associated with reproductive assurance, are suggested to be driven by high levels of pollen limitation. We studied the reproductive ecology of Parrya nudicaulis, a species with relatively large sexual reproductive investment and a wide range of floral pigmentation, in tundra habitats in interior montane Alaska to estimate the degree of pollen limitation. The plants are self-compatible and strongly protandrous, setting almost no seed in the absence of pollinators. Supplemental hand pollinations within pollinator exclusion cages indicated no cage effect on seed production. Floral visitation rates were low in both years of study and particularly infrequent in 2010. A diversity of insects visited P. nudicaulis, though syrphid and muscid flies composed the majority of all visits. Pollen-ovule ratios and levels of heterozygosity are consistent with a mixed mating system. Pollen limitation was severe; hand pollinations increased seed production per plant five-fold. Seed-to-ovule ratios remained low following hand pollinations, indicating resource limitation is likely to also be responsible for curtailing seed set. We suggest that pollen limitation in P. nudicaulis may be the result of selection favoring an overproduction of ovules as a bet-hedging strategy in this environmental context of highly variable pollen receipt

    Ranking species in mutualistic networks

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    Understanding the architectural subtleties of ecological networks, believed to confer them enhanced stability and robustness, is a subject of outmost relevance. Mutualistic interactions have been profusely studied and their corresponding bipartite networks, such as plant-pollinator networks, have been reported to exhibit a characteristic “nested” structure. Assessing the importance of any given species in mutualistic networks is a key task when evaluating extinction risks and possible cascade effects. Inspired in a recently introduced algorithm –similar in spirit to Google's PageRank but with a built-in non-linearity– here we propose a method which –by exploiting their nested architecture– allows us to derive a sound ranking of species importance in mutualistic networks. This method clearly outperforms other existing ranking schemes and can become very useful for ecosystem management and biodiversity preservation, where decisions on what aspects of ecosystems to explicitly protect need to be made

    From Sea to Sea: Canada's Three Oceans of Biodiversity

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    Evaluating and understanding biodiversity in marine ecosystems are both necessary and challenging for conservation. This paper compiles and summarizes current knowledge of the diversity of marine taxa in Canada's three oceans while recognizing that this compilation is incomplete and will change in the future. That Canada has the longest coastline in the world and incorporates distinctly different biogeographic provinces and ecoregions (e.g., temperate through ice-covered areas) constrains this analysis. The taxonomic groups presented here include microbes, phytoplankton, macroalgae, zooplankton, benthic infauna, fishes, and marine mammals. The minimum number of species or taxa compiled here is 15,988 for the three Canadian oceans. However, this number clearly underestimates in several ways the total number of taxa present. First, there are significant gaps in the published literature. Second, the diversity of many habitats has not been compiled for all taxonomic groups (e.g., intertidal rocky shores, deep sea), and data compilations are based on short-term, directed research programs or longer-term monitoring activities with limited spatial resolution. Third, the biodiversity of large organisms is well known, but this is not true of smaller organisms. Finally, the greatest constraint on this summary is the willingness and capacity of those who collected the data to make it available to those interested in biodiversity meta-analyses. Confirmation of identities and intercomparison of studies are also constrained by the disturbing rate of decline in the number of taxonomists and systematists specializing on marine taxa in Canada. This decline is mostly the result of retirements of current specialists and to a lack of training and employment opportunities for new ones. Considering the difficulties encountered in compiling an overview of biogeographic data and the diversity of species or taxa in Canada's three oceans, this synthesis is intended to serve as a biodiversity baseline for a new program on marine biodiversity, the Canadian Healthy Ocean Network. A major effort needs to be undertaken to establish a complete baseline of Canadian marine biodiversity of all taxonomic groups, especially if we are to understand and conserve this part of Canada's natural heritage

    neomexicana

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    Packera neomexicana (A. Gray) W.A. Weber & Á. Löve var. neomexicanaPurgatory Camp Ground, about 28 miles north of DurangoGrassy meadow at margin of poplar-spruce forest.Poplar, Spruc

    mutabilis

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    Packera neomexicana (A. Gray) W.A. Weber & Á. Löve var. mutabilis (Greene) W.A. Weber & Á. LöveNew Mexico groundselSenecio mutabilis7.7 miles north of Purgatory Camp Ground.Gravelly site among rocks and scree at margin on spruce forest.Spruc

    multilobata

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    Packera multilobata  (Torr. & A. Gray ex A. Gray) W.A. Weber & A. LöveLobeleaf groundselAlong the Lee Canyon Highway to the Charleston Mts., 2.1 miles northeast of entrance to Toiyabee National Forest.Joshua Trees, Ephedr

    mutabilis

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    Packera neomexicana (A. Gray) W.A. Weber & Á. Löve var. mutabilis (Greene) W.A. Weber & Á. LöveNew Mexico groundselSenecio mutabilis6.6 miles east of Monarch Pass along highway to SalidaLower edge of montane forestca. 9500 feetPopulus tremuloides, Pinus contort

    purshii

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    Astragalus purshii Douglas ex HookerPursh's milk-vetch;woolly-pod milk-vetchAstragalus purshii1.3 miles northwest of Alpine along highway to Swan ValleyIn large one ft. diameter clumps dry ravelly south facing hillEalsamorhiz

    Linum medium (Planch.) Britton

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    https://thekeep.eiu.edu/herbarium_specimens_byname/2612/thumbnail.jp
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