31 research outputs found

    Effect of feeding frequencies on the growth of the European mudminnow larvae (Umbra krameri WALBAUM, 1792) reared in controlled conditions.

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    Effects of feeding frequency were examined on European mudminnow larval growth (initial average total body length: 7.5 mm) under controlled rearing conditions. Two treatments were set in 3 replicates: „Group A”: fed with Artemia salina nauplii four times day-1 and “Group B”: fed with Artemia nauplii six times -1 day. At the end of the 21-day-long examination period significant differences (p<0.05) were found in the total length between the two groups. Average final total lengths were the followings in the groups: “A” 15.5 mm, „B” 16.6 mm. Average live weights of the fish in experimental groups reached 34.4±2.4g, and 44.4±1.4g at the end of the trial in groups A and B, respectively. At the end of the trial period larvae were suitable for stocking into natural waters

    ÉlƑhely-rekonstrukció lápi halfajok számára.

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    A LĂĄpi pĂłc FajvĂ©delmi Mintaprogram cĂ©lja a nemzetközi jelentƑsĂ©gƱ lĂĄpi pĂłc kĂĄrpĂĄt-medencei ĂĄllomĂĄnyĂĄnak megƑrzĂ©se Ă©s gyarapĂ­tĂĄsa. 2008-2010 között a Szadai MintaterĂŒlet (Pesti-sĂ­ksĂĄg) degradĂĄlt rĂ©szein 6 db. kubikgödör mĂ©retƱ, egymĂĄstĂłl elszigetelt vĂ­zteret hoztunk lĂ©tre („IllĂ©s-tavak”). Az Ășj vizekben Ă©s a lĂĄpi pĂłc (Umbra krameri) termĂ©szetes Ă©lƑhelyein botanikai, vĂ­zkĂ©miai, hidrobiolĂłgiai Ă©s halfaunisztikai vizsgĂĄlatokat vĂ©geztĂŒnk. A lĂĄpi pĂłc egykori jelentƑs Ă©lƑhelyein az amurgĂ©b terjeszkedĂ©sĂ©t figyeltĂŒk meg. 2009-ben sajĂĄt szaporĂ­tĂĄsĂș rĂ©ti csĂ­kot (Misgurnus fossilis) Ă©s szĂ©les kĂĄrĂĄszt (Carassius carassius) telepĂ­tettĂŒnk az 1. sz. IllĂ©s-tĂłba tĂșlĂ©lĂ©si vizsgĂĄlat cĂ©ljĂĄbĂłl. 2010-2011-ben 26 db. mentett pĂłc anyahalat szaporĂ­tottunk, illetve 660 db. lĂĄrvĂĄt neveltĂŒnk fel. Az 1. sz. IllĂ©s-tĂł fizikai-kĂ©miai vĂ­zminƑsĂ©ge Ă©s a tĂĄplĂĄlĂ©kul szolgĂĄlĂł zooplankton Ă©s makrozoobenton faj- Ă©s egyedszĂĄma kĂ©t Ă©v alatt elĂ©rte a termĂ©szetes „pĂłcos” vizekre jellemzƑ Ă©rtĂ©keket. A betelepĂ­tett rĂ©ti csĂ­kok Ă©s szĂ©les kĂĄrĂĄszok jĂłl fejlƑdtek, ezĂ©rt 2010-2011 folyamĂĄn lĂĄpi pĂłc anyahalakat Ă©s elƑnevelt pĂłcokat telepĂ­tettĂŒnk az IllĂ©s-tavakba (gĂ©nmegƑrzĂ©s) Ă©s eredeti Ă©lƑhelyĂŒkre. 2010-2011 tavaszĂĄn a szĂ©les kĂĄrĂĄsz Ă©s a lĂĄpi pĂłc sikeresen leĂ­vott az IllĂ©s-tavakban, a termĂ©szetes pĂłc szaporulat megközelĂ­tƑleg 1000 db. lĂĄrva volt

    Seed longevity and germination characteristics of six fen plant species

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    Fens are among the most threatened habitats in Europe as their area has decreased considerably in the last centuries. For successful management and restoration conservationists need detailed knowledge about seed bank formation and seed longevity of plants, as these features are closely related to successional and vegetation dynamical processes. I analysed seed longevity and the germination characteristics of six fen plant species by seed burial experiments. Based on seed weight, seed bank was expected for long-term persistent for the light-seeded Schoenus nigricans, Carex appropinquata, C. pseudocyperus, C. davalliana and Peucedanum palustre and also that for the medium-seeded Cicuta virosa. It was proved that, the latter two species have short-term persistent seed banks, while Carex pseudocyperus has a transient seed bank, therefore these species may only have a limited role in restoration from seed banks. It was found that Schoenus nigricans, Carex appropinquata and C. davalliana have persistent seed banks, because some of their four-year-old seeds have emerged. Fresh seeds had low germination rate in all studied species and majority of seeds emerged after winter, except for Carex pseudocyperus. After the germination peak in spring, the majority of the ungerminated seeds of Schoenus nigricans, Peucedanum palustre, Carex appropinquata, C. davalliana and Cicuta virosa entered a secondary dormancy phase that was broken in autumn. I found the seasonal emergence of the latter three species highly similar
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