31 research outputs found
Effect of feeding frequencies on the growth of the European mudminnow larvae (Umbra krameri WALBAUM, 1792) reared in controlled conditions.
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: âGroup Aâ: fed with Artemia salina nauplii four times day-1 and âGroup Bâ: 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: âAâ 15.5 mm, âBâ 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
ĂlĆhely-rekonstrukciĂł lĂĄpi halfajok szĂĄmĂĄra.
A LĂĄpi pĂłc FajvĂ©delmi Mintaprogram cĂ©lja a nemzetközi jelentĆsĂ©gƱ lĂĄpi pĂłc kĂĄrpĂĄt-medencei ĂĄllomĂĄnyĂĄnak megĆrzĂ©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 (âIllĂ©s-tavakâ). Az Ășj vizekben Ă©s a lĂĄpi pĂłc (Umbra krameri) termĂ©szetes Ă©lĆhelyein botanikai, vĂzkĂ©miai, hidrobiolĂłgiai Ă©s halfaunisztikai vizsgĂĄlatokat vĂ©geztĂŒnk. A lĂĄpi pĂłc egykori jelentĆs Ă©lĆhelyein 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 vĂzminĆsĂ©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 âpĂłcosâ vizekre jellemzĆ Ă©rtĂ©keket. A betelepĂtett rĂ©ti csĂkok Ă©s szĂ©les kĂĄrĂĄszok jĂłl fejlĆdtek, ezĂ©rt 2010-2011 folyamĂĄn lĂĄpi pĂłc anyahalakat Ă©s elĆnevelt pĂłcokat telepĂtettĂŒnk az IllĂ©s-tavakba (gĂ©nmegĆrzĂ©s) Ă©s eredeti Ă©lĆhelyĂŒkre. 2010-2011 tavaszĂĄn a szĂ©les kĂĄrĂĄsz Ă©s a lĂĄpi pĂłc sikeresen leĂvott az IllĂ©s-tavakban, a termĂ©szetes pĂłc szaporulat megközelĂtĆleg 1000 db. lĂĄrva volt
Seed longevity and germination characteristics of six fen plant species
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