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Juttselg-kärnkonn ehk kõre tehistingimustes kasvatamine ja tasasustamine loodusesse

Pärimets, Kadri (2018) Juttselg-kärnkonn ehk kõre tehistingimustes kasvatamine ja tasasustamine loodusesse. [thesis] [en] The Growing of Epidalea Calamita in Artificial Conditions and Restoring them to the Natuure.

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Abstract

Kõre on väike jässaka kehaga kärnkonn, kelle seljal asub kollane triip. Ta on videviku- ja ööloom, kes saavutab suguküpsuse ligikaudu kolme aastaga. Kudemisel koeb emane 1,5-2 meetri pikkuse kudunööri, mille munarakud isane viljastab. Kõre on väga kitsalt kohastunud liik, kes seab normid ka oma kudemisveekogule. Selleks eelistab ta lamedapõhjalisi, päikesele avatud, taimestiku vaeseid veekogusid, mis on suhteliselt väikesed ja kus veetase ei ületa 30 cm. Sellised on näiteks hästi karjatatud rannaniidud, kus kudemisveekogu püsib avatud ja taimestik veekogu põhjas ja selle ümbruses on madalamurune. Kõre talvitub maa all, keldrites, kiviaedades, jms. kohtades. Talvitumisperiood kestab septembrist-oktoobrist aprillini. Kõre levila ei ulatu Euroopast välja. Paljudes oma levila osades on ta väljasuremisohus. Eestis asuvad kõre elupaigad peamiselt Lääne-Eesti saarestiku ning rannikualal. Ka siin on arvukus aastatega aina kahanenud. Arvukuse languse põhjuseks on enamasti karjatamiskoormuse langusest või karjatamise lõppemisest. Liigi säilimise jaoks on ülioluline jätkata olemasolevate rannaniitude majandamist ning alustada võsastunud ning roostunud rannaniitude osalist taastamist. Selleks, et tagada liigi püsimajäämist tuleb teha toetavat kõre kulleste üleskasvatamist ja taasasustamist loodusesse. Kulleste tehistingimustes üleskasvatamise juures on oluline võimalikult väike suremus, et tagada moonde läbinud isendite suurem arvukus. Selleks on loodud Ohustatud liikide taastamis- ja rehabilitatsioonikeskus Penijõele Matsalu rahvusparki, kus on olemas ruumid ja vahendid kõre tehistingimustes üleskasvatamiseks. Antud töös vaadeldakse lähemalt 2014 - 2017. aastal Kopenhaageni loomaaiast ja Eestimaa eri paikadest toodud kudu ja kulleste tehistingimustes üleskasvatamist ning selle protsessi edukust. Kullesed kasvasid üles väikestes vannides, kuhu oli sisse pandu ka pisut taimestikku. Neile söögiks sai algul antud koerakrõbinaid ning hiljem kalatoitu. Kui kullesed hakkasid moonduma ehk neile tekkisid jalad, pidi nad vannidest välja tõstma ja asetama kastidesse, kuhu oli nelie loodud spetsiaalne 35 keskkond. Juba moondunud konnadele anti toiduks kohapeal kasvatatud hooghännalisi ja äädikakärbsid. Nende viie aasta jooksul taasasustati kokku 22 154 kõret, erinevatesse Eesti kõre elupaikadesse. Antud tegevust, mida viimase viie aasta jooksul on tehtud, võib lugeda edukaks. Sellega seoses on välditud Juttselg-kärnkonna väljasuremist tema elupaikadest Eestis. On tõestatud, et taasasustamise tagajärjel on hakanud toimuma kõrede sigimine ja arvukus on tõusnud. Viimasel viiel aastal on tagatud kõre liigi säilimine ning tuleb ka elupaikade püsimajäämisele rohkem tähelepanu pöörata.

Abstract [en]

The following thesis The growing of Epidalea calamita in artificial conditions and restoring them to the natuure aims to give and overview of the stages of growing Epidalea calamita in artificial conditions, to analyse the success of morphosis and the effect of measured parametres on restoring them to coastal meadows and quarrys. Furthermore, to find out and gather proof if the actions taken help in preserving the species. Epidalea calamita is a small frog with a stocky body, who has a yellow line down the middle of the back. It is a nightlife animal who matures in three years. The female frog lays 1.5-2 metre long string of eggs, which the male will fertilize. Epidalea calamita is very selective about the habitat. They prefer shallow, open and warm ponds with poor vegetation. For example, grazed coastal meadows, where spawning pond stays open and the vegetation stays low in the bottom and around the waterbody. Epidalea calamita hibernates under ground, in basements, stone gardens and other similar places. Hibernation period occurs from September-October until April. The species distribution stays within Europe and is in danger of extinction in many parts of the area. In Estonia the habitats are mainly in the Western Estonia archipelago and coastal areas. The number of population is decrasing in Estonia as well. The reason of that is mostly because of the decrease or ending of grazing. In order to preserve the species, it is essential to continue grazing of the existing coastal meadows and to start restoring the older ones. In 2013 the growing of Epidalea calamita spawn and tadpole from various areas in Estonia started in Penijõe. Centre of recovery of threatened species in Matsalu National Park. Collaboration was also held with the Copenhagen zoo, who provided the centre with spawn and tadpole In order to ensure the survival of the species, support should be given to raise and restore the tadpole to the nature. It is important to minimize the mortality during the raising in artificial conditions. Thus, the number of specimen going through metamorphosis would be higher. In Matsalu National Park the Restoration and Rehabilitation Center for Endagered Species has been created. The centre has 37 specific rooms and instruments for raising Epidalea calamita in artificial conditions. In the present graduation thesis, a closer look is given at the success rate of raising the spawn brought in 2014-2017 from Copenhagen zoo and various places in Estonia. Tadpole was raised in small baths containing a small amount of vegetation. They were first fed with dry dog food, later with fish food. When the metamorphosis started (feet started to develop) the specimen were taken out of the baths and placed into boxes with special environment. The specimen who had gone through methamorphosis, were given Collembola and Drosophila melanogaster (grown on the site) for food. During those five years 22154 specimen of Epidalea calamita were restored to different areas of habitat in Estonia. The actions taken during the recent five years proved to be successful. Therefore, the extinction of Epidalea calamita has been avoided in Estonia. It has been proven that due to restoration of species the number of population is rising. The preservation of the species has been ensured and further attention has to be given to the continuation of the habitats.

Item Type: thesis
Advisor: Oliver Kalda
Subjects: Technoecology > Environmental Protection > Estonian Biota and Biocenosis
Divisions: Institute of Circular Economy and Technology > Environmental Technology and Management
Depositing User: Kadri Pärimets
Date Deposited: 05 Jun 2018 13:08
Last Modified: 27 Aug 2019 08:31
URI: http://eprints.tktk.ee/id/eprint/3814

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