Breeding, rearing and raising the red-bellied toad Bombina bombina

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Transcript of Breeding, rearing and raising the red-bellied toad Bombina bombina

  • ENDANGERED SPECIES RESEARCHEndang Species Res

    ESR 3: 113, 2004 Published February 3, 2004

    How it all began (Otto Kinne)

    My first encounter with the fire-bellied toad Bom-bina bombina dates back to 1949. Studying at the Uni-versity of Kiel, Germany, I participated in a zoologicalexcursion headed by my academic teacher ProfessorAdolf Remane, an internationally renowned scholar inthe fields of ecology, taxonomy, phylogeny and mor-phology. He was well-known for his profound knowl-edge of local animals and plants.

    The excursion was fascinating. After demonstratingto us students a variety of different life forms in theirnatural habitat, Remane suddenly stopped, placed afinger over his lips and whispered: And now I amgoing to show you something very fine (etwas ganzFeines). Please be as quiet as possible and enjoy withme rare and highly endangered toads animals whichyou will no longer be able to see when you are my age.He tip-toed towards a pond. After reaching it, we stoodaround our teacher and did not see any toad at all.After several minutes of silent waiting, about 25 toadssurfaced one after the other. And yet another 5 minuteslater the males among them began a melodic concertof oop-oop-oop-oops. We listened in awe.

    Some 32 years later, in spring 1981, my wife Helgaand I moved away from Hamburg and bought a housein Oldendorf/Luhe with grounds bordering on the riverLuhe. To my great surprise, during one of my Luhe-valley excursions I observed a fire-bellied toad floating

    on the water surface of a ditch. When I stepped closerit quickly disappeared. I never saw it again.

    It was in 1989 that I decided to assist Bombinabombina in its difficult fight against extinction. Iplanned to breed the toad, to rear and raise offspringand to release juveniles into newly aquired and toad-specifically modified sections of the Luhe valley (Kinneet al. 2003b, Fig. 1). It took about 3 years to build pools,ponds and ditches, over-wintering quarters and fieldlaboratories.

    Where can you get Bombina bombina? They are notfor sale in shops. Any zoo shop that would dare to sellfire-bellied toads risks being fined or closed. And youcannot collect the toad in nature. In Germany, B.bombina are protected by law. It took some efforts tolocate a man who was officially permitted by govern-ment ruling to sell toads raised in his own terrarium orpond to people who can demonstrate the ability tokeep them under adequate conditions. I bought fromhim some adults and received a written purchase doc-ument stamped by a government official. I still keepthat document in a lab drawer.

    After the toads were accomodated in a large terrar-ium with land and water sections, the males began tocall. Older than Professor Remane at the time he pre-dicted the extinction of Bombina bombina, I wasdeeply moved to hear their oop-oop-oop-oop concertagain, and I remained sitting in front of my terrariumfor hours.

    Breeding, rearing and raising the red-bellied toadBombina bombina in the laboratory

    Otto Kinne, Jens Kunert, Waldemar Zimmermann

    Inter-Research and International Ecology Institute Nordbnte 21 & 23, 21385 Oldendorf/Luhe, Germany

    ABSTRACT: We have studied the ecology and biology of the highly endangered ancient amphibianBombina bombina (Linneus 1761) not least in order to encourage scientists, lay people and politi-cians to support this toad in its fight for survival. Hence our report does not strictly adhere to the for-mat of a publication intended solely for scientists. We present here information on breeding, rearingand raising; on the toads ecological requirements; on problems of laboratory maintenance, and onpossibilities of rebuilding extinct wild populations.

    KEY WORDS: Ecology and biology of Bombina bombina Cultivation Production Raising Release

    Resale or republication not permitted without written consent of the publisher

    Inter-Research 2004 www.int-res.com

    *Email: kinne@int-res.com. Fax: +49 4132 8883 First published December 5, 2003, under INTER-RESEARCH REPORTS as Rept 3

  • Endang Species Res: Number 3, 2004

    INTRODUCTION

    The red-bellied toad Bombina bombina (Linneus1761) (German: Rotbauchunke, French: Sonneur ventre de feu) is one of the oldest living forms of life onearth. Within the last decades, the explosive develop-ment of our own species Homo sapiens has made thetoad also one of the most highly endangered forms oflife.

    Not least in central and east Europe many amphib-ians suffer increasingly from changes in their environ-ment that are in essence consequences of human activ-ities. Populations of toads, newts and frogs shrink ordisappear with increasing speed. It is high time tosound a world-wide alarm. We must protect theamphibians and rebuild sufficient numbers and sizesof their habitat areas and thus enhance the amphib-ians chances for surviving human impacts.

    For 10 years we have worked hard to produce theknowledge required for establishing a self sustainingfield population of Bombina bombina. Studies on thetoads ecology and biology provided information on theenvironmental conditions needed for development,reproduction and population survival. Appropriatemoist-meadow land was bought and prepared for serv-ing as a living area for B. bombina: Inter-ResearchLand or IR land (Kinne et al. 2003, Fig.1). IR Landcomprises some 5.5 hectares of the valley of the riverLuhe (North Germany). In IR Land we built pools,ponds and ditches and 2 small field laboratories (Fig. 1)and we demonstrated what can be done in support of

    endangered life by initiatives that do not require muchmoney but much enthusiasm and dedication.

    In contrast, global support of endangered liferequires enormous efforts and most importantly anew concept of ethics: Eco-Ethics* (Kinne 1988, 2002,2003, EEIU Brochures, www.int-res.com).

    MATERIAL

    Taxonomically, Bombina bombina belongs to theAmphibia an animal class comprising the first verte-brates that left the ocean and conquered the land.Amphibians are the ancestors of reptiles, birds andmammals (including our own species Homo sapiens).They evolved from lobe-fin fishes (Crossopterygii) orlungfishes (Dipnoi) more than 400 million years ago.Like B. bombina most amphibians live both in waterand on land (amphi from Greek: both). The majorityof the ca. 4800 living amphibian species (frogs, toads,salamanders, newts, caecilians) are found in the trop-ics. Frogs and toads (Order Anura) form the largestgroup of the Amphibia.

    GENERAL ASPECTS

    Red-bellied toads Bombina bombina have beenrecorded in north and east Europe and in southwestAsia. Published details on their distribution do not suf-ficiently take into account the last few decades inwhich numerous local populations have becomeextinct. The toads live predominantly in (largelypredator-free) low-land meadow areas with plantinhabited small pools, ponds or ditches. They preferclear, non-flowing, calm waters. In the northern val-leys of the river Elbe (Germany) B. bombina spend thewarm season in permanent water bodies (Wilkens1979; see also Engel 1985). In IR Land the toads alsooccupy shallow ground depressions that contain non-permanent water bodies. Overall, the toads habitatsare characterised by unstable environmental condi-tions.

    We hypothesise that such unstable environmentalconditions are not really preferred by Bombina bom-bina but represent refuges from heavy predation(especially by insects, leeches, fishes): B. bombina can

    2

    *Eco-ethics emphasises the significance of healthy ecosys-tems for life on earth. It is represented by the Eco-Ethics In-ternational Union (EEIU) with its rapidly growing numbersof Local Components (Chapters, Youth Groups, TaskForces), Fellows and Members in all parts of the planet(www.eeiu.org), and continually further developed in theUnions publication organ Ethics in Science and Environ-mental Politics (ESEP; www.esep.de).

    Lab 1

    Lab 2

    Office

    1 m

    A/c unit

    Fig. 1. Field laboratories. Floor plan

    http://www.eeiu.orghttp://www.esep.dehttp://www.int-res.com

  • Kinne et al: Breeding Bombina bombina

    live and reproduce perfectly well in the stable, preda-tor-free environments provided in our laboratories andin a field cage. For us B. bombina is an example of a lifeform which nature does not permit to exist under con-ditions that, in terms of its physiological potential,would be optimal. Its low capacity to cope with preda-tion and competition forces the toad to retreat to lesscomfortable conditions which it can tolerate due to itshigh capacity of coping with unstable, rapidly chang-ing environments. Such environments exclude most ofthe toads predators and several of its competitors.Another example of such retreat is the hydroidCordylophora caspia, which has an experimentallydemonstrated salinity optimum of about 15 S (maxi-mum growth and reproductive rates) but lives in verylow salinities in which its major predators cannot exist(Kinne 1956, 1958). A third example is the brine shrimpArtemia salina; it uses the same strategy: retreat toextreme environmental conditions (very high salini-ties) that are lethal to its predators. Accordingly, allthree, B. bombina, C. caspia and A. salina, exist inenvironments they do not like but can tolerate andthus escape their predators. For a comprehensivetreatment on predation and the responses to it by off-shore animals consult Gliwicz (2003).

    As other amphibians of the order Anura (frogs,toads) Bombina bombina copulate with the male ridingon the female, firmly clasping her with his arms (copu-latory embrace or amplexus lumbaris). As soon as thefemale releases eggs, the male distributes sperm overthem and thus initiates fertilisation.

    Statistics. Throughout our work we have avoidedstatistical analyses that would require exposure ofeggs, tadpoles or toad