Vol. 35 – 2009 - Ecologia Mediterranea - Université d'Avignon et des ...

Breeding site selection according
to suitability for amphibian larval growth
under various ecological conditions
in the semi-arid zone of northern Israel
Abstract
A series of field monitoring was conducted over
four years on aquatic habitats to test the
hypothesis that breeding habitat selection by six
different amphibian species, belonging to the
Anuran and Urodela orders, was according to
the ecological parameters of the water body,
and not necessarily according to the type of
breeding site. Ecological and biological conditions
of 14 different breeding sites inhabited by
amphibian larvae in northern Israel, including
winter ponds, pits, springs and streams, were
investigated in a region where all six species
exist. The larval growth period was discovered
to vary in different habitats. Most breeding sites
studied had Salamandra infraimmaculata larvae,
although at different periods of the year.
The larvae of Hyla savignyi, Bufo viridis, Rana
bedriagae, Pelobates syriacus and Triturus vittatus
inhabited mostly the winter ponds and pits.
In most cases, the S. infraimmaculata and T. vittatus
larvae were not observed during the same
time period at the same breeding sites. In other
winter ponds, H. savignyi, P. syriacus and T. vittatus
were seen at the same time during the
spring, and along with R. bedriagae in the summer.
Among the various water quality parameters
evaluated at the breeding site, namely, temperature,
pH, soluble oxygen, electrical
conductivity, ammonium (NH 4 ) and invertebrate
biomass, the most influential one was the temperature.
S. infraimmaculata and B. viridis were
detected in ponds with temperatures ranging
about 1.5-24 o C, whereas all other larvae were
observed at temperatures above this range, up
to 34 o C. Based on the results of the investigation,
the major factors affecting the habitat
selected for breeding are the ecological conditions
that allow for survival, growth and metamorphosis
completion of the amphibian larvae.
Keywords: aquatic habitats, Anuran, Urodela,
ecological parameters.
ecologia mediterranea – Vol. 35 – 2009
Tali GOLDBERG 1 , Eviatar NEVO 1 and Gad DEGANI 2
1. Institute of Evolution, Faculty of Sciences and Science Education,
University of Haifa, Haifa 31905, Israel
2. Scientific Director, MIGAL – Galilee Technology Center,
Head of Master Dtudies Dept. of Biotechnology
Faculty of Science and Technology, Academic Tel-Hai College,
Location: South Industry Zone, P.O. Box 831, Kiryat Shimona 11016, Israel,
Fax: +972-4-6944980, Tel: +972-4-695351,
E-mail: gad@migal.co.il
Introduction
Demographic trends in amphibian populations
may be caused by natural fluctuations (Pechmann
et al. 1991), although many studies
imply that the decline in amphibian populations
around the world is due to anthropogenic
factors (Marco 2002a; Marco 2002b;
Semlitsch 2003). Important aspects affecting
amphibian populations are overexploitation,
habitat loss, disease and climatic change (Stuart
et al. 2004). It has also been suggested that
amphibian population declines are the result
of complex interactions among these threatening
stressors, which act synergistically
(Blaustein & Kiesecker 2002; Blaustein &
Johnson 2003; Gardner 2001). The aquatic
phase of the amphibian population is a critical
period in the life history of many amphibian
species. Amphibians breed in different
habitats, including temporary ponds, semipermanent
ponds and in aquatic habitats
where water is available all year round, i.e.,
springs and streams (Degani & Kaplan 1999).
Many factors have an effect on the aquatic
phase of amphibians, and only some of them
have been examined (Degani 1982; Degani
1986; Degani & Kaplan 1999; Degani et al.
2007; Laurila 1998).
The six amphibian species existing in
northern Israel are the striped newt, Triturus
vittatus vittatus; the fire salamander,
Salamandra infraimmaculata (Amphibia,
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