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

sented in figure 1 and table 1, respectively.
Larvae were collected and their species identified.
Biotic and abiotic parameters
of the water
Once every two weeks, three water samples
were collected from every water body with a
net (pore size was 450 µm) from a depth of
approximately 10-30 cm. The water volume
that passed through the net was calculated
according to the net’s dimensions and the area
of the water through which the net was
dragged. Zooplankton were counted and identified
using a binocular microscope, and their
numbers assessed from the average of three
samples.
The biomass of invertebrate species in various
aquatic habitats was determined. Following
the identification of the species, a number
of individuals of each species were preserved
in ethanol. By means of an ocular with a graduated
scale, the lengths and widths of every
taxonomical representative were measured (in
scale units which were converted to millimeters).
The computation of the biomass
(Gophen 1976) was carried out by calculating
the volume (according to the equation for a
spherical volume), assuming that the density
of the organism was close to that of water.
The equation for the biomass is:
ecologia mediterranea – Vol. 35 – 2009
Breeding site selection according to suitability for amphibian larval growth
under various ecological conditions in the semi-arid zone of northern Israel
Table 1 – Amphibian larvae breeding sites in this study. Springs = Sp, Streams = St, Pits = Pi, Ponds = Po.
Label Name Type Latitude Longitude Height
(m.a.s.l)
Sp1 Balad spring 157022 236119 446
Sp2 Humema spring 187299 276819 900
Sp3 Navoraya spring 197970 267307 663
St1 Tel-Dan stream 211100 294800 190
Pi1 Maalot pit 176000 267450 596
Pi2 Nimrod pit 216900 295300 760
Po1 Manof pond 172086 250470 340
Po2 Kash pond 196203 270560 809
Po3 Dovev pond 189158 272812 765
Po4 Matityahu pond 192873 274808 665
Po5 Lehavot pond 210150 284300 70
Po6 Sasa pond 186972 270855 810
Po7 Fara pond 193406 274579 676
Po8 Raihaniya pond 195791 272861 665
Water parameters were measured at a depth
of 10 cm every two weeks during the period
in which the pools were filling up. Temperature
and dissolved oxygen data were obtained
by a hand-held oxygen meter (WTW, Oxi330
set, Germany) in situ, and one liter of water
was sampled for the laboratory tests of water
quality, including pH, ammonium concentration,
electrical conductivity (EC) and chlorophyll
a concentration. Water parameters were
analyzed by one-way analysis of variance
(ANOVA), with the level of significance
between groups set at p < 0.05 (ANOVA).
Niche width
The niche breadth for each amphibian larvae
species was characterized according to five
important environmental water variables
(which dramatically differed among the
breeding sites and during the year) – temperature,
conductivity, ammonium, relative oxygen
content (O 2 ) and pH. These determined
the dimensions for a principle component
analysis.
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