Fill
A. R. MAIN
never halophytic. These obrJervations suggeRt that Neobatrachua species
are able to tolerate, aa larvae, some degree of salinity in the water.
Immediately after rain, when species of Neobatrachw breed, all waters
are fresh. However, as ponds dry out the salinity rises and healthy late
stage larvae of N . uqlamorei, N. centralis anti N . &or have been seen to
survive in water while the salinity rose from 8*4%,, to 10-50/, in a week.
A t this stage the frog larvae were eating orustacea such aa Triops
awtraliewk Larvae of Cycloranct and Limnodynastes have only been
found in fresh water. No laboratory experiments on salt tolerance have
been done, but the field observations suggest that the limit of distribution of Cyclorana and Limnodynastes spenceri may be related to their
inability to tolerate the saline conditions which are common to the
south of their range.
2. Habitat preference
A sowewhat similar case is provided by the species Pseuhphryne
guenthera and P . midentalis. The principal part of the range of each
species i s determined by the Beason of rainfall. However, there is an
area of overlap where the two species may be found in the same region
and, unless the area has been disturbed by settlement, the species never
occur togather. The water preferred by P . guenthri is neutral in pH
and usually clear; that by P. occidentalis is alkaline (pH 8-9) and usually
cloudy. In the zone of overlap the first of these dissimilar breeding conditions is found on granite tors which occur throughout the area, and the
second in swamps in which the vegetation is dominated by Melaleuxu sp.
Straughan and Main (1966) showed that C. tinnula Straughan and
Main was confined to acid paper-bark (Melaleuca) swamps of the
“wallurn” in southern Queensland where it bred in water with a range
of pH from 4.3 to 5.2. Crinia signifera Girard and C. parinsignifera
Main which occur in the same geographical region breed in water with
a range of pH from 4.7 to 6.3 and 4.9 to 7.0 respectively.
A somewhat different situation is provided where the physical nature
of the soil appears to determine the species of frog which occurs, for
example, in summer rainfall areas Notaden burrows in sandy areas
away from water courses, while Cyclorana spp. burrows in clay. In
southern regions where Heleiopow and Neobatmhw species occur, the
former we aesooiated with sandy soils and the latter with clay (Bentley
et al., 1958; Main et al., 1950). In all such cases distribution is governed
by what may be considered minor habitats.
A somewhat analogous situation is that of Crlnia glauerti which
occupies permanently wet situations such a8 sloughs while Crinicc
insignifera, C. psedinsignifera and C. subinsignifera are restricted to
swamp8 which hold water only during the winter. Of the laat three
A. R. MAIN
never halophytic. These obrJervations suggeRt that Neobatrachua species
are able to tolerate, aa larvae, some degree of salinity in the water.
Immediately after rain, when species of Neobatrachw breed, all waters
are fresh. However, as ponds dry out the salinity rises and healthy late
stage larvae of N . uqlamorei, N. centralis anti N . &or have been seen to
survive in water while the salinity rose from 8*4%,, to 10-50/, in a week.
A t this stage the frog larvae were eating orustacea such aa Triops
awtraliewk Larvae of Cycloranct and Limnodynastes have only been
found in fresh water. No laboratory experiments on salt tolerance have
been done, but the field observations suggest that the limit of distribution of Cyclorana and Limnodynastes spenceri may be related to their
inability to tolerate the saline conditions which are common to the
south of their range.
2. Habitat preference
A sowewhat similar case is provided by the species Pseuhphryne
guenthera and P . midentalis. The principal part of the range of each
species i s determined by the Beason of rainfall. However, there is an
area of overlap where the two species may be found in the same region
and, unless the area has been disturbed by settlement, the species never
occur togather. The water preferred by P . guenthri is neutral in pH
and usually clear; that by P. occidentalis is alkaline (pH 8-9) and usually
cloudy. In the zone of overlap the first of these dissimilar breeding conditions is found on granite tors which occur throughout the area, and the
second in swamps in which the vegetation is dominated by Melaleuxu sp.
Straughan and Main (1966) showed that C. tinnula Straughan and
Main was confined to acid paper-bark (Melaleuca) swamps of the
“wallurn” in southern Queensland where it bred in water with a range
of pH from 4.3 to 5.2. Crinia signifera Girard and C. parinsignifera
Main which occur in the same geographical region breed in water with
a range of pH from 4.7 to 6.3 and 4.9 to 7.0 respectively.
A somewhat different situation is provided where the physical nature
of the soil appears to determine the species of frog which occurs, for
example, in summer rainfall areas Notaden burrows in sandy areas
away from water courses, while Cyclorana spp. burrows in clay. In
southern regions where Heleiopow and Neobatmhw species occur, the
former we aesooiated with sandy soils and the latter with clay (Bentley
et al., 1958; Main et al., 1950). In all such cases distribution is governed
by what may be considered minor habitats.
A somewhat analogous situation is that of Crlnia glauerti which
occupies permanently wet situations such a8 sloughs while Crinicc
insignifera, C. psedinsignifera and C. subinsignifera are restricted to
swamp8 which hold water only during the winter. Of the laat three