The annual number of breeding adults and the effective
population size of syntopic newts (
Triturus cristatus
,
T. marmoratus
)

Jehle, R; Arntzen, JW; Burke, TA; Krupa, A; Hodl, W

Abstract

Pond-breeding amphibians are deme-structured organisms with a population genetic
structure particularly susceptible to demographic threats. We estimated the effective
number of breeding adults (
N
b
) and the effective population size (
N
e
) of the European urodele
amphibians
Triturus cristatus
(the crested newt) and
T. marmoratus
(the marbled newt), using
temporal shifts in microsatellite allele frequencies. Eight microsatellite loci isolated from
a
T. cristatus
library were used, five of which proved polymorphic in
T. marmoratus
, albeit
with high frequencies of null alleles at two loci. Three ponds in western France were
sampled, situated 4–10 kilometres apart and inhabited by both species. Parent–offspring
cohort comparisons were used to measure
N
b
; samples collected at time intervals of nine or
12 years, respectively, were used to measure
N
e
. The adult population census size (
N
) was
determined by mark–recapture techniques. With one exception, genetic distances (
F
ST
)
between temporal samples were lower than among populations.
N
b
ranged between 10.6
and 101.8 individuals,
N
e
ranged between 9.6 and 13.4 individuals. For the pond where both
parameters were available,
N
b
/
N
(overall range: 0.10–0.19) was marginally larger than
N
e
/
N
(overall range: 0.09–0.16), which is reflected in the temporal stability of
N
. In line with the
observed differences in reproductive life-histories between the species,
N
b
/
N
ratios for
newts were about one order of magnitude higher than for the anuran amphibian
Bufo bufo
.
Despite of the colonization of the study area by
T. cristatus
only some decades ago, no
significant genetic bottleneck could be detected. Our findings give rise to concerns about
the long-term demographic viability of amphibian populations in situations typical for
European landscapes.

Citation

). Molecular Ecology, 10, 839-850

• Journal Article Type: Article
• Publication Date: Jan 1, 2001
• Deposit Date: Oct 30, 2009
• Journal: Molecular Ecology
• Print ISSN: 0962-1083
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Pages: 839-850
• Keywords: effective number of breeders, effective population size, microsatellites, temporal; method,; Triturus cristatus; ,; Triturus marmoratus
• Publisher URL: http://www3.interscience.wiley.com/journal/117989598/home