| Summary: | Sound knowledge on distribution and ecology of imperiled species is an essential
prerequisite for effective conservation planning. Here, we report the distribution and
autecological traits of a newly discovered population of critically-endangered
white-clawed crayfish (Austropotamobius pallipes s. str.) in a small
river in southwestern Germany. Using an established crayfish survey protocol, we detected
white-clawed crayfish in a river stretch of 4.5 km, with an estimated abundance of
1.4 ± 0.2
indiv.·m-2. The sex ratio was even and
sexual maturity was attained at approximately 25 mm carapace length (CL).
Life-history traits, as assessed using Von Bertalanffy’s growth function, indicate a life
history most similar to populations in France, with longevity, asymptotic size, and growth
performance index being higher in males than in females (11 y, 46 mm CL,
and 2.8 and 9 y, 41 mm CL, and 2.7, for males and females, respectively).
Estimated fecundity ranged from 9 to 135 eggs·female-1 (mean: 90 ± 28). White-clawed crayfish were also found in lower reaches of small
tributary streams, of which one also featured endangered stone crayfish
(Austropotamobius torrentium). A syntopic occurrence of both species
was recorded for the first time within a short stretch. Implications for species
conservation are discussed.
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