Abstract
Aim:
The dispersal and geographical range expansion of globally invasive snail Physella
acuta (Draparnaud, 1805) (Gastropoda: Physidae) were little being
monitored following the first report from Kolkata, India. An account of the
encounter of P. acuta in two ponds of North Dinajpur district of West Bengal,
India is recorded here.
Methodology: Multiple samples of freshwater snails were collected
using aquatic nets from the invaded and non-invaded ponds for assessment and
comparison. The shell lengths of the collected P. acuta were measured
using a vernier calliper to represent size class variations of the population
in the ponds.
Results:
Varying numbers of P. acuta were present in the shoreline and the
hydrophytes of littoral zone of invaded ponds. The size class distribution of
P. acuta indicated the establishment of a stable population in the invaded
ponds where a significant difference (P < 0.05) was observed in the
abundance of a native snail Racesina luteola (Lamarck, 1822) when
compared with the abundance in the non-invaded ponds.
Interpretation: Invasion of P. acuta in the ponds
reflected its ability to overcome the predator-borne barriers and to coexist
with the native snails. The geographic range of P. acuta seems to have
extended, even though slower with reference to the first record in India.
Key
words:
Aquatic invasion, Freshwater habitat, Invasive species, Native snail, Physella
acuta
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