Decay and persistence of empty bivalve shells in a temperate riverine system

Area of Science:

• Ecology
• Geology
• Environmental Science

Background:

• Bivalve shells are persistent geological resources for fauna.
• Their role as long-term ecological attributes in riverine systems is understudied.
• Understanding shell decay is crucial for assessing ecosystem functions.

Purpose of the Study:

• To investigate bivalve shell decay rates in riverine systems.
• To assess the influence of environmental factors like river flow and seasonality.
• To compare decay among different bivalve species and sizes.

Main Methods:

• Four bivalve species (Anodonta anatina, Corbicula fluminea, Potomida littoralis, Unio delphinus) were studied.
• Shell decay was monitored in lentic and lotic habitats throughout the year.
• Factors analyzed included species, shell size, river flow, and season.

Main Results:

• Decay rates varied significantly among species, size, flow, and season.
• Thin-shelled species (A. anatina, U. delphinus) decayed faster (3.17%, 2.77% per month) than thick-shelled species (C. fluminea, P. littoralis) (2.02%, 1.83% per month).
• Smaller shells and lotic habitats showed higher decay rates (up to 2.13 times higher).

Conclusions:

• Shell persistence differs significantly among bivalve species, influencing their habitat engineering potential.
• Native species A. anatina and U. delphinus contribute less as habitat engineers than P. littoralis and invasive C. fluminea.
• River flow and seasonality, particularly leaf litter, significantly affect shell decomposition rates.