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VOL. 11, ISSUE 4 (2026)
Spatiotemporal dynamics and ecological drivers of freshwater bivalve assemblages in semi-arid tropical waters of India
Authors
Megha O Mulajkar, Raghvendra S Vanjari
Abstract
Freshwater bivalves are filter feeders and
sensitive bioindicators, yet their spatiotemporal community dynamics in
semi-arid tropical inland waters remain poorly quantified. This empirical study
evaluated the seasonal variation, spatial heterogeneity, and physicochemical
drivers of freshwater bivalve assemblages across three distinct freshwater
ecosystems in the state of Maharashtra India viz. Hipparga Reservoir, Jawalgaon
Reservoir, and Bhima River at Machnur. A total of 2,018 individuals belonging
to eight species across two families Unionidae: Lamellidens corrianus,
Lamellidens marginalis, Lamellidens sp. 1, Lamellidens sp. 2, Parreysia
corrugata, Indonaia caerulea; Cyrenidae: Corbicula peninsularis, Corbicula
striatella were reported. They sampled on monthly basis covering Summer,
Monsoon, and Winter seasons. Bivalve community composition was dominated by L.
marginalis (23.24%), L. corrianus (19.82%), and L. sp. 1 (18.73%), while I.
caerulea (2.82%) represented a minor component. Total bivalve abundance exhibited
a marked seasonal peak during Summer (30.08±4.47 ind./sample), driven by
habitat contraction and thermal metabolic stimulation, compared to Monsoon
(27.46±8.21 ind./sample) and Winter (26.54±5.14 ind./sample). Statistically
significant seasonal shifts were observed for Parreysia corrugata (F269=3.832,
p=0.0264), Corbicula striatella (F269=3.323, p=0.0419), and Pielou's
Evenness index J' (F269=4.776, p=0.0114). Inter-site variation was
pronounced for Lamellidens sp. 1 (F269=5.447, p=0.0064) and P. corrugata
(F269=4.882, p=0.0104), linked to substrate differences and
hydrodynamic regimes between lentic reservoirs and lotic riverine habitats.
Ordinary Least Squares (OLS) regression demonstrated that water temperature
(β=-0.0084, p=0.004) and pH (β=0.0322, p=0.021) significantly structured
community evenness (R2=0.233, p=0.0254). Principal Component
Analysis (PCA) identified temperature, dissolved oxygen, turbidity, and
nutrient concentrations (nitrates and phosphates) as primary environmental axes
governing species distribution. These findings provide baseline ecological
thresholds for tropical Unionid and Cyrenid conservation under escalating
climate warming and hydrologic regulation.
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Pages:19-25
How to cite this article:
Megha O Mulajkar, Raghvendra S Vanjari "Spatiotemporal dynamics and ecological drivers of freshwater bivalve assemblages in semi-arid tropical waters of India". International Journal of Fisheries and Aquatic Research, Vol 11, Issue 4, 2026, Pages 19-25
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