Flying above fragility: Remote sensing and field samplings unveil microcrustacean patterns in ephemeral ponds

Temporary ponds (TPs) are ephemeral freshwater habitats that undergo seasonal drying, creating harsh and highly dynamic environments. Microcrustaceans are key biological components of TPs since they play a crucial role in ecosystem dynamics. The main objective of this study is to test an innovative approach that combines field sampling with modern remote sensing technologies to: (i) investigate the temporal variation of microcrustacean communities and the influence of hydroperiod length and pond area in three coastal temporary ponds (TpA, TpB, TpC) and (ii) assess the hydroperiod length using unmanned aerial vehicles (UAVs). Overall, eight microcrustacean families were identified. In TpA, five families were recorded, whereas six families were documented in both TpB and TpC exhibiting diverse feeding strategies. Our observations suggest that the presence and relative abundance of taxa in the ponds significantly changed over time. We observed statistically significant similarities in TpB and TpC communities, with a Jaccard similarity coefficient of 0.833 in January, whereas the comparison between these communities and TpA did not show the same level of similarity. We also found a positive correlation between pond size and Shannon diversity index (Spearman: rho = 0.607, p < 0.01), indicating that an increase in pond area corresponded to greater microcrustacean diversity. Furthermore, our analyses revealed that temporal variability plays a more prominent role than spatial heterogeneity (transect and sub-transect) in explaining the observed biodiversity patterns. Our findings highlight the effectiveness of analyzing temporary environments through a multi-methodological approach that can be replicated over time and internationally adopted.