Physical, chemical, and management-related drivers of submerged macrophyte occurrence in Mediterranean farm ponds

The construction of ponds for irrigation has proliferated during last decades in Mediterranean regions. If properly constructed and managed, ponds may simultaneously meet conservation and agricultural objectives: the preservation of certain macrophytes might improve water quality for irrigation purposes. However, the effects of management are often neglected when analyzing the main drivers of organisms community structure. Here we investigated the effect of environmental variables, construction type and management practices on the occurrence of submerged macrophytes (vascular plants, charophytes, filamentous algae). Total submerged macrophyte coverage and richness did not vary with pond type, but the presence of submerged macrophytes was significantly higher in embankment ponds. Artificial ponds showed the highest charophyte richness but lowest vascular plant occurrence. Total submerged macrophyte occurrence mainly correlated with conductivity and littoral vegetation, whilst the relative importance of environmental factors was higher than variables related to pond type and management. However, embankment ponds showed the highest richness of vascular plants and filamentous algae, and artificial ponds contributed to the regional pool of charophyte species. Thus, construction pond type and management levels might be relevant to understand submerged macrophytes occurrence in man-made ponds, since the three pond types contributed to the local and regional species pool.