"Both studies underline the sensitivity of the aquatic vegetation of the Albufera to variations in water quality, especially transparency, and that water management, including the quantity and quality of water entering the lagoon, plays a fundamental role in the recovery of submerged macrophytes", says Juan Soria, researcher at the Cavanilles Institute of Biodiversity and Evolutionary Biology (ICBiBE), located in the scientific-academic area of the Science Park of the University of Valencia, which highlights the need to implement continuous monitoring programmes based on remote sensing to assess the effectiveness of ecological restoration measures.
In addition, the also professor of the Department of Microbiology and Ecology of the Faculty of Biological Sciences of the University of Valencia highlights that in particular the Vegetation Index of Normalized Difference (NDVI), an indicator that measures the quantity, quality and development of vegetation by means of sensors installed on a space platform, is an effective methodology for the monitoring of aquatic vegetation in this type of ecosystems.
In particular, the first study, published in the Journal of Marine Science and Engineering (JMSE) focuses on the extraordinary and temporary appearance of Myriophyllum spicatum in spring-summer 2018. The investigation showed that this event coincided with a significant increase in water transparency compared to previous years. However, the vegetation completely disappeared in August 2018, with high summer temperatures as the most important environmental factor. These data could be known from the use of NDVI.
"Both studies underline the sensitivity of the aquatic vegetation of the Albufera to variations in water quality, especially transparency, and that water management, including the quantity and quality of water entering the lagoon, plays a key role in the recovery of submerged macrophytes", Juan Soria, ICBiBE researcher
The second study, published in the journal Water, documents the massive resurgence of marine Najas in the west of the Albufera during the years 2022-2023. It is a species that lives mainly in stagnant and even brackish waters, very sensitive to environmental changes. The results suggest that it was due to a combination of factors such as a reduction in discharges and an increase in water supply from the Júcar river, facilitated by an agreement with the Júcar Hydrographic Confederation.
As in the case of M. spicatum, NDVI proved to be a valuable tool for monitoring the emergence, growth and disappearance of N. marina. Statistical analysis revealed a significant negative correlation between the area covered by N. marina and the total suspended solids concentration (TSS), and a positive correlation with water transparency, measured using the Secchi disk (ZSD), suggesting that greater clarity of water and lower concentrations of suspended solids favor the expansion and density of N. marina.