Analysis of earthworms and soil quality in a long-term wetland within an agricultural context

Wetlands represent crucial ecosystems, playing a significant role in maintaining biodiversity and purifying water. This study analysed the biodiversity status of a wetland area used for 30 years for drainage and phytodepuration purposes within the Experimental Agricultural Farm 'L. Toniolo' at the University of Padua. Covering an area of one hectare and having undergone no cultivation over the years, it is characterized by dense woody shrub areas and other herbaceous parts. Semi-natural conditions and conservational features were evaluated using standardized and innovative sampling and analysis methods. Physicochemical, microbiological, and soil fertility parameters were studied, aided by earthworm fauna analysis as a driver for soil conservation. Specifically, the earthworms collected were identified, and their distribution and abundance concerning spatial variations within the area were evaluated. The results revealed a rich diversity of earthworms, with a significant prevalence of endogeic species, particularly abundant in woody-shrub areas. Spatial variation analysis highlighted differences in earthworm community composition among different parts of the wetland, suggesting an association between the distribution of these species and micro-environmental variations. This work highlights the importance of the presence of semi-natural and humid areas, with drainage and phytoremediation purposes or as simple buffer areas, in agricultural contexts as they can act as sites that contribute to the resilience of agricultural territories also through the increase in biodiversity.