Multivariate Analysis of Sites Using Water Invertebrates and Land use as Indicators of the Quality of Biotopes of Mediterranean Relic Plant (Petagnaea gussonei, Apiaceae)

摘要

Petagnaea gussonei is a rhizomatous, perennial scapose hemicryptophyte species belonging to a monospecific genus of Apiaceae. It lives only along woodland rivulets and is a Tertiary relic localized in the restricted area of the Nebrodi Mountains (NE Sicily, Italy). Ecological indicators have been employed to understand the status of eight localities (intermittent rivulets) where the species occurs. In order to evaluate both the rivulets' water-quality and landscape use, index of anthropisation (Ia), water fleas bioassay (TU), and analyses of water macroinvertebrates have been employed. The results obtained for the level of toxicity exclude the presence of macropollutants (TU < 0.001), whereas the analyses of the macroinvertebrates showed the occurrence of several microorganisms typical of altered environments. Correlations of the results about macroinvertebrates with those related to index of anthropisation for each site are positive. Levels of Ia range from 1.29 (minimum anthropisation) to 3.01 (maximum anthropisation), with a mean of 2.41. On the basis of such results, we can confirm the effectiveness of using macroinvertebrates as bioindicators to analyze the status of water together with the other indices used to examine the ecological conditions of the biotopes where the plant occurs.