Environmental Challenges (Dec 2022)
Customizing the Morphological Quality Index (MQI) to evaluate streams in Eastern-Mediterranean ecosystems
Abstract
Geomorphic assessments are crucial to understanding stream processes, defining ecological stream conditions, and improving management and restoration recommendations. This project presents the first systematic geomorphic assessment of a perennial stream in Israel. The Morphological Quality Index (MQI) protocol was applied in 2017–2018 to test its applicability for Eastern-Mediterranean ecosystems, where heavily regulated streams are common, hydrologic variability is high, and no natural reference streams exist due to long-term anthropogenic pressures. Stream segments were analyzed according to the 25 defined MQI metrics and the protocol was customized for local conditions, characterized by a lack of woody species cover. Results showed that the upstream and downstream segments were in very poor and poor condition, respectively. However, most of the stream was in moderate to good condition, and two segments were rated in very good condition. Reduced functionality was found, especially in longitudinal connectivity of sediment and stream flow, with artificiality found in the most upstream and downstream segments. Riparian vegetation was highly degraded along the entire stream, lacking continuity and providing little functionality or ecological services. Bed substrate analyses indicated a lack of typical downstream fining. Previous flood-management efforts modified channel morphology, and ongoing agricultural pressures prevent lateral stream movement. In addition, water extraction in downstream segments and stream-regulation efforts have greatly reduced water flow and natural depositional processes. Combining all the considered elements, the MQI was found to be a highly suitable tool for evaluating Eastern-Mediterranean perennial streams, with modifications recommended based on local management needs.
