Contents lists available at ScienceDirect Ecological Indicators journal homepage: www.elsevier.com/locate/ecolind Original Article Economic value of marine biodiversity improvement in coralligenous habitats Stefania Tonin University Iuav of Venice, Santa Croce 1957, 30135 Venice, Italy ARTICLE INFO JEL classification: Q51 (Valuation of Environmental Effects) Q57 (Ecological Economics: Ecosystem Services, Biodiversity Conservation, Bioeconomics, Industrial Ecology) C83 (Survey Methods, Sampling Methods) C35 (Discrete Regression and Qualitative Choice Models, Discrete Regressors, Proportion) Keywords: Coralligenous habitat Marine biodiversity Contingent valuation method Knowledge and attitude Protest responses ABSTRACT Coralligenous habitats are an important ‘hot spot’ of species diversity in the Mediterranean and grant a variety of valuable ecosystem services. Currently, these areas are under threat due to human activities such as un- sustainable and destructive fishing practices, environmental phenomena, and other significant pressures related to global environmental change. The coralligenous habitats are also endangered by practices that result in the presence of abandoned, lost, or otherwise discarded fishing gear (ALDFG) at sea, a worldwide phenomenon only recently stigmatized whose impacts on marine habitats and coralligenous areas are serious. The aim of this paper is to investigate the economic value of restoration strategies promoted to safeguard and improve biodiversity in these coralligenous habitats through a contingent valuation survey administered to a sample of 4000 Italians. Households’ willingness to pay (WTP) for biodiversity restoration and conservation ranges between €10.30 and €64.02 depending on the assumptions underlying the different models. The main positive and significant determinants of WTP are a previous knowledge or familiarity with coralligenous habitats and biodiversity issues, income, education, environmental attitudes, and the knowledge that indiscriminate fishing may be dangerous for biodiversity in a coralligenous habitat. 1. Introduction and motivation Coralligenous habitats constitute one of the most important ‘hot spots’ of species diversity in the Mediterranean (Ballesteros, 2006). These habitats grant a variety of valuable services, commonly called ecosystem services. They provide sheltered areas for young fish, which leads to an increase in fish stocks available to humans; they also have an important role in energy flux and the carbon cycle, and they are one of the preferred diving spots for tourists due to the great diversity of organisms (Ballesteros, 2006). Nowadays, these areas are under threat due to destructive human activities such as over-fishing, pollution, sediment deposition, recrea- tional fishing and trawling, and diving (Ponti, 2001). Other important pressures are related to global environmental changes, leading to mass mortality events and invasions by alien species (Occhipinti-Ambrogi, 2007; Piazzi and Balata, 2009). The coralligenous habitats of the Northern Adriatic, which have been defined as “submarine rocky substrates of biogenic concretions, irregularly scattered in the sandy or muddy sea bed” (Casellato et al., 2007, p 122), are locally called tegnùe. This name was given by the local fishermen, who have known of their existence since the eighteenth century (Olivi, 1792), although they were only truly documented by underwater explorations 50 years ago (Stefanon, 1967). In 2002, an area of tegnùe in the north-west Adriatic, near the city of Chioggia- Venice, was declared Biological Protected Area (Zona di Tutela Biolo- gica – ZTB) and in 2011 it was declared Site of Community Importance (SCI). In these areas, the most significant threat is related to unsustainable fishing practices since they are frequently associated with an increasing quantity of abandoned, lost, or otherwise discarded fishing gear (ALDFG) at sea; the impacts of such practices on marine habitats and coralligenous areas are well documented (Macfadyen et al., 2009). The negative impacts caused by the loss of fishing equipment (e.g. nets, traps, metal tools) on local biodiversity are mainly associated with damage to nursery zones and the unintentional capture of protected species. Even though ALDFG causes considerable damage to the marine environment, estimates of its impact on biodiversity losses in the North Adriatic area are scarce and very little has been done to reduce this problem (www.life-ghost.eu). Moreover, to our knowledge, the eco- nomic value of biodiversity loss caused by ALDFG is not available in the literature, and only some individual examples of the quantitative costs of ALDFG are documented (Macfadyen et al., 2009). The aim of this paper is to investigate the economic value of re- storation strategies promoted to safeguard and improve biodiversity in https://doi.org/10.1016/j.ecolind.2017.11.017 Received 29 July 2017; Received in revised form 7 November 2017; Accepted 8 November 2017 E-mail address: tonin@iuav.it. Ecological Indicators 85 (2018) 1121–1132 1470-160X/ © 2017 Elsevier Ltd. All rights reserved. T