Ecological Economics 25 (1998) 323 – 346 ANALYSIS Use of environmental functions to communicate the values of a mangrove ecosystem under different management regimes Alison J. Gilbert *, Ron Janssen Institute for Enironmental Studies, Vrije Uniersiteit, De Boelelaan 1115, 1081 HV Amsterdam, The Netherlands Received 25 August 1996; received in revised form 17 April 1997; accepted 25 April 1997 Abstract Mangroves are part of rich ecosystems providing a variety of environmental goods and services. Underestimation of their value and of the impacts of human activities is a major factor contributing to the widespread loss and degradation of ecosystems. Economists frequently receive the blame for such environmental ills, but it can also be argued that ecologists communicate inadequately their knowledge to decision makers and therefore have limited influence. This article links information supplied by ecologists to the information required for effective and efficient mangrove management. A key problem which ecologists face is the high degree of interconnectedness within and between ecosystems. This makes it difficult to predict what is going to happen, let alone understand what is going on. The concept of ‘environmental function’ is used in combination with system diagrams to address this problem. System diagrams are used to identify and assess goods and services produced by the system under different management regimes. These goods and services are then valued to enable assessment of the economic efficiency of the management regimes. © 1998 Elsevier Science B.V. All rights reserved. Keywords: Mangrove management; Environmental functions; Valuation; Sustainability 1. Introduction Mangroves are salt-tolerant trees or shrubs found along low-energy, tidal shorelines between latitudes in tropical and subtropical areas (ap- proximately between 30°N and 30°S). They colonise newly formed tidal flats in the wind and wave shadows of promontories and islands, and behind wave-absorbing sand bars and seagrass beds (Carter, 1988). As much as 75% of low-lying tropical coastlines with freshwater drainage sup- port mangrove ecosystems (WRI and IUCN, 1986). Mangroves provide the basis for complex * Corresponding author. Tel.: +31 20 4449555; fax: +31 20 4449553; e-mail: alison.gilbert@ivm.vu.nl 0921-8009/98/$19.00 © 1998 Elsevier Science B.V. All rights reserved. PII S0921-8009(97)00064-5