Abstract

Ecosystem-based management (EBM) is an appropriate approach for coastal lagoons and estuaries with high habitat heterogeneity and coupled gradients. From the standpoint of temporal and spatial scales and functional integration, we conclude that the drainage basin with respect to the continuum ‘low river basin-wetlands-delta-coastal lagoon-estuary-estuarine plume on the sea shelf’ is the optimal ecosystem level for a successful EBM approach to coastal lagoons and estuaries as biocomplex systems. Because EBM is a tool for social and economic development, any such EBM programme should: a) reduce those market distortions that affect biological diversity, b) align incentives to promote biodiversity conservation and sustainable use, c) internalise costs and benefits in the ecosystem to the extent feasible, d) understand the habitat gradients concept in the coastal zone and how they apply to the EBM approach, and d) keep in mind that only management based on ecosystem integrity and functioning is sustainable.

Introduction

Coastal lagoons and estuaries are highly productive, highly vulnerable and, particularly for tropical coasts, highly diverse with respect to both species and habitats. These ecosystems support many valuable populations of fish and shellfish as well as birds and macrophytes. At the same time, a high proportion of the world's human population lives close to coastal lagoons and estuaries, which are therefore the recipients of many kinds of contaminants. The Caribbean region has an area of 15 million km2, in which 1.9 million km2 correspond to the continental shelf, with three main large marine ecosystems (LME); the Gulf of Mexico, the Caribbean Sea and the North Brazil Shelf. The coastal oceanography is complex due to the interactions between the Caribbean current, tropical hurricanes and the strong influence of major rivers such as the Amazon (200,000 m3/s), the Orinoco (35,000 m3/s), the Magdalena (7,800 m3/s), the Rio Dulce (1,100 m3/s), the Grijalva-Usumacinta (4,700 m3/s) and the Mississippi (19,000 m3/s). Deltaic systems, mangroves and integration of the LME with coastal zone management are a key concern for EBM of coastal lagoons and estuaries (Yáñez-Arancibia 2005; Yáñez-Arancibia and Day 2004a, 2004b; Day et al.