342 Intertidal Ecosystems Box Despite the fact that there is no unambiguously accepted list of what is meant by the values of biodiversity, many values are cited as being important Evolutionary value This includes genetic diversity that may allow organisms to persist or change in response to localized threats to diversity This may be very important in intertidal and near-shore coastal habitats, where humans tend to cause most damage to marine habitats Ecological value A naturally functioning habitat with its full complement of biodiversity is necessary for studying and understanding ecological patterns and processes This understanding is, in turn, considered essential for the persistence of life on earth in the face of humanity’s alteration to and degradation of the natural world Economic value There are or may be species of direct economic value On intertidal shores, this includes plants and animals collected or cultured in fisheries, mangrove trees exploited for firewood, and so on Habitats that are used for recreation may also have economic value For example, a wetland with diverse species of birds can have economic value if bird-watchers are prepared to pay to access it Aesthetic value Natural habitats are sometimes perceived to have value simply because they exist This is also sometimes called ‘‘existence value.’’ Ethical value There is argument by many sections of society that all biodiversity has ethical value, that is, we, as human beings, are ethically bound to protect biodiversity This argument comes to the fore when decisions are being made about the rights of humanity to eliminate diseases and other pests from the earth biota, other than the fact that it is variable, unpredictable, and complex Because the species are poorly described and even more poorly understood, it is generally accepted that there is considerable redundancy in the system Therefore, it has been assumed that, if the larger plants are looked after, the small invertebrate animals and the functioning of the habitat will look after itself The same is true of all intertidal habitats Most ecological functions are thought of in terms of general, widespread, and large-scale processes (e.g., the cycling of nutrients throughout a mangrove forest or the maintenance of food webs across a rocky shore) Yet, the fauna and flora that make up most of the diversity and that maintain these ecological functions are variable and patchy and change unpredictably through time, often at very small and localized scales The scales at which ecological structure (the species) and ecological functions (many of the processes) are measured are often quite different It is therefore difficult to relate the stochastic variability that we see in ecological structure with what is often perceived as the predictability in measures of ecological function It is increasingly important that we measure structure and function at a similar range of scales before we will be able to understand the role of natural patchiness in biodiversity in ecology This is not yet widely done, but is crucial if we are to be able to conserve functioning habitats in an increasingly altered world What Services Does Intertidal Biodiversity Provide? Consideration of the relationships between the diversity of species and functioning of ecological systems leads very rapidly to consideration of any ‘‘values’’ of biodiversity Because biodiversity is not well described (i.e., the threats to it are poorly understood and probably variable from place to place and habitat to habitat), there is still considerable controversy about perceived value(s) of biodiversity This is specifically true for most coastal habitats, especially those on temperate coasts, which have not received as much attention from the media and celebrities as have habitats such as coral reefs or tropical rainforests There are many so-called values to biodiversity, some of which are discussed in Box Whatever terms are used, however, they tend to fall into two main categories Ecocentric values are those associated with the well-being of the animals and plants themselves (i.e., they are focused on maintaining the full range of functioning ecological processes) They include such terms as ecological value and evolutionary value (see Box 1) Anthropocentric values, in contrast, are centered on humanity and the role of diversity in maintaining or improving human lifestyles These obviously include a range of values, based on our perceived moral obligations, our ideas of the sort of world that we want to live in, and obvious economic returns from our exploitation of coastal resources In contrast to many terrestrial habitats, nearshore coastal habitats, including nearly all intertidal areas, are generally conserved for anthropocentric values, rather than ecocentric values Following traditions lasting hundreds of years, the sea is still largely regarded as a larder to be plundered rather than a unique set of habitats to be conserved Apart from certain coastal wetlands, which can support large populations of wading birds, most intertidal habitats not abound with large charismatic megafauna Therefore, although they may contain threatened species, these are unlikely to attract media attention Although large areas of mangroves can be extensive, diverse, and very interesting forests, they are still generally valued for their economic returns – provision of firewood, habitats for juvenile commercially exploited fishes, sites for aquaculture, and, unfortunately in many countries, prime real estate for reclamation Similarly, rocky reefs, mudflats, estuaries, and so on are generally considered important for what direct economic value they can provide humanity The loss or degradation of nearshore habitats goes largely unseen because the biota that live in them are small, cryptic, and unknown Yet, they are incredibly diverse and in many parts of the world, make up a large amount of the endemic fauna and flora Most of these organisms not have commercial value As long as these coastal habitats continue to be considered valuable mainly with respect to the direct economic services that they provide to humankind, there will be little initiative to carry out the research and impose the necessary management to conserve this diversity Conclusions The management of biodiversity in intertidal coastal habits needs a different approach from that used in terrestrial habitats Except for species that are considered to play a key role in local ecological processes, it is unlikely to be useful to attempt