By G. Carleton Ray

THREE THEMES DOMINATEthis review. The first is similarities, as is apparent within the coastal zone, that is biogeography. Or, as Nelson the biodiversity of which depends on land- in- and Ladiges (1990) put it: "Indeed, what beyond teractions. biogeography is "biodiversity' about?" Second, "Characteristic Biodiversity"--a Static View watershed and seashed patterns and their scale-re- A complete inventory for any biogeo- lated dynamics are major modifiers of biogeo- graphic province on is virtually impossible. graphic pattern. And, third, concepts of biodiver- In fact, species lists, absent a biogeographic frame sity and biogeography are essential guides for of reference, can be ecologically meaningless, be- conservation and management of coastal-marine cause such lists say little about the dynamics of , especially for MACPAs (MArine and environmental change. To address such dynamics, Coastal Protected Areas). biodiversity is best expressed at a of Conservation and conservation bioecology have scales, which this discussion follows. entered into an era of self-awareness of their suc- cesses. Proponents of "biodiversity" have achieved Global Patterns worldwide recognition. Nevertheless: "Like so Hayden el al. (1984) attempted a summary of the many buzz words, biodiversity has many shades of state-of-the-art of global, coastal-marine biogeogra- • . . the coastal zone, meaning and is often used to express vague and phy at the behest of UNESCO's Man and the Bios- which is the most bio- ill-thought-out concepts" (Angel, 1991), as phere Programme (MAB) and the International reflected by various biodiversity "strategies" Union for the Conservation of (IUCN). The diverse portion of (WRI, IUCN, UNEP, 1992; Norse, 1993), wherein overall objective was to review coastal-marine bio- the overall goals are clear, but in which the "game Planet Earth, and geographic provinces, following Udvardy (1975) for plan'" is not. Furthermore, too little attention is the land. Purportedly, the result would enable these within which many given to biodiversity at all levels from genes to to incorporate "representative," marine (Solbrig, 1991), as as to how this and coastal protected areas into a "global network" conservation problems broad spectrum of diversity may be encapsulated of protected areas. A fundamental requirement for most urgently lie. as "the complex mosaic of the variety of forms any classification is that it should be comprehensive on Earth" (Angel, 1991). and comparative. Thus our physical classification This paper focuses on biogeographic pattern at described reasonably symmetrical oceanic and global to subregional scales and on the functional coastal realms (Fig. 1); that is, the oceanic realms dynamics of and ecosystems. are circumferential and the trailing and collision Emphasis is on the coastal zone, which is the most are generally on the east and west sides of biodiverse portion of Planet Earth, and within , respectively. However, the coastal, biotic which many conservation problems most urgently provinces, derived largely from Briggs (1974) (Fig. lie. I will first describe coastal-zone biodiversity 2) cannot be symmetrical, as endemic and from a static point of view, then take up some eco- differ from place to place and, thus, describe logical dynamics, followed by a discussion of con- unique provinces, taxonomically speaking. servation and management implications. Addition- This classification shows that the coastal zone ally, I will submit that the special features of is geomorphologically and ecologically distinct marine and terrestrial systems are subsumed by the from both upland areas and the open sea, follow- ing Ketchum's (1972) definition that the terrestrial portion of the coastal zone includes the continental G. Carleton Ray, Department of Environmental Sci- plains and the seaward portion includes the conti- ences, University of Virginia, Charlottesville, VA 22903, nental shelves. The coastal zone has been con- USA. formed by the rise and fall of from the

50 OCEANOGRAPlfY*VoI.9. No. 1"1996 Fig. 1: A global classification of coastal and marine environments. Oceanic areas are indicated by let- ters. Coastal areas are distinct biogeographically and are shown symbolically as colored bands around the continents. Cross-hatched areas are enclosed . Note the general symmetry of both oceanic and coastal areas. See original text for full explanation. From Hayden et al. (1984); terrestrial biogeographic provinces, after Udvardy (1975).

Pleistocene to present (Fig. 3). With respect to the "characteristic" diversity of and their biodiversity, this zone has disproportionate global species assemblages. This would facilitate descrip- significance. For example, of the approximate tions of what is special about each , as well as 22,000 fish species, about half are restricted to the enable better comparisons among inter alia. • . . it would seem 8% of Planet Earth that is coastal zone, whereas more appropriate to -40% are freshwater and only -10% oceanic (Nel- Watersheds, Seasheds, , and Niche son, 1984), i.e., occurring beyond the continental Subglobally, a biogeographic hierarchy is facil- concentrate on what slope. Other noteworthy coastal-zone species are itated by conceiving the coastal zone as an may be termed the right, bowhead, and gray whales, many polar sea between land and sea, but one that is distinguished birds, seals, walruses, and a host of invertebrates. by strong spatial and temporal gradients, both "characteristic" diversi- Another way to address global biogeographic along and across this zone (Ray and Hayden, , besides biogeographic provinces, is 1992) and within the water column (Holligan and ty of ecoregions and through gradients in . Whether de Boois, 1993). This zone is uniquely where land, their species assem- there is a latitudinal gradient in species richness is sea, and atmosphere intensely meet. Complex in- a of debate (Angel, 1991; Clarke, 1992; teractions produce a hierarchy of mosaics of habi- blages. This would Rohde, 1992; Rex et al., 1993). At the very least, tats, as represented by watersheds, and facilitate descriptions such gradients are heavily dependent; that is, lagoons, , and coastal , within marine mammals, such as seals, are most diverse which the smallest biogeographic scale is that of of what is special in polar regions, whereas fishes are most diverse the species "niche." Thus both physical and bio- about each region, as in the (Ray, 1988). Some taxa have specific logical approaches are necessary to distinguish hi- requirements favoring low temperatures--e.g., erarchical, biogeographic relationships. well as enable better many pinnipeds, cetaceans, and fishes--so that A physical approach is represented by Ray and comparisons among clearly defined gradients in species richness are Hayden (1992), who formulated a simple clas- difficult to evaluate. Comparative biogeographic sification for within-province, coastal-zone struc- regions inter alia. studies at different latitudes are needed to clarify ture for defining "coastal units in which the con- whether biotic patterns result from historical, evo- nections among mass, , and biota across the lutionary, behavioral, or physiological factors, or, coastal zone are stronger than along the , es- in all probability, from combinations among them. pecially those that are associated with fluvial inter- From both points of view, it would seem more actions" (Fig. 4A). These units allow the identi- appropriate to concentrate on what may be termed fication of several fundamental types of watershed

OCEANOGRAPHY'VoI.9, No. 1"1996 5 1 The smallest-scale levels of the biogeographic hierarchy are species-specific and niche. With respect to the former, such habitat types as rocky , , lagoon, various types of ben- thos, etc., appear about equally represented - wide; that is, there appears to be no gradient in coastal-marine habitat diversity from the tropics to the high latitudes. In fact, habitat diversity may in- crease in the polar regions due to the complicating effects of seasons and sea ice. The inference is that ecological complexity and habitat variety are not readily related to and/or resiliency. Pattern and Process--a Dynamic View Little can be said about conservation and man- agement until and unless ecosystem dynamics are incorporated into ecological descriptions. For ex- ample, Steele (1991) has defined functional diver- sity as "the variety of different responses to envi- ronmental change, especially the diverse and scales with which react to each other and to the environment." This approach Fig. 2: A coastal-zone classification for eastern is concordant with the major theme of the North and . Letters indicate phys- IUBS/SCOPE/UNESCO Diversitas program, ical regions: (A) Subpolar; (B) Eastern temper- ate; (C) Eastern Subtropical; and (D) Tropical. Numbers are for biogeographic regions after Briggs (1974); (9) Acadian; (8) Virginian; (7) Carolinian; (6) Louisianian; (5) , and (4) West Indian. Note that the physical and bio- geographic regions reasonably approximate one another. See original text for full explanation. From Hayden et al. (1984).

and receiving basin (coastal seashed) associations (Fig. 4, B and C). This scheme addresses mainly the mesoscale level of and has the property of relating coastal unit size and complex- ity to a variety of processes. Comparisons among types is possible because the units vary in size and dynamics, even though some watersheds may lack certain of the subunits (e.g., rivers in the case of Little can be said some low-lying, tropical islands). The biological approach identifies species as- Fig. 3: Rise and fall in sea level of the coastal about conservation semblages. Ray and Hayden (1993) conducted a zone of United States East and Gulf coasts of dur- and management until principal components analysis of 86 "representa- ing the past several million years. This map shows tive" invertebrate and vertebrate species of the degree to which the storage of water as and unless ecosystem and derived seven, statistically sig- glacial ice affects the position of coastlines. The dynamics are incorpo- nificant, biogeographic assemblages (Fig. 5). All dark blue represents oceanic areas deeper than of these are distinct, although overlapping, and all 130 m that were unaffected by ice vol- rated into ecological are associated with some environmental limiting umes. The mid-blue shows presently submerged factor or factors, such as fronts, bathymetry, and areas that were exposed as subaerial plains dur- descriptions. other conditions. Our analysis was exploratory, ing low stands of the sea that accompanied maxi- but the method has the possibility of defining off- mum advances of Pleistocene ice sheets. The light shore "seasheds" from a biotic point of view. It blue indicates land areas that would be sub- also may be used to define the ecological structure merged if the present continental ice sheets in of large marine ecosystems (LMEs) (Sherman et Greenland and were to melt, thus rais- al., 1993), which have tended to be described by ing sea level by -65 m. The coastal zone roughly factors such as interactions, , approximates the mid-blue and light-blue areas. , and the like. Courtesy Robert Dolan.

52 'VoI.9, No. 1-1996 cP "- ~ - - oEv 2 ---'~



Fig. 4: (A) Structural subdivisions of the coastal zone. Each subdivision is defined by gradients in ecolog- ical processes and attributes. (B) Simple type of coastal in which the flow of water is restricted to tidelands and the shoreface entrainment volume; (C) Complex type of coastal system in which a large drainage system has sufficient flow to bypass the shoreface entrainment volume and drains more or less directly into the offshore volume. Many other combinations are possible due to the sizes, fows, and pres- ence-absence of the structural components. From Ray and Hayden (1992).

which has emphasized that biodiversity may be in- scales represent an hierarchical classification, terpreted in terms of "ecosystem " (Di where the "potential" for species presence is de- Castri and Younbs, 1990; Grassle et al., 1991). pendent on a set of environmental and habitat re- This view is essential for development of scientific quirements defined at those scales. conservation and management strategies. It is among species and their environments at all scales exemplified by dynamic biogeography (e.g., have the potential to influence the ecological rela- The ability of a Hengeveld, 1990), which incorporates time into tionships of the system as a whole. location to provide the management paradigm, applies synoptic ecol- The dynamics of these relationships have been ogy to patterns of distribution, and interrelates explored for the Virginian and Carolinian suitable habitat for a small-scale, local attributes of ecosystems to large- provinces of the Eastern United States by Ray et scale, global ones. al. (in press). The traditionally accepted bound- diversity of species is aries for the Virginian Province are Cape Cod, dependent on an Multiple Biotic Interactions Massachusetts, to Cape Hatteras, North Carolina, The ability of a location to provide suitable and, for the Carolinian Province, Cape Hatteras to array of physical and habitat for a diversity of species is dependent on Cape Canaveral, Florida. At these capes, dramatic biotic factors that an array of physical and biotic factors that vary at changes in coastal characteristics, such as water different temporal and spatial scales. At the largest temperatures and circulation patterns, occur. Major vary at different tem- scale, the limits of a species' range result from differences between these provinces are the sizes, poral and spatial large-scale environmental attributes, such as shapes, and hydrological features of rivers, estuar- water-body characteristics, currents, and . ies, and lagoons, and the relative proportions of scales. Combinations of ranges define biogeographic habitat types, such as beds, soft bottoms, provinces. At smaller scales, each species' distrib- and oyster reefs. All of these features play major ution (i.e., the apportionment of individuals within roles in determining different species assemblages. the range) is constrained by small-scale habitat Our multivariate analysis of estuary-dependent patterns and the species' life-history attributes, as fishes revealed the presence of four large-scale as- is expressed by the concept of niche. It follows semblages for these two provinces: 1) Virginian, that conditions for suitable habitat at different 2) Carolinian, 3) boreal, and 4) subtropical. For

OCEANOGRAPHY-VoI.9, NO. 1"1996 53 EV 1 (13.2%) 7- ...... 1992; Childers et al., 1993; Dame and Libers, 1993). In brief, the Eastern oyster appears to form a "heterotrophic hot spot" (Bahr and Lanier, 1981) and is a classic example of a keystone species of the coastal-zone ecosystem. The implications for the dy- namics of coastal species are profound. If one ac- cepts that oyster reefs are keystone that affect estuarine dynamics, and if one also accepts that estuaries play essential roles in the life histo-

7 ¸ _ . .. ries of coastal species, then it seems inescapable that oyster reefs also help determine the structure

EV 4 (8.9%) - ..... ~ FV .3 i7.2%) of biotic for the coastal zone as a whole. A corollary is that, whereas any one estu- ary may appear to be highly variable on a short time scale, over the large scale of a regional bio- geographic province, the metapopulations of coastal species may appear to possess some sem- blance of "stability." In this sense, estuaries may be conceived functionally as analogous to gaps, which are important in structuring forest (Shugart, 1984). Unfortunately, our ability to apply regional "gap" models for the coastal zone is extremely limited• Many of the attributes of estuaries impor- Fig. 5: Beringian biotic assemblages. Range data for 86 representative in- tant for coastal biota are not included in NOAA vertebrate and invertebrate species were subjected to principal components (1985), e.g., small-scale physical properties, pro- analysis to reveal the following assemblages: (EV1) southeast Bering Sea; ductivity, etc. This means that the NOAA data are (EV2) Beringian shelf," (EV3) Beringian inner shelf," (EV4) North Pacific; insufficient to predict estuarine species distribu- (EV5) Bering Sea slope; and (EV6) Chukchi-Beaufort seas shelf~Bering Sea tions, except in a very general way. That is, these shelf Percentages represent the variance of the total sample explained by data may be useful for developing a general, each vector. Taken together, these overlapping assemblages cover -150% of large-scale, physical estuarine classification, but the entire Beringian shelf region, calling attention to the difficulties in iden- whether they can be used to correlate biotic and tifying a "hot-spot" for regional conservation. From Ray and Hayden physical estuarine characteristics, as has been at- "1993). tempted by Monaco and Lowery (1993) and Monaco et al. (1992), is doubtful. Nevertheless, the strong dependency of many coastal species on each, many species range beyond the points of estuaries and the apparent functional differences inflection for the province boundaries. A concur- among the estuaries themselves support the con- rent analysis of 18 physical-estuarine variables clusion that estuarine function is a major influence from NOAA (1985) resulted in five attributes that on species distributions over the adjacent shelf• are of consequence to the biota: 1) estuarine di- Thresholds, Breakpoints, Discontinuities, and • . the Eastern oys- mensions, 2) of marine processes, 3) co-dominance of marine and freshwater processes, Flips ter.., is a classic 4) fjordlike attributes, and 5) large surface area. Although the concept of "key" elements of Combinations of these and other attributes result ecosystems is relatively well recognized, the con- example of a key- in a rich array of East Coast estuaries, each of cept of the "," also expressed as stone species of the which supports different assemblages and abun- "stability," still strongly lingers in the public mind dances of species at different . and often seems to drive conservation and man- coastal-zone ecosys- The ecological dynamics within these provinces agement. This concept assumes that ecosystems tem. are strongly influenced by the "keystone" role of have homeostatic properties, incorporating mecha- the Eastern oyster, which builds estuarine reefs nisms that assure dynamic stability, resiliency, that provide the only naturally occurring, hard sub- predictability, and sustained production of re- strate in an otherwise mobile benthic environment sources. Whereas these assumptions have limited of and mud. Oyster reefs affect circulation validity, we now know that environments also un- patterns, tidal flow dynamics, the movements of dergo nonlinear, seemingly chaotic, behavior. , nutrient exchange, , and the Terms such as "threshold," "discontinuity," settlement, shelter, and feeding of estuarine species "breakpoint," and "flip" are used to describe (, 1961; Galtsoff, 1964; Bahr and Lanier, points at which some function or aspect of a sys- 1981; Denny, 1988; Newell, 1988; Dame et al., tem may suddenly be lost. The exact reasons are 1992; Newell and Breitburg, 1992; Wright et al., most often unclear.

54 OCEANOGRAPHY'VoI.9, NO. 1°1996 The logic that biodiversity and stability are re- These examples span a spectrum of spatial scales lated began to be seriously challenged about two from global to local and temporal scales from decades ago, when it became clear that the relation- long-term to almost immediate. They are but a was complex and many-faceted. Orians (1975) tiny portion of the coastal-marine perturbations defined stability variously as constancy, persistence, that are presently being witnessed, worldwide. In- inertia, elasticity, amplitude, cyclical stability, and deed, if all such perturbations are taken into ac- trajectory stability. As Orians noted, attempts to count, coastal systems, where most of the world's "... find general relationships between stability human , are probably as perturbed and diversity are likely to be fruitless" and "... it as any on Earth--and their conservation and man- will be difficult to establish causal relationships be- agement most difficult. tween stability and diversity because we must mea- sure one or more concepts of stability in ecological "Hot Spots"--Conservation on the Griddle systems differing only in some measure of diversity." A central question with regard to biodiversity At about the same time, May (1977) concluded that concerns its conservation and management, and "natural multi-species assemblages of and ani- one of the primary mechanisms for this is pro- mals are likely to possess several different equilib- tected areas. Ray and McCormick-Ray (1994) • . . if all such per- rium points." That is, subsequent to a small perturba- noted "'Protected areas may, hypothetically, be tion, the system may assume a different state, then said to play a role in the conservation of biological turbations are taken return to its initial state. However, large disturbances diversity of coastal-marine systems. The questions into account, coastal may carry the same system "into some new region of are: Do they? Can they, in practice'? And, at what the dynamical .... " which implies more- scale and how completely?" systems, where most or-less permanent, nonreversible change, For more Hundreds of MACPAs exist worldwide, the of the world's human complex situations, with more and more species, May preponderance of which are coastal, only a few noted that models become so complex that "... the being truly marine. Agardy (1994) emphasized population lives, are dynamical landscape can begin to look like the sur- their potential for multiple use, harvest refugia, face of the ." [See Note Added Pro~ ] testing grounds for conservation , ecologi- probably as per- The conclusions are, first, that stability in the cal studies, and (while turbed as any on sense of fixed, unvarying, constant, enduring, and also stressing differences among terrestrial and permanent is not the way ecosystems work. Sec- marine systems, about which more below). These Earth--and their con- are cast as "'advances in " and ond, "discontinuities," or alterations described by servation and man- any other name, are devilishly difficult to define well they could--or should--be. However, it and even worse to predict. Third, although the seems clear that most such "advances" are promis- agement most structures and functions of ecosystems and their sory notes, yet to be demonstrated. For among difficult. biota are coadapted, their ecological time constants MACPAs, no true network exists, research and may not necessarily match. If important ecosystem monitoring are not well developed, and long-term, components go awry, the result may be species de- sustainable, multiple use within harvest refugia has pletion or on the one hand, or simply not been demonstrated• The fact is that most another structural-functional ecosystem state. The MACPAs have been established ad hoc and for a final and major point is that various ecosystem great variety of reasons• Dynamic biogeography states and disfunctions are describable in terms of has been little considered, if at all. On the con- dynamic biogeographic change. This is evident in trary, selection of MACPA sites remains domi- the following examples. nated by seeking "representative" environments, static descriptors, and the selection of "'hot spots." • Alterations produced by the invasion of the Chi- Recent reviews (Kelleher and Kenchington, nese clam Potamocorbula amurensis in Califor- 1992; Norse, 1993; World Bank, 1995) present nia (Butman and Carlton, 1995); criteria for MACPA selection that are remarkably • The deterioration of reefs in the Florida similar to those of the first International Confer- Keys and Caribbean Basin (Jackson, 1994); ence on Marine Parks and Reserves (IUCN, 1976), • The effects of global transportation of non- these include "rare biogeographic qualities," "'rep- indigenous marine organisms, with severe dis- resentative types," "unique or unusual features," ruptions of structure (Carlton and "essential ecological processes," "'integrity," "en- Geller, 1993): dangered species," "'nursery or juvenile areas," • The consequences of widespread , "feeding, breeding or rest areas," "rare or unique especially in coastal seas, with effects on habitat," "'," "," and the species diversity, , and like. Application of such "hot spot" criteria is (Gray, 1982); and fraught with problems. First, they are prescriptions • Large-scale shifts in climate that trigger disease for a static world, one in which environmental outbreaks and that cause the near elimination of change is presumed not to occur, or at least is not top , with subsequent marked conse- made explicit. Second, according to the aforemen- quences for local community structure (Dungan tioned criteria, the whole world is included! et al., 1982). Clearly, if one were to include all taxa, all ecolog-

OCEANOGRAPHY'VoI.9, NO. 1"1996 55 tinctness of the coastal zone (Ketchum, 1972; Hayden et al., 1984; Holligan and de Boois, 1993), and for this reason alone, the key criterion of "representativeness" is likely to be miscon- strued. Pressey et al. (1993) recognize the need for reserves to "contain as many examples of as many elements of biodiversity as possible," and for "combining sites into representative net- works." They suggest three objective, quantitative principles for achieving this goal: complementar- ity, flexibility, and irreplaceability. Their method is highly dependent on knowing the species that are present--difficult enough for and , but almost an impossibility for the many smaller, more mobile organisms of the land or sea. These authors suggest that another starting point may be needed: "The definition of 'representative' needs to be extended to cover, not only examples of land types or of species, but the temporal and spatial dynamics being addressed by land- scape and metapopulation dynamics." In sum, the selection of areas to be protected seems often driven by criteria that fragment the web of life. The hot spot as a magic bullet for conservation of biodiversity conceives of the exis- tence of "cold areas" of little worth. This seems odd considering the fact that conservation empha- sizes the unity of life, that "" cannot be attained other than by ecosystem principles, and that no place is valueless. It is especially problematic to assume that known species rich- ness confers higher priority on one area over an- other. Coral reefs are widely regarded as the wet- biodiversity equivalents of tropical forests. But because they may hold more species, do they, therefore, deserve higher priority than, for the sake of argument, the Southern (Fig. 6)? Should the tropics be judged more valuable for the species diversity of their coral reefs than the tem- perate seas for their oyster reefs and pro- duction, or the polar regions for their abundances Fig. 6: Top, a tropical-Bahamian reef assemblage. Is this species-rich sys- of whales, seals, walruses, , and auklets? tem more valuable than the assemblage shown below? Bottom, a assemblage of 3 species from McMurdo Sound, Antarctica: an octo- Future Implications pus (Octopus), a starfish (Odontaster), and a sea urchin (Sterechinus). Many It is my thesis that the major integrating factor endemics are restricted to those waters. Is this system of lesser value than for the ecology, conservation, and management of that above? Photographs by G. Carleton Ray. coastal-marine biological diversity is dynamic bio- , primarily at the level of the land- seascape. This is to say that a species approach is ical processes, and all nursery and other "critical" a poor surrogate for ecological function, complex- areas, the entire planet would be covered more ity, resilience to stress, etc., and that species rich- than once over! For it is a fact that the entire sur- ness is certainly not a reliable measure of conser- • . . the entire sur- face and depths of Planet Earth provides so-called vation priority or "value." Rather, multiscale, face and depths of hot spots for some living thing, as a consequence functional relationships of coastal water- sheds/seasheds and large marine ecosystems pro- Planet Earth provides of four-plus billion years of biological . Our analysis of Beringian assemblages (Fig. 5) il- vide the context for ecosystem conservation and so-called hot spots lustrates this point. management. This requires the recognition of hier- In short, the hot-spot selection process takes lit- archies of scale as a fundamental operational prin- for some living thing tle account of ecosystem theory, current thoughts cipal. In this context, species' natural history may about biogeography, or environmental change. Lit- provide the fundamental links toward greater un- tle recognition is given to the biogeographic dis- derstanding of complex ecological problems

56 OCEANOGRAPHY'Vo1. 9. No. 1"1996 (Bartholomew, 1986). That is, greatly increased at- to conserve processes, even though we can never tention should be given to the specific life-history lose concern for the species themselves {Franklin, characteristics that "'connect" species ranges to 1993}. The following principles, therefore, apply: habitat-scale distributions, as I have tried to show in the case of the oyster. • Coastal-marine biodiversity may best be repre- Efforts are now underway to develop interna- sented at the level of the land- and seascape, tional (Grassle et al., 1991; Lasserre et al., 1994) with lesser attention given to species; and U.S. (NRC, 1995) coastal-marine research pro- • Coastal-marine science and conservation-man- grams to examine the functional role of marine and agement must be scaled to regional attributes coastal biodiversity. NRC {1995) identifies as one and processes, with special attention given to of its five major objectives: "'to understand the pat- land-sea interactions in the coastal zone; terns, processes, and consequences of changing • Models that attempt to predict population fluctu- marine biological diversity by focusing on critical ations and the demographics of coastal-marine environmental issues and their threshold effects, species should explicitly include the life-history and to address these effects at spatial scales from dynamics of key species in their design; local to regional and at appropriate temporal • Criteria for ecological "representativeness" and scales." In this connection, the existence of the national or international "significance" will need coastal zone, which is dominated by land-sea inter- to be made explicit in terms of the time and actions, forces us to challenge much of the mythol- space scales of species assemblages and ecolog- ogy of land-sea differences. In fact, the assumption ical interactions; and is often made that differences between land and sea • Networking among scientists and conservation are so great that, almost reflexively, their common is essential. Coastal-marine sci- properties may be ignored• The NRC (1995) has ence and conserva- listed "distinctive features of marine ecosystems": I conclude with an emphasis on networking. This has two indivisible components: 1) detailed tion-management and intimate communication on issues of both sci- • Marine primary producers are mostly small and must be scaled to mobile, whereas terrestrial ones tend to be large entific understanding and stewardship and 2) the and sessile: establishment of comparative methods so that in- regional attributes • Large marine predators have a greater range of formation from individual sites may be ecologi- and processes, with life-history characteristics, and higher reproduc- cally and biogeographically related• As for the sci- tive outputs; ence, comparative approaches are possible through special attention • Biomass of marine systems is thousands to hun- the development of a dynamic biogeography for given to land-sea dreds of times more dilute than for terrestrial the world's and coastal zones. By such systems: means, regional problems, such as the die-off of interactions in the * Marine systems are "'open" in the sense of being the Caribbean sea urchin, Diadema (Lessios et aI., linked by larval dispersal; and 1984) may be evaluated, and the possible global coastal zone • The higher order diversity of is sub- effects of the sea's warming might be linked to stantially richer. (Glynn, 1991). With respect to sci- entific networking, large-scale, scientific require- Surely, land and sea are different in many ways, but ments include (Parsons and Seki, 1995): 1) the I have emphasized words that indicate that these flows of energy, 2} the recycling of biologically "differences" are mostly of degree and important elements, 3) the life cycles of the biota, scale. As for marine systems being "open," NRC and 4) the information within ecosystems in terms { 1995) notes that the sea is not just a "vast homoge- of biodiversity. In addition to the science, how- neous body of water," but has sharp divisions, and ever, networking must serve to communicate that the benthos behaves ecologically similarly to among at least three additional sectors, all with the land. Steele et al. (1989) admitted to land-sea differing viewpoints and time constants: manage- differences in many respects, but concluded that ment, conservation, and public policy. Admittedly, "'So far the terrestrial and marine sectors have been science itself can be a significant part of the com- considered separately... But the critical question munication problem, due to its own peculiar cul- is whether the science itself requires this division.. ture. On the other hand, much of conservation • the perceived need to view our world as a single "seems too divorced from the scientific base from system requires ecological theory and practice to which must come the knowledge it seeks" (Angel, achieve a strong common basis .... No single 1991}. If the science alone were not difficult "axis" can bring together the contrasts among ma- enough, the social dynamics of biodiversity may rine, terrestrial, and freshwater ecosystems." be even more so, making networking possibly our In conclusion, it appears self-evident that biodi- greatest future challenge. versity can best be made relevant to conservation and management in ecosystem terms. This is Acknowledgements mainly true because most species are currently un- This paper was supported by the Global Biodi- known, and an ecosystem approach is the best way versity Fund of the University of Virginia, through

O{'I:AN{}{;I~APHY-VoI. 9. No. 1.1996 57 the generosity of Mrs. Sara S. Brown of Louis- Glynn, P.W., 1991: bleaching in the 1980s and pos- ville, Kentucky; the Munson and Henry Founda- sible connections with global warming. . 6. 175-179. tions of Chicago, Illinois; and Edward M. Miller Grassle, J.F., P. Lasserre, A.D. McIntyre and G.C. Ray, 1991: of Charlottesville, Virginia. For the review of es- Marine Biodiversity and Ecosystem Function. Biol. htt. tuarine dynamics, B.P. Hayden and M.G. Mc- Spec. Publ.. 23. 19 pp. Cormick-Ray were supported, in part, by the Divi- Gray, J.S., 1982: Eutrophication in the sea. In: Marine Eu- sion of Environmental Biology, National Science trophication and . G. Colombo, 1. Ferrari, V.U. Ceccherelli and R. Rossi, eds. Olsen and Grant BSR 8702333-02. Dr. C.R. Olsen. Fredensborg, Denmark, 3-15. Robins, formerly Maytag Professor of Ichthyol- Hayden, B.P., G.C. Ray and R. 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