Scientiﬁc requirements for ecosystem-based management in the … CB... · 2020-01-06 · Although frameworks exist for integration of management objectives in both regions,

Ecological Engineering 26 (2006) 6–26

Scientific requirements for ecosystem-based managementin the restoration of Chesapeake Bay and

Coastal Louisiana

Donald F. Boesch∗

University of Maryland Center for Environmental Science, Cambridge, Maryland 21613, USA

Received 10 September 2004; received in revised form 23 March 2005; accepted 26 September 2005

Abstract

Ecosystem-based management requires integration of multiple system components and uses, identifying and striving for sus-tainable outcomes, precaution in avoiding deleterious actions, and adaptation based on experience to achieve effective solutions.Efforts underway or in planning to restore and manage two major coastal ecosystems, the Chesapeake Bay (Chesapeake BayProgram) and coastal Louisiana (Louisiana Coastal Area Plan and Gulf Hypoxia Action Plan), are examined with respect tothese four principles. These multifaceted restoration programs represent among the foremost challenges for science and coastalmanagement in the United States and, thereby, have important implications for addressing the coastal environmental crisesbeing experienced throughout the world. Although frameworks exist for integration of management objectives in both regions,the technical ability for the quantitatively integrated assessment of multiple stressors and strategies is still in an early stage of

resilienced becomeAdaptiveplementedbe advancedcross-

ention tosilience; (4)deling,

hesapeake

development. Science is also being challenged to identify sustainable futures, but emerging concepts of ecosystemoffer some promising approaches. Precautionary management is best conceived with regard to fisheries, but shoula more explicit consideration for managing risks and avoiding unanticipated consequences of restoration activities.management is embraced as a central process in coastal Louisiana ecosystem restoration, but has not formally been imin the more mature Chesapeake Bay restoration. Based on these experiences, ecosystem-based management couldby: (1) orienting more scientific activity to providing the solutions needed for ecosystem restoration; (2) building bridgesing scientific and management barriers to more effectively integrate science and management; (3) directing more attunderstanding and predicting achievable restoration outcomes that consider possible state changes and ecosystem reimproving the capacity of science to characterize and effectively communicate uncertainty; and (5) fully integrating moobservations, and research to facilitate more adaptive management.© 2005 Elsevier B.V. All rights reserved.

Keywords: Ecosystem-based management; Integration; Sustainability; Resilience; Precautionary approach; Adaptive management; Cbay; Coastal louisiana

∗ Tel.: +1 410 228 9250.E-mail address: [email protected].

0925-8574/$ – see front matter © 2005 Elsevier B.V. All rights reserved.doi:10.1016/j.ecoleng.2005.09.004

D.F. Boesch / Ecological Engineering 26 (2006) 6–26 7

1. Introduction

Progressive concepts of “ecosystem-based man-agement” (EBM) emphasize four common principles,namely that effective management must: (1) beintegrated among components of the ecosystemand resource uses and users; (2) lead to sustainableoutcomes; (3) take precaution in avoiding deleteriousactions; and (4) be adaptive in seeking more effectiveapproaches based on experience. For example, thetwo recent commissions charged with recommendingnew ocean policies for the United States stressed theseelements.

ThePew Oceans Commission (2003)placed partic-ular emphasis on the need for EBM of fishery resourcesand included “practice sustainability” and “apply pre-caution” among the guiding principles for a new oceanethic. It further indicated that: “scientific programsshould utilize adaptive management to assess results,learn from experience, and adjust incentives, regula-tion, and management accordingly”.

The report of the presidentially appointedU.S.Commission on Ocean Policy (2004)also stressedEBM as the cornerstone of the path forward forthe nation’s ocean policy, meaning that managementshould reflect the relationships among all ecosystemcomponents, including humans and nonhuman speciesand the environments in which they live. The U.S. Com-mission stressed that this management should balance[integrate] competing uses while preserving and pro-t stalr then isingt eds.T om-m ingw dap-t lables

thed able,p sys-t ved.T dif-fi thea pha-s tem-b t sci-

entific information and the effective application ofknowledge. While environmental scientists are gener-ally familiar with the four principles, relatively few ofus are actively engaged in directly filling their require-ments. The objective of this paper is to point to waysscientific contributions can be improved in response tothe emerging consensus on ecosystem-based manage-ment, not only in the U.S. but also around the world.

To advance beyond the abstract and general plati-tudes, I will examine a particularly pressing manage-ment challenge, namely the restoration of degradedcoastal ecosystems, using as case studies the ecosys-tems of the Chesapeake Bay and coastal Louisiana.These examples are particularly appropriate becauseof their national and even international prominence,their extremely large size and complexity, and the exis-tence of substantial organized efforts to restore them.Although physiographically different, the two ecosys-tems share many similar issues, including eutrophi-cation and other consequences of landscape changeswithin their catchments, habitat losses, fishery declines,toxic contamination, invasive species, and navigationaccess. The paper builds on an earlier contribution(Boesch, 2001) with expanded and updated evalua-tion. My objective is to identify paths forward, throughwhich science may more effectively address the needsof management for integration, sustainability, precau-tion and adaptation.

2

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pol-i ent( oft thec AsK nr tal,i ongu Mv ses,a icy’s( butt manu ting

ecting the overall integrity of the ocean and coaesources and achieve sustainability by meetingeeds of the present generation without comprom

he ability of future generations to meet those neo put these principles into practice, the U.S. Cission reported, requires aligning decision-makithin ecosystem boundaries, precautionary and a

ive management, and the use of the best avaicience and information.

Although there may be disagreements amongefinitions of and approaches to integrated, sustainrecautionary, and adaptive management of eco

ems, few would object to the basic concepts involhe problem is that these characteristics are morecult to achieve in practice than to articulate inbstract. Yet it is clear, as the U.S. Commission emized, that all four of these dimensions of ecosysased management require robust and relevan

. Four key management principles

.1. Integration

Integration as used by the management andcy community, as in Integrated Coastal ManagemICM), generally implies collective considerationhe uses of products and services provided byoastal environment to determine an “optimal mix”.necht and Archer (1993)pointed out the integratio

equired is itself multidimensional: intergovernmenntermedium (air, land and water), intersectoral (amsers), and interdisciplinary. Integration, from this ICiew, is centered on balancing competing human us reflected in the U.S. Commission on Ocean Pol2004) principle of “multiple use management”,he Commission adds that managing multiple huses should be done “while preserving and protec

8 D.F. Boesch / Ecological Engineering 26 (2006) 6–26

the overall integrity of the ocean and coastal environ-ments”.

The U.S. Commission uses the term “ecosystem-based management” rather than “ecosystem manage-ment” (Christensen et al., 1996) to accommodatehuman uses while preserving ecosystem integrity, orthe similar concept of ecosystem health as used bythePew Oceans Commission (2003). A recent consen-sus statement by marine scientists (COMPASS, 2005)takes a somewhat reversed perspective, defining thegoal of EBM as maintaining an ecosystem in a healthy,productive, and resilient condition so that it can providethe services humans want and need. From these scien-tists’ point of view, EBM should explicitly account forthe interconnectedness within the ecosystem, recogniz-

ing the importance of interactions between many targetspecies or key services and other non-target species;acknowledge interconnectedness among ecosystems,such as between air, land and sea; and integrate ecolog-ical, social, economic, and institutional perspectives,recognizing their strong interdependences.

Human uses obviously have consequences toecosystems in addition to the direct conflicts amongthese uses. Furthermore, changes in ecosystems result-ing from some human uses affect other human uses andbehaviors. And application of EBM can have profoundsocial and governance implications (Hennessey andSoden, 1999). For these reasons, analysts are increas-ingly envisioning humans and the natural world as inex-tricably linked in “socioecological systems” (Carpenter

F1Gs

ig. 1. The coastal ecosystems of Louisiana and the Chesapeake Ba765 map by English cartographer Thomas Kitchens. The map showulf of Mexico, which interdigitate to the east with the upper reaches o

ounds on the Atlantic coast.

y are heavily influenced by what happens on the land, as illustrated by thiss the vast extent of the rivers of the Mississippi River basin draining to thef the great tidal rivers of the Chesapeake Bay and Ablemarle and Pamlico


et al., 2001) in which changes in ecosystems and humaninstitutions are linked in their dynamic, and even cyclic,behavior (Holling et al., 2002).

Managing coastal ecosystem restoration almostalways involves addressing multiple stressors that havechanged the ecosystem to an undesirable state. Thesetypically include habitat changes, excessive inputs oftoxic or biostimulatory materials, alterations in thedelivery of fresh water and sediments from land tothe coastal ecosystem, and the consequences of liv-ing or non-living resource extraction. The effects ofnon-indigenous species, human-induced hydrologicalchanges and land subsidence, and climate change mayalso be important challenges to ecosystem restorationin some regions. However, management as well as sci-ence traditionally addresses one stressor at time. Evenin ecosystems where one is paramount, the others arecan seldom be ignored.

Furthermore, many coastal ecosystems, and particu-larly the two addressed in this paper (Fig. 1), are heavilyinfluenced by human activities well inland, far removedfrom their shores. Restoration of coastal ecosystemsat the terminus of such large drainage basins requiresscientific assessment and management scope that tran-scends many boundaries: ecological, social, and polit-ical (Jickells et al., 2001). How, then, can we makeprogress for science and management in integratingstressors and the human behaviors that cause them oversuch large regions?

2

ithi heB ter-g tain-a houtc eett enti ive oft nda2 andD nd-i ent,c taina ns( nvi-r ps in

society and nations, and does not foreclose options offuture generations (Cicin-Sain, 1993). ThePew OceansCommission (2003)simply stated that “the essence ofsustainable development is using our planet’s resourcesas if we plan to stay”.

Achieving sustainability is interdependent with theother management characteristics considered here.Costanza et al. (1998)espoused six principles forsustainable governance of the oceans: responsibility,scale-matching, precaution, adaptive management, fullcost allocation, and participation. Matching the scalesof governance to those of ecological problems andfull-cost allocation necessarily depends on effectivescientific integration as discussed above. The principlesof precaution and adaptive management are discussedlater.

Given the rapidly expanding human population,increasing per capita consumption of many resources,and the already substantial and growing human domi-nation of Earth’s ecosystems (Vitousek et al., 1997), itis difficult to be sanguine about the prospects of achiev-ing sustainable development. However, theNationalResearch Council (1999)concluded, based on anal-ysis of persistent trends and plausible futures, that asuccessful transition toward sustainability is possibleover the next two generations, even without miraculoustechnologies or drastic transformations of human soci-eties. This transition will require “significant advancesin basic knowledge, in social capacity and technolog-ical capabilities to use it, and the political will to turnt

q wl-e ems,l vul-n d-a iousd heya temsf ert tteri ess-m menta

opedw wl-e gicalc por-

.2. Sustainability

“Sustainable” is a word frequently used wmplied, but not carefully defined, meaning. Trundtland Commission stressed the important inenerational aspect of the concept by defining susble development as “satisfying present needs witompromising the ability of future generations to mheir own needs” and this intergenerational requirems, as related earlier, encompassed in the perspecthe U.S. Commission on Ocean Policy. In its Age1, the United Nations Conference on Environmentevelopment (UNCED) promoted even more dema

ng social requirements for sustainable developmalling for economic development needed to susnd improve the quality of life of human populatioi.e. sustainable economically and socially) that is eonmentally sustainable and equitable among grou

his knowledge and know-how into action”.Toward that end,Kates et al. (2001)offered core

uestions for sustainability science, including knodge of lags and inertia in natural and social syst

ong-term trends reshaping these systems, theirerability or resilience, meaningful limits or bounries beyond which there is increased risk of seregradation, and effective incentive structures. Tlso stressed the importance of operational sys

or monitoring and reporting on conditions in ordo navigate a transition toward sustainability and bentegration of research planning, monitoring, ass

ent, and decision support for adaptive managend societal learning.

Restoration of coastal ecosystems in the develorld, where populations are relatively stable, knodge is advanced, and social capacity and technoloapabilities are substantial, offers a compelling op


tunity for the journey to sustainability. In the case ofthe coastal ecosystems we are trying to restore, it is cer-tainly the case that their deterioration has been due tounsustainable human activities. The intergenerationalconsequences of these activities—dredging of oysterreefs in Chesapeake Bay and Atchafalaya Bay or com-pletely constraining the lower Mississippi River, forexample—were either not realized or were disregardedbecause of more immediate socioeconomic require-ments. How then can we, at least on regional scales,reverse this previous track record, avoid such unsus-tainable practices in the future within an already greatlyaltered landscape, and repair the damages in a lastingway?

After decades of overexploitation of marine fish-eries, we now try to restrict fishing pressure so as notto exceed optimum sustainable yields. By estimatingTotal Maximum Daily Loads, we are working to reduceinputs of pollutants so that water quality standardsneeded to support designated uses are not exceeded.For some estuaries, allocations of freshwater inflowsare being made in order to sustain reproductive successof fishes. Such approaches do not specifically integrateamong ecosystem functions and services, however,and a more comprehensive dimension of sustainabil-ity is emerging with growing attention to ecosystemresilience as a management objective.

Resilience is commonly defined as the capacity ofa system to undergo disturbance and maintain its func-tions and controls. It can be measured by the magnitude

of disturbance the system can tolerate and still persist(Gunderson, 2000; Gunderson et al., 2002). In addi-tion to serving as a metaphor related to sustainability,resilience is both a property of dynamic models and aquantity that can be measured based on three prop-erties: (a) the magnitude of disturbance that can beabsorbed before the system is restructured with differ-ent controlling variables and processes; (b) the degreeto which the system is self-organizing; and (c) thedegree to which the system can build capacity to learnand adapt (Carpenter et al., 2001). In this sense “sys-tem” refers to the socio-ecological system and implic-itly includes society and its institutions.

A paradigm is emerging that restoration strategiesshould have as an important, if not central, objective therecovery and maintenance of a desired level of ecosys-tem resilience in its performance and delivery of goodsand services. However, asGunderson et al. (2002)pointout, the stability domains of ecosystems are dynamicand variable. As ecosystems degrade and lose previousresilience characteristics, the new state may becomequite resilient (e.g. a eutotrophic lake) and can only berestored by altering the forces that shape the stabilitydomains (Fig. 2).

2.3. Precaution

The precautionary principle states that if the con-sequences of an action are potentially adverse, theaction should not be allowed to proceed, even if cause

F in of ec ble domain.R ase ec

ig. 2. Ecosystem degradation can change the stability domaestoration involves reshaping the stability domains that incre

osystems with multiple stable states to one with only one staosystem resilience (modified fromGunderson et al., 2002).


and effect relationships have not been fully establishedscientifically. This principle had its origins in multina-tional conferences in the 1980s that addressed the dis-charge of chemicals into the North Sea. It has since beenapplied or debated relative to a broad array of issueswhere there is risk and uncertainty, including persistentpollutants, fisheries management, species extinction,genetically modified organisms, disease transmission,food safety, and climate change (Tickner, 2002). Aprecautionary approach has been embraced in vari-ety of policy instruments from the UNCED Agenda21 to the Magnuson-Stevens Sustainable FisheriesAct.

The precautionary principle has been criticized asimpractical, requiring too high a requirement for cer-tainty and as focusing excessively on new technologiesor activities and less on those that have caused theproblems we already have. To the degree to which aprecautionary approach is interpreted to mean “do nottake chances”, it could be an impediment to under-taking restoration actions for which the outcomes areuncertain and to pursuing experimental, adaptive man-agement approaches (Boesch, 1999).

The U.S. Commission on Ocean Policy (2004)calls for a more balanced precautionary approach “thatweighs the level of scientific uncertainty and potentialrisk of damage as part of every management action”.Such an approach would apply judicious and responsi-ble management practices, based on the best availablescience and on proactive, rather than reactive, policies.A iouso er-t inga hal-l andc abil-i ncer-t pleo ni-t idedb

2

an-a ty ino co-n ment

actions. New understanding, experience, and changingsocietal expectations inevitably mean that priorities,goals and approaches must change. Europeans refer tothe iterative cycle of environmental policy adjustmentthe DPSIR framework, meaning the interconnection ofdriving forces, pressures, states, impacts, and responses(Turner et al., 2001).

In the U.S. the concept of adaptive management hasdeveloped as a more structured approach to allow man-agers to take action in the face of uncertainties, enhancescientific knowledge to reduce the uncertainties, andrespond to unanticipated events (NRC, 2004b). Adap-tive management involves implicitly learning by doingand treating management programs as experiments,with a great emphasis on accounting for outcomes,but it is not simply a “trial and error” process (Lee,1999). Adaptive management requires: (a) manage-ment objectives that are regularly revisited and accord-ingly revised; (b) models of the system being man-aged; (c) a range of management choices; (d) mon-itoring and evaluation of outcomes; (e) mechanismsfor incorporating learning into future decisions; and (f)a collaborative structure for stakeholder participationand learning (NRC, 2004b). Applications can rangefrom “passive” adaptive management, which focuseson monitoring and evaluating outcomes from a partic-ular policy option, to “active” adaptive management,which includes experiments to test competing modelsof system behavior or alternative solutions.

Adaptive management is particularly being plannedo vingh quin-S ades.I ys-t andu en-t d byt andr evera verym ofc abouti oni-t sm nt ofa ter-p ithd

s the Commission stated: “where threats of serr irreversible damage exist, lack of full scientific c

ainty shall not be used as a justification for postponction to prevent environmental degradation”. A c

enge for science, then, is to collect informationreate knowledge that conveys the range and probties of outcomes and expresses the associated uainties with those predictions. An interesting examf combining expert judgment, including the mag

ude of uncertainty, and stakeholder values is provy Failing et al. (2004).

.4. Adaptation

Adaptation is a dimension of ecosystem-based mgement necessitated by the inherent uncertainur predictions about the natural world, socioeomic developments, and the outcomes of manage

r applied to coastal ecosystem restoration involydrological readjustments, such as in the San Joaacramento delta, coastal Louisiana, and Evergl

t may be particularly suited to large, complex ecosem restoration efforts that entail considerable riskncertainty, multiple objectives and phased implem

ation. Adaptive management has been embracehe Corps of Engineers for ecosystem restorationecommended by both ocean commissions. Howppealing, though adaptive management is stilluch a work in progress often beset with lack

lear understanding of its processes, reservationsts risks, and failures to meet requirements for moring and assessment (Walters, 1997). This presentany challenges to science in terms of developmeppropriate models, effective design and timely inretation of monitoring, and active engagement wecision-makers and stakeholders.


3. Background on the ecosystems

3.1. Chesapeake Bay

The Chesapeake Bay is the largest estuary in theUnited States and one of the largest in the world. Itsmain stem is 332 km long, with tidal waters extendingover 11,400 km2 and 12,870 km of shoreline. TheChesapeake drainage basin covers 166,000 km2

in six states. The bay is relatively shallow (meandepth 6.5 m); therefore the area of its catchment isunusually large in comparison to the estuarine volume.This, coupled with its modest tidal exchange, makesthe bay very susceptible to inputs of fresh water,sediments and dissolved materials from the land(Horton, 2003).

Approximately 16 million people live in the Chesa-peake basin, with the largest concentrations at thetidal headwaters of estuarine tributaries around theWashington, DC, Baltimore, Richmond, and Norfolkmetropolitan areas. The bay includes important com-mercial and military ports and is a valuable recreationalresource. Although a number of the historically impor-tant fisheries (particularly oysters) have declined, thebay still supports commercial fisheries worth approxi-mately $1 billion per year. The estuary is also heavilyused for domestic and industrial waste disposal, withabout 5000 point-source discharges into the estuary ordrainage basin.

The Chesapeake ecosystem has undergone sub-s n byE aseds vi-o riane orep thatt n tow ro-d 9thc et-a t thea sivero ont ingm ides,p fer-t

Although there were cumulative, human-inducedchanges in the Chesapeake Bay through the early 20thcentury, during the later part of that century the estu-ary experienced an even more dramatic state changefrom a relatively clear-water ecosystem, characterizedby abundant plant growth in the shallows, to a turbidecosystem dominated by abundant microscopic plantsin the water column and stressful low-oxygen condi-tions during the summer (Hagy et al., 2004; Kemp etal., in press). This state shift was largely due to thedramatic increase in nutrient inputs in the form ofwastes from the growing population, runoff of agri-cultural fertilizers and animal wastes, and atmosphericdeposition of nitrogen oxides resulting from fossil fuelcombustion. By the mid-1980s the Chesapeake Baywas receiving about seven times more nitrogen and 16times more phosphorus than when English colonistsarrived (Boynton et al., 1995). In addition, the drasticdepletion of the once prodigious oyster populations andloss of wetlands and riparian forests diminished impor-tant sinks for nutrients and sediments within both thewatershed and the estuary.

In the 1970s the scientific community began tounderstand and document the pervasive changes in theecosystem that had taken place and to identify theircauses. This led to growing awareness by the publicand political leaders, which in turn resulted in the evolu-tion of regional management structures and restorationobjectives (Hennessey, 1994; Boesch et al., 2001a,b).Starting with a simple agreement in 1983 “to assessa lanst ingr ems,”t onalc theC ies ofd utri-e ingr ent.

t per-v arka s the1 ofn byt leart re, ac iron-m ties

tantial human-induced changes since colonizatiouropeans almost 400 years ago, including increedimentation resulting from clearing of its preusly forested watershed. During the period of agraxpansion extending into the early 19th century, mlant nutrients—forms of nitrogen and phosphorus

he native forests efficiently retained—also begaash down into the Bay, subtly altering its natural puction and food web. Industrialization later in the 1entury increased pollution, particularly by trace mls, and provided the mechanical means to exploibundant oysters, effectively strip-mining the exteneefs that gave the bay its Algonquin name,Chesepi-ok or “great shellfish bay”. The mid-1900s broughthe petrochemical period of the Bay’s history, bringanufactured organic chemicals, such as pesticetroleum by-products, and industrially produced

ilizers.

nd oversee the implementation of coordinated po improve and protect the water quality and livesources of the Chesapeake Bay estuarine systhe three primary states in the region, the natiapital district and the federal government formedhesapeake Bay Program and have issued a serirectives and agreements related to reductions of nnt and toxicant loadings, habitat restoration, livesource management, and landscape managem

Because eutrophication was seen as the mosasive and consequential human impact, a landmgreement of the Chesapeake Bay Program wa987 commitment to reduce controllable inputsitrogen and phosphorus entering the bay by 40%

he year 2000. As that year approached it was chat this goal would not be reached and, furthermoomplex array of interrelated issues related to envental quality, living resources, and human activi


Table 1Goals of the proposed Chesapeake 2000 Agreement (Chesapeake Bay Program, 1999b)

1. Restore, enhance and protect the finfish, shellfish, and otherliving resources, their habitats and ecological relationships to sustain all fisheriesand provide for a balanced ecosystem.Oysters: tenfold increaseExotic species: identify and reduce introductionFish passage: restore passage in blocked riversMulti-species management: develop and revise management plansCrabs: restore health of spawning population

2. Preserve, protect and restore thosehabitats and natural areas vital to the survival and diversity of the living resources of the Bay and its rivers.Submerged aquatic vegetation: recommit and raise previous restoration goalWetlands: achieve net gain through regulatory protection and restorationForests: protect and restore riparian forestsStream corridors: encourage local governments to improve stream health

3. Achieve and maintain thewater quality necessary to support the aquatic living resources of the Bay and its tributaries and to protect humanhealth.Nutrients: achieve and maintain 40% goal and reduce further to protect living resourcesSediments: reduce loading to protect living resourcesChemical contaminants: no toxic or bioaccumulative impacts on living resourcesPriority urban waters: restore urban harborsAir pollution: strengthen air emission pollution prevention programsBoat discharges: establish “no discharge zones”

4. Develop, promote and achievesound land use practices which protect and restore watershed resources and water quality, maintain reducedpollutant loadings for the Bay and its tributaries, and restore and preserve aquatic living resources.Land conservation: protect and preserve forests and agricultural landsPublic access: expand public access pointsDevelopment, redevelopment and revitalization: reduce rate of land developmentTransportation: coordinate with land use planning to reduce dependence on automobiles

5. Promoteindividual stewardship and assist individuals, community based organizations, local governments and schools to undertake initiativesto achieve the goals and commitments of this agreement.Public outreach and education: provide information about Bay to schools and publicCommunity engagement: enhance small watershed and community-based actionsGovernment by example: develop and use government properties consistent with goals

Specific objectives and actions under each goal are briefly summarized.

needed to be addressed in a more comprehensive man-ner. The Chesapeake 2000 Agreement was reached,which includes over one hundred goals and commit-ments that together comprise one of the most ambitiousecosystem management programs for a large coastalarea (Table 1).

Progress in restoring the Chesapeake Bay ecosys-tem has been mixed. Although eutrophication is nolonger growing, there is a very public debate con-cerning the amount of nutrient load reductions thathave been achieved (Whoriskey, 2004) and few clearsigns that the symptoms have been alleviated, exceptlocally. The concentrations of a number of potentiallytoxic substances (some trace metals and chlorinated

hydrocarbons) in sediments and organisms declinedas a result of source controls and waste treatment.Yet, the industrialized harbors in the bay remain heav-ily contaminated and other subregions show elevatedconcentrations of toxicants or evidence of biologicaleffects. Seagrasses have returned in some regions butcover only a small portion of the habitat occupied inthe 1950s. Oyster (Crassostrea virginica) populationshave not recovered because of the degraded reef habitatand ravages of two microbial pathogens. Populationsof several anadromous fishes have increased modestlyas a result of removal of barriers to upstream migration.Perhaps the most dramatic recovery has been for popu-lations of striped bass (Morone saxatilis), which greatly


increased as a result of a multi-year moratorium onharvest and subsequent, more precautionary manage-ment of stocks. On the other hand, the very productiveblue crab (Callinectes sapidus) fishery has shown somedecline and signs of recruitment over-fishing.

3.2. Coastal Louisiana

The coastal ecosystems considered here are atleast as extensive as the Chesapeake Bay, but lesswell-defined. They include the two provinces of theLouisiana Coastal Area (LCA), the Mississippi DeltaicPlain and the Chenier Plain to the west (Boesch etal., 1994), and the adjacent inner continental shelf.The Deltaic Plain consists of the mostly inactive dis-tributaries of the river and extensive tidal wetlands,swamps, and lagoons lying between the distributariesor enclosed by fringing barrier islands. The ChenierPlain developed as a result of the interplay of threecoastal plain rivers and the longshore transport of sedi-ments escaping the Mississippi-Atchafalaya delta sys-tem. The inner continental shelf, which has estuary-likesalinity gradients, stratified water masses, and signifi-cant physical and biological interactions with the LCA,should appropriately be included as an effective part ofthis large coastal ecosystem. This expansive wetland-estuarine-shelf ecosystem supports one of the richestfisheries in the U.S., large populations of migratorybirds, and the substantial majority of the coastal andoffshore oil and gas production in the United States.I stalr oila f them

ver3 usU a. Ite ates,f tot tot allyp ivelyc orn,s theU is-s zedb o,t the

only other significant distributary presently active, theAtchafalaya River, which enters the Gulf of Mexico230 km to the west.

The average annual discharge of water throughthe Mississippi and Atchafalaya rivers to the coastalecosystem is approximately 20,000 m3 s−1, essentiallyan order of magnitude higher than freshwater dis-charge into the Chesapeake Bay. The hydrology of thisvast river system has been greatly altered by locks,dams, reservoirs, earthwork levees, channel straight-ening, and spillways for purposes of flood protection,navigation and water supply. These alterations have sig-nificantly affected the transport of water, sediments anddissolved materials (including nutrients and toxic con-taminants) in ways that have major consequences to thecoastal ecosystem (Turner and Rabalais, 2003).

Disruption of overbank flooding in the delta, wide-spread hydrological modifications caused by myriadcanals, and high rates of subsidence (because of thehuge thickness of alluvial deposits), locally acceler-ated by fluid withdrawals associated with oil and gasproduction have conspired to result in rapid loss oftidal wetlands, particularly during the last half of the20th century. Over 4850 km2 of coastal land, mainlytidal wetlands, have been lost since the 1930s (Barraset al., 2003). Although the annual rate of loss hasslowed somewhat from a peak in the 1970s, it is esti-mated to have been approximately 62 km2 between1990 and 2000, with a projection of 26 km2 y−1 overthe next 50 years. Various efforts have been mountedt orer ndr es oft andR om-p witht arda lW rce,1 stalA ds apC

en-s nti-n( 000t ce

t is one of the most economically important coaegions of the country, with $20 billion annually innd gas and fisheries production alone, and one oost threatened.The catchment of the Mississippi River is vast, o

.2 million km2, including 41% of the conterminonited States and even a small part of Canadncompasses all or part of 30 of the 50 United St

rom the arid west toward the Rocky Mountainshe humid forests of the Appalachian Mountainshe east. The north-central part of the basin, originrairies, forests, and wetlands, has been extensonverted to cropland that produces most of the coybeans, wheat, sorghum, and livestock grown innited States. While 70% of the flow from the Missippi basin is discharged through its well-recogniirdsfoot delta, projecting into the Gulf of Mexic

he remaining 30% (regulated by law) flows down

o stem the loss of coastal wetlands, including mestrictive permitting of dredge and fill activities aestoration projects undertaken under the auspiche federal Coastal Wetlands, Planning, Protectionestoration Act (CWPPRA). Steps toward a more crehensive approach to restoration were taken

he development of the report “Coast 2050: TowSustainable Coastal Louisiana” (Louisiana Coastaetlands Conservation and Restoration Task Fo

998). This has been refined in a Louisiana Coarea ecosystem restoration study that recommenlan of action (the LCA Plan) to Congress (U.S. Armyorps of Engineers, 2004).A more recently recognized problem is the ext

ive seasonal hypoxia in bottom waters on the coental shelf (Rabalais et al., 1996, 2002b). Hypoxic<2 mg L−1) bottom waters have extended over 10,o 20,000 km2 in the summer during most years sin


1990. This phenomenon and other manifestationsof eutrophication have been related to the increasesin nutrient loading by the Mississippi-Atchafalayariver system. In particular, flux of nitrate-N from theMississippi Basin to the Gulf of Mexico has aver-aged nearly 1 million metric tons per year since1980, about three times larger than it was 30 yearsago (Goolsby et al., 1999). The majority of theincreased nitrate emanates from agricultural sourcesin the upper Mississippi and Ohio river basins, over1500 km upstream of the discharge into the Gulf ofMexico.

In response, the U.S. Congress directed the gov-ernment to conduct an assessment of the causes andconsequences of hypoxia in the Gulf of Mexico,including analyses of the potential for reduction ofnutrient sources and associated economic costs. Theresulting integrated assessment (CENR, 2000) presentsmuch more comprehensive evidence concerning nutri-ent sources, trends and effects on oxygen depletion forthe Mississippi-Atchafalaya delta system than existedat the initiation of the Chesapeake Bay Program andits commitments for nutrient reduction, approximately15 years earlier. Subsequently, a task force represent-ing eight federal agencies, nine states, and two tribalgovernments adopted an Action Plan (Table 2) for

reducing the area experiencing hypoxia by two-thirds(Mississippi River/Gulf of Mexico Watershed NutrientTask Force, 2001; Rabalais et al., 2002a); however,measures to implement this agreement have not pro-gressed much at this point.

In addition to wetland loss and eutrophication,ecosystem-based management of the Mississippi deltaregion must also address significant issues in fisherymanagement (including overfishing of some stocks,bycatch mortalities due to shrimp trawling, commer-cial and recreational fishery conflicts, and endangeredspecies concerns); flood protection; navigation; oil andgas exploration, production and transportation; andmigratory waterfowl management.

4. Current state of practice

I now provide brief perspectives on the extent towhich these two ambitious coastal restoration effortshave used science in applying the four principlesof ecosystem-based management: integration, sustain-ability, precaution, and adaptation. Using these exam-ples I will then consider how science can make moreeffective contributions for advancing these four criticaldimensions of informed management.

Table 2Goals and principles of the Action Plan for Reducing, Mitigating and Controlling Hypoxia in the Northern Gulf of Mexico (Mississippi River/Gulfo

C urces, zone tontation llces to

W f the 31 ver Basinand se ife aswater p

Q conom inand reccentive

P1 ctive2 ral regu34 nnual A5

T those o

f Mexico Watershed Nutrient Task Force, 2001)

Goals

oastal Goal By 2015, subject to available resoless that 5,000 km2 through implemejurisdictions and categories of sour

ithin Basin Goal To restore and protect the water othrough implementation of nutrientwell as reduce negative impacts of

uality of Life Goal To improve the communities and eparticular the agriculture, fisheriesmanagement and a cooperative, in

rinciples. Encourage actions that are voluntary, practical and cost effe. Utilize existing programs, including existing State and Fede. Follow adaptive management. Indentify additional funding needs and sources during the a. Provide measurable outcomes as outlined in the three goals

he plan attempts to integrate goals in the Gulf of Mexico with

reduce the 5-year running average areal extent of the hypoxicof specific, practical and cost-effective voluntary actions by a

reduce the annual discharge of nitrogen into the Gulf.

States and Tribal Lands within the Mississippi/Atchafalaya Ridiment reduction actions to protect public health and aquatic lollution in the Gulf of Mexico.

ic conditions across the Mississippi/Atchafalaya River Basin,reational sectors, through improved public and private landbased approach.

latory mechanism

gency budget process; and

f environments and communities within the river basin.


4.1. Integration

The U.S. Commission on Ocean Policy (2004)pointed to the Chesapeake Bay Program as a modelfor regional ecosystem-based management. Indeed, theChesapeake 2000 Agreement goes far beyond the orig-inal focus of the program on water quality with actionsto address habitat, living resources, sound land usewithin the watershed, and even individual stewardship.A hallmark of this program is the setting of ambi-tious quantitative goals and timelines. For example,the 2000 Agreement calls for conserving and restoringforests along 70% of streams in the watershed, restor-ing 10,000 ha of wetlands, preserving 20% of the landarea from development, and increasing the stretches ofrivers open to migratory fish by 2184 km by specificdates, mostly by 2010.

Quantitative understanding and models supportsome of the relationships among these elements of theecosystem. For example, the Chesapeake Bay water-shed model predicts the effects of changes in landuse and management practices on delivery of nutri-ents and sediments to the estuary and from this athree-dimensional eco-hydrodynamic model forecastschanges in water quality, including clarity, chlorophylland light levels, in the estuary. Using these tools onecan forecast with some level of confidence how, forexample, the restoration of forested riparian buffers atspecified places in the watershed should affect nutri-ent loading and environmental conditions in the bay.F thei n ofl ual-iK n-s out-c t besti me-w lityi tofi thisr

t ofc erall oxia( rici cidd data

from throughout the basin and statistical models toestimate fluxes by river segment; and box models ofnutrient and carbon budgets in the Gulf of Mexico.The fact that different modeling approaches are usedto predict the extent of Gulf hypoxia yielded gener-ally similar results boosts confidence in the assessments(Scavia et al., 2004), just as does the convergence ofclimate model predictions of global warming sensi-tivities (Kerr, 2004). Complex, deterministic modelssimilar to those for the Chesapeake Bay and watershedare lacking for the Mississippi basin and continentalshelf, however simpler and more empirical models maybe sufficient to guide the integration of managementof the vast watershed with the management of coastalecosystems. While many improvements can be madein models and their uses, both the Mississippi Riverassessment and the Chesapeake Bay models are lead-ing examples of the power of systemic science for largesystem management. Such integrated assessment andmodeling have helped managers and scientists alike tothink across environmental media, disciplines, and sec-tors (e.g. agriculture, environmental quality and livingresources).

To support the LCA Plan development, a team of sci-entists and engineers undertook extensive hydrologicaland ecological modeling to predict the consequences ofvarious restoration measures and ensembles on salinity,wetland nourishment and land building, habitat suit-ability for various resource species and water quality(U.S. Army Corps of Engineers, 2004, Appendix C).N ateda ctiono ousi cal,a tiono out-c trientr is-tc elfh nlya ippiR ionsc age-m et

m-b ports

urthermore, these linked models can be run innverse mode to determine the regional allocatiooad reductions needed to achieve the water qty requirements of important living resources (U.S.oroncai et al., 2003). However, many other relatiohips among actions, goals and environmentalomes in the Chesapeake 2000 Agreement are, antegrated only through a qualitative conceptual fraork. In particular, the restoration of water qua

s presumed to yield significant positive benefitssheries production, but quantitative evidence forelationship remains sketchy (Kemp et al., in press).

The evolving ecosystem-based managemenoastal Louisiana has involved integration at sev

evels. The integrated assessment of Gulf hypCENR, 2000) involved the analysis of: atmosphenputs of nutrients from data collected to monitor aeposition; land-use characteristics; water quality

,

et benefits for the multiple scenarios were estimnd the relative benefits related to costs in the selef preferred alternatives. The effort involved ambiti

ntegration of understanding of physical, geologind biological processes, with an explicit articulaf ecosystem services expected from the predictedomes. Among those services considered was nuemoval from river water reintroduced into interdributary wetlands and estuaries (Lane et al., 1999) thatould contribute to the alleviation of continental shypoxia. Although such diversions would remove osmall part of the total nitrogen load of the Mississiver, properly located and operated river diversould be a component of a basin-wide nutrient manent strategy (Mitsch et al., 2001) as well as contribut

o coastal wetland restoration.A principal impetus in the call for ecosyste

ased management in the ocean commission re


Fig. 3. Sub-food webs for the striped bass (Morone saxatilis) and blue crab (Callinectes sapidus) in Chesapeake Bay (McBride and Houde,2004).

is the failure of fishery management based solelyon species-by-species considerations. For any givenspecies the interactions among predators (includinghumans) and prey, incidental mortality (bycatch), andhabitat requirements are highly complex (Fig. 3). Formultiple fishery species the task of integration is daunt-ing. This has led to the development of theory andtools for multi-species and, ultimately, ecosystem-based management of fisheries resources (Browmanand Stergiou, 2004). These approaches have empha-sized dynamics of populations and the interactionsamong predators and prey (top-down) rather than thebiogeochemical drivers (bottom up) stressed in themodels previously discussed.

The Chesapeake 2000 Agreement includes a com-mitment to move toward multi-species management offisheries and there has been ongoing development ofscientific approaches (Miller et al., 1996; Latour et al.,2003) that would lead to a Chesapeake Bay fisheriesecosystem plan (McBride and Houde, 2004). Ana-lytic approaches include expansion of single speciesmodels to multispecies virtual population analysis andmodels of trophic interactions such as Ecopath withEcosim (Pauly et al., 2000). Similar network analyticalapproaches that consider a broader array of interactionswithin the ecosystem have provided insights into thecritical functions that have to be addressed in ecosys-tem restoration (Baird and Ulanowicz, 1989; Bairdet al., 2004). Efforts are underway to link the eco-hydrodynamic model developed to predict Chesapeake

Bay water quality with Ecopath models to estimatethe consequences of nutrient load reductions on fish-ery species. As the complexity of linked models grows,however, it becomes more important to avoid putting allthe eggs in one basket. Multiple, less complex modelsmay be more nimble, advance learning more quickly,and result in more practical and routine applications.

Comprehensive ecosystem-based managementmust eventually integrate the consequences of multi-ple stressors that confront these ecosystems, includingeutrophication, toxic contamination, habitat modi-fication, fishing, invasive species, climate change,alterations of freshwater inflow, coastal land usechanges, and natural disturbances such as storms andfreshets. These stressors interact in important ways.For example, trace metals and organic contaminantshave been shown to affect the quantity and quality ofalgal production in enriched waters (Breitburg et al.,1999). Conversely, eutrophication-induced oxygenstresses influence the immunological responses ofmarine animals to toxicants and pathogens (Lenihan etal., 1999). Unfortunately, our scientific and manage-ment institutions are not well aligned to facilitate theintegration of multiple stressors in ecosystem-basedmanagement. Scientific subcultures, as maintainedby journals, societies, and conferences, tend tofocus on one issue (e.g. toxins, wetlands, nutrients,fisheries, hydrology) or on one biotope (estuaries,rivers and streams, forests, agriculture, and urbanenvironments). At best, management is generally


Fig. 4. Organizational chart of the Chesapeake Bay Program.

integrated only at higher levels and not very effectivelyat the technical levels. For example, in the ChesapeakeBay Program technical subcommittees of the Imple-mentation Committee (Fig. 4) operate more-or-lessindependently.

A major challenge in both regions is the integrationof environmental and fisheries management, especiallybecause an important goal in both of these environ-mental restoration programs is the improvement andprotection of living resources. Recently, the effects offishing have received much attention as a major cause ofcoastal ecosystem degradation (Jackson et al., 2001).Cascading, top-down effects of selective removal ofpredators, heavy mortality of species included in inci-dental bycatch, and physical effects of resource extrac-tion (e.g. bottom trawling in Louisiana and oysterdredging in the Chesapeake Bay) all may have signifi-cant consequences. However, it is not particularly help-ful to stress the primacy of fishing effects in comparisonto other stressors (Boesch et al., 2001a,b), particularlyin the two ecosystems in question.

Although it is generally thought that environmentaldegradation (hypoxia and other effects of eutrophica-tion and wetland and other habitat modification) hasdiminished the capacity of these ecosystems to sustainhealthy fisheries, this relationship is in fact very poorlyquantified or understood in both cases. Yet, unravel-ing the interrelations is essential for ecosystem-basedmanagement and effective restoration. Comparisons of

recent and historic composition of fish caught in trawlson the Louisiana inner continental shelf (Chesney andBaltz, 2001) and Lake Pontchartrain (O’Connell et al.,2004) illustrate the point. Shrimp trawling, eutrophica-tion and hypoxia increased between the earlier periodof the record to the present. In both cases the catch-per-unit-effort (CPUE) of several species of bottomdwelling fish has declined, while the CPUE of certainpelagic, plankton feeders has increased (Table 3). Towhat degree is this a result of bycatch mortalities orthe effects of trawling on bottom sediments, nutrientenrichment or hypoxic stress? As a step in the direc-tion of integrated management of the environment andfisheries,Haas et al. (2004), after examining the rela-tionship between marsh edge and growth and survivalof juvenile brown shrimp (Farfantepenaeus aztecus),argued that management should be extended from thetraditional protection of the spawning stock throughcatch regulations to protection of estuarine life stagesthrough habitat conservation and restoration.

In these two regions and throughout the world, envi-ronmental management cannot be conducted detachedfrom the pressures of socioeconomic development.The economic importance of agricultural productionin the upper Mississippi Basin and the role of theregion in the global food supply are potent forces thatconstrain the options for controlling nutrient inputsinto the Gulf (Turner and Rabalais, 2003). Similarly,accommodating population growth and land develop-


Table 3Changes in the relative abundance (catch per unit effort) in trawl fishery bycatch species off the Louisiana Coastal Area between 1933 and 1989studies (Chesney and Baltz, 2001)

Species Water-column distribution Relative CPUE

1933 1989

Anchoa mitchelli (bay anchovy) Pelagic 29.9 55.7Brevoortia patronus (Gulf menhanden) Pelagic 14.1 26.9Cynoscion arenarius (sand seatrout) Demersal 25.1 17.7Micropogonias undulatus (Atlantic croaker) Demersal 207.4 16.0Arius felis (sea catfish) Demersal 15.1 10.6Leisostomus zanthurus (spot) Demersal 8.3 4.4Polydactylus octonemus (Atlantic threadfin) Nektonic 8.7 1.8Etropus crossotus (fringed flounder) Demersal 3.8 1.7Bairdiella chysura (silver perch) Demersal 4.1 1.6Trichiurus lepturus (cutlassfish) Epi-demersal 11.6 1.5Trinectes maculatus (hogchoker) Demersal 7.2 0.7Selene setapinnis (Atlantic moonfish) Epi-demersal 8.3 0.6Menticirrhus americanus (Southern kingfish) Demersal 4.1 0.6Stellifer lanceolatus (star drum) Demersal 30.6 0.3Peprilus burti (Gulf butterfish) Nektonic 4.3 0.1

ment in the expanding information economy of theMid-Atlantic region present challenges for ChesapeakeBay restoration (Boesch and Greer, 2003). Moreover,restoration of delta wetlands has to contend with therealities of providing flood protection, navigationalaccess and oil and gas extraction. A variety of scien-tific approaches help illuminate these relationships, e.g.the agricultural economic modeling conducted in theGulf of Mexico integrated assessment (CENR, 2000) orthe economic-land use-watershed models that projectwater quality changes in the Patuxent subestuary of theChesapeake (Costanza et al., 2002). However, robustecological-socioeconomic models capable of guidingcoastal ecosystem management and social develop-ment toward a harmonious future remain a distantobjective.

4.2. Sustainability

The state of Louisiana’s grand vision for address-ing wetland loss was entitled “Coast 2050: Towarda Sustainable Coastal Louisiana” (Louisiana CoastalWetlands Conservation and Restoration Task Force,1998) and the LCA Ecosystem Restoration Study (U.S.Army Corps of Engineers, 2004) mentions “sustain-ability” or “sustainable” no fewer than 63 times. Sus-tainability is used to refer to the coastal ecosystem,habitats, wetlands, resources, geomorphic features,landscapes, deltaic functions, restoration approaches,

and even the regional economy. Interestingly, theChesapeake 2000 Agreement, although admittedly amuch shorter document, mentions sustainability onlythree times, all in the context of land uses (ChesapeakeBay Program, 1999).

It is no surprise, with the rapid and seemingly irre-versible changes to the coastal landscape of Louisiana,that the public, policy makers, and managers wouldseek sustainability. However, there are limits to achiev-ing a permanent, static solution in such a clearlydynamic ecosystem. Indeed, if anything dramaticchange has been the secret to success for the Missis-sippi Deltaic Plain. The LCA plan seems to recognizethis in its critical needs assessment criteria, whichinclude restoring fundamentally impaired deltaic func-tions through river reintroductions and preserving geo-morphically important landforms, in addition to pre-venting future land loss and protecting vital socioe-conomic resources. Furthermore, the plan specificallytargets restoration activities that could be sustained inthe face of relative sea-level rise by introducing sedi-ments from the Mississippi River.

Even though the Chesapeake Bay Program has notas explicitly addressed sustainability, the concept isimplicit in many of its commitments. Objectives forwater quality improvements through reduction in nutri-ent and sediment loadings have long included thenotion that once these goals are achieved they will bemaintained (targeted loadings would be capped) even in


the face of population growth and development. Manyof the Program’s commitments to sound land use andstewardship and community engagement were devel-oped to address sustainability. Achieving sustainableyields has long been a stated, but seldom achieved, goalof fisheries management and managing harvest levels tomaintain the “stability” of living resources is an explicitexpectation of the Chesapeake 2000 Agreement. Oneoutcome of the Agreement’s call to “manage the bluecrab fishery to restore a healthy spawning biomass,size and age structure” has been bi-state agreement onfishing pressure reductions necessary to ensure moresustainable exploitation (Bi-state Blue Crab AdvisoryCommittee, 2001).

Resilience is not at all mentioned in either in theLCA Study or in the Chesapeake 2000 agreement, butcould provide a very powerful restoration objective forboth cases. The journalist TomHorton (2003)devotesa whole chapter of his semi-popular book “Turning theTide: Saving the Chesapeake Bay” to resilience. Hortonmakes the point that the Chesapeake Bay has lost muchof its resilience in maintaining its function and recover-ing quickly from disturbances, such as floods and otherclimatic extremes because of human-induced changesnot only in the bay but through out the watershed. Heidentifies as primary culprits the reduced coverage andincreased fragmentation of forests; the loss of wetlands;the development and hardening of shoreline; the degra-dation of benthic communities including submersedgrasses, oysters, and sediment dwelling organisms; andt owfl ores s arel osto stemi ectso rginsa

akee withi oret ce,a thatm ,t , hasc id,c fiftyy ider

restoration of this ecosystem not as a linear process,but as one that involves reshaping the stability domainof the present system to achieve another system statethat has the desirable properties that Horton writesabout. One would expect this restored ecosystem tobe “healthier” in terms of its vigor, organization andresilience (Mageau et al., 1995; Boesch, 2000).

Resilience could also be an important managementobjective for coastal Louisiana ecosystem restoration.How might restoration of wetlands and riparian forestsin the river basins improve the resilience of the coupledbasin-shelf to seasonal hypoxia? What approaches tocoastal wetland and barrier island restoration are mostresilient to hurricanes and other extreme events? Howmight river reintroductions be designed and managedto promote the “self-design” of wetlands, which areresilient in the face of subsidence and sea-level rise?

Defining the requirements for sustainabilityinvolves making predictions about the future that gobeyond an understanding of present conditions or evenreconstructing the changes that led to the degradationof an ecosystem. However, developing predictionsbased on thorough knowledge of past changes in theecosystem, present functions and trends, and modelsthat incorporate effects of alternate managementactions can provide powerful perspectives on whatCarpenter (2002)called “the long now” and, thereby,on the requirements for sustainable solutions. To acertain degree, the strategic models developed fordetermining required reductions in nutrient loadingso onf ver,t timeh nter-g gedd wth,a nnotf plep nceso r thel fors

4

s then gr age

he blockage of rivers to migratory fish. Water nows more rapidly from the landscape, carrying mediment and nutrients. Furthermore, these loadingess effectively attenuated by nontidal wetlands, mf which have been lost. Also, the estuarine ecosy

tself has a diminished capacity to modulate the efff these loadings because of impairments at its mand in its benthic realm.

Put in terms of resilience theory, the Chesapecosystem has transitioned to a new system state

ts own stability basin—one characterized by murbid conditions, phytoplankton-microbe dominannd less efficient support of upper trophic levelsay be quite resistant to change (Fig. 2). As a result

he broader ecosystem, including the watershedonsiderably different resilient properties that it dertainly compared to pre-colonial times, and evenears ago. It might, therefore, be useful to cons

r estimating the effects of restoration featuresuture wetlands embody this approach. Howehese models are typically constrained by shortorizons (generally subgenerational rather than ienerational) and limited consideration of unmanarivers, such as climate change, population grond socioeconomic development, such that they ca

ully address sustainability. Development of multilausible scenarios that illustrate the consequef both management and societal decisions ove

ong term may help illuminate the requirementsustainability (e.g.Boesch and Greer, 2003).

.3. Precaution

The Chesapeake 2000 Agreement incorporateotion of precaution explicitly with regard to livinesources management, indicating: “we will man


harvest levels with precaution to maintain their healthand stability and protect the ecosystem as a whole”.Precaution or precautionary are mentioned over 50 timein the fisheries ecosystem plan (McBride and Houde,2004) in which the “precautionary approach” is definedas “a type of fishery management that exercises pru-dent forethought to avoid undesirable outcomes withrespect to stock status, yield potential, or profitability.This approach accounts for changes in fisheries systemsthat are only slowly reversible, difficult to control, notwell understood, and subject to changing environmentand human values”.

Precaution is also implicit in other Chesapeake2000 management commitments. For example, regard-ing potentially toxic chemical contaminants it states:“Through continual improvement of pollution preven-tion measures and other voluntary means, strive for zerorelease of chemical contaminants from point sources”.Much like the original development of the precaution-ary principle for North Sea chemical discharges, thiscommitment is based on strong risk aversion.

Precaution has been less explicitly been consideredas an integral element of management for the Louisianacoastal ecosystem. Given the massive legacy of theunintended consequences of agricultural development,river management, flood protection, navigation, oil andgas extraction, and fisheries exploitation in this ecosys-tem, it should be more specifically addressed. Whilemany of the restoration measures considered in theLCA Plan are designed to correct for or reverse theu mayh phasi unta tionf cients sses,w lotp rm,l Sci-e onr : (1)p linec onalm , ande liticalc

s int the

ecosystem rather than consideration of a new addi-tion or human activity, the precautionary approach isusually being applied in the inverse of how it was origi-nally proposed for North Sea dumping, i.e., what are theconsequences of not correcting a problem. However, aconventional challenge for precautionary managementcurrently exists regarding the possible introductionof a nonnative oyster species,Crassostrea ariakensis,into the Chesapeake Bay (National Research Council,2004a). Such an introduction is being proposed by thestates of Maryland and Virginia because this speciesseems to be able to grow well under the environmentalconditions found in the bay and resist lethal diseasesthat currently limit recovery of the nativeC. virginica.Interestingly, the introduction is proposed not only forrevitalization of the fishery, but also for restorationof the role that oysters played in filtering eutrophicwaters, thereby helping to recover the resilience in theecosystem. Extensive research is underway to addresscritical questions in a risk assessment framework, butin the end the decision will be highly dependent onthe level of precaution applied. What is the burdenof proof concerning potentially deleterious effects thatmay be largely irreversible? How will the uncertaintiesbe weighed in the decision? And how do contempo-rary socioeconomic factors affect the determination ofappropriate precaution?

4.4. Adaptation

verye ss-m .,2 ndr 4A beenc ingl CAr duc-t atedi ar-i forf less,i atedt ram(f tionp ec-

nintended consequences of past actions, theyave unintended consequences themselves. The

ng of the LCA Plan seems to take this into accodvancing programmatic authorization for restora

eatures that meet a sorting criterion based on sufficientific and engineering understanding of procehile holding others for additional evaluation, piroject testing, and more detailed study of long-te

arge-scale concepts. Further, the plan calls for ance and Technology Program that would focuseducing uncertainties, including those related tohysical, chemical, geological, and biological baseonditions; (2) engineering concepts and operatiethods; (3) ecological processes, analytical toolscosystem responses; and (4) socioeconomic/poonditions and responses.

Because many of the management challengehese two regions involve undoing changes to

-Adaptive management has been embraced

xplicitly in the Gulf hypoxia Integrated Asseent (CENR, 2000) and Action Plan (Rabalais et al002a,b) and in the LCA Plan for coastal wetlaestoration (U.S. Army Corps of Engineers, 200).daptive assessments of the monitoring haveonducted on completed CWPPRA projects, yieldessons learned that could be incorporated into Lestoration measures. In addition, existing reintroions of river flow into the wetlands have been opern “experimental” modes in which flow rates are ved or pulsed, again producing valuable informationuture design and operation of diversions. Nonethen the draft LCA Plan adaptive management is relego an activity of the Science and Technology ProgU.S. Army Corps of Engineers, 2004), rather thanundamentally ingrained in the ecosystem restorarogram itself. While its emphasis on explicit exp


tations, monitoring, and learning provides an overallphilosophical model and framework for integratingmodeling, monitoring and research, adaptive manage-ment does have its practical limits for such a largeecosystem as coastal Louisiana, where many poten-tial interventions are costly and relatively irreversible.For example, although one can certainly learn valuablelessons from monitoring the small-scale river diver-sions currently in place in the delta, the expense andsocial dislocations involved in massive river diversionsrequire that they be considered as more than just “exper-iments”.

In contrast to coastal Louisiana and other majorecosystem restoration programs heavily dependent onwater management, such as for the Everglades, SanFrancisco Bay and Sacramento-San Joaquin Delta, andUpper Mississippi River (NRC, 2004b), adaptive man-agement is not an explicit framework or formal processin the Chesapeake Bay Program. However, earlier in itshistory,Hennessey (1994)viewed the Chesapeake BayProgram as a good example of adaptive managementof a large ecosystem in that it has adjusted goals basedon experience and information. On the other hand, I(Boesch, 1996, 2001) noted the Program’s shortcom-ings in emphasis on structured learning, pursuit ofmultiple options in the face of uncertainty, and closeinteraction between models and monitoring that are thehallmarks of adaptive, as opposed to “trial and error”or reactive, management (NRC, 2004b). The applica-tion of adaptive management approaches is discussedia nalm mil-i ts.

st bee lecta n bec or-r andc plicite ctu-a andp TheC ancede arer o-i Stateo 02

asserts: “Throughout the 1980s and 1990s, we madereal progress toward our goals of improving the Bay’swater quality and reducing pollution. A recent analysisrevealed that between 1985 and 2000, phosphorus loadsdelivered to the Bay from all of its tributaries declinedby 8 million pounds per year. Nitrogen loads declinedby 53 million pounds per year”. First, the monitoringresults summarized elsewhere in the report providesscant evidence of actual water quality improvementsin the bay. In addition, the analysis referred to isbased on monitoring of direct point source dischargestogether with unverified model estimates of the moresignificant nonpoint discharges, which assumes of thecomplete and immediate effectiveness of managementpractices applied. Not only is this reliance on modelsdesigned for strategic forecasts in progress assessmentmisleading, as suggested in a front-pageWashingtonPost article (Whoriskey, 2004), but failure to rigor-ously compare loadings via streams and rivers to modelprojections misses adaptive learning opportunities thatcould help refine models, improve monitoring, and,most importantly, reassess the effectiveness of man-agement strategies.

Both models and monitoring are critical to adap-tive management, but, in evaluating 25 adaptive man-agement planning exercises for riparian and coastalecosystems,Walters (1997)found that ongoing mod-eling that strives for ever-increasing detail and com-plexity tended to supplant monitoring, field experimen-tation and the alternate models needed for adaptivem ess-i andf ing”o me-h nsa . TheC odelc elshC aa ret nowb lexh tion.

toe nges,i e ine ms

n the Chesapeake fisheries ecosystem plan (McBridend Houde, 2004), but most Chesapeake Bay regioanagers and scientists, alike, remain largely unfa

ar with adaptive management and its requiremenUnder adaptive management, practitioners mu

xplicit about what they expect and they must colnd analyze information so that expectations caompared with actuality. They must periodically cect errors, improve their imperfect understanding,hange actions and plans. The coupling among exxpectations (from modeling), comparisons with ality (through monitoring), and changed actionslans is the essence of adaptive management.hesapeake Bay Program has extensive and advnvironmental and monitoring programs, but theyelatively weakly linked in either periodic or ongng assessments of progress. For example, af the Bay report (Chesapeake Bay Program, 20)

anagement. Walters also noted that it is “deprngly easy” for scientists to convince themselves,unding agencies, that “fundamental understandf the process or mechanism that they study is soow important for refining models to make predictiobout impacts of ecosystem management policieshesapeake Bay Program has stressed the big multure. In coastal Louisiana multiple, simpler modave been used both for wetland restoration (U.S. Armyorps of Engineers, 2004, Appendix C) and hypoxissessments (Scavia et al., 2004) because these we

he only approaches feasible at the time. Callseing made there for “more sophisticated”, compydrodynamic models should be greeted with cau

The implementation of an adaptive approachcosystem restoration faces many practical challe

ncluding convincing the stakeholders to participatxperiments; sustaining effective monitoring progra


in the face of waning interests and other priorities;interpreting the ambiguous outcomes likely in com-plex and uncontrolled ecosystems; and resistance tochanges in management approaches. Nonetheless, it isit is clear that our understanding, goals and prioritiesdo evolve over time. It stands to reason that embracingsome form of formally adaptive structure would assistin the orderly and effective evolution of ecosystem-based management.

5. Paths forward

Although I admit bias from my experience, whichhas predominantly been in the two ecosystems in ques-tion, I believe that the efforts to restore the Chesa-peake Bay and coastal Louisiana ecosystems presentamong the foremost challenges for science and coastalmanagement in the United States and, thereby, haveimportant implications for addressing the coastal envi-ronmental crises being experienced around the nationand throughout the world. The imposing scales of thesetwo coastal systems and associated watersheds areobviously one reason for my thinking this. The twoecosystems also are confronting a plethora of envi-ronmental challenges—virtually every problem beingexperienced elsewhere and then some—that requireintegrated solutions through ecosystem-based manage-ment. These two systems have been the archetypicalmodels for scientific understanding of estuaries andr esa-p porta ario”f t bed therh per-h osti sys-t city,f hedsw

tiono ow-i ncei anda asedm uirem ctive

scientists, organizations that support science, and deci-sion makers.

• Greater scientific attention should be directed to pro-viding the solutions needed for ecosystem restora-tion. While scientists have been remarkably suc-cessful in documenting the historical changes inthese two coastal ecosystems and in diagnosingthe causes of ecosystem degradation, we are lesswell adept at prescribing solutions. Solution scienceconfronts a scientific culture that offers incentivesfor detachment and disincentives for engagement.Given the urgency of the world’s problems, scientistsmust become more engaged interacting with deci-sion makers and informing the public (Lubchenco,1998; Palmer et al., 2004). Environmental scien-tists should become well versed in the conceptsof integration, sustainability, precaution and adap-tation and seek ways to contribute to their prac-tical application in ecosystem-based management.While it is important that vibrant programs of basic,curiosity-driven research are sustained, sponsorshipof solution science should be greatly expanded.Peer review should be modified to allow innova-tion, but terminate support for superficially appeal-ing research on ineffective solutions. Better integra-tion of research planning, monitoring, assessmentand reporting on conditions is required (Kates etal., 2001). Human health-related research has suc-cessfully fostered excellent science and solution sci-

l forh pro-

• andfor

pleteent

on-blen-

tiveffec-ro-

ees,sess-alsoe atuse

iver deltas, respectively. In the case of the Cheake Bay, the strength of the science, public supnd financial capacity create a “best case scen

or large-scale ecosystem restoration. If it cannoone here, can it be done anywhere? On the oand, coastal Louisiana enigmatically containsaps the nation’s most economically valuable and m

mminently threatened coastal region. And, bothems stretch the imagination, much less the capaor comprehensive management over large watersith multiple jurisdictions of governance.From this review of current status of the restora

f these two coastal ecosystems, I offer the follng suggestions to improve the contributions of scien advancing integration, sustainability, precautiondaptation as practical dimensions of ecosystem-banagement. Acting on these suggestions will reqajor changes in the way business is done by a

ence for many years and can serve as a modenew management-oriented, ecosystem researcgrams.Bridges should be built that cross scientificmanagement barriers to the integration requiredecosystem-based management. While the commerger of scientific disciplines and managemresponsibilities is both unlikely and unwise, ccerted efforts are required to bridge the formidabarriers to effective integration. Providing finacial incentives, e.g. targeted funding for integraresearch and assessments, is likely to be most etive. Broadening interdisciplinary graduate and pfessional training, coalescing technical committand focusing conferences, workshops and asment teams on key integration problems couldhelp. Boundary organizations that are effectivcommunication, translation, and mediation beca


of their credibility, salience and legitimacy (Cash etal., 2003) should be built and sustained. These couldinclude special centers, committees and coalitions.

• More attention should be given to understand-ing and predicting achievable restoration outcomesthat consider possible state changes and ecosystemresilience. Research and assessment should evaluatedegradation tipping points and restoration thresh-olds. Greater support should be provided and insti-tutional arrangements revised to foster predictiveapproaches and provide a solid scientific basis for theselection and maintenance of achievable and desir-able outcomes, which effectively provide desiredservices in the combination of conserved, restoredand invented ecosystems that will characterize ourhuman-dominated coasts of the future (Palmer et al.,2004).

• Science should improve its capacity to characterize,if not quantify, uncertainty in assessments and pre-dictions and to effectively communicate this uncer-tainty to managers and the public. Improvements inthis area are critical if the precautionary approach isto move beyond rhetoric and opinion into practicalapplication.

• Modeling, observations, and research should befully integrated to facilitate adaptive management.Development and comparisons of multiple modelsshould be encouraged; exclusive reliance on com-plex, monolithic models should be avoided. Progress

anndter-eynd

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B the4.

B on-ergy22.

B ton,D.,tedica

Bi-State Blue Crab Advisory Committee, 2001. Taking Action for theBlue Crab: Managing and Protecting the Stock and its Fisheries.Chesapeake Bay Commission, Annapolis, MD. Available online:http://www.chesbay.state.va.us/BBCACReport-final.pdf.

Boesch, D.F., 1996. Science and management in four U.S. coastalecosystems dominated by land-ocean interactions. J. CoastalConserv. 2, 103–114.

Boesch, D.F., 1999. The role of science in ocean governance. Ecol.Econ. 31, 189–198.

Boesch, D.F., 2000. Measuring the health of the Chesapeake Bay:toward integration and prediction. Environ. Res. 82, 134–142.

Boesch, D.F., 2001. Science and integrated drainage basin-coastalmanagement: the Chesapeake Bay and the Mississippi Delta.In: von Bodungen, B., Turner, K. (Eds.), Science and Inte-grated Coastal Management. Dahlem University Press, Berlin,pp. 37–50.

Boesch, D.F., Josselyn, M.N., Metha, A.J., Morris, J.T., Nuttle, W.K.,Simenstad, C.A., Swift, D.J.P., 1994. Scientific assessement ofcoastal wetland loss, restoration and management in Louisiana.J. Coastal Res. 20, 1–103 (special issue).

Boesch, D.F., Brinsfield, R.B., Magnien, R.E., 2001a. ChesapeakeBay eutrophication: scientific understanding, ecosystem restora-tion, and challenges for agriculture. J. Environ. Qual. 30,303–320.

Boesch, D., Burreson, E., Dennison, W., Houde, E., Kemp, M.,Kennedy, V., Newell, R., Paynter, K., Orth, R., Ulanowicz, R.,2001b. Factors in the decline of coastal ecosystems. Science 293,1589–1590.

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Boynton, W.R., Garber, J.H., Summers, R., Kemp, W.M., 1995.Inputs, transformations, and transport of nitrogen and phospho-rus in Chesapeake Bay and selected tributaries. Estuaries 18,285–314.

an,ilityion ofnog-

onarine

the

omsys-

s-for091.rshedpo-t/

to theion

should be assessed or verified by observationsthe relationships between model projections aobservations should be used to assist in the inpretation of observations (whether and why thdeviate from projections), refinements of models aimprovements of the observing systems.

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Scientiﬁc requirements for ecosystem-based management in the … CB... · 2020-01-06 · Although frameworks exist for integration of management objectives in both regions,