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ANRV357-EG33-03 ARI 15September2008 15:34
ANNUAL Further Restoration Ecology:
REVIEWS
Click here for quick links to Interventionist Approaches
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• Other articles in this volume for Restoring and Maintaining
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• Our comprehensive search Ecosystem Function
in the Face of Rapid
Environmental Change
Richard J. Hobbs and Viki A. Cramer
School of Environmental Science, Murdoch University, Murdoch, Western Australia 6150,
Australia; email: R.Hobbs@murdoch.edu.au, V.Cramer@murdoch.edu.au
Annu. Rev. Environ. Resour. 2008.33:39–61 KeyWords
First published online as a Review in Advance on climate change, complex ecosystems, ecological restoration, priority
July 29, 2008 setting, threshold
TheAnnualReviewofEnvironment and Resources Abstract
is online at environ.annualreviews.org
by Universidade de Sao Paulo (USP) on 02/22/11. For personal use only.This article’s doi:Restoration ecology provides the conceptual and practical frameworks
10.1146/annurev.environ.33.020107.113631 to guide management interventions aimed at repairing environmental
c
Annu. Rev. Environ. Resourc. 2008.33:39-61. Downloaded from www.annualreviews.orgCopyright 2008 by Annual Reviews.damage.Restorationactivitiesrangefromlocaltoregionalandfromvol-
All rights reserved unteer efforts to large-scale multiagency activities. Interventions vary
1543-5938/08/1121-0039$20.00 froma“donothing”approachtoavarietyofabioticandbioticinterven-
tionsaimedatspeedinguporalteringthecourseofecosystemrecovery.
Revised understanding of ecosystem dynamics, the place of humans in
historicecosystems,andchangedenvironmentalsettingsowingtorapid
environmental change all impact on decisions concerning which inter-
ventionsareappropriate.Keyissuesrelatingtoecosystemrestorationin
a rapidly changing world include understanding how potentially syner-
gisticglobalchangedriversinteracttoalterthedynamicsandrestoration
of ecosystems and how novel ecosystems without a historic analogue
should be managed.
39
ANRV357-EG33-03 ARI 15September2008 15:34
WHATISECOLOGICAL
Contents RESTORATION?
INTRODUCTION.................. 40 Ecological restoration can be described as
WHATISECOLOGICAL the process of assisting the recovery of dam-
RESTORATION?................. 40 aged, degraded, or destroyed ecosystems (8).
INTERVENTION:WHEN, “Restoration” is one of a stable of “re” words
WHERE,ANDHOWMUCH?... 42 that have come to be associated with some
TYPESOFINTERVENTION....... 43 sort of environmental repair. Some of the more
NoIntervention ................... 44 commonly used terms include: rehabilitation,
Abiotic Interventions............... 45 reclamation,recreation,remediation,revegeta-
Biotic Interventions................ 46 tion, and reconstruction. Allied terms also in-
Broader-Scale Interventions ........ 48 clude ecological engineering (9).
ONE-OFFORONGOING Traditionally, restoration has been viewed
INTERVENTIONS?.............. 48 primarily as a means to reset the ecological
SETTINGPRIORITIES............. 49 clockandreturnanecosystembacktosomepast
RESTORATIONECOLOGYINA state, often what was there prior to disturbance
RAPIDLYCHANGING or damage [e.g., (10, 11)]. Other activities that
WORLD.......................... 50 aimtorepairdamage,butnotnecessarilyreturn
CONCLUSIONS.................... 54 the historic ecosystem, have been termed reha-
bilitation or, whenanalternativesystemorland
use is aimed at, reallocation (10). There is in-
creasing recognition that many forms of repair
INTRODUCTION activity are needed that cover a variety of aims,
includingrestoringecosystemfunctionandser-
Restoration ecology is a relatively young sci- vices as well as particular sets of species (12).
ence that aims to provide the scientific un- Hence,restorationcoversawiderangeofactiv-
derpinnings to the management and repair of ities ranging from the purist perspective, which
damaged ecosystems. The practice of ecologi- seeks to return an exact copy of the preexisting
cal restoration is becoming an increasingly im- ecosystemandallitsspeciestoadegradedarea,
portant tool in humanity’s attempt to manage, toless ambitiousbutnolessworthygoalstore-
conserve, and repair the world’s ecosystems in turnadegradedareatosomesortoffunctioning
thefaceofanincreasinglegacyofenvironmen- ecosystem,tobasicaimsofreturningsomesort
tal damage (1, 2). The field has seen a dramatic of vegetation for erosion control or food and
by Universidade de Sao Paulo (USP) on 02/22/11. For personal use only.increase in interest from academic ecologists infiber production.
thepastdecade(3)asattemptsaremadetomove There is a wide range of circumstances in
Annu. Rev. Environ. Resourc. 2008.33:39-61. Downloaded from www.annualreviews.orgtoward a sound conceptual underpinning forwhich restoration is being attempted around
thescience(4–7).Suchaconceptualframework the world. The scale of operation ranges from
allowsforgeneralizationstobemadefrompar- very local to regional and national, and the
ticular studies and restoration projects and for types of work undertaken vary from local
lessons learned in one place to be more readily volunteers working with hand tools to large
transferred to other situations. Restoration is, industrial processes involving earthmoving
byits nature, largely an interventionist activity. machinery.
In the light of recent conceptual developments For instance, we see individuals and local
in restoration ecology, we discuss the different communities in cities and rural areas engag-
typesofinterventionthatareusedinrestoration ing in restoration of local preserves, which
andthenconsidertheseactivitiesinthecontext have been invaded by aggressive nonnative
of ongoing rapid environmental change. weedy species, or waterways, which have been
40 Hobbs · Cramer
ANRV357-EG33-03 ARI 15September2008 15:34
turned more into drains than living ecosys- Iraq, which had been previously drained
tems. These activities are often very hands- by the Hussein regime to displace marsh
on endeavors, engage people in voluntary Arabs, in order to both restore the
repair of damaged ecosystems, and can engen- ecology of the wetlands and allow a
der a reconnection with nature, especially in people to return to their traditional way
urban environments [e.g., (11, 13, 14)]. Such of life (22)
activities can be highly successful in both eco-
logical and social terms, and in some cases, a Restoring plant cover in arid lands in
collection of local activities can be brought to- Africa and elsewhere that have been de-
gether to form broader restoration and conser- graded through overgrazing, overuse, or
vation strategies and visions for a whole region neglectduringwarandfamine,inorderto
(15). both stabilize the environment and pro-
Inadditiontotheselocalrestorationefforts, vide livelihoods, food, and fuel for huge
there are a great many projects run by commu- numbersofpeople(23–25)
nities, government agencies, and nongovern- Restoringriversandwaterflowsinsouth-
mental organizations (NGOs), which, for var- ern Florida to both allow for adequate
ied reasons, aim to restore either the structure flood control and feed the internation-
or function (or both) of systems that have been ally important Everglades National Park
degraded or modified to a greater or lesser ex- (26, 27)
tent. These projects range in size from a few
hundred square meters to hundreds of thou- Restoring fire regimes in forests in the
sands of square kilometers and include the fol- western United States to both return the
lowing: forest to a different structure and pre-
Restoring fire and grazing regimes to vent continuing catastrophic forest fires
prairieremnantsintheMidwestofNorth (28, 29)
America (16, 17)
Restoring surface-mined areas in forests Theabovesetofexamplesprovides a flavor
in southwestern Australia to return a for- of the range of activities encompassed within
est ecosystem to the area and at the same restoration. Table 1 indicates the types of in-
time protect drinking water supplies and tervention likely to be needed in each case,
other functions essential in multiple-use together with the types of people likely to
forests (18) undertake the restoration. Some involve very
Restoring rainforest ecosystems in areas hands-onlocalactionbyenthusiasticandhard-
by Universidade de Sao Paulo (USP) on 02/22/11. For personal use only.formerly deforested in Costa Rica, in or-working volunteers with a conservation focus.
der to increase the area of valuable habi- Others involve local people working to turn
Annu. Rev. Environ. Resourc. 2008.33:39-61. Downloaded from www.annualreviews.orgtat and at the same time provide im-arounddecadesofdegradationtoalleviateboth
portant functions such as ensuring clean environmental degradation and serious human
water supply (19, 20) deprivation.Othersinvolveamuchmoremech-
Restoring woodland cover to large ar- anizedapproachwithlargemachineryinvolved
easofScotland,whichhaveuntilrecently and work at very broad spatial scales: Many
been maintained as open areas for graz- of these are multimillion dollar projects led
ing and sport shooting by a landed elite, by government. The scale of focus, resources
in order to both increase the area of an available, and objectives vary greatly across this
important ecosystem and wildlife habitat range.Mostoftheseactivitiesinvolvesomesort
andtoprovideemploymentandopportu- of interventional management. In this review,
nity for local communities (21) weexaminethedifferenttypesofinterventions
Restoring waterflows to the used in restoration, using the projects listed
Mesopotamian Marshes in southern above as illustrative examples.
www.annualreviews.org • Restoration Ecology 41
ANRV357-EG33-03 ARI 15September2008 15:34
Table 1 Examples of restoration projects conducted at local or regional scales, with representative examples of abiotic and
a
biotic interventions
Restoration Spatial Abiotic Typeofpeople
b
project scale interventions Biotic interventions involved Degreeofsuccess
Prairie Local · Reinstating · Altering Community Successful if ongoing
remnants, historic fire grazing intensities groups managementapplied
Midwest regime · Removalofnonnative
United States shrub species
Surface-mined Local · Soil ripping · Returnofplant Mining Successful return of
lands in · Fertilizer communityviatopsoil company forest ecosystem subject
southwestern addition return, direct seeding, employees to ongoing adaptive
Australia and planting management
· Control of herbivory
Rainforest in Local — · Addition of structural Community Partial return of forest
Central and vegetation components groups ecosystem, forest
South America structure reestablished
Woodlandsin Local · Reduction of fire · Control of grazing by NGOs, Successful regeneration
Scotland frequency deer and other community of tree species
herbivores groups
Mesopotamian Regional · Reinstatement of — National Successful rehydration of
Marshes water flows into management someareas; ecosystem
marshes body, local response still developing
community
Arid lands Local/ · Provision of · Reduction of grazing Local managers, Successful redevelopment
(Africa and regional physical barriers pressure community of woody vegetation and
elsewhere) to slow water flow groups, NGOs pasture in some areas
· Creation of
microcatchments/
imprinting
Rivers in Regional · Removalof — Regional Successful local
southern channelization management restoration of river
Florida and barrier gates bodies reaches; success of
· Reinstatement of broader regional project
river meanders still to be determined
Fire regimes in Regional · Reinstatement of · Structural alteration State and federal Still to be determined
by Universidade de Sao Paulo (USP) on 02/22/11. For personal use only.southwesternhistoric frequentof vegetation to alteragencies
United States low-intensity fire fuel distributions
Annu. Rev. Environ. Resourc. 2008.33:39-61. Downloaded from www.annualreviews.orgaSee text for literature references for particular projects.
bNote: Success needs to be determined against the specific goals set for particular projects.
INTERVENTION:WHEN, other words, we need to understand how it
WHERE,ANDHOWMUCH? workedbeforeitwasmodifiedordegradedand
Deciding on what type of intervention, if any, then use this understanding to reassemble it
is required for the effective restoration of an andreinstateessentialprocesses.Ithasbeenre-
ecosystem (or particular components or pro- cently suggested that restoration often rests on
cesses) presupposes a clear understanding of a series of myths, which are based on assump-
how the ecosystem works and what the out- tionsregardinghowsystemsworkandwhatthe
comes of the intervention are likely to be. In outcome of particular interventions might be
42 Hobbs · Cramer
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