ecological resilience: is it ready for operationalisation in forest management?

Chapter

ECOLOGICAL RESILIENCE: IS IT READY FOR

OPERATIONALISATION IN FOREST MANAGEMENT?

Gerardo Reyes1,2* and Daniel Kneeshaw

2

1Department of Interdisciplinary Studies, Lakehead University,

Orillia, Ontario, Canada 2Centre for Forest Research, Department of Biological Sciences,

University of Quebec in Montreal, Montreal, Quebec, Canada

ABSTRACT

Given the physiographic variability, variation in socio-political landscapes, and

differences in connectedness of people and communities associated with boreal forest

ecosystems, approaches to forest management that are flexible enough to accommodate

this variation are needed. Moreover, to ensure sustainable forest resource use, we need to

embrace the inherent complexity of boreal forest ecosystems rather than eliminate it, and

be prepared to adapt and adjust as environmental conditions change. While ecological

resilience may be a useful forest management objective to this end, developing general

guidelines to integrate it into practice remains elusive. We address a number of questions

often posed by managers when attempting to include ecological resilience into forest

management planning. Our goal is to determine if the theoretical foundation of ecological

resilience is sufficiently developed to provide a general framework that can be applied for

boreal forest management.

Keywords: Boreal forests, ecological resilience, stability and change, adaptation, forest

ecosystem management

* E-mail : [email protected]; [email protected].

Gerardo Reyes and Daniel Kneeshaw 2

1. INTRODUCTION

Given the overwhelming environmental, social, and economic importance of forests to

humankind, preoccupation is growing for promoting the sustainable use of forest ecosystem

resources. Because of expected rapid changes in global conditions over the next century

(Sokolov et al. 2009) and the potential consequences of these changes to our well-being, it is

imperative that we develop and implement forest management strategies that ensure forests

will continue to provide us with needed resources and services. Ecological resilience, an

ecosystem’s ability to re-organize and adapt to disturbance or environmental change without

shifting to an undesirable alternative state (Holling 1973, Gunderson 2000), is a concept that

has been proposed to help us to achieve this objective.

Ecological resilience was conceptualized to help explain unexpected and nonlinear

dynamics observed in complex adaptive systems (Holling 1973, Gunderson and Holling

2002), thus providing a theoretical foundation towards spatio-temporal understanding of how

boreal forest ecosystems may respond to any changes in climate, natural and anthropogenic

disturbances, invasive species, resource utilisation, and so forth. Managing for ecological

resilience is said to promote sustainability by enhancing a forest ecosystem’s adaptive

capacity (Gunderson 2000, Allen and Holling 2010), defined as the magnitude of an

ecosystem’s component species’ ability to respond and adapt to disturbance or change before

collapsing and shifting to a new stability domain, even as the shape or breadth of the domain

changes (Figure 1). In other words, maintaining or improving the ability of species within

ecosystems to respond to episodic disturbances or gradual change will improve an

ecosystem’s chance of avoiding progression towards an unwanted ecological state (Holling

1973, Walker et al. 2004). Thus, forest ecosystems adapted to natural as well as imposed

anthropogenic disturbance regimes will have greater capacity to re-organize and retain

desired characteristics and functions, and by consequence be more resilient. Central to this

tenet is that while post-disturbance conditions in resilient ecosystems are not expected to be

exactly like those that existed prior to disturbance, as structural and compositional changes

occur, the same critical processes driving the system are upheld (e.g., photosynthetic capacity,

nutrient cycling, disturbance regime, etc.). Changes in critical processes can drive an

ecosystem into a new stability domain and thus it is imperative that we focus our attention on

understanding their roles in ecosystem maintenance.

Along with the direct changes to forest structure and natural ecological processes caused

by forest management, climate change presents new and unique challenges that will make

sustainable management of boreal forest ecosystems far more difficult to achieve given the

potential for it to interact with processes such as nutrient and hydrological cycling,

disturbance regimes, pollination, etc. (Bonan 2008, Berggren et al. 2009, Huntington et al.

2009). Even now, fundamental changes to environmental conditions are occurring at an

unprecedented rate (Bentz et al. 2010, Kilpeläinen et al. 2010, Fettig et al. 2013) and we are

uncertain about the nature, magnitude, and timing of the effects. Given this uncertainty, an

adaptive approach for boreal forest ecosystem management is essential. To this end, the idea

of making forest ecosystems resilient to these challenges is certainly appealing. However,

operationalizing the concept; i.e., actively managing for resilience has a number of stumbling

blocks that require attention.

Ecological Resilience 3

Figure 1. Ball and cup conceptual model of ecological resilience and ecosystem state change. Balls

represent different stable ecological states, each within a domain of attraction controlled by a unique set

of processes. A threshold point is exceeded when a disturbance or change is so intense, severe, or

frequent that an ecosystem is driven into a qualitatively different stable ecosystem state and controlled

by a different set of ecological processes. In this example, grassland, boreal forest, and heathland

ecosystems are shown. In (A) ecological states shift into alternate stable states when disturbances of

sufficient magnitude or gradual changes drive them beyond ecological threshold points and into

different domains of attraction; (B) the domain itself can change in depth or width over time due to

slow changes in controlling processes (e.g., climate, acid rain), also potentially causing shifts in

ecological state as well as changing an ecosystem’s overall resilience. Red arrows with solid lines

indicate changes within an ecosystem’s natural range of variation. These shifts may be caused by

natural disturbances such as fire or insect outbreaks for which ecosystem components have developed

adaptations to; i.e., the disturbances have historical precedents. Red arrows with dotted lines indicate

that restoration effort may be required if attempting to shift a system from an unwanted ecological state

back into another.

Modified from Gunderson (2000)

Our purpose here is to examine the applicability of ecological resilience as a management

option in boreal forest ecosystems. We address a number of questions directly related to

‘putting the concept on the ground’ for a hypothetical forest management unit. Ultimately, we

wish to determine if the theoretical foundation of ecological resilience is developed enough to

provide a general framework that can be applied for any boreal forest management unit.

A

B


2. INTEGRATING ECOLOGICAL RESILIENCE

INTO FOREST MANAGEMENT

Those involved with boreal forest management decisions usually raise questions such as:

i. For what components of an ecosystem should we build ecological resilience?

ii. What do we need to know to manage for ecological resilience?

iii. At what spatio-temporal scales should we focus our management efforts? and

iv. How do we determine if a system is resilient or not?

Proponents of resilience thinking have responded by stating that:

managing for ecological resilience requires:

i. clearly defined stakeholder objectives;

ii. knowledge of critical processes and drivers that promote ecosystem stability or

ecosystem change;

iii. knowledge of the ecological impacts of cultivating, harvesting, or using various

ecosystem resources or services at multiple scales; and

iv. indicators of the adequacy of resilience via proxies such as biological diversity,

structural heterogeneity, response diversity, and ecological redundancy.

(Fischer et al. 2006, Campbell et al. 2009, Thompson et al. 2009)

For the remainder of this section, we address each of the above questions in relation to

the responses in more detail.

2.1. For What Components of an Ecosystem Should We Build Ecological

Resilience?

A starting point for operationalising ecological resilience is for stakeholders to determine

what objectives to manage for. The question of ‘resilience of what to what?’ (Carpenter et al.

2001) forces managers to clearly define objectives for the entire forest management unit and

explicitly specify their relative importance and spatio-temporal impacts across the landscape.

This can include managing for timber supply, maintaining biodiversity or old-growth forest,

provisioning of water, or providing opportunities for recreational activities. However, it

should be recognized that managing for one desired aspect of an ecosystem may reduce

resilience of another. This apparent paradox stems from what Holling and Meffe (1996)

called a ‘command and control’ approach to managing resources. They note that managers

have simplified ecosystems to maximize the production of a desired resource; and that it this

simplification that reduces the adaptability of a system and thus the resilience of its non-

targeted components.

When entire forest management units are managed for only one purpose, tradeoffs are

inevitable. We cannot maintain resilience for everything everywhere because of fundamental

differences in species’ life history requirements, feedbacks and interactions among species,

and conflicting stakeholder interests. For example, management plans may include provisions


to enhance white-tailed deer (Odocoileus virginianus) habitat. Large herd sizes provide

greater opportunities for hunters and naturalists but also result in heavy browsing damage to

regenerating commercial tree species (Rooney and Waller 2003). Moreover, improving

hunting opportunities entails having a mix of favorable habitat types across the landscape that

includes conifer forest cover for shelter during winter, an abundance of clearings that provide

herbaceous plants, forbs, and browse for deer to forage, as well as maintaining logging roads

for human access (Voigt et al. 1997). Conversely, protecting pine marten (Martes americana)

populations in the same forest management unit may require maintaining large tracts of intact

mature mixed-coniferous forest containing spruce (Picea spp.), fir (Abies spp.), or cedar

(Thuja occidentalis), and limiting the fragmentation across the landscape that favours deer

(Watt et al. 1996). Many other associated plant and animal species also draw benefits or are

negatively impacted by conditions that promote elevated deer population densities (de Calesta

1994, Gill and Beardall 2001). Extremely high population densities have, for example, shifted

the forest state on Anticosti Island from a balsam fir (Abies balsamea) to white spruce (Picea

glauca) dominated forest with concomitant losses or decreases of many herbaceous species

palatable to deer (Potvin et al. 2003, Morissette et al. 2009) . Managing for a single resource

invariably reduces habitable conditions for other elements in the ecosystem and may be a

critical driver for shifting ecological states.

2.2. What Do We Need to Know to Manage for Ecological Resilience?

Whether our desire is to simply maintain a functioning forest ecosystem or to maintain a

specific type of forest ecosystem, building ecological resilience entails identifying the critical

processes that drive the ecosystem (Table 1). Species and ecosystems are adapted to

ecological processes that have historical precedents (Peterson 2000, Read et al. 2004,

Johnstone et al. 2010). Retaining these processes is thus an approach that can be proactively

used to maintain ecological resilience. This is in fact, the original premise behind the

Emulating Natural Disturbance (END) concept (Gauthier et al. 2008). Moreover, if the focus

is centered on emulating processes rather than patterns END would escape some (but perhaps

not all) of the critiques of managing for past patterns in a changing environment.

Understanding the natural variability in processes and species adaptations to them can

identify the type and range of processes that will maintain the stability of a desirable state, as

well as those that will lead to unwanted ecosystem state changes.

Natural processes that can lead to an ecosystem state change includes paludification,

which results in the conversion of conifer forests in to peat bogs over time (Lavoie et al.

2005). The process can be magnified by human activity when dominant or correcting

processes are not understood. For example, severe fires that burn into the moss layer can

reduce or reverse paludification whereas partial or less severe disturbances such as windthrow

or senescence (e.g. pathogen caused tree mortality) that do not disturb the soil (moss) layer

accelerate the process. Consequently, the blanket approach of using harvesting that protects

soils and advance regeneration (Leblanc and Pouliot 2011) creates conditions favourable for

stand conversion whereas more aggressive silvicultural techniques that include scarification

would better emulate the soil disturbing processes that naturally control paludification.


Table 1. Factors that impact ecological resilience at various spatial scales in boreal

forest ecosystems

scale Process Structure Other

environmental

factors

anthropogenic

impacts

Stand seed dispersal,

natural

regeneration,

competition,

pollination,

herbivory, disease,

photosynthesis,

respiration, evapo-

transpiration,

nutrient cycling,

allelopathy,

mycorrhizal

association

vertical,

horizontal, stand

density, relative

species mixes,

patch size &

shape

soil moisture,

pH, light

availability,

temperature,

nutrient

availability,

slope-aspect,

altitude, latitude,

Timber harvest,

soil erosion,

compaction,

land conversion,

invasive species,

climate change,

conversion,

structural and

compositional

simplification,

pollution

Landscape Natural

disturbance,

succession,

nutrient cycling,

hydrological

cycling,

paludification

Variation in

forest types &

age class, stand

pattern &

connectivity

Soil moisture,

nutrient

availability,

physiography

Fragmentation,

homogenization,

sedimentation &

waterflow

alteration,

climate change,

pollution

Region Primary

production climate

regulation

Variation in

forest types &

age class, patch

pattern &

connectivity

temperature,

precipitation,

CO2, ozone, N

deposition &

uptake,

physiography

Fragmentation,

homogenization,

sedimentation &

waterflow

alteration,

climate change,

pollution

Understanding the dominant processes and their interactions is clearly an important step

to effective management. Such an understanding will be critical when dealing with novel

combinations of disturbances such as the interaction of allelopathy, clearcutting, and fire that

have resulted in some conifer forest ecosystems to be converted to heathlands (Mallik 1995,

Payette and Delwaide 2003), invasive insect pests that can substantially alter forest structure

and composition (Dukes et al 2009), and use of other inappropriate harvesting analogues

(Nitschke 2005, Salonius 2007, Taylor et al. 2013).

Unprecedented changes to the historical frequency or severity of natural disturbances is

also problematic. Fire regimes that are more frequent than the age of sexual maturity of tree

species, for example, can lead to ecosystem change. Increased frequency of stand-replacing

fires has resulted in conversion of aspen woodland to conifer forest (Strand et al. 2009) and

conifer forests to grasslands (Heinselman 1981, Hogg and Hurdle 1995, Beckage and

Ellingwood 2008). Noble and Slatyer (1980) used knowledge of these processes and tree


functional attributes to identify when and why species shifts would occur as disturbance

processes changed. In fact, ecological research throughout history has been about identifying

shifts in ecosystem states due to changes in natural disturbances as well as those caused by

humans (Frelich and Reich 1998). Clements (1928) was concerned about how the agricultural

practices of his time influenced the integrity of mid-plains ecosystems. Holling (1978)

identified the importance of disturbance in maintaining resilience; exemplified by the spruce

budworm (Choristoneura fumiferana) maintaining balsam fir forests in the Maritimes by

killing the canopy and releasing understory trees whereas fire, which is a rare disturbance in

this ecosystem, can lead to a different forest type. Thus, processes that can cause ecosystem

collapse usually do not have historical precedents and are often the result of anthropogenic

changes to the timing or severity of natural processes. Accordingly, human disturbances

should be evaluated in light of the processes they affect and the subsequent impacts on

species present across the landscape.

2.3. At What Spatio-temporal Scales Should We Focus Our Management

Efforts?

Ecological resilience changes over time and space. Thus, understanding the critical

processes driving a system must include knowledge of the spatio-temporal scales over which

they operate and interact (e.g., Heinselman 1981, Gunderson and Holling 2002, Mladenov et

al. 2008). Different ecological processes influence community structure and composition at

different spatial and temporal scales (Ricklefs 1987, Herzog and Kessler 2006, Seppä et al.

2009) (Figure 2). Certain processes can also have impacts across scales of measure. These

processes often do not function in a simple linear fashion, nor do they function independently

of one another (Peterson et al. 1998, Frelich and Reich 1999, Groffman et al. 2006).

Extrapolating ecosystem responses to these processes by scaling up or down may result in

erroneous assumptions and predictions due to non-linear relationships, differences in

environmental characteristics at different scales, and emergent properties (Peterson 2000,

Turner et al. 2001). Therefore, we need to understand if and how critical processes impact our

forests at stand, management unit, and regional levels.

Effective management requires careful planning of how each desired objective is

distributed across the forest management unit. Thus, the scope should be large enough to

generate region-wide ecological benefits that compensate for impacts of an objective at a

single site as well as the cumulative impacts of multiple interventions of this and various

other objectives over time. For example, while the effects of logging are site specific, we need

to consider the spatio-temporal impacts on the forest management unit as a whole; not just

accommodate short-term and local needs or demands. If an associated objective is to maintain

structural complexity across the landscape, including large tracts of mature forest to provide

core habitat for wildlife and various aesthetic values, then a mixture of large and small cuts

arranged in an aggregated pattern across the management unit could allow for more intact,

interior forest conditions to be retained across the landscape relative to a strategy creating

smaller, uniform patches distributed systematically. Over time, a more fragmented landscape

with a greater edge-to-interior ratio may develop utilising the systematic approach (Turner et

al. 2001).


Figure 2. Some important processes affecting boreal forest ecosystems across spatio-temporal scales.

2.4. How Do We Determine If a System Is Resilient or Not?

At this time, ecological resilience can only be coarsely quantified using a proxy; i.e.,

measured in terms of the amount of biodiversity, structural heterogeneity, response diversity,

and ecological redundancy. Biodiversity and structural heterogeneity are defined as the

amount of variation in biological (genes, species, and ecosystems) and structural elements

(vertical strata of extant vegetation, spatial arrangement of patches, snags, coarse woody

debris, pit & mound topography, etc.), respectively (Hunter 1999). Response diversity is the

variation in responses of functionally similar species to disturbance (Elmqvist et al. 2003); for

example, black spruce (Picea mariana) regenerates almost exclusively from the abundant

seed rain after severe fire while white birch (Betula papyrifera) and poplars (Populus spp.)

can reproduce via seed, but can also regenerate vegetatively. Ecological redundancy is the

extent to which a forest ecosystem structure, process, or function is substitutable if a

degradation or loss in the main species that provides that particular attribute occurs (Folke et

al. 2004). A system having greater quantities of a proxy is thought to be more resilient

(Loreau et al. 2003, Fischer et al. 2006). Response diversity and ecological redundancy are

deemed particularly important as multiple species performing the same critical function can

replace or compensate for substantial losses in a dominant species, as well as display

variation in responses to disturbance or gradual change (Thompson et al 2009).


An abundance of research shows that the chances of shifting into another stability domain

increase when removal, reduction, or drastic changes to any of these proxies occurs (e.g.,

Naeem et al. 1995, Loreau et al. 2003, Contamin and Ellison 2009). Larger impacts on critical

ecosystem processes are typically observed when there are fewer species present, when the

dominant or keystone species are strongly affected, or when functional redundancy is low

(Pastor et al. 1996, Lavorel et al. 2007, Rinawati et al. 2013). Thus, greater species diversity

may confer greater ecological resilience (Hooper et al. 2005, Fischer et al. 2006). Yet this

may not always be the case (e.g., Petchey and Gaston 2009). Some boreal systems with

relatively low species diversity levels are also resilient. For example, black spruce (Picea

mariana) and balsam fir (Abies balsamea) forest ecosystems both have low functional

diversity and redundancy, yet are both highly resilient to catastrophic fire and insect

disturbance, respectively (Pollock and Payette 2010, Boiffin and Munson 2013).

Black spruce and balsam fir trees are well adapted to these severe disturbances and have

a broad genetic diversity that can tolerate a wide range of habitat conditions (Thompson et al.

2009). Thus, while high levels of diversity may not be expressed at the species or community

levels of organization, at the genetic level, these species have the necessary components for

renewal and reorganization. However, questions remain as to how these ecosystems will

respond to climate change. Balsam fir, for example, regenerates poorly after fire (Asselin et

al. 2001) while jack pine (Pinus banksiana) regenerates poorly in its absence (Parisien et al.

2004). Boiffin and Munson (2013) observed shifts in species dominance from black spruce to

jack pine after a period of unusually high fire activity that caused changes in microhabitat

suitability for germination. Large scale changes to species distribution patterns will likely

occur across the landscape if these periods of large fire years become more frequent. Other

concomitant effects of climate change are also of concern. Changes to habitat suitability for a

number of spruce beetle species (Dendroctonus spp.) along the west coast of North America

have expanded the potential for their impacts in both altitude and latitude (Bentz et al. 2010)

for example.

So how much diversity is enough to maintain resilience? Clearly there is still much to be

resolved with this aspect of ecological resilience. It is difficult to ascertain the quantity of a

proxy required for stability or which proxy is most important for any particular forest

management unit given that differences in local physiographic attributes, disturbance regimes,

and the spatial or temporal scale of measurement can change expected contributions (Loreau

et al. 2002, Lavorel et al. 2007). Further, knowledge of the functional roles of many species

remains incomplete (Grime 1998, Scherer-Lorenzen et al. 2005), and thus it can be difficult to

judge the adequacy of response diversity or ecological redundancy.

Management is facilitated by clear objectives and by concrete numbers that support and

validate them; and ecological resilience theory, at this stage of its conceptual development

cannot provide them. In the ball and cup model of Figure 1, this equates to determining

exactly how close to a threshold edge an ecosystem’s current state is, how quickly it can

tumble towards it, and how much a proxy can keep it from drawing nearer or can drive it

away from collapse. Modeling that projects changes in critical processes into the future is

only beginning (e.g., Hirota et al. 2011, Gustafson 2013, Lafond et al. 2013) so detecting or

predicting critical changes such as shifts between stable ecosystem states is still problematic.

Thus, it remains an enormous task to shift knowledge of the adequacy of ecological resilience

from hindsight to a useful predictive tool as we still don’t know where thresholds are until

after they are crossed.


But do we really need to know exactly where thresholds lie or just the impacts of the

processes that lead to them? Shouldn’t we be able to identify signals of tumbling towards

shifts in forest ecosystem states, and use these signals as qualitative indicators of the risks of

surpassing undesirable threshold points? As it is, we are not even able to effectively identify

key species or their response functions (e.g., whole plant, stem and below ground, or

regeneration traits) (Grime 1998, Scherer-Lorenzen et al. 2005, Lavorel et al. 2007). Thus, the

precautionary principle; n.b., Leopold’s (1949) argument that the intelligent rule to tinkering

is not to get rid of any of the pieces, suggests that all species should be maintained. Moreover,

a recent synthesis (Cardinale et al. 2012) suggests that increased diversity also begets

increased ecosystem productivity, which implies that a call for maintaining biodiversity does

not need to be based on altruism or ethical considerations but may be for our own best

interest.

Perhaps another issue is that we’re expecting that managing for ecological resilience (or

any other management option) should account for everything a priori. Questions arise such

as: is management that promotes maintaining processes such as disturbance regimes within

natural historical ranges of variation even useful if the resultant patterns and relationships are

expected to change or decouple altogether with global change? How do we know if oncoming

novel disturbance types and/or disturbance interactions will be beyond what our forest

management unit can absorb? These are questions that perhaps no amount of management or

management approach can truly account for a priori. This may also require us to accept that

domain shifts will occur as conditions exceed the adaptations of local species. For example, if

conditions become too xeric for moisture sensitive species such as balsam fir. The ability to

adapt human institutions that depend on natural ecosystems will thus be tantamount to socio-

ecological resilience as the ecosystems themselves re-organize.

3. PUTTING IT ALL TOGETHER: THE WAY FORWARD

Ecological resilience may eventually be an important management option. But at its

current conceptual iteration, there are too many details that require development or resolution

prior to it being used as a general operational tool. In particular, the lack of knowledge of a

number of critical processes and how they function and interact across spatio-temporal scales,

the uncertainty associated with relationships between resilience and the quantity of

biodiversity needed to maintain stability, as well as the lack of quantitative approaches to

determine an ecosystem’s position in state space relative to threshold points need addressing.

Despite this, there are several elements of ecological resilience that are already being used in

contemporary forest management. Many of the requirements to maintain ecological resilience

are the same factors central to other forest management paradigms. For example,

contemporary forest management approaches guided by knowledge of ecosystem processes

and functioning such as Ecosystem Management, Emulating Natural Disturbance, and

Managing for Complexity are consistent with ecological resilience principles (Holling 1978,

Grumbine 1994, Perera et al. 2007, Gauthier et al. 2008).


Figure 3. Conceptual diagram of the balance of social, economic, and environmental objectives under

Forest Ecosystem Management linked across scales. We cannot manage for everything everywhere. In

our example here, the ball represents an objective. In (a) an economic objective takes precedence but

overall effects are beyond the adaptive capacity of the ecosystem at the microsite scale but since there

are many sites within a stand if we manage at the stand scale then the impacts at some sites will be

balanced out by others for stand level resilience (b) effects can be balanced by applying conservation on

some sites and more intensive forestry somewhere else across the landscape; (c) shows multiple

objectives across the region, each having a specific focus, but impacts on other objectives are always

considered. Ecosystem function is maintained by processes that can interact and affect the ecosystem at

one or a number of scales. Elimination of an objective occurs when disturbance or slow change drives

species responsible for providing objective beyond the ‘tipping point’ (i.e., threshold limit of resilience)

at the regional scale (indicated by the dashed arrow). Restoration is now required to re-introduce source

or basis of objective. Ecosystem collapse can occur when detrimental impacts of an objective are

beyond the adaptive capacity of the groups of species responsible for regulation of key ecosystem

processes driving the system. Link between scales is dependent on the connectivity and pattern of forest

patches across scales and the processes controlling them.

An approach based on Ecosystem Management (Grumbine 1994), one that integrates

various aspects of other contemporary paradigms at multiple scales of focus will help

minimize risk of changing stability domains as well as maintain processes and attributes

identified when asking ‘from what to what’. Managing forest resources so that processes

remain within historic natural ranges of variability are stressed, but stakeholders should be

flexible enough to adapt strategies as more information becomes available. As in the TRIAD

approach to forestry management (Seymour and Hunter 1992), the forest management unit

could be partitioned into zones where either social, economic, or conservation objectives are

emphasized, the proportion of which are pre-determined by stakeholder agreement, and this

pattern repeated across the landscape at various spatio-temporal scales (Figure 3). At each


scale of focus, an adaptive strategy is used. This is an iterative approach wherein the effects

of management policy and stakeholder actions are periodically evaluated and modified as

necessary; essentially, as outcomes from natural events and management actions become

better understood (Holling 1978). Thus, it is a multidisciplinary, dynamic, and multi-scalar

approach to Ecosystem Management based on processes responsible for natural historic

ranges of variation. It emphasizes frequent communication, research, and information

exchange among stakeholders. The use and modification of procedures derived from

continuously updated knowledge of ecosystem dynamics is the underlying premise for

stakeholder exchanges.

Consistent with the requirements for building ecological resilience, this strategy

recognizes the importance of a range of variability in natural processes in contributing to

forest ecosystem functioning. The strength of the approach would be in the ability to identify

changes in conditions created by anthropogenic disturbances from multiple viewpoints and at

multiple scales. Moreover, complexity and variation of forest ecosystems are emphasized

rather than avoided while modeling and forecasting could incorporate spatial structure and

processes, in addition to traditional modeling parameters (Baskent and Yolasiǧmaz 2000). So

rather than focusing on attaining a single optimal ecosystem condition, a range of acceptable

outcomes is managed for, and thus, potentially reducing vulnerability to unforeseen

disturbance and gradual change across the entire forest management unit; n.b., similar to the

ball and cup metaphor, this is analogous to having a number of balls moving around in the

desired ecosystem state space at the same time (Figure 3).

CONCLUSION

Operationalising ecological resilience is an admirable goal. But at this stage of its

conceptual development, its use in management planning is limited. Instead it is perhaps best

used as a monitoring tool to evaluate the success of other strategies (e.g., TRIAD, Ecosystem

Management, Emulating Natural Disturbances). Until our understanding of critical processes

and ability to predict shifts in ecological states improves, current management approaches

that draw attention to the processes driving ecosystem dynamics across spatio-temporal

scales, as well as linking these processes with societal uses and values should be emphasized.

ACKNOWLEDGEMENTS

Lively discussions and feedback from a number of individuals, including H. Archibald,

H. Chen, B. Freedman, T. Gooding, B. Harvey, K. Hylander, T. Jain, M. Kennedy, H.

Kimmins, N. Klenk, D. Kreutzweiser, L. Leal, C. Messier, A. Miller, A. Mosseler, A. Park,

K. Peterson, K. Puettmann, M. Willison, L. Van Damme, S. Woodley, and R. Tittler were

important in helping to develop ideas and clarify concepts presented here.


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