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206
At a stand level and as a generalization, the dynamics of moist tropical and subtropical
rainforests following disturbance can be explained by a few interrelated factors (Swaine and
Whitmore 1988; Hopkins 1990; Finnegan 1996; Richards 1996; Terborgh et al. 2002; Wright
2002). First, mature rainforest has a closed canopy and a shady understory. Second, the long-
lived trees that dominate mature rainforest are relatively shade tolerant and slow growing,
and their seeds typically germinate on dispersal. Third, rainforests also support a suite of
shade-intolerant, fast-growing plants (“pioneers”) whose seeds persist in the soil and whose
germination is stimulated by the increase in heat and light that accompanies disturbance to
the canopy. Fourth, animals are key agents in the pollination, dispersal, and consumption of
rainforest plants.
Consequently, in rainforests with an intact fauna, moderate-scale disturbance of the can-
opy (large tree-fall gaps to blowdowns of several hectares) typically gives rise to the following
successional sequence: Pioneers recruit from the seed bank, grow rapidly to form a closed
canopy, but do not recruit under their own shade. As the pioneers senesce, they are replaced
by slower-growing, shade-tolerant, long-lived trees either present as seedlings at the time of
disturbance or subsequently dispersed to the regenerating forest from surrounding areas of
rainforest (fig. 14.1). We note that this successional model considerably simplifies variation in
plant traits and ecological strategies and does not address issues concerning the maintenance
of diversity in rainforests (Tilman 1994; Westoby et al. 2002; Wright 2002). Nevertheless, this
model has been widely used to describe the ecology of rainforests and often forms the basis
of strategies developed for their exploitation (Hartshorn 1989; Hopkins 1990; Kooyman 1996;
Richards 1996; Lugo 1997; Duncan and Chapman 2003; Ganade 2007; Holl 2007).
In this chapter, we consider the utility of successional and alternate models (e.g., King
and Hobbs 2006; Cramer 2007) for describing forest dynamics and informing the conduct of
restoration projects in rainforest landscapes subject to broadscale anthropogenic disturbance.
Such landscapes are characterized by extensive areas of cleared land dominated by grasses,
crops and other exotic vegetation, patches of remnant forest, areas of secondary forest on mar-
ginal agricultural land, and various types of tree plantations (Richards 1996). Our examples
are drawn largely from Australian rainforests, the focus of our research experience. We begin
with a brief description of intact Australian rainforests before discussing disturbed systems.
Chapter 14
Dynamics and Restoration of Australian Tropical
and Subtropical Rainforests
John Kanowski, Robert M. Kooyman, and Carla P. Catterall
206
Hobbs-Suding Ch_14-Ch_17.indd 206 11/3/08 8:59:35 AM
Environmental Determinants and Dynamics of Australian Rainforests
Until the mid-Tertiary, rainforests covered much of Australia. Currently, they cover around
3 million ha, or 0.4% of the continent, mostly in higher-rainfall areas along the east coast
(Cofinas and Creighton 2001). Despite their limited extent, rainforests remain important
repositories of biodiversity, supporting, for example, 60% of Australian vascular plant fami-
lies and 17% of Australian bird species, including many endemic taxa (Lynch and Neldner
2000). From a global perspective, Australian rainforests have some unique characteristics,
including the presence of a number of “primitive” angiosperm families (Adam 1992) and a
distinctive fauna, such as marsupial frugivores and folivores rather than primates (Primack
and Corlett 2005).
At a landscape scale, the composition and structure of Australian rainforests vary primarily
with temperature, soil nutrient availability, and rainfall (Webb 1968; Floyd 1990; Kooyman
and Rossetto 2006). Distinct forest types, defined in terms of structural attributes or their char-
acteristic floristic composition, are associated with particular combinations of these environ-
mental factors (Webb et al. 1976; Tracey 1982). For example, “complex notophyll vine forests”
occur on relatively fertile soils subject to moderate to high rainfall and a “mesotherm” climate
14. Dynamics and Restoration of Australian Tropical and Subtropical Rainforests 207
FIGURE 14.1. Model of the dynamics of intact rainforests on fertile soils in tropical and subtropical
Australia following disturbance, with sequential stages of recovery dominated by (1) shade-intolerant,
fast-growing, short-lived “pioneer” species; (2) longer-lived pioneer trees; and (3) shade-tolerant, slower-
growing, long-lived “mature-phase” trees. Stages 1 and 2 are transient, and stage 3 may be persistent.
Hobbs-Suding Ch_14-Ch_17.indd 207 11/3/08 8:59:37 AM
208 dynamics and restoration of different ecosystem types
(i.e., lowlands in the subtropics, uplands in the tropics), whereas “simple notophyll vine for-
ests” occur on poorer soils in otherwise similar environments (Webb 1968; Nix 1991).
In the field, transitions between forest types can occur over short distances in conjunction
with abrupt changes in environmental conditions. For example, rainforest types can change
from “complex” to “simple” from one side of a watercourse to the other, with a change in
underlying soil parent materials (Tracey 1982). Similarly, there is often a sharp transition
between rainforest and fire-tolerant eucalypt forest, mediated by topographical features that
act as a barrier to the spread of fire (Ash 1988).
At a stand level, the dynamics of Australian rainforests vary in response to the intensity
and frequency of disturbance events (Hopkins 1990) and also with forest type. In “complex”
rainforests on fertile soils, these dynamics tend to follow the successional model presented in
figure 14.1, at least for disturbances that open the forest canopy sufficiently to stimulate the
regeneration of pioneer species from the soil seed bank (Floyd 1990; Hopkins 1990; Kooy-
man 1991; Kariuki and Kooyman 2005). In contrast, the species that regenerate after distur-
bance in “simple” rainforests on poorer soils include many long-lived trees that also occur in
mature forest (Floyd 1990; Kooyman 1999).
Dynamics of Australian Rainforests in Anthropogenically
Disturbed Landscapes
Australian Aborigines have utilized rainforests for many thousands of years (Horsfall and Hall
1990). Through their use of fire, Aborigines modified the distribution of rainforest, and their
hunting- and-gathering practices presumably influenced the distribution and abundance of
harvested species (Newell 1999; Bowman 2000; Hill et al. 2000). Nevertheless, the tradi-
tional livelihood of the Aborigines relied on the persistence of rainforest and its resources.
European settlers converted extensive areas of rainforest to agricultural land, mainly sugar-
cane plantations in the lowlands and pasture and horticultural crops in the foothills and
uplands (Erskine et al. 2007). Clearing was restricted mostly to forests on fertile soils, and many
cleared areas remain under agricultural production. However, in the subtropics, large areas
of marginal agricultural land have been abandoned in the past few decades and now support
secondary forest (Neilan et al. 2006). There are also around 50,000 ha of monoculture timber
plantations and 5,000 ha of mixed-species plantings established on former rainforest land in
the Australian tropics and subtropics (Catterall and Harrison 2006; Erskine et al. 2007).
In the following paragraphs, we discuss the dynamics of these remnant forests, second-
ary forests, and replanted areas (fig. 14.2). Given the long time scales involved in rainforest
dynamics and restoration and the paucity of relevant longitudinal studies, we are not in a
position to evaluate which type of model “best” describes these systems. Instead, we consider
how successional and alternative models draw attention to different aspects of forest dynam-
ics and how these approaches can inform restoration practices.
Rainforest Remnants
Small patches of rainforest have persisted in extensively cleared landscapes in Australia for 50
to 100 years. For example, there are 30 remnants >1 ha of the former “Big Scrub,” a 75,000-ha
Hobbs-Suding Ch_14-Ch_17.indd 208 11/3/08 8:59:37 AM
14. Dynamics and Restoration of Australian Tropical and Subtropical Rainforests 209
lowland subtropical rainforest that was cleared between 1860 and 1900 (Adam 1992). Many
remnant rainforests have been subjected to disturbance from logging, cattle grazing, fire, and
invasion by exotic plants, while all are exposed to an altered physical environment (increased
light, wind and temperature variation), particularly on their edges (Lamb et al. 1997; Laur-
ance 1997). Furthermore, it seems likely that the floristic composition of remnants will be
impacted by changes in the distribution and abundance of fauna involved in plant regenera-
tion, particularly seed dispersers, seed predators, and herbivores (Wright and Duber 2001;
Cordeiro and Howe 2003). For instance, rainforest–dependent frugivorous birds responsible
for dispersing the large, fleshy fruits of mature-phase rainforest trees have declined in some
subtropical remnants (Moran et al. 2004).
Successional models figure prominently in the approaches developed by practitioners to
restore Australian rainforests (Goosem and Tucker 1995; Kooyman 1996; Big Scrub Rainforest
(a) (b)
(c) (d)
FIGURE 14.2. (a) Remnant rainforest, tropical Australia. (b) Mixed-species rainforest plantation,
subtropical Australia. (c) Secondary forest in subtropical Australia dominated by the exotic tree,
camphor laurel (Cinnamomum camphora). (d) Regenerating rainforest, eight years after the camphor
laurel overstory was poisoned.
Hobbs-Suding Ch_14-Ch_17.indd 209 11/3/08 8:59:40 AM
210 dynamics and restoration of different ecosystem types
Landcare Group 2005). For example, when applied to remnant rainforests, the model presented
in figure 14.1 predicts that the long-term dynamics of remnants may be adversely impacted by
dispersal limitation. Consequently, the restoration of “corridors” to facilitate dispersal between
remnant forests has underpinned much of the revegetation effort conducted in Australian
rainforest landscapes over the past few decades (Lamb et al. 1997; Tucker 2000).
However, successional models do not readily predict some aspects of the degradation
of remnant forests. For example, in many subtropical remnants, disturbance of the canopy
has resulted in the vigorous growth of exotic vines that smother trees and further disrupt
the canopy. These conditions also favor the growth of exotic herbaceous ground covers that
can suppress the regeneration of rainforest plants (Floyd 1990; Kooyman 1996; Harden et
al. 2004). In such cases, it may be useful to consider alternative models to describe the
processes involved in degradation and identify restoration strategies. For example, a “biotic
and abiotic threshold” model (Whisenant 2002; King and Hobbs 2006) could be applied to
the degradation of remnants driven by the positive feedback among canopy disturbance, the
growth of exotic vines, and the spread of herbaceous ground covers. In rainforest, the canopy
is considered a key regulator of abiotic conditions, with a closed canopy suppressing light-
demanding vines and ground covers (Floyd 1990; Kooyman 1996). Restoration practices that
have prioritized the reestablishment of a closed canopy and hence the abiotic conditions
characteristic of intact rainforest have proven successful in restoring remnants degraded by
exotic vines (Harden et al. 2004; Big Scrub Rainforest Landcare Group 2005). Earlier resto-
ration practices that focused primarily on the control of the herbaceous ground covers were
unable to halt the decline of these remnants.
Secondary Forests
Intensive agricultural pursuits in rainforest landscapes have frequently been abandoned
because of declining productivity or changes in economic conditions (Richards 1996; Ers-
kine et al. 2007; Ganade 2007). The redevelopment of rainforest following the abandonment
of agriculture may be constrained by the destruction of the rainforest seed and seedling
banks, the limited dispersal of seeds from remnant forests, predation on dispersed seeds, a
reduction in soil fertility, competition from exotic plants, and repeated disturbance from fire
and grazing (Hopkins and Graham 1984; Uhl et al. 1988; Hau 1997; Lamb et al. 1997; Holl
1999; Toh et al. 1999; Holl et al. 2000; Erskine et al. 2007). Under these circumstances,
abandoned agricultural land may remain covered by exotic grasses and shrubs.
Nevertheless, if abandoned agricultural land is protected from fire and other major distur-
bances, secondary forest will often eventually replace the grassland (Richards 1996; Corlett
2002). The transition to secondary forest can occur rapidly if land is abandoned shortly after
clearing and subsequently protected from disturbance, in which case rainforest plants may
regenerate from residual rootstocks and the seed bank, supplemented by dispersal if forests
are nearby (Uhl et al. 1988; Richards 1996; Erskine et al. 2007). In other cases, the transition
may take decades (Toh et al. 1999; Holl 2007). In disturbed landscapes, the initial coloniz-
ers of abandoned land are often exotic plants; consequently, secondary forests dominated by
exotic plants now cover large areas of former rainforest land (Ewel and Putz 2004; Zimmer-
man et al. 2007). In the Australian subtropics, for example, secondary forests dominated by
Hobbs-Suding Ch_14-Ch_17.indd 210 11/3/08 8:59:40 AM
14. Dynamics and Restoration of Australian Tropical and Subtropical Rainforests 211
the exotic tree camphor laurel (Cinnamomum camphora) have recolonized around 25% of
cleared land in the former “Big Scrub” (Neilan et al. 2006).
The concepts of facilitation and inhibition, inherent in classical successional models, are
useful in understanding some of the dynamics of secondary forests (Hopkins 1990; Finnegan
1996; Richards 1996; Ganade 2007; Holl 2007). The presence of trees and shrubs in former
agricultural land can facilitate the recruitment of rainforest plants because they attract seed-
dispersing animals and suppress grasses that might compete with recruits (Lamb et al. 1997;
Toh et al. 1999; Aide et al. 2000; Ganade 2007). Conversely, trees and shrubs also tend to
inhibit the growth of recruits through mechanisms such as allelopathy, root competition, and
shading (Bazzaz 1979; Tilman 1994; Ganade 2007; Loh and Daehler 2007).
Exotic tree colonizers in abandoned farmland are a particularly interesting case of the ten-
sion that exists between the contrasting roles of facilitation and inhibition, with implications
for restoration strategies. When exotics are relatively short lived and shade intolerant, as is the
case for Spathodea campanulata, the dominant colonizer of abandoned land in Puerto Rico,
then passive restoration (doing nothing in the expectation that the recruitment of native spe-
cies will be facilitated by the colonizing trees) may be an effective strategy (Zimmerman et
al. 2007). However, when the exotics are long lived, shade tolerant, or capable of altering key
environmental conditions such as soil nutrient status (as is the case for the leguminous tree
Myrica faya in Hawaii; Loh and Daehler 2007), passive restoration is more risky.
In Australia, debate over the management of regrowth dominated by camphor laurel reflects
different perceptions of its role in promoting (or retarding) the development of rainforest on
abandoned land. Some ecologists have argued for the widespread control of camphor laurel
(Floyd 1990), while others have argued for its retention, at least as an interim measure (Neilan
et al. 2006). Camphor laurel clearly facilitates the recruitment of rainforest plants to grass-
land: It establishes among and shades out pasture grasses; when mature, it bears a heavy crop
of fleshy fruits that attracts frugivorous birds and bats that disperse the seeds of rainforest plants
and exotics to camphor stands (Neilan et al. 2006). However, camphor laurel can potentially
live for centuries, during which time it may suppress recruits (Scanlon and the Camphor Lau-
rel Task Force 2000). Given the uncertainty about the long-term trajectory of camphor stands,
restoration practitioners have developed selective or patch-scale culling treatments to acceler-
ate the growth of rainforest plants in camphor stands (Woodford 2000; Lymburner et al. 2006;
fig. 14.2d).
Identifying the factors that drive or inhibit transitions among grassland, secondary forest,
and mature rainforest is an important element in the development of restoration strategies
for disturbed rainforest landscapes (Holl 2002). The model presented in figure 14.1 identi-
fies dispersal limitation as a key factor potentially truncating the development of secondary
forest. The large seeds of mature-phase rainforest trees that are often dispersed by rainfor-
est–dependent fauna are rarely dispersed to secondary forests isolated from remnant forest
(Corlett 2002; Cordeiro and Howe 2003; Moran et al. 2004; Erskine et al. 2007; Holl 2007).
However, secondary forest may not progress toward the condition of intact rainforest for other
reasons, including dominance of the seed rain by exotic plants (Holl 2007), elevated rates of
seed predation or herbivory (Hau 1997; Holl et al. 2000), changes in underlying soil and/or
hydrological conditions from past land uses (Zimmerman et al. 2007), and repeated distur-
bance (Richards 1996).
Hobbs-Suding Ch_14-Ch_17.indd 211 11/3/08 8:59:40 AM
212 dynamics and restoration of different ecosystem types
Alternative conceptual models of the dynamics of secondary forests, such as state-and-
transition models (King and Hobbs 2006), can help draw attention to the range of factors
driving transitions between different types of vegetation cover in disturbed rainforest land-
scapes (fig. 14.3). For example, the dispersal of plants from the disturbed matrix can strongly
influence the composition of secondary forests, which are usually dominated by small-seeded
pioneers and exotic plants (Duncan and Chapman 2002; Neilan et al. 2006).
Replanted Sites
Extensive areas of rainforest have been converted to plantations of timber trees (Lugo 1997).
In Australia, plantations in rainforest landscapes are predominantly monocultures of the
native conifer Araucaria cunninghamii, with smaller areas of mixed-species timber planta-
tions and restoration plantings (Kanowski et al. 2003; Catterall et al. 2004). Restoration plant-
ings typically use a diverse range of species planted at high densities to rapidly attain canopy
closure and suppress weeds (Kooyman 1991, 1996; Lamb et al. 1997).
Successional concepts have played an important role in the development of replanting
strategies. For example, both timber plantations (when used as part of a restoration strategy)
and restoration plantings are intended to facilitate the recruitment of rainforest plants to
formerly cleared land (Lamb et al. 1997). Restoration plantings are explicitly based on suc-
cessional models in terms of their composition (usually a mix of pioneers and mature-phase
species) and variation in composition with proximity to remnant forests. Planting designs
developed for sites adjacent to remnant forests are comprised mainly of pioneers on the
assumption that mature-phase species will readily disperse and recruit to such sites. In con-
trast, designs developed for more isolated sites include a substantial component of mature-
phase species, particularly large-seeded and wind-dispersed trees with limited potential for
long-distance dispersal (Goosem and Tucker 1995; Kooyman 1996; Freebody 2007).
Nevertheless, it may be useful to consider revegetation strategies within a state-and-transi-
tion framework (fig. 14.3) because successional models do not necessarily address the range of
factors that may influence the long-term dynamics of replanted sites. For example, experience
has shown that pioneer-dominated restoration plantings often do not recruit an understory
of mature-phase rainforest plants as intended, even when located adjacent to remnant for-
ests. Instead, the understory of these plantings often becomes dominated by light-demanding
weeds, either present in the seed bank or dispersed from the surrounding matrix, that then
suppress the recruitment of rainforest trees (Kooyman 1996; Freebody 2007). Similarly, con-
sideration of landscape-scale factors influencing the dynamics of reforested sites may lead to
greater skepticism of claims that plantations can facilitate rainforest regeneration in broadscale
restoration programs (Parrotta et al. 1997; Lamb 1998; Lamb et al. 2005). Many tree species
grown commercially in plantations (e.g., conifers, eucalypts) do not bear fleshy fruits and
hence, when isolated from remnant forests, are unlikely to attract the specialist frugivores that
disperse the seeds of mature-phase rainforest plants (Tucker et al. 2004; Kanowski et al. 2005).
Consequently, although plantations adjacent to remnant forests may recruit a diverse range of
rainforest plants (Chapman and Chapman 1996; Keenan et al. 1997; Lamb et al. 2005), more
isolated plantations are likely to be dominated by small-seeded pioneers and exotic plants dis-
persed from the surrounding matrix (Corlett 2002; Duncan and Chapman 2002).
Hobbs-Suding Ch_14-Ch_17.indd 212 11/3/08 8:59:40 AM
14. Dynamics and Restoration of Australian Tropical and Subtropical Rainforests 213
Conclusions
Techniques for restoring rainforests to cleared land have been informed by successional
models developed from observations of intact rainforests (Floyd 1990; Hopkins 1990; Kooy-
man 1996). These techniques have been successful insofar as restored sites can develop a
rainforest–like structure and provide habitat for some rainforest–dependent biota within
one to two decades of establishment (Kanowski et al. 2003, 2006; Grimbacher et al. 2007;
Kanowski and Catterall 2007; Catterall et al. 2008). However, few restoration projects have
been established long enough to progress to the stage where planted trees have been replaced
by species dispersed to the restored site let alone converge on target conditions. As succes-
sional models address only some of the factors influencing the dynamics of restored sites in
disturbed landscapes, it may be useful to consider alternate models of forest dynamics to
inform the long-term management of restored sites (table 14.1).
A state-and-transition model of the dynamics of restored sites (fig. 14.3) suggests that these
sites will often require long-term intervention, including the control of exotic plants and the
addition of native species, to converge on the condition of intact forest. Because the costs of
FIGURE 14.3. Model of the dynamics of secondary forests and replanted rainforests in anthropogenically
disturbed Australian rainforest landscapes. Rectangular boxes = potentially stable states (persisting for
more than one generation of dominant species); parallelograms = transitional states.
Hobbs-Suding Ch_14-Ch_17.indd 213 11/3/08 8:59:42 AM
214 dynamics and restoration of different ecosystem types
Table 14.1.
Models of ecosystem dynamics applicable to forested lands within Australian tropical
and subtropical rainforest landscapes.
Forest Type Successional Models Alternative Models Application to Restoration
Intact rainforest
(extensive areas of rainforest with
intact faunal assemblages)
The recovery of forests on fertile soils
after disturbance is often described by
successional models (fig. 14.1).
None (at the stand scale). Restoration interventions in intact
rainforest are rare, as recovery
through autogenic processes is
usually assumed. Some heavily
logged sites have been treated (e.g.,
by replanting and vine control) to
hasten succession (Kooyman 1999).
Remnant rainforest
(small patches of rainforest in
otherwise disturbed landscapes)
Successional models identify dis-
persal limitation as a factor
influencing the dynamics of
remnant forests.
The degradation of remnants
following disturbance of the canopy
and invasion by exotic vines could be
described by a “biotic and abiotic”
threshold model, with the canopy
regulating abiotic conditions.
A common landscape-scale target
of restoration is the establishment
of corridors to improve dispersal
between remnants. The primary site-
scale target of remnant restoration
is reestablishment of the canopy, if
disturbed.
Secondary forest
(regrowth forests developed after
clearing, often dominated by
exotic plants)
The concepts of facilitation
and inhibition are useful for
understanding the dynamics of
secondary forests: Established trees
may facilitate plant recruitment by
attracting dispersers and suppressing
grasses but may also inhibit the
growth of recruits.
“State-and-transition” models can
provide a useful framework for
describing the long-term dynamics
of secondary forests, as they focus
on site- and landscape-scale drivers
of the trajectory and stability of
secondary forests and alternate types
of vegetation cover.
Secondary forests can recover
considerable structure and function
by autogenic processes but may
require intervention (e.g., control
of exotics, enrichment planting) to
converge on the condition of intact
rainforest, depending on the longevity
and shade tolerance of colonizing
species and the recruitment of
rainforest plants.
Hobbs-Suding Ch_14-Ch_17.indd 214 11/3/08 8:59:42 AM
14. Dynamics and Restoration of Australian Tropical and Subtropical Rainforests 215
Table 14.1.
Models of ecosystem dynamics applicable to forested lands within Australian tropical
and subtropical rainforest landscapes, continued.
Forest Type Successional Models Alternative Models Application to Restoration
Replanted sites
(monoculture and mixed-
species timber plantations, diverse
restoration plantings)
Replanting strategies and techniques
draw heavily on successional
models. “Pioneer” plantings and
timber plantations (when used for
restoration) are explicitly intended to
facilitate the recruitment of mature-
phase rainforest plants.
The long-term dynamics of replanted
sites are likely to be contingent on the
same site- and landscape-scale factors
that influence remnant forests and
secondary forests. These dynamics
may be usefully described by state-
and-transition models.
Techniques for establishing rainforest
trees in Australian tropical and
subtropical landscapes are well
developed. Planting strategies
generally assume that sites will
converge on intact rainforest through
autogenic processes, but long-term
intervention may be necessary to
control weed invasion and to enrich
species composition in cases where
dispersal is limited. To be effective,
intervention needs to be coupled with
a systematic monitoring program.
Hobbs-Suding Ch_14-Ch_17.indd 215 11/3/08 8:59:43 AM
216 dynamics and restoration of different ecosystem types
intervention can be high, particularly if a problem such as weed invasion is not controlled at
an early stage, the routine monitoring of restoration projects may need to become a neces-
sary part of their management (Catterall et al. 2008). At present, most Australian rainforest
restoration projects are not monitored in any formal way (Kanowski et al. 2008; although for
counterexamples, see Kooyman 1996; Tucker and Murphy 1997; Harden et al. 2004).
Once the long-term outcomes of restoration projects are better known (e.g., through more
systematic monitoring), there may need to be a reassessment of what constitutes appropriate
“target conditions” for restored sites. It may become apparent, for example, that most restora-
tion projects are so small and isolated and so heavily influenced by the disturbed matrix that
the structure, composition, and dynamics of restored sites will always tend to diverge from the
condition of intact rainforest. If so, it may be necessary to accept stable assemblages of native
and exotic plants (“emerging” or “new forests”; Ewel and Putz 2004) as the target for most
restoration projects. Alternatively, investment in projects aimed at reestablishing assemblages
typical of intact rainforests may need to be restricted to high-value applications (e.g., habitat
for threatened species or plantings strategically positioned to act as future seed sources; Kooy-
man 1996) rather than being used as the default approach across the landscape, as currently
tends to be the case.
All models of rainforest dynamics recognize the importance of landscape context in
affecting the trajectory of restored sites. To date, much restoration effort in Australian has
been expended on the creation of corridors to facilitate dispersal between remnants. How-
ever, corridors do not address other landscape-scale factors affecting the persistence of biota
in remnants, such as the influence of the surrounding matrix. A better understanding of the
relative importance of the extent and configuration of rainforest cover at the landscape scale
(e.g., Bennett et al. 2006) and integration of this knowledge into models of rainforest dynam-
ics is required to inform future restoration projects aimed at conserving rainforest biota.
Acknowledgments
Thanks to Peter Erskine, Kylie Freebody, Cath Moran, Miriam Paul, Scott Piper, and Tang
Yong for participating in a workshop on “Rainforest Dynamics and Restoration,” where the
ideas presented here were developed. The contributions of JK and CC to this article were
supported in part by funding from the Australian government’s Marine and Tropical Sciences
Research Facility.
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