Resilience
Resilience
The capacity of the environment to retain or recover essentially the same structure and functions when it experiences shocks or disturbances.
Overview for Resilience
Resilience is the ability of the environment to withstand or recover from a shock or disturbance. Although the concept of resilience was developed and is mainly used in relation to ecosystems, it is a valuable concept across the environment and in environmental management. Effective environmental management aims to maximise the health or adaptability of the environment to improve its resilience to current, ongoing and future pressures. In SoE 2016, each thematic report discusses what resilience means for that theme.
Resilience concepts can potentially help us to recognise that, although some level of change is inevitable and normal, change that is too frequent or too rapid can lead to abrupt changes in the environment that may be very difficult or impossible to reverse.
The terms ‘tipping points’ and ‘boundaries’ are often used in relation to abrupt and irreversible changes. A tipping point can be regarded as an ecological threshold beyond which major change becomes inevitable. A boundary is a human-determined value that sets the distance from a tipping point that a society is prepared to maintain (see Rockström et al. 2009).
In general terms, Australia’s natural and cultural systems can be considered resilient in terms of resisting and recovering from shocks and disturbance, including the natural variability and change of the environment for which Australia is well known. For example, Australia’s biodiversity is renowned for its ability to deal with very significant variability (fire, extended periods of dry or wet, extreme weather events such as cyclones). During the past few decades, we have learnt more about the multitude of strategies that different species employ to provide resilience to change.
However, the extent to which Australia’s natural and cultural systems will continue to demonstrate resilience in the face of trends and shocks remains to be seen. Although Australia’s biodiversity is well adapted to past change, including a certain frequency of extreme climate events, it may not be well adapted to future rates of environmental change. The reduced quality and connectivity of the habitat of many species may further diminish their resilience to such change.
Evidence shows that some tipping points have already been passed in Australia. For example, researchers in southern Western Australia have documented change in the structure and composition of Australian temperate reef communities, which, in the past 5 years, have lost their defining kelp forests and become dominated by persistent seaweed turfs (Wernberg et al. 2016).
Healthy ecosystems are better able to replace lost organisms with the next generation, and areas of high biodiversity are more likely to contain species that can withstand a particular disturbance. Bleached coral reefs have recently fully recovered in remote areas that are free from other human pressures (Gilmour et al. 2013), but the same cannot be said for reefs exposed to heavy human use.
The cumulative impact of multiple pressures may also affect the resilience of the environment. A system may be resilient in the face of one or a few pressures, but this may break down as pressures of different types and magnitudes accumulate, or as tipping points are passed. Management actions, such as environmental watering, reduction of invasive species and management of competition, may only have a significant beneficial impact on resilience if they are undertaken at a sufficient scale and with appropriate timing to address the pressures. The eradication of cats, rabbits, rats and mice from Macquarie Island is an example of actions that were sufficient to completely remove invasive species and allow ecosystem recovery.
Science and investments by governments, combined with the efforts of landowners, communities and environment organisations working on-ground, are identifying opportunities for managing the Australian environment in ways that retain or rebuild the resilience needed to cope with future pressures. Examples include the following:
- The National Landcare Programme supports actions by communities working in conjunction with land managers and policy-makers to restore habitat and ecosystems, increase the conservation estate, identify and protect refuges, and restore connectivity to degraded landscapes.
- The Murray–Darling Basin Plan is helping to manage resilience in one of our most significant inland water resource basins by ensuring that water resources are not overallocated or overused, thereby providing a buffer for changing conditions.
- The large and expanding Indigenous Protected Areas estate builds capacity within Indigenous communities to manage land and sea Country in ways that benefit both the wellbeing of their community and biodiversity.
Structured scenarios and active adaptive management are 2 useful tools for building resilience that are sometimes used by planners, communities and decision-makers (Folke et al. 2002).
Scenario exercises that produce projections or if–then case studies (e.g. if we follow scenario A, then the expected outcome for the future is B) can help to assess potential impacts of change on socio-ecological systems (Evans et al. 2015), and to identify policies and management actions that might attain or avoid particular future outcomes (Folke et al. 2002).
Adaptive management is informed by on-ground observations of the effectiveness of actions. Adaptive management is suited to building or maintaining resilience because it acknowledges that all systems are subject to variability and change, is flexible, encourages learning through evaluation, and promotes the capacity to innovate in light of evolving understanding and circumstances (see Folke et al. 2002).
At a glance
The frequency, duration and severity of episodes of poor air quality in urban centres are influenced by short-term meteorological conditions, in combination with local topography and/or atypical emissions. Air quality is usually restored to acceptable levels once the immediate conditions change, either through a change in the wind, cessation of the emissions, rain or dispersion of the pollutant. Therefore, our urban airsheds may be considered highly resilient, in terms of the common dictionary definition of the word. However, human resilience to the effects of prolonged or recurring exposure to air pollutants is limited.
At a glance
For the built environment, resilience refers to the capacity of the built environment to retain or recover its structure, functions and amenity after experiencing shocks.
Historically, Australian cities have coped reasonably well with disaster events such as storms or floods, and disaster management is a key component of urban planning. However, the increased frequency of such events associated with climate change may require additional planning and coordination. Tools such as the Critical Infrastructure Resilience Strategy and the Enhancing Disaster Resilience in the Built Environment roadmap are helping to build this capacity. Climate change will also require additional planning to ensure that the built environment remains resilient in such areas as water supply and quality.
However, our built environments are less resilient to our increasingly urbanised growth and longer-term climate impacts, such as sea level rise. Planning for long-term growth, change and adaptability will be needed to deliver ongoing resilience of our built environments.
At a glance
Our planet is somewhat resilient to increasing carbon dioxide (CO2) levels because atmospheric CO2 is absorbed by the oceans. During recent decades, the oceans have taken up approximately 25 per cent of the annual anthropogenic CO2 emissions to the atmosphere. However, the capacity of the oceans to absorb CO2 appears to be limited, because the absorbed CO2 is making our oceans more acidic, with consequent environmental impacts.
The lag in the system is significant. Modelled projections show that, if CO2 levels are ramped down to pre-industrial concentrations, surface air temperature and sea level change exhibit a substantial timelag relative to atmospheric CO2—in models, even 900 years after CO2 was restored to pre-industrial levels, surface air temperature and sea level were considerably higher than under pre-industrial conditions.
The palaeorecord confirms this modelling. In the Palaeocene–Eocene Thermal Maximum era (56 million years ago), CO2 was being released to the atmosphere at one-tenth of the rate of today. The era resulted in a rapid onset of 6 °C global warming, followed by a gradual recovery during 150,000 years. Although many species ultimately survived, the perturbations to the environment of this warming persisted for tens of thousands of years.
The interaction between the environment and society means that resilience of the physical environment and human societies must be considered together.
Resilience of a society to climate change is dependent on the sensitivity of the society to change and its capacity to adapt to change. Climate-resilient pathways may involve significant transformations in political, economic and socio-technical systems. The success of climate-resilient pathways is linked to the success of climate change mitigation (i.e. as problems become unmanageable, future options for climate-resilient pathways may be reduced).
Climate change will result in location-specific vulnerabilities, and people who are disadvantaged are most sensitive to climate change. However, some regions may benefit from climate change (e.g. warmer temperatures will result in reduced energy demand for winter heating and reduced winter mortality in cooler climates, including southern Australia).
Within Australia, Indigenous communities may be particularly vulnerable to climate change impacts, particularly those people who live in remote interior or low-lying coastal areas, or who rely on natural resources for their livelihoods. However, adaptation and mitigation to climate change may offer opportunities for Indigenous communities through engagement with environmental management.
It is important that vulnerabilities in social resilience are reflected in national and international policies aimed at adapting to climate change.
At a glance
The resilience of Australia’s heritage can be considered in relation to both individual heritage places and the total heritage resource.
The ability of individual places or wider resources to withstand shocks depends on the nature of specific heritage values and their susceptibility to change. The resilience of the overall heritage resource is a function of what is protected through the reserved lands system or individual heritage lists and registers.
The current resilience of Australia’s heritage cannot be readily assessed based on available information. However, there are opportunities to improve the resilience of Australia’s heritage through better data gathering, regular maintenance, specific risk preparedness and disaster planning.
At a glance
Resilience is a key underpinning principle of Australia’s Biodiversity Conservation Strategy 2010–2030, as well as state and territory, and regional biodiversity strategies. The definition of resilience in biodiversity strategies and policies is still relatively ambiguous, and needs to be more clearly quantified and articulated to measure the success of these strategies. Ecological resilience is generally defined as the ability of ecosystems to resist permanent structural change and maintain ecosystem functions.
Australia’s biodiversity is well adapted to variable climate conditions and to a certain frequency of extreme events. However, the current rate and magnitude of change in climate, compounded by other pressures, are beginning to seriously challenge the natural adaptive capacity of our biodiversity. There are many initiatives and activities being undertaken across Australia, from local to national scales, that will improve the resilience of our biodiversity to future pressures. However, there is growing evidence that some vulnerable ecosystems are undergoing permanent structural change because of extreme climate impacts, signalling a clear loss of resilience in these systems. Further work is required to understand thresholds before tipping points are reached beyond which irreversible changes to ecosystems occur.
At a glance
Australian landscapes have evolved with soils and vegetation in equilibrium with the climate and natural disturbance regime. Land management activities disturb that equilibrium. Although we may not see all of the ensuing changes, the subtle and slowly accumulating ones can be the most significant in terms of altering the future supply of resources and services from the land.
Resilient land should be able to recover from changes, and continue to support native vegetation and natural processes, as well as allow us to use natural resources within reasonable limits. A challenge for Australians is to decide how much to demand of the ancient and complex Australian land environments without destroying them.
Native species and ecological communities have evolved to cope with, and sometimes heal, the effects of natural disturbance events. If too much native vegetation is cleared and too much of the soil microbiota is lost, the chances of recovery are compromised. Australian land managers are improving their understanding of how to retain resilience, although in some cases this requires active rehabilitation of landscapes or ecological communities. Improved collaborative approaches to managing the whole of the Australian environment are needed to retain or rebuild the resilience that will be needed to cope with future pressures.
At a glance
A challenge in assessing resilience of inland water environments is recognising resilience when it occurs, especially because Australian ecosystems have developed to be both resistant and resilient.
We can contribute to resilience by reducing extreme and detrimental ecosystem disturbances, and increasing the ecosystem characteristics needed to increase resilience. Management of streamflow releases, provision of environmental flows, and management to reduce impacts on groundwater levels and quality can all contribute to resilience. The success of these can be assessed after an ecosystem shock—when it is possible to assess whether detrimental changes that we have seen previously or that we expected to occur—were found either to have not occurred or to have been less severe.
Early outcomes of the Commonwealth Environmental Water Office’s Long-Term Intervention Monitoring Project in the Murray–Darling Basin include positive resilience outcomes in improved vegetation condition, recruitment of waterbirds and fish, improved aquatic habitats, support for ecological recovery, natural thinning of seedlings, and improved survival and condition of individuals.
A future opportunity for assessment of resilience in inland water environments lies in the assessment of cumulative impacts of negative or positive factors, especially regarding ecosystem thresholds and tipping points.
At a glance
Resilience of the coastal environment includes its resistance to change and its ability to recover once disturbed. Resistance to change is linked to the maintenance of high biodiversity, which is expected to provide greater redundancy in ecological functions. Resistance can also be increased by improving the tolerance of important keystone or habitat-forming species to pressures. Furthermore, resistance to additional pressures can be improved by minimising the impacts of other pressures.
Recovery from change can be facilitated through active restoration or by limiting human use to allow natural recovery. Defining appropriate baselines and quantifying the success of recovery are key challenges for restoration ecology. Protection from some degree of human use is the most common method of ecosystem recovery in coastal Australia, and the extent of protected coastal environments in Australia has increased during 2010–14. There have also been several recent efforts in active restoration, where human intervention aims to restore an ecosystem to a predefined state.
Resilience is defined as the capacity for a system to experience shocks while retaining essentially the same function, structure and feedbacks, and therefore identity. This report considers 2 components of coastal resilience: the extent to which the coast can resist change in the face of pressures, and how well it can recover from change once disturbed.
At a glance
Resilience can be considered to be the capacity of a system to keep functioning even when disturbed. Current understanding of the resilience of Australia’s marine environment is limited because of the vast spatial extent of Australia’s marine ecosystems, their complexity, the many and varied sources of pressures exerted on them, and the limited capacity to monitor them across relevant timescales. Recent research has shown that reduction of pressures in marine reserves can increase the resilience of reserve species to remaining pressures, such as freshwater incursions associated with flooding or establishment of range-shifting species. The contribution of individual reserves or reserve networks to the resilience of the larger marine ecosystem, however, remains to be determined.
Two useful tools for building resilience in socio-ecological systems are structured scenarios and active adaptive management. In marine ecosystems, structured scenario frameworks are being used to investigate the impacts of commercial industries and climate change, and to test management strategies that might be implemented in response. Adaptive management frameworks, which monitor and assess biological and economic conditions, and adjust management strategies as required, are being implemented for commercial fisheries across Australian Government, and state and territory jurisdictions. Australia now provides regional and international leadership on adaptive fisheries management frameworks.
For most sectors, however, existing management plans for the marine environment are reactive rather than proactive, and are not coordinated across sectors. As a result, many plans fail to address the cumulative nature of multiple impacts and do not support the development of resilience within marine ecosystems. Adaptive governance and adaptive management may be needed to address the cross-sectoral and cross-jurisdictional contributions to cumulative impacts. The expanding National Representative System of Marine Protected Areas provides an opportunity to determine how removal of local pressures contributes to long-term resilience within, and external to, the protected area or network. This will require sustained ecological monitoring for at least the next decade.
At a glance
Although organisms living in Antarctica have evolved to cope with severe events, it is challenging to measure their level of resilience and to predict how future climate change will affect Antarctic ecosystems. This is largely because our understanding of key parameters is still limited, and with it our ability to assess adaptability and, hence, resilience of organisms and ecosystems.
