managed adaptive capacity of coastal wetland complexes. Very high – within sea level inundation zone Very high – high exposure Poor – in sea level inundation zone, marine/ estuarine transformation Poor – low gradient coasts, sea level rise fast, development landward
Pressures Invasive species Grazing Altered fire regimes Water resource development Catchment development Catchment Climate change Sea level rise Exposed to source of pressure (Yes/No) Yes; Great Barrier Reef catchment wide. Pressure temporal dimension varies from long chronic strain to periodic stress. Usually greater pressure from weeds in more developed basins and due to feral animals in less developed basins. Yes; Great Barrier Reef catchment wide with localised exclusions from urban, agricultural, protected and rainforest areas. Exposure to pressure depends on land management practices and wetland landscape context. Yes; Great Barrier Reef catchment wide but variable exposure. Lower in higher rainfall Wet Tropics, and more intensively developed urban and agricultural, areas. Exposure to pressure depends upon land management practices and interacts with other pressures including invasive grass species and grazing. Yes; Localised. Higher pressure in developed river basins from Cairns south, particularly those that support irrigated agriculture and/or major population centres and for wetlands downstream of major infrastructure. Pressure associated with both infrastructure and flow impacts. Yes; Great Barrier Reef catchment wide. Greater pressure is associated with areas of both existing and proposed more intensive development, (i.e. within river basins from Daintree south and predominantly on the near coastal lowlands within these basins). Pressure is associated with land use intensity, and pattern and both direct site impacts on freshwater wetlands (including instream infrastructure) and indirect impacts via disturbance on catchment biophysical processes and contribution to contaminant loads in catchment run- off. Yes; Great Barrier Reef catchment wide. Pressure temporal dimension varies from long chronic strain to periodic stress. Pressure closely related to catchment development pattern, land use practices and entrained land degradation processes. Catchment run-off pressure is comprised of both contaminant loads and altered run-off hydrology. Yes; Great Barrier Reef catchment wide. Long temporal scale chronic pressure. Yes; Localised to near coastal lowlands. Potential for regional and basin wide significant impacts as a result to changes to dependent ecological processes and species.
pyrophytic grasses and or exclusion of grazing (including protected areas adjoining regularly burnt pastoral areas) more intensively developed seasonally dry urban and agricultural areas extend suppression / too infrequent burning, which results in realised wildfire risks sugarcane growing areas use burnt cane harvesting resulting in remnant wetlands exposure to regular unintentionally burning or where wetlands are intentionally infrastructure and flow regime changes (including both reduced flows or additional / aseasonal flows) and extraction levels move system across thresholds that generate major changes in wetland function and condition or wetland occurs upstream of major water infrastructure that represents a complete connectivity barrier and wetland community species composition and basin population levels has been altered. Very high Where wetland is the site for water resource infrastructure development e.g. riverine, lacustrine wetland Where wetlands occur: in basins /catchments dominated by more intensive agricultural or urban / industrial development with overall land use pattern predominantly monotypic intensive use with remnant vegetation areas occurring as isolated patches, drainage lines as narrow discontinuous and/or degraded riparian vegetation corridors and off stream wetlands retained as isolated remnants often lacking riparian vegetation within intensively developed contributing catchment areas in areas with currently intensive) land use (e.g. rangeland grazing on unimproved native pastures) but extreme weather events droughts/floods significantly impact catchment condition in basins that past or current land management practices have not ensured for the retention of adequate ground cover during rainfall periods, and there has also been significant development of land degradation (particularly alluvial gully and waterway bank erosion) In areas where cumulative impact of catchment condition changes and/or irrigated farm / significant populations of biota with dependent linkages to it. Very high Where wetland occurs within the sea level rise inundation zone. Will ultimately experience complete transformation to highly modified / novel estuarine – marine system.
burnt as part of farm fire risk management 13 developed to dam, weir, holding storage. medium exposure but are being subject to land use intensification or wetlands occur in moderately developed basins but built infrastructure that generates direct site impacts on wetlands (e.g. bund walls, dams, road crossings) is extensive. point source discharges results in some hydrological changes in receiving aquatic ecosystems. High – very high Where wetlands occur in basins : with a predominantly extensive land use pattern but there has been significant current or historical development of land degradation (particularly alluvial gully and waterway bank erosion) and some impairment of regulatory ecosystems services controlling contaminant load retention/ transport. with a variegated pattern of land use but land use practices result in significant off
vegetation but has been subject to other pressures (invasive species, development, grazing) that have resulted in structural and floristic changes that have introduced fire into the wetland and make it prone to ongoing burning. regime affected by water infrastructure development or extraction e.g. peak overbank flood flows reduced by dams, are key drivers of wetland functions (e.g. connectivity) and habitat condition (e.g. channel scouring). where impacts result in short or extended term stress but not long-term chronic strain, generating altered but still functional wetlands. Secondary pressures (weeds, water quality decline) can establish during stressful periods which are often mitigated by climatic conditions, with stress occurring during more extreme weather and being reduced by habitat resetting events (e.g. flushing flood events, extended base flows) under better weather conditions. High – Very High: Where exposure to development pressure is high and wetland has been impacted by hydrology, resulting in the establishment of some secondary pressures (weeds, water quality decline and condition and function impacts associated with short or extended term stress but not long-term chronic strain, generating altered but still functional wetlands. Sensitivity to such stressful periods are often mitigated by climatic conditions, with stress occurring during more extreme weather and being reduced by habitat resetting events (e.g. flushing flood events, extended base flows) under better weather conditions. Extreme weather events droughts/floods limited other pressures (e.g. catchment invasive species, water resource development) operating. Moderate sensitivity will be experienced by wetlands that fall within the range of conditions described for low (above) or High (below) sensitivity. This will include wetlands in higher, evenly distributed rainfall regions but with greater levels of other operating pressures that can be exacerbated by climate change or alternatively wetlands in more seasonal climatic regions but with less or few other pressures operating that can be exacerbated by climate change.
open, brackish versus permanent fresh, scoured versus sandy versus muddy substrate. hydrology, establishment of multiple secondary pressures (weeds, water quality decline) Sensitivity to such stressful periods is often mitigated by climatic conditions, impacts exacerbated during more extreme weather and being reduced by habitat resetting events (e.g. flushing flood events, extended base flows) under better weather conditions. Extreme weather events droughts/floods that significantly impact catchment condition can also result in high sensitivity in catchments where exposure to pressure is otherwise medium. and extreme climate events increasing due to climate change (e.g. poor/degraded catchment condition, eutrophication, chronic weed infestations, water resource development / altered flow regimes, hot fire regimes, high sediment and other contaminant loads and flow or reach condition based connectivity impacts).
for each of these community types to recover. longer term system stain emerging in relation to secondary pressures (e.g. weed infestation, water quality decline, structural and composition changes). Good where water resource infrastructure connectivity impacts are avoided or fully mitigated (e.g. off stream storage, biota bypass channels) and/or flow / extraction impacts are below thresholds that drive ecosystem change including via targeting components of natural flow regime that allow for maintenance of key flow or connectivity associated ecological processes and functions (e.g. baseflows, will also be poor. Where wetlands occur on the edge of wet tropical or upland biogeographic / climatic boundaries and climate change pushes these sites into drier, hotter climatic settings with different flow regimes e.g. wet tropics to seasonal dry tropics the adaptive capacity of the existing communities particularly to novel; pressures such as fire and flow cessation will be poor. Moderate natural adaption capacity to climate change will be associated with: wetlands that have not had their resilience undermined by other site or catchment cyclones and storm surges. Good where wetlands occur outside of the sea level rise inundation zone or in the longer term on inland boundary of the ultimate sea level rise inundation zone once sea level rise reduces to median historical rates or stabilises.
overbank flood flow habitat resetting) and the establishment of secondary pressures (e.g. weed infestation, water quality decline, structural and composition changes) have been avoided. condition pressures. wetlands that occur in areas that naturally have moderate levels of climatic variability in which biota have preadapted to seasonal stresses that will be enhanced under climate change. This capacity will be enhanced where flow regimes are partially supplied by groundwater contributions (that maintain flows and/or refugia) those associated with deeper aquifers (not as readily impacted by seasonal rainfall changes). wetlands that occur in large hydrologically connected catchments that extend across climatic zones and contain a
range of associated flow regimes wetlands with community members that have broader flow, water quality, temperature and fire regime tolerances. Adaptive (Poor, moderate, good) Moderate to Good. Moderate where significant investment of resources and catchment based management is required where invasive species dominate systems on a large spatial scale, represent long-term chronic infestations or occur in remote areas with limited human resources. However management models developed within the Reef catchment in Moderate to Good. Moderate where: social /economic constraints limit opportunities to reduce high total grazing pressure medium to high grazing pressure has been sustained for long periods landscape context or type of wetland have made it susceptible to pressure and/or structure and function of wetland has been modified to Poor to Good. Varies in relation to wetland community fire sensitivity, wetland condition and land use context. Poor where levels of wetland disturbance from other pressures (invasive grasses, climate change) create permanent changes in fuel load dynamics, and associated wild fire risks and have undermined natural recuperative capacity, and/or wetlands occur Moderate to Good. Moderate where the following apply: large scale older water infrastructure involved and/or wetlands are used as part of supply infrastructure high levels of flow allocation are committed to consumptive uses key flow and connectivity associated processes and Moderate to Good. Moderate where the following apply: Where wetland exposure and/or sensitivity to development pressures has been high intensive land use in contributing catchments and abutting and into wetland boundaries is extensive catchment development Poor to good. Through integrated coastal management decision making, policies and legislation there is potential to explicitly recognise the intrinsic value of freshwater wetland habitat and implement protection. Significant actions are already underway to halt and reverse the decline in water quality entering the Great Barrier Reef including implementation of Poor to Moderate. The extent and persistence of impacts from climate change will depend on the success of international efforts to curb the rate of accumulation of greenhouse gases in the atmosphere, and on the resilience of the ecosystem to the changes in climate that manifest over coming decades. Given current trajectories of greenhouse gas emissions, Poor to Moderate The capacity to adaptively manage Reef catchment freshwater wetland assets in the face of pressures presented by sea level rise is not tried or tested. While this is an important area for research and development most suggested approaches remain largely theoretical and draw on experience gained on the creation and maintenance
there are dedicated human resources with a capacity to deliver ecological fire regime outcomes (some protected areas, Traditional Owner lands). dividend. Good Where the following apply: water infrastructure is off stream or if on stream is not large scale and has connectivity impacts mitigated by biopassage statutory Water Resource Planning has ensured flow allocations to meet the needs of flow dependent ecological assets including (via the retention of flow regime elements that drive important ecological functions) the condition of system has been managed to avoid establishment of secondary constraints in such intensively developed catchments. Good Where the following apply: wetland exposure and/or sensitivity to development pressures has been low to moderate catchment land use patterns are variegated retaining a mix of intensive and extensive land uses with remnant vegetation catchment development levels have not undermined the integrity of all biophysical process and the associated capacity for ecosystem service provision. status has generated permanent changes in catchment hydrology (e.g. hard panning, laser levelling) where land tenure is predominantly freehold development density presents limited spatial opportunities for reinstatement of buffer and detention functions. In less intensively developed basins widespread land degradation e.g. subsoil exposure/ gully erosion can also contribute to poor adaptive management capacity. Other constraints include where: secondary (4) Protecting and restoring functionally important catchment ecosystem elements such as riparian zones and other catchment vegetation cover to increase receiving freshwater ecosystem resilience (5) Moving beyond current environmental flows to restoration of flow regimes (including flow manipulation in highly regulated systems) that efficiently focus on key ecosystems and processes, protected areas and significant sites (6) Reducing anthropogenic impacts on aquatic refugia, gain an improved understanding of their spatial and temporal extents of coastal interface wetland complexes the site is remote and available human resources are limited. Moderate capacity will occur where: rates of sea level rise are freshwater wetlands occur on higher gradient, relatively elevated sloping coastal lowlands site occurs in wet tropics where sustained freshwater discharge or aquifer levels maintain a hydraulic head against sea water intrusion there are low levels of
pressures. Good adaptive management is also supported where natural adaptation capacity has been retained and few secondary pressures have established. Adaptive management in this development context needs to address pressures associated with both existing and potential future development. This requires a mix of asset protection for high integrity wetlands and important functional processes, threat management to address and prevent secondary pressures (weeds, bank stability etc.) and system restoration for where existing development pressures (e.g. weeds) have become entrenched natural adaptive management capacity has been lost cultural practice and economic pressures are an impediment to adoption of Best Management Practices on farm where the climate is highly seasonal and tending toward more frequent extreme events. Moderate where exposure and sensitivity to pressure is medium and catchment land use, condition, functional process integrity and natural adaptive management capacity lies between that and increase their recognition in policy frameworks (7) Improving governance and adaptive management including use of catchment management frameworks, legislation that supports the resilience of rivers and wetlands, integration of aquatic ecosystem conservation management responsibilities at a catchment scale and adaptive management based on (1) set management objectives, (2) identified action thresholds and (3) monitoring. Considering these management approaches: Poor adaptive management capacity will hydraulic connectivity with estuarine/ marine areas areas landward of coastal wetlands are undeveloped providing opportunities for inland migration of coastal interface wetland complexes the site is served with sufficient human and other resources to deliver more intensive management options including bunding / barraging of high value assets, creation of managed brackish mixing zones, assisted landward migration / creation of freshwater wetland habitats within the coastal plain.
pressure has impaired functions (hydrology, connectivity). Through integrated state and local government development decision making, policies and legislation there is potential to explicitly recognise the intrinsic value of wetland habitat and implement protection during new development. Developments are subject to assessment, licensing and conditions that can protect freshwater wetlands. Codes of practice and water sensitive urban design are in place to manage stormwater in local areas. described for poor (above) and good (below). Good where exposure and sensitivity to pressure is low and existing impacts to wetland condition and function have emerged as a result of short term or spatially limited stress rather than strain. Adaptive management capacity is best where contributing catchment areas have limited intensive development associated with high contaminant loads and natural catchment buffers remain or are capable of being repaired/ reinstated and catchment run-off hydrology behaves similar to baseline generally be associated with wetlands that retain only poor natural adaption capacity (described above), particularly where they occur in remote areas with entrenched land use pressures and limited human or other resources to address other operating pressures. Moderate adaptive management capacity will be associated with wetlands that retain moderate natural adaption capacity (described above) particularly where they occur in relatively undeveloped high integrity basins with higher rainfall and climatic regions less exposed to seasonal
Erosion and sediment control plans are legislated requirements during construction phases of development. Penalties apply for non-compliance. Cumulative impacts are however difficult to assess. conditions in terms of flow duration curves and land degradation is limited. Management capacity is also enhanced by an absence of entrenched secondary pressures (e.g. weeds) where: natural adaptive management capacity remains there are economic and/or legislative incentives to support adoption of Best Management Practices on farm and where the climate is less seasonal and extreme events infrequent. extremes. In more developed basins, a moderate adaptive management capacity could be achieved through higher levels of investment in addressing other existing pressures on catchment and wetland condition including through dedicated flow regime management in more highly regulated basins predicated on the recognition that a functional albeit modified freshwater wetland provides an ecosystem service dividend.
is not a short-term problem with a simple solution. It will take many years to improve practices that generate contaminant loads throughout Reef catchments and also to allow for the targeted repair and reinstatement of catchment ecosystems services that regulate their transport and retention. Level of confidence in supporting evidence (Poor, moderate, good) Good. Good Good. Good. Knowledge of relationship between water resource development thresholds and Moderate. Cumulative impacts are difficult to assess. Knowledge of catchment Moderate. Knowledge of end of catchment loads good but transport pathways uncertain. Poor. High uncertainty surrounds predictions for the magnitude or rate of climate change impacts that will Poor High uncertainty surrounds predictions on the rate and ultimate extent of sea level rise and of the
key flow driven processes requires further development. development threshold relationships to biophysical process integrity and ecosystem service delivery requires further research. Knowledge of thresholds of tolerance to pollutants, as well as light limitations is poor. A degree of uncertainty surrounds effectiveness of strategies to minimise run-off from agricultural lands. be experienced by Reef catchment wetlands. natural or managed adaptive capacity of coastal wetland complexes to sea level rise. © Commonwealth of Australia 2016 Published by the Great Barrier Reef Marine Park Authority ISBN 978-1-922126-90-0 (pdf) This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without the prior written permission of the Great Barrier Reef Marine Park Authority.