Category Archives: Wetland

Regeneration of indigenous vegetation at Third Reedy Lake as it has dried over summer and autumn 2022

Posted on 24 June 2022 by | Comments Off on Regeneration of indigenous vegetation at Third Reedy Lake as it has dried over summer and autumn 2022

Damien Cook

Introduction.  Third Reedy Lake is a freshwater wetland in the Kerang region in north central Victoria. It is part of the Kerang Wetlands Ramsar Site, which means that it is recognised as being of international significance for wetland conservation as it supports threatened plant and animal species and ecological communities and rookeries of colonial nesting wetland birds.

Prior to European occupation this wetland, along with Middle Lake and Reedy Lake, would have been inundated only when floodwaters came down the Loddon River and caused the intermittent Wandella and Sheep Wash Creeks to flow. At that time the wetland experienced a natural wetting and drying cycle, filling up from floodwaters and drying out completely between floods, which occurred on average once every 3 to 4 years.

In the 1920s, however, this natural wetting and drying cycle was discontinued. Third Reedy Lake became part of the Torrumbarry Irrigation Scheme. Water was diverted out of the Murray River at Torrumbarry Weir and made to flow through a series of natural wetlands including Kow Swamp, the Reedy Lakes, Little Lake Charm and Kangaroo Lake to deliver water to irrigate farms. The lakes and swamps became permanently inundated.  While this meant farmers had a reliable supply of water it also profoundly altered the ecology of the wetlands (Fi. 1).

Figure 1. Third Reedy Lake in February 2013 prior to being bypassed. Continuous inundation for around a century had drowned the native vegetation, leaving only skeletons of trees. (Photo D. Cook)

Trees such as River Red Gum (Eucalyptus camaldulensis) and Black Box (E. largiflorens) were drowned, lake bed plants that relied on a drying cycle could no longer grow and the ecological productivity of the wetlands was massively reduced. The density of wetland birds has been found to be positively correlated to wetland productivity and this metric has been used in a variety of ecological studies to compare the use of different habitats by wetland birds. During bird counts conducted in 2018 the highest density of birds on Third Reedy Lake was about 5 birds/hectare. In contrast the naturally intermittent Lake Bael Bael supported over 60 birds/hectare, a density 12 times higher. While Third Reedy Lake supported a maximum of 17 wetland bird species Lake Bael Bael supported a maximum 38 wetland bird species.

Works undertaken

Hydrological works.  Third Reedy Lake was deemed to be inefficient for moving water due to losses caused by evaporation and so it was intentionally bypassed by the irrigation scheme in 2020. The lake therefore dried for the first time in one hundred years over the summer of 2022. Environmental water will be periodically delivered to the wetland in the future to mimic its natural wetting and drying cycle and assist ecological recovery.

Revegetation works. Over 2000 River Red Gum trees and 1000  understorey plants, including Tangled Lignum (Duma florulenta) and Southern Cane-grass (Eragrostis infecunda), have been planted across the centre of the lake where no natural regeneration was likely to occur in the short to medium term. Members of the local Barapa Barapa and Wemba Wemba Traditional owner communities were employed to plant the trees and other plants (Fig. 2). The Barapa Barapa and Wemba Wemba Traditional Owners have a strong interest in the wetland because of its cultural values.


Figure 2. Uncle Trevor Kirby with a Red Gum he has just planted and guarded at Third Reedy Lake April 2022. . Virtually no native vegetation remained visible on the lake bed immediately after the long inundation. (Photo T. McDonald)

The River Red Gum seedlings have been planted next to dead River Red Gum stumps to replicate the original woodland structure of the wetland (Fig  3). Planting next to the stumps has other advantages; they provide shelter from the wind and sun and soil carbon and moisture levels are highest close to the rotting wood.

Figure 3. River Red Gum seedling planted next to an old red gum stump, Third Reedy Lake May 2022. (Photo D. Cook)

Results to date.  In the first 3 months without inundation the lakebed muds dried out, followed by deep cracking (Fig 2). Planted trees thrived as there was still ample moisture in the sub-soil.  Site inspections in May 2022 revealed that substantial natural regeneration of the wetland has begun (Fig. 4).

After 100 years without drying it was not known if any seed bank of the original lakebed vegetation would have survived. However, 46 native species have been recorded growing on the lakebed since the last of the water evaporated from the lake in April 2022. This includes two threatened species: Floodplain Groundsel (Senecio campylocarpus) and Applebush (Pterocaulon sphacelatum) (Fig. 5) . The germination of Applebush is particularly surprising given that this is only the fourth record of this plant in Victoria, the species being more common in the arid centre of Australia. Other indigenous species that have regenerated on the lakebed are shown in Figs 6 and 7.

Figure 4. Lake bed herbs regenerating after the drying phase, at Third Reedy Lake, May 2022 . A total of 46 native species have been recorded as having regenerated on the lakebed since the last of the water evaporated from the lake in April 2020 (Photo D. Cook)

Figure 5. Among the 46 native species regenerating is Applebush (Pterocaulon sphacelatum) which is particularly surprising as it is listed as endangered in Victoria and known to occur in only three other locations. (Photo Dylan Osler)

Figure 6. Spreading Nut-heads (Sphaeromorphaea littoralis), Third Reedy Lake May 2022. This species is uncommon in the Kerang region, the closest records to Third Reedy Lake being from the Avoca Marshes. (Photo D. Cook)

Figure 7. Golden Everlasting (Xerochrysum bracteatum) and Bluerod (Stemodia florulenta) make an attractive display of wildflowers. These species are uncommon at present but if weeds are controlled adequately, they should recolonise much of the wetland floor. (Photo D. Cook)

River Red Gum regeneration has been localised on the bed of the lake and has mainly occurred on the fringes close to where living Red Gum trees have shed seed. The densest Red Gum regeneration has occurred on a sandy rise close to the inlet of the lake, where the trees have grown rapidly (Figs 8 and 9). Many of the seedlings that have germinated on the edge of the lakebed are being heavily grazed by rabbits or wallabies.

Figure 8. Regenerating Red Gums and native grasses and sedges on a sandy rise near the inlet of Third Reedy Lake, May 2022.(Photo D. Cook)

Figure 9. River Red Gum seedling on cracking clay soil that has germinated near the lake edge. Many of these seedlings are being heavily grazed, probably by rabbits or wallabies. (Photo D. Cook)

The young trees will take many years to develop the hollows required by many species of wildlife, but hopefully the old stumps will persist for some time to provide this important habitat feature (Fig 10). When these trees grow large enough, they will provide shady nesting sites for colonial nesting wetland birds such as Australasian Darter (Anhinga novaehollandiae) (Fig. 10) and Great Cormorant  (Phalacrocorax carbo) and replace the dead standing trees as they rot and fall over.

Figure 10. Australasian Darter chicks on a nest in a live River Red Gum in the creek that joins Middle Lake to Third Reedy Lake. (Photo D. Cook)

Stakeholders: Barapa Barapa, Wemba Wemba, Goulburn-Murray Water, North Central Catchment Management Authority and Kerang Wetlands Ramsar Site Committee

Contact:  Damien Cook, restoration ecologist, Wetland Revival Trust, Email: damien@wetlandrevivaltrust.org

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Posted in agricultural lands, Assisted regeneration, Community involvement, Ecosystem services, Environmental watering, Fauna & habitat, Grassland/grassy understorey, Indigenous Knowledge, Indigenous land & sea management, Sclerophyll communities, Techniques & methodology, Victoria, Wetland

The Role of Swamps in Drought: Popes Glen Creek, Blackheath

Posted on 4 October 2020 by | Comments Off on The Role of Swamps in Drought: Popes Glen Creek, Blackheath

Alan Lane

Introduction

The important role of swamps in water storage and as regulators of stream flow has been well documented (10.1016/j.geomorph.2018.03.004). Previous EMR project summary reports on Popes Glen Creek, Blackheath, have described the establishment of a swamp on the former highly degraded and weed-infested silt plug at the headwaters of the creek.  (See links at end of this summary.)  That 18-year long project has been documented in “The Full Story”, https://dl.bookfunnel.com/ebgais2pxn and an 8-minute summary video can be viewed at https://www.youtube.com/watch?v=610sas330EQ

The recent severe drought in New South Wales provided the opportunity to monitor the water table in this swamp in the absence of rain and compare the impact on the swamp vegetation with that on more elevated and drier slopes nearby.

How we measured the water table. Six piezometers were installed at the start of this rehabilitation project, located about 50 m apart and midway between the edges of the long, rectangular silt plug. These went down to the bedrock, at depths of between 113 and 152 cm and were used to monitor water table depth and also for sampling water quality and stygofauna.

What we found. During periods of normal or above average rainfall (e.g. September 2019), the water table at each of these bore holes was typically at the depth below soil surface shown in Table 1.

Levels fell almost to bedrock during the drought (Oct 2019 – Dec 2019), before recovering after rains in January and February 2020 (Tables 1, 2). 

Table 1. Water table depths during normal and below-average rainfall periods.

Bore hole number
Depth below surface (cm) 1 2 3 4 5 6
Normal rainfall period (Sept 2019) 31 2 7 11 23 9
After drought period (Dec 2019) 103 106 121 103 – 123
After recovering rainfall (Feb 2020) 29 0 12 21 – 13

Table 2.  Rainfall, October 2019 – February 2020.

Month Rainfall (mm)1 5-year average (mm)2 % of average
September 2019 81.4 53.6 151.6
October 2019 23.8 76.7 31.0
November 2019 26.4 82.2 32.1
December 2019 0.4 69.5 0.6
January 2020 99.2 127.9 77.6
February 2020 560.4 183.6 305
  1. From Bureau of Meteorology, Mount Boyce, NSW
  2. From willyweather.com.au, Mount Boyce, NSW

During this period of extreme drought, the vegetation on the slopes above the Popes Glen swamp manifested extreme water stress in a way never before seen (Figs. 1, 2). Many of these extensive expanses of Coral Fern (Glycaenia dicarpa), stands of Fishbone Water Fern (Blechnum nudum) and individual Black Tree Fern (Cyathea australis) plants have not recovered and now appear unlikely to do so.

Figure 1. Expanses of severely water-stressed Glycaenia dicarpa on slopes above the Popes Glen swamp.

Figure 2. Many of the Blechnum nudum and Cyathea australis on slopes above the swamp have failed to recover.

In marked contrast, the vegetation in the swamp area (Fen Sedge (Carex gaudichaudiana), Tassel Sedge (Carex fascicularis), Tall Spikerush (Eleocharis sphacelata) and Juncus sp.) remained lush and vigorous (Fig. 3), suggesting it was sustained by the supply of water retained in the substrate.

This supply was progressively depleted during the drought and the water table had fallen almost to bedrock before the rains in January (Tables 1, 2).

Figure 3. Vegetation in the Popes Glen swamp remained lush throughout the drought.

Implications. It seems inevitable that this water supply would have been completely exhausted had the 2019-2020 drought lasted longer. Temperate Highland Peat Swamps on Sandstone (THPSS), including the Popes Glen swamp, appear threatened by the even more prolonged droughts anticipated as climate disruptions due to global heating become more marked.

Acknowledgements. This work was supported by Blue Mountains City Council and funding from the Environmental Trust of NSW.

Contact. Alan Lane alanlane388@gmail.com

See also EMR Project Summaries:

 

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Posted in Bush regeneration, climate change, Community involvement, New South Wales, Restoration & management theory, Wetland

Ecological restoration in urban environments in New Zealand – UPDATE of EMR feature

Posted on 22 October 2019 by | Comments Off on Ecological restoration in urban environments in New Zealand – UPDATE of EMR feature

Bruce Clarkson, Catherine Kirby and Kiri Wallace

[Update of EMR feature  – Clarkson, B.D. & Kirby, C.L. (2016) Ecological restoration in urban environments in New Zealand. Ecological Management & Restoration, 17:3, 180-190.  https://onlinelibrary.wiley.com/doi/10.1111/emr.12229]

Key words: urban ecology; restoration; indigenous biodiversity; New Zealand

Figure 1. Kauri dieback disease is affecting individual trees (left). [Photo Nick Waipara]

Introduction. Our 2016 EMR feature reviewed the state of research and practice of ecological restoration in urban environments in New Zealand. We concluded that urban restoration can influence and support regional and national biodiversity goals. We also observed that research effort was light, lacking interdisciplinary breadth and may not be sufficiently connected to restoration practice to ensure long-term success of many projects.

While it is only three years since that review was published, urban ecological restoration continues to grow and evolve, and the policy setting and political context have changed significantly. New threats and opportunities have emerged. The spread of a dieback disease and the more recent arrival of myrtle rust, rapid uptake of Predator Free 2050, emergence of the One Billion Trees programme, a surge in housing and subdivision development, and a potentially more supportive policy framework are all major factors.

Threats and opportunities. Kauri dieback disease is severely affecting urban kauri forests and individual Kauri (Agathis australis) trees in Auckland and other northern North Island urban centres (Fig. 1). Large forest areas adjoining Auckland, including most notably the Waitākere Range and large parts of the Hunua Range, are now closed to the public, preventing access to popular recreational areas. The dieback is caused by a fungus-like pathogen Phytophtora agathicida that is spread through soil movement. The disease may have arrived from overseas although this is uncertain. There is no known cure but research efforts are underway to find a large-scale treatment option.

Myrtle rust (Austropuccinia psidii) was first found on mainland New Zealand in May of 2017, probably arriving by wind from Australia. Myrtle rust threatens many iconic New Zealand plant species in the family Myrtaceae including Pōhutukawa (Metrosideros excelsa), Mānuka (Leptospermum scoparium), Rātā (Metrosideros robusta), Kānuka (Kunzea spp.), Waiwaka (Syzygium maire) or Swamp maire, and Ramarama (Lophomyrtus bullata). These species are all used to a greater or lesser extent in restoration planting or as specimen trees or shrubs in urban centres, depending on amenity or ecological context. Mānuka is widely used as a pioneer or nurse crop for native forest restoration and is critical to the economically important mānuka honey industry. Waiwaka is a feature of many swamp forest gully restoration projects in Hamilton and this would be a significant setback if they were badly affected. The impact of myrtle rust is still not clear but experience from Australia suggests it may take several years before it reaches population levels sufficient to cause significant damage.

Figure 2. With rapid housing developments in New Zealand, it is important that urban restoration projects are well-planned and efficiently carried out to provide residents with greenspaces to benefit their cultural, health and wellbeing practices. [Photo Catherine Kirby]

In response to a range of housing issues characterised by many as a New Zealand housing crisis, the previous and current government has embarked on several major initiatives to increase the housing stock. A $1B Housing Infrastructure Fund (HIF) was established in October 2016 with provision for interest free loans to local government to enable opening up of new large areas of housing. Many urban centres including Auckland, Tauranga, Hamilton and Queenstown made early applications to the fund. Hamilton City Council was successful in obtaining $290.4 M support for a new greenfield subdivision in Peacocke on the southern edge of the city. This subdivision is intended to enable development of some 3700 houses over the next 10 years and 8100 in 30 years. Approximately 720 ha of peri-urban pastoral agricultural land would eventually be developed (See summary). Coupled with this, and already in progress, is the construction of the Southern Links state highway and local arterial road network. The first proposed subdivision Amberfield covers 105 ha and consent hearings are currently in progress. The environmental impacts of the proposal and how they might be mitigated are being contested. In brief, survival of a small population of the critically endangered Long-tailed Bat (Chalinolobos turberculatus) is the main environmental focus but other aspects including the extent of greenspace and ecological restoration required for ecological compensation are being considered (Figs. 2, 3). With strong political pressure to solve the housing crisis in Hamilton and in other urban centres, making adequate provision for greenspace, especially urban forest, and preventing environmental degradation and indigenous biodiversity decline will be a major challenge.

Figure 3. Aerial photo of Waiwhakareke Natural Heritage Park (65 ha), an award-winning and ongoing ecological restoration project situated on the edge of urban Hamilton. [Photo Dave Norris]

The Predator Free 2050 (PF2050) programme which gained government (National) approval in 2015, aims to eradicate Stoat (Mustela erminea), Ship Rat (Rattus rattus), Norway Rat (Rattus norvegicus) and Possum (Trichosurus vulpecula) from the whole of New Zealand by 2050 (Department of Conservation 2018). PF2050 is now gaining significant traction in urban environments (Figs. 4, 5) with many urban centres having good numbers of community-led projects underway (See PFNZ National Trust map). Crofton Downs in Wellington was New Zealand’s first predator-free community project. Led by Kelvin Hastie this project has effectively reduced predator numbers to the point that some sensitive native birds e.g. Kākā (Nestor meridionalis), have begun to nest in this suburb after an absence of more than 100 years (See RNZ report). Also in Wellington, the Miramar Peninsula (Te Motu Kairangi) has become a focus, because of its advantageous geography, with a goal to make the area predator free by 2019. Possums had already been exterminated in 2006 (www.temotukairangi.co.nz).

Figure 4. John Innes (Wildlife Ecologist, Manaaki Whenua Landcare Research) demonstrating trapping success. Removing pest mammals reduces predation, and also frees up the habitat and resources for our native fauna and flora to flourish. [Photo Neil Fitzgerald]

The One Billion Trees (1BT) programme was initiated by the new coalition government (Labour, NZ First, Greens) in 2017 with $238M released in 2018 for planting of both exotic and native trees across mixed land use types. It is not clear yet whether urban forest projects have received funding support but the guidelines suggest there is no reason why restoration of native forest in urban settings would not be eligible. While the emphasis is on exotic tree plantations, native species and long-term forest protection are increasingly being considered as viable options by the newly established government forestry agency Te Uru Rākau.

The policy setting for ecological restoration in urban environments is potentially becoming more favourable with the draft National Policy Statement on Indigenous Biodiversity (NPSIB) currently in review and the New Zealand Biodiversity Strategy under revision (See terms of reference). The draft NPSIB emphasises restoration of indigenous habitat in biodiversity depleted environments. Specifically, Policy 19: Restoring indigenous biodiversity depleted environments, recommends a target for indigenous land cover, which in urban areas and peri-urban areas must be at least 10 per cent. The revision of the New Zealand Biodiversity Strategy seems likely to give more emphasis to landscape scale restoration including urban environments.

Figure 5. New Zealand native lizards are extremely vulnerable to mammalian predation (e.g. mice, hedgehogs, ferrets, cats) as well as habitat destruction (e.g. new urban developments). [Photo Tony Wills]

Research update. Using the same targeted Google Scholar search method as reported in the EMR feature we have found 18 new peer reviewed papers published between 2015 and July 2019 (see updated bibliography) that are strongly focused on restoration in New Zealand urban environments. The single paper noted for 2015 was missed in our previous search. Again, we have not included books, book chapters or grey literature. This compares very favourably with the total 27 papers listed in our 2016 review of which more than half dated from 2009. An increasing publication rate confirms increasing interest and research efforts in aspects of urban ecological restoration. While most of the publications remain in the ecological science realm there are now some informed by other disciplines including engineering, psychology, landscape architecture and health sciences.

Most notably since our 2016 review, a new government-funded (Ministry of Business, Innovation and Employment) research programme, People, Cities and Nature, began in November of 2016. This four-year $823 k per annum research programme ends in October of 2020 unless a funding rebid to be submitted in March 2020 is successful. The programme undertakes multidisciplinary research in nine NZ cities via six inter-related projects: restoration plantings; urban lizards; mammalian predators; Māori restoration values; green-space benefits and cross-sector alliances. While the emphasis was on the ecological science of urban restoration at the outset, the programme has become increasingly involved in understanding the multiple benefits of urban ecological projects including social cohesion and health and recreation benefits. The need to connect restoration research and practice has been met by undertaking multi-agency and community workshops involving researchers and practitioners in five cities to date with a further four scheduled before the programme ends.

Acknowledgements. The People Cities and Nature research programme is funded by the Ministry of Business Innovation and Employment under grant number UOW1601.

Information. Bruce D. Clarkson, Environmental Research Institute, University of Waikato, Hamilton, New Zealand bruce.clarkson@waikato.ac.nz; Catherine L. Kirby, Environmental Research Institute, University of Waikato, Hamilton, New Zealand catherine.kirby@waikato.ac.nz; and Kiri J. Wallace, Environmental Research Institute, University of Waikato, Hamilton, New Zealand kiri.wallace@waikato.ac.nz.

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Posted in Community involvement, Cultural & socio-economic issues & solutions, Education & communication, EMR 20th anniversary updates, Fauna & habitat, New Zealand, Pest species, Podocarp forest, reconstruction, Threatened species & communities, Uncategorized, Urban ecosystems, Wetland

Still repairing wetlands of the Lower Murray: continuing the learning – UPDATE of EMR feature

Posted on 3 October 2019 by | Comments Off on Still repairing wetlands of the Lower Murray: continuing the learning – UPDATE of EMR feature

Anne Jensen

[Update to EMR feature – Jensen, Anne (2002) Repairing wetlands of the Lower Murray: Learning from restoration practice. Ecological Management & Restoration, 3:1, 5-14. https://onlinelibrary.wiley.com/doi/10.1046/j.1442-8903.2002.00092.x]

Key words:         Environmental water requirements, regeneration, wetlands, black box seedlings, Lower Murray Valley

Figure 1. Location of the Lower Murray Valley in South Australia (Map A. Jensen)

Introduction. As highlighted in the original EMR feature this summary is updating, in the Lower Murray Valley 1100 wetlands have been identified in 250 hydrologically-linked complexes (Fig. 1). They have undergone major changes to their water regime over the last 100 years, altering the timing, frequency and duration of floods. Wetlands at lower elevations have become permanently flooded by stable river levels and wetlands at higher elevations are ‘droughted’ by much reduced flooding. All would benefit from environmental watering, to fill gaps in breeding and regeneration cycles.

Our 2002 feature showed that, from 1998 to 2002, the not-for-profit conservation company Wetland Care Australia coordinated on-ground projects to repair priority wetlands in the Lower Murray. The Gurra Gurra project was the largest of these projects, with engineering works at 17 sites to restore multiple flowpaths through the 3000 ha floodplain complex.

Key funding from the National Heritage Trust terminated in 2002 and Wetland Care Australia relocated in 2003 to northern New South Wales, where project funding for wetland projects was still available. However, individuals involved with the Wetland Care Australia projects remained in the Lower Murray Valley in other jobs, so the intellectual property was retained and wetland conservation activities continued.

In 2002, the extent and severity of drought conditions in the Murray River Valley were just being recognised. By 2004, a survey estimated that >75% of the two main tree dominants in floodplain woodlands –  River Red Gum (Eucalyptus camaldulensis) and Black Box (E. largiflorens)  – were dead, dying or extremely stressed along 700 km of the Murray River Valley . The Millenium Drought (2000-2010) caused extreme stress to both ecological and human communities. Government agencies commenced emergency environmental watering from 2004 through the Living Murray program to limit catastrophic damage at eight iconic sites but millions of mature eucalypts were lost from floodplain woodlands along river valleys.

The Millenium Drought changed the governance context radically, with the Water Act 2007 establishing a new Murray-Darling Basin Authority and the Basin Plan. The Commonwealth Environmental Water Holder (CEWH) was able to purchase water for environmental use.

Nature delivered life-saving floods in 2010-12, which broke the drought and sent flows through the Gurra Gurra complex flowpaths, so the works completed back in 2000 finally fulfilled their function (Fig. 2). Water flowed through the pipes at Tortoise Crossing for 170 days in 2010-11 and again for 71 days in 2012.

Figure 2. The sign at the key Tortoise Crossing flow path explains that replacing three pipes with 160 pipes back in 2000 now allows 50 times more flow when the river floods, as seen at the flood peak in December 2016 (Photos A. Jensen)

The sequence of floods led to mass germination of Black Box at medium floodplain elevations, with mass River Red Gum seedlings at lower elevations. A range of studies show that the survival of these seedlings is critical to fill age gaps and replace the losses from the Millenium Drought, as survival rates from germination events in the 1970s and 1990s were very poor and the last successful mass recruitment of Black Box in the Lower Murray Valley was from the 1955-56 floods.

Following the floods in 2010-2012, conditions were dry in 2013-15 and the fields of mass seedlings began to dry out and die. A further short flood in 2016 watered the surviving fields of Black Box seedlings for at least two weeks, adding to prospects of survival and flowing through the Tortoise Crossing pipes for 75 days. However, conditions in 2018-19 and into summer 2019-20 are once again extremely dry, with stress appearing in mature trees and saplings dying off. The Lower Murray Valley is still recovering from the Millenium Drought, thus needing more frequent watering over a sequence of years to bring mature trees back to health and full seed production, so this is a significant setback.

Further works and activities since 2002. Since 2008, the environmental charity Nature Foundation SA (NFSA) has been undertaking environmental watering projects on smaller, privately-owned sites in the Lower Murray, many from the original Wetland Care Australia list. In the Lower Murray Valley, water needs to be lifted up to 3 m from the river channel to reach wetlands on the floodplain, requiring costly energy. This is done using irrigation techniques, including pumps, pipes and sprinklers. These smaller projects complement government agency projects using major infrastructure to deliver environmental water to much larger wetland complexes.

In 2008-09, the primary purpose was to acquire water and use it to limit extreme environmental damage in the drought. In 2009 NFSA provided supplementary water for Little Duck Lagoon, one of the sites from the Wetland Care Australia Gurra Gurra project.

From 2012-19, NFSA has held a contract partnered with the Commonwealth Environmental Water Holder (CEWH) to deliver up to 10 GL/y of environmental water to selected sites. A priority for the NFSA Water for Nature program has been to sustain the mass germination triggered by the 2010-12 floods, watering fields of seedlings and saplings so they can fill the very large gap in age structure of Black Box populations. Stressed mature Black Box trees are being watered to improve their condition and volumes of seed produced. While delivering water to a defined wetland is relatively simple, with water pumped to an inlet point and allowed to pool in the wetland, watering scattered fields of seedlings and saplings on relatively flat floodplain land is a challenge, especially when they are in gaps between mature trees. The solution has been to use high-throw sprinklers (simulating rainfall) and operating them at night, to allow soakage into clay soils and to avoid evaporative loss during the day.

Since 2008, NFSA has delivered almost 13 GL of water to 97 watering sites in 20 wetland complexes, covering 27 different ecological targets across 12 habitat types. A total of 4.9 GL was delivered to 15 sites in 2017-18 and 1.55 GL was delivered in 2018-19 to 25 sites covering 126 ha. Rolling 5-year watering plans have been developed for each site, able to respond to annual water availability, Basin-wide priorities, environmental water requirements, climatic conditions, site watering history and feasibility of delivery.

One of the NFSA sites is Lyrup Lagoon in the Gurra Gurra complex, being watered to reduce accumulated salinity from groundwater inflows. Importantly, the infrastructure of the Central Irrigation Trust was used to deliver water to the lagoon. Thus, local irrigators are partners in delivery of water for regional environmental benefits and river health.

Figure 3. Watering guidelines developed by the Water For Nature program for stressed and healthy woodlands, for (a) River Red Gum and (b) Black Box (Water for Nature).

Further Results. The initial watering guidelines reported in the original EMR feature have been expanded through research and monitoring of responses to watering events, developing guidelines for timing and frequency of wetting and drying cycles to promote recovery in mature trees and support germination and survival of seedlings. These have been applied for each site in the rolling 5-year watering plans, which then determine the annual list of sites due for watering (see NFSA 5 year strategy and Fig. 3).

Watering by NFSA 2013-2019 has sustained Black Box seedlings and saplings through four dry summers, with watered plants 2-3 times taller than non-watered plants (Fig. 4). The Water For Nature monitoring report shows that, at NFSA sites, mature Black Box trees that have received periodic environmental water as determined by their 5-year watering plan during 2015-2019 were 21-46% (average 36%) better in health than adjacent non-watered sites, with denser, more vigorous canopies and the relative improvement was greatest during hotter and drier periods. The watering events thus provided water between natural floods to sustain growth in saplings and crop cycles in mature trees. Watering at other NFSA sites has provided vital habitat for vulnerable and endangered fauna including the Murray Hardyhead (Craterocephalus fluviatilis), Southern Bell Frog (Litoria raniformis), Regent Parrot (Polytelis anthopeplus) and Latham’s Snipe (Gallinago hardwickii).

Figure 4. Watered River Red Gum saplings at Thiele Flat, Loxton; November 2013 (top) and March 2018 (bottom). Note 2016 flood level mark on foreground trees (Photos A. Jensen)

Lessons learned and future directions. The significant benefits of environmental water have been demonstrated at NFSA’s Water For Nature sites, for floodplain vegetation communities and in temporary wetlands. Evolving research indicates that watering in late spring-early summer mimics peak flows in the natural water regime, coinciding with highest chances of breeding and germination events and thus ecologically ideal timing (See bibliography). Benefits are increased if seasonally filled wetlands are topped up in early summer, to ensure sufficient duration to sustain frog and waterbird breeding.

As well as ideal timing, studies have shown that watering at any time of the year can be beneficial, including enhancing soil moisture storage in the unsaturated zone and sustaining volume in bud and fruit crops. A key finding has been that watering in late autumn-early winter sustains soil moisture, priming sites to give an enhanced response to watering in the following spring-summer.

However, dry climatic conditions and political pressures to minimise water recovery volumes are combining to reduce availability of environmental water, with only very highest priority sites likely to receive water in the 2019-20 water year. Environmental water cannot create floods, it can only provide water to selected priority sites during dry times and enhance the benefits of any natural floods. Current volumes can only meet the requirements of a limited number of sites, leaving many sites without the water needed to sustain them through dry times or to recover from the severe impact of the Millenium drought.

Bureaucratic processes for approvals also hinder effective delivery of environmental water. With the water year coinciding with the financial year from July to June, water delivery stops in June to allow water accounts to be finalised. Approval to water in the following year can take 2-3 months, meaning no water can be delivered during the winter months for priming, missing the advantage of low evaporation rates and higher chances of piggy-backing on rainfall events.

Funding for environmental projects tends to be short term, leading to job insecurity for project managers, loss of continuity and project knowledge, and inability to complete watering sequences. Very significant volunteer resources are required to make these watering projects happen, including inputs from landholders who have donated electricity connections to the floodplain, transported diesel to re-fuel pumps, loaned pumps, tractors and irrigation equipment, plus use of irrigation and local government infrastructure to deliver water, and physical assistance and maintenance from local volunteer groups.

Practical on-ground watering knowledge is maturing well; what is needed now is sufficient water and ongoing consistent funding to support projects to deliver minimum environmental water requirements for the wetlands of the Lower Murray Valley. The pipes at Tortoise Crossing, installed in 2000 and only flooded twice, are more than ready for the next high flows to pour through!

Stakeholders and Funding bodies. The monitoring project was supported as part of the project Ecological Responses to Environmental Watering in the South Australian River Murray Valley, assessing the benefits of salinity interception schemes on floodplain vegetation, coordinated by Australian Water Environments for SA Water from March 2015 to June 2017. Continuing funding for monitoring in 2017-2019 was provided in a grant from the Ian Potter Foundation to Nature Foundation SA, as well as funding from the Commonwealth Environmental Water Holder (2018-19). Water for the environmental watering projects studied here was provided through annual allocations of water from the Commonwealth Environmental Water Office to Nature Foundation SA.  Water delivery was managed by the NFSA Water For Nature program through Program Manager Natalie Stalenberg. Practical support and site access was provided by Steve Clark, landholder and committee member for Water for Nature program, and landholders John and Bronwyn Burford.

Contact. Dr Anne Jensen, Environmental Consultant; Volunteer member, Water for Nature Committee, Nature Foundation SA; part-time consultant Wetland Ecologist for Water for Nature Program of Nature Foundation SA (7 Ford Street, Maylands SA 5069, Australia; Tel: +61 407 170 706; Email: ajensen@internode.on.net

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Posted in agricultural lands, Assisted regeneration, Community involvement, Ecosystem services, EMR 20th anniversary updates, Environmental watering, Fauna & habitat, Freshwater aquatic, South Australia, Techniques & methodology, Threatened species & communities, Wetland

Ecological restoration and rehabilitation at Sydney Olympic Park – UPDATE to EMR feature

Posted on 19 September 2019 by | Comments Off on Ecological restoration and rehabilitation at Sydney Olympic Park – UPDATE to EMR feature

Jennifer O’Meara and Kerry Darcovich

[Update to EMR feature – O’Meara, Jennifer and Kerry Darcovich (2015) Twelve years on: Ecological restoration and rehabilitation at Sydney Olympic Park, Ecological Management & Restoration, 16:1, 14-28. https://onlinelibrary.wiley.com/doi/10.1111/emr.12150 ]

Keywords: Environmental management, ecological management, threatened species, Habitat management , woodland birds, Green and Golden Bell Frog

Introduction. The 2015 EMR feature described ecological restoration and management works at Sydney Olympic Park, a large urban park containing both remnant and constructed landscapes that underwent significant restoration in preparation for the 2000 Olympic Games. Sydney Olympic Park supports a rich natural environment that includes over 250 native animal species, over 400 native plant species and three endangered ecological communities.  The high ecological values of the Park have resulted in 304 hectares (nearly half of the Park) being zoned under NSW planning legislation for environmental conservation and management.  Key habitats include estuarine and freshwater wetlands, remnant eucalypt forest, saltmarsh meadows and woodland bird habitats.

The Park’s biodiversity is of high conservation significance, and makes a significant contribution to the social and economic values of the Park.  The Park’s natural environments enrich visitor experience, provide a living classroom for environmental education programs, and attract businesses and residents seeking proximity to nature. This project began in 2000 when management transferred from a construction phase after the Sydney Olympic Games to an active management phase and is supported by an extensive long term ecological monitoring program. This update summarises new works and outcomes since 2016.

Further works undertaken. The introduction of new ecological infrastructure for frog habitat targets threatening processes of predation by introduced fish and increasing water availability.  Fish-proof fences have been introduced to wetlands where the predatory fish Gambusia (Gambusia holbrooki) is present in Green and Golden Bell Frog (Litoria aurea) habitat (Fig 1). The fences are placed around ponds or pond clusters and then the pond is dried out and refilled with fish-free water. Constructed of sediment fences 600mm high and embedded in the ground, these fences stretch to a maximum of 200m and have successfully restricted the fish from ponds for more than three years.

Figure 1.  Gambusia fence

In order to reduce the impact of bird predation on tadpoles in key breeding ponds, bird netting secured by wire cables to the ground and supported by hoops has been introduced.  The netting is also used as a response to the sighting of Green and Golden Bell Frog tadpoles in ponds with Sydney Olympic Park staff deploying temporary netting where successful breeding has occurred. Netting is left on the pond until all metamorphs have dispersed from the pond then removed.

Restoration of the water-holding capacity and connectivity of bell frog habitat in the Brickpit and Kronos Hill has been improved with temporary ponds being created with tarps (Fig 2). The aim is twofold – to extend the number of predator-free, drought refuges, important for adult female frogs and metamorphs and to ensure frog corridors maintain connectivity.  More than 10 tarp ponds have been created and have an expected life span of 3-6 years and are very budget friendly. Annual monitoring has shown a remarkable uptake of these ponds by the Green and Golden Bell Frog.

Figure 2.  Tarp pond with netting

Further results to date. The Parks ecological monitoring program is ongoing and now entering the 16th consecutive year for birds, 15th for reptiles and 21 years for the Green and Golden Bell Frog. In 2018-19 the fourth woodland bird survey was completed, a four yearly assessment of the status of woodland birds and vegetation management at Sydney Olympic Park. Fifteen quadrats are surveyed over the spring and autumn seasons to measure bird communities which is then compared to change in vegetation structure. Results show that small birds were strongly, positively correlated with shrub cover, but strongly negatively correlated with tree cover and Noisy Miner (Manorina melanocephala).  Since 2006, Sydney Olympic Park Authority has implemented a habitat modification program aimed at increasing the structural diversity and complexity of key areas of the Park to support woodland birds. The program seeks to build connectivity between key woodland bird habitats with the form of habitat enhancement varying depending on site characteristics. The survey shows that this program is successfully creating suitable habitat for this group of birds.

With the prospect of greater demands by the public to access the Park at all hours (see below), Sydney Olympic Park staff have recently collected baseline light level readings from across the Park to inform decision making.  Data on lux levels and light source was collected from over 160 sites ranging from car parks to mangrove creeks. The main drive of the survey was to collect information on light spill into sensitive habitat areas where darkness is a key ecological feature. The survey led to a review of lighting and identification of where lights could be switched off or timed to decrease light impacts. The findings will also inform future planning for illumination within the Park.

Lessons learned and future directions. Sydney Olympic Park is part of a rapidly densifying area with the 30,000 residents currently located within a 3km radius forecast to increase to approximately 100,000 in ten years. Due to the density of housing, Sydney Olympic Park will be/is already the local park for this community, leading to increasing demand for recreation and access to the Parklands. This presents great opportunities for more people to connect with nature and to incorporate community education and sustainability into Park programs.  A new program known as Park Care has been launched recently and currently rolls out community clean up and revegetation activities.

The flipside of this rapid population increase is increasing risk of disturbance to ecologically sensitive areas which needs to be considered and mitigated carefully as the Park continues to evolve. Ensuring the Park is able to sustainably meet this demand is a focus for management now and into the future. New habitat management plans for ecologically sensitive areas of the Park are being developed to better-guide biodiversity conservation on a precinct level. Ongoing ecological management works, and managing the impacts of human disturbance, will be essential to conserving the ecological values of the Park.

Contact. Jennifer O’Meara, Parklands Ecologist, Sydney Olympic Park Authority, 5 Olympic Boulevard, Sydney Olympic Park 2127 NSW, Australia. Email: Jenny.omeara@sopa.nsw.gov.au

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Posted in Assisted regeneration, Ecosystem services, Education & communication, EMR 20th anniversary updates, Fauna & habitat, Freshwater aquatic, New South Wales, Pest animal issues & solutions, Pollution issues & solutions, Sclerophyll communities, Techniques & methodology, Threatened species & communities, Urban ecosystems, Weed issues & solutions, Wetland

Restoration of Wollongong’s Tom Thumb Lagoon 25 Years On: UPDATE of EMR feature.

Posted on 18 September 2019 by | Comments Off on Restoration of Wollongong’s Tom Thumb Lagoon 25 Years On: UPDATE of EMR feature.

 Nicholas Gill

[Update of EMR feature: Gill, Nicholas (2005) Slag, steel and swamp: Perceptions of restoration of an urban coastal saltmarsh. Ecological Management & Restoration, 6:2, 85-93 https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2005.00224.x]

Keywords. coastal wetlands, urban green space, pollution, mangroves, volunteers.

Figure 1. Tom Thumb Lagoon and Greenhouse Park (a) 2008 and (b) 2017. (Source Google Earth)

Introduction. The 2005 feature was drawn from restoration work my students and I became involved in during the early 2000s at Tom Thumb Lagoon (TTL) – an estuarine wetland close to Wollongong’s CBD and adjacent to the Port Kembla industrial area and harbour. By that point Wollongong City Council (WCC), the Bushcare group Friends of Tom Thumb Lagoon (FTTL), industry, Conservation Volunteers Australia (CVA), and many volunteers had been variously working on the site since the early 1990s. After decades of impacts from industrial development, waste disposal, and neglect, this significant restoration effort encompassed removing landfill, reshaping the wetland with channels and shallow benches, revegetation, weeding, and the construction of access and viewing points. By the time we became involved and I wrote the 2005 paper, TTL and the adjacent Greenhouse Park (GHP; Fig 1), were substantially revegetated, aesthetically improved, and the saltmarsh wetlands were seen as ecologically valuable. Participants and stakeholders in the restoration project perceived that substantial progress and improvement had been made. They also perceived, however, that the project suffered from some issues common to such endeavours such as a lack strategic planning and monitoring of ecological outcomes.

Since this time, restoration and other work has continued at TTL and at GHP. The story of what has happened, however, is one of the dynamic and contextual nature of sites such as this. This is true in a biophysical sense of ongoing vegetation change, particularly the spread of Grey Mangrove (Avicenna marina), a native plant previously not occurring on the site but planted for perceived environmental benefits either in the 1990s, or around 2000. This spread (into what was previously saltmarsh and mudflats) arises from past decisions and, while providing benefits, is now potentially causing new problems as well as continuing debates about choices in restoration.  The social context has also been dynamic and influential, as priorities have shifted, as the funding environment has altered, and as the people and groups involved have changed. Finally, Tom Thumb Lagoon remains affected by the legacy of the industrial history of its location. Past waste disposal practices in the absence of regulation have led to pollution problems that have become of greater concern since the early 2000s.

Activities at Tom Thumb Lagoon and Greenhouse Park Today. The wetland area itself is adjacent to a capped waste disposal site that operated from the 1940s until the mid-1970s. This area is known now as Greenhouse Park and is being managed and developed as urban green space with more focus on fostering urban sustainability practices; any restoration work is nested within these foci. TTL and GHP were always associated through overlap between FTTL and GHP staff, and GHP facilities were a base for TTL activities. Today, however, personnel have changed, FTTL no longer exists and its key members are no longer associated with TTL, and TTL/GHP are managed as one site to a greater extent. The result of these factors, and of the achievements already made at TTL, have been a shift towards an emphasis on activities at GHP and a change in TTL activities from active restoration to maintenance. It is now GHP volunteers and associated WCC staff who undertake and oversee work at TTL. At GHP WCC has expended considerable resources in tree planting and expanding a permaculture garden. There is a shelter, outdoor kitchen, and pizza oven for volunteers, WCC and Wollongong firms compost green and food waste, and there are hopes for public, tourism, and event use. Around ten volunteers work at the site weekly. For the GHP staff and volunteers, activities at TTL itself today are largely limited to weeding, picking up litter, and feral animal control. Weeds and litter remain problems, partly due to TTL’s location at the bottom of an urban catchment. In addition, since 2005, frog ponds were installed at the eastern end of TTL for the endangered Green and Golden Bell frog (Litoria aurea), however, it is not clear if the ponds are effective. The non-native Giant Reed (Arundo donax) also remains well established at this end of TTL despite control attempts.

Shifts in support have meant that CVA bowed out of work at TTL/GHP in 2012. Previously their involvement had been via a wetlands program that relied on support from both industry (including Bluescope and NSW Ports, both operating adjacent to TTL) and government programs. Until 2012, in conjunction with WCC, CVA were revegetating the southern slopes of GHP (marked A in Fig. 1) and were removing weeds and litter from the saltmarsh. However, the funding that CVA relied on declined such that CVA was unable to continue at TTL/GHP.

Figure 2.  Eastern end of TTL looking south (a) 2002 and (b) 2019 (Photos Nick Gill)

The Mangroves are Coming. Apart from further revegetation at GHP, the most significant vegetation change at TTL has been the spread of Grey Mangrove. While approval to thin this species has been obtained in the past and some thinning did occur, it has not mitigated their current spread and density. Grey Mangrove spread is clearly seen for the period from 2002 to 2019 in Fig 2 which shows the eastern end of TTL and the southern end of the channel known as Gurungaty Waterway. Aerial photos further reveal changes from 2008-2017 where the largely east-west spread of mangroves along channels in TTL can be seen (marked B in Fig 1). Significant spread can also be seen north-south spread along Gurungaty Waterway over this period (marked C in Fig 1). As the 2005 paper records, not long after Grey Mangrove was planted in the late 20th or early 21st Century, its expansion was  soon causing concern for its consequences for the site’s mudflats, saltmarsh and tidal habitats although it appears to have largely remained confined to the channels and has no doubt generated some environmental benefits. In terms of its consequences on bird habitat, the long observations of local birdwatchers suggest that the expansion of Grey Mangrove has reduced the incidence of waders and shorebirds, particularly Black Winged Stilts (Himantopus himantopus) and also waterfowl and herons. Nonetheless, observers report that Grey  Mangrove colonisation is providing habitat for other birds, such as the Sacred Kingfisher (Todiramphus sanctus), the Nankeen Night-Heron (Nycticorax caledonicus), and the Striated Heron (Butorides striata). Elsewhere across more upland areas of TTL and GHP, the expansion of tree planting across GHP and TTL has seen a shift to birds favouring woodland habitats.

The expansion of Grey Mangrove is also implicated in flood risk, especially for the catchment of Gurungaty Waterway. A 2019 review of the Wollongong City Flood Study, suggests that low elevations and channel infrastructure, combined with sedimentation and flow limitations associated with the now dense mangroves (Fig. 3), have increased the likelihood of flooding in the urban catchment.

Figure 3.  Southern Gurangaty Waterway in (a) 2002 and (b) 2019. Note the steel footbridge on left of each photo. (Photos Nick Gill)

Industrial Legacies. The 2005 paper notes that saltmarsh restoration was an important part of the TTL work and that stakeholders saw the saltmarsh as a significant ecological element of TTL. Since 2004 coastal saltmarsh has been listed as an Endangered Ecological Community in NSW. From 2006, saltmarsh degradation prompted WCC to monitor the saltmarsh and analyse groundwater and soils.  This showed that the degradation was likely associated with ammonia leaching from the tip and causing nitrate pollution, and also with a hydrophilic layer of iron hydroxide in the soil causing waterlogging and contaminant absorption. The possible origins of this layer include past waste disposal practices from metal manufacturing.

These, however, are not the only legacies of past unregulated waste disposal and industrial activity. TTL is now a declared site of ‘significantly contaminated land’ by the NSW EPA. The 2018 declaration notes that site is contaminated by ‘polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons and other mixed contaminants from multiple sources including coal tar and lubricant oils’. At TTL elements of these can be visible as a film on the water surface and are among the substances leaching from GHP. Such substances are carcinogenic and exposure can cause a range of health problems. The presence of these materials in the groundwater has been known since the 1990s but from 2013 WCC began to monitor and map these materials. Monitoring points were installed along the wetlands at base of the old tip. Various remediation options for these contaminants, as well as for the nitrates and iron hydroxide layer, were proposed but action was not taken at this time for various reasons including disruption to the wetland, costs, and uncertainties regarding pollutant interception. As of 2019, the site is subject to a ‘Voluntary Management Proposal’ by WCC which includes the preparation of a remediation action plan by late 2019.

Future Directions. The last fifteen years have seen some aspects of restoration, such as tree planting, proceed and expand. By some measures this is continued progress of the original project. TTL/GHP is now a well-established urban green space with environmental and amenity value. However, concerns from the early 2000s about volunteer succession, the absence of a catchment approach to management, and the need to think more strategically about ecological trade-offs between management options have been realised to some extent. The spread of Grey Mangrove is the clearest example of this. In part, some of this is perhaps inevitable for a site with the history and setting of TTL/GHP; the management context has changed, participants and stakeholders have changed, and difficult legacy issues have assumed greater prominence and cost. Nonetheless, the challenge to manage the site with a clear strategy and goals remains.

Acknowledgements: For assistance with this update, I am indebted to several past and present WCC staff, particularly Mike McKeon. I was also helped by Adam Woods, formerly of CVA, and birdwatchers Penny Potter, Terrill Nordstrom, and David Winterbottom.

Contact. Nicholas Gill, School of Geography and Sustainable Communities Faculty of Social Sciences, University of Wollongong NSW 2522 Australia, Email: ngill@uow.edu.au

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Posted in Coastal & marine, Community involvement, Ecosystem services, EMR 20th anniversary updates, Fauna & habitat, Integrating ecosystems & industries, New South Wales, Pollution issues & solutions, Urban ecosystems, Wetland

Restoration and conservation in an iconic National Park – UPDATE of EMR feature

Posted on 27 June 2019 by | Comments Off on Restoration and conservation in an iconic National Park – UPDATE of EMR feature

David Lindenmayer, Chris MacGregor, Natasha Robinson, Claire Foster, and Nick Dexter

[Update of EMR feature – David B. Lindenmayer, Christopher MacGregor, Nick Dexter, Martin Fortescue and Peter Cochrane (2013)  Booderee National Park Management: Connecting science and management.  Ecological Management & Restoration, 14:1, 2-10. https://onlinelibrary.wiley.com/doi/10.1111/emr.12027]

Keywords: Invasive animal and plant control, reintroduction, monitoring

Introduction. Booderee National Park is an iconic, species-rich, coastal reserve that supports a range of threatened and endangered native animals and plants. Several key management actions have been implemented to promote the conservation of biodiversity in Booderee National Park. These include the control of an exotic predator (the Red Fox Vulpes vulpes), the control of highly invasive Bitou Bush (Chrysanthemoides monilifera subsp. rotundata), the management of fire, and the reintroduction of previously extinct native mammals. A key part of work at Booderee National Park has been a long-term monitoring program that commenced in late 2002 and which has aimed to quantify the effectiveness of major management interventions, including the four listed above. The monitoring program has documented the long-term trajectories of populations of birds, arboreal marsupials, terrestrial mammals, reptiles, frogs and native plants in a range of major vegetation types (from heathland and sedgeland to woodland, forest and rainforest) and in response to fire, and weed and feral predator control. Importantly, the monitoring program has provided a foundational platform from which a suite of post-graduate studies and other research programs have been completed.

Further works undertaken. A key part of the researcher-manager partnership has been to analyse the long-term trajectories of populations of mammals, birds and reptiles in Booderee National Park. The monitoring data indicate that many species of mammals are declining, with some having become recently locally extinct (e.g. Greater Glider Petauroides volans) or close to extinction in the reserve (e.g. Common Ringtail Possum Pseudocheirus peregrinus) . This is despite populations of these species persisting in nearby reserves.  Robust interrogation of the multi-taxa monitoring data has been unable to identify reasons for these declines. Interestingly, the declines observed for mammals have not been observed to date in other vertebrate groups, including birds, reptiles and amphibians. An experimentally-based reintroduction program for the Greater Glider aims to not only re-establish populations of the species in Booderee National Park, but also to identify the reasons for the original decline. That program will be in addition to reintroduction programs already underway for other mammal species, the Long-nosed Potoroo (Potorous tridactylus), the Southern Brown Bandicoot (Isoodon obesulus) and Eastern Quoll (Dasyurus vivverinus) that used to inhabit Booderee National Park but which went extinct many decades earlier.

Additional research being undertaken in Booderee National Park has included: (1) studies of the effectiveness of control efforts for Bitou Bush and associated recovery of native vegetation and native fauna, (2) the interactive effects of fire and browsing on native plants and an array of animal groups, and (3) studies of leaf litter and other fuel dynamics in relation to previous fire history and macropod browsing.

Figure 1. Key area of Booderee National Park showing an area of coastal forest before and after Bitou Bush treatment.

Further results to date. Research and monitoring in the past six years have resulted in many new insights including some of considerable value for informing restoration programs. A small subset of these findings is outlined below.

  • Conventional approaches to the control of invasive Bitou Bush entail spraying ultra-low volume herbicide (Fig. 1), followed by burning of the “cured” dead material, and then respraying of the seedlings that germinate after fire. This spray-burn-spray protocol is both the most ecologically effective and the most cost-effective way of controlling Bitou Bush and, at the same time, facilitates the recovery of native vegetation. More recent analysis has revealed spray frequency as the most important determinant of long-term control. There are mixed effects of control methods on native species; plant species abundance was positively related to Bitou Bush control, while native bird abundance (except for Eastern Bristlebird Dasyornis brachypterus, Fig 2.) and mammal abundance were weakly negatively associated with Bitou control.
  • There can be strong interactions between the occurrence of fire and browsing by macropods on native plants as well as particular groups of animals such as spiders.
  • Reintroduction programs for the Southern Brown Bandicoot and Eastern Quoll have been relatively successful, although the latter species suffers high rates of mortality, particularly as a result of fox predation and collisions with motor vehicles. Nevertheless, populations of both species have survived over multiple years and reproduced successfully.

Figure 2. The Eastern Bristlebird, a species for which Booderee National Park is a stronghold. Notably, the species responds positively to management interventions to control Bitou Bush. (Photo Graeme Chapman)

Lessons learned and future directions. The work at Booderee National Park is a truly collaborative partnership between reserve managers, a university and the local Indigenous community.  A key part of the enduring, long-term success of the project has been that a full-time employee of The Australian National University has been stationed permanently in the Parks Australia office in the Jervis Bay Territory. That person (CM) works on an almost daily basis within Booderee National Park and this provides an ideal way to facilitate communication of new research and monitoring results to managers. It also enables emerging management concerns to be included as part of adaptive monitoring practices.

One of the key lessons learned from the long-term work has been the extent of ecological “surprises” – that is, highly unexpected results, including those which continue to remain unexplained. An example is the rapid loss of the Greater Glider and the major decline in populations of the Common Ringtail Possum. One of the clear benefits of this integrated monitoring-management team has been the rapid response to emerging threats. For example in response to high rates of mortality of reintroduced Eastern Quolls, control of the Red Fox was intensified within the park and greater cross-tenure control efforts with neighbouring private and public land managers have commenced. Regular evaluation of monitoring data and management actions has also enabled careful examination of the kinds of risks that can compromise reintroduction programs. These and other learnings will inform other, future reintroduction and translocation programs that are planned for Booderee National Park such as that for the Greater Glider.

Stakeholders and funding bodies. Ongoing work has been supported by many funding bodies and partners. These include the Wreck Bay Aboriginal Community who are the Traditional Owners of Booderee National Park as well as Parks Australia who co-manage the park with the Wreck Bay Aboriginal Community. Other key funders include the Department of Defence, the Thomas Foundation, The National Environmental Science Program (Threatened Species Recovery Hub), the Australian Research Council, the Margaret Middleton Foundation, and the Norman Wettenhall Foundation. Partnerships with Rewilding Australia, Taronga Conservation Society, WWF Australia, NSW Forestry Corporation and various wildlife sanctuaries have been instrumental to reintroduction programs.

Contact information. David Lindenmayer, Chris MacGregor, Natasha Robinson and Claire Foster are with the National Environmental Science Program (Threatened Species Recovery Hub), Fenner School of Environment and Society, The Australian National University (Canberra, ACT, 2601, david.lindenmayer@anu.edu.au). Nick Dexter is with Parks Australia, Jervis Bay Territory, Australia, 2540.

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Posted in Assisted regeneration, Coastal & marine, Community involvement, EMR 20th anniversary updates, Fauna & habitat, faunal reintroduction, Fire Ecology & Management, Indigenous land & sea management, Monitoring, Pest animal issues & solutions, Pest species, Rainforest, Reserve management, Restoration & management theory, Sclerophyll communities, Threatened species & communities, Uncategorized, Weed issues & solutions, Wetland

The Tiromoana Bush restoration project, Canterbury, New Zealand

Posted on 2 February 2019 by | Comments Off on The Tiromoana Bush restoration project, Canterbury, New Zealand

Key words: Lowland temperate forest, animal pest control, weed control, restoration plantings, public access, cultural values, farmland restoration

Introduction. Commencing in 2004, the 407 ha Tiromoana Bush restoration project arose as part of the mitigation for the establishment of the Canterbury Regional Landfill at Kate Valley, New Zealand. The site lies one hour’s drive north of Christchurch City in North Canterbury coastal hill country (Motunau Ecological District, 43° 06’ S, 172° 51’ E, 0 – 360 m a.s.l.) and is located on a former sheep and beef farm.

Soils are derived from tertiary limestones and mudstones and the site experiences an annual rainfall of 920mm, largely falling in winter. The current vegetation is a mix of Kānuka (Kunzea robusta) and mixed-species shrubland and low forest, restoration plantings, wetlands, Gorse (Ulex europaeus) and European Broom (Cytisus scoparius) shrubland and abandoned pasture. Historically the area would have been forest, which was likely cleared 500-700 years ago as a result of early Māori settlement fires. A total of 177 native vascular plant and 22 native bird species have been recorded, including four nationally threatened species and several regionally rare species.

Before and after photo pair (2005-2018). showing extensive infilling of native woody vegetation on hill slopes opposite, restoration plantings in the central valley, and successional change from small-leaved shrubs to canopy forming trees in the left foreground. (Photos David Norton.)

 

Project aims. The long-term vision for this project sees Tiromoana Bush, in 300 years, restored to a: “Predominantly forest ecosystem (including coastal broadleaved, mixed podocarp-broadleaved and black beech forests) where dynamic natural processes occur with minimal human intervention, where the plants and animals typical of the Motunau Ecological District persist without threat of extinction, and where people visit for recreation and to appreciate the restored natural environment.”

Thirty-five year outcomes have been identified that, if achieved, will indicate that restoration is proceeding towards the vision – these are:

  1. Vigorous regeneration is occurring within the existing areas of shrubland and forest sufficient to ensure that natural successional processes are leading towards the development of mature lowland forest.
  2. The existing Korimako (Bellbird Anthornis melanura) population has expanded and Kereru (Native Pigeon Hemiphaga novaeseelandiae) are now residing within the area, and the species richness and abundance of native water birds have been enhanced.
  3. The area of Black Beech (Fuscospora solandri) forest has increased with at least one additional Black Beech population established.
  4. Restoration plantings and natural regeneration have enhanced connectivity between existing forest patches.
  5. Restoration plantings have re-established locally rare vegetation types.
  6. The area is being actively used for recreational, educational and scientific purposes.

Day-to-day management is guided by a five-year management plan and annual work plans. The management plan provides an overview of the approach that is being taken to restoration, while annual work plans provide detail on the specific management actions that will be undertaken to implement the management plan.

Forest restoration plantings connecting two areas of regenerating Kānuka forest. Photo David Norton.

 

Restoration approach and outcomes to date. The main management actions taken and outcomes achieved have included:

  • An Open Space Covenant was gazetted on the title of the property in July 2006 through the QEII National Trust, providing in-perpetuity protection of the site irrespective of future ownership.
  • Browsing by cattle and sheep was excluded at the outset of the project through upgrading existing fences and construction of new fences. A 16 km deer fence has been built which together with intensive animal control work by ground-based hunters has eradicated Red Deer (Cervus elaphus) and helped reduce damage caused by feral pigs (Sus scrofa domesticus).
  • Strategic restoration plantings have been undertaken annually to increase the area of native woody and wetland vegetation, as well as providing food and nesting resources for native birds. A key focus of these has been on enhancing linkages between existing areas of regenerating forest and re-establishing rare ecosystem types (e.g. wetland and coastal forest).
  • Annual weed control is undertaken focusing on species that are likely to alter successional development (e.g. wilding conifers, mainly Pinus radiata, and willows Salix cinerea and fragilis) or that have the potential to smother native regeneration (e.g. Old Man’s Beard Clematis vitalba). Gorse and European Broom are not controlled as they act as a nurse for native forest regeneration and the cost and collateral damage associated with their control will outweigh biodiversity benefits.
  • Establishment of a public walking track was undertaken early in the project and in 2017/2018 this was enhanced and extended, with new interpretation included. Public access has been seen as a core component of the project from the outset so the public can enjoy the restoration project and access a section of the coastline that is otherwise relatively inaccessible.
  • Part of the walkway upgrade included working closely with the local Māori tribe, Ngāi Tūāhuriri, who have mana whenua (customary ownership) over the area. They were commissioned to produce a pou whenua (land marker) at the walkway’s coastal lookout. The carvings on the pou reflect cultural values and relate to the importance of the area to Ngāi Tūāhuriri and especially values associated with mahinga kai (the resources that come from the area).
  • Regular monitoring has included birds, vegetation and landscape, with additional one-off assessments of invertebrates and animal pests. Tiromoana Bush has been used as the basis for several undergraduate and postgraduate student research projects from the two local universities.
Vigorous regeneration of Mahoe under the Kānuka canopy following exclusion of grazing animals. Photo David Norton.

 

Lessons learned. Important lessons learned over the 15-years have both shaped the approach to management at this site and have implications for the management of other projects:

  • Control of browsing mammals, both domestic and feral, has been essential to the success of this project. While domestic livestock were excluded at the outset of the project, feral Red Deer and pigs have the potential to seriously compromise restoration outcomes and these species have required additional management inputs (fencing and culling).
  • Since removal of grazing, the dominant exotic pasture grasses, especially Cocksfoot (Dactylis gomerata), now form tall dense swards. These swards severely restrict the ability of native woody plants to establish and herbicide control is used both pre- and post-planting to overcome this. During dry summers (which are common) the grass sward is also a significant fuel source and the walkway is closed during periods of high fire risk to avoid accidental fires which would decimate the restoration project.
  • Regular monitoring is important for assessing the biodiversity response to management. Annual photo-monitoring now spanning 15-years is highlighting significant changes in land cover across the site, while more detailed monitoring of plants and birds is strongly informing management actions. For example, seven-years of bird monitoring has indicated an ongoing decline in some native birds that is most likely due to predation (by cats, mustelids, rodents, hedgehogs). As a result, a predator control programme is commencing in 2019.
  • Simply removing grazing pressure from areas of existing regenerating native woody vegetation cannot be expected to result in the return of the pre-human forest because of the absence of seed sources. Permanent plots suggest that Kānuka is likely to be replaced by Mahoe (Melicytus ramiflorus), with few other tree species present. Gap creation and enrichment planting is therefore being used to speed up the development of a more diverse podocarp-angiosperm forest canopy.
Kate Pond on the Tiromoana Bush walkway. The pond and surrounding wetland provides habitat for several native water birds. Photo Jo Stilwell.
The pou whenua on the coastal lookout platform looking north up the coastline. Photo David Norton.

 

Looking to the future. Considerable progress in restoring native biodiversity at Tiromoana Bush has been achieved over the last 15 years and it seems likely that the project will continue to move towards achieving its 35-year outcomes and eventually realising the long-term vision. To help guide management, the following goals have been proposed for the next ten-years and their achievement would further help guarantee the success of this project:

  • The main valley floor is dominated by regenerating Kahikatea (Dacrycarpus dacrydioides) forest and wetland, and the lower valley is dominated by regenerating coastal vegetation.
  • At least one locally extinct native bird species has been reintroduced.
  • Tiromoana Bush is managed as part of a wider Motunau conservation project.
  • The restoration project is used regularly as a key educational resource by local schools.
  • The walkway is regarded as an outstanding recreational experience and marketed by others as such.
  • Tiromoana Bush is highly valued by Ngāi Tūāhuriri.
Kereru, one of the native birds that restoration aims to help increase in abundance. Photo David Norton.

 

Stakeholders and funding. The project is funded by Transwaste Canterbury Ltd., a public-private partnership company who own the landfill and have been active in their public support for the restoration project and in promoting a broader conservation initiative in the wider area. Shareholders of the partnership company are Waste Management NZ Ltd, Christchurch City Council and Waimakariri, Hurunui, Selwyn and Ashburton District Councils.

Contact Information. Professor David Norton, Project Coordinator, School of Forestry, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand. Phone +64 (027) 201-7794. Email david.norton@canterbury.ac.nz

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Posted in agricultural lands, Assisted regeneration, Community involvement, Cultural & socio-economic issues & solutions, Education & communication, Fauna & habitat, Indigenous land & sea management, Landscape pattern & design, Monitoring, New Zealand, Podocarp forest, Reserve management, Threatened species & communities, Weed issues & solutions, Wetland

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Recovery of indigenous plants and animals in revegetated areas at ‘The Waterways’, Victoria.

Posted on 11 July 2018 by | Comments Off on Recovery of indigenous plants and animals in revegetated areas at ‘The Waterways’, Victoria.

Photo 1.  Aerial view of Waterways from the west

By Damien Cook

 Introduction. Waterways is a 48-hectare restoration project located on Mordialloc Creek in Melbourne’s south- eastern suburbs which combines a housing estate with large areas of restored habitat set aside for indigenous fauna and flora in open space, lakes and other wetlands (see Photo 1).

Prior to restoration the land at Waterways was a property used for grazing horses and supported pasture dominated by exotic species such as Reed Fescue (*Festuca arundinacea) and Toowoomba Canary Grass (*Phalaris aquatica). (Note that an Asterix preceding a scientific name denotes that the species is not indigenous to the local area).

The habitats which are being restored at “The Waterways” reflect those that originally occurred in the Carrum Carrum Swamp, a vast wetland complex which, prior to being extensively drained in the 1870s, stretched from Mordialloc to Kananook and as far inland as Keysborough.

Local reference ecosystems were selected to act as a benchmark for what was to be achieved in each restored habitat in terms of species diversity and cover. Habitat Hectare assessments have been used to monitor the quality of restored vegetation (see Appendix 1).

A total of nine Ecological Vegetation Classes (EVCs, the standard unit of vegetation mapping in Victoria) are being re-established across the site across the following habitats

  • Open water, Submerged Aquatic Herbfields and Exposed Mudflats
  • Densely vegetated marshes
  • Swamp Paperbark Shrubland
  • Tussock Grassland
  • Plains Grassy Woodland

Photo 2. This sequence of photographs, taken over a nine-month period at the Waterways, shows vegetation establishment in a constructed wetland from newly constructed and bare of native species on the left to well vegetated with a high cover of indigenous plants and minimal weeds on the right.

Works undertaken. Restoration of the site commenced in October 2000. Extensive weed control and earthworks were carried out prior to the commencement of revegetation works, which involved planting, by 2003, over 2 million local provenance, indigenous plants.  Grassland species were planted out of hikos at a density of 5 to 6 per square meter into areas that had been treated with both knock-down and pre-emergent herbicide. Ongoing management of the site has included ecological burning and follow up weed control. When started the Waterways was the largest and most complex ecological restoration project ever undertaken in Victoria.

Results

Plants

Open water, Submerged Aquatic Herbfields and Exposed Mudflats.  Deep, open water areas cover an area of about 30 hectares of the site. Vegetation growing in this habitat includes submerged herb-fields of Pondweeds (Potamogeton species), Eel Grass (Vallisneria australis) and Stoneworts (Chara and Nitella species), which were planted over summer 2000/01.

Densely vegetated marshes. This habitat occupies about 10 hectares of the site, occurring where water is less than 1.5 meters deep around the fringes of the lakes and as broad bands across the wetlands. Swards of large sedges including Tall Spike-rush (Eleocharis sphacelata), Jointed Twig-sedge (Baumea articulata), Leafy Twig-sedge (Cladium procerum) and River Club-rush (Schoenoplectus tabernaemontani); aquatic herb-fields of Water Ribbons (Cycnogeton procerum), Upright Water-milfoil (Myriophyllum crispatum) and Running Marsh-flower (Ornduffia reniformis); as well as meadows supporting rushes, sedges and amphibious herbs. Localized areas with high salinity (4000 to 12 000 ppm) have been planted with a halophytic (salt tolerant) community including Sea Rush (Juncus krausii), Australian Salt-grass (Distichlis distichophylla), and Shiny Swamp-mat (Selliera radicans). Planting began in the marshes at the Waterways in October 2000 and vegetation established very rapidly in most areas (see Photo 2). This vegetation type provides habitat for the locally vulnerable Woolly Water-lily (Philydrum lanuginosum).

Swamp Paperbark Shrubland covers about 8 hectares, consisting of a 1ha remnant and additional areas that were planted in spring/summer 2001. As this shrubland habitat matures it is forming a dense canopy of species including Swamp Paperbark (Melaleuca ericifolia), Prickly Moses (Acacia verticillata subsp. verticillata), Manuka (Leptospermum scoparium), Woolly Tea-tree (Leptospermum lanigerum), Tree Everlasting (Ozothamnus ferrugineus) and Golden Spray (Viminerea juncea).

Photo 3. Rare plant species that have been established in restored native grasslands at “Waterways” include Grey Billy-buttons (Craspedia canens), Matted Flax-lily (Dianella amoena) and Pale Swamp Everlasting (Coronidium gunnianum).

Tussock Grassland covers about four hectares at the Waterways between two major wetland areas. About a third of this habitat was planted in spring 2001, with the remainder in spring 2002. The dominant plants of this habitat are tussock-forming grasses including wallaby grasses (Rytidosperma species), Kangaroo Grass (Themeda triandra) and Common Tussock Grass (Poa labillardierei var. labillardierei). A diverse array of native wildflowers occurs amongst these grasses. Rare plant species that have been established in this habitat zone include Grey Billy-buttons (Craspedia canens), Matted Flax-lily (Dianella amoena) and Pale Swamp Everlasting (Coronidium gunnianum, see Photo 3).

Plains Grassy Woodland This habitat type occurs in mosaic with Tussock grassland and differs in that it supportsscattered trees and clumps of shrubs. River Red Gum (Eucalyptus camaldulensis subsp. camaldulensis) and Swamp Gum (Eucalyptus ovata var. ovata) have been planted so that they will eventually form an open woodland structure. Other tree and tall shrub species planted in this habitat include Drooping Sheoak (Allocasuarina verticillata), Blackwood (Acacia melanoxylon) and the tree form of Silver Banksia (Banksia marginata), which is now very uncommon in the local area.

Seasonal Wetlands Small seasonal wetlands occur within Tussock Grassland (see Photo 4). Rare plant species that have been established in this habitat zone include Swamp Billy-buttons (Craspedia paludicola), Woolly Water-lily (Philydrum lanuginosum), Grey Spike-rush (Eleocharis macbarronii), Giant River Buttercup (Ranunculus amplus) and the nationally endangered Swamp Everlasting (Xerochrysum palustre).


Photo 4. Seasonal rain-filled wetland at Waterways

 Animals.

The Waterways is home to 19 rare and threatened fauna species including the nationally endangered Australasian Bittern (Botaurus poiciloptilus), Glossy Grass Skink (Pseudemoia rawlinsoni) and Magpie Goose (Anseranas semipalmata). The successful establishment of diverse vegetation has so far attracted 102 species of native birds, and the wetlands on the site are home to seven species of frogs.

Open water areas support large populations of Black Swans (Cygnus atratus), Ducks (Anas species), Eurasian Coots (Fulica atra), Cormorants (Phalacrocorax and Microcarbo species), Australian Pelicans (Pelecanus conspicillatus) and Australasian Darters (Anhinga novaehollandiae) that either feed on fish and invertebrates or the foliage and fruits of water plants.  As water levels recede over summer areas of mudflat are exposed. These flats provide ideal resting areas for water birds as well as feeding habitat for migratory wading birds including the Sharp-tailed Sandpiper (Calidris acuminata), Red-necked Stint (Calidris ruficollis) and Common Greenshank (Tringa nebularia) that fly from their breeding grounds as far away as Alaska and Siberia to spend the summer in Australia and are protected under special treaties between the Governments of countries through which they travel.

Photo 5. Magpie Geese (Anseranas semipalmata) at Waterways

In 2007 a small group of Magpie Geese (Anseranas semipalmata) became regular visitors to The Waterways (see Photo 5). This species was once extremely abundant in the Carrum Carrum Swamp. However, it was driven to extinction in southern Australia in the early 1900s by hunting and habitat destruction. The Magpie Goose seems to be making a recovery in Victoria, with numbers building up from birds captured in the Northern Territory and released in South Australia that are spreading across to areas where the species formerly occurred.

Seasonal wetlands are important breeding areas for frogs including the Banjo Frog (Limnodynastes dumerilii), Striped Marsh Frog (Limnodynastes peroni) and Spotted Grass Frog (Limnodynastes tasmaniensis) and a range of invertebrates that do not occur in the larger, more permanent storm water treatment wetlands such as Shield Shrimp (Lepidurus apus viridus). Birds which utilize these wetlands for feeding include the White-faced Heron (Egretta novaehollandiae) and Latham’s Snipe (Gallinago hardwickii).

Restored grassland provides an ideal hunting ground for several birds of prey, including the Brown Falcon (Falco berigora), Black-shouldered Kite (Elanus axillaris) and Australian Kestrel (Falco cenchroides). It also provides cover and feeding habitat for insect and seed-eating birds such as the Brown Quail (Coturnix ypsilophora). A flock of about 20 Blue-winged Parrots (Neophema chrysostoma) have been regularly seen in this habitat. These parrots are usually quite uncommon in the Melbourne area. Moist grasslands beside the wetland have been colonised by the vulnerable Glossy Grass Skink (Pseudemoia rawlinsoni) (see Photo 6).

Densely vegetated marshes provide habitat for a diversity of small, secretive birds such as Ballion’s Crake (Porzana pusilla), Little Grassbird (Megalurus gramineus) and Australian Reed Warbler (Acrocephalus australis), which find suitable refuges in the cover provided by dense vegetation. Dense thickets of Swamp Paperbark shrublands provide cover and feeding habitat for Ring-tail Possums (Pseudocheris peregrinus) and bushland birds such the Eastern Yellow Robin (Eopsaltria australis), thornbills (Acanthiza species), Superb Fairy-wren (Malurus cyaneus) and Grey Fantail (Rhipidura albiscapa). As the grassy woodlands mature they are providing structural habitat diversity and accommodating woodland birds such as cuckoos (Cacomantis and Chalcites species) and pardalotes (Pardalotus species).

It will take many years for the River Red Gums to reach a majestic size and stature, and to provide tree hollows which are essential for many species of native fauna. A limited number of tree hollows are provided in the dead trees (stags) that were placed in the Waterways wetlands.

Photo 6. The vulnerable Glossy Grass Skink (Pseudemoia rawlinsoni) at Waterways

The Future. The habitats that have been created at the Waterways are about 18 years old, yet they have already attracted a vast array of native fauna. Waterways is now home to 14 rare and threatened plant species and 19 threatened animal species. There is incredible potential for the area to provide vitally important habitat for an even greater diversity of rare plants and animals as these habitats mature.

If the area is to reach its full potential careful management of weeds and pest animals is required. Ongoing monitoring of flora and fauna is also necessary. These are both areas in which the local community is becoming involved.

Acknowledgements. The high standard of restoration achieved on the Waterways project was due to the project being appropriately funded and because it was managed by ecologists experienced in planning and implementing ecological restoration.  The project was partly funded by Melbourne Water, who are now the managers of the site, and partly by a developer, the Haines Family.  This unique relationship and the generosity and willingness to try something innovative by the developer were important factors in the success of the project.

Contact: Damien Cook (rakali2@outlook.com.au)

Appendix 1. Habitat Hectare results for four quadrats at Waterways, 2006

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Posted in Assisted regeneration, Cultural & socio-economic issues & solutions, Fauna & habitat, Fire Ecology & Management, Freshwater aquatic, Grassland/grassy understorey, Planning, monitoring & assessment, reconstruction, Standards, Threatened species & communities, Urban ecosystems, Victoria, Wetland

A framework and toolbox for assessing and monitoring swamp condition and ecosystem health

Posted on 24 May 2016 by | Comments Off on A framework and toolbox for assessing and monitoring swamp condition and ecosystem health

Key words: Upland swamp, stygofauna, sedimentology, ecosystem processes, biological indicators, geomorphology

Introduction. Upland swamps are under increasing pressure from anthropogenic activities, including catchment urbanization, longwall mining, and recreational activities, all under the omnipresent influence of global climate change. The effective management of upland swamps, and the prioritisation of swamps for conservation and restoration requires a robust means of assessing ecosystem health. In this project we are developing a range of ecological and geomorphic indicators and benchmarks of condition specifically for THPSS. Based on a multi-metric approach to ecosystem health assessment, these multiple indicators and benchmarks will be integrated into an ultimate index that reflects the health of the swamp.

In this project we have adopted (and modified) the definition of ecosystem health applied to groundwater ecosystems by Korbel & Hose (2011). We define ecosystem health of a swamp as, i.e., “an expression of a swamp’s ability to sustain its ecological functioning (vigour and resilience) in accordance with its organisation while maintaining the provision of ecosystem goods and services”.

Design. Our approach to develop indicators of swamp health followed those used to develop multimetric indices of river and groundwater ecosystem health (e.g. Korbel & Hose 2011). We used the ‘reference condition’ approach in which a number of un- or minimally disturbed swamps were sampled and the variation in the metric or index then represents the range of acceptable conditions (Bailey et al. 1998; Brierley & Fryirs 2005).

We focused initially on swamps in the Blue Mountains area. Reference (nominally unimpacted) and test sites with various degrees and types of impacts were identified using the database developed by the concurrent THPSS mapping project (Fryirs and Hose, this volume).

Following our definition of ecosystem health, we selected a broad suite of indicators that reflect the ecosystem structure (biotic composition and geomorphic structure) and function, including those relating to ecosystem services such as microbially-mediated biogeochemical functions, geomorphic processes and hydrological function, as well as the presence of stressors, such as catchment changes. Piezometers and dataloggers have been installed in a number of swamps to provide continuous data on groundwater level fluctuations and sediment cores taken at the time of piezometer installation have provided detailed information on the sedimentary structure, function and condition of the swamps.

Results. Intact and channelised swamps represent two geomorphic condition states for THPSS. Not surprisingly, variables reflecting the degree of catchment disturbance (such as urbanization) were strongly correlated with degraded swamp condition. Variables related to the intrinsic properties of swamps had little relationship to their geomorphic condition (Fryirs et al. 2016). Intact and channelized swamps present with typically different sediment structures. There were significant differences in the texture and thickness of sedimentary layers, C: N ratios and gravimetric moisture content between intact swamps and channelised swamps (Friedman & Fryirs 2015). The presence and thickness of a layer of contemporary sand in almost all channelised swamps and its absence in almost all intact swamps is a distinctive structural difference.

Disturbed swamps have poorer water quality at their downstream end, and associated with this, lower rates of organic matter processing occurring within the streams (Hardwick unpublished PhD Data). Similarly, the richness and abundance of aquatic invertebrates living within swamp sediments (stygofauna) is poorer in heavily disturbed swamps than in undisturbed or minimally disturbed areas (Hose unpublished data).

Within the swamp sediments, important biogeochemical processes, such as denitrification and methanogenesis, are undertaken by bacteria. In this study we are measuring the abundance of the functional genes such as a surrogate for functional activity within the swamp sediments. There is large spatial variation in the abundance of functional genes even within a swamp, which complicates comparisons between swamps. Within our focus swamp, the location closest to large stormwater outlets had different functional gene abundances, in particular more methanogens, than in less disturbed areas of the swamp. There were greater abundances of denitrification genes, nirS and nosZ, in shallower depths despite denitrification being an anoxic process, which may reflect changes in the surficial sediments due to disturbance. Overall however, the abundance of functional genes seem to vary more with depth than with location, which means that comparisons between swamps must ensure consistency of depth when sampling sediments (Christiansen, unpublished PhD data).

The list of indicators currently being tested in this project and by others in this program (Table 1) will be refined and incorporated into the final assessment framework. Thresholds for these indicators will be determined based on the range of conditions observed at the reference sites. The overall site health metric will reflect the proportion of indicators which pass with respect to the defined threshold criteria. At this stage, the final metrics will be treated equally, but appropriate weightings of specific metrics within the final assessment will be explored through further stakeholder consultation.

Stakeholders and Funding bodies. This research has been undertaken as PhD research projects of Kirsten Cowley, Lorraine Hardwick and Nicole Christiansen at Macquarie University. The research was funded through the Temperate Highland Peat Swamps on Sandstone Research Program (THPSS Research Program). This Program was funded through an enforceable undertaking as per section 486A of the Environment Protection and Biodiversity Conservation Act 1999 between the Minister for the Environment, Springvale Coal Pty Ltd and Centennial Angus Place Pty Ltd.  Further information on the enforceable undertaking and the terms of the THPSS Research Program can be found at www.environment.gov.au/news/2011/10/21/centennial-coal-fund-145-million-research-program. This project was also partly funded by an ARC Linkage Grant (LP130100120) and a Macquarie University Research and Development Grant (MQRDG) awarded to A/Prof. Kirstie Fryirs and A/Prof. Grant Hose at Macquarie University. We also thank David Keith, Alan Lane, Michael Hensen, Marcus Schnell, Trevor Delves and Tim Green.

Contact information. A/Prof. Grant Hose, Department of Biological Sciences, Macquarie University (North Ryde, NSW 2109; +61298508367; grant.hose@mq.edu.au); and A/Prof. Kirstie Fryirs, Department of Environmental Sciences, Macquarie University (North Ryde, NSW 2109; +61298508367; kirstie.fryirs@mq.edu.au).

Table 1. List of indicators of swamp condition that are being trialled for inclusion in the swamp health assesment toolbox.

Functional indicators table

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Posted in Landscape pattern & design, Monitoring, New South Wales, Planning, monitoring & assessment, Research summary, Sydney Sandstone Swamps Forum 2016, Wetland