Category Archives: Restoration & management theory

From Rainforest to Oil Palms and back again: a Daintree Rainforest Rescue in far north Queensland

Robert Kooyman, Joe Reichl, Edie Beitzel, Grant Binns, Jennifer Croes, Erryn Stephens, and Madeleine Faught

The establishment of Oil Palm (Elaeis guineensis) plantations is responsible for massive rainforest clearing and destruction throughout the tropics of Southeast Asia and beyond, and has captured the attention of conservation organisations around the world. One such organisation is Rainforest Rescue (RR), a not for profit Australian based conservation NGO. Through local and international projects (including in the Daintree region of Australia and Sumatra in Indonesia) RR has undertaken conservation actions that include removal of Oil Palm plantations to re-establish rainforest close to National Park areas.

The rainforest of the Daintree region provides an active window into the evolution, biogeography, and ecology of the southern (Gondwanan) rainforests, and their interaction with Indo-Malesian floristic elements. It has many (ca. 120) federal- and state- listed Threatened, Vulnerable, Of Concern, and Rare plant and animal species and a range of rainforest types.

To achieve restoration of a small (27.6 ha) but important piece of the global distribution of lowland tropical rainforest, RR purchased Lot 46 Cape Tribulation Road in the Daintree area of far north Queensland, Australia in 2010 and, in 2012, secured funding to set the property on its long journey back to rainforest.

The property was partly cleared in the 1960s, first for cattle grazing and later for Oil Palm cultivation. It has a mix of cleared (ca. 11 ha) and early stage natural regeneration (ca. 10ha) areas, bounded on two sides by more intact and mature rainforest (ca. 7 ha). Soils are mostly free-draining sandy clay loams on flat terrain

The on-ground works.  The property was divided into five working Zones as part of the restoration planning process (Fig. 1). Because of a nearby large seed source forest a key objective of the project is to maximise and protect natural regeneration, as well as planting larger openings. Up to 30,000 trees representing 100 species are expected to be planted during the 2-year life of the project, with around 10 ha of natural regeneration interspersed.

Figure 1. Map showing property, work zones (ZONE 1-5), permanent photographic points (Photo point 1-9), location of planting trials (Zones 1 and 2), and primary weed control area (2013) in orange. (Courtesy Google Earth)

Figure 1. Map showing property, work zones (ZONE 1-5), permanent photographic points (Photo point 1-9), location of planting trials (Zones 1 and 2), and primary weed control area (2013) in orange. (Courtesy Google Earth)

Trial tree plantings were undertaken in early 2011 and 2012, and selective weed management (herbicide based grass and soft weed control) began at the same time to optimise natural regeneration prior to identifying and preparing suitable planting sites.

Plantings.  The planting trials were each one hectare in area and designed to test the efficacy of two different high diversity (60-90 species) planting designs. In Zone 1 tree spacing was 2.5m, and in Zone 2 the spacing was 1.5m. Seedlings for rainforest plantings were propagated and grown in the RR nursery in the Daintree lowlands. Seed collection was undertaken north of the Daintree River and included seed collected from the property. A low number of vines were included in the species mix for subsequent plantings.

A total of 90 species have been planted to date. The species mix included some early stage (pioneer type) tree species from genera such as Polyscias (Araliaceae), Alphitonia (Rhamnaceae), Macaranga (Euphorbiaceae) and Commersonia (Malvaceae); and tall fast growing species such as Elaeocarpus grandis (Elaeocarpaceae) and Aleurites moluccana (Euphorbiaceae). The remaining species represented mostly moderately fast growing species, and some slower growing mature phase rainforest species.

Weed control. Where possible, large Oil Palms were removed mechanically, but to protect existing rainforest regeneration many required stem injection with herbicide. Several methods are currently being trialled to determine the most time and cost effective approach to controlling this large and difficult weed.

Late in 2012 and early in 2013 extensive mechanical and chemical weed control was undertaken in Zones 3, 4 and 5 (Fig. 1). This included mechanical clearing of large areas dominated by Giant Bramble (Rubus alceifolius) and other weeds, and some mechanical removal of Oil Palm seedlings on the southern side of the creek that traverses the property (Zones 3 and 4). Follow up chemical control (systematic backpack spraying of glyphosate) was conducted immediately (as required) to complete the site preparation for planting. This was targeted at grasses, broad-leaf weeds, and regrowth of woody weeds.

Monitoring design. Monitoring plots (7 / 50 x 20m plots, each with 10 / 10 x 10m subplots) and permanent photographic points (12 in total, 7 in association with monitoring plots) were established in the five working Zones. Cover, number of species and density will be recorded in these plots at each stratum at 12 month intervals. One monitoring plot was established in each of Zones 1 and 2, three in Zone 3 (including directly adjacent to Zone 4), and two in Zone 5 (in the north of the property; yet to be measured). Zone 4 will be monitored visually and by photo point as it is mostly natural regeneration enhanced by weed control.

Preliminary Results. The first round of project monitoring (year 1 establishment) provided base-line information for future development of the plantings and natural regeneration through assessing canopy cover, leaf litter cover, and a range of other factors that will change over time (Table 1). Informal observations have shown that site dominance was achieved by the trees planted 12 and 18 months ago in Zones 1 and 2.  Substantial numbers of wildling seedlings (of up to 11 species in a plot; and 15 in total) were found in the sites monitored prior to more recent planting.

Mechanical weed control was reported to be extremely effective and the operator was able to minimise damage to existing regrowth of species such as Melicope elleryana (Rutaceae), Glochidion harveyanum var. harveyanum (Phyllanthaceae), Macaranga involucrata var. mallotoides (Euphorbiaceae), Polyscias australiana (Araliaceae), Rhodamnia sessiliflora (Myrtaceae), Alphitonia incana (Rhamnaceae) and Aidia racemosa (Rubiaceae). In combination with the early implementation of broad and targeted spraying this maximised the retention of substantial existing saplings and seedlings.

Project funding will cease in 2014, and control of all weeds and rainforest establishment is expected to be completed in 2015; with only minor weed control required thereafter once canopy cover is established. Monitoring will continue at 12 month intervals and inform future publications.

Acknowledgements: The project is dependent on the generous support of RR donors and the on-going efforts of RR staff in FNQld. Funding for the project was provided by a Federal Government Biodiversity Fund Grant.

Contact:  Robert Kooyman, National Herbarium of NSW, Royal Botanic Gardens and Domain Trust, Mrs Macquaries Road, Sydney 2000 Australia.   Email: robert@ecodingo.com.au;

Figure 2 Mechanical weed control in Zone 3 (January 2013) prior to planting. Note remaining natural regeneration.

Figure 2 Mechanical weed control in Zone 3 (January 2013) prior to planting. Note remaining natural regeneration.

Figure 3. Newly planted trees in Zone 3 (March 2013). Note surrounding natural regeneration.

Figure 3. Newly planted trees in Zone 3 (March 2013). Note surrounding natural regeneration.

Figure 4. Zone 2 planting trial established in late 2011 at 18 months. Tree spacing at 2 - 2.5m.

Figure 4. Zone 2 planting trial established in late 2011 at 18 months. Tree spacing at 2 – 2.5m.

Table 1.  Synthesis of baseline data for natural regeneration, and progress (including planting) up to February 2013 measured on (50 x 20m) permanent monitoring plots (PP), in Zones (1,2,3), by Themes (1 – planting; 2 – natural regeneration). PD – total planted diversity on plot; PS(n) – number of seedling planted on plot; WS – wildling seedlings (0.5-1m in height); WD – wildling diversity; Av. CC(%) – Average Canopy Cover (%); Av. L(%) – Average Litter Cover (%); Av. LBC(%) – Average Log-Branch Cover (%); Av. PCHt – Average planted canopy height (m); dbh – diameter at breast height (1.3m); NR – Number of stems, natural regeneration >1cm DBH; NR-div – Diversity of natural regeneration >1cm DBH; Age (mths) – Age of planting in months. Zone 4 (not shown) has permanent photo points and visual monitoring.

PP Zone Theme PD PS(n) WS WD Av.CC(%) Av.L(%) Av.LBC(%) Av. PCHt NR NR-div Age(m)

1

3

1, 2

82

424

236

7

27.5

52

7

0.6 – 1

218

12

1

2

3

1, 2

0

0

587

11

41

61.5

6.7

NA

248

11

0

3

3

1, 2

0

0

133

5

18.5

48.8

4.6

NA

109

9

0

4

2

1

85

390

45

7

13

30.6

3

1-2m

45

5

12

5

1

1

85

207

95

5

45.5

58

5

2-3m

48

7

18

Appendix 1 List of main weed species located and treated on the property.

Common Name Species Family Life Form
Sanchezia Sanchezia parvibracteata Acanthaceae herb
Brillantaisia Brillantaisia lamium Acanthaceae herb
Goosefoot Syngonium podophyllum Araceae vine
Toothed Philodendron Philodendron lacerum Araceae climber
Oil Palm Elaeis guineensis Arecaceae palm
Dracaeana Dracaeana fragans Asparagaceae small tree
Sensitive Plant Mimosa pudica Fabaceae creeper
Calopo Calopogonium mucunoides Fabaceae creeper
 Green Summer Grass Urochloa decumbens Poaceae grass
Giant Bramble Rubus alceifolius Rosaceae scrambler
Snake Weed Stachytarpheta cayennensis Verbenaceae herb

Restoration of Tuart (Eucalyptus gomphocephala) during prescribed burning in southwestern Australia

Katinka Ruthrof, Leonie Valentine and Kate Brown

Key words:  fire, regeneration, coarse woody debris, ashbed

Regeneration of Tuart (Eucalyptus gomphocephala), in many parts of its fragmented distribution in Western Australia, is nominal. Previous work has shown it has specific regeneration niche requirements, recruiting in ashbeds within canopy gaps. We conducted a field trial to determine whether regeneration could be facilitated by creating coarse woody debris (CWD) piles that would become ashbeds during a low-intensity, prescribed burn.

Regeneration experiment. Paganoni Swamp Bushland, a peri-urban Eucalyptus-Banksia woodland, was due for prescribed burning in 2011. Prior to the burn, twelve canopy gaps within the bushland were chosen to have CWD piles built up in the centre (5mx5m wide, 0.5m height). Six gaps were chosen to have no ashbeds, and so had any naturally occurring CDW removed. Adjacent to each plot (whether ashbed or no ashbed), an extra 5mx5m plot was marked out as a control.

The six gaps without ashbeds, and half of the 12 ashbeds, were broadcast with Tuart seed in plots of 5m x 5m following the prescribed burn.  Approximately 375 seeds/per 25m2 plot (after typical forestry seeding practice) were sown within one month of the prescribed burn.

The temperature of the control burn that moved through the area was measured in the gaps using pyrocrayons. These temperature-sensitive crayons were used to draw lines onto ceramic tiles. Five tiles were placed into each gap, either on the surface in the non-ashbed plots, or beneath the CWD piles, totaling 90 tiles.

Results. The majority of CDW piles burnt during the prescribed burning activities.  These piles burnt at high temperatures (~560Co) compared with the control plots (~70 Co). After six months, the ashbeds, especially those that were seeded, contained a significantly higher number of seedlings (0.7/m2 ± 0.3) than ashbeds without added seed (0.01/m2 ± 0.01) or control plots (0.0-0.05/m2 ± 0.0-0.05).

Lessons learned. Tuart regeneration can be facilitated at an operational scale as part of prescribed fire activities, through creation of CWD piles and broadcast seeding. However, higher rates of seeding could be used. Raking the seeds following broadcasting to reduce removal by seed predators may also increase seedling numbers.

Acknowledgements. Thanks go to the  State Centre of Excellence for Climate Change, Woodland and Forest Health, Murdoch University; Western Australian Department of Environment and Conservation; and to Friends of Paganoni Swamp.

Contact: Katinka Ruthrof, Research Associate, Murdoch University, South Street, Murdoch, 6150, Western Australia; Tel: (61-8) 9360 2605; Email: k.ruthrof@murdoch.edu.au

A created coarse woody debris pile within a canopy gap, ready for the prescribed burn

A created coarse woody debris pile within a canopy gap, ready for the prescribed burn

A created ashbed following the prescribed burn

A created ashbed following the prescribed burn

Pyrocrayon markings on - a tile showing the temperature of the prescribed burn

Pyrocrayon markings on – a tile showing the temperature of the prescribed burn

Tuart seedlings recruiting following ashbed creation and broadcast seeding. Note that this is the same ashbed as in Figure 2.

Tuart seedlings recruiting following ashbed creation and broadcast seeding. Note that this is the same ashbed as in Figure 2.

The Ridgefield Multiple Ecosystem Services Experiment: restoring and sustaining function in degraded ecosystems

Key words: carbon sequestration, invasion resistance, nutrient cycling, novel ecosystems, intervention ecology

Mike Perring

Introduction. Multiple, simultaneous, and rapid environmental changes make sustaining and restoring ecosystem functions an increasingly important but challenging task. The Ridgefield Multiple Ecosystem Services Experiment, being undertaken at the University of Western Australia’s Future Farm in the Western Australian wheat belt, tests the application of current ideas in ecology to ecological restoration, and seeks insights into how management interventions can sustain and restore multiple ecosystem functions in an era of rapid environmental change.

Design. Our experiment tests how different woody plant species mixtures affect provision of ecosystem functions and services, including carbon storage, nutrient cycling, invasion resistance, biodiversity maintenance, and prevention of soil erosion. We also consider potential tradeoffs in the provision of ecosystem functions, how different plant species mixtures may respond to simultaneous environmental changes, and how different plant species assemblages may affect other trophic levels, both above and below ground.

Experimental treatments, across 124 23x11m rip line plots, comprise native tree and shrub species, and span a diversity gradient from bare and single-species to mixtures of eight species. Species belong to four different functional groups based on differing nutrient acquisition strategies and morphologies. Plant assemblage treatments are replicated across former grazing and cropped landscapes.

The Ridgefield experimental site with formerly cropped area to the right and grazed blocks in middle and left (December 2010)

In addition to the role of species composition in determining ecosystem functions and services, we will examine the effect of simultaneous environmental changes (nitrogen deposition and weed invasion) on our chosen functions and services, particularly since the presence of exotics creates potentially novel ecosystem states. Our experiment will allow us to understand more about how combinations of plant species, and their associated traits, can be utilized to intervene and manage ecosystems to ensure capacity for ongoing function and service provision in the Anthropocene. In terms of theory, we are also interested in whether the provision of multiple ecosystem functions requires greater biodiversity than provision of single services, if there are tradeoffs among services as diversity levels increase, and how the traits of included species affect functioning.

York gum only plot (January 2011)

Participants and potential for collaboration. Participants include: Mike Perring, Kris Hulvey, Rachel Standish, Lori Lach, Tim Morald, Rebecca Parsons and Richard Hobbs. The study provides a platform for the investigation of a wide variety of ecologically and socially important questions, and we encourage interested parties to contact us should they wish to collaborate or conduct trials at the site.

Contact: Mike Perring, School of Plant Biology, University of Western Australia; Tel: +61 (0)8 6488 4692; Email: michael.perring@uwa.edu.au