Tonga – Land-Based Pollution

Coastal Reforestation in Tonga to Protect Agricultural Areas and Coastlines

Houma, southwest Tongatapu Island, Kingdom of Tonga

The Challenge
In large areas of Tonga, most of the original forest cover has been removed for timber, firewood or agricultural expansion. Tongan farmers traditionally protected coastal forests as a buffer between their farms and the sea to reduce salt spray, saltwater intrusion, and wind damage from storms and cyclones. However, during the past 25 to 50 years, these forests have been cleared to extend farms seaward and take valuable timber. The deforestation has exposed shorelines, accelerated coastal erosion, reduced suitable timber for construction and firewood, and resulted in the loss of medicinal, handicraft, and other useful plants.

Case Study Tonga Reforestation 2

The project site was Houma (southwest Tongatapu): a rocky, uplifted windward limestone area, with a raised limestone terrace and a fringing coral reef that drops off to the deep ocean. © Randy Thaman

This was particularly serious around Houma on the southwest coast of Tongatapu, the largest and most populated island in Tonga, where farms and grasslands expanded towards the coast, and traditional agroforestry trees were removed. Cattle, horses and especially pigs, and the indiscriminate use of fire to prepare gardens have also damaged these forests. These losses have resulted in drastic declines in agricultural productivity and associated biodiversity; some farms have been abandoned due to the increased wind and salt spray.

The coastal lands of many other small island states are seriously threatened by coastal erosion and increasing salination, which are exacerbated by rising sea levels. The erosion can be particularly serious if the natural coastal vegetation has been removed, which leads to seawater contamination and increasing wind damage to coconut plantations, food gardens and particularly, to freshwater wells. Accelerated erosion also damages nearby coral reefs.

Actions Taken
The Tonga Coastal Protection and Reforestation Project was implemented by the Ministry of Agriculture and Forestry (MAF) and partners in the mid-1990s to address these problems. The primary objectives were to: develop and implement an effective model for coastal reforestation near the Blow Holes at Houma, and develop effective community-based programs to promote coastal reforestation and protection at community and landowner levels.

As a first step, the MAF assessed many indigenous coastal species to find the best local trees and shrubs to plant along the coastal zone. They examined previous propagation projects looking for salt- and wind-tolerant plants, particularly important food and timber trees, or other trees with cultural significance such as those that are used medicinally or for woodcarving. Some of the species selected and used include: Casuarina equisetifolia which is successful as a windbreak, coconut palms, Pandanus tectorius, Hibiscus tiliaceus, Excoecaria agallocha, Calophyllum inophyllum, Hernandia nymphaeifolia, Terminalia catappa, Tournefortia argentea, Barringtonia asiatica, and Neisosperma oppositifolium. Other indigenous species that show promise for enrichment include the high-value carving wood and multi-purpose trees, Thespesia populnea, Cordia subcordata, Guettarda speciosa, Xylocarpus moluccensis, and sandalwood (Santalum yasi), which have all been historically selectively removed from Tonga’s coastal forests.

The project site was then marked out and manually cleared to remove Guinea grass (Panicum maximum) and other shrubby vegetation in order to reduce wild fires, which damaged previous re-vegetation projects in Tonga. A 5 m wide firebreak was cleared along the land side and planted with cassava (manioke) and other crops to keep out the Guinea grasses and prevent people from trampling or driving over the young trees.

Case Study Tonga Reforestation 3

View of plants double row Casuarina windbreak on inner margin of the reforestation area forest. © Randy Thaman

A three-phase approach was used for reforestation: First, fast-growing pioneer species were planted to provide shade and shelter from the wind, with Casuarinas planted in two staggered rows five meters apart on the land adjacent to farms. Large numbers of Casuarinas can be grown easily from seed; they fix nitrogen, are useful as firewood and grow rapidly to form effective wind breaks. Thirty different native coastal tree species were also planted on the seaward side of the Casuarinas. Secondly, after about 6 months, less-tolerant, but preferred species were planted in the shelter of the pioneers. Finally, they focused on hard-to-propagate species to increase diversity matching that of the original forest.

A concerted awareness-raising program on coastal reforestation was also implemented with the local community. The program focused on the need for maintenance of the newly planted trees. This included: frequent weeding to prevent overgrowth by grasses, shrubs and vines and to reduce the fuel for wildfires and the maintenance of firebreaks; the protection of pre-existing mature trees within the planted area; and control of free-ranging livestock, particularly pigs, cattle and horses.

Understory forest. Photo: Randy Thaman.

Understory forest. © Randy Thaman

How Successful Has it Been?
The coastal reforestation project in Houma was very successful in re-establishing a viable forest and windbreak. By 2011, the forest was fully grown with the double row of Casuarinas forming a wall along the coast and protecting the farms and many other coastal trees in this multi-species forest.

  • About 25,000 seedlings and saplings from 30 indigenous species were planted along 2 km of coastline in 2.4 hectares, mostly in a narrow band 12 m wide.
  • Approximately 80% had survived after 2 years, which was more than had been expected and a credit to community-based management of the project.
  • Cyclone Hina in March 1997 caused no damage to trees, except snapping off the upper crown of some Casuarinas.
  • The community played a very positive and critical role in the project through preparing, planting, and maintaining the site.

A limiting factor for reforestation on Tonga is the legal definition of the coastal area, “the area between high tide and 50 feet (15.4 m) inland,” but local boundary markers can vary considerably. This is virtually the only land owned and controlled by the Government; thus part of the Houma site was within the coastal zone, and the rest within the estate of village chiefs. No reforestation land was in farmers’ allotments, but the coastal forests were considered to be common property for firewood, medicinal plants, wood for carving and building. Thus the agreement from the community and chiefs to the tree planting project and allowing the forest to grow was and remains a critical factor to project success.

This project has shown that coastal reforestation is a very feasible and practical activity for communities to protect their land from sea-level rise, climate variability, and extreme events (such as tsunamis and cyclones).

Lessons Learned and Recommendations
Lessons learned and key recommendations include:

  • Coastal forest protection should be a high priority for small island communities, particularly with the threat of sea level rise and increasing extreme events. Protecting original coastal forests is easier and more cost-effective than re-establishing a degraded forest
  • Using local salt-tolerant species is a cost-effective, low-tech method for coastal reforestation to protect coastal lands and communities from natural disasters and sea-level rise, and to increase food production and promote livelihood security
  • Involving traditional leadership and identifying a ‘champion’ to raise awareness in communities for a project can enhance success. The project was proposed by the traditional chief from Houma (who was also the Prime Minister) which greatly increased stakeholder buy-in to the effort from the beginning
  • National legislation is needed to support community projects in the coastal commons to reduce  coastal forest degradation, shoreline erosion, reduce sedimentation on reefs and to protect threatened marine and land animals, such as sea turtles, sea birds and land crabs, for which coastal littoral forests are their main habitat
  • Before starting, it is essential to understand traditional ownership rights and customary (‘usufruct’) rights to resources on common land
  • Planting cassava and other food crops in the fire break was successful because people were able to use their labor to reduce the fire threat through weeding while at the same time growing valuable crops
  • Selecting the most appropriate multipurpose trees is important to gain community support, this project used over 30 indigenous species all of which are culturally valuable in Tonga
  • Coastal reforestation is a long-term effort. It is critical when designing a coastal reforestation project to provide enough time to allow a three-phase coastal reforestation (pioneer species, non-pioneer species, and high forest biodiversity enrichment planting). Short-term projects often fail, which results in a lack of confidence and support from local communities
  • Regular maintenance is essential to prevent grasses, weeds and smothering vines, and to reduce the amount of fuel for fires. This was done by the Forestry staff who were assisted by the Houma community
  • Protection from free-ranging livestock is essential and may require fencing
  • Coastal reforestation is a very practical activity for communities to protect their land from sea-level rise, climate variability and extreme events (such as tsunamis, cyclones and excessively high tides and waves
  • Protecting original multi-species coastal forests is easier and more cost-effective than re-establishing or enriching a degraded forest

Funding Summary
Secretariat of the Pacific Regional Environmental Program – $10,000 (US)

Lead Organizations
Tonga Ministry of Agriculture, Fisheries and Forestry

Randy Thaman, University of the South Pacific, Fiji;
Andrew Smith, WWF, Australia;
Tevita Faka’oso, Forestry division, Kingdom of Tonga;

Australia Aid (AusAid)
Secretariat of the Pacific Regional Environmental Program (SPREP)
The University of the South Pacific
The Nature Conservancy
The Houma local community

This case study was written by Randy Thaman, Andrew Smith, and Tevita Faka’osi, Case Study #22 from the following publication: Wilkinson, C., Brodie, J. (2011). Catchment Management and Coral Reef Conservation: A Practical Guide for coastal Resource Managers to Reduce Damage from Catchment Areas Based on Best Practice Case Studies (pdf). Global Coral Reef Monitoring Network and Reef and Rainforest Research Centre Townsville, Australia, 120 P.


Share on FacebookTweet about this on TwitterEmail this to someone

Australia – Monitoring Reef Resilience

Using Resilience Assessments to Inform the Design of Marine Protected Areas in Australia

Keppel Bay Reefs and Islands, Southern Great Barrier Reef, Australia

A bleached landscape from the severe bleaching event in the Keppel Bay in early 2006. © Great Barrier Reef Marine Park Authority

A bleached landscape from the severe bleaching event in the Keppel Bay in early 2006. © Great Barrier Reef Marine Park Authority

The Challenge
The Keppel Islands are a group of 16 continental islands lying 18 km off the coastal town of Yeppoon, in the southern Great Barrier Reef. Located in the shallow basin to the north of Keppel Bay, the islands are host to a patchwork of fringing reefs in various forms of development. Coral communities are abundant in some locations, with coral cover as high as 70%. Additionally, some of these reefs are dominated by extensive stands of branching Acropora that extend into shallow water.

Reefs within the Keppel Bay area have been affected by a devastating series of climate-related events over the last 25 years. Particularly severe flooding events occurred in 1991 and again in 2010. Both of these events devastated shallow reefs in the area. The mass bleaching events of 1998 and 2002 also impacted local reefs, and in the summer of 2006, most sites experienced at least 30% bleaching-induced mortality of corals due to a highly localized and severe warming event. Furthermore, during the latter half of 2006 an extremely low tide coincided with a heavy rainfall event killing many of the reef-flat corals throughout the reefs of the Keppel Bay. During summer 2009-2010, flooding led to a localized coral bleaching event. The flooding that began in 2010 extended through to May 2011 as a result of the record rainfall in the watershed. This most recent flooding caused 40-100% mortality of corals on the mostly fringing reefs, due to prolonged exposure to the freshwater flood plumes.

Many of the reefs within the Keppel Bay area are characterized by mono-specific stands of branching Acropora. The photo highlights that many of the corals at these sites compete for light and space with the macroalgae Lobophora variegata. Photo © Great Barrier Reef Marine Park Authority

Many of the reefs within the Keppel Bay area are characterized by mono-specific stands of branching Acropora. The photo highlights that many of the corals at these sites compete for light and space with the macroalgae Lobophora variegata. © Great Barrier Reef Marine Park Authority

Increasing development and the impact of climate change threaten the ability of the reefs to recover from these disturbances. The broad objective and vision of the Great Barrier Reef Marine Park Authority (GBRMPA) is to provide for the protection, wise use, understanding and enjoyment of the Great Barrier Reef in perpetuity, through the care and development of the Great Barrier Reef Marine Park. This will involve implementing both routine and reactive strategies to mitigate stressors that interact with those of climate change, in an effort to build resilience of the reef to future threats.

The Keppel Islands and surrounding waters are popular with a range of users. Historically, tourism has mainly focused around Great Keppel Island, and camping is available on seven other islands. The Great Barrier Reef Marine Authority and the Queensland Parks and Wildlife Service (QPWS) jointly manage the area. Many of the islands are also National Parks, and together with the Marine Park form part of the Great Barrier Reef World Heritage Area. Although there is increasing residential development along the mainland coast, there is also increasing participation in community groups, including the Capricorn Coast Local Marine Advisory Committee (LMAC), that have interests in the management of local environmental issues.

Actions Taken
Resilience is a central goal in the management of the Great Barrier Reef Marine Park, and specific resilience-building activities have been part of the management response from the earliest stages of planning and consultation. The Climate Change Group at the GBRMPA developed a resilience assessment and monitoring protocol in late 2007 that was applied to 31 sites within the Keppel Bay region. The initial focus was to test and refine a method for assessing the resilience of reef sites, as a basis for implementing spatial management tools (such as no-anchoring zones). The preliminary resilience assessment involved an identification of reef sites important to local users and assessed them against a suite of broad-scale and local-scale putative resilience indicators derived from preliminary resilience measuring protocols developed by The Nature Conservancy, IUCN Working Group on Climate Change and Coral Reefs, and the GBRMPA. The results of the resilience assessment were integrated into a numerical score that was used to rank sites on the basis of likely resilience to climate change.

Based on the outcomes of the resilience assessment, a ‘Resilience assessment and capacity building’ workshop involving the GBRMPA, QPWS, Traditional Owners, the LMAC, and local stakeholders was held in 2008. This workshop identified candidate sites for the installation of voluntary no-anchoring zones as a mechanism to restrict anchor damage (and hence increase resilience) due to the increase in recreational use of the Keppel Bay region. In late 2008, 16 no-anchoring buoys were installed by QPWS staff at four sites in the Keppel Bay region.

Broad-scale conservation initiatives implemented in recent years have been aimed at restoring and maintaining system resilience. Some initiatives in place in the Keppel Islands include:

  • A comprehensive network of marine protected areas in the area.
  • The Reef Water Quality Protection Plan, which includes an extensive Reef Water Quality Monitoring Program, works with farmers to reduce amounts of fertilizers and sediments entering reef waters.
  • Voluntary moratorium (at some locations) on commercial collection of some aquarium fish species, identified through risk assessments as potentially vulnerable to the combined impacts of disturbance (bleaching and flooding) and fishing. This moratorium was lifted in 2013 in response to signs that corals in key collecting areas had returned to a stable condition.
  • There is generally low take of herbivorous species by recreational and commercial fishers throughout the Great Barrier Reef, which helps to protect the ability of reef areas like the Keppels to recover after damage.

Community engagement is also a key aspect of this resilience-based management initiative. Local reef users are an important source of knowledge on patterns of use, resource condition and dynamics. Also, effective restoration of ecosystem resilience requires active and willing participation of reef users in efforts to reduce local stressors. Finally, meaningful engagement by the local community in development and implementation of resilience-based management actions also help ensure that social and economic impacts are minimized.

A coral-covered reef crest at Sloping Island. Photo © Great Barrier Reef Marine Park Authority

A coral-covered reef crest at Sloping Island. © Great Barrier Reef Marine Park Authority

How successful has it been?
Follow-up monitoring assessments in 2010, 2011, and 2012 revealed that the no-anchoring areas appear to be having a positive influence on coral health. Surveys indicate reduced anchor damage inside all four no-anchoring areas from ~80 instances per 1000 m2 in 2008 to high levels of voluntary compliance with the no-anchoring areas.

MPA network success
A 2010 report on the Reef Water Quality Protection Plan found that progress towards water quality targets was good, but that positive impacts on the marine environment are expected to take longer to manifest. There was a reduction in sediment and nutrient discharge in the Fitzroy watershed, which is the source of floodwaters for the Keppel Bay area.

The local community has become more aware of the vulnerability of the reefs in the area due to involvement in the resilience surveys and participation in the process of identifying sites for no-anchoring areas. This has resulted in a general increase in stewardship in the region, as evidenced by increased compliance with the voluntary no-anchoring areas, and strong willingness to assist researchers working in the area. Building on the knowledge about reef conditions and resilience concepts, the local community has developed organized and well-informed campaigns in response to development proposals in the area.

Lessons Learned and Recommendations
Lessons learned and some key recommendations include:

  • Resilience is a relative concept. For example, a site within one reef region having ‘high’ resilience, may have only ‘low’ or ‘medium’ resilience when compared to sites within other regions, and vice versa. This suggests that absolute values such as high and low should be used with caution. A relative approach (higher or lower), applied within a defined context, is likely to be more meaningful in most situations. In general, GRBMPA now ensures that the spatial context for any resilience assessments is clearly defined and communicated.
  • Quality standards for monitoring protocols should be developed, to reduce biases introduced by differing perspectives and expertise, therefore improving the use of these data for management decisions. The experience from the Keppels has provided the foundation for subsequent initiatives to formalize protocols for assessing system resilience. This includes a project in the Caribbean to develop a rapid resilience assessment protocol (monitoring multi-tool) for coral reef managers.
  • The Keppel Bay project first brought to light the value in using a simple, semi-quantitative approach to assessing resilience, using local and scientific expertise to estimate values for resilience indicator variables. Although coarse, this approach provides sufficient resolution for prioritizing management actions. Subsequent work has helped identify a more manageable set of resilience indicators, and the project in the Caribbean to develop a rapid resilience assessment protocol is designed around use of community members and local knowledge.
  • Community engagement at every step of the process was highly beneficial and as such, the no-anchoring zones appear to be having a positive influence on reef health despite being voluntary and non-enforceable.

Funding Summary
Department of Environment and Heritage Program
Queensland Department of National Parks, Recreation, Sport and Racing

Lead Organizations
Great Barrier Reef Marine Park Authority

Australian Institute of Marine Science
James Cook University
University of Queensland
Central Queensland University
Department of National Parks, Recreation, Sport, and Racing
Pro-vision Reef Inc.

Biophysical Assessment of the Reefs of Keppel Bay: A Baseline Study April 2007, Climate Change Group, GBRMPA (pdf)

Keppel Bay Case Study, GBRMPA (pdf)

Zoning map of the Capricorn section of the Great Barrier Reef Marine Park (pdf)

Share on FacebookTweet about this on TwitterEmail this to someone

Heeding a Call to Action—US Coral Reefs: The Untapped Potential of the Clean Water Act

This editorial, by the US Environmental Protection Agency, calls attention to the Clean Water Act (CWA), which can provide an opportunity to incorporate scientific knowledge into the management of coral reefs in for US waters. While MPAs are the dominant approach to coral reef protection, there is recognition that areas outside of MPAs must be monitored, protected, and restored. The authors propose that the CWA can be used for this purpose. The CWA provides a mandate to “restore and maintain the physical, chemical, and biological integrity of the Nation’s waters”, which includes all territorial seas within three miles of land (Secs.101 and 502). Although often perceived and interpreted as only a tool to address end-of-pipe contaminants, the CWA provides a regulatory framework that can potentially support protection of coral reefs. The key to engage the CWA to protect coastal resources, as indicated by the authors, is to formally document what is known about the condition and incorporate the knowledge into regulatory and reporting processes.

Author: Fore, L.S., J.R. Karr, W.S. Fisher, P. Bradley, and W.S. Davis
Year: 2009
View Full Article

Marine Pollution Bulletin 58(10): 1421-1423. doi: 10.1016/j.marpolbul.2009.06.00

Share on FacebookTweet about this on TwitterEmail this to someone

Are U.S. Coral Reefs on the Slippery Slope to Slime?

This article has received significant attention from researchers, managers, and the public. It is a bit controversial and the doom and gloom picture presented may or may not most accurately describe the current state of affairs. Regardless, the paper draws attention to issues of coral reef decline as part of Science’s Policy Forum. The author’s vision of how to reverse coral reef decline in the United States requires addressing multiple threats at the same time. Numerous responses to this paper are available in the 17 June 2005 Science issue (Volume 308).

Author: Pandolfi, J. M., J.B.C. Jackson, N. Baron, R.H. Bradbury, H.M. Guzman, T.P. Hughes, C.V. Kappel, F. Micheli, J.C. Ogden, H.P. Possingham, and E. Sala
Year: 2005
View Full Article

Science 307: 1725-1726. doi: 10.1126/science.1104258

Share on FacebookTweet about this on TwitterEmail this to someone

Relating Landscape Development Intensity to Coral Reef Condition in the Watersheds of St. Croix, US Virgin Islands

This study relates coral reef condition to human modifications of the landscape. Stony coral community richness, cover, colony size, and density were assessed along with 3-dimensional coral cover in St. Croix, US Virgin Islands, in 2006 and 2007. Land use/land cover data (LULC) and a landscape development intensity (LDI) index, an indicator of human activity calculated from the LULC data, were used to explore relationships with coral indicators. Human activity, measured by the LDI index, was negatively correlated with various indicators of coral condition, including taxa richness, colony size, and colony density. The LDI index is an effective landscape indicator of human impact on St. Croix corals, highlighting the link between land-based human activity and marine ecosystems.

The finding of a negative correlation between the watershed LDI index and coral condition indicators is consistent with expectations that higher human land-use activity adversely affects coral condition. The strength and significance of the relationships from this exploratory examination reveal a strong potential for this approach to demonstrate the cumulative effect of human watershed stressors on coral reef ecosystems.

Author: Oliver, L.M., J.C. Lehrter, and W.S. Fisher
Year: 2011
View Full Article

Marine Ecology Progress Series 427: 293-302. doi:10.3354/meps09087

Share on FacebookTweet about this on TwitterEmail this to someone

Coral Reefs Under Rapid Climate Change and Ocean Acidification

Levels of atmospheric CO2 continues to rise and threaten coral reefs globally. This is because atmospheric CO2 reacts with water in the ocean to produce carbonic acid which in turn forms bicarbonate ions that react with carbonate ions to produce more bicarbonate ions (reducing availability of carbonate in the ocean). Declines in available carbonate can reduce the calcification of coral reefs and marine organisms. The authors describe the consequences of increased atmospheric CO2 and subsequent warming, as predicted. Even under the best case scenario, ocean acidification will likely cause contractions of carbonate coral reefs if CO2 levels exceed 500 ppm. Although these global threats require changes at a global scale, local factors such as poor water quality, coastal pollution, and overexploitation of certain organisms, should be reduced to lesson the overall stressors to coral reef communities. The authors also suggest that healthy grazing populations should help to improve a coral reefs ability to bounce back from future disturbances; thus, healthy herbivore populations should be managed for explicitly.

Author: Hoegh-Guldberg, O.,  P.J. Mumby, A.J. Hooten, R.S. Steneck, P. Greenfield, E. Gomez, C.D. Harvell, P.F. Sale, A.J. Edwards, K. Caldeira, N. Knowlton, C.M. Eakin, R. Iglesias-Prieto, N. Muthiga, R.H. Bradbury, A. Dubi, and M.E. Hatziolos
Year: 2007
View Abstract
Email for the full article:

Science 318(5857): 1737-1742. doi: 10.1126/science.1152509

Share on FacebookTweet about this on TwitterEmail this to someone