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REVEGETATION

Pacific Islands face natural landscape modification because of population explosion, urbanisation and development activities such as tourism and recreation. Manmade disturbances such as vegetation removal; occur alongImage removed. the coast and rivers. Some of the reasons for removing riparian vegetation are for housing development, grazing by livestock, encouraging agriculture near streams and competition with non-native species. Once vegetation has been removed, coastal zones, beaches and riverbanks often begin to erode.

 

 

 

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Vegetative cover plays a key role in soil retention. To help keep soil in place and prevent soil loss from beaches or riparian zones, vegetation with deep roots, including native plants and woody perennials such as trees and  shrubs, can be planted. Enhancing revegetation with native vegetation can help in stabilising beaches and riverbanks, therefore reducing erosion and the impacts of storm surges. 

 

 

 

 

 

 

 

 

 

 

 

 

  • Revegetation is inexpensive and can be adapted to traditional knowledge on native plants and horticulture.
  • Increasing vegetative cover on beaches and riverfronts provides an important habitat for aquatic and terrestrial animals (including migratory birds).
  • Vegetation protects riverbanks from erosion, traps sediments and acts as biofilter against chemical residues.
  • A appropriately vegetated beach filters pollution from inland and helps to keep nearby reefs healthy and productive.
  • Revegetation using native species can also provide food, fibre and medicinal and cultural resources for local communities.
  • During the establishment phase, restored vegetation can easily impacted by natural (e.g. flooding) or manmade processes (e.g. grazing).
Indicative cost

Revegetation is relatively low to implement. Whilst providing cost estimates is difficult given the broad range of influencing factors across the Pacific, the below table outlines the key components that should be taken into account when estimating a revegetation project budget for a specific location.

Components

Unit
(A)

Number of units (B)

Unit Cost
(C)

Budget
(B x C)

Establishment Cost

        
  • Land (if not already held)

e.g. km2

      
  • Planning and design including community outreach

e.g. hours

      
  • Materials (e.g. seeds, plants, fencing)

e.g number

      
  • Labour

e.g. hours

      
  • Reporting to donor (if required)

e.g. hours

      

Ongoing Cost

        
  • Maintenance Cost (materials and labour)

e.g. number and hours

      
  • Reporting and Monitoring

e.g. hours

      

Revegetation is compared against hard infrastructure to protect coastal shorelines like seawalls and groynes and concreting riverbanks. Seawalls, groynes and concreting riverbanks are engineered structures designed to prevent erosion. Comparisons between the approaches include:

  • Hard infrastructure solutions are often more expensive.
  • The cost of maintenance and repairs of hard infrastructure is much higher than maintaining vegetation.
  • Hard infrastructure can cause negative environmental impacts, such as erosion to adjacent coastlines.
On-ground impacts that the EbA option addresses
Decreasing species composition
Increasing sediment loads in rivers
Inundation of coastal zones and riverbanks
Erosion of habitat and decreasing water quality

Case study

Coastal Revegetation for sustainable Future

Choiseul Province, Solomon Islands

Solomon Island’s Choiseul Province suffers from storm surges, changes in weather patterns and coastal erosion. The project Coastal Revegetation for Sustainable Future project aimed to use natural adaptation methods to address climate change in Choiseul Province. The project undertook village level vulnerability and adaptation analysis to align climate change adaptation strategies with the needs of the village and government. Funded by USAID, the project was coordinated by SPREP in collaboration with GIZ, the Nature Conservancy, Lauru Land Conference of Tribal Communities (LLCTC) and the Choiseul Provincial Government.

The activities performed as part of the project were:

  • Ecological assessment of the island and identification of coastal erosion sites.
  • Establishment of nursery to provide seedlings.
  • Mapping of three coastal revegetation sites.
  • Coastal revegetation as well as enhancement continued through plant transplantation to revegetation sites.

The project’s revegetation approach helped to protect soil from erosion; promote healthy rivers through ensuring a clean water supply; create healthy reefs through ensuring healthy coastal water; and sustain fish populations.

Reference: Ecosystem Based Adaptation to Climate Change in Solomon Islands. See https://www.sprep.org/news/ecosystem-based-adaptation-climate-change-solomon-islands and Half yearly report to USAID, https://www.sprep.org/attachments/bem/PEBACC/SPREP_USAID_REPORT_Solomon_Islands_September_2015_Final.pdf