Study

Growth performance of planted mangroves in the Philippines: revisiting forest management strategies

  • Published source details Samson M.S. & Rollon R.N. (2008) Growth performance of planted mangroves in the Philippines: revisiting forest management strategies. Ambio, 37, 234-240

Actions

This study is summarised as evidence for the following.

Action Category

Introduce tree/shrub seeds or propagules: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation

Introduce tree/shrub seeds or propagules: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation

Directly plant trees/shrubs: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation

Directly plant trees/shrubs: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation
  1. Introduce tree/shrub seeds or propagules: brackish/saline wetlands

    A study of mangrove planting projects in the Philippines (Samson & Rollon 2008) reported <5% survival of planted mangrove propagules/seedlings, but growth of surviving seedlings. Plantings almost exclusively involved Rhizophora spp. In two sites where survival was quantified, <5% of planted individuals survived (over nine months in one site; timescale not reported for other site). The study suggests that seedlings were killed by mechanical stress, substrate erosion, and oysters growing on their stems. Growth of surviving seedlings was quantified in eight sites. “Young individuals” grew by 3–13 cm over approximately 40 days (equivalent to 30–75 cm/year). Growth rates significantly differed between elevations: lowest in the low intertidal zone, and highest in the upper intertidal zone. Methods: The study reported results from various mangrove planting projects initiated since the 1980s: both afforestation (planting in mudflats, sandflats or seagrass beds) and reforestation (re-planting cleared mangroves, mostly fishponds). Propagules and/or seedlings were generally planted 1 m apart, following national guidelines, but often with 2–5 individuals at each planting spot.

    (Summarised by: Nigel Taylor)

  2. Introduce tree/shrub seeds or propagules: brackish/saline wetlands

    A replicated, paired, site comparison study of six coastal sites in the Philippines (Samson & Rollon 2008) reported that planted mangrove forests typically contained a higher density of trees and greater canopy cover than natural mangrove forests. Statistical significance was not assessed. After “several years”, planted forests contained a greater density of trees than natural forests in 9 of 10 comparisons (for which planted: 27–93 trees/100 m2; natural: 22–42 trees/100 m2). Planted forests had greater canopy cover than natural forests in 5 of 9 comparisons (data reported as a canopy index; other comparisons lower in planted forests). Methods: The study surveyed planted and natural mangrove forests at six sites (1–22 plots/forest type/site; dates not reported). Plantings had taken place since the 1980s (precise dates not reported) and almost exclusively involved Rhizophora spp. propagules and/or seedlings. These were generally planted 1 m apart, following national guidelines, but often with 2–5 individuals at each planting spot. Some plantings involved afforestation (planting in mudflats, sandflats or seagrass beds) and some involved reforestation (re-planting cleared mangroves, mostly fishponds).

    (Summarised by: Nigel Taylor)

  3. Directly plant trees/shrubs: brackish/saline wetlands

    A study of mangrove planting projects in the Philippines (Samson & Rollon 2008) reported <5% survival of planted mangrove seedlings/propagules, but growth of surviving seedlings. Plantings almost exclusively involved Rhizophora spp. In two sites where survival was quantified, <5% of planted individuals survived (over nine months in one site; timescale not reported for other site). The study suggests that seedlings were killed by mechanical stress, substrate erosion, and oysters growing on their stems. Growth of surviving seedlings was quantified in eight sites. “Young individuals” grew by 3–13 cm over approximately 40 days (equivalent to 30–75 cm/year). Growth rates significantly differed between elevations: lowest in the low intertidal zone, and highest in the upper intertidal zone. Methods: The study reported results from various mangrove planting projects initiated since the 1980s: both afforestation (planting in mudflats, sandflats or seagrass beds) and reforestation (re-planting cleared mangroves, mostly fishponds). Seedlings and/or propagules were generally planted 1 m apart, following national guidelines, but often with 2–5 individuals at each planting spot.

    (Summarised by: Nigel Taylor)

  4. Directly plant trees/shrubs: brackish/saline wetlands

    A replicated, paired, site comparison study of six coastal sites in the Philippines (Samson & Rollon 2008) reported that planted mangrove forests typically contained a higher density of trees and greater canopy cover than natural mangrove forests. Statistical significance was not assessed. After “several years”, planted forests contained a greater density of trees than natural forests in 9 of 10 comparisons (for which planted: 27–93 trees/100 m2; natural: 22–42 trees/100 m2). Planted forests had greater canopy cover than natural forests in 5 of 9 comparisons (data reported as a canopy index; other comparisons lower in planted forests). Methods: The study surveyed planted and natural mangrove forests at six sites (1–22 plots/forest type/site; dates not reported). Plantings had taken place since the 1980s (precise dates not reported) and almost exclusively involved Rhizophora spp. seedlings and/or propagules. These were generally planted 1 m apart, following national guidelines, but often with 2–5 individuals at each planting spot. Some plantings involved afforestation (planting in mudflats, sandflats or seagrass beds) and some involved reforestation (re-planting cleared mangroves, mostly fishponds).

    (Summarised by: Nigel Taylor)

Output references

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust