Action: Add root-associated fungi to plants (before planting)
- Three studies examined the effect of adding root-associated fungi to planted peatland vegetation. All three studies involved peat swamp tree seedlings: two in the wild and one in a nursery.
- Survival (2 studies): Two controlled studies (one also replicated, paired, before-and-after) in peat swamps in Indonesia found that adding root fungi did not affect survival of planted red balau or jelutong in all or most cases. However, one fungal treatment increased red balau survival in one study.
- Growth (3 studies): Two replicated, controlled, before-and-after studies (one also paired) of peat swamp trees in Indonesia found that adding root fungi to seedlings had no effect on growth: for red balau and jelutong or the majority of 15 tested species. However, one controlled study in Indonesia found that adding root fungi increased growth of red balau seedlings.
Many plants (including grasses, trees and shrubs) form mutually beneficial associations with fungi. The ‘mycorrhizal’ fungi live in or around plant roots. They can increase plant access to nutrients and minimise the effect of stresses such as drought and pollution (Finlay 2008). Adding these fungi to plants before they are introduced to peatlands could therefore help survival and growth. Fungi could be added via a root dip, or through adding spores to soil in the nursery.
Related interventions: other interventions to protect or prepare plants.
Finlay R.D. (2008) Ecological aspects of mycorrhizal symbiosis: with special emphasis on the functional diversity of interactions involving the extraradical mycelium. Journal of Experimental Botany, 59, 1115–1126.
Supporting evidence from individual studies
A controlled study in 2002–2006 in a logged peat swamp in Kalimantan, Indonesia (Turjaman et al. 2011) found that inoculating red balau Shorea balangeran seedlings with root fungi increased growth (for three of three fungal species) but did not affect survival (for two of three fungal species). Forty months after planting, inoculated seedlings were taller than uninoculated seedlings (213–240 cm vs 206 cm) and had wider stems (diameter 30–37 cm vs 27 cm). Only seedlings inoculated with Strobilomyces sp. fungi had higher survival (85%) than uninoculated seedlings (83%). Survival of seedlings inoculated with two other fugal species was 79–81%. In November 2002, 400 red balau seedlings were planted into logged forest: 100 inoculated with each fungal species and 100 uninoculated. Seedlings had been grown in sterilized peat in a nursery and inoculated with wild-collected spores suspended in water. Seedling height, stem diameter and survival were measured 40 months after planting.
A replicated, paired, controlled, before-and-after study in 2007–2009 in a peat swamp forest in Indonesia (Graham et al. 2013) found that inoculation with root fungi had no effect on survival or growth of two planted tree species: red balau Shorea balangeran and jelutong Dyera polyphylla. One year after planting, seedlings with and without added root fungi had similar survival (75–91%; data not reported separately for forest types), similar height increase (in five of five forest types; with fungi: 2–11 cm; without fungi: 3–10 cm) and similar diameter increase (in five of five forest types; with fungi: 0.6–2.7 mm; without fungi: 0.7–2.4 mm). In 2007 or 2008, nursery-reared seedlings (800 red balau and 700 jelutong) were planted in five forest types from natural/closed forest to degraded/open land. Approximately two thirds of these seedlings had been inoculated with fungi by adding spore tablets to the soil in the nursery. The other seedlings were not inoculated. After one year, seedling survival and growth were measured.
A replicated, controlled, before-and-after study in 2011 in a nursery in Indonesia (Yuwati et al. 2014) found that inoculation with root fungi typically had no effect on growth of peat swamp tree seedlings. Seedlings of 15 species were studied. Seedlings with and without added root fungi showed similar height growth for 14–15 species (depending on the fungus used) and similar stem diameter growth for 11–14 species. In June 2011, thirty seedlings of each tree species were inoculated with root fungi (10 seedlings for each of three fungal species). Ten additional seedlings were not inoculated. Seedlings were planted in pots of sterilized peat, having been grown from sterilized seed or transplanted from the wild. The duration of the experiment was not reported.
- Turjaman M., Santoso E., Susanto A., Gaman S., Limin S.H., Tamai Y., Osaki M. & Tawaraya K. (2011) Ectomycorrhizal fungi promote growth of Shorea balangeran in degraded peat swamp forests. Wetlands Ecology and Management, 19, 331-339
- Graham L.L.B., Turjaman M. & Page S.E. (2013) Shorea balangeran and Dyera polyphylla (syn. Dyera lowii) as tropical peat swamp forest restoration transplant species: effects of mycorrhizae and level of disturbance. Wetlands Ecology and Management, 21, 307-321
- Yuwati T.W., Graham L.L.B., Rachmanadi D., Santosa P.B. & Rusmana . (2014) Response of peat swamp forest species to mycorrhizal inoculations. Pages 64-76 in: F.R.U. Banjarbu, . FORDA & L.L.B. Graham (eds.) Tropical Peat Swamp Forest Silviculture in Central Kalimantan. Kalimantan Forests and Climate Partnership, Indonesia.