Introduce nurse plants to aid focal non-woody plants: brackish/saline wetlands

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

20%
Certainty

20%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Nurse plants, also known as companion plants or pioneer plants, can be planted alongside focal plants to help the focal plants establish (Padilla & Pugnaire 2006). Nurse plants may benefit focal plants in variety of ways, including: trapping and stabilizing sediments, trapping propagules, mitigating harsh environmental conditions (e.g. temperature fluctuations and strong sunlight), attracting pollinators, deflecting herbivory away from focal species, and/or limiting weed establishment.

Caution: Nurse plant species must be chosen carefully. Species that spread easily or are very strong competitors can cause more harm than good. For example, the non-native mangrove apple Sonneratia apetala has been used to restore Chinese mangroves, but has spread into neighbouring forests (Ren et al. 2009). Use of non-native nurse plants may not always be ethically acceptable.

To be summarized as evidence for this action, studies must have (a) deliberately introduced nurse plants before planting target marsh or swamp vegetation, and (b) reported the effects of the nurse plants on other vegetation, not just the survival or growth of the nurse plants. Studies must have explicitly planted vegetation for its nursing effect. Studies are not summarized as evidence here if they planted target vegetation into existing nurse vegetation (e.g. Egerova et al. 2003; McKee et al. 2007), or examined spontaneous colonization amongst planted nurse vegetation.

Related actions: Introduce nurse plants without introducing target marsh or swamp vegetation.

^{Egerova J., Proffitt C.E. & Travis S.E. (2003) Facilitation of survival and growth of Baccharis halimifolia L. by Spartina alterniflora Loisel. in a created Louisiana salt marsh. Wetlands, 23, 250–256.}

^{McKee K.L., Rooth J.E. & Feller I.C. (2007) Mangrove recruitment after forest disturbance is facilitated by herbaceous species in the Caribbean. Ecological Applications, 17, 1678–1693.}

^{Padilla F.M. & Pugnaire F.I. (2006) The role of nurse plants in the restoration of degraded environments. Frontiers in Ecology and the Environment, 4, 196–202.}

^{Ren H., Lu H., Shen W., Huang C., Guo Q., Li Z. & Jian S. (2009) Sonneratia apetala Buch.Ham in the mangrove ecosystems of China: an invasive species or restoration species? Ecological Engineering, 35, 1243–1248.}

Study locations

Key messages

One study evaluated the effects, on vegetation, of introducing nurse plants to brackish/saline wetlands planted with emergent, non-woody plants. The study was in the USA.

VEGETATION COMMUNITY

VEGETATION ABUNDANCE

VEGETATION STRUCTURE

OTHER

Germination/emergence (1 study): One replicated, controlled study in an estuary in the USA reported that planting nurse plants had no effect on germination of sown arrowgrass Triglochin concinna. No seedlings were found around nurse plants or on bare sediment.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated, controlled study in 2001 in an estuary in California, USA (Zedler 2003) reported that planting nurse plants before sowing seeds of arrowgrass Triglochin concinna had no effect on its germination. In the growing season after sowing, no arrowgrass seedlings were found – whether seeds were sown under nurse plants or onto bare sediment. The study suggests that high temperatures, high salinities and thick mats of microorganisms may have limited germination across the site. Methods: In March 2001, sets of 25 arrowgrass seeds were sown onto an area of recently reprofiled intertidal sediment. Of these, 288 sets were sown under planted adult nurse plants (alkali heath Frankenia salina, salt marsh daisy Jaumea carnosa or California sea lavender Limonium californicum; single plants or single-species clusters). A further 144 sets were sown onto bare sediment. All seeds sets were covered with burlap fabric after sowing. Any nurse plants that died were replaced. Seedlings were counted over the 2001 growing season.
Study and other actions tested
Referenced paper
Zedler J.B., Morzaria-Luna H. & Ward K. (2003) The challenge of restoring vegetation on tidal, hypersaline substrates. Plant and Soil, 253, 259-273.

Please cite as:

Taylor N.G., Grillas P., Smith R.K. & Sutherland W.J. (2021) Marsh and Swamp Conservation: Global Evidence for the Effects of Interventions to Conserve Marsh and Swamp Vegetation. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Use fences or barriers to protect brackish/saline wetlands planted with non-woody plants Action Link	No evidence found (no assessment)	0	Synopsis Link
Introduce nurse plants to aid focal non-woody plants: freshwater wetlands Action Link	Unknown effectiveness (limited evidence)	2	Synopsis Link
Add below-ground organic matter before/after planting trees/shrubs: freshwater wetlands Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link