Plant/sow seeds of nurse plants alongside focal plants

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
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How is the evidence assessed?

Effectiveness

0%
Certainty

20%
Harms

10%

Calculating overall effectiveness category

Background information and definitions

Nurse plants are plants which are thought to aid the growth of other species by providing relatively benign conditions below their canopy. Examples of these altered conditions may include increases in moisture and nutrients, and decreases in temperature and damage from herbivores (de Toledo Castanho & Prado 2014). Combining the planting or sowing of seeds of nurse plants with that of focal plants may help to increase focal plant survival and growth.

de Toledo Castanho, C. and P. I. Prado (2014). "Benefit of shading by nurse plant does not change along a stress gradient in a coastal dune." PLOS ONE 9(8): e105082.

Study locations

Key messages

A randomized, replicated, controlled study in the UK found that sowing seeds of nurse plants and heathland plants did not increase the cover of common heather. One replicated, randomized, controlled study in the USA found that sowing seeds of nurse plants and California sagebrush seeds together reduced survival of shrubs in more than half of cases. The same study found that California sagebrush biomass was also reduced when its seeds were sown with those of nurse plants.

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, randomized, controlled study in 1993–1994 in former shrubland in California, USA (Marquez & Allen 1996) found that sowing California sagebrush Artemisia californica seeds with the seeds of nurse plants reduced its survival in four of seven comparisons and reduced its biomass in seven of seven comparisons. In four of seven comparisons, California sagebrush seedlings showed lower survival where they were sown with seeds of nurse plants (5–75% survival) than when they were sown without seeds of nurse plants (100% survival). In seven of seven comparisons California sagebrush biomass was lower when sown with seeds of nurse plants (0-1 g/m²) than when sown without seeds of nurse plants (5 g/m²). In three 0.75 m² plots California sagebrush seeds were sown, while in 18 plots a mixture of California sagebrush and succulent lupine Lupinus succulentus or rose clover Trifolium hirtum seeds were sown. Plant survival was recorded in May 1994 following which all plants were harvested and dried to calculate their biomass.
Study and other actions tested
Referenced paper
Marquez V.J. & Allen E.B. (1996) Ineffectiveness of two annual legumes as nurse plants for establishment of Artemisia californica in coastal sage scrub. Restoration Ecology, 4, 42-50.
A randomized, replicated, controlled study in 1994–2003 in two agricultural fields in Suffolk, UK (Walker et al. 2007) found that sowing seeds of a nurse plant, followed by seeds of heathland species did not increase the cover of common heather Calluna vulgaris . After nine years, cover of common heather in areas where seeds of a nurse plant and heathland species were sown (0%) was not significantly different to that in areas where no seeds had been sown (0%). In 1994 seeds of the nurse plant Italian ryegrass Lolium multiflorum were sown, followed in 1995 by seeds of common heather, grasses, and herbs in four 80 m² plots. In four other plots no seeds were sown. In April 2003 five 2500 cm² quadrats were placed in each plot and the cover of all plant species was recorded.
Study and other actions tested
Referenced paper
Walker K.J., Warman E.A., Bhogal A., Cross R.B., Pywell R.F., Meek B.R., Chambers B.J. & Pakeman R. (2007) Recreation of lowland heathland on ex-arable land: assessing the limiting processes on two sites with contrasting soil fertility and pH. Journal of Applied Ecology, 44, 573-582.

Please cite as:

Martin, P.A., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Shrubland and Heathland Conservation. Pages 483-525 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

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This Action forms part of the Action Synopsis:

Shrubland and Heathland Conservation

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