Practise ‘wildlife gardening’

Overall effectiveness category Evidence not assessed
Number of studies: 4
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Background information and definitions

Within urban areas, public parks and private gardens represent a significant area of potential habitat. Wildlife-friendly gardening could include a number of independent actions for butterflies and moths, such as planting nectar-rich flowers or native plant species, reducing the frequency of weeding or cutting, and reducing chemical impacts, as well as actions aimed at other wildlife. This action includes studies where two or more of these are carried out together, as well as less frequently tested actions.

This action includes studies where non-native plants are used to provide nectar resources. For studies exclusively testing the planting of native species, see “Plant parks and gardens with appropriate native species”. See also “Alter mowing regimes on greenspaces and road verges”, “Pollution – Stop using herbicides on pavements and road verges” and “Pollution – Stop using pesticides as seed dressings and sprays in flower beds and greenspace”.

Study locations

Key messages

Four studies evaluated the effects of practising wildlife gardening on butterflies and moths. Two were in the UK and one was in each of France and the USA.

COMMUNITY RESPONSE (1 STUDY)

Richness/diversity (1 study): One replicated, paired, controlled study in the USAfound that areas with reduced frequency weeding had a similar species richness of adult butterflies compared to areas with conventional weeding.

POPULATION RESPONSE (3 STUDIES)

Abundance (3 studies): Two replicated studies (including one paired, controlled study) in the UK and the USA found that increasing the number and age of potted nettle plants in gardens and weeding less frequently did not increase abundance of butterflies, all caterpillars and caterpillars and eggs of four target species. One replicated, site comparison study in France found that gardens where insecticides and herbicides were not used and where there were natural features had a higher abundance of butterflies, but gardens where fungicides and snail pellets were not used had a lower abundance of butterflies.

BEHAVIOUR (2 STUDIES)

Use (2 studies): One replicated study in the UK reported that caterpillars only occasionally used potted nettle plants in gardens. One site comparison study in the UK found that planted buddleia and marjoram were visited by adult butterflies and moths more frequently than other plant species.

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 study in 2000–2002 in 20 urban gardens in Sheffield, UK (Gaston et al. 2005) reported that caterpillars were only occasionally found on potted nettle Urtica dioica plants, and that increasing the number of plants or the age of the plants did not increase the number of caterpillars found. In the three years of the experiment, comma caterpillars Polygonia c-album, (it is unclear whether these were adults or caterpillars) were found on potted nettle plants in one, eight and four of the gardens respectively. In June 2000 one tub of nettles was placed in each of 20 gardens. To encourage new growth half of the stems were cut at the first visit and all at the end of each autumn. To test whether patch size or age of plant affected caterpillar presence, in April 2002 five gardens had their plant replaced with a new plant, five had their original plant, five had their plant replaced with four new plants, and five had their original plant plus three new plants. During the summer and autumn of 2000, 2001 and 2002 nettles were checked for caterpillars and their presence (feeding damage and webs).
Study and other actions tested
Referenced paper
Gaston K.J., Smith R.M., Thompson K. & Warren P.H. (2005) Urban domestic gardens (II): experimental tests of methods for increasing biodiversity. Biodiversity and Conservation, 14, 395-413.
A replicated, site comparison study in 2009–2011 in 3,722 private gardens in France (Muratet & Fontaine 2015) found that there was a higher abundance of butterflies in gardens where insecticides and herbicides were not used and where there were more natural features, but a lower abundance of butterflies where fungicides and snail pellets were not used. There were significantly more butterflies in gardens that used no pesticides (average: 7) than those with insecticide (average: 6) and herbicide (average: 7) use, but fewer butterflies in gardens that did not use conventional (average: 7) or Bordeaux mixture (average: 7) fungicides or snail pellets (average: 7). There was no difference in abundance between gardens that did and did not use fertilizer. Additionally, there were more butterflies in gardens which had more “natural” features, such as fallow plots, nettles, ivy, brambles and dead trees (data presented as model results). Data was obtained from a citizen monitoring scheme across France. Monthly from March–October participants submitted information about their gardens, including the number of butterflies seen, the presence of fallow plots, nettles, ivy, brambles and dead trees, and whether they use chemicals in gardening.
Study and other actions tested
Referenced paper
Muratet A. & Fontaine B. (2015) Contrasting impacts of pesticides on butterflies and bumblebees in private gardens in France. Biological Conservation, 182, 148-154.
A site comparison study in 2013 in a rural garden in East Sussex, UK (Shackleton & Ratnieks 2016) found that of 11 planted flower varieties, buddleia Buddleia davidii and marjoram Origanum vulgare were visited most by butterflies and day-flying moths, and they attracted different groups of species. Marjoram received the most visits by butterflies (50% of all visits), followed by buddleia (22% of all visits), compared to 0–12% visits for the other nine flower varieties. Meadow brown Maniola jurtina (213 out of 287 visits) and gatekeeper Pyronia tithonus (908/961 visits) were most attracted to marjoram, and peacock Inachis io (312/328 visits), painted lady Vanessa cardui (123/143 visits) and red admiral Vanessa atalanta (9/10 visits) were most attracted to buddleia. However, hemp agrimony Eupatorium cannibinum attracted the highest diversity of butterfly species (data presented as model results). See paper for more details. Eleven varieties of ornamental flowers were grown in 1–5 discrete patches (total: 1–15 m²) around a garden. From 8–13th August 2013, butterflies and day-flying moths feeding on each patch were counted 105 times (three times/hour at 20-minute intervals) in good weather.
Study and other actions tested
Referenced paper
Shackleton K. & Ratnieks F.L.W. (2016) Garden varieties: How attractive are recommended garden plants to butterflies? Journal of Insect Conservation, 20, 141-148.
A replicated, paired, controlled study in 2013–2014 in a managed park in Georgia, USA (Majewska et al. 2018) found that areas with reduced weeding had a similar overall abundance and species richness of adult butterflies, and adults, eggs and caterpillars of four target species, compared to areas with regular weeding. The total abundance and species richness of butterflies was similar in plots weeded every two months and plots weeded every two weeks (data presented as model results). In addition, the abundance of adults, eggs and caterpillars of four target species (monarch Danaus plexippus, queen Danaus gilippus, gulf fritillary Agraulis vanillae, and black swallowtail Papilio polyxenes) were similar in plots with reduced weeding and plots with regular weeding (see paper for details). In spring 2013, four fenced, irrigated experimental plots (7.6 × 15.2 m, 20–88 m apart) were established in each of three blocks, 250 m apart. Each plot was planted with 128 plants of 13 species, and was surrounded by mown grass. Plots were assigned to four treatments/block: planting with native or non-native species, and low (every other month) or high (every other week) weed maintenance by hand pulling, trimming, and spot herbicide application. From May–September 2014, adult butterflies were surveyed for 7 minutes/plot, 1–4 times/month, and eggs and caterpillars of four species (monarch, queen, black swallowtail, gulf fritillary) were counted weekly or monthly on 2–14 host plants/butterfly species/plot.
Study and other actions tested
Referenced paper
Majewska A.A., Sims S., Wenger S.J., Davis A.K. & Altizer S. (2018) Do characteristics of pollinator-friendly gardens predict the diversity, abundance, and reproduction of butterflies? Insect Conservation and Diversity, 11, 370-382.

Please cite as:

Bladon A.J., Bladon, E. K., Smith R.K. & Sutherland W.J. (2023) Butterfly and Moth Conservation: Global Evidence for the Effects of Interventions for butterflies and moths. Conservation Evidence Series Synopsis. 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:

Butterfly and Moth Conservation

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