Restore or create habitat connectivity

Overall effectiveness category Awaiting assessment
Number of studies: 3
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How is the evidence assessed?

Effectiveness

not assessed
Certainty

not assessed
Harms

not assessed

Calculating overall effectiveness category

Background information and definitions

An important threat to butterflies and moths is the increasing fragmentation of habitat patches by human activity (Cavanzón-Medrano et al. 2018). This limits dispersal, especially in species which are poor fliers, and leaves isolated populations vulnerable to local extinction (van Langevelde & Wynhoff 2009). Species richness tends to be higher in better connected habitat patches (Öckinger et al. 2010), so restoring habitat connectivity across a landscape may be important for reconnecting isolated populations (Schultz et al. 2008). For example, woodland creation projects can be used to increase connectivity between existing woodland fragments, but are most beneficial when they are spatially-targeted (Fuentes-Montemayor et al. 2015).

For studies on retaining habitat corridors, see “Habitat protection – Retain connectivity between habitat patches”.

_{Cavanzón-Medrano L.E., Machkour-M’Rabet S., Chablé-Iuit L.R., Pozo C., Hénaut Y. & Legal L. (2018) Effect of Climatic Conditions and Land Cover on Genetic Structure and Diversity of Eunica tatila (Lepidoptera) in the Yucatan Peninsula, Mexico. Diversity, 10, 79.}

_{Fuentes-Montemayor E., Peredo-Alvarez V.M., Watts K. & Park K.J. (2015) Are woodland creation schemes providing suitable resources for biodiversity? Woodland moths as a case study. Biodiversity and Conservation, 24, 3049–3070.}

_{Öckinger E., Schweiger O., Crist T.O., Debinski D.M., Krauss J., Kuussaari M., Petersen J.D., Pöyry J., Settele J., Summerville K.S. & Bommarco R. (2010) Life-history traits predict species responses to habitat area and isolation: a cross-continental synthesis. Ecology Letters, 13, 969–979.}

_{Schultz C.B., Russell C. & Wynn L. (2008) Restoration, reintroduction, and captive propagation for at-risk butterflies: A review of British and American conservation efforts. Israel Journal of Ecology & Evolution, 54, 41–61.}

_{van Langevelde F. & Wynhoff I. (2009) What limits the spread of two congeneric butterfly species after their reintroduction: quality or spatial arrangement of habitat? Animal Conservation, 12, 540–548.}

Study locations

Key messages

Three studies evaluated the effects on butterflies and moths of restoring or creating habitat connectivity. Two studies were in the USA and one was in Sweden.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (2 STUDIES)

Abundance (2 studies): Two studies (including one controlled, before-and-after study) in the USA found that restoring connectivity between lupine or prairie patches increased the abundance of Karner blue and regal fritillary.

BEHAVIOUR (1 STUDY)

Use (1 study): One site comparison study in Sweden reported that grassland strips providing nectar or shelter were each more likely to be used by one of four butterfly species than strips with no resources.

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 controlled, before-and-after study in 1998–2001 in two pine plantations in Wisconsin, USA (Kleintjes et al. 2003) found that connecting patches of lupine Lupinus perennis by felling trees increased the abundance of Karner blue butterfly Lycaeides melissa samuelis. Two–three years after felling began, the peak abundance of Karner blue butterflies (26–49 individuals/year) was higher than before felling (32 individuals/year). On an unmanaged site, the peak abundance was lower two–three years after felling at the managed site (16–20 individuals/year) than before felling (46 individuals/year). Within a 1.5-ha, seven-year-old red pine plantation containing 0.25-ha of lupine Lupinus perennis, >400 trees were removed to create openings and connect corridors between lupine patches. In February and March 1999–2001, patches of trees (20 × 20 and 5 × 20 m) were removed with bow saws, and in autumn 2001 additional patches were felled with chainsaws. A 0.9-ha, six-year-old red pine plantation was not managed. From 1998–2001, Karner blue butterflies were surveyed 5–6 times/year (covering both flight periods) on a 953-m transect through the managed plantation, and an 890-m transect through the unmanaged plantation. The highest number of butterflies counted on a single date in each flight period at each site was used as the abundance for that year.
Study and other actions tested
Referenced paper
Kleintjes P.K., Sporrong J.M., Raebel C.A. & Thon S.F. (2003) Habitat type conservation and restoration for the Karner blue butterfly: A case study from Wisconsin. Ecological Restoration, 21, 107-115.
A site comparison study in 2003 in a grassland in Uppsala, Sweden (Söderström & Hedblom 2007) reported that grassland strips providing nectar resources or shelter were each more likely to be used by one of four butterfly species than strips with no resources. Results were not tested for statistical significance. Of 31 pearly heath Coenonympha arcania released on a flower-rich strip with no shelter, 12 flew along it, compared to 4/27 released on a sheltered strip with few flowers, and 5/30 on a strip with few flowers and no shelter. Of 27 mazarine blue Polyommatus semiargus released on the sheltered strip, 11 flew along it, compared to 4/29 on the flower-rich strip, and 5/29 on the unsheltered strip with few flowers. The numbers of common blue Polyommatus icarus and ringlet Aphantophus hyperantus which flew along strips were similar between strip types (see paper for details). Three 30 × 2 m strips of long grass (21–28 cm high) were created in a field. One strip had abundant nectar resources but no shelter, one had nectar resources removed but was sheltered by a plantation on one side, and one had neither nectar resources nor shelter. The surrounding grassland was cut to 2–4 cm. From 27 June–16 July 2003, butterflies were caught in the morning in six grasslands, and transported to the experimental site (<20 km). Each day, 2–4 individuals/species were released, one-by-one, from the north end of each strip. Butterflies were followed for two minutes, and the distance and direction travelled were recorded.
Study and other actions tested
Referenced paper
Söderström B. & Hedblom M. (2007) Comparing movement of four butterfly species in experimental grassland strips. Journal of Insect Conservation, 11, 333-342.
A study in 2014 in a restored grassland and oak barren landscape in Indiana, USA (Shuey et al. 2016) reported that regal fritillary Speyeria idalia were found across a restored, connected grassland landscape. Results were not tested for statistical significance. Eighteen years after restoration began, the abundance of regal fritillaries in the restored area peaked at 12–19 butterflies/30-minute transect, compared to 12 butterflies/transect on remnant prairies, and 0 butterflies/transect in an agricultural field. In addition, fritillaries were present in ≥17 habitat patches ≤16 km from the restoration area. Prior to restoration, authors reported that regal fritillaries were only found at three small sites in the landscape. Beginning in 1996, over 3,240 ha of agricultural land was restored to native grassland and oak barrens by planting seed mixes containing over 620 native species, to reconnect remnant grasslands and oak barrens. In addition, seeds and plugs of arrowleaf violet Viola sagittata and bird's-foot violet Viola pedata were planted as host plants. The area was managed to control invasive species and, once established, patches were burned on a three-year rotation. From May–September 2014, butterflies were surveyed every two weeks on 30-minute transects at nine sites across the landscape: five restored sites, two remnant prairies, one old field, and one site still in agricultural production. In 2014–2015, suitable habitat surrounding the restoration area was searched for regal fritillaries.
Study and other actions tested
Referenced paper
Shuey J., Jacquart E., Orr S., Becker F., Nyberg A., Littiken R., Anchor T. & Luchik D. (2016) Landscape-scale response to local habitat restoration in the regal fritillary butterfly (Speyeria idalia) (Lepidoptera: Nymphalidae). Journal of Insect Conservation, 20, 773-780.

Please cite as:

Bladon A.J., Smith R.K. & Sutherland W.J. (2022) Butterfly and Moth Conservation: Global Evidence for the Effects of Interventions for butterflies and moths. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.