Restore or create wetlands and floodplains

Overall effectiveness category Awaiting assessment
Number of studies: 3
Share Tweet Email

View assessment score

How is the evidence assessed?

Effectiveness

not assessed
Certainty

not assessed
Harms

not assessed

Calculating overall effectiveness category

Background information and definitions

Wetland habitats are often drained or degraded during the development of agriculture or expansion of urban areas or other land uses. Restoration of these habitats can help to recover specialist butterfly and moth populations. Restoration of wetlands may involve a combination of interventions, such as removing invasive and emergent plants, maintaining bankside vegetation and trees, planting native species, and raising water levels or reinstating seasonal flooding.

Habitats within this action include wet grassland, fenland and floodplains. For studies on restoring dry grassland, see “Restore or create grassland/savannas”. For studies on restoring peatland, bogs, mires and wet heathland, see “Restore or create peatland”. For studies on the creation of smaller areas of water, see “Create scrapes and pools”.

This action includes studies where either multiple actions have been used to restore or create wetlands and floodplains, or where the specific action used is not clear. For studies of specific actions for creating, restoring, or managing wetlands and floodplains, see “Replant native vegetation”, “Manage wetlands or ponds by grazing or cutting to prevent succession” and “Natural system modifications – Use prescribed fire to maintain or restore disturbance in grasslands or other open habitats”.

Study locations

Key messages

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

COMMUNITY RESPONSE (1 STUDY)

Richness/diversity (1 study): One replicated, site comparison study in Sweden found that wetland creation increased macroinvertebrate diversity (including butterflies and moths), and that species richness increased with wetland age and was similar to mature ponds.

POPULATION RESPONSE (2 STUDIES)

Abundance (1 study): One site comparison study in the USA found that wetland prairie restored by seeding willow dock and seasonal flooding had a higher abundance of great copper eggs than degraded, unflooded prairie.
Survival (1 study): One site comparison study in the USA found that the survival of great copper eggs and caterpillars was lower in wetland prairie restored by planting native seed mixes and flooding annually than in degraded, unflooded prairie.

BEHAVIOUR (1 STUDY)

Use (1 study): One site comparison study in the USA found that wetland prairie restored by planting native seed mixes and flooding annually was used more by adult great copper than degraded, unflooded prairie.

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 site comparison study in 2004–2005 in three wetland prairies in Oregon, USA (Severns et al. 2006, same experimental set up as 3) found that restored wetland prairies were used by adult great copper Lycaena xanthoides more than degraded prairies, but egg survival was lower in restored areas. In two restored wetlands, the proportion of marked butterflies which were recaptured in the area (26 out of 32 butterflies) was higher than at an unrestored site (3 out of 16 butterflies). However, the survival of eggs to large caterpillars in restored, flooded sites (2 out of 84 eggs) was lower than in unrestored, unflooded sites (7 out of 46 eggs). In the late 1990s, two wetland prairies (16–26 ha) were partially restored by planting a wetland prairie vernal pool native seed mix, and flooded annually. Unrestored parts of both sites, and a third, 76-ha, unrestored site, remained dominated by non-native grasses and did not flood. From late summer 2004–June 2005, eggs on 24 willow dock Rumex salicifolius plants in either restored, flooded areas or unrestored, unflooded areas, were revisited monthly to record survival to large caterpillars. From July–August 2005, every 3–4 days, butterflies were caught, marked, released and recaptured in a 1–2.9 ha area with a high density of willow dock at each site.
Study and other actions tested
Referenced paper
Severns P.M., Boldt L. & Villegas S. (2006) Conserving a wetland butterfly: quantifying early lifestage survival through seasonal flooding, adult nectar, and habitat preference. Journal of Insect Conservation, 10, 361-370.
A replicated, site comparison study in 2004 in a lowland agricultural region in southwest Sweden (Thiere et al. 2009) found that wetland creation increased macroinvertebrate diversity, including butterflies and moths. From 0–8 years after creation, wetlands contained 6–51 aquatic macroinvertebrate species, and the estimated addition to regional species richness ranged from 1–33 species/created wetland. Species richness increased with wetland age (data presented as model results). Species richness in created wetlands (32 species/pond; 176 species total) was similar to existing mature ponds (37 species/pond; 178 species total). From 1996–2004, about 300 ha of wetlands (each <2 ha) were created in natural depressions of former pasture, crop or fallow land by soil excavations and damming existing waterways or drainage systems. In three sub-regions with low, moderate and high densities of created wetlands, 15% (i.e. 13, 8, and 15 wetlands) were surveyed in May 2004, by sweeping a D-shaped hand-net twice at 15 points along each wetland margin. Sampled wetlands were all permanent, flow-through water bodies. Ten mature ponds (>50-years-old) in the region had been sampled at intervals in April 1996–2003.
Study and other actions tested
Referenced paper
Thiere G., Milenkowski S., Lindgren P.E., Sahlen G., Berglund O. & Weisner S.E.B. (2009) Wetland creation in agricultural landscapes: biodiversity benefits on local and regional scales. Biological Conservation, 142, 964-973.
A site comparison study in 2007 in two wetland prairies in Oregon, USA (Severns 2011, same experimental set up as 1) found that great copper Lycaena xanthoides laid more eggs on willow dock Rumex salicifolius plants in restored, seasonally flooded wetlands than in degraded, unflooded areas, but egg survival was lower in restored wetlands than in unflooded habitats. In restored, seasonally flooded wetlands, great copper eggs were present on more of the available willow dock plants (10 out of 14 plants) than in degraded, unflooded areas where plants were surrounded by tall, non-native grasses (6 out of 37 plants), and the number of eggs/plant was higher (restored: 0–9 eggs/plant; degraded: 0–3 eggs/plant). However, the authors noted that egg survival was lower in flooded areas than in unflooded habitat (see 1 - Severns et al. 2006). In the late 1990s, several thousand willow dock were seeded in two 0.8-ha, seasonally flooded, restored wetlands. Each restored area was surrounded by degraded, unrestored, unflooded habitat. In August 2007, every willow dock plant at each site was searched for great copper eggs. Plants were categorized as growing in either flooded or unflooded habitat.
Study and other actions tested
Referenced paper
Severns P.M. (2011) Habitat restoration facilitates an ecological trap for a locally rare, wetland-restricted butterfly. Insect Conservation and Diversity, 4, 184-191.

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.