Encourage natural regeneration in former plantations or logged forest

Supporting evidence from individual studies

1. A site comparison study in 1996 in a logged tropical rainforest in south-east Côte d’Ivoire (Fermon et al. 2000) found that the abundance, species richness and diversity of fruit-feeding butterflies (Nymphalidae) were similar in naturally regenerating forest and forest managed by thinning, but rarer species were caught more frequently in regenerating forest. Naturally regenerating forest had a similar abundance (56 individuals/trap), species richness (71 species) and diversity (data presented as model results) of butterflies to forest managed by thinning (abundance: 54 individuals/trap; richness: 76 species). However, species with smaller geographic ranges were caught more frequently in naturally regenerating forest (data presented as model results). See paper for individual species results. From 1960–1990, a 216 km² forest was selectively logged. From 1992 the forest was protected, and two management options were implemented: natural regeneration (no management) and liberation thinning. Liberation thinning was designed to promote the growth of commercial timber species, and included cutting of lianas and climbers, and killing some non-commercial trees. Rare trees and important fruit trees were protected. From January–March 1996, butterflies were sampled in 30 ha of naturally regenerating forest, and 30 ha of thinned forest, using 28 banana-baited traps in each habitat. Traps were set 1 m above ground, 100 m apart, for six consecutive days, and checked daily.

   Study and other actions tested

   Referenced paper

   Fermon H., Waltert M., Larsen T.B., Dall'Asta U. & Muehlenberg M. (2000) Effects of forest management on diversity and abundance of fruit-feeding nymphalid butterflies in south-eastern Cote d'Ivoire. Journal of Insect Conservation, 4, 173-189.

2. A replicated, site comparison study in 2001–2002 in 18 forest stands in Ibaraki Prefecture, Japan (Taki et al. 2010) reported that naturally regenerating forests had a higher abundance and species richness of moths than plantations, and found that the moth community changed with forest age. In naturally regenerating forests, 286–979 individuals of 121–220 species/stand were recorded, compared to 68–672 individuals of 50–192 species/stand in plantations (statistical significance not assessed). In naturally regenerating forests, the abundance and species richness of moths was similar between young (abundance: 344–849 individuals/stand; richness: 132–177 species/stand), mature (abundance: 375–979 individuals/stand; richness: 125–220 species/stand) and old (abundance: 286–682 individuals/stand; richness: 121–171 species/stand) forests, but the species community was different (data presented as model results). Six species were associated with young, 71 with mature, and 43 with old naturally regenerating forest. In mature plantations, the abundance (151–672 individuals/stand) and species richness (84–192 species/stand) of moths was higher than in young plantations (abundance: 68–271 individuals/stand; richness: 50–117 species/stand). Ten forest stands (2.5–32.5 ha) had been naturally regenerating for 1–178 years, and eight conifer plantations (2.6–14.3 ha) were planted 1–74 years ago. Forests were divided into three age classes (young: <20 years old; mature: 20–100 years old; old: >100 years old (natural regeneration stands only)). In August 2001–2002, moths were sampled on two nights/year using one 6 W black-light trap in each plantation forest (in 2001) and naturally regenerating stand (in 2002). Species with fewer than three individuals in each forest type were excluded.

   Study and other actions tested

   Referenced paper

   Taki H., Yamaura Y., Okochi I., Inoue T., Okabe K. & Makino S. (2010) Effects of reforestation age on moth assemblages in plantations and naturally regenerated forests. Insect Conservation and Diversity, 3, 257-265.

3. A site comparison study in 2007 and 2009 in an area of rainforest in the Central Region, Ghana (Sáfián et al 2011) found that naturally regenerated secondary forest had lower observed butterfly species richness than primary forest and similar richness to a clear-cut area and forest replanted nine years ago, and lower butterfly community diversity than primary forest and the clear-cut area. Similar numbers of species were recorded in secondary forest (51) to a clear-cut area (53) and nine-year-old replanted forest (54), all of which had fewer species than primary forest (62). However, when taking into consideration the number of rare and common butterflies seen, for all four indices calculated, secondary forest had lower estimated richness (62–73) than the clear-cut area (77–128). Butterfly community diversity was lower in secondary forest than primary and clear-cut forest (data presented as diversity indices). Differences between habitat types were not tested statistically. Butterfly community compositions in the naturally regenerated secondary forest, replanted forest and primary forest were more similar to each other than to the clear-cut area, but naturally regenerated secondary forest was more similar to replanted forest than primary forest (data presented as similarity index results). Four habitat patches were surveyed, all within a 40 ha area and ~250 m apart from each other, on the boundary of Kakum National Park: young forest planted nine years ago with Ceiba pentandra, Chlorophora excelsa, Terminalia ivoriensis and Khaya ivoriensis, middle-aged naturally regenerated secondary forest, old primary forest and an area which was previously primary forest but was clear cut one year prior to the first surveying year. Patch sizes were not given. Eight banana-baited traps were established 30 m apart in each of the patches, and operated for 12 consecutive days, three times each in 2007 and 2009. Butterflies were collected from traps daily.

   Study and other actions tested

   Referenced paper

   Sáfián S., Csontos G. & Winkler D. (2011) Butterfly community recovery in degraded rainforest habitats in the Upper Guinean Forest Zone (Kakum forest, Ghana). Journal of Insect Conservation, 15, 351-359.

4. A replicated, site comparison study in 2011–2012 in a tropical rainforest in Uganda (Nyafwono et al. 2014) found that naturally regenerating forest had a similar abundance and species richness of butterflies to pristine forest, but abundance and richness were highest 12–25 years after felling. Two former plantations which were clearcut 12–25 years earlier and left to regenerate naturally had a similar abundance (18–21 individuals/trap) and species richness (31–34 species/trap) of butterflies to one pristine forest site (abundance: 24 individuals/trap; richness: 32 species/trap). However, those three sites had a greater abundance and species richness than both a second pristine site (abundance: 12 individuals/trap; richness: 24 species/trap) and four other sites which were clearcut 7–12 years earlier (abundance: 8–10 individuals/trap; richness: 20–23 species/trap) or were heavily logged 42–44 years earlier and left to regenerate naturally (abundance: 7–10 individuals/trap; richness: 22–24 species/trap). In 1968–1969, two areas of forest (347–622 ha) were heavily logged (40–50% basal area reduction, one area treated with arboricide) and left to regenerate naturally. From 1987–2004, four former conifer plantations (60–171 ha) were clearcut and left to regenerate naturally for 7–10, 10–12, 12–17 and 17–25 years. Two areas of intact pristine forest (282–754 ha) were also studied. From May 2011–April 2012, butterflies were caught from 0800–1600 hours on three consecutive days/month in 8–13 banana-baited white cylindrical butterfly traps (125 × 35 cm, hung at 40–50 cm height) in each area.

   Study and other actions tested

   Referenced paper

   Nyafwono M., Valtonen A., Nyeko P. & Roininen H. (2014) Butterfly community composition across a successional gradient in a human-disturbed Afro-tropical rain forest. Biotropica, 46, 210-218.