Studies on butterflies’ diversity in relation to habitats and seasons at Gulele Botanical Garden in Central Ethiopia: implication of protected area for in-situ conservation of biological entity

Abstract

Butterflies are the most important biodiversity components, which are under different threats including climate change that varies with habitat type and seasons. Intra-annual variation in temperature (i.e. seasonality) can have important implications for thermal tolerance, which affect climate change vulnerability. Habitat type can additionally influence a population’s capacity to respond to climatic change. As Gullele Botanical garden is home of small animals like butterflies owing to its different habitats in different seasons, studying the diversity of these useful group of organism is vital. The study was conducted from July 2012 to June 2014. Butterfly diversity was investigated using sweep nets along transects (500 m x 300 m) in three types of habitats: natural forest, artificial forest and Grassland. Data were analyzed using Xcel Software, Tukey’s hsd test and diversity indexes. Maximum abundance (162) and species richness (26) was recorded in grassland followed by natural forest though they are not statistically different (p>0.05). Butterflies evenly distributed in the three habitats (P>0.05). The highest Shannon diversity index was at the grassland (H=3.09) followed by the natural forest (H=3.02). The species richness index was the highest (R=4.91) in the grassland and the least (R=3.79) in the artificial forest. Simpson’s diversity index indicated higher butterfly species diversity in the natural forest (D=0.92) and grassland habitat (D=0.96). Members of the family Lycaenidae were the most dominant (28.5%) and Hesperidae (8.03%) was the least. There was a significance difference (P<0.05) among seasons. Multiple comparisons of Tukey hsd test showed that there was a significant (P<0.05) difference between autumn and winter. Species richness showed the maximum (R=6.06) record in autumn and minimum (R=4.10) in winter. Shannon diversity index showed higher diversity (H=3.396) in autumn. Among families, Lycaenidae had high values in autumn (H=1.09) and spring (H=1.03), while Nymphalidae and Pieridae had high values during winter (H=0.952) and summer (H=0.980), respectively. Hesperiidae had the highest value (H=0.32) in autumn and the lowest (H=0.00) in winter. In Artificial forest Hypolimnas salmacis (Rothschild & Jordan), Bicyclus campus (Karsch) and Euchrysops albistriata (Capronnier) were abundantly found. Deudorix dinochares (Grose-Smith) and Papilio echerioides (Trimen,) were species specific to the natural forest habitat. The most abundant species in the grassland were Eicochrysops messapus (Wallengren), Colias electo (Berger) and Danaus chrysippus (L.).