Small heath
The small heath (Coenonympha pamphilus) is a butterfly species belonging to the family Nymphalidae, classified within the subfamily Satyrinae (commonly known as "the browns"). It is the smallest butterfly in this subfamily. The small heath is diurnal and flies with a noticeable fluttering flight pattern near the ground. It rests with closed wings when not in flight. It is widespread in colonies throughout the grasslands of Eurasia and north-western Africa, preferring drier habitats than other Coenonympha, such as salt marshes, alpine meadows, wetlands, and grasslands near water (i.e. streams). However, habitat loss caused by human activities has led to a decline in populations in some locations.
The larval host plants are grasses, found in various habitats, while adult butterflies feed on nectar from flowers. The males of this species are territorial, which plays a large role in obtaining a female mate. To establish dominance, they partake in lekking, a mating display in which males aggregate in a competitive display to attract passing females.
The small heath is spread throughout the Western Palearctic, particularly in Europe where it has been reported in at least 40 different countries since 2002. It is commonly found in the United Kingdom, largely in England and Wales. Populations are also found in southwest Siberia, regions of Asia, and north Africa.
As a grasslands species, the small heath prefers open habitats with shorter grass compared to other related species. It is also found in an extensive range of environments including meadows, heaths, mountains (in the subalpine zone), and alongside railways. It has been sighted in calcareous grasslands throughout nineteen countries in Europe. For mating and oviposition, small heath butterflies prefer territories that are close to vegetation over areas that are open and clear.
The small heath also resides in biodiverse patches of green habitats (i.e. greenways, gardens, and parks) in urban areas. These fragments create less-isolated corridors throughout cities, which help butterflies disperse throughout this habitat.
Overall, the small heath is generally common and abundant throughout its geographic distribution, particularly in Europe. Urban habitats have become a significant focus in the conservation of the small heath due to the widespread green fragments forming chains of ecological biodiversity. In a study of elevated atmospheric CO2 levels on development, it was determined that larval development time increased due to elevated CO2 levels, suggesting an effect of CO2 on larval performance. Additionally, it was found that food-plant preferences of larvae might also be affected, which could play a future evolutionary role, although this is an area that requires further research.
As a grassland species, the effects of intense, widespread agriculture is a concern for the welfare of the small heath. Grassland management through periodic ecological disturbances (i.e. mowing) is considered necessary to maintain "semi-natural" grasslands. Negative effects of mowing include the loss of biodiversity, the conversion of natural grasslands into agricultural fields, mortality, and loss of nectar resources. However, a study shows that such disturbances of these habitats may actually lead to an increase in the population of grassland butterflies including the small heath.
