Hoist the colours: silviculture impacts butterfly assemblage colours in the Atlantic Forest

Abstract

Organismal colours have long captivated and inspired naturalists and scientists. Since colours depend on species' life history, it is expected that they respond to environmental changes, especially in an increasingly anthropized world. Aiming to evaluate how this trait responds to different anthropogenic disturbances, we assess wing colour aspects of fruit-feeding butterflies sampled in Atlantic Forest remnants. These remnants, with well-defined understory and canopy, are crossed by roads and trails acting as artificial edges and besiege exotic pine silviculture areas of different ages, representing landscapes commonly found in the subtropical Atlantic Forest. Through standardised photographs, we obtained colour measurements of brightness, saturation, contrast, colour diversity and heterogeneity, plus the presence of eyespots and iridescence for dorsal and ventral wing surfaces of 47 butterfly species, and evaluated their distribution and abundance in the distinct environments. We hypothesise colour variables will differ in each environment due to their biotic and abiotic differences, being less diverse in anthropized ones due to the pressures generated by disturbances. As expected, different natural environments have diverse and unique colour traits that are not found in anthropized ones; however, artificial edges present brighter and even more diverse colours. Pine silviculture areas, despite differing succession stages, all have decreases in colour diversity. We demonstrate that different anthropogenic actions can lead the most colourful species to disappear. Therefore, we argue butterfly colouration can be seen as a bioindicator, representing a useful form of functional biodiversity, providing conservation status and facilitating communication with the general public.