Data from: Urban forest fragments as unexpected sanctuaries for the rare endemic ghost butterfly from the Atlantic forest.

Anthropogenic land expansion, particularly urbanization, is pervasive,
dramatically modifies the environment and is a major threat to wildlife
with its associated environmental stressors. Urban remnant vegetation can
help mitigate these impacts and could be vital for species unable to
survive in harsh urban environments. Although resembling non-urban
habitats, urban vegetation remnants are subject to additional
environmental stresses. Here we evaluate the occurrence and density of the
endemic ghost butterfly (Morpho epistrophus nikolajewna), that was once
common, in the highly fragmented Atlantic forest of NE Brazil. We tested
whether this butterfly would be found at lower densities in urban forest
fragments of contrasting sizes as opposed to rural ones, given the number
of environmental stressors found in urban areas. We surveyed 14 forest
fragments (range 2.8 to over 3000 ha) of semi-deciduous Atlantic forest in
rural and urban locations using transect based distance sampling. The
ghost butterflies showed strong seasonality; flying only from April to
June. They were only identified in an urban fragment (515 ha), with an
estimate of 720 individuals and a density 1.4 ind/ha. All forest fragments
had experienced some level of logging in the past, which might have had an
effect in the butterfly population. Nevertheless, rural forest fragments
were subject to increased particulate matter concentrations, associated to
biomass burning, that we suggest might have had a more influential role
driving the collapse of rural populations. Our findings show the
importance of urban forest remnants to sustain population of this
endangered species.