Historical observations for a sparsely recorded woodland butterfly are used to determine factors driving distribution change and to identify conservation strategies
A dataset of 1621 records of the butterfly Limenitis populi from 1960 to 2018 was compiled using data gathered in France. Limenitis populi is a poorly recorded species with a mean of 27.2 ± 14.6 records per year during this period. The aim of the study was to describe and evaluate the impact of global warming since the 1990’s on the phenology and rang in France. Using linear mixed models, we estimated a delay in adult emergence of 0.07 days per 100 m increase in altitude and an advance of 0.33 days per 1 °C of mean temperature increase. Since 1960, the mean altitude of L. populi populations has increased by 321.9 m over the last 58 years, corresponding to a gain of mean temperature of 1.74 °C during this period. By comparing projections from climatic models, 60.2% of the suitable area predicted prior to 1990 has since been lost due to warming conditions. Lowlands are more affected by a decline in areas sheltering L. populi than montane regions probably because lowland populations cannot shift to higher altitudes as a means of mitigating the effect of global warming. In addition, changes in the rural landscape may lead to the possible decline of the larval food plant Populus tremula, thus affecting butterfly abundance. In terms of conservation strategy. Implications for Insect Conservation : The key points are (1) to avoid cutting the host plant in montane areas where climatic constraints are not a threat, and (2) to develop forest patches that include P. tremula in lowlands to locally limit the effect of global warming.