Temporal patterns of butterfly diversity at Saltfleetby National Nature Reserve, Lincolnshire

Abstract

Insect communities play a vital role in providing ecosystem services which benefit both ecological processes and human society. However, insect populations are declining across the world in response to factors such as climate change, agricultural intensification, and habitat destruction. Butterflies are highly studied because they are key indicators of insect population response in general due to their high sensitivity to environmental factors. Using butterfly abundance data from 1977 to 2022 at the Saltfleetby-Theddlethorpe Dune National Nature Reserve in the UK, this study aimed to identify patterns between butterfly biodiversity and time. Data was collected from a 2.8km transect line walked by volunteers between 9 and 24 times per year. It was hypothesised that, due to national distributional changes as a result of changing climate, species richness and diversity would increase over time but assemblage dissimilarity would change. Additionally, it was expected that minimum temperature and rainfall would have an impact on the abundance of individual species and that species will have a varying response to climatic and environmental factors, with some species becoming absent or present due to national distributional changes and some species responding well to an increase in temperatures. The results of this study showed a significant increase in species diversity over the course of the survey alongside an increase in assemblage dissimilarity. Average annual Minimum temperature had a positive relationship with butterfly diversity but had varying effects on the abundance of individual species. This study concluded that climatic changes have likely had a positive effect on overall butterfly biodiversity at the Saltfleetby? Theddlethorpe Dune National Nature Reserve (hereafter referred to as Saltfleetby). However, declines in certain species could be caused by indirect effects of these changes, such as a decrease in larval host plants or a change in species distribution. These findings can be used to make general inferences about trends in other insect species at Saltfleetby, but further investigations into the causes of these trends will be beneficial in improving and maintaining these habitats and species populations.