DOI: 10.5061/dryad.mgqnk996v
title: Habitat management interventions for a specialist mid- successional grassland butterfly, the Lulworth Skipper

description: Evidence-based management is needed to reverse declines in insect
 abundance. The Lulworth Skipper Thymelicus acteon is a range-restricted
 and declining species associated with mid-successional grassland,
 presenting challenges because interventions are necessary to prevent
 long-term habitat deterioration but can result in short-term reductions in
 quality. In addition, site management should be compatible for the focal
 species and for wider plant and insect diversity. We conducted factorial
 experimental management trials to understand effects of cutting and
 rotovation on the height and structure of vegetation containing the larval
 host plant Tor-grass Brachypodium rupestre. We monitored vegetation
 height, B. rupestre cover and plant diversity, and T. acteon larval
 presence over four years. Rotovation and cutting differed in their effects
 on habitat structure and larval occupancy relative to controls.
  Vegetation height and host plant cover, the most important
 components of habitat quality for T. acteon, were faster to recover to
 suitable levels on cut plots. However, larval occupancy increased more
 quickly on rotovated plots, where plant species diversity was also higher.
 Results suggest that due to initial negative impacts of interventions on
 T. acteon occupancy, low frequency or intensity management, such as
 managing sections of a site every three years, is advisable.
description: # Habitat management interventions for a specialist mid- successional
 grassland butterfly, the Lulworth Skipper
 [https://doi.org/10.5061/dryad.mgqnk996v](https://doi.org/10.5061/dryad.mgqnk996v) The dataset contains two csv files; \- plotdata_2018_2021 contains the data used to look at effects on larval occupancy including the descriptive summary, Kruskal Wallis Tests and GLMMs on larval occupancy. \- plotdata_simpsons contains similar data to the above but with an extra column on plant diversity index (Simpsons). The results are based on management trial plots in a factorial design, whereby effects of cut and rotovate on Lulworth Skipper occupancy were tested. Data includes habitat information on vegetation height and food plant frequency. ## **Description of the data and file structure** The column headings are as follows: year = year of survey sites = sites plot = plot ID replicate = replicate ID treatment = plot treatment cut = whether a plot was cut (1) or not cut (0) rotovate = whether a plot was rotovated (1) or not rotovated (0) spring.veg = mean spring vegetation height (cm) spring.coef = coefficient of variation from spring vegetation measurement s summer veg = mean summer vegetation height (cm) summer.coef =coefficient of variation from summer vegetationmeasurements bp.freq = percentage cover of Brachypodium (larval host plant) prop.bp = proportion cover of Brachypodium rupestre aug.veg.prev.year = mean summer vegetation height from previous year time = time since intervention, number of growth seasons (1=2018, 2 = 2019, 3 = 2020, 4 = 2021) larvae.status = whether the plot was occupied (1) or unoccupied (0) by larvae aug.coef.prev.year_check - the coefficient of variation (indicator of vegetation structure) for the plots for the previous year **Plotdata_simpsons** This spreadsheet, contains the plant diversity files the rows are labelled above are the same, and the additional rows are as follows; rowid - row number (unique identifier) sim_ind - simpsons index of plant diversity