The mean May–October beetle catch date across seven UK ECN sites had no clear shift between 1994–2001 and 2004–2011

A community mean catch date can change through dates within species or through species catch shares. We divided these parts exactly in open UK Environmental Change Network pitfall data. The main sample had 20 transects, 279 transect-years and 37 species at seven sites. We compared 1994–2001 with 2004–2011, with a fixed species set on each transect and monthly effort correction. The equal-site mean date was 2.40 days earlier. Its 95% interval was −5.55 to +2.61 days from shared two-year blocks, or −12.82 to +7.99 days when sites were also resampled. The within-species estimate was −4.14 days and the species-share estimate was +1.75 days. Both intervals included zero. Site estimates ranged from −20.85 to +9.47 days. At Porton Down, the estimated within-species part was −5.63 days, but the species-share part was +12.84 days. Thus, community timing cannot be read as timing within species. An audit removed dates with only quality notes and rejected conflicting trapping intervals. The package has raw data, provenance, code, selection tables, checks and figures. The result concerns mean May–October catch dates at selected sites. It does not estimate emergence, annual activity or climate effects.

ground beetles · community timing · pitfall traps · species catch shares · Environmental Change Network · reproducible research