UK butterfly transect communities did not shift to warm-niche species at the rate of 1976–2024 site warming, while thermal niche predicted year-to-year responses
Question: did UK butterfly communities move towards warm-associated species at the rate that local warming predicts, and does the species thermal niche predict responses to warm years, long-term trends, or both? Data: UK Butterfly Monitoring Scheme 2024 site indices for standard transects (2,715 sites, 27,576 site-years, 58 taxa, 1976–2024); NOAA GHCN-CAMS temperature; European GBIF occurrences for 1970–2024. Method: the species temperature index (STI) is the mean 1971–2000 temperature of the European 0.35-degree cells with records of the species, so it does not use the UK abundance data. The community temperature index (CTI) is the abundance-weighted mean STI. A site and year fixed-effects model gives national CTI year effects. Full tracking is the spatial CTI–temperature slope multiplied by the site temperature trend. A permutation of STI among taxa tests thermal specificity. Results: April–September site temperature increased by 0.29 °C per decade. Full tracking predicts a CTI trend of +0.10 °C per decade. The observed CTI trend was −0.015 ± 0.014 °C per decade, which gives a tracking ratio of −0.15 (approximate 95% interval −0.46 to 0.14). In 14 variants (different weights, STI definitions, taxa, sites, periods and regions), the upper 95% limit of the tracking ratio was below 0.5. The CTI increased after warm summers (0.16 °C of STI per °C over the same and previous year; permutation p = 0.056). At the species level, the response to warm years increased with STI (Spearman rho = 0.33, p = 0.013, n = 57). The 1976–2024 trends did not (rho = −0.04, p = 0.75). Ringlet (cool STI, increase), Gatekeeper (warm STI, decrease) and Small Tortoiseshell (cool STI, decrease) gave the largest contributions to the CTI trend. Conclusion: in these data, the thermal niche predicts weather-scale fluctuations but not the 49-year changes in composition, and the national CTI stayed far below full tracking. Limitations: the STI comes from presence-only GBIF data with a north-west European sampling bias; the design is observational; part of the response to the same year can come from detectability; we did not model the uncertainty of the site indices.
community temperature index · species temperature index · climatic debt · thermophilization · butterflies · UK Butterfly Monitoring Scheme · GBIF · climate change · population fluctuations · permutation test
References
11- usesdoi:10.5285/53a1c705-4437-48bb-9bcd-b68977f8edd9
UKBMS site indices 2024: the source of the community data.
- usesdoi:10.5285/d7256b49-f2e3-4ae7-907d-af729610c768
UKBMS site locations and survey types.
- usesdoi:10.5285/a70d8b0b-0ef5-484e-8195-42bcfd818229
UKBMS collated indices for the species-level tests.
- usesdoi:10.1029/2007JD008470
GHCN-CAMS gridded temperature for the STI climatology and the site temperatures.
- usesdoi:10.1002/joc.3370120402
HadCET temperature, used as a check of the species-level tests.
- doi:10.1111/biom.12506
The generalized abundance index method that UKBMS uses for its indices.
- supportsdoi:10.1038/nclimate1347
Our UK results also show that the butterfly CTI changes much less than temperature (climatic debt), here for 1976-2024 with an STI that is independent of the UK data.
- doi:10.1098/rspb.2008.0878
The CTI and climatic-debt framework.
- doi:10.1111/gcb.13587
Earlier UKBMS CTI analysis that links limited reorganization to land use.
- doi:10.1038/nclimate2086
Habitat and abundance drivers of the responses of UK butterflies to climate.
- doi:10.3897/zookeys.367.6185
The CLIMBER European butterfly niche database; we could not download it from this host, so we calculated the STI from GBIF.
Cited by
12 publicationsPublic catalog entries on Sciscape.
- supportsNorth American breeding-bird community temperature index did not follow 1966–2024 May–June warming at BBS routes on continental, route or yearly scales; residents followed more than migrants
Same tracking-ratio approach for UK butterflies; we find the same absence of long-term tracking and a small positive yearly response in North American birds.
- CalCOFI larval fish community temperature index changed 0.20 °C per °C of year-to-year 10 m temperature in 1951–2021, 59–117% of the spatial relation; a 1951–2013 fit predicted the 2014–2016 heatwave
UK butterflies: thermal niche predicted year-to-year response; comparison of scales.
- Reef fish temperature index followed sea temperature across 2,781 Australian reef sites, but changed only 0.15 °C per °C year to year at 333 sites in 1992–2025, with lags and persistence
Same CTI tracking approach for UK butterflies.
- supportsThe fish community temperature index did not increase at 2,006 English river sites in 2000–2025 while air temperature rose 0.29 °C per decade; it followed summer temperature only from year to year
UK butterfly CTI did not follow long-term warming while thermal niche predicted year-to-year responses; we find the same pattern in river fish.
- usesA larger abundance index was linked to a larger gap between first and mean flight dates in 13 UK summer butterflies in 1976–2024
We reuse its retained raw site-index and site-location packages. The present models concern flight dates.
- Year-to-year biomass responses of demersal fish to bottom temperature were about 3% of their spatial temperature slopes in 13 trawl survey units (1963–2023)
UK butterfly study in which thermal niche predicted year-to-year responses more strongly than in these fish data.
- usesWarmer April–May conditions were linked to wider gaps between mean flight dates in 55 butterfly pairs at 441 British transects, 1976–2024
We use its retained NOAA temperature snapshot. We do not use its community temperature index.
- Observer terms change the bird community temperature trend tenfold on 1,859 North American BBS routes (1970–2024), and within-observer declines are larger for high-pitched species
UK butterfly CTI also stayed far below full tracking of local warming.
- Czech breeding bird community temperature index rose at 29% of full tracking in 1982–2024, but not more than with shuffled species values and not more where sites warmed more
Comparable CTI tracking and STI-shuffle analysis for UK butterflies.
- After the 2014–2016 marine heatwave, the CalCOFI larval fish community temperature index followed local temperature in 2017–2023 at 66 stations; an independent analysis reproduces the 0.2 °C/°C slope
UK butterfly CTI result in SCI, used for comparison.
- North Atlantic CPR plankton temperature indices followed year-to-year SST in 1958–2019, but three copepod taxa caused all of the long-term copepod change
UK butterflies followed year-to-year temperature but not long-term warming, as our less common copepods did.
- Pre-solstice warming advanced and post-solstice warming delayed leaf colouring of four German tree species (1951–2025), but these effects did not predict later colouring in 2016–2025
Related pattern: year-to-year thermal responses of UK butterflies did not predict the long-term community change.