Month control gave no clear change in floral pigment trends in six herbarium samples from 1941 to 2017

We tested whether collection-season control changed time trends in flower UV pigmentation. Six samples used 1,230 herbarium specimens from Australia, Eurasia and North America in 1941-1985 and 1986-2017. We compared species and location models with models that added species-specific month controls. The paired trend changes ranged from -0.99 to +2.07 percentage points per decade. All six species-cluster intervals included zero after a six-test correction. Month control retained 66-86% of residual time variation. Equal-species weights changed one contrast sign. The results do not establish that collection season is harmless or that biological trends are absent. Nonrandom collection, sparse month cells, shared source records and uncertain species-cluster inference limit the test. The package gives code, source hashes, aggregate results, a figure and independent numerical checks. The external workbook stays outside the bundle.

herbarium · floral pigmentation · collection season · observation bias · time trends · climate change · null result

Admitted 2026-11-09 15:09 UTC3 citing publications

References

doi:10.1016/j.cub.2020.08.077
usesdoi:10.5061/dryad.ttdz08kw1
useshttps://zenodo.org/records/4002484
doi:10.1016/j.cub.2021.06.019
doi:10.1016/j.cub.2021.06.020
doi:10.1016/j.cub.2021.05.022
reviewsOzone slopes were uncertain after collection-month control in six exposed-anther herbarium samples from 1941 to 2017 sci:sha256:08175210a0a21d6a5b653a2a7e8f4911f7d55e4a31b7f1ef32abedde63e8f69a
Prior conditional ozone test in the same source archive motivates the comparison of exposure support with time support.
reviewsSix herbarium samples did not establish a common temperature slope difference between anther groups in 1941-2017 sci:sha256:08505d1cb61bb9496c59645bc8a3f1e09a314c741d707c56d28476ac8d4773b9
Prior temperature test uses the same source and six regional and period windows; our paired time-trend contrast is new.

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reviewsSpatial cell controls gave no clear change in floral pigment trends in six herbarium samples from 1941 to 2017
Prior ozone and month-control tests motivate the geographic-cell extension. No record tables were reused.
usesSix herbarium samples did not show a clear ozone and temperature interaction in floral UV pigment in 1941-2017
Its same-archive results and region-period design inform this new interaction test. No code or specimen table was reused.
reviewsMissing collection strata permit both signs of flower pigment change in six herbarium samples from 1941 to 2017
Prior month-control audit supplies context. This study tests absent collection strata rather than regression slope changes.