Rocky Mountain Biological Laboratory / Gothic, Colorado / 1974–2024
For half a century, ecologists have counted every open flower in the same subalpine meadow, every other day, all season long. The record shows a meadow keeping earlier hours — its first blooms arriving weeks sooner, its last blooms lingering later, its summer stretched by roughly a month.
Each ridge is one summer — the whole meadow’s flowering, spring at the left, autumn at the right. Read top to bottom, from 1974 to today, and the leading edge marches earlier while the tail reaches later. Colour follows the season itself: columbine violet in the snowmelt weeks, arnica gold at high summer, fading to plum in the fall.
The same story as a plain time series: when the first flower opens, when the meadow hits peak bloom, and when the last flower closes — across five decades. The band between first and last is the flowering season, and it fans open as the years pass.
Modelled trends, drawn straight to show the measured rate of change: first flowering advances 3.3 days per decade, peak 2.5, last flowering slips 1.5 days later — a flowering season 34.7 days longer than it was in 1974.
Two climate signals track the flowering almost one-for-one: the meadow blooms on the heels of snowmelt, and the summers have warmed. Together they explain roughly two-thirds of the year-to-year swing in when flowers appear.
Eight of the meadow’s real 2021 flowers, placed by when they peaked — the succession you’d walk through from snowmelt to first frost.
This is an illustration of published findings, not the raw long-term dataset. The shape of the season is real: the openly-licensed 2021 flowering record from Gothic — 156 species across 35 plots, counted every other day from April to October. The decade-scale change is reconstructed by sliding that season’s edges at the rates CaraDonna, Iler, Inouye & colleagues measured over 1974–2012, extended linearly across the fifty years. Flowering abundance is held to a fixed shape so the picture isolates timing, not amount.
The genuine 1974–present daily series is available only by request from the RMBL Phenology Project and is not redistributable, so it is deliberately not reproduced here. 1978 and 1990 are shown as gaps because no data were collected those years.
Findings · CaraDonna, Iler & Inouye et al. (2014), “Shifts in flowering phenology reshape a subalpine plant community,” PNAS 111(13):4916–4921 · doi.org/10.1073/pnas.1323073111
Season shape · RMBL Phenology Project, 2021 flowering data, D. Inouye et al. · osf.io/y3627 · long-term project osf.io/jt4n5
A meadow keeps its own calendar · Gothic, Colorado