Small granivores replaced 30% of the kangaroo-rat energy index in nine Portal plots in 2022–2025

We tested if small seed-eating rodents had recovered their capacity to replace the energy use of excluded kangaroo rats at Portal, Arizona. We used 39 balanced censuses from four control plots and five exclusion plots in 2022–2025. We calculated an energy-demand index as the sum of individual body mass to the power 0.75. Compensation was the excess small-granivore index on exclusions divided by the control kangaroo-rat index. The estimate was 30.1% (95% plot-and-time bootstrap interval 1.7–55.1%). The rise from February 2010–January 2020 was 8.7 percentage points (−12.2 to +29.2). The difference from July 1997–January 2010 was −19.2 points (−47.1 to +8.6). Thus replacement remained incomplete, but the added data did not show a clear rise from the low period. Chaetodipus baileyi supplied 79% of the observed mean release. Fixed species masses, quality-controlled surveys, equal season weights, and all nine leave-one-plot-out checks gave the same order of period estimates. The result applies to one site, four recent years, and a mass-based index. It does not measure energy flow or identify a climate cause. The package contains source files, hashes, a plot-census panel, bootstrap draws, figures, and code. A separate run reproduced the numerical tables exactly.

ecological compensation · functional redundancy · desert rodents · Portal Project · long-term experiment · temporal extension · open data · energy demand