Consideration of the properties of the sources of selection potentially helps biologists to account for variation in selection. Here we explore how the variability of natural selection is affected by organisms that regulate the experienced environment through their activities (whether by constructing components of their local environments such as nests, burrows, or pupal cases, or by choosing suitable resources). Specifically, we test the prediction that organism-constructed sources of selection that buffer environmental variation will result in reduced variation in selection gradients, including reduced variation between (i) years (temporal variation), and (ii) locations (spatial variation), and (iii) weaker directional selection, relative to non-constructed sources. Using compiled datasets of 1045 temporally replicated, 257 spatially replicated, and a pooled dataset of 1230 selection gradients, we find compelling evidence for reduced temporal variation and weaker selection, in response to constructed compared to non-constructed sources, and some evidence for reduced spatial variation in selection. These findings, which remained robust to alternative datasets, taxa, analytical methods, definitions of constructed/non-constructed, and other tests of reliability, suggest that organism-manufactured or chosen components of environments may have qualitatively different properties from other environmental features.