Driftability and niche construction

Niche construction is the process of organisms changing themselves or their environment—or their relationship with their environment—in ways that affect the evolutionary trajectory of their population. These evolutionary trajectory changes are traditionally understood to be triggered by changes in selection pressures. Niche construction thus necessarily involves organisms altering selection pressures. In this paper, we argue that changes in selection pressures is not the only way organisms can influence the evolutionary futures of their population. We propose that organisms can also affect drift probabilities, and that such changes should be considered niche construction. Drift probabilities can be modulated by altering population size or by affecting driftability (individual variance in possible reproductive outcomes). We consider both and provide examples of how niche construction can stabilize, increase, or dampen drift probabilities. Finally, we revisit and broaden the traditional definition of niche construction. We hold that organismic activities that modify drift probabilities should count as niche construction, even if selection pressures remain unaltered.