Evolution of Plant Niche Construction Traits in Biogeomorphic Landscapes.

AbstractBy virtue of their niche construction traits, plants play a significant role in shaping landscapes. The resultant outcome could change the selective environment, which then influences the evolution of these same plants. To date, almost all biogeomorphic models have assumed that niche construction traits are invariant in time. Conversely, niche construction studies often assume that independent abiotic changes either are nonexistent or are simply linear. Here, I consider the concomitant evolution of plant niche construction traits during complex landscape development. I construct a geo-evolutionary model that couples a population genetic module with a landscape development module. Allowing plants to evolve always results in landforms different from those that appear when evolution is not included. The topographic difference between cases with and without evolution ranges from a small difference in steady-state elevation (topography) to pronounced differences in landforms. Furthermore, evolution of niche construction traits could introduce alternative stable states and hysteresis, modifying the responses of landscapes to environmental stress. Allowing the landscape to develop while evolution occurs alters evolutionary trajectories for niche construction traits. The system can even develop into states that suppress natural selection. Model results support the need to integrate niche construction theory and biogeomorphology to better understand both.