Dispersal-range size moderators in animals vs. plants
Our results confirmed our hypothesis that a positive dispersal-range
size relationship is less common for endotherms than for ectotherms
(Table 1, Fig. 3, Table S2 Supple. Mat.), possibly because endotherms
are less affected by niche limitation than ectotherms due to broad
thermal tolerances, allowing them to attain and persist in larger ranges
more easily. Indeed, the ‘thermal plasticity hypothesis’ proposes that
high metabolic rates increase thermal tolerance, and the ‘energy
constraint hypothesis’ that due to higher and sustained levels of energy
requirements, organisms with high metabolic rates need to forage farther
and with lower densities, resulting in larger home ranges and range
sizes (Pie et al. 2021). Even though endo- and ectotherms might not
differ in the dispersal capacities required during the transfer phase of
dispersal, endothermy might have an advantage during settlement and
establishment (the third phase of dispersal). If endothermy has allowed
species to attain range sizes that are larger than predicted by their
dispersal ability only, this might explain why we find fewer positive
relationships between dispersal and range size. Note that a model
including latitude instead of temperature regulation has a similarly
good model fit (Table S1, S2 Suppl. Mat).