One obstacle to applying ENMs for predicting past distributions has been that the spatial resolution of modeled LGM climates was coarse, with grid cells typically 50 km or greater; such coarse-resolution climate data smooth over and obscure sharp environmental gradients and narrow barriers to dispersal.
Inflorescences are distinctive, narrow spikes, and seed dispersal is typically passive.
Clines are narrow with respect to dispersal, and there are significant deviations from Hardy-Weinberg equilibrium as well as nonrandom associations (linkage disequilibria) between alleles characteristic of each parental type.
In addition, lower sea levels during the Eocene might also have enhanced the dispersal across narrowed ocean expanses and via additional islands [ 5, 15].
Probably, the aforementioned poor dispersal ability along with a narrow ecological niche trapped C. thomasii in South Italy, by limiting chance to colonize neighboring areas.
Bombina bombina and B. variegata, thought to have diverged during Upper Miocene or Lower Pliocene [3.5 Mya; [ 49- 51]] hybridize in narrow, stable zones maintained by selection and dispersal [ 51].
Hollingsworth et al. (2011) list factors that will work against barcoding success: breeding system, hybridization, polyploidy, long generation times (or reduced mutation rates), narrow taxon concepts, species history and seed dispersal.
For example, cue-dependent cooperation remained stable under most dispersal rates with disassortative mating, a narrow range of dispersal rates with random mating, and was never stable under assortative mating.
They have narrow and linear geographic distributions that may restrict dispersal to a stepping-stone process in species without long-lived planktonic larvae.
