and predators have to adapt to survive. This poses a problem for many animals, for example the Southern Rockhopper Penguins. These penguins are able to live and thrive in a variety of climates due to the penguins' phenotypic plasticity. However, they are predicted to respond by dispersal, not adaptation this time. This is explained due to their long life spans and slow microevolution. Penguins in the subantarctic have very different foraging behavior from those of subtropical waters; it would be very hard to survive by keeping up with the fast changing climate, because these behaviors took years to shape. Dispersal barriers A dispersal barrier may result in a dispersal range of a species much smaller than the species distribution. An artificial example is habitat fragmentation due to human land use. By contrast, natural barriers to dispersal that limit species distribution include mountain ranges and rivers. An example is the separation of the ranges of the two species of chimpanzee by the Congo River. On the other hand, human activities may also expand the dispersal range of a species by providing new dispersal methods (e.g., ballast water from ships). Many such dispersed species become invasive, like rats or stinkbugs, but some species also have a slightly positive effect to human settlers like honeybees and earthworms. Dispersal mechanisms Most animals are capable of locomotion and the basic mechanism of dispersal is movement from one place to another. Locomotion allows the organism to "test" new environments for their suitability, provided they are within the animal's range. Movements are usually guided by inherited behaviors. The formation of barriers to dispersal or gene flow between adjacent areas can isolate populations on either side of the emerging divide. The geographic separation and subsequent genetic isolation of portions of an ancestral population can result in allopatric speciation. Plant dispersal mechanisms Seed dispersal is the movement or transport of seeds away from the parent plant. Plants are limited by vegetative reproduction and consequently rely upon a variety of dispersal vectors to transport their propagules, including both abiotic and biotic vectors. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time. The patterns of seed dispersal are determined in large part by the specific dispersal mechanism, and this has important implications for the demographic and genetic structure of plant populations, as well as migration patterns and species interactions.