While human disturbances can destroy ecosystems, new research shows that a little disturbance can be good for forest plants with small ranges. Called endemics, or native plants, these species are often a conservation priority. This is one of the first studies of how human disturbances, even logging, may benefit them. Kessler studied 650 plants that are both relatively common and easy to identify at 16 forest sites in the Bolivian Andes.
Some plants are widespread throughout many ecosystems and some are found only in the Andes.
To his surprise, Kessler found that moderately disturbed forest had more native plant species than the adjacent mature forest. But severely disturbed forest had fewer native plants. The new growth after a clearcut was dominated by bracken ferns and other opportunistic pioneer plants that colonize cleared areas. Human disturbance appears to be good for rare native plants even though they are more vulnerable to invasion by non-native species and do not seem to compete as well as widespread species. Kessler hypothesizes that these native plants, known as endemic species, depend on natural disturbances such as tree falls, flooding and landslides to keep more widespread species from dominating them.