Humans do not have only a negative impact on grasslands. There are some who do their part to preserve land and restore it. National parks are developed around grasslands and some organizations re-plant areas of depleted grassland. Governments have enacted laws against hunting of endangered animals. In particular, U.S. National Parks Service has preserved land to foster American bison population. While poaching still exists in many areas, there are efforts to stop it.
Humans help in conserving deserts by conserving water — if one conserve water at the place where one lives, there will be more water for dry deserts and by volunteering in a desert by pulling out non-native desert plants.