<p>Some muroid rodents may be essential ("keystone") species in maintaining the health of forests, through their role in spreading mycorrhizal fungi or dispersing seeds. Others affect the rate of forest succession by preying on tree seedlings. Some species are important pollinators. Others dig tunnels, and in doing so, create habitat for other species and aerate the soil. Many species are a vital food source for a wide range of predators, and muroids as a group support many different kinds of parasites, such as <span class="taxon">acari</span>, <span class="taxon">siphonaptera</span>, <span class="taxon">anoplura</span>, <span class="taxon">sarcophagidae</span>, <span class="taxon">nematoda</span>, <span class="taxon">Cestoda</span>, and trypanosomes. Finally, a few muroid species are commensal with humans, inhabiting cities and towns and relying on human-produced waste to survive.<span> (Johnson, Pauw, and Midgley, 2001; Manson, Ostfeld, and Canham, 2001; Roberts, Janovy, and Jr, 2000; Zhang, Zhang, and Liu, 2003)</span></p>  <p><strong>Ecosystem Impact: </strong>Disperses seeds; Pollinates; Creates habitat; Soil aeration; Keystone species</p>