The diverse functional roles of over 6,000 species of extant mammals that range in body size across eight orders
of magnitude, from blue whales (Balaenoptera musculus) to tiny Etruscan shrews (Suncus etruscus), contribute
to shaping Earth’s ecosystems. Large mammalian herbivores (e.g., African elephants [Loxodonta africana],
American bison [Bison bison], hippopotamuses [Hippopotamus amphibius]) and carnivores (e.g., wolves [Canis
lupus], pumas [Puma concolor], sea otters [Enhydra lutris]) often have significant effects on primary producers in
terrestrial, aquatic, and marine systems through nutrient cycling, energy flow, and the exertion of bottom-up and
top-down processes. Small mammals, like bats, are important pollinators, dispersers of fruits, and consumers of
arthropods, and others, especially rodents and primates, are important predators and dispersers of seeds. Many of
these mammal-mediated processes occur simultaneously in the same ecosystem, and have significant effects on
community structure of primary producers that in turn alter communities of other vertebrates and invertebrates.
Many mammals also are ecosystem engineers (e.g., elephants, American beavers [Castor canadensis], porcupines
[Erithezon dorsatum], prairie dogs [Cynomys spp.]) that create, significantly modify, or destroy habitat, and by
doing so, they alter ecosystem structure and function and increase habitat heterogeneity and biodiversity. The
extensive influence mammals have on ecosystems results in important services that contribute to human wellbeing,
such as pollination, insect pest control, and bioturbation of soils. The rapid declines in abundance of many
mammal populations and the associated increase in extinction risk raise conservation concerns for mammals.
To maintain mammalian diversity and the critical ecosystem processes they provide, scientists need to mobilize
concern for their status and strive for more effective and comprehensive conservation action. We provide insights
and synthesis on the ecological role of mammals and highlight key research questions and future directions for
their conservation.
Read more: Mammal
