Kangaroo rats: ecosystem engineers on western rangelands

Authors: Longland, William - Bill; DIMITRI, LINDSAY - University Of Nevada

Submitted to: Rangelands
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2020
Publication Date: 6/15/2021
Citation: Longland, W.S., Dimitri, L. 2021. Kangaroo rats: ecosystem engineers on western rangelands. Rangelands. 43(2):72-80. https://doi.org/10.1016/j.rala.2020.10.004.
DOI: https://doi.org/10.1016/j.rala.2020.10.004

Interpretive Summary: There are at least 20 species of kangaroo rats found throughout arid western rangelands of North America. Kangaroo rats are not only unique to western North America, they are unique among rodents in appearance and in various adaptations for desert living. As their name implies, these animals hop on their hind legs like true kangaroos. Kangaroo rats do not need to drink water, but get sufficient water from a diet composed largely of seeds and from metabolizing their food. They are also uniquely adapted for escaping attacks from their primary predators – owls and snakes – which they detect with specialized hearing and evade with gymnastic-like leaps. Kangaroo rats are considered as “ecosystem engineers,” because their activities have major effects on both plant and animal communities in arid environments. For example, new seedlings of certain plant species are produced mainly from seed caches made by kangaroo rats, and the presence of kangaroo rats influences the presence of other animal species in the local community. Several species of kangaroo rats have very restricted ranges and have become quite rare, with some of them now listed as federally endangered. The future of these ecosystem engineers depends on conservation efforts in the face of challenges posed by vanishing habitat and climate change.

Technical Abstract: Kangaroo rats are a group of 20 or more bipedal rodent species in the genus Dipodomys found exclusively in North America, where they occur primarily in deserts and other arid environments in the west, and often function as keystone species due to their major effects on these environments. These rodents are uniquely adapted to arid habitats; they can exist on a diet composed largely of seeds without drinking free water. Because arid habitats are generally open with reduced vegetative cover for protection, kangaroo rats also exhibit specialized adaptations for avoiding predation – especially threats from owls and snakes. They evade attacks from these predators using gymnastic-like leaps and maneuvers within milliseconds of being captured. Kangaroo rat activities, such as digging, altering the composition of soil seed banks through their foraging, and storing seeds in shallowly-buried surface caches, account for the keystone species or ecosystem engineer status of these rodents. These activities can have major effects on local plant and animal communities. Although some kangaroo rat species are quite common and occur over large geographic areas, several species have very limited ranges. Some species with limited distributions as well as some subspecies of otherwise common species have become very rare and are listed as endangered. Most of these occur in California and in Baja, Mexico. The ecological importance of kangaroo rats as keystone species as well as their uniqueness are strong arguments for ongoing conservation efforts aimed at rescuing imperiled populations. Threats to these animals and the fragile arid systems they occupy from climate change will only make future conservation of kangaroo rats even more of a challenge.