More info for the terms:
competition,
cover,
density,
shrubsOrd's kangaroo rats occur mainly in semiarid, open habitats. In Nevada
they were trapped in desert scrub and gravelly soil, flat pebble desert,
and washes [
8]. In Utah Ord's kangaroo rats have an affinity for open
shrublands and grasslands on sandy soils [
11]. In southeastern Idaho
big sagebrush/crested wheatgrass (Agropyron cristatum) range, most Ord's
kangaroo rat captures occurred on disturbed sites (areas of sparse
cover: Russian-thistle (Salsola kali), cheatgrass (Bromus tectorum),
and green rabbitbrush (Chrysothamnus viscidiflorus), followed by
disturbed areas seeded to crested wheatgrass, then undisturbed big
sagebrush [
17]. In western South Dakota Ord's kangaroo rats are
associated with black-tailed prairie dog (Cynomys ludovicianus) towns
[
34]. In Wyoming Ord's kangaroo rats are abundant in sand dune
communities where vegetation is greater than 10 inches (25 cm) tall and
bare soil exceeds 40 percent [
11]. In Colorado Ord's kangaroo rats were
primarily captured in open areas with firm soil. Firm or lightly
compacted soils are needed for burrow construction; highly compacted
soils are too hard to dig into [
30]. In areas of desert pavement or
tough clay soils in the Trans-Pecos region of Texas, Ord's kangaroo rats
are confined to pockets of windblown sand and alluvial soils along
arroyos [
31].
There is strong intraspecific competition and little interspecific
competition among Dipodomys species [
32]. In New Mexico, where Ord's
kangaroo rats are sympatric with Merriam's kangaroo rats (Dipodomys
merriamii), Ord's kangaroo rats were mostly captured in grassy
microhabitats, and Merriam's kangaroo rats were captured more often
around creosotebush [
32]. Herbicide defoliation of shrubs (for
rangeland improvement) reduced live canopy cover of creosotebush and
resulted in an increase in bush muhly (Muhlenbergia porteri). After
treatment Ord's kangaroo rat replaced Merriam's kangaroo rat as the
dominant rodent. It was suggested that this was due to the change in
habitat structure to open grass [
42].
Removal experiments to establish single species populations of kangaroo
rats were unsuccessful since many kangaroo rats are transient and
quickly occupy vacated habitats [
32]. Only one adult occupies a given
burrow system, except for a brief period during breeding activity.
There is little territoriality above groud except near the burrow
entrance, which is defended [
8].
Home Range: In New Mexico Ord's kangaroo rat annual home ranges in
mesquite averaged 3.35 acres (1.36 ha) [
11]. In Nevada
sagebrush/grassland Ord's kangaroo rat home ranges were estimated to be
1.53 acres (0.62 ha) by the circular method and 1.06 acres (0.43 ha) by
the principal component method. Home range movements increased through
spring and again in late fall and early winter. There was no
significant difference between male and female Ord's kangaroo rat home
ranges; however, female home ranges decreased during reproductive
periods [
26]. Recapture data for Ord's kangaroo rats in Arizona
indicate that they do not travel far from the home range; most Ord's
kangaroo rats were recaptured within 165 feet (50 m) of the original
capture site. Data on the lifetime movements of individuals indicated
that most were recaptured within 330 feet (100 m) of the original
capture site [
6].
Population Density: In sagebrush in the Great Basin, Ord's kangaroo
rats reach an average density of 113 Ord's kangaroo rats per 10 hectares
[
38]. In intermountain salt-desert shrublands Ord's kangaroo rat
population density average 28 individuals per 10 hectares in shadscale
communities and 135 individuals per 10 hectares in black greasewood
(Sarcobatus vermiculatus) communities [
40].