Bi-Modal Semi-Arid Shallow Cool Hills

Description

The community phase pathways for this state were probably similar to State 2. The only difference between States 1 and 2 is the assumption that non-native species were absent from State 1. The widespread presence of non-native annual species makes a reference state devoid of these species unrealistic. Although some areas, at times may seem to be in reference condition, non-native annuals are likely to be present at some times of year and/or following certain years with the right combination of precipitation amounts, timing and temperatures.

Description

Non-native annuals, including red brome (Bromus rubens) and red-stem storks bill (Erodium cicutarium) are naturalized in this state. Their abundance varies with precipitation but they are, at a minimum, sparsely present. Non-native annuals may be present in current year's growth or in the soil seedbank. This ecological state has a long history of livestock grazing which is likely to have obscured our understanding of state and community pathways as well as vegetation composition. Given that this ecological site is at higher elevations and can support perennial bunch grasses, unlike the more harsh and arid Mojave Desert environments, this ecological site would have been attractive to early livestock operations in the Mojave Desert.

Submodel

Description

This state exists when blackbrush is lost from the community as a result of large-scale and high intensity fires, where blackbrush seed source is not available to recolonize, and/or recurrent fire does not provide intervals long enough for blackbrush recovery. Evidence suggests that Indigenous land management practices were employed in and around this ecological site for several reasons, which include increasing the number of individual Mojave yucca (Yucca schidigera) and banana yucca (Yucca baccata) plants.

Several bands of Chemehuevi (Hokwaits, Kauyaichits, and the Timpashauwagotsits) spent time in and around the Providence and New York Mountains and are reported to have employed fire as a hunting technique to capture rabbits and deer (Miller and Miller 1967). Laird (1984) also describes Chemehuevi tales where fire was used to improve the growth and quality of basketry materials as well as to char seeds to be eaten.

Whether intentional or not, the greatest differences recorded between pre- and post-fire vegetation demographics, aside from the blackbrush removal, is an increase in Yucca schidigera and Yucca baccata individuals. S.R. Abella (2009) found Mojave yucca (Yucca schidigera) to exhibit the highest post-fire sprouting rate than any other plant species in a study of post-fire recovery in the Mojave and Sonoran Deserts. Abella et al (2009) also described vigorous Yucca baccata and schidigera resprouting following a Mojave Desert burn. In yet another study of post-fire effects, a similar yucca (Yucca glauca) increased the number of rosettes, from pre-burn, by 17% two years following the experimental fire (Parmenter 2008). Many tribes such as the Chemehuevi used Yucca species for food, soap, baskets, bowstrings, sandals and many other items (Bean and Saubel 1972).