Although much of Craters of the Moon is covered by young lava flows, it supports a surprising diversity of plant communities. Uniquely adapted plants and a variety of abundant vegetation can be found here.
Over 750 different types of plants (taxa) have been identified in the park. Vegetation in different successional stages can be found on lava flows, in cinder areas, on kipukas, and in mountain and riparian areas. Many unique plants have developed ways to adapt and to survive the extreme conditions they face here.
The types and density of vegetation vary considerably and depend on such factors as geology, availability of soil and water, aspect, air temperature, and exposure to wind. The density of vegetation on lava flows depends primarily on the amount of soil available. Although lava flow surfaces support only lichens, vascular plants are able to grow in depressions on those surfaces. When basalt rock is very young, the only soil available is whatever blows into cracks and fractures. As soil develops within these cracks over time, vegetation can begin to grow. The depth of crevices, cracks, and depressions fixes the amount of soil and moisture that can be held. The size of the crack also determines the types of plants that will grow and what degree of protection they will have from harsh climactic conditions, such as extreme air temperatures and exposure to high winds.
Cinder cones support three different plant communities: cinder garden, shrub, and limber pine and/or juniper trees. These communities are determined primarily by aspect and by succession. In the early stages of succession, cinder gardens are colonized by species that produce spectacular spring wildflower displays. As soils develop on the cinders, antelope bitterbrush (Purshia tridentata) dominates shrub communities. And on the north-facing slopes where sufficient moisture is available, limber pine trees (Pinus flexilis) and/or juniper trees (Juniperus spp.) dominate.
Kipukas are islands of native vegetation that have developed on old lava flows surrounded by newer flows. Some kipukas in the monument have been protected from alteration by areas of rough lava and represent rare examples of undisturbed shrub steppe habitats. Dominant kipuka vegetation includes sagebrush and grasses.
The portion of the monument north of US Highway 20/26/93 is characterized by mountain and riparian areas that contain three vegetative types absent from the rest of the monument: Douglas-fir/mountain snowberry (Symphoricarpos oreophilus), upland quaking aspen, and riparian. The three types cover only a small percentage of the monument, but they provide critical wildlife habitat. The Douglas-fir forest (Pseudotsuga menziesii) is found on relatively steep, north-facing slopes of older cinder cones and along Little Cottonwood Canyon. The quaking aspen groves (Populis tremuloides) are in upland sites away from permanent stream courses. Riparian zones occur along creeks in drainages and are characterized by dense woody and herbaceous vegetation.
Many species of grass are found among the sagebrush of southern Idaho.
Species Attribute Definitions
Occurrence values are defined below. One or more Occurrence Tags may be associated with each Occurrence value.
Present: Species occurs in park; current, reliable evidence available.
Probably Present: High confidence species occurs in park but current, verified evidence needed.
Unconfirmed: Species is attributed to park but evidence is weak or absent.
Not In Park: Species is not known to occur in park.
Adjacent: Species is known to occur in areas near to or contiguous with park boundaries.
False Report: Species was reported to occur within the park, but current evidence indicates the report was based on misidentification, a taxonomic concept no longer accepted, or other similar problem of error or interpretation.
Historical: Species' historical occurrence in park is documented. Assigned based on judgment as opposed to determination based on age of the most recent evidence.
Animals: May be seen daily, in suitable habitat and season, and counted in relatively large numbers.
Plants: Large number of individuals; wide ecological amplitude or occurring in habitats covering a large portion of the park.
Animals: May be seen daily, in suitable habitat and season, but not in large numbers.
Plants: Large numbers of individuals predictably occurring in commonly encountered habitats but not those covering a large portion of the park.
Animals: Likely to be seen monthly in appropriate habitat and season. May be locally common.
Plants: Few to moderate numbers of individuals; occurring either sporadically in commonly encountered habitats or in uncommon habitats.
Animals: Present, but usually seen only a few times each year.
Plants: Few individuals, usually restricted to small areas of rare habitat.
Animals: Occurs in the park at least once every few years, varying in numbers, but not necessarily every year.
Plants: Abundance variable from year to year (e.g., desert plants).
Unknown: Abundance unknown
Native: Species naturally occurs in park or region.
Non-native: Species occurs on park lands as a result of deliberate or accidental human activities.
Unknown: Nativeness status is unknown or ambiguous.
The Checklist contains only those species that are designated as "present" or "probably present" in the park.
The Full List includes all the checklist species in addition to species that are unconfirmed, historically detected, or incorrectly reported as being found in the park. The full list also contains species that are "in review" because their status in the park hasn't been fully determined. Additional details about the status of each species is included in the full list.
The checklist will almost always contain fewer species than the full list.