Sagebrush Ecotone

Sagebrush Ecotone

A biome is a distinct biological community that has common characteristics for the environment they live in. Worldwide there are five major biomes – aquatic, desert, tundra, grassland and forest. On a smaller scale, biomes may refer to areas where the predominant vegetation is characterized by adaptations to the particular local environment. For example, Howell’s marsh marigold plants (discussed in my previous post “Howell’s Marsh Marigold” on 12-13-2017)¬† has adapted to live in wet habitats.

An ecotone is a transition area between two biomes where two communities meet and integrate. The boundary between the two communities may be narrow or wide, local or regional. This transition zone results when physical properties, such as soil type, moisture, light and temperature to name a few, undergo a change over a relatively narrow area. Differing species on either side signal an ecotone.

A ecotone is easily visible in a portion of our property that is set aside as a wildlife area (Modoc County CA). There is a small hillock with deep, well-drained soil surrounded by clayey, poorly drained soil. As seen in the photograph, atop the hillock are tall, grey-green sagebrush plants, while the sagebrush plants surrounding the hill are smaller and do not have a greenish color. Near the bottom of the hillock a line separating the two is distinctly visible. That line is a sagebrush ecotone.

The sagebrush atop the hillock is tall sagebrush (Artemisia tridentata) while silver sagebrush (Artemisia cana) surrounds the hill. Tall sagebrush is adapted to deep, well-drained soils while silver sagebrush grows in clayey, poorly drained soil or in standing water. Where the more fertile, drier soil of the hillock changes to wet, less fertile soil of the surrounding area the plant biome changes – a sagebrush ecotone.

Settlers in the 19th Century recognized that the presence of tall sagebrush indicated good agricultural soil and chose the sites for their farms accordingly.

More information about tall and silver sagebrush can be found in my previous posts: “After the Storm” on 09-17-2011 and “Silver Sagebrush” on 12-06-2013.

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Howell’s Marsh Marigold

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Howell’s marsh marigold (Caltha leptosepala) is a “snowbank” flower, blooming early in the season as soon as the snow melts. The buds of this native perennial are produced in the autumn and remain dormant over the winter. Flowering commences once … Continue reading

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Ponderosa Pine Regeneration

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Ponderosa pines (Pinus ponderosa) are considered one of the most fire resistant conifers in the west because of their seedlings’ propensity to benefit from mineral soil seedbeds and open habitats created by wildfires. This fire resistance increases as the tree … Continue reading

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Small Enchanter’s Nightshade

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There is no good explanation for the species name and the common name of small enchanter’s nightshade (Circaea alpina). A native perennial, small enchanter’s nightshade is not related to either the deadly nightshade (Atropa) or the European nightshades (Solanum). So … Continue reading

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Rare Visitor

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In nearly 40 years, Leonard only saw a red crossbill (Loxia curvirostra) on our property one time. That was until last week, when a solitary male crossbill was in the hybrid poplars next to the house along Modoc County Road … Continue reading

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Obligate Hibernation

Yellow Bellied Marmot

Animals exhibit many different types of dormancy. One of them, hibernation, refers to inactivity and metabolic depression associated with low temperatures or food deprivation. Hibernation is characterized by low body temperature, slow breathing and reduced heart rate and a low metabolic rate. Obligate hibernators are animals that hibernate regardless of temperatures or access to food, while facultative hibernation refers to animals that enter hibernation when cold stressed or food deprived, or both. Facultative hibernators enter hibernation in winter, but emerge when the weather is nice. These animals may hibernate and wake several times during a winter.

Yellow bellied marmots (Marmota flaviventris) are examples of obligate hibernation. These rodents hibernate in burrows and dens from approximately September or October and emerge in April or May. They dig their dens under piles of rocks or tangles of tree roots where predators (including man) have a difficult time finding and reaching them. Yellow bellied marmots spend about 60% of their lives hibernating.

Living at higher elevations, yellow bellied marmots prefer a habitat of rock piles in grassy meadows. Emerging from their dens in the spring, yellow bellied marmots are thin. During the summer they feed avidly by day on grasses and other woody and herbaceous meadow vegetation. By fall when the marmot is ready to again hibernate, its body is thickly layered with fat to provide sustenance over the winter.

This yellow bellied marmot was watching Leonard and I from behind some logs along Modoc County CA Road 87 near the Pit River overflow. The opportunity for a good photograph did not present itself, but watching this cute little marmot entertained us for a few minutes.

My other posts about yellow bellied marmots are: “Yellow Bellied Marmot” on 05-13-12 and “Groundhog Day” on 02-01-16.


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Lemmon Ceanothus

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The genus, Ceanothus, has over 45 species in North America. Lemmon¬† ceanothus (Ceanothus lemmonii) is named for John Gill Lemmon (1832 – 1908) who along with his wife, Sara, collected plants throughout the American West for Asa Gray. A native … Continue reading

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