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The Southern Oregon Land Conservancy is dedicated to saving the places which make our region one of the most biologically interesting places in the world. Working with our partners, we have identified a number of key habitats which deserve permanent protection from human encroachment.
Oak Woodland, Chaparral, and Grasslands
Key habitat types are identified as important due to their role in supporting high biologic diversity and rare or declining plants and animals. In western Oregon and Washington, less than 1% of oak woodland and savanna remains following European settlement.
This endangered habitat, occupying primarily private lands on the valley floor and lower mountain slopes in the Rogue Basin, has been converted to farms, ranches, cities, industrial zones, and residential areas - while fire suppression has interrupted the natural fire frequency, shifting oak woodlands into mixed conifer forests. Invasive non-native plants like Himalayan blackberry and Scot’s broom reduce the survival and growth of oak seedlings as well as other native wildflowers.
In Southern Oregon, the oak savanna complex forms a mosaic of open oak savanna, denser oak woodland, chaparral and meadow. This mix of habitat types is one of the many factors that enhance biodiversity due to the “edge effect.”
The edge effect is an ecological term that describes how the juxtaposition of a variety of habitats increases the tendency to support a greater number of plant and wildlife species. For instance, Gentner’s fritillaria (Fritillaria gentneri), a federally endangered red lily only found in our region, is most often found where oak woodland or chaparral habitats intersect with other habitat types.
In the spring, oak savannas support a beautiful carpet of native wildflowers and provide critical habitat for numerous neotropical songbirds. Large tracts of the oak savanna complex also provide important wildlife corridors offering dispersal through changing climate and connectivity to other protected lands.
The Oregon Department of Fish and Wildlife has identified Strategic Opportunity Areas for important habitats such as oak woodlands. The Klamath-Siskiyou region is one of the most biologically diverse regions in North America, second only to the Appalachian Mountain region.
The Klamath-Siskiyous support an exceedingly high number of plant and animal species. One primary reason for this biodiversity is due to the complex geology of the region including the largest concentration of ultramafic bedrock in North America.
Ultramafic bedrock originates from mantle rock deep in the earth’s crust, including rocks like serpentine and peridotite. Serpentine rocks are green and slippery looking while peridotite is knobby and red to black. Ultramafic means that the rocks are high in iron and magnesium. Soils derived from these rocks weather to a striking red color.
Many rare, threatened, and endangered plants are associated with ultramafic soils such as cobra lily (Darlingtonia californica), Lee’s lewisia, (Lewisia leeana), and Waldo gentian (Gentiana setigera). Some of these rare plants are endemic to the region and grow nowhere else. At least 40 species in Southwest Oregon and Northwest California are considered endemic serpentine plants.
About 11% of federal and state listed rare plants in the Klamath Siskiyou region only grow in ultramafic soils. A number of unique vegetation types, such as Darlingtonia fens, Jeffrey pine savanna, and Port-Orford-cedar riparian areas are also associated with ultramafic soils. Some lands, such as the Jeffrey pine savanna, can often be seen at a distance appearing more barren than surrounding landscapes due to the harsher growing conditions.
Older Forest habitats refer to those areas where trees are large enough to support the variety of species associated with “old growth,” such as spotted owls, red tree voles, Cyperpidium orchids (mountain lady slipper and the clustered lady slipper), and other fauna and flora. Habitat associated with older forests (also called late successional habitat) is often synonymous with northern spotted owl habitat and may refer to those areas commonly used for nesting and roosting.
As with other special habitats, there are far fewer older forests in southwest Oregon than 100 years ago due to logging, development, and wildfire—factors which continue to threaten these areas––especially on private lands. In our region the size of trees used by spotted owls is often much smaller than that used by owls further north in Oregon and Washington.
Home Page Photo Credit: Lee Webb