             
 The LUHNA Book!
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The Palouse bioregion encompasses the rolling, fertile hills of the Palouse prairie, as well as the more southerly Camas Prairie and the forested hills and canyonlands of the area's rivers. 
The Palouse Prairie lies at the eastern edge of the Palouse bioregion, nroth of the Clearwater River. Once an extensive prairie composed of mid-length perennial grasses such as bluebunch wheatgrass (Agropyron spicatum) and Idaho fescue (Festuca idahoensis), today virtually all of the Palouse Prairie is planted in agricultural crops. The native prairie is one of the most endangered ecosystems in the United States (Noss et al. 1995), as only a little over one percent of the original prairie still exists.
The peculiar and picturesque silt dunes which characterize the Palouse Prairie
were formed during the ice ages (Alt and Hyndman 1989). Blown in from the
glacial outwash plains to the west and south, the Palouse hills consist of
more or less random humps and hollows. The steepest slopes, which may reach
50% slope, face the northeast. The highly productive loess ranges from 5
to 130 cm deep (Williams 1991). Large areas of level land are rare.
Higher elevations bordering the prairies such as the Palouse Range support an often dense coniferous forest. 
Image within the watershed level detailed analysis area within the Viola Quadrangle (USGS 7.5' map). 
Farming was extremely labor-intensive and still relied heavily on human and horse-power. An organized harvesting/threshing team in the 1920's required 120 men and 320 mules and horses (Williams 1991). Teams moved from farm to farm as the crops ripened. Few farmers had enough horses to pull such a machine, which required a crew of 40 horses and six men to operate on level ground. Because of this, use of combines on the Palouse lagged behind use in other farming communities in the United States. 
It was only when the Idaho Harvester Company in Moscow began to manufacture a smaller machine that combine harvesting became feasible. By 1930, 90% of all Palouse wheat was harvested using combines (Williams 1991). 
The next step in mechanization was development of the tractor. As with the combines, the first steam engine and gasoline-powered tractors were too heavy and awkward for use on the steep Palouse hills. The smaller, general use tractors introduced in the 1920s were only marginally used. As late as 1930, only 20% of Palouse farmers used tractors (Williams 1991). 
People have taken their toll on wildlife. Once abundant birds and small mammals are few. The intensive roadbed-to-roadbed farming practiced today across the Palouse leaves few fences and fewer fencerows. Many once intermittent streams are farmed; many perennial streams with large wet meadows adjacent to them are now intermittent or deeply incised. 
Riparian areas offer breeding habitat for a greater diversity of birds than any other habitat in the u.S. (Ratti and Scott 1991). Loss of woody vegetation - trees and shrubs - along stream corridors means fewer birds and eventually fewer species. The majority of riparian areas have been lost across the bioregion. 
Lately, conversion of agricultural lands to suburban homesites on large plots invites a new suite of biodiversity onto the Palouse Prairie. University of Idaho wildlife professor J. Ratti has documented changes in bird community composition over the past 10 years as he converted a wheat field into a suburban wildlife refuge. His 6 ha yard now attracts 86 species of birds, an increase from 18. 
Intensification of agriculture has affected both water quantity and quality. Agriculture has changed the bydrograph, increasing peak runoff flows and shortening the length of runoff. The result is more intense erosion and loss of perennial prairie streams. As early as the 1930s soil scientists were noting significant downcutting of regional rivers (Victor 1935) and expansion of channel width. Higher faster runoff caused steams to downcut quickly, effectively lowering the water table in immediately adjacent meadows. On the South Palouse River, this process was so efficient that by 1900 farming was possible where it had been too wet previously (Victor 1935). Replacement of perennial grasses with annual crops resulted in more overland flow and less infiltration, which translates at a watershed level to higher peak flows that subside more quickly than in the past. Once perennial prairie streams are now often dry by mid-summer. This has undoubtedly influenced the amphibious and aquatic species. 
Population size in Latah and Lewis counties, Idaho and Whitman county, Washington 1900 - 1990.
As population grew, towns and cities appeared changing the complexion of
the area. By 1910, there were 22,000 people scattered in 30 communities
across the Palouse Prairie.
Within our fine-scale analysis area, 170 ha (7% of the total area) were converted to agriculture between 1940 and 1965, mostly from open shrublands and riparian areas. Most forest lands were logged during this period creating open forests with many shrubs. 
Average size farm in Latah and Lewis counties, Idaho and Whitman county, Washington, 1900 - 1992. 
Percent change in rural population in Latah and Lewis counties, Idaho and Whitman county, Washington 1900 - 1990. 
Residency of landowners near Viola, Idaho by distance from property, 1940 - 1992. 
Wheat production in the counties of the Palouse Bioregion, 1929 - 1992.
Crop production increased dramatically (200 - 400%) after the introduction
of fertilizer following World War II.
Acres on which fertilizer is used as percentage of total acres farmed in counties of the Palouse Bioregion.
Crop production increased dramatically (200 - 400%) after the introduction
of fertilizer following World War II.
Change in vegetation for the Palouse Bioregion, pre-settlement to present.
We used a broad-scale analysis to monitor changes in grass, shrubs, or
forest cover types. Since 1900, 94% of the grasslands and 97% of the
wetlands in the Palouse Bioregion have been converted to crop, hay, or
pasture lands. Approximately 63% of the lands in forest cover in
1900 are still forested, 9% are grass, and 7% are regenerating
forestlands or shrublands. The remaining 21% of previously forested lands
have been converted to agriculture or urban areas.
Changes in major vegetation types for four sections of the Viola quandrangle, 1940 - 1989.
We initiated our finer-scale analysis to identify probable locations and
extents of habitats under-represented at the broad scale, particularly
haylands, riparian areas and shrubfields. In our four-section analysis
area, small habitat patches have declined, particularly between 1940 and
1965. Stringers of riparian vegetation have shrunk to thin, broken tendrils
and shrub lands have virtually disappeared. Although this analysis reveals
potentially significant trends, it is unknown how well this area represents
the Palouse Prairie as a whole. Additional studies would be needed to
verify this analysis.
Distribution of Yellowstar thistle and common crupina in the Idaho part of the Palouse Bioregion.
The impacts of domestic grazers on the grasslands of the Palouse and
Camas Prairies was transitory because much of the areas were rapidly
converted to agriculture. However, the canyonlands of the Snake and
Clearwater Rivers and their tributaries with their much shallower
soils, steep topography, nad hotter, drier climate, were largely
unsuitable for crop production and were consequently used for a
much longer period by grazing domestic animals (Tisdale 1986). There,
intense grazing and other disturbances have resulted in irreversible
changes with the native grasses largely replaced by annual grasses of
the genus Bromus and noxious weeds, particularly from the genus
Centaurea. The highly competitive plants of both of these genera
evolved under similar climatic regimes in Eurasia and were introduced to
the U.S. in the late 1800s.
Existing and historical fire regimes in the Palouse Bioregion.
While there is some debate over how frequently the Palouse prairie burned
historically, there is consensus that fires are generally les frequent
today than in the past, primarily due to fire suppression, construction of
roads (which serve as barriers to fire spread) and conversion of grass and
forests to cropland (Morgan et al. 1996). Historians recount
lightning-ignited fires burning in the pine fringes bordering the prairies
in late autumn, but the extent to which forest fires spread into the prairie
or the converse is not known. Some fire ecologists believe the Nez Perce
burned the Palouse and Camus Prairies to encourage growth of Camas
(Morgan, pers. Comm); but there is little historical record to solve the
mystery. European-American settlers used fire to clear land for settlement
and grazing until the 1930s. Since then, forest fires have become less
common. One result ha been increasing tree density on forested lands and
encroachment of shrubs and trees into previously open areas. Consequently,
when fires occur in the forest, they are more likely to result in mixed
severity or stand replacing events.
Critical wildlife habitat and vertebrate species richness in Latah county.
Information obrained in this study is being used to assist the Latah County
Planning Commission develop new building and sub-division regulations for
the rural areas of the county. Data developed and analyzed are useful in
identifying which habitats are most critical to protect, where conservation
of soil, water and open space resources is most critical, and where and how
restoration efforts might be most effective. Data and understanding of
changes in vegetation and land use are being used to develop maps of
critical wildlife habitats.
The maps of critical wildlife habitats are the basis for defining "Natural Resource Protection Districts", each of which has a set of regulations pertaining to housing density and stream crossings. They also outline priorities for mitigation through conservation easement set asides.
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