Vegetation Change in the Santa Rosa Mountains: A Repeat Photography Study by Brad Schultz, Extension Educator, University of Nevada Cooperative Extension, Winnemucca, NV Background: Repeat photography can qualitatively document vegetation changes at large scales. For those involved in discussions about the “condition” or “state” of rangelands today, there is great benefit for understanding what the composition and structure of those rangelands was shortly after settlement: an era of unmanaged grazing that exemplified the tragedy of the commons. The Forest Service’s Santa Rosa Ranger District (hereafter District), in north-central Humboldt County, is one area with a photographic history of over 100 years. The District has about 288,000 acres in active grazing allotments. Willow laced small streams, wet and dry meadows, and stands of aspen are common, and interspaced with mountain big sagebrush, mountain brush and low sagebrush plant communities. Livestock grazing began in the 1860’s, but use was poorly documented until 1906-1910 era, when 150,000 to 200,000 head of sheep, 16,000 head of cattle, and about 1,500 domestic horses grazed the District each year (Figure 1).
This equated to about one million head months per year, or about 5.4 months per head, per year, on the District. This resulted in continuous grazing from when plant growth began each spring until the stock moved to other areas in the fall. In 1912, the District implemented a permit system. Livestock numbers declined from about 200,000 to 81,000 head, mostly through elimination of the nomadic sheep herds, but also 2,500 fewer cattle. Even with dramatically fewer numbers, livestock grazing remained season-long until at least the late 1940’s. The District had only three or four grazing allotments, with no internal pastures, and no infrastructure to adequately implement rotation grazing systems. Sheep permits were converted to cattle or being phased out. The implementation of rotational grazing systems began in the late 1940’s, as did the construction of associated infrastructure (fences, water developments,etc.).Full implementation and enforcement of rotation systems across the entire District probably did
not occur until the 1960-1970 era, with periodic adjustments since then. The last sheep permit ended in 1963. Deer populations from the 1950s into the 1980s were much larger than today, Today, livestock grazing occurs in 12 active allotments with 58 pastures. Each allotment follows either a rest-rotation or deferred rotation system, with two to seven pasture per allotment. Turn-on dates range from mid-April to midJune, and off-dates from late August to the end of September. The current permits total about 10,542 head of cattle and a couple dozen domestic horses. This equates to about 36,500 permitted head months or 3.6 percent of those in 1910. Each head now spends and average of 3.6 months on the District, which is 65% of the annual duration in 1910. Since 1970, livestock numbers have changed little, and the District has built several large riparian pastures since 1990. District wide management changes from 1912 through the 1960’s have given way to periodic adjustments that typically address site specific issues.
Methods and Work to Date: In about 2015 the USFS provided Brad Schultz, Extension Educator in Winnemucca, NV thousands of historical photos from the District. Some were from the 1910-1930s era, but most from the 1950’ through the early 1990’s. Those with distinct topographic features to facilitate their relocation were extracted for potential use. Repeat photography works best when the past and current photos occur at the same growth stage, time of day, and sunlight. Since 2015 smoke-filled skies often have precluded replicating the conditions of the original photos. In 2020 and 2021, repeat photos occurred whenever skies were clear of smoke, following the concept that any current photo is more useful than no photo, for understanding changes in rangeland landscapes. For all repeat photos, topographic features were realigned to the extent possible. The photo-point of the new photo was recorded with a handheld GPS unit, to facilitate future efforts of photo documentation. To date, about 150 repeat photos have been obtained, but space only allows presentation of a few in this article. Results and Discussion: The historic photos occur across a suite of vegetation types ranging from upland shrub-grass range, to aspen stands, to wet and dry meadows. Pictures from the 1910 era show widespread severe degradation (Photos a in Figures 2-4), which often persisted into the 1960’s and later (Figure 2b, 2c, 5a, and 6a).
Forest Reserve was established in 1911. Figure 1. The change in head months per year on the Santa Rosa Ranger District since 1906. Head month numbers remained near one million through at least 1910 or 1911, before being cut 57 percent in 1913. Head months have remained almost constant since about 1970, and have declined about 14,000 since 1960. 30 MARCH 2022
The Progressive Rancher
The photo record clearly demonstrates that only cutting livestock numbers was not a viable solution to the historic grazing problems on the District. Head months on the District in 1945 and later were only five percent or less of those in 1910, but severely degraded range persisted for several decades or more. Many stands of aspen only began to establish an understory in the early 1960s (Figures 2b and 2c).
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