Treesearch

Differences in hydrologic response across the rain-snow transition in the southern Sierra Nevada were studied in eight headwater catchments – the Kings River Experimental Watersheds – using continuous precipitation, snowpack, and streamflow measurements. The annual runoff ratio (discharge divided by precipitation) increased about 0.1 per 300 m of mean catchment elevation over the range 1,800-2,400 m. Higher-elevation catchments have lower vegetation density, shallow soils with rapid permeability, and a shorter growing season when compared with those at lower elevations. Average annual...

Processes controlling streamflow generation were determined using geochemical tracers for water years 2004–2007 at eight headwater catchments at the Kings River Experimental Watersheds in southern Sierra Nevada. Four catchments are snowdominated, and four receive a mix of rain and snow. Results of diagnostic tools of mixing models indicate that Ca2+, Mg2+, K+ and Cl- behaved conservatively in the streamflow at all catchments, reflecting mixing of three endmembers. Using endmember mixing analysis, the endmembers were determined to be snowmelt runoff (including rain on snow), subsurface flow...

This paper addresses the effects of gaseous nitric acid (HNO3) and ozone (O3), two important air pollutants, on six lichen species with different morphological, ecological, and biological characteristics. The treatment chambers were set up in a factorial design consisting of control chambers, chambers fumigated with HNO3, with O3, and with HNO3 and O3, together. Each species showed a different sensitivity to the fumigations, reflecting the physiological variation among species. Our results clearly indicate that HNO3 is a strong phytotoxin to many lichens, and that O3 alone has little...

For over a century, white pine blister rust (WPBR), caused by the introduced fungal pathogen, Cronartium ribicola J.C. Fisch., has affected white pine (Subgenus Strobus) individuals, populations, and associated forest communities in North America. We surveyed eight populations of whitebark pine (Pinus albicaulis Engelm.) across a range of environmental conditions in subalpine forests of the Lake Tahoe Basin, California and Nevada, to determine how WPBR is influencing host fecundity (i.e., female cone production and recruitment), survival, and current population trends. In this region and...

The management of second growth forests to accelerate the restoration of late-successional and old growth characteristics will be one of the greatest challenges for conservation in the redwood region over the next century. In the redwood region, the largest complex of protected areas exists in the north, however >50 percent of these forest reserves are composed of logged, degraded second growth forests. Strategic restoration actions have the potential to accelerate the restoration of old growth forest characteristics and the old growth forest species assemblage that requires these features....

Bats are known to roost in redwood forests year-round, but their activities outside the summer season are poorly understood. To improve understanding of the use of redwoods by resident and migrant bats, we conducted 74 mist net surveys between February 2008 and October 2010. Captures were dominated by Yuma myotis (M. yumanensis) in the summer and silver-haired bats (Lasionycteris noctivagans) in the winter. During November-February, silverhaired bats, accounted for 78 percent of 23 captures and male:female sex ratio was (9:9). By contrast, during June-August, silver-haired bats accounted...

Since 2005, a life cycle monitoring project in Pudding Creek, California, has utilized a variety of methodologies including an adult trap, spawning surveys, PIT tags, electro-fishing, and a smolt trap to estimate coho salmon adult escapement, juvenile abundance, juvenile growth, winter survival, and marine survival. Adult coho salmon escapement and smolt abundance are closely related when spawner abundance is high. However, with decreasing escapement, smolt abundance appears to stabilize. Adult abundance has declined dramatically, from 1200 in 2005 to 20 in 2010. Corresponding smolt...

Following the Cedar Fire (one of seven large wildfires that burned in southern California during the autumn of 2003), aerial hydromulch was applied at 50 and 100% cover to reduce hillslope erosion in chaparral shrublands. Our objectives were to determine the effectiveness of hydromulch in preventing erosion, and to see if plant recovery was hindered by treatment. We installed 54 silt fences to measure sediment production. Five 1-m2 grids were placed behind each fence to measure plant recovery. Hydromulch was effective in reducing erosion immediately after the fire; however, its benefits...

The Sonoma Tree Vole (Arborimus pomo) – a small arboreal mammal associated with mature forests – is a California Species of Special Concern due to concerns regarding loss of habitat from harvest, fire, and conversion. By counting their nests, we examined A. pomo use of pole to mature forest seral stages from 2001 to 2005 using line transects at 64 study sites distributed across redwood (Sequoia sempervirens), mixed conifer, Douglas-fir (Pseudotsuga menziesii/), and hardwood dominated stands. A total of 441 nests were found including 215 active and 226 inactive nests. The highest percentage...

Surveys for northern spotted owls on Green Diamond Resource Company's (formerly Simpson Timber Company) ownership in coastal northern California were initiated in 1989. The following year, a long-term demography study was initiated that has continued to the present time. A Habitat Conservation Plan was developed for the species in 1992 and numerous habitat studies followed. The extensive dataset generated was used to estimate the trend in owl numbers, develop resource selection functions for nighttime activity and nesting habitat, and analyze the factors influencing spotted owl survival,...