Marc D. Meyer

Vegetation and ecological characteristics of mixed-conifer and Red Fir forests at the Teakettle Experimental Forest

References Anonymous. 1970. Recommendations for an international standard for a mapping method in bird census work.

Historical and current landscape‐scale ponderosa pine and mixed conifer forest structure in the Southern Sierra Nevada

Many managers today are tasked with restoring forests to mitigate the potential for uncharacteristically severe fire. One challenge to this mandate is the lack of large-scale reference information on forest structure prior to impacts from Euro-American settlement. We used a robust 1911 historical dataset that covers a large geographic extent (>10,000 ha) and has unbiased sampling locations to compare past and current forest conditions for ponderosa pine and mixed conifer forests in the southern Sierra Nevada. The 1911 dataset contained records from 18,052 trees in 378 sampled transects, totaling just over 300 ha in transect area. Forest structure was highly variable in 1911 and shrubs were found in 54% of transects. Total tree basal area ranged from 1 to 60 m2 ha−1 and tree density from 2 to 170 ha−1 (based on trees >30 cm dbh). K-means cluster analysis divided transects into four groups: mixed conifer-high basal area (MC High BA), mixed conifer-average basal area (MC Ave BA), mixed conifer-average basal ...

NEST TREES OF NORTHERN FLYING SQUIRRELS IN THE SIERRA NEVADA

Abstract We examined the nest-tree preferences of northern flying squirrels (Glaucomys sabrinus) in an old-growth, mixed-conifer and red fir (Abies magnifica) forest of the southern Sierra Nevada of California. We tracked 27 individuals to 122 nest trees during 3 summers. Flying squirrels selected nest trees that were larger in diameter and taller than either random trees or large (>50-cm diameter at breast height) nearest-neighbor trees. Snags were used more often than live trees relative to their availability. Nest trees were usually close to riparian habitat; 86% of nest trees were <150 m from a perennial creek. Flying squirrels selected red fir and avoided incense cedar (Calocedrus decurrens). Mean distances between nest trees and size of core-nest areas were greater for males than for females. No detectable relationship was found between size of core-nest area and distance to a perennial creek. These results suggest that flying squirrels of the Sierra Nevada may require large trees and snags within 150 m of perennial creeks for their critical habitat needs.

Foraging under multiple costs : the importance of predation, energetic, and assessment error costs to a desert forager

We investigated spatial and temporal variation in the use of resource patches by Chaetodipus penicillatus by documenting changes in foraging activity over several seasons, under two moon phases, and in two resource patch types. In particular, we examined the influence of nocturnal illumination (a surrogate for predation risk) and ambient temperature on: (1) foraging effort (which is inversely proportional to the giving-up density, GUD), and (2) GUD equality, i.e. the ability of foragers to accurately assess patch quality by equalizing heterogeneous resource patches to the same GUD. There were significant positive relationships between foraging effort and relative GUD equality, ambient temperature and foraging effort, and ambient temperature and GUD equality. In contrast, despite having a strong effect at the beginning of our study, moonlight did not have a consistent or significant impact on foraging effort and GUD equality when analyzed over several seasons. Our results indicate that as energetic or predation costs decline, foraging effort rises, which in turn, leads to an increase in GUD equality and a reduction in assessment error costs. This increased harvesting equality is due to both enhanced functional harvest rates and increased accuracy of patch assessment by foragers as more time is spent within a patch. In addition, predation risk and energetic costs appeared to switch in relative importance in C. penicillatus over the course of several seasons. These results emphasize the importance of considering multiple foraging costs and their additive effects in studies of foraging and patch use.

Effects of fire on small mammal communities in frequent-fire forests in California

Fire is a natural, dynamic process that is integral to maintaining ecosystem function. The reintroduction of fire (e.g., prescribed fire, managed wildfire) is a critical management tool for protecting many frequent-fire forests against stand-replacing fires while restoring an essential ecological process. Understanding the effects of fire on forests and wildlife communities is important in natural resource planning efforts. Small mammals are key components of forest food webs and essential to ecosystem function. To investigate the relationship of fire to small mammal assemblages, we live trapped small mammals in 10 burned and 10 unburned forests over 2 years in the central Sierra Nevada, California. Small mammal abundance was higher in unburned forests, largely reflecting the greater proportion of closed-canopy species such as Glaucomys sabrinus in unburned forests. The most abundant species across the entire study area was the highly adaptable generalist species, Peromyscus maniculatus. Species diversity was similar between burned and unburned forests, but burned forests were characterized by greater habitat heterogeneity and higher small mammal species evenness. The use and reintroduction of fire to maintain a matrix of burn severities, including large patches of unburned refugia, creates a heterogeneous and resilient landscape that allows for fire-sensitive species to proliferate and, as such, may help maintain key ecological functions and diverse small mammal assemblages.

EFFECTS OF BURNING AND THINNING ON LODGEPOLE CHIPMUNKS (NEOTAMIAS SPECIOSUS) IN THE SIERRA NEVADA, CALIFORNIA

Abstract Prescribed burning and mechanical thinning are widely used to manage fuels in North American forests, but few studies have examined the relative impacts of these treatments on wildlife. Using a fully factorial and completely randomized design, we examined the short-term effects of prescribed burning (no burn vs. burn), mechanical thinning (no thin, light thin, and heavy thin), and combinations of these treatments on the capture rate and demographic parameters of Lodgepole Chipmunks (Neotamias speciosus) in mixed-conifer forests in the southern Sierra Nevada of California. Chipmunks were sampled in eighteen 4-ha treatment plots during the summer of 1999 and 2000 (pre-treatment) and 2002 and 2003 (post-treatment). Although burning and thinning caused significant changes in forest structure, neither treatment had a significant effect on the capture rate or most demographic parameters of N. speciosus. Body mass of males (2002 and 2003) and the ratio of males to females (2003) decreased following burning. Body mass and percentage reproductive females were positively correlated with the total number of White Fir (Abies concolor) cones produced across treatments and years, possibly reflecting a positive association between chipmunk reproduction and food availability. These results suggest that prescribed burning and mechanical thinning may have minor or no short-term effects on the capture rate and demography of N. speciosus in mixed-conifer forests of the Sierra Nevada, but effects over longer periods have not been investigated.

NEST TREES OF NORTHERN FLYING SQUIRRELS IN YOSEMITE NATIONAL PARK, CALIFORNIA

Abstract We examined nest tree preferences of northern flying squirrels (Glaucomys sabrinus) in an old-growth, mixed-conifer forest of Yosemite National Park, California. We tracked 8 individuals to 21 nest trees during July through September 2004. Flying squirrels selected nest trees that were larger in diameter and taller than either large nearest-neighbor or random trees. Flying squirrels showed no tree species preference, but used snags more often than live trees relative to their availability. Nest trees were not closer to perennial creeks than random trees. Results suggest that northern flying squirrels of Yosemite National Park might require large trees and snags, but unlike more xeric parts of the extreme southern Sierra Nevada, they might not be constrained by proximity to perennial streams.