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Desiccation Sensitivity And Heat Tolerance Of Prunus Ilicifolia Seeds Dispersed By American Black Bears (Ursus Americanus), Mark Borchert, Claudia M. Tyler
Desiccation Sensitivity And Heat Tolerance Of Prunus Ilicifolia Seeds Dispersed By American Black Bears (Ursus Americanus), Mark Borchert, Claudia M. Tyler
Western North American Naturalist
Carnivore consumption of fruit is a principle means by which many fleshy-fruited plant species achieve long-distance seed dispersal. We examined carnivore dispersal of hollyleaf cherry (Prunus ilicifolia) seeds, specifically assessing the survival, desiccation sensitivity, and germination of seeds found in bear scats. Studies were conducted both in the laboratory and in 2 burn areas in Los Padres National Forest, California. Bear scats containing P. ilicifolia seeds were collected in burned and unburned chaparral. We counted seeds in each scat and noted whether endocarps had tooth punctures or rattled audibly when shaken. For comparative germination trials, we also collected …
Rabbit Abundance Relative To Rainfall And Plant Production In Northern Chihuahuan Desert Grassland And Shrubland Habitats, David C. Lightfoot, Ana D. Davidson, Christopher M. Mcglone, Dara G. Parker
Rabbit Abundance Relative To Rainfall And Plant Production In Northern Chihuahuan Desert Grassland And Shrubland Habitats, David C. Lightfoot, Ana D. Davidson, Christopher M. Mcglone, Dara G. Parker
Western North American Naturalist
No abstract provided.
Nesting Ecology Of Yellow Warblers (Dendroica Petechia) In Montane Chaparral Habitat In The Northern Sierra Nevada, Diana L. Humple, Ryan D. Burnett
Nesting Ecology Of Yellow Warblers (Dendroica Petechia) In Montane Chaparral Habitat In The Northern Sierra Nevada, Diana L. Humple, Ryan D. Burnett
Western North American Naturalist
The Yellow Warbler (Dendroica petechia) is considered a riparian specialist in much of western North America, but in California it also breeds in a second habitat type: montane chaparral of the Sierra Nevada and southern Cascades. We monitored Yellow Warbler nests in montane chaparral and assessed their poorly known nesting ecology in this habitat. We also conducted point counts in upland habitat throughout the region. We determined habitat associations for Yellow Warblers based on nest site and point-count vegetation data; nests were predominantly in bush chinquapin (Chrysolepis sempervirens) and greenleaf manzanita (Arctostaphylos patula), and …
A Late-Pleistocene/Holocene Biotic Community From Marmot End Alcove, Escalante River Basin, Colorado Plateau, Usa, Manny Kropf
A Late-Pleistocene/Holocene Biotic Community From Marmot End Alcove, Escalante River Basin, Colorado Plateau, Usa, Manny Kropf
Western North American Naturalist
Skeletal remains of the extinct mountain goat Oreamnos harringtoni and Marmota (marmot), an extralimital species, were recovered from Marmot End Alcove along with remains of montane plants that included Pseudotsuga menziesii (Douglas-fir), Picea (spruce), Pinus flexilis (limber pine), and Juniperus communis (common juniper). The alcove is located in Harris Wash, a semiarid tributary in an unstudied portion of the Escalante River Basin on the Colorado Plateau in southern Utah. A Marmota incisor tooth and montane plant needles returned late Pleistocene AMS dates ranging from 12,300 yr BP to 15,600 yr BP.
Present Effects Of Past Wildfires On Leaf Litter Breakdown In Stream Ecosystems, Peter Koetsier, Teresa R. B. Krause, Quenton M. Tuckett
Present Effects Of Past Wildfires On Leaf Litter Breakdown In Stream Ecosystems, Peter Koetsier, Teresa R. B. Krause, Quenton M. Tuckett
Western North American Naturalist
We investigated the present effects from a 10-year-old wildfire on leaf litter breakdown rates in 3 headwater streams in central Idaho. These systems experienced a massive debris flow one year after the fire. Based on soil instability and burn patterns, we identified 3 stream conditions: unburned, burned only, and burned/scoured. We placed leaf bags containing willow leaves (Salix sp.) in each stream type and removed bags at various time intervals until all bags were collected 100 days after their introduction. Leaf material was dried and weighed, and decay rate coefficients were calculated. Macroinvertebrates colonizing the bags were enumerated and …
Pollen Evidence Of Historical Forest Disturbance On The Wasatch Plateau, Utah, Jesse L. Morris, Andrea R. Brunelle, A. Steven Munson
Pollen Evidence Of Historical Forest Disturbance On The Wasatch Plateau, Utah, Jesse L. Morris, Andrea R. Brunelle, A. Steven Munson
Western North American Naturalist
Environmental indicators from lake sediments provide excellent opportunities to improve understanding of forest disturbance processes and corresponding changes in forest composition. Our research provides a methodology for assessing recent, historic, and prehistoric disturbances using lacustrine sediment records. We collected sediment cores from Blue Lake, a small subalpine lake on the Wasatch Plateau in central Utah. These cores record environmental changes caused by both spruce beetle (Dendroctonus rufipennis Kirby) and human (logging and livestock grazing) modification. We observed deteriorated insect remains in the lake sediments. These remains correspond temporally with a historic spruce beetle outbreak, though alkaline conditions in the …
Large-Scale Effects On Bird Assemblages In Desert Grasslands, Giselle Block, Michael L. Morrison
Large-Scale Effects On Bird Assemblages In Desert Grasslands, Giselle Block, Michael L. Morrison
Western North American Naturalist
During winter 1996–1997 and summer 1997, we surveyed birds at 26 study sites in desert grasslands of Arizona and New Mexico to determine tolerance of birds to variability in plant composition and structure. The relationship between bird abundance and vegetative characteristics might be an important consideration in the development of management and restoration plans. Of the 49 bird species we observed, we examined 13 and 16 species in detail for winter and summer seasons, respectively. A noticeable shift in species composition occurred between 3% and 10% woody plant cover. During winter, Chestnut-collared Longspurs (Calcarius ornatus) and Horned Larks …