Number and condition of seeds in ponderosa pine cones in central Arizona

Ponderosa pine cones from 10 areas in Arizona were collected prior to natural seed dispersal and dissected to determine the number of sound, hollow, and insect-damaged seeds in each cone. Total and sound seed yields per cone did not vary significantly among areas but did vary significantly among trees within each area. Numbers of hollow and Megastigmus -infested (Hymenoptera: Torymidae) seeds varied significantly among areas and trees within areas. Numbers of sound seed increased significantly with increasing cone length but did not change with increasing numbers of cones per cluster. The percentages of Megastigmus -infested seed did not change significantly with increasing cone length or number of cones per cluster.     

Production, losses, and germination of Ceanothus fendleri seeds in an Arizona ponderosa pine forest

I quantified seed production and ovule losses for Ceanothus fendleri Gray (Fendler ceanothus) plants protected from large ungulate herbivores in a ponderosa pine ( Pinus ponderosa [Laws]) forest of northern Arizona. I also tested seed germination responses to cold stratification and heat treatments in the laboratory. Fruit production on fecund stems ranged from 7.4 to 38.2 fruits per stem, which equated to 22.2-118.2 potential seeds based on 3 ovules per fruit. Stems that produced fruit were significantly large relative to their expected sizes. Predispersal ovule losses ranged from 70.7% to 91.4% across the 2 years studied. A chalcidoid seed parasite ( Eurytoma squamosa Bugbee) consumed 11%-28% of the total number of seeds produced. Postdispersal seed predation varied from 0% to 24% and was significantly affected by forest floor substrate in 1 study year. Cumulative ovule losses were estimated to be 71%-92%. Cold stratification did not significantly affect seed germination, and exposure to 90°C resulted in the highest germination percentage. Both dormant and nondormant seeds suggested a bet-hedging life history strategy. This study provides basic ecological information important for management of ponderosa pine forest and nursery production of C. fendleri .     

A seed chalcid ( Eurytoma squamosa Bugbee) parasitizes buckbrush ( Ceanothus fendleri Gray) seeds in a ponderosa pine forest of Arizona

Predispersal seed parasitism rates were quantified for buckbrush ( Ceanothus fendleri Gray) in 3 Arizona ponderosa pine ( Pinus ponderosa Laws.) forest units that had been thinned for ecological restoration objectives. The chalcidoid wasp Eurytoma squamosa Bugbee (Eurytomidae) was responsible for 35% of total seed loss in a single year. These findings represent an expansion of the known range and host list for E. squamosa and increase our understanding of factors that may constrain regeneration of C. fendleri in Southwest ponderosa pine forests.     

Winter food habits of the pine marten in Colorado

Eighteen pine marten ( Martes americana ) stomachs and 29 intestinal tracts, collected between October 1983 and March 1984 from northern Colorado, were examined for food items. Voles ( Microtus spp.) occurred most frequently, followed by shrews ( Sorex spp.), insects, and vegetative matter.     

Plague in pine martens and the fleas associated with its occurrence

Thirteen pine martens ( Martes Americana ) were sampled periodically from July 1979 to September 1980 for plague ( Yersinia pestis ) antibodies and their fleas collected and identified. Four individuals were positive for plague antibodies on 8 of 24 sampling occasions. Titer peaks in these individuals occurred simultaneously in early winter but fell to undetectable levels by late spring. A chipmunk flea ( Monopsyllus ciliatus ) was the most common ectoparasite constituting 55% of all individuals collected. Thirty-one percent of all fleas belonged to Chaetopsylla floridensis, a species previously unreported in California. The remains of ground-dwelling sciurids (chipmunks, Eutamias spp., and ground squirrels, Spermophilus spp.) were very common in marten scats during the period preceding elevated titers. For this reason, and the fact that 92% of all fleas collected from martens during this same period were found more commonly on chipmunks and ground squirrels, these rodents were implicated as the source of the martens’ exposure to plague.     

Status of white pine blister rust in the Intermountain West

During 1995-1997 we conducted a white pine blister rust (WPBR) disease survey in white pines of the Intermountain West. Incidence of WPBR in white pines was 59% overall, 73% in the northern Rocky Mountains, 55% in the middle Rocky Mountains, and 67% in the Sierra Nevada sample stands. Intensity within infected stands averaged 35% and ranged from 2% to 100%. Southward spread of the disease along the western slopes of the Rocky Mountains appears to have slowed or stopped, and the disease was found at the northern and western edges of, but not within, the Great Basin region. Smaller-diameter trees infected with WPBR sustained more severe damage than larger-diameter trees. Mortality and top kill caused by WPBR were very low across the entire study area, but incidence and intensity of the disease appear to have increased substantially in the northern and middle Rocky Mountains since the 1960s.     

Comparative successional roles of trembling aspen and lodgepole pine in the Southern Rocky Mountains

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} A review of the ecological distribution and successional roles of lodgepole pine and trembling aspen in the Southern Rocky Mountains suggests that the two species have different strategies for occupying disturbed sites. Lodgepole pine’s easily dispersed seeds and faster growth from seed in unsuppressed conditions allows it to colonize severe burns, even from remote seed sources. Aspen appears to compensate for ineffective development from seed by vegetative reproduction from durable root stocks, which promotes geographic persistence. Such persistence is achieved by the maintenance of a forest structure conducive to light surface fires, which stimulate suckering and retard conifer invasion, and by the accumulation of soil organic matter, which improves site nutrient retention and water availability.       

On the relative geological ages of amber and copal

Radiocarbon analysis of selected amber and copal specimens yielded infinite radiocarbon ages for amber as expected, but all the copal samples proved to be recent (less than 100 years old), emphasizing the need to base the study of insect inclusions in copal on directly dated material. Some previously studied material assumed to be of Pleistocene age may need to be reassessed.     

Elemental compartmentalization in seeds of Atriplex triangularis and Atriplex confertifolia

Seeds of two halophytes, Atriplex triangularis, which grows in a mesic saline marsh environment, and Atriplex confertifolia, which grows in a xeric desert environment, were analyzed by energy-dispersive X-ray microanalysis for the distribution of elements. The highest concentration of sodium, chlorine, potassium, and calcium was present in seed coats of A. triangularis. All of the elements detected were at low concentrations in the endosperm. Embryos contained the highest amount of phosphorus that is probably associated with organophosphate compounds. Potassium was also high in embryos. The total amount of elements in all regions of A. confertifolia was low as compared to A. triangularis. In a similar pattern sodium, chlorine, potassium, and calcium were the highest in seed coats of A. confertifolia. Elemental concentration was also low in the endosperm. Likewise, the phosphorus level was the highest in the embryo. The results support the concept of elemental compartmentalization in seeds of these halophytes.     

Natural variability of vegetation, soils, and physiography in the bristlecone pine forest of the Rocky Mountains

Pinus aristata Engelm. forest vegetation in Colorado was studied to determine vegetation composition and the relationship between vegetation and environment. Species percent cover, tree size class, and environmental variables were recorded for 49 plots. Previously collected data for 4 plots form New Mexico were included. Environmental variables included latitude, longitude, elevation, slope, aspect, topographic position, parent material, percent rock cover, mean rock size, litter depth, estimated plot age class, and evidence of anthropogenic disturbance. Soils were analyzed for texture, depth, and percent carbon and nitrogen. Pinus aristata foliage was analyzed for percent nitrogen and phosphorus. Direct and indirect gradient analyses (CANOCO) were used to determine environmental factors associated with community composition. Vegetation in P. aristata forests is influenced primarily by elevation and soil pH. Substrate, soil texture, topographic position, and geographic location are secondary factors. Six plant associations were identified using cluster analysis (listed in an elevational sequence from low to high): Pinus aristata/ Festuca arizonica Vasey, Pinus aristata / Festuca thurberi Vasey, Pinus aristata / Juniperus communis L., Pinus aristata / Vaccinium myrtilus L., Pinus aristata / Ribes montigenum McClatchie, and Pinus aristata / Trifolium dasyphyllum Torr. & Gray.     

Response of understory species to changes in ponderosa pine stocking levels in the Black Hills

The objective of this study was to test the hypothesis that there are no differences in understory production, by species, due to stocking levels of Pinus ponderosa (ponderosa pine). Understory production was estimated, by species, on 3 replicates each of 8 growing stock levels, ranging from clearcuts to unthinned stands, in both sapling- and pole-sized pine stands (48 plots) over 3 nonconsecutive years. All stands were approximately 70 yr old when thinning treatments were applied. Production of many herbaceous species, especially Agropyron spp. (wheatgrasses) and Carex spp. (sedges), declined as growing stock levels (measured in terms of basal area) of ponderosa pine increased. While trends in total production were similar, there were specific differences between sapling and pole stands. Sedges and Oryzopsis asperfolia (roughleaf ricegrass) produced more in sapling stands, whereas Danthonia intermedia (timber oatgrass) was more abundant in pole stands. Shrub production, dominated by Acrtostaphylos uva-ursi (bearberry), was relatively consistent across all stocking levels except unthinned. Although the total number of species declined as pine basal area increased, a few species, such as Linnaea borealis (twinflower) and Shepherdia canadensis (buffaloberry), were found only under relatively dense pine canopies. While floristic species richness was greater at lower stocking levels of ponderosa pine, the total number of species would be greater if all stocking levels were present.     

Indicators of red squirrel (Tamiasciurus hudsonicus) abundance in the whitebark pine zone

We investigated occupied squirrel middens and squirrel sightings and vocalizations as indicators of red squirrel ( Tamiasciurus hudsonicus ) abundance in high-elevation whitebark pine ( Pinus albicaulis ) zone. Data were collected 1984-1989 from line transects located on 2 study sites in the Yellowstone ecosystem. We evaluated the performance of each measure on the basis of precision and biological considerations. We concluded that, of the 3 measures, active middens were the best indicator of red squirrel abundance. We also observed that the density of active middens dropped by 48%-66% between 1987 and 1989, following a severe drought and extensive wildfires that burned one of the study sites during 1988.     

Temperature and high salinity effects in germinating dimorphic seeds of Atriplex rosea

Atriplex rosea L. (Chenopodiaceae; tumbling orach), an annual herb, is a widely established weedy species of disturbed sites in all counties of Utah. Seeds of Atriplex rosea were collected from a salt marsh in Faust, Utah, and are dimorphic, light brown, and 2-2.5 mm wide, or black and 1-2 mm wide. Seed germination responses of the black and brown seeds were studied over a range of salinity and temperature. Both brown and black seeds germinated at 1000 mM NaCl, and the optimal temperature for germination of both types was 20°-30°C. Variation in temperature, however, affected germination of black seeds more than brown seeds. At lower thermoperiod only 40%-50% black seeds germinated in nonsaline control, and germination was almost completely inhibited with the inclusion of salinity. However, all brown seeds germinated in control at temperatures above 5°-15°C, and inhibition caused by salinity was comparatively lower. Brown seeds had a higher germination rate than black seeds at all temperature and salinity treatments. The highest rate of germination of both seeds occurred at the temperature regime of 5°-15°C. Recovery of germination for black seeds when transferred to distilled water after being in various salinity treatments for 20 days was quite variable. Recovery decreased with increase in salinity at lower temperature regimes, increased with salinity at optimal thermoperiod, and had no effect at 20°-30°C. Brown seeds recovered poorly from salinity at all thermoperiods except 5°-15°C, where recovery decreased with an increase in salinity. Brown seeds are adapted to germination in the early part of the growing season, whereas black seeds are capable of surviving harsher conditions and can germinate in later time periods. Characteristics of the dimorphic seeds increase chances for survival in the harsh saline desert environment.     

Lagomorphs and the dispersal of seeds into communities dominated by exotic annual weeds

Large areas of western rangeland are presently dominated by alien annual weeds such as Bromus tectorum (cheatgrass). These communities resist succession to perennial communities primarily because the annuals are competitively superior to establishing perennial seedlings and they promote fires that favor weeds over perennials. Succession may be further slowed, however, by low rates of seed dispersal into annual grasslands. We investigated the role of lagomorphs ( Sylvilagus nuttalli , Nuttall's cottontail; S. audubonii , desert cottontail; and Lepus californicus , black-tailed jackrabbit) in seed dispersal across an ecotone: 50 m into woodland, border, and 20 m, 50 m, and 100 m into grassland. We searched pellets for juniper seeds visually and for any other species through germination from crushed pellets after cold, moist stratification. Pellets were not even distributed across transects, but there was no trend with respect to position of transect. Juniperus osteosperma (Utah juniper) was the most abundant seed. Both the number of juniper seeds and the proportion of pellets with juniper seeds decreased steadily from a high in woodland to absence at 100 m into grassland. Only 2 dicot seedlings emerged from pellets, 1 Salsola pestifer and 1 unknown that died prior to identification. Consequently, there was little seed movement into grassland; 72% of all seeds were collected from either woodland or border transects. Lagomorphs apparently do not effectively replenish the native perennial seed pool of cheatgrass-dominated disturbances at Dugway.     

Influence of ponderosa pine overstory on forage quality in the Black Hills, South Dakota

Forage quality was assessed in pole and sapling ponderosa pine ( Pinus ponderosa ) stands growing at five stocking levels—0, 5, 14, 23, and unthinned (which approximated 40 m 2 /ha basal area)—in the Black Hills of South Dakota. Crude protein, acid detergent fiber, acid detergent lignin, ash, calcium, and phosphorus were evaluated for cream peavine ( Lathyrus ochroleucus ), bearberry ( Arctostaphylos uva-ursi ), and timber oatgrass ( Danthonia intermedia ). Acid detergent fiber, acid detergent lignin, and ash showed some significant differences among growing stock levels for cream peavine growing in sapling stands. Crude protein content of timber oatgrass was different among growing stock levels in pole stands. In all cases, however, no trends or patterns relative to stocking levels were evident. When understory forage quality was compared within pole and sapling stands, only 4 of 18 possible comparisons were significant. In general, modifying the overstory of ponderosa pine in the Black Hills by clearcutting or thinning did not result in predictable changes in nutritional values of selected understory species.     

Survival and sprouting responses of Chihuahua pine after the Rodeo-Chediski fire on the Mogollon Rim, Arizona

Chihuahua pines ( Pinus leiophylla Schiede and Deppe var. chihuahuana Engelmann) were surveyed on 11 study plots on the Mogollon Rim in east central Arizona to compare characteristics of trees that sprouted from the base or root collar after the Rodeo-Chediski fire with those of trees that did not sprout. The differences in trees killed and top-killed by the fire versus those that survived were also assessed. Trees that sprouted were significantly smaller in height and diameter at breast height; they also experienced lower fire intensities than trees that did not sprout. Smaller trees had higher incidences of mortality than larger trees. These results indicate that, even though Chihuahua pine has fire resiliency, sprouting rates after fire are related to size of trees, age of trees, and burn intensity. Since Chihuahua pine is a rare species in the area studied, its ability to recover from and tolerate fire could prove advantageous for sustainability.     

Bristlecone pine and Clark's Nutcracker: probable interaction in the White Mountains, California

Many bristlecone pines in the White Mountains, California, are members of multistem clumps. We propose that these clumps have arisen by multiple germinations from seed caches of Clark’s Nutcracker, as occurs in several other pine species. The commonness of nutcrackers and their caching of singleleaf pinyon seeds in the study area provide supporting evidence. Other vertebrates appear unlikely to be responsible for the stem clumps. Seed burial may be required to establish regeneration on these adverse sites where bristlecone pine attains great longevity.        

Insect damage, cone dimensions, and seed production in crown levels of ponderosa pine

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Insect damage to second-year cones was generally not significantly different between crown levels, but was significantly different among areas and among trees within areas for Conophthorus, Megastigmus, and Cydia. Both cone length and width were not significantly different between lower and middle crown, but cone length was significantly greater in the upper crown. Seeds per cone ranged from 34 to 66, but the percent of sound seed per cone varied significantly according to the amount of insect damage.        

An ecological study of bristlecone pine ( Pinus longaeva ) in Utah and eastern Nevada

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} This paper presents data on the distribution of Pinus longaeva on the Markagunt Plateau, Utah; and the Snake, Egan, and White Pine ranges of eastern Nevada. It also presents data on the present-day density and age structure of three P. longaeva populations and the growth rates of individual trees within these populations. Conifer species richness and the relative abundance of P. longaeva varies clinally from the Markagunt Plateau to the White Pine Range. The Markagunt Plateau has relatively high conifer species richness (10 species) and low relative abundance of P. longaeva (1%). The White Pine Range has low conifer richness (4 species) and high P. longaeva relative abundance (34%). Individual tree growth rates were low but highly variable in all populations studied. The three populations studied had mixed age structures with a general trend of more younger individuals at the lower elevations. Possible explanations for the present distribution of P. longaeva and the population structures observed are discussed.     

Species composition and relative abundance of adult fish in Pyramid Lake, Nevada

Pyramid Lake fish populations were sampled with nets on a monthly basis from November 1975 through December 1977. Fish species were taken in the following order of numerical relative abundance: tui chub ( Gila bicolor ), Tahoe sucker ( Catostomus tahoensis ), Lahontan cutthroat trout ( Salmo clarki henshawi ) including cutthroat-rainbow hybrids, cui-ui ( Chasmistes cujus ), and Sacramento perch ( Archoplites interruptus ). Relative abundance estimates are discussed with respect to seasonal availability, spatial distribution of the fish, sampling bias of the fishing methods, and biomass of the fish. Recent temporal trends in the population structure of the lake are presented.