The Effect of Varying Environmental Conditions on Phytolith Morphometries in Two Species of Grass (Bouteloua curtipendula and Panicum virgatum)

Solid deposits of SiO2 (phytoliths) accumulate in many plants in specific intracellular and extracellular locations. Phytoliths have morphological characteristics unique to some taxa and therefore have taxonomic significance. Phytoliths persist and maintain their morphological integrity long after a plant has died, thus becoming a microfossil of the plant that produced them. Development of phytolith sytematics for microfossil phytoliths has traditionally followed a typological approach based on simple verbal descriptions of shape. A new method for use in phytolith sytematics is the morphometric approach which employs computer-based Image Analysis Systems to make quantified measurements of morphological parameters (size, shape, texture, etc.) which can be used as discriminators between taxa. These parameters, called morphometrics, or morphometries, are potentially important for improved phytolith sytematics. This study evaluates the effect of varying environmental conditions on 18 different phytolith morphometries relative to shape and size as a prerequisite to the further development of a morphometric based phytolith taxonomy. Results indicate that environmental conditions do indeed effect phytolith morphometries for the silica cell phytoliths produced by the two grass species considered in this study. However, the effects are not usually significant (p ≤ 0.05). Moreover, results of discriminant analyses using the morphometric data obtained indicate that the varying environmental conditions did not hinder the potential of phytolith morphometries to discriminate between plant taxa

Ecological Adaptations Of Salt Marsh Grass, Distichlis Spicata (Gramineae), And Environmental Factors Affecting Its Growth And Distribution

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142123/1/ajb211851.pd

Vulnerability to xylem cavitation and the distribution of sonoran desert vegetation

Journal ArticleWe studied 15 riparian and upland Sonoran desert species to evaluate how the limitation of xylem pressure (Vx) by cavitation corresponded with plant distribution along a moisture gradient. Riparian species were obligate riparian trees (Fraxinus velutina, Populus fremontii, and Salix gooddingii), native shrubs (Baccharis spp.), and an exotic shrub (Tamarix ramosissima). Upland species were evergreen (Juniperus monosperma, Larrea tridentata), drought-deciduous (Ambrosia dumosa, Encelia farinosa, Fouquieria splendens, Cercidium microphyllum), and winter-deciduous (Acacia spp., Prosopis velutina) trees and shrubs

Early intervention in Portugal: study of professionals’ perceptions

Early intervention (EI) has been characterized by considerable advances in its domain, which has had great repercussions in the implementation of the family-centered approach. These changes have had implications in the practices and in the adoption and learning of new values that should be implemented in EI. This study evaluates the professional perspectives regarding familycentered practices in EI programs in Portugal. The results highlight the importance of effective collaboration and coordination between health, education, and social services and the importance of providing child and family support in a natural context. These results reinforce the need to invest in professional training to improve the quality of services offered to families in EI.Fundação para a Ciência e a Tecnologia (FCT) no âmbito do projecto PEst-OE/CED/UI1661/2014 do CIEd

ECOLOGICAL AND COMMUNITY RELATIONSHIPS OF ERIOGONUM-CORYMBOSUM POLYGONACEAE IN THE UINTA BASIN UTAH USA

Volume: 39Start Page: 177End Page: 19

Microhabitat Relationships of Six Major Shrubs in Navajo National Monument, Arizona

Six shrub species were studied to determine their microhabitat relationships as well as their effect on the immediate environment. Analysis of site characteristics and mineral composition of soils in open areas adjacent to shrubs and beneath shrubs allowed for comparison of the different habitats following shrub establishment. Soil pH differs beneath the various shrubs and all six species tended to create more alkaline soils beneath their canopy. All species showed increased soil salinity beneath their canopy. However, the concentration of total soluble salts in the soil surface beneath the shrubs varied with the species and was highest beneath fourwing saltbush. Significant increases in the concentration of magnesium and potassium ions beneath shrubs were observed. Nitrogen and phosphorus were also found in greater concentration beneath the shrub canopy. Soil depth differed beneath the shrub species, with sagebrush and fourwing saltbush growing on the deeper more highly developed types. There was a positive relationship between the presence of shrubs and the depth of the soil profile.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Differentiation of Serviceberry Habitats in the Wasatch Mountains of Utah

Utah serviceberry (Amelanchier utahensis Koehne) and its habitats were studied in the Wasatch Mountains of central Utah. Twenty-five populations were selected and sampled for various biotic and abiotic environmental variables. Regression, correlation, cluster, and discriminant analyses were used to analyze the data. Sites of northern exposure exhibited a more luxuriant vegetation than southern exposures. Although all the study sites contained Utah serviceberry as a dominant or subdominant plant, they can be classified into three major habitat types according to associated dominants and/or geographical location. These groups are serviceberry-dominated foothill knolls; oak-serviceberry-dominated northern exposures; and serviceberry-dominated southerly exposures. Analyses demonstrated overlap between the major selected habitat types. The most distinct habitat was the foothill knolls; the least distinct was the southern exposed serviceberry habitat. The serviceberry habitat on southerly exposures is environmentally intermediate between the foothill knolls and higher elevation northern exposed sites on which serviceberry shares dominance with oak. Discriminant analysis indicated that pH, slope, sand, soluble salts, and clay were the environmental factors most important in distinguishing between the major habitat types.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Habitat Relationships of Basin Wildrye in the High Mountain Valleys of Central Utah

Habitat relationships between stands of basin wildrye (Elymus cinereus) and adjacent sagebrush-grass steppe were studied in the Strawberry Valley of central Utah. Fifteen sites of basin wildrye and 15 adjacent sites of sagebrush-grass steppe were selected and sampled for various biotic and abiotic environmental variables. Stands of basin wildrye were dominated by this grass (90% composition). The adjacent sagebrush-grass steppe exhibited more diversity of species and life forms. Basin wildrye and badger diggings were correlated 95% of the time. Potassium concentrations (P<.05) and soil depth (P<.01) were significantly greater in the basin wildrye sites. Secondary successional patterns were observed on disturbed sites.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Seasonal Variation of Monoterpenoids in Big Sagebrush (Artemisia tridentata)

Monthly monoterpenoid content was determined for 16 big sagebrush (Artemisia tridentata) plants grown on a uniform garden. These 16 plants were selected at random from 4 accessions of basin big sagebrush (A.t. ssp. tridentata)-4 plants per accession. A composite sample was taken for a fifth accession of mountain big sagebrush (A.t. vaseyana). Monoterpenoid content varied seasonally with the lowest content occurring during May (0.97% of dry matter). Highest monoterpenoid content occurred during July (4.18%) followed by August (3.36%) and September (2.73%). Dove Creek (2.61% of dry matter) and Marysvale (2.64%) basin big sagebrush accessions contained significantly higher pooled levels of monoterpenoids than the Indianola (1.73%) and Loa (1.55%) big sagebrush accessions. The composite samples of the Indian Peaks mountain big sagebrush accession, an accession significantly preferred over the Marysvale and Loa accessions, contained an overall monoterpenoid level of 2.82%. Adverse relationships between monoterpenoid content and the consumption of big sagebrush by wintering mule deer seem weak.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202