Displacement of Native Riparian Shrubs by Woody Exotics: Effects on Arthropod and Pollinator Community Composition

Throughout the southwestern U.S., riparian gallery forests of cottonwood and willow are being invaded by woody exotics, primarily Russian olive and salt cedar. We wondered what effect this might have on native pollinator populations. Pollinators are indispensable contributors to biodiversity, ecosystem health, and human food production. Recent declines in pollinator abundance and health, such as catastrophic declines in honey bee populations due to Colony Collapse Disorder, has renewed interest in native pollinators and the ecosystem services they provide. Insects were collected from willow, Russian olive and salt cedar throughout April and May of 1997 and 1998 using sweep nets. For each collection day, nets were swept over the target shrubs for a specified number for passes to ensure equal collection effort. Insects were counted and identified to family. Total numbers were adjusted by number of sweep-days. Total insect abundance was greatest for willows (33.5 insects per sweep-day), followed by Russian olive (18.0) and salt cedar (6.8). Willows also had the greatest number of insect orders and families represented. Of the four primary insect pollinator orders, willow had the greatest numbers of dipterans, hymenopterans, and lepidopterans collected per sweep-day. Russian olive had the greatest number of coleopterans. When ants and chalcids were excluded from the hymenopterans, willows still had the greatest numbers and proportions of hymenopterans caught. It appears that the willow habitat is important to pollinating insects, especially bees. In contrast, saltcedar consistently had the lowest numbers and proportions of all four of the pollinator orders

16th Wildland Shrub Symposium Threats to Shrubland Ecosystem Integrity 2010 May 18-20 Logan, UT

Abstract: The 29 papers in this proceedings are divided into the main organized sessions of the 16th Wildland Shrub Symposium, including the plenary session to introduce the theme of threats to shrubland ecosystem integrity, impacts of energy development and reclamation on ecosystem function, invasive plant ecology. wildlife habitats: impacts and restoration opportunities, historical perspectives in shrublands, ecosystem threats due to fire in the Mojave Desert, and modeling and monitoring of shrubland ecosystems. An overarching goal of the symposium was to make linkages between research and management

Preparing and staining mycorrhizal structures in dry bean, sweet corn, and wheat using a block digester

The use of safe staining techniques in the evaluation of mycorrhizal colonization is critical to the continued understanding of this important symbiosis. Several procedures being utilized currently involve regulated and/ or toxic chemicals. The integration of unregulated and nontoxic chemicals into these procedures is important to alleviate potential dangers currently used chemicals pose. We eliminated all regulated reagents by combining portions of several previously published staining and root preservation procedures. A block digester for plant tissue digestion was used as a heating unit and proved to be easier to use, quicker and more reliable than either a water bath or a circulating air oven. Optimum clearing time in KOH varied from 8 to 10 min and 30 to 40 min for wheat, sweet corn, and dry bean roots, respectively. We also successfully used both drying and freezing of roots for storage prior to staining. These modified procedures were quick and easy and provided reliable temperature control and excellent staining while protecting individuals and the environment from toxic chemicals

Response of Two Semiarid Grasslands to a Second Fire Application

Prescribed fire was used in two semiarid grasslands to reduce shrub cover, promote grass production, and reduce erosional loss that represents a potential non-point-source of sediment to degrade water quality. This study measured transported soil sediment, dynamics in soil surface microtopography, cover of the woody shrub, grass, and bare ground cover classes, and soil fertility measured by nitrogen-mineralization potentials for the respective cover classes over a 9-year period during which 2 fires occurred. In general, the effects of two drought periods were equal to or greater than the effects of fire on the measured parameters. Following the second fire at the grama grass-dominated site, the number of live junipers was significantly lowered (P < 0.001). Fire consumed grass and shrub cover, which created the potential for greater transport of sediment and loss in soil surface elevation. Soil fertility under shrubs was significantly higher than soil fertility under grasses in both grassland sites before and after the first fire; however, that highly significant pattern was not present after the second fire for about 2 years at both sites. This suggests that the reestablishment of a natural fire frequency would likely dampen the well-documented pattern of greater soil fertility under shrub islands relative to grass islands. Repeat use of prescribed fire may keep shrub cover in check and promote fundamental changes in soil processes within semiarid grasslands, but its value must be weighed against the increased potential for erosion following fire. The Rangeland Ecology & 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 2020Legacy DOIs that must be preserved: 10.2458/azu_jrm_v59i1_carleto

CYANOBACTERIA AND CYANOLICHENS: CAN THEY ENHANCE AVAILABILITY OF ESSENTIAL MINERALS FOR HIGHER PLANTS?

Volume: 53Start Page: 59End Page: 7

Foreword: Humans in Changing Shrubland Ecosystems

The Rangelands 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 March 202

WINTER NUTRIENT CONTENT AND DEER USE OF GAMBEL OAK TWIGS IN NORTH CENTRAL UTAH

Volume: 52Start Page: 293End Page: 29