Filters: Tags: Populus (X)
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A new species of poplar is recognized based on abundant specimens from the early Middle Eocene Parachute Creek Member of the Green River Formation in eastern Utah and western Colorado and compared with two other contemporary species. A rare twig bearing both leaves and fruits serves as a Rosetta stone, linking the vegetative and reproductive structures that formerly were only known from dispersed organs. Fruit and foliage characters distinguish Populus tidwellii sp. n. from Populus cinnamomoides (Lesquereux) MacGinitie (typified on specimens from Green River Station, WY), to which the isolated leaves had formerly been attributed. In addition, new data from fruits and foliage confirm that there were two distinct...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado,
International Journal of Plant Sciences,
Montana,
Populus,
Pseudosalix,
In many places along the lower Colorado River, saltcedar (Tamarix spp) has replaced the native shrubs and trees, including arrowweed, mesquite, cottonwood and willows. Some have advocated that by removing saltcedar, we could save water and create environments more favourable to these native species. To test these assumptions we compared sap flux measurements of water used by native species in contrast to saltcedar, and compared soil salinity, ground water depth and soil moisture across a gradient of 200?1500 m from the river's edge on a floodplain terrace at Cibola National Wildlife Refuge (CNWR). We found that the fraction of land covered (fc) with vegetation in 2005?2007 was similar to that occupied by native...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: EVI,
Ecohydrology,
MODIS,
Pluchea,
Populus,
Human activities have caused the decline of numerous species and ecosystems. To promote ecosystem resilience, recent management efforts aim to maintain ecosystem patterns and processes within their historical range of variability. There has been substantial concern that quaking aspen, the most widely distributed tree in North America and the most important deciduous tree in the subalpine forests of the Rocky Mountains, has declined significantly in the western landscape during the 20th century. This reported decline has been attributed to conifer encroachment associated with fire exclusion, as well as other causes. To assess long-term changes in the extent of quaking aspen in a 175000-ha study area in western Colorado,...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado,
Ecological Applications,
USA,
aspen,
fire,
Groundwater is a key driver of riparian condition on dryland rivers but is in high demand for municipal, industrial, and agricultural uses. Approaches are needed to guide decisions that balance human water needs while conserving riparian ecosystems. We developed a space-for-time substitution model that links groundwater change scenarios implemented within a Decision Support System (DSS) with proportions of floodplain vegetation types and abundances of breeding and migratory birds along the upper San Pedro River, AZ, USA. We investigated nine scenarios ranging from groundwater depletion to recharge. In groundwater decline scenarios, relative proportions of tall-canopied obligate phreatophytes (Populus/Salix, cottonwood/willow)...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Ecohydrology,
Populus,
Tamarix,
avian abundance,
dryland river,
Categories: Publication;
Types: Citation;
Tags: Arid Lands,
D 04125 Temperate forests; SW 0860 Water and plants,
Detritus,
Ecology Abstracts; Water Resources Abstracts,
Exotic Species,
Categories: Publication;
Types: Citation;
Tags: Abundance,
Canada, Alberta,
Clear cutting,
D 04672 Mammals,
Ecology Abstracts,
Categories: Publication;
Types: Citation;
Tags: Arid Zone,
Arid environments,
Cottonwood Trees,
Fremont cottonwood,
Growth,
Categories: Publication;
Types: Citation;
Tags: ASFA 3: Aquatic Pollution & Environmental Quality; Ecology A,
Air pollution,
Eastern cottonwood,
Growth rate,
Man-induced effects,
Effectiveness of environmental flows for riparian restoration in arid regions: A tale of four rivers
Environmental flows have become important restoration tools on regulated rivers. However, environmental flows are often constrained by other demands within the river system and thus typically are comprised of smaller water volumes than the natural flows they are meant to replace, which can limit their functional efficacy. We review environmental flow programs aimed at restoring riparian vegetation on four arid zone rivers: the Tarim River in China; the Bill Williams River in Arizona, U.S.; the delta of the Colorado River in Mexico; and the Murrumbidgee River in southern Australia. Our goal is to determine what worked and what did not work to accomplish restoration goals. The lower Tarim River in China formerly formed...
Categories: Publication;
Types: Citation;
Tags: Acari,
Canada, Alberta,
Coleoptera,
Diptera,
Entomology Abstracts; Ecology Abstracts,
Categories: Publication;
Types: Citation;
Tags: Anacampsis niveopulvella,
Biological diversity,
Community composition,
Entomology Abstracts; Ecology Abstracts,
Gelechiid moths,
Tamarix spp. removal has been proposed to salvage water and allow native vegetation to recolonize western U.S. riparian corridors. We conducted wide-area studies on the Lower Colorado River to answer some of the scientific questions about Tamarix water use and the consequences of removal, combining ground surveys with remote sensing methods. Tamarix stands had moderate rates of evapotranspiration (ET), based on remote sensing estimates, averaging 1.1 m/yr, similar to rates determined for other locations on the river and other rivers. Leaf area index values were also moderate, and stands were relatively open, with areas of bare soil interspersed within stands. At three Tamarix sites in the Cibola National Wildlife...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Populus,
Prosopis,
Restoration Ecology,
Salix,
Tamarix,
As global climate change affects recharge and runoff processes, stream flow regimes are being altered. In the American Southwest, increasing aridity is predicted to cause declines in stream base flows and water tables. Another potential outcome of climate change is increased flood intensity. Changes in these stream flow conditions may independently affect vegetation or may have synergistic effects. Our goal was to extrapolate vegetation response to climate-linked stream flow changes, by taking advantage of the spatial variation in flow conditions over a 200 km length of the San Pedro River (Arizona). Riparian vegetation traits were contrasted between sites differing in low-flow hydrology (degree of stream intermittency)...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Populus,
River Research and Applications,
Tamarix,
climate change,
flood disturbance,
Categories: Publication;
Types: Citation;
Tags: D 04640 Other angiosperms,
Ecology Abstracts,
Populus,
Salix exigua,
USA, Utah,
Categories: Publication;
Types: Citation;
Tags: ASFA 1: Biological Sciences & Living Resources; ASFA 3: Aqua,
Arid environments,
Available Water,
Biological stress,
Competition,
Categories: Publication;
Types: Citation;
Tags: Antimony,
Argentina,
Argentina,
Atomic Absorption Spectrophotometry,
Bioaccumulation,
Cottonwoods (Populus spp.) are adapted to ripar-ian or floodplain zones throughout the Northern Hemisphere; they are also used as parents for fast-growing hybrid poplars. We review recent ecophysiological studies of the native cottonwoods Populus angustifolia James, P. balsamifera L., P. deltoides Marsh., P. fremontii S. Watson and P. trichocarpa T. & G. in North America, and P. nigra L. in Europe. Variation exists within and across species and hybrids; however, all riparian cottonwoods are dependent on shallow alluvial groundwater that is linked to stream water, particularly in semi-arid regions. This conclusion is based on studies of their natural occurrence, decline following river damming and dewatering (water...
Categories: Publication;
Types: Citation;
Tags: D 04140 Taiga/tundra; D 04640 Other angiosperms,
Ecology Abstracts,
Pinus strobus,
Populus,
USA, Michigan,
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