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......against hurricanes, abundant wildlife, provision of drinking...against hurricanes, abundant wildlife, provision of drinking...traditional and renewable energy sources; promotion of...comprehensive national energy policy. The vision of......
Recovery rates of cyanobacterial-lichen soil crusts from disturbance were examined. Plots were either undisturbed or scalped, and scalped plots were either inoculated with surrounding biological crust material or left to recover naturally. Natural recovery rates were found to be very slow. Inoculation significantly hastened recovery for the cyanobacterial/green algal component, lichen cover, lichen species richness, and moss cover. Even with inoculation, however, lichen and moss recovery was minimal. Traditional techniques of assessing recovery visually were found to underestimate time for total recovery. Other techniques, such as extraction of chlorophyll a from surface soil and measurement of sheath material accumulation,...
We revisit the serial discontinuity concept (SDC), which predicts river ecosystem responses to stream regulation in the context of recovery with distance downstream from the dam (discontinuity distance). Many studies have described pervasive interruptions of natural biophysical gradients of dams by comparing conditions in tailwaters to reference or pre-impoundment conditions. But only a few studies provide data or interpretations that explicitly test the SDC within entire stream corridors or along specifically defined reaches where recovery was expected in view of the predictions of the SDC. We present discontinuity distance measures for nine rivers around the world where the predictions of the SDC were substantiated....
Increasingly, environmental quality is becoming recognized as a critical factor that should constrain land use planning. One important measure of a landscape's quality is its capacity to support viable populations of wildlife species. But the ability of land managers to balance conservation with other competing objectives is limited by a shortage of methodologies for assessing landscape quality. In response to this shortage, the research community has begun developing a variety of multispecies, landscape-level, assessment models. Useful models must strike a balance between parsimony and biological realism and must be designed to make the most of limited life history data. This paper applies two such assessments...
The pine forests in the southern portion of the Rocky Mountains are a heterogeneous mosaic of disturbance and recovery. The most extensive and intensive stress and mortality are received from human activity, fire, and mountain pine beetles (MPB;Dendroctonus ponderosae). Understanding disturbance interactions and disturbance-succession pathways are crucial for adapting management strategies to mitigate their impacts and anticipate future ecosystem change. Driven by this goal, we assessed the forest disturbance and recovery history in the Southern Rocky Mountains Ecoregion using a 13-year time series of Landsat image stacks. An automated classification workflow that integrates temporal segmentation techniques and...
Chemical composition of 24 elements for sed- iments and suspended solids, water parameters and the diatoms from Yatsushiro Bay tidal flat, Kuma River, and Arase Dam have been determined to examine changes from 2002 to 2013. In 2002, sediment delivered to the bay by the Kuma River was restricted by the Arase Dam; however, in April 2010 two gates were opened and also repeated sea- sonal flushing allowing resumption of natural sediment transport. Bulk chemical composition of the tidal flat sed- iments has changed since 2002, with marked decreases in concentrations of As, Zn, Pb and total sulfur. Decreased heavy metal contents in 2012 and 2013 for bay sediments after opening the dam and repeated flushing is attributed...
BACKGROUND AND AIMS: The basic parameters of water relations were measured in Sphagnum mosses. The relationships of these parameters to the photosynthetic response to desiccation and the ecology of these mosses were then tested. METHODS: The water relations parameters of six Sphagnum species (mosses typical of wet habitats) and Atrichum androgynum (a moss more typical of mesophytic conditions) were calculated from pressure-volume isotherms. Photosynthetic properties during and after moderate desiccation were monitored by chlorophyll fluorescence. KEY RESULTS: When desiccated, the hummock-forming species S. fuscum and S. magellanicum lost more water before turgor started dropping than other sphagna inhabiting less...
In this paper, we synthesize a series of small dam removal studies to examine how changes in channel form can affect riparian vegetation, fish, macroinvertebrates, mussels, and nutrient dynamics. Each of the ecosystem attributes responded to the disturbance of dam removal in different ways and recovered at very different rates, ranging from months to decades. Riparian vegetation appeared to require the greatest time for recovery, while macroinvertebrates had the least. Mussel communities were the most adversely affected group of species and showed no signs of recovery during the time period of the study. Based on these and other studies, we suggest that ecosystems may follow two trajectories of recovery following...
Recovery of soil properties from World War II-era military training exercises in the Mojave Desert was measured approximately 55 years following disturbance. Tracks from military vehicles were still visible, particularly in areas of desert pavement. Soil penetrability was much lower in visible tracks than outside the tracks. Soils in tracks had fewer rocks in the top 10cm of the soil profile than adjacent untracked soils. Larger particles (> 4.8mm) formed a moderately well-developed pavement outside of the tracks, while smaller, loose particles ( h 4.8mm) dominated the surface of the tracks. The time required to restore the desert pavement is likely to be measured in centuries. Based on biomass estimates, the cyanobacterial...
Species conservation via the Endangered Species Act is highly politicized, yet few data have been gathered to illustrate the relationship of political party affiliation to species conservation perspectives. We conducted a nationwide public opinion survey and found that Democrats value species conservation more highly than do Republicans, and that Democrats are also more strongly supportive of the Endangered Species Act. Republicans place higher value on property rights than do Democrats, but members of both parties value economic growth as highly as wildlife conservation. The results imply that the Democratic propensity to value species conservation reflects a biocentric perspective that does not bode well for practical...
Sarcobatus vermiculatus (Hook) Torrey is a leaf succulent, sodium-accumulating shrub usually found in saline substrates of the Great Basin desert, Utah, USA. Laboratory experiments were conducted to determine the effect of salinity (0, 200, 400, 600, 800 and 1000 mM NaCl) and temperature (day/night: 5/15, 10/20, 15/25, 20/30, and 25/35�C) on seed germination. S. vermiculatus showed 100% germination in non-saline controls, at all thermoperiods. Percentage and rate of germination decreased with increases in salinity and few seeds germinated at even 1000 mM NaCl. High salinity exposure caused the loss of viability at higher temperature regimes, while some recovery was recorded in low salinity treatments. Published...