Search Results

Post-fire recovery of arid shrublands is typically slow, and planting greenhouse-raised seedlings may be a means of jump-starting this process. Recovery can be further accelerated by understanding the factors controlling post-planting survival. In fall 2007 and 2009, we outplanted seedlings of two contrasting native evergreen shrubs—fast-growing Nevada jointfir and slow-growing...

Relatively little attention has been paid to the economic potentials and limitations of tropical timber production and management at smallholder scales, with the most relevant research focusing on community forestry efforts. As a rare tropical example of long-lasting small-scale timber production, in this study we explore the economics of smallholder...

Non-native fishes have been known from freshwater ecosystems of Florida since the 1950s, and dozens of species have established self-sustaining populations. Nonetheless, no synthesis of data collected on those species in Florida has been published until now. We searched the literature for peer-reviewed publications reporting original data for 42 species...

The impacts of introduced northern pike (Esox lucius) on salmonid populations have attracted much attention because salmonids are popular subsistence, sport and commercial fish. Concern over the predatory effects of introduced pike on salmonids is especially high in Southcentral Alaska, where pike were illegally introduced to the Susitna River basin...

The latest Cretaceous to early Palaeogene Orocopia Schist and related units are generally considered a low-angle subduction complex that underlies much of southern California and Arizona. A recently discovered exposure of Orocopia Schist at Cemetery Ridge west of Phoenix, Arizona, lies exceptionally far inland from the continental margin. Unexpectedly, this...

The Virgin Islands and Whiting basins in the Northeast Caribbean are deep, structurally controlled depocentres partially bound by shallow-water carbonate platforms. Closed basins such as these are thought to document earthquake and hurricane events through the accumulation of event layers such as debris flow and turbidity current deposits and the...

The biological control agent (tamarisk leaf beetle, Diorhabda spp.) is actively being used to defoliate exotic saltcedar or tamarisk (Tamarix spp.) in riparian ecosystems in western USA. The Virgin River in Arizona and Nevada is a system where tamarisk leaf beetle populations are spreading. Saltcedar biocontrol, like other control methods,...

This study explores the removal rate of nitrobenzene (NB) using a new gas-liquid-liquid (G-L-L) three-phase ozone loaded system consisting of a gaseous ozone, an aqueous solvent phase, and a fluorinated solvent phase (perfluorodecalin, or FDC). The removal rate of NB was quantified in relation to six factors including 1) initial...

Introduced exotic plants can drive ecosystem change. We studied invasion and establishment ofBrassica tournefortii (African mustard), a noxious weed, in the Chemehuevi Valley, western Sonoran Desert, California. We used long-term data sets of photographs, transects for biomass of annual plants, and densities of African mustard collected at irregular intervals between 1979...

The foraging ecology and diet of the green turtle, Chelonia mydas, remain understudied, particularly in peripheral areas of its distribution. We assessed the diet of an aggregation of juvenile green turtles at the northern edge of its range during winter months using two approaches. Stomach content analyses provide a...

Conversion of native prairie to agriculture has increased food and bioenergy production but decreased wildlife habitat. However, enrollment of highly erodible cropland in conservation programs has compensated for some grassland loss. In the future, climate change and production of second-generation perennial biofuel crops could further transform agricultural landscapes and increase...

Management goals to improve the recovery of steelhead (Oncorhynchus mykiss) stocks at risk of extinction include increasing the proportion of postspawning fish that survive and spawn again. To be successful, postspawning steelhead (kelts) migrating downstream to the ocean must prepare physiologically and physically for a seawater transition. We sampled blood,...

Few systematic studies of valley-scale geomorphic drivers of streamflow regimes in complex alpine headwaters have compared response between catchments. As a result, little guidance is available for regional-scale hydrological research and monitoring efforts that include assessments of ecosystem function. Physical parameters such as slope, elevation range, drainage area and bedrock...

Spawning behavior of lake trout, Salvelinus namaycush, is poorly understood, relative to stream-dwelling salmonines. Underwater video records of spawning in a recovering population from the Drummond Island Refuge (Lake Huron) represent the first reported direct observations of lake trout spawning in the Laurentian Great Lakes. These observations provide...

Diatom and silicoflagellate assemblages documented in a high-resolution time series spanning 800 to 1600 AD in varved sediment recovered in Kasten core SPR0901-02KC (34°16.845’ N, 120°02.332’ W, water depth 588 m) from the Santa Barbara Basin (SBB) reveal that SBB surface water conditions during the Medieval Climate Anomaly (MCA) and...

Exotic species present a great threat to native fish conservation; however, eradicating exotics is expensive and often impractical. Mechanical removal can be ineffective for eradication, but nonetheless may increase management effectiveness by identifying portions of a watershed that are strong sources of exotics. We used mechanical removal to understand processes...

Land-use change around protected areas limits their ability to conserve biodiversity by altering ecological processes such as natural hydrologic and disturbance regimes, facilitating species invasions, and interfering with dispersal of organisms. This paper informs USA National Wildlife Refuge System conservation planning by predicting future land-use change on lands within 25...

Sediment rating curves, which are fitted relationships between river discharge (Q) and suspended-sediment concentration (C), are commonly used to assess patterns and trends in river water quality. In many of these studies it is assumed that rating curves have a power-law form (i.e., C = aQb, where a and b...

We present an inversion strategy capable of using real-time high-rate GPS data to simultaneously solve for a distributed slip model and fault geometry in real time as a rupture unfolds. We employ Bayesian inference to find the optimal fault geometry and the distribution of possible slip models for that geometry...

Use of electronic transmitter and monitoring systems to track movements of aquatic animals has increased continuously since the inception of these systems in the mid-1950s. The purpose of the present report is to provide information about veterinary principles and their incorporation into surgical implantation procedures for fish. We also intend...

Conservationists are in need of objective metrics for prioritizing the management of habitats. For individual species, the threat of extinction is often used to prioritize what species are in need of conservation action. Using long-term monitoring data, we applied a Bayesian diffusion approximation to estimate quasi-extinction risk for 54 native...

It has been argued that regional collaboration can facilitate adaptation to climate change impacts through integrated planning and management. In an attempt to understand the underlying institutional factors that either support or contest this assumption, this paper explores the institutional factors influencing adaptation to climate change at the regional scale,...

Simulating groundwater flow in a water-table (unconfined) aquifer can be difficult because the saturated thickness available for flow depends on model-calculated hydraulic heads. It is often possible to realize substantial time savings and still obtain accurate head and flow solutions by specifying an approximate saturated thickness a priori, thus linearizing...

Genetic diversity is assumed to reflect the evolutionary potential and adaptability of populations, and thus quantifying the genetic diversity of endangered species is useful for recovery programs. In particular, if conservation strategies include reintroductions, periodic genetic assessments are useful to evaluate whether management efforts have resulted in the maximization or...

Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments of captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine whether selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were...