bluuebunny/crossref_metadata_2025 huggingface dataset:
A remarkable sand-dwelling fish assemblage from central Amazonia, with comments on the evolution of psammophily in South American freshwater fishes
Authors: Zuanon Jansen , Bockmann Flávio A. , Sazima Ivan
Published: December 2007

We studied a specialised assemblage of sand-dwelling fish species from a streamlet in central Amazonia. The five sanddwelling species comprised 15.2 % of the total number in the streamlet (33 species). Two of the sand-dwellers are daytime foragers, Characidium cf. pteroides (Crenuchidae) and Stauroglanis gouldingi (Trichomycteridae), whereas three ones are night-time foragers, Gymnorhamphichthys rondoni (Rhamphichthyidae), "Imparfinis" pristos and Mastiglanis asopos (Heptapteridae). With the exception of C. cf. pteroides, the remainder species bury in the sand during their resting period. All five species bear a cryptic, sand-colour pattern, and some are translucent, traits which we regard as advantageous both for evasion from predators and for approaching prey (for the daytime foragers). All five species are microphagous carnivores and their foraging tactics range from generalised sit-and-wait (C. cf. pteroides) to active searching for interstitial prey (G. rondoni). A unique "drift-trap" system made up by the extended barbels and filamentous first pectoral-fin rays is employed by M. asopos. We regard the small size and low number of vertebrae (which is functionally expressed by fast displacements in the sand) as additional features advantageous to explore the sand habitat, allowing diving quickly in the substrate to evade predators and to forage for small prey in sand interstices or plant debris. The relationship between morphological and behavioural characters suited to life in sandy substrates is examined under the perspective of the current phylogenies for each group of psammophilous fishes here studied. The mapping of these characters demonstrates that not all of them evolved specifically for strict psammophily. Instead, some of them may represent the final step of a transformation series or synapomorphies of higher hierarchical levels. Several characters linked to psammophily, such as small body, large eyes, and scarce pigmentation are probably paedomorphic traits. We consider that the little variable specific composition of fish sand-dwelling assemblages and the wide (although patchy) geographical distribution of their species in the Amazon are due to the widespread occurrence and low complexity of this specialised habitat. The pre-existence of benthic habits, small size, and the broad distribution of rivers with sandy beds, mainly in the Amazon and Orinoco basins, possibly played a determinant role in the origin and diversification of psammophilous assemblages among freshwater fishes in South America.
Fallen leaves on the water-bed: diurnal camouflage of three night active fish species in an Amazonian streamlet
Authors: Sazima Ivan , Carvalho Lucélia Nobre , Mendonça Fernando Pereira , Zuanon Jansen
Published: December 2007

Resemblance to dead leaves is a well known type of camouflage recorded for several small vertebrates that dwell in the leaf and root litter on the ground. We present here instances of such resemblance in three species of nocturnal fishes (Siluriformes and Gymnotiformes) that spend the daytime among submersed root-tangle with leaf litter in Amazonian streams. All three species are very difficult to spot visually, due both to their shape and colors which blend with the substrate, as well as to the heterogeneous nature of their cover. Two species were recorded to lie on their sides, which adds to their resemblance to dead leaves. When disturbed, one species may drift like a waterlogged leaf, whereas another moves upwards the root-tangle, exposing its fore body above the water surface. We regard their leaf-like shapes, cryptic colors, and escape movements as a convergence in defensive responses to visually hunting aquatic vertebrates, most likely diurnal predaceous fishes.
A review of the species of Crenicichla (Teleostei: Cichlidae) from the Atlantic coastal rivers of southeastern Brazil from Bahia to Rio Grande do Sul States, with descriptions of three new species
Authors: Kullander Sven O. , Lucena Carlos A. Santos de
Published: December 2007

Six species of Crenicichla, three of which are new, are recognized from the Atlantic coastal rivers of souhteastern Brazil from the state of Bahia south to the state of Rio Grande do Sul: C. mucuryna (upper rio Mucuri, Minas Gerais), C. lacustris (from the rio Paraíba do Sul north to the rio Buranhem, Bahia), C. iguapina, new species (rio Ribeira de Iguape), C. tingui, new species (from the rio Itapocu to the rio Nhundiaquara drainage), C. maculata, new species (lagoa dos Quadros, rio Maquiné, Rio Grande do Sul to rio Itapocu, Santa Catarina drainages), and Crenicichla punctata (laguna dos Patos basin). Crenicichla biocellata is a synonym of C. lacustris; and also a secondary homonym of Sparus biocellatus, a synonym of C. saxatilis. Crenicichla dorsocellata is also a synonym of C. lacustris.
Redescription of the type species of Odontostilbe Cope, 1870 (Teleostei: Characidae: Cheirodontinae), and description of three new species from the Amazon basin
Authors: Bührnheim Cristina M. , Malabarba Luiz R.
Published: December 2007

The widespread Neotropical cheirodontine Odontostilbe fugitiva is reviewed, and three new species of the genus are described from the Amazon basin. A neotype is designated for O. fugitiva, from the mouth of the río Mazán, upper río Amazonas basin, Peru. Three nominal species are herein considered as synonyms of O. fugitiva: O. madeirae, O. drepanon, and O. caquetae. The three new species are respectively O. ecuadorensis from the río Napo basin, O. nareuda from the rio Madeira basin, and O. parecis from the rio Guaporé basin (rio Madeira basin). Among other diagnostic characters, gill rakers are especially informative in distinguishing species. Description of gill raker denticulation is provided for the first time for species of the Cheirodontinae. Secondary sexually dimorphic characters are described for all species.
The almost invisible league: crypsis and association between minute fishes and shrimps as a possible defence against visually hunting predators
Authors: Carvalho Lucélia Nobre , Zuanon Jansen , Sazima Ivan
Published: December 2007

Camouflage is one of the most widespread defence modes used by substrate-dwelling animals, whereas transparency is generally found in open-water organisms. Both these defence types are regarded as effective against visually guided predators. We present here three assemblages of similarly-sized freshwater fish and shrimp species which apparently rely on camouflage and transparency to evade some of their potential predators. In one of the associations, there is a transition from cryptic colours and translucency to transparency of the component species according to the position each of them occupies in the habitat. The likeness between the fishes and the shrimps is here regarded as a type of protective association similar to numerical or social mimicry. Additionally, we suggest that the assemblage may contain Batesian-like mimicry components.
Effects of the proximity from an industrial plant on fish assemblages in the rio Paraíba do Sul, southeastern Brazil
Authors: Pinto Benjamin Carvalho Teixeira , Peixoto Magna Galvão , Araújo Francisco Gerson
Published: December 2007

This work aims to analyze changes in the fish assemblages along a longitudinal reaches of the rio Paraíba do Sul, one of the most used Brazilian aquatic systems, to assess the river "health" and to identify eventual recovery trends. Standardized monthly samplings were carried out at six sites, from October 1997 to September 1999, using casting, sieves, seine and gill nets. Three zones were searched: upstream (Z I), downstream (Z III) and nearby the source of pollution (Z II). Three univariate distribution methods were used: ABC (abundance-biomass curves), K-dominance curves, and geometric class's distribution. Additionally, cluster analysis was applied to detect eventual patterns. The ABC and K-dominance curves showed Z II with evident indication of stress in both yearly cycles, followed by Z III and Z I. Few rare species and absence of common species in Z I, presence of common and abundant species, mainly opportunist, in Z II, and the highest number of rare species in Z III, was the overall pattern showed by geometric class. Number of fish was higher at Z II, while number of species did no change significantly among zones. Cluster analysis separate Z II samples from Z I and III. All the three univariate methods showed evident signals of stress at Z II, which showed indication of organic enrichment as expressed in the high abundance of common species, although physicochemical variables (ammonia, nitrogen, total phosphorous and DBO) have increased slightly from Z1 to Z III. A lesser stress condition was shown at the downstream zone (Z III), indicating the river recovery capacity. The use of biological indicators in this study proved to be a better tool to assess non-point sources pollution when compared to traditional physicochemical measurements.
Preliminary examination of food web structure of Nicola Lake (Taim Hydrological System, south Brazil) using dual C and N stable isotope analyses
Authors: Garcia Alexandre M. , Hoeinghaus David J. , Vieira João P. , Winemiller Kirk O. , Marques David M. L. Motta , Bemvenuti Marlise A.
Published: December 2007

Taim Ecological Reserve is located within the Taim Hydrological System and was created to protect a heterogeneous and productive landscape harboring exceptional biological diversity in southern Brazil. Using stable isotope ratio analyses of carbon (delta13C) and nitrogen (delta15N), we provide a preliminary description of the food web structure, including estimates of production sources supporting fish populations and vertical trophic structure, within a representative lake of this system. A total of 21 organisms (5 macrophytes, 3 mollusks and 13 adult fishes) representing 16 species were collected for isotope analysis. Fishes had delta13C values ranging from -24.30º/oo to -28.31º/oo , showing concordance with the range of values observed for macrophytes (-25.49 to -27.10º/oo), and suggesting that these plants could be a major carbon source supporting these fishes. delta13C signatures of Corbicula (-30.81º/oo) and Pomacea (-24.26º/oo) indirectly suggest that phytoplankton and benthic algae could be alternative carbon sources for some consumers. Nitrogen isotope ratios indicated approximately three consumer trophic levels. The pearl cichlid Geophagus brasiliensis was a primary consumer. Two catfishes (Trachelyopterus lucenai and Loricariichthys anus) were secondary consumers. Two congeneric pike cichclids (Crenicichla lepidota and C. punctata), a catfish (Pimelodus maculatus) and the characids Astyanax fasciatus and Oligosarcus robustus were tertiary consumers. Further studies including additional primary producers and consumers and greater sample numbers should be conducted to provide a more complete and detailed description of food web structure and dynamics within the reserve.
Ambicolored specimens of the flounder Paralichthys orbignyanus (Pleuronectiformes: Paralichthyidae)
Authors: Carnikián Agustín , Acuña Alicia , Viana Federico
Published: December 2007

Two ambicolored specimens of Paralichthys orbignyanus were reported for the estuarine area of the arroyo Pando (Uruguay). One of the specimens showed an almost fully coloration on the blind side, excepting the cephalic region, while the other one was partially pigmented. This is the first record of ambicoloration in P.orbignyanus.
Ambicoloration and morphological aberration in the sole Achirus declivis (Pleuronectiformes: Achiridae) and two other cases of color abnormalities in achirid soles from southeastern Brazil
Authors: Macieira Raphael Mariano , Joyeux Jean-Christophe , Chagas Leandro Pereira
Published: December 2007

Three cases of color abnormalities and one of morphological aberration in flatfishes of the genus Achirus are described from the Piraquê-Açú River estuary, Espírito Santo, Brazil. One specimen of A. declivis has 75% of the blind side with coloration like that of the ocular side. Another specimen of the same species is strongly hypomelanistic. A third specimen has incomplete eye rotation and a hooked dorsal fin. An ambicolored A. lineatus is also described.
A portable bio-amplifier for electric fish research: design and construction
Authors: Wells Jonathan K. , Crampton William G. R.
Published: December 2007

The weak electric organ discharges (EODs) of gymnotiform knife fishes can be readily amplified with a wideband amplifier connected to submerged electrodes. The output from such an amplifier can then be monitored with audio speakers or digitized for subsequent analysis. Commercially available devices are expensive and usually require mains electrical power. Here we provide design notes and instructions for the construction and calibration of a cheap, portable, battery-powered, AC-coupled wideband bio-amplifier. This device was designed to allow electric fishes to be located in the field, and also to permit the relatively noise-free acquisition of EOD waveforms from specimens held in temporary captivity. This contribution is intended to encourage students of neotropical ichthyology to explore electric signaling in gymnotiform fishes.
HIERARCHICAL REGULATION OF NITROGEN EXPORT FROM URBAN CATCHMENTS: INTERACTIONS OF STORMS AND LANDSCAPES
Authors: Lewis David Bruce , Grimm Nancy B.
Published: December 2007

In urban catchments of arid central Arizona, we investigate how the export of mineral and organic nitrogen (N) in storm runoff is regulated by interactions between local landscape characteristics and broader scale storm features. First, we test whether N export is more a function of (1) processes that affect N concentration in runoff or (2) the propensity of the catchment to convey rainfall as runoff. With data pooled across catchments, the mass of N in export (load) is determined by processes regulating runoff N concentration. There are exceptions when catchments are examined individually, where N load from some catchments is determined by the hydrologic responsiveness of the catchment. Second, we investigate the relationship between N export and catchment features. Loads per catchment area were greater from more impervious catchments, probably because impervious catchments held more N in a mobilizable phase and conveyed more rainfall as overland flow. Loads per area were lower from larger catchments, possibly owing to more N‐retention hot spots in larger catchments. Catchments with the greatest N exports were those with commercial land use, and loads decreased as development became less prevalent or as residential replaced industrial land use. Third, we investigated how catchment features moderated direct responses of N export to storms. Export was less correlated with storm features in catchments that were larger, more pervious, and less industrial. Results support an “N build and flush” hypothesis, which purports that there is little biotic processing of N deposited to arid, urban surfaces with little organic matter. The rate and duration of deposition determine the size of the mobile N pool. Any amount of rainfall capable of generating overland flow would entrain nearly all mobilizable N and export it from the catchment. Nonetheless, these results suggest that, even with daunting seasonal and interannual variability in storm conditions, material export can be reduced by managing intrinsic catchment features.
PATCH NETWORK CRITERIA FOR DISPERSAL‐LIMITED ENDEMIC BIRDS OF SOUTH AMERICAN TEMPERATE RAIN FOREST
Authors: Castellón Traci D. , Sieving Kathryn E.
Published: December 2007

We developed a set of simple empirically based criteria for distinguishing forest patch configurations that we expected to support persistent populations of two endemic Tapaculo species with limited dispersal ability (Chucao Tapaculos [Scelorchilus rubecula] and Black‐throated Huet‐huets [Pteroptochos tarnii]) in South American temperate rain forest. The criteria address sustainable population sizes (tested using population viability analysis), habitat area needed to support sustainable populations, and measures of functional connectivity derived from radiotelemetry data and patch occupancy models. We then applied the criteria in three real‐world demonstration landscapes, first, to predict numbers of breeding territories potentially accommodated within patch configurations and, second, to evaluate increases that might be achieved if landscape connections among isolated patches were restored (e.g., using corridors). The best connected of the three demonstration landscapes was predicted to support large sustainable populations without intervention to restore connectivity, whereas none of the patch configurations was sustainable in the most fragmented landscape, with or without corridor restoration. Notably, however, corridor restoration in the landscape with an intermediate fragmentation level was expected to quadruple the sustainable Chucao population and potentially prevent regional Huet‐huet extinction. Thus, our network criteria provide a simple approach for developing and evaluating spatially explicit prescriptions for conservation planning in this highly endangered biome. The criteria may be especially useful for discriminating among landscapes where restoration of connectivity is, or is not, an appropriate course of action.
ROBUST POPULATION MANAGEMENT UNDER UNCERTAINTY FOR STRUCTURED POPULATION MODELS
Authors: Deines A. , Peterson E. , Boeckner D. , Boyle J. , Keighley A. , Kogut J. , Lubben J. , Rebarber R. , Ryan R. , Tenhumberg B. , Townley S. , Tyre A. J.
Published: December 2007

Structured population models are increasingly used in decision making, but typically have many entries that are unknown or highly uncertain. We present an approach for the systematic analysis of the effect of uncertainties on long‐term population growth or decay. Many decisions for threatened and endangered species are made with poor or no information. We can still make decisions under these circumstances in a manner that is highly defensible, even without making assumptions about the distribution of uncertainty, or limiting ourselves to discussions of single, infinitesimally small changes in the parameters. Suppose that the model (determined by the data) for the population in question predicts long‐term growth. Our goal is to determine how uncertain the data can be before the model loses this property. Some uncertainties will maintain long‐term growth, and some will lead to long‐term decay. The uncertainties are typically structured, and can be described by several parameters. We show how to determine which parameters maintain long‐term growth. We illustrate the advantages of the method by applying it to a Peregrine Falcon population. The U.S. Fish and Wildlife Service recently decided to allow minimal harvesting of Peregrine Falcons after their recent removal from the Endangered Species List. Based on published demographic rates, we find that an asymptotic growth rate λ > 1 is guaranteed with 5% harvest rate up to 3% error in adult survival if no two‐year‐olds breed, and up to 11% error if all two‐year‐olds breed. If a population growth rate of 3% or greater is desired, the acceptable error in adult survival decreases to between 1% and 6% depending of the proportion of two‐year‐olds that breed. These results clearly show the interactions between uncertainties in different parameters, and suggest that a harvest decision at this stage may be premature without solid data on adult survival and the frequency of breeding by young adults.
AMPHIBIAN OCCURRENCE IS INFLUENCED BY CURRENT AND HISTORIC LANDSCAPE CHARACTERISTICS
Authors: Piha Henna , Luoto Miska , Merilä Juha
Published: December 2007

Human‐induced habitat loss and degradation are major threats to wetland species as reflected in the fact that wetlands have declined by more than 50% in Europe and North America during the last century. Both current and historic land‐use patterns are likely to be significant determinants of wetland species' distributions; however their relative importance is often unknown. We studied the importance of local (study pond) and landscape (current and 18th‐century landscape) characteristics in explaining the occurrence and species richness of amphibians (Rana arvalis, Bufo bufo, and Triturus vulgaris) on the Swedish island of Gotland, where more than 40% of wetlands have been lost since the 18th century. Current local habitat characteristics were the strongest determinants of occurrence for all study species. Additionally, species occurrence was related to current and historic landscape characteristics, which generally explained equal amounts of the variation in species‐occurrence data. The proportions of both current and historic arable land were negative determinants of amphibian occurrence and species richness, indicating that agricultural land use may have an overall negative impact on amphibians, and that amphibians may occur less frequently in areas with a long agricultural history. Likewise, historic forest area was positively related to B. bufo occurrence and species richness, whereas current forests had no significant effects, suggesting that there may be a lag in the response of amphibians to agriculture‐mediated habitat loss. Our results suggest that historic land‐use patterns may influence current amphibian populations and that inclusion of historic land‐use information could be a valuable tool in future studies on amphibian–habitat relations.
SPATIAL PATTERNS OF FOREST CHARACTERISTICS IN THE WESTERN UNITED STATES DERIVED FROM INVENTORIES
Authors: Hicke Jeffrey A. , Jenkins Jennifer C. , Ojima Dennis S. , Ducey Mark
Published: December 2007

In the western United States, forest ecosystems are subject to a variety of forcing mechanisms that drive dynamics, including climate change, land‐use/land‐cover change, atmospheric pollution, and disturbance. To understand the impacts of these stressors, it is crucial to develop assessments of forest properties to establish baselines, determine the extent of changes, and provide information to ecosystem modeling activities. Here we report on spatial patterns of characteristics of forest ecosystems in the western United States, including area, stand age, forest type, and carbon stocks, and comparisons of these patterns with those from satellite imagery and simulation models. The USDA Forest Service collected ground‐based measurements of tree and plot information in recent decades as part of nationwide forest inventories. Using these measurements together with a methodology for estimating carbon stocks for each tree measured, we mapped county‐level patterns across the western United States. Because forest ecosystem properties are often significantly different between hardwood and softwood species, we describe patterns of each. The stand age distribution peaked at 60–100 years across the region, with hardwoods typically younger than softwoods. Forest carbon density was highest along the coast region of northern California, Oregon, and Washington and lowest in the arid regions of the Southwest and along the edge of the Great Plains. These results quantify the spatial variability of forest characteristics important for understanding large‐scale ecosystem processes and their controlling mechanisms. To illustrate other uses of the inventory‐derived forest characteristics, we compared them against examples of independently derived estimates. Forest cover compared well with satellite‐derived values when only productive stands were included in the inventory estimates. Forest types derived from satellite observations were similar to our inventory results, though the inventory database suggested more heterogeneity. Carbon stocks from the Century model were in good agreement with inventory results except in the Pacific Northwest and part of the Sierra Nevada, where it appears that harvesting and fire in the 20th century (processes not included in the model runs) reduced measured stand ages and carbon stocks compared to simulations.
UNDERSTANDING ABUNDANCE PATTERNS OF A DECLINING SEABIRD: IMPLICATIONS FOR MONITORING
Authors: Kissling Michelle L. , Reid Mason , Lukacs Paul M. , Gende Scott M. , Lewis Stephen B.
Published: December 2007

The Kittlitz's Murrelet (Brachyramphus brevirostris) is a rare, non‐colonial seabird often associated with tidewater glaciers and a recent candidate for listing under the Endangered Species Act. We estimated abundance of Kittlitz's Murrelets across space and time from at‐sea surveys along the coast of Alaska (USA) and then used these data to develop spatial models to describe abundance patterns and identify environmental factors affecting abundance. Over a five‐week period in the summer of 2005, we recorded 794 Kittlitz's Murrelets, 16 Marbled Murrelets (B. marmoratus), and 70 unidentified murrelets. The overall population estimate (N, mean ± SE) during the peak period (3–9 July) was 1317 ± 294 birds, decreasing to 68 ± 37 by the last survey period (31 July–6 August). Density of Kittlitz's Murrelets was highest in pelagic waters of Taan Fjord (18.6 ± 7.8 birds/km2, mean ± SE) during 10–16 July. Spatial models identified consistent “hotspots” of Kittlitz's Murrelets, including several small areas where high densities of murrelets were found throughout the survey period. Of the explanatory variables that we evaluated, tidal current strength influenced murrelet abundance most consistently, with higher abundance associated with strong tidal currents. Simulations based on the empirically derived estimates of variation demonstrated that spatial variation strongly influenced power to detect trend, although power changed little across the threefold difference in the coefficient of variation on detection probability. We include recommendations for monitoring Kittlitz's Murrelets (or other marine species) when there is a high degree of uncertainty about factors affecting abundance, especially spatial variability.
GENETIC MECHANISMS OF POLLUTION RESISTANCE IN A MARINE INVERTEBRATE
Authors: Galletly Bronwyn C. , Blows Mark W. , Marshall Dustin J.
Published: December 2007

Pollution is a common stress in the marine environment and one of today's most powerful agents of selection, yet we have little understanding of how anthropogenic toxicants influence mechanisms of adaptation in marine populations. Due to their life history strategies, marine invertebrates are unable to avoid stress and must adapt to variable environments. We examined the genetic basis of pollution resistance across multiple environments using the marine invertebrate, Styela plicata. Gametes were crossed in a quantitative genetic breeding design to enable partitioning of additive genetic variance across a concentration gradient of a common marine pollutant, copper. Hatching success was scored as a measure of stress resistance in copper concentrations of 0, 75, 150, and 350 μg/L. There was a significant genotype × environment interaction in hatching success across copper concentrations. Further analysis using factor analytic modeling confirmed a significant dimension of across‐environment genetic variation where the genetic basis of resistance to stress in the first three environments differed from that in the environment of highest copper concentration. A second genetic dimension further differentiated between the genetic basis of resistance to low and high stress environments. These results suggest that marine organisms use different genetic mechanisms to adapt to different levels of pollution and that the level of genetic variation to adapt to intense pollution stresses may be limited.
EFFECTS OF RESTORATION AND REFLOODING ON SOIL DENITRIFICATION IN A LEVEED MIDWESTERN FLOODPLAIN
Authors: Orr Cailin H. , Stanley Emily H. , Wilson Karen A. , Finlay Jacques C.
Published: December 2007

River floodplains have the potential to remove nitrate from water through denitrification, the anaerobic microbial conversion of nitrate to nitrogen gas. An important factor in this process is the interaction of river water with floodplain soil; however, many rivers have been disconnected from their historic floodplains by levees. To test the effect of reflooding a degraded floodplain on nitrate removal, we studied changes in soil denitrification rates on the Baraboo River floodplain in Wisconsin, USA, as it underwent restoration. Prior to this study, the site had been leveed, drained, and farmed for more than 50 years. In late fall 2002, the field drainage system was removed, and a gate structure was installed to allow controlled flooding of this site with river water. Soil moisture was extremely variable among zones and months and reflected local weather. Soil organic matter was stable over the study period with differences occurring along the elevation gradient. High soil nitrate concentrations occurred in dry, relatively organic‐poor soil samples and, conversely, all samples with high moisture soils characterized by low nitrate. We measured denitrification in static cores and potential denitrification in bulk samples amended with carbon and nitrogen, one year before and two years following the manipulation. Denitrification rates showed high temporal and spatial variability. Static core rates of individual sites ranged widely (from 0.00 to 16.7 μg N2O‐N·[kg soil]−1·h−1, mean ± SD = 1.10 ± 3.02), and denitrification enzyme activity (DEA) rates were similar with a slightly higher mean (from 0.00 to 15.0 μg N2O‐N·[kg soil]−1·h−1, 1.41 ± 1.98). Denitrification was not well‐correlated with soil nitrate, organic matter content, or moisture levels, the three parameters typically thought to control denitrification. Static core denitrification rates were not significantly different across years, and DEA rates decreased slightly the second year after restoration. These results demonstrate that restored agricultural soil has the potential for denitrification, but that floodplain restoration did not immediately improve this potential. Future floodplain restorations should be designed to test alternative methods of increasing denitrification.
MULTI‐TROPHIC INVASION RESISTANCE IN HAWAII: BIOACOUSTICS, FIELD SURVEYS, AND AIRBORNE REMOTE SENSING
Authors: Boelman Natalie T. , Asner Gregory P. , Hart Patrick J. , Martin Roberta E.
Published: December 2007

We used airborne imaging spectroscopy and scanning light detection and ranging (LiDAR), along with bioacoustic recordings, to determine how a plant species invasion affects avian abundance and community composition across a range of Hawaiian submontane ecosystems. Total avian abundance and the ratio of native to exotic avifauna were highest in habitats with the highest canopy cover and height. Comparing biophysically equivalent sites, stands dominated by native Metrosideros polymorpha trees hosted larger native avian communities than did mixed stands of Metrosideros and the invasive tree Morella faya. A multi‐trophic analysis strongly suggests that native avifauna provide biotic resistance against the invasion of Morella trees and exotic birds, thus slowing invasion “meltdowns” that disrupt the functioning of native Hawaiian ecosystems.
ISOTOPIC EVIDENCE FOR IN‐LAKE PRODUCTION OF ACCUMULATING NITRATE IN LAKE SUPERIOR
Authors: Finlay Jacques C. , Sterner Robert W. , Kumar Sanjeev
Published: December 2007

A century‐long increase in nitrate (NO3−) in the water column of Lake Superior is a classic example of recent nitrogen accumulation in ecosystems, but its cause and relationship to historical NO3− deposition is unknown. We used stable isotope ratios of oxygen and nitrogen in nitrate (δ18O‐NO3 and δ15N‐NO3) to examine its sources in this large lake, which represents 10% of the world's surficial liquid freshwater. The most parsimonious hypothesis to explain the rise in NO3− is that the lake is accruing NO3− deposited directly on the lake surface because it is too unproductive to completely assimilate all of it. Data for δ18O‐NO3 in external sources and the water column, however, are inconsistent with this hypothesis. Instead, the isotopic evidence indicates strongly that the accumulating NO3− is almost entirely derived from nitrification occurring within the lake. While increases in atmospheric deposition of NO3− may have played a role in its buildup in the lake, other factors such as increases in NH4+ and dissolved organic nitrogen inputs from precipitation or rivers, increases in nitrogen fluxes from the sediments, and decreases in burial rates must also be considered as potential drivers of rising NO3−. The sustained accumulation of nitrogen in Lake Superior is thus more complex and incompletely understood than previously assumed.
Video Papers — A Means for Documenting Practitioners' Reflections on Practical Experiences: The Story of Two Teacher Educators
Authors: Smith Kari , Krumsvik Rune
Published: December 2007

This article is documentation of the personal professional reflection processes as well as staff discussions reflecting the staff's ongoing efforts to improve the quality of teaching in the teacher education programme at the University of Bergen. The documentation is two-dimensional: video clips have been inserted into the traditional text form. This allows the reader to personally view the discussed issues and thus better form a personal opinion of the situation, without having to rely solely on written documentation and the authors' subjective analysis. The authors claim is that video-paper as a form for publication allows for a more comprehensive presentation of the data and enables the reader to examine the documentation on which the authors base their reflections and discussions. The validity of the findings is improved as they are open to examination by a wider audience.
Corruption in Higher Education: Conceptual Approaches and Measurement Techniques
Authors: Osipian Ararat L.
Published: December 2007

Corruption is a complex and multifaceted phenomenon. Forms of corruption are multiple. Measuring corruption is necessary not only for getting ideas about the scale and scope of the problem, but for making simple comparisons between the countries and conducting comparative analysis of corruption. While the total impact of corruption is indeed difficult to measure and even more so internal changes in corruption, some aspects of corruption may be quantified and measured. This article presents major conceptual approaches to corruption and develops a technique for measuring the distribution of graft in a higher education industry by using some ideas about bribery and other forms of corruption among the faculty members in higher education institutions in transition and developing nations. In order to measure the level of corruption and its changes over time or changes due to government intervention and other anticorruption efforts, the author combines two indicators, namely the number of corrupt faculty members who take bribes in a given period of time and the value of the average bribe, calculated as weighted average. The author also introduces the Distribution index (DI), the weighted DI, and the share weighted DI in order to capture internal changes in the distribution of graft. The proposed methodology may be applied in measuring corruption in higher education across the nations and making comparisons.
Assurance versus Insurance: A Study of Consumer Receptiveness in an E-Commerce Setting
Authors: Boo El'fred , Low Kin-Yew , Soh Xinming , Lim Miaoling
Published: December 2007

Periodic examination is a critical feature for assurance but not insurance; accordingly insurance is potentially a lower-cost alternative to assurance. Unlike assurance, however, whether insurance inspires consumer confidence remains an unexplored empirical question. This paper compares consumer receptiveness to the concepts of assurance and insurance in an e-commerce setting. Results (n = 360) in a controlled experiment indicate equivalent consumer receptiveness to assurance and insurance; both significantly increase purchasing intention. Results further indicate that consumer preference for CPA versus non-CPA insurance providers depends on consumers' assurance knowledge. High-assurance knowledge consumers prefer insurance provided by insurance companies while low-assurance knowledge consumers prefer insurance provided by CPA firms. Our finding suggests that the CPA profession could potentially leverage its brand name in a service area outside the profession's traditional markets. An extension to our study assesses the feasibility of CPAs providing insurance service solely or in collaboration with insurance companies.
Anticipatory Reporting Standards
Authors: Christensen John , Demski Joel S.
Published: December 2007

The Conceptual Framework offers an approach to understanding and managing reporting choices and their regulation. Qualitative characteristics of the underlying information, in terms of an unrelenting focus on relevance and reliability to the exclusion of particular interests or transaction motives, is a cornerstone of the Framework. We argue that the focus on qualitative characteristics precludes a focus on first-order economic fundamentals and, in the process, invites a static view of reporting standards, as opposed to one based on anticipation of their effect.
Were Former Andersen Clients Treated More Leniently Than Other Clients? Evidence from Going-Concern Modified Audit Opinions
Authors: Krishnan Jagan , Raghunandan K. , Yang Joon S.
Published: December 2007

In the wake of the collapse of Enron and Andersen, several questions were raised about Enron's accounting and the behavior of its auditor. An important question is whether ex-Andersen's clients received more conservative treatment by their new auditors, either due to a greater perceived litigation risk because of their previous association with Andersen or because of a “correction” of alleged lax auditing by Andersen. We examine going-concern modified audit opinions for former clients of Arthur Andersen, and compare them with opinions issued for other newly acquired clients. We find that auditors were less likely to issue going-concern modified audit opinions to small clients who switched from Andersen than to their existing clients. However, this trend reverses with an increase in client size, with large former Andersen clients more likely to receive going-concern opinions. Our results are consistent with suggestions that increased litigation risk associated with the larger ex-Andersen clients led to increased conservatism by the new auditors. We conjecture that the reduced conservatism for the smaller ex-Andersen clients is likely due to high ex ante conservatism of the Big 4 in not accepting clients perceived to be risky.
Auditor Independence: Evidence on the Joint Effects of Auditor Tenure and Nonaudit Fees
Authors: Gul Ferdinand A. , Jaggi Bikki L. , Krishnan Gopal V.
Published: December 2007

This study examines whether the impact of nonaudit fees on auditor independence is contingent on auditor tenure. The results, based on a sample of 4,720 U.S. firms for the years 2000 and 2001, show that there is a positive association between nonaudit fees and positive discretionary current accruals, a proxy for auditor independence, for firms with short auditor tenure of not more than three years. These findings suggest that nonaudit fees may impair auditor independence when auditor tenure is short and not when auditor tenure is long. Furthermore, exploratory analyses show that the positive association between nonaudit fees and earnings management for firms with short auditor tenure is significant for small clients but not for large clients. Taken together, these results suggest that the association between nonaudit fees and auditor independence is contingent upon auditor tenure, and that high nonaudit fees have a negative impact on auditor independence when audit tenure is short and client firm size is small.
Engagement Quality Reviews: A Comparison of Audit Firm Practices
Authors: Epps Kathryn K. , Messier William F.
Published: December 2007

Engagement quality (concurring partner) review is an important part of the audit review process. It is one quality control mechanism used by public accounting firms to monitor the quality of audit engagements. The engagement quality reviewer serves as an evaluator of the performance of the engagement partner and engagement team. Concerns about the effectiveness of existing firm concurring partner review practices have led to increased partner sanctions imposed by the Securities and Exchange Commission (SEC). In addition, Section 103 of the Sarbanes-Oxley Act of 2002 directs the Public Company Accounting Oversight Board (PCAOB) to develop an auditing standard on engagement quality review. This practice note reports on an analysis of six major firms' written guidance and practice aids for engagement quality review. Our comparison of the firms' guidance shows some differences in the assignment of engagement quality reviewer, the participation of the engagement quality reviewer in audit planning, the extensiveness of practice aids, and the involvement of engagement quality reviewer during the course of audit engagements. Lastly, we identify a number of research questions and practice implications.
Spending Patterns with Lapsing Budgets: Evidence from U.S. Army Hospitals
Authors: Balakrishnan Ramji , Soderstrom Naomi S. , West Timothy D.
Published: December 2007

We explore how the practice of reverting unused funds (budget lapsing) affects intra- and inter-year spending patterns. Data from 31 army hospitals over a period of five years provide strong support for a saving-dissaving model. Hospital administrators appear to stockpile pharmaceuticals and other supplies toward the end of a fiscal year, leading to a significant spike in spending that potentially exhausts their budget. Interestingly, data show a decline at the start of the next fiscal year that is larger than the preceding spike, indicating that mangers build a reserve for later use. The magnitude of the reserve accumulated at the start of a year is reliably persistent across years and accelerates the upward trend in spending through the year. That is, managers increasingly expend the reserve as environmental uncertainty decreases.We conclude that risk-aversion plays a significant role in determining intra-year trends.
Budget Adjustments in Response to Spending Variances: Evidence of Ratcheting of Local Government Expenditures
Authors: Lee Tanya M. , Plummer Elizabeth
Published: December 2007

This paper examines the degree to which government administrators incorporate prior year spending variances into current year budgets. Government administrators have incentives to increase their budgets, and constraints on government spending are weaker than those found in the private sector. Therefore, we expect budget increases associated with prior year government overspending (actual exceeds budget) to be larger than decreases associated with underspending of the same amount. This differential response is called ratcheting. We examine budgets for 1,034 Texas school districts (1995 through 2002), and find budget ratcheting in operating expenditures and the subcategories of instructional and non-instructional expenditures. Ratcheting is most pronounced for non-instructional expenditures. We also find that budget ratcheting is more pronounced when controls on government spending are likely to be weaker. Specifically, budget ratcheting is more pronounced for school districts that operate in a less competitive environment and for districts that have less voter influence.
Gaze Control and Foot Kinematics During Stair Climbing: Characteristics Leading to Fall Risk in Progressive Supranuclear Palsy
Authors: Di Fabio Richard P , Zampieri Cris , Tuite Paul
Published: December 2007

Background and Purpose

Does gaze control influence lower-extremity motor coordination in people with neurological deficits? The purpose of this study was to determine whether foot kinematics during stair climbing are influenced by gaze shifts prior to stair step initiation.

Subjects and Methods

Twelve subjects with gaze palsy (mild versus severe) secondary to progressive supranuclear palsy were evaluated during a stair-climbing task in a cross-sectional study of mechanisms influencing eye-foot coordination. Infrared oculography and electromagnetic tracking sensors measured eye and foot kinematics, respectively. The primary outcome measures were vertical gaze fixation scores, foot lift asymmetries, and sagittal-plane foot trajectories.

Results

The subjects with severe gaze palsy had significantly lower lag foot lift relative to lead foot lift than those with a mild form of gaze palsy. The lag foot trajectory for the subjects with severe gaze palsy tended to be low, with a heading toward contact with the edge of the stair. Subjects with severe gaze palsy were 28 times more likely to experience “fixation intrusion” (high vertical gaze fixation score) during an attempted shift of gaze downward than those with mild ocular motor deficits (odds ratio [OR]=28.3, 95% confidence interval [CI]=6.4–124.8). Subjects with severe gaze shift deficits also were 4 times more likely to have lower lag foot lift with respect to lead foot lift than those with mild ocular motor dysfunction (OR=4.0, 95% CI=1.7–9.7).

Discussion and Conclusion

The small number of subjects and the variation in symptom profiles make the generalization of findings preliminary. Deficits in gaze control may influence stepping behaviors and increase the risk of trips or falls during stair climbing. Neural and kinematic hypotheses are discussed as possible contributing mechanisms.
Multiple hemangiomas in a patient with a t(3q;4p) translocation: An infrequent association with Wolf–Hirschhorn syndrome
Authors: Pardo Sherly , Blitman Netta , Han Bokyung , Cohen Ninette , Edelmann Lisa , Hirschhorn Kurt
Published: December 2007

We report on the clinical phenotype of an infant with a duplication of the terminal portion of the long arm of chromosome 3(q26.3‐qter) and a deletion of the terminal portion of the short arm of chromosome 4(p16.3) with multiple hemangiomas and a hamartoma. Patients with deletions of distal 4p have the characteristic features of Wolf–Hirschhorn syndrome (WHS); whereas those with the distal duplication of 3q have a well recognized syndrome with some features resembling Cornelia‐de Lange syndrome (CdLS). Neither of these recognized chromosomal anomalies has been reported previously to be associated with multiple hemangiomas or other vascular malformations. © 2007 Wiley‐Liss, Inc.
Diagnosis of a terminal deletion of 4p with duplication of Xp22.31 in a patient with findings of Opitz G/BBB syndrome and Wolf–Hirschhorn syndrome
Authors: So Joyce , Müller Ines , Kunath Melanie , Herrmann Susanne , Ullmann Reinhard , Schweiger Susann
Published: December 2007

Opitz G/BBB syndrome (OS) is a congenital midline malformation syndrome characterized by hypertelorism, hypospadias, cleft lip/palate, laryngotracheoesophageal abnormalities, imperforate anus, developmental delay and cardiac defects. The X‐linked form is caused by mutations in the MID1 gene, while no gene has yet been identified for the autosomal dominant form. Here, we report on a 15‐year‐old boy who was referred for MID1 mutation analysis with findings typical of OS, including apparent hypertelorism, hypospadias, a history of feeding difficulties, dysphagia secondary to esophageal arteria lusoria, growth retardation and developmental delay. No MID1 mutation was found, but subsequent sub‐megabase resolution array CGH unexpectedly documented a 2.34 Mb terminal 4p deletion, suggesting a diagnosis of WHS, and a duplication in Xp22.31. Wolf–Hirschhorn syndrome (WHS) is a contiguous gene deletion syndrome involving terminal chromosome 4p deletions, in particular 4p16.3. WHS is characterized by typical facial appearance (“Greek helmet facies”), mental retardation, congenital hypotonia, and growth retardation. While the severity of developmental delay in this patient supports the diagnosis of WHS rather than OS, this case illustrates the striking similarities of clinical findings in seemingly unrelated syndromes, suggesting common or interacting pathways at the molecular and pathogenetic level. This is the first report of arteria lusoria (esophageal vascular ring) in a patient with WHS. © 2007 Wiley‐Liss, Inc.