bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative morphology of the stomach of some laboratory mammals
Authors: Ghoshal N. G. , Bal H. S.
Published: June 2007

Histomorphology of the stomach of mouse, rat, hamster, guineapig, gerbil, and rabbit was studied. Although a common structural basis existed in the stomach between these species, the occurrence and distribution of various cells in gastric glands differed considerably between them. In mice, rats, hamsters and gerbils, the lower one-third of the glandular lamina propria was seemingly occupied by a varying proportion of parietal and chief cells. In rabbits, the predominantly occurring chief cells were distributed in the lower three-quarters of the glands intermingling with parietal cells, but in guineapigs the chief cells were not discernible. In hamsters, there was, however, a gradual increase of chief cells from the junction between nonglandular-glandular stomach toward the pyloric region. In all these species, parietal cells were the predominant cell type in the upper half to upper one-third of the gastric glands, often extending up to the neck of the glands interspersing between mucus neck cells and occasionally between chief cells.
Management of Anthracycline Extravasation Injuries
Authors: Reeves David
Published: June 2007

Objective:

To review the evidence for the management of anthracycline extravasation and determine the optimal treatment of such injuries.

Data Sources:

A search of MEDLINE (1966–February 2007) and International Pharmaceutical Abstracts (1970–February 2007) was performed using the search terms anthracyclines and extravasation.

Data Synthesis:

Extravasation of anthracyclines can have devastating effects. After infiltration of these drugs into the interstitial tissue, damage may range from mild erythema and pain to severe tissue necrosis. Many agents have been studied in the management of these injuries; however, few have demonstrated efficacy and treatment remains controversial. Nonpharmacologic modalities shown to limit extravasation injuries include local tissue cooling and elevation of the affected area. Corticosteroids, sodium bicarbonate, hyaluronidase, hyperbaric oxygen, heparin fractions, α-tocopherol, N-acetylcysteine, and granulocyte macrophage-colony stimulating factor have all either been shown to be ineffective or have limited data supporting their use. Topical dimethyl sulfoxide (DMSO) has been shown in prospective studies to limit the course of extravasation injuries. Dexrazoxane has been shown in animal models and case reports to be useful in the management of anthracycline extravasation. Two recent prospective clinical trials examining intravenous dexrazoxane 1000 mg/m2 within 6 hours of extravasation, 1000 mg/m2 24 hours after extravasation, and 500 mg/m2 48 hours after extravasation injuries add to the data supporting the use of this agent in such injuries. Of the 54 patients enrolled, surgery-requiring necrosis was avoided in 98.2%.

Conclusions:

The optimal treatment of anthracycline extravasation includes local tissue cooling, elevation of the afflicted extremity, dexrazoxane administration, and possibly topical DMSO. Many other drugs have been investigated; however, due to a lack of data, they cannot be recommended for the management of anthracycline extravasation.
Emotion and consciousness in adolescent psychogenic amnesia
Authors: Reinhold Nadine , Markowitsch Hans J.
Published: June 2007

Psychogenic amnesia is characterized by an impaired retrieval process of stored information, while the acquisition of new information is conserved. In addition, patients with this condition may display a state of belle indifférence towards their own situation and may manifest deficits in emotional processing. So far, these conditions were noted cursorily in previous case descriptions, but have not been investigated thoroughly. We report data on two female juvenile patients that were examined with neuropsychological, including remote memory tests. No impairments in cognitive or anterograde mnestic functions but, as expected, severe disturbances in remote memory tests were found. Additionally, we administered tests to assess basic and higher emotional processing functions. Both patients showed evidence of impaired higher and, though to a lesser extent, basic emotional processing skills. Finally, we discuss the contribution of (self‐)consiousness, the current emotional state and emotional processing skills as possible factors, maintaining the condition of psychogenic amnesia.
Irradiation of GAPDH: a model for environmentally induced protein damage
Authors: Voss Peter , Hajimiragha Hossein , Engels Martina , Ruhwiedel Carsten , Calles Christian , Schroeder Peter , Grune Tilman
Published: June 2007

Environmental factors, including sunlight, are able to induce severe oxidative protein damage. The modified proteins are either repaired, degraded or escape from degradation and aggregate. In the present study we tested the effect of different sunlight components such as UV-A, UV-B, and infrared radiation on protein oxidation in vitro. We chose glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a model enzyme and analyzed the irradiation-induced enzyme activity loss, fragmentation and aggregation, and quantified various oxidative amino acid modifications. Since γ-irradiation was used in numerous studies before, we used it for comparative purposes. Infrared radiation was unable to damage GAPDH in the dose range tested (0–1000 J/cm2). UV-A led to a decrease in free thiol content, which was connected with a loss in enzyme activity, while only at very high doses could moderate protein aggregation and fragmentation be observed. UV-B (0–2 J/cm2) and γ-irradiation (0–500 Gy) led to a dose-dependent increase in protein modification. Interestingly, UV-B acted on specific amino acids, such as arginine, proline, and tyrosine, whereas γ-irradiation acted more randomly. The possibility of using the amino acid oxidation pattern as a biomarker of the source of damage is discussed.
Increased carcinogenic potential of myeloid tumor cells induced by aberrant TGF-β1-signaling and upregulation of cathepsin B
Authors: Reisenauer Anita , Eickelberg Oliver , Wille Aline , Heimburg Anke , Reinhold Annegret , Sloane Bonnie F. , Welte Tobias , Bühling Frank
Published: June 2007

The TGF-β signaling pathways are implicated in cancer. Cysteine cathepsins can contribute to the carcinogenic potential of tumor cells. The aim of this study was to investigate the regulation of cysteine cathepsin expression by TGF-β1 and the functional implications in tumor cells. We found an upregulation of cathepsin B (CathB, 2- to 5-fold) in different myeloid tumor cells (THP-1, MonoMac-1, MonoMac-6) after incubation with TGF-β1. No upregulation was found in monocytes, and there was suppression of CathB expression in epithelial tumor cells (A549). Increased cathepsin B activity led to enhanced carcinogenic potential, which was reflected by increased migration and invasion of the cells and resistance to inhibitor-induced apoptosis. Analysis of the TGF-β signaling pathways showed no alterations in TGF-β/BMP receptor expression or SMAD2/3 phosphorylation, and no influence of MAP kinase pathways. However, a reduction in SMAD1 expression was detected. The lack of BMP action on cysteine cathepsin expression in myeloid tumor cells, but not in epithelial tumor cells, suggests a defect in the Smad1/Smad5 pathway. We located a related TGF-β1-responsive element within the first intron of the CathB gene. In conclusion, alterations in the TGF-β1 signaling pathway lead to upregulation of CathB, which contributes to the carcinogenic potential of tumor cells.
Anti-innexin 2 aptamers specifically inhibit the heterologous interaction of the innexin 2 and innexin 3 carboxyl-terminiin vitro
Authors: Knieps Martin , Herrmann Sonja , Lehmann Corinna , Löer Birgit , Hoch Michael , Famulok Michael
Published: June 2007

We recently demonstrated that heteromerization of innexins 2 and 3 fromDrosophila melanogaster(Dm) is crucial for epithelial organization and polarity of the embryonic epidermis. Both innexins are thought to interact via their C-terminal cytoplasmic domains during the assembly of heteromeric gap junction channels. However, the mechanisms that control heteromeric versus homomeric channel formation are still largely unknown. Here we report the isolation of both non-modified and 2′-fluoro-2′-deoxy-modified RNA anti-innexin 2 aptamers byin vitroselection. The aptamers bind to a proximal epitope on the carboxyl-tail ofDminnexin 2 protein and specifically inhibit the heterologous interaction of innexin 2 and innexin 3 carboxyl-terminiin vitro. These domain-specific inhibitors represent the first step towards functional studies focusing on the activity of these domainsin vivo.
Impoliteness, preference organization and conducivity
Authors: Bousfield Derek
Published: June 2007

Traditional approaches to politeness (e. g. Brown and Levinson 1987) and impoliteness (e. g. Culpeper 1996 and Lachenicht 1980), rarely consider the effects of their face-oriented strategies outside of the context of a single turn. While Culpeper, Bousfield and Wichmann (2003) do consider both how impoliteness pans out in extended discourse and the role of prosody in conveying impoliteness, what's not considered are the effects that manipulating or exploiting interactant expectations through the exploitation of specific turn-taking mechanisms can have in the production of impolite face damaging utterances. The broad aim of this paper is to explore the role in impoliteness production of one such mechanism, Preference Organization (see Sacks 1992), which, when coupled with the concept of Conducivity in questions (see Quirk et al. 1985), can give rise to extremely powerful face damaging acts and act sequences. More specifically, the paper will consider and discuss the dynamic verbal interplay between individuals using preference organization and conducivity pragmatically for impolite purposes within such confrontational discourses as car-parking disputes, military training programmes and within restaurant kitchens. The conclusions drawn here with impoliteness will have important implications for politeness theories in particular and for discourse and conflict resolution studies in general.
Cantonese as an additional language in Hong Kong: Problems and prospects
Authors: Sachs Gertrude Tinker , Li David C. S
Published: June 2007

Based on data obtained from a questionnaire survey and in-depth interviews with four Caucasians and four dark-skinned Asians, this study shows that while some ‘foreigners’ do make an effort to learn Cantonese, many find the teaching methods not so useful and the language difficult to master, especially its tone system. The data are analyzed following the interactive multicultural model of acculturation. The findings point toward a huge chasm between non-local groups and the Cantonese-speaking community. The receptivity of Hong Kong Chinese towards attempts by members of non-local groups to speak Cantonese varies, depending on their racial identity and socioeconomic status.
Was motiviert die partielle Unflektiertheit des indefiniten Artikels? Markiertheitstheoretische und sprachhistorische Überlegungen / What motivates the partial uninflectedness of the indefinite article? Markedness-theoretical and languagehistorical considerations
Authors: Bittner Dagmar
Published: June 2007

German noun phrases containing an article realise gender and case inflection on that article. There seems to be only a few exceptions to this rule, e.g., the indefinite article (
Historical Sociolinguistics Network (HiSoN)
Authors: Elspaß Stephan , Langer Nils , Scharloth Joachim , Vandenbussche Wim
Published: June 2007

Die Historische Soziolinguistik hat sich in den letzten 25 Jahren zu einer zentralen Teildisziplin der sprachhistorischen Forschung entwickelt, von der auch wichtige Impulse für die Linguistik der Gegenwartssprache ausgehen. Dennoch sind bislang nur wenige Versuche unternommen worden, den zahlreichen Forschungsansätzen ein gemeinsames Forum zu geben, das einen intensiven Austausch über Theorien und Methoden der Disziplin, aber auch über forschungspraktische Fragen ermöglichen würde. Im vergangenen Jahr wurde auf der Konferenz „Language History from Below“ in Bristol das „Historical Sociolinguistics Network“ (HiSoN) gegründet. HiSoN besteht zur Zeit aus über 100 Wissenschaftlerinnen und Wissenschaftlern aus unterschiedlichen Philologien.
Thiamine and Fatty Acid Content of Walleye Tissue from Three Southern U.S. Reservoirs
Authors: Honeyfield Dale C. , Vandergoot Christopher S. , Bettoli Phillip W. , Hinterkopf Joy P. , Zajicek James L.
Published: June 2007

We determined the thiamine concentration in egg, muscle, and liver tissues of walleyes Sander vitreus and the fatty acid content of walleye eggs from three southern U.S. reservoirs. In two Tennessee reservoirs (Dale Hollow and Center Hill), in which there were alewives Alosa pseudoharengus in the forage base, natural recruitment of walleyes was not occurring; by contrast in Lake James Reservoir, North Carolina, where there were no alewives, the walleye population was sustained via natural recruitment. Female walleye tissues were collected and assayed for thiamine (vitamin B1) and fatty acid content. Thiamine pyrophosphate was found to be the predominant form of thiamine in walleye eggs. In 2000, mean total egg thiamine concentrations were similar among Center Hill, Dale Hollow, and Lake James reservoirs (2.13, 3.14, and 2.77 nmol thiamine/g, respectively). Egg thiamine concentration increased as maternal muscle (r2 = 0.73) and liver (r2 = 0.68) thiamine concentration increased. Walleye egg thiamine does not appear to be connected to poor natural reproduction in Tennessee walleyes. Threadfin shad Dorosoma petenense, which are found in all three reservoirs, had higher thiaminase activity than alewives. Six fatty acids differed among the walleye eggs for the three reservoirs. Two were physiologically important fatty acids, arachidonic acid (20:4(n-6)) and docosahexaenoic acid (22:6(n-3)), which are important eicosanoid precursors involved in the regulation of biological functions, such as immune response and reproduction.
FUZZY MODELING OF CYANOBACTERIAL SURFACE WATERBLOOMS: VALIDATION WITH NOAA‐AVHRR SATELLITE IMAGES
Authors: Ibelings Bas W. , Vonk Marijke , Los Hans F. J. , van der Molen Diederik T. , Mooij Wolf M.
Published: June 2007

Surface waterblooms of toxic cyanobacteria (scums) interfere with the use of lakes, for instance in the production of drinking water or for recreation. Routine monitoring data are not sufficient for early warning due to the large temporal and spatial variability in the occurrence of surface waterblooms, and the time lag between the formation of the scum and the availability of relevant information for risk management. We combined a “traditional” dynamic simulation model based upon differential equations with fuzzy logic to describe the three main conditions governing surface waterbloom formation: (1) a preexisting population of cyanobacteria, (2) buoyancy of the cells, and (3) stability of the water column. The attributes and membership functions of the fuzzy model were based on earlier field studies of diel changes in buoyancy and vertical distribution of cyanobacteria. The model was applied without further calibration to the large lake IJsselmeer (1200 km2) in the Netherlands, and we validated the model output using 12 years of NOAA‐AVHRR (National Oceanic and Atmospheric Administration–Advanced Very High Resolution Radiometers) satellite images on which surface blooms are discernible as an enhanced vegetation index or increased surface water temperature. Existing surface blooms were predicted with high accuracy, but additional blooms were also predicted. A statistical test (Cohen's Kappa) showed that correct predictions of the absence or presence of surface blooms were highly unlikely to have occurred by chance only. The model can be used to predict the occurrence of surface waterblooms in advance on the basis of the long‐term weather forecast, leaving time for appropriate management of the problem. The lake management has expressed interest in converting the present model into a fully operational–online–early warning system.
IMPACT OF HUMAN NUISANCE DISTURBANCE ON VIGILANCE AND GROUP SIZE OF A SOCIAL UNGULATE
Authors: Manor Regev , Saltz David
Published: June 2007

In social ungulates, the proportion of time devoted to vigilance is a function of group size (known as the group size effect). We studied how varying levels of human disturbance influence this function in the mountain gazelle (Gazella gazella) along the southern coastal plain of Israel. Based on current theory, we predicted that changes in the slope of this function should be associated with changes in average group size. In heavily disturbed areas, individual vigilance levels increased in the bigger groups, causing the vigilance vs. group size curve to flatten, i.e., vigilance was high in all group sizes. Consequently, and in accordance with theory, we found a negative relationship between group size and human disturbance. Specifically, we found that in open areas with low disturbance levels, gazelles were in bigger groups than in open areas with high disturbance levels. In social species, the disruption of behavioral patterns by increased human presence can affect their social structure. Because social structure is a key component in the evolution and dynamics of social species, its disruption by human disturbance can have a considerable effect on population performance even if the disturbance does not directly impact survival and reproduction. Social disruption due to increased access to natural areas should be an important consideration in managing fragmented landscapes.
EFFECTS OF METEOROLOGICAL VARIATIONS ON THE CO2 EXCHANGE OF A BRAZILIAN TRANSITIONAL TROPICAL FOREST
Authors: Vourlitis George L. , Priante Filho Nicolau , Hayashi Mauro M. S. , Nogueira José de S. , Raiter Fernando , Hoegel Wander , Campelo, Jr José Holanda
Published: June 2007

The net ecosystem CO2 exchange (NEE) of a 28–30 m tall transitional (ecotonal) tropical forest of the Brazilian Amazon was quantified using tower‐based eddy covariance. Measurements were made between August 1999 and July 2001 and were used to develop nonlinear statistical models to assess daily variations in ecophysiological parameters and provide annual estimates of NEE, gross ecosystem CO2 exchange (GEE), and respiration (Re). Diurnal trends in NEE were correlated with variations in photosynthetic photon flux density (Q), vapor pressure deficit (V), and temperature. Seasonal trends in the CO2‐flux components estimated from nonlinear regression (Amax and R0) were highly correlated with soil water availability and canopy structural properties (LAI and litter production). These results suggest that variations in soil water content can affect rates of canopy photosynthesis and whole forest respiration by altering both physiological processes and canopy structural properties. Estimates of the annual NEE suggest that the forest was in balance with respect to CO2 during the study period, which, in terms of rainfall, was a relatively typical period compared to the 30‐yr average rainfall regime. Our results also suggest that the warmer and dryer microclimate and decline in LAI that accompany land‐cover change will cause transitional forests to be sources of CO2 to the atmosphere.
DETERMINANTS OF REPRODUCTIVE COSTS IN THE LONG‐LIVED BLACK‐LEGGED KITTIWAKE: A MULTIYEAR EXPERIMENT
Authors: Golet Gregory H. , Schmutz Joel A. , Irons David B. , Estes James A.
Published: June 2007

We studied reproductive costs of Black‐legged Kittiwakes (Rissa tridactyla) in Prince William Sound, Alaska (USA) by removing entire clutches from randomly selected nests over four successive years, and then contrasting survival and fecundity of adults from manipulated and unmanipulated nests in each subsequent year. To elucidate mechanisms that lead to the expression of reproductive costs, we simultaneously characterized several behavioral and physiological parameters among adults in the two treatment groups. We also examined naturally nonbreeding adults that previously bred to determine their survival and future nonbreeding probabilities.

Food availability varied during the study, being generally poor at the onset, and improving in later years. Adult nest attendance and body condition (assessed late in the chick‐ rearing period) varied accordingly among years, and between adults raising chicks and adults that had their eggs removed. Adults from unmanipulated nests incurred significant survival costs in all years, although fecundity costs were strongly expressed in only one of four years. Neither survival nor fecundity costs were strongly influenced by body condition or food availability, and no difference in reproductive costs was detected between the sexes. Although unmanipulated breeders survived at lower rates than manipulated breeders due to costs of reproduction, their survival rates were elevated compared to those of natural nonbreeders, presumably due to differences in individual ability. These findings indicate that models of adult survival must consider not only an organism's reproductive state, but also the factors that lead to that state.

Although body condition appeared to be weakly related to survival, it was insufficient to explain the full magnitude of survival costs observed. We suggest that other parameters that were found to differ between treatment groups (e.g., rates of energy turnover, baseline levels of stress, and patterns of allocating body reserves) may be important mechanistic determinants of reproductive costs in kittiwakes, and potentially other long‐lived species. Future efforts should move beyond simple assessments of body condition and toward more integrated measures of physiological condition when attempting to identify factors that influence how long‐lived species balance the costs and benefits of reproduction.
BRIDGING THE GAP: INFLUENCE OF SEED DEPOSITION ON SEEDLING RECRUITMENT IN A PRIMATE–TREE INTERACTION
Authors: Balcomb Sophia R. , Chapman Colin A.
Published: June 2007

Frugivores are thought to influence plant recruitment by creating initial seed deposition templates. However, post‐deposition processes (e.g., predation) may obscure these initial patterns. Few studies have examined successive life‐history stages of animal‐dispersed plants to evaluate how initial frugivore seed deposition influences early life stages of plant recruitment. We addressed this issue by quantifying seed removal and seedling recruitment of Monodora myristica (Annonaceae), a tropical, low‐fecundity, forest tree in Kibale National Park, Uganda. Fruit morphology suggests that this species is dispersed by only the largest arboreal frugivores. We determined which frugivores removed fruit during focal tree watches and quantified seed fate in experiments designed to mimic natural deposition. We estimated stage‐specific transition probabilities of survivorship to seedling establishment and determined expected seedling recruitment from each deposition condition. To evaluate spatial and temporal variation, these methods were conducted at two sites, 15 km apart, over two years. Finally, we compared frugivore abundance between sites to expected seedling and standing seedling, sapling, and pole abundances. We found that large‐bodied primates were critical for seed dispersal. They were the only frugivores that opened the hard‐husked fruits and were estimated to disperse >85% of mature seeds. Seeds placed away from parents had higher germination and establishment probabilities than those under parents, indicating that seed dispersal is advantageous. Single seeds away from parents (mimicking small‐bodied primate seed spitting) had the highest cumulative seedling recruitment probability. However, in three of four site‐by‐year combinations, 86–94% of estimated recruits came from seeds placed in clumps in dung (mimicking large‐bodied primates). High recruitment in the latter condition is due to the large number of seeds estimated to be deposited by large‐bodied primates. Despite this concordance, germination and establishment probabilities were highly variable between sites and years. Germination was a limiting step in recruitment, and high seed mortality from beetles and rodents indicates the importance of predation. The site with higher frugivorous primate abundance had higher standing seedling abundance, but lower expected seedling recruitment and lower sapling and pole abundances. Thus, even in a system where frugivores are critical for dispersal, spatial and temporal variation in post‐deposition processes reduces predictability of frugivore actions on seedling recruitment.

Corresponding Editor: E. S. Menges
LATE‐QUATERNARY VEGETATION DYNAMICS IN NORTH AMERICA: SCALING FROM TAXA TO BIOMES
Authors: Williams John W. , Shuman Bryan N. , Webb Thompson , Bartlein Patrick J. , Leduc Phillip L.
Published: June 2007

This paper integrates recent efforts to map the distribution of biomes for the late Quaternary with the detailed evidence that plant species have responded individualistically to climate change at millennial timescales. Using a fossil‐pollen data set of over 700 sites, we review late‐Quaternary vegetation history in northern and eastern North America across levels of ecological organization from individual taxa to biomes, and apply the insights gained from this review to critically examine the biome maps generated from the pollen data. Higher‐order features of the vegetation (e.g., plant associations, physiognomy) emerge from individualistic responses of plant taxa to climate change, and different representations of vegetation history reveal different aspects of vegetation dynamics. Vegetation distribution and composition were relatively stable during full‐glacial times (21 000– 17 000 yr BP) [calendar years] and during the mid‐ to late Holocene (7000–500 yr BP), but changed rapidly during the late‐glacial period and early Holocene (16 000–8 000 yr BP) and after 500 yr BP. Shifts in plant taxon distributions were characterized by individualistic changes in population abundances and ranges and included large east–west shifts in distribution in addition to the northward redistribution of most taxa. Modern associations such as Fagus–Tsuga and Picea–Alnus–Betula date to the early Holocene, whereas other associations common to the late‐glacial period (e.g., Picea–Cyperaceae–Fraxinus–Ostrya/ Carpinus) no longer exist. Biomes are dynamic entities that have changed in distribution, composition, and structure over time. The late‐Pleistocene suite of biomes is distinct from those that grew during the Holocene. The pollen‐based biome reconstructions are able to capture the major features of late‐Quaternary vegetation but downplay the magnitude and variety of vegetational responses to climate change by (1) limiting apparent land‐cover change to ecotones, (2) masking internal variations in biome composition, and (3) obscuring the range shifts and changes in abundance among individual taxa. The compositional and structural differences between full‐glacial and recent biomes of the same type are similar to or greater than the spatial heterogeneity in the composition and structure of present‐day biomes. This spatial and temporal heterogeneity allows biome maps to accommodate individualistic behavior among species but masks climatically important variations in taxonomic composition as well as structural differences between modern biomes and their ancient counterparts.
BEYOND THEORY TO APPLICATION AND EVALUATION: DIFFUSION APPROXIMATIONS FOR POPULATION VIABILITY ANALYSIS
Authors: Holmes Elizabeth E.
Published: June 2007

Census data on endangered species are often plagued by problems that make quantitative population viability analysis (PVA) a challenge. This paper addresses four such problems: sampling error, density dependence, nonstable age structure, and population supplementation that masks the true population status. Estimating trends and extinction risks using such corrupted data presents serious parameter estimation difficulties. Here I review diffusion approximation (DA) methods for estimating population status and risks from time series data. A variety of parameterization methods are available for DA models; some correct for data corruption and others do not. I illustrate how stochastic Leslie matrix models can be used to evaluate the performance of a proposed DA model and to select among different DA parameterization methods for a given application. Presenting the uncertainty in estimated risks is critical, especially when the data are highly corrupted and estimated parameters are more uncertain. Using a Bayesian approach, I demonstrate how the level of data support for different risk levels can be calculated using DA parameter likelihood functions.
APPLYING SPECIES DIVERSITY THEORY TO LAND MANAGEMENT
Authors: Bestelmeyer Brandon T. , Miller James R. , Wiens John A.
Published: June 2007

Many theories, hypotheses, and empirical studies seek to explain patterns of species richness, turnover, and distribution/abundance (i.e., diversity patterns) at various scales, but it is often not clear how these ideas relate to one another, or how they apply across scales. Consequently, it has been difficult to use diversity theory as a basis for understanding patterns at the intermediate (landscape) scales at which biodiversity is managed. Here, we present a framework for the study and management of diversity based on the ecological processes that influence the distribution of species at different scales. We use this framework to organize diversity theories into several classes based upon how the theories link patterns of habitat occupancy, landscape distribution, and geographic range for a variety of taxa. The processes contributing to diversity patterns depend on the characteristics of the taxa considered, the spatial scales at which organisms respond to environment, and the scales and other characteristics of the particular environments in which investigators hope to explain variation in diversity. At the scales traditionally considered by land managers and conservation biologists, biodiversity is determined by processes addressed by several bodies of theory. Of necessity, management decisions aimed at biodiversity as a whole are based either implicitly or explicitly on only a subset of biodiversity (e.g., single species or functional groups). We suggest that the translation of diversity theory into conservation practice can be achieved, at present, by considering a set of questions for each case: (1) which groups of organisms will be considered, (2) how do their domains of scale relate to the land area under consideration, (3) what processes are likely to be important determinants of species distribution at management scales, and (4) how will the proposed management activities interact with these processes? We illustrate this process using an example from the Chihuahuan Desert. We emphasize the value of considering species diversity theories in a pluralistic and case‐specific way.
CONSEQUENCES OF HYPOXIA ON ESTUARINE ECOSYSTEM FUNCTION: ENERGY DIVERSION FROM CONSUMERS TO MICROBES
Authors: Baird Daniel , Christian Robert R. , Peterson Charles H. , Johnson Galen A.
Published: June 2007

As in other eutrophied estuaries and coastal embayments, persistent hypoxia now routinely develops during summer in the mesohaline portion of the Neuse River estuary (North Carolina, USA). In response to interannual differences in hydrography, summer 1997 exhibited much more intense and widespread hypoxia than summer 1998, permitting inferences about impacts of hypoxia on food web dynamics by comparing system changes across these two summers. The trophic structure of the Neuse estuary now resembles the generic pattern for a degraded temperate estuary with (1) intense planktonic algal blooms and similarly high production of free‐living bacteria, (2) trivial levels of abundance of rooted aquatic plants and benthic macroalgae, (3) depleted apex predators, and (4) functional extinction of the historically dominant benthic grazer, eastern oysters. Detailed carbon‐flow models, based on comprehensive field data, demonstrated large differences between the two summers in trophic transfers and system dynamics. Largely because of greater mortality of benthic invertebrates from more intense hypoxia, total biomass of heterotrophs declined over summer by 51% in 1997 as compared to only 17% in 1998. Because net primary production increased over summer and herbivory in this system is predominantly benthic, the fraction of primary production consumed by herbivores declined over summer by 35% in 1997 and 29% in 1998. Influx of juvenile fishes and their rapid growth in the estuarine nursery over summer led to increases in energy demand by demersal fishes of 380% and 507% in the successive summers. Thus, hypoxia‐enhanced diversion of energy flows into microbial pathways away from consumers and mass mortality of benthic invertebrates from bottom hypoxia occurred at the season of greatest demand by predatory fishes and crabs using the estuary as nursery. Average residence time of carbon in the ecosystem declined by 51% in 1997 and 29% in 1998. Total system throughput declined over summer 1997 while increasing in 1998, indicating the reduced capacity of the system to transfer carbon to higher trophic levels in the more hypoxic summer. Late‐summer trophic pathways were characterized by greater numbers of cycles, but flows became increasingly dominated by microbial loops rather than transfers to consumers. Ecosystem trophic efficiency was only ∼4%, lower than other estuaries similarly analyzed. System properties indicative of resiliency of system function including development capacity, ascendancy, and flow diversity declined over summer 1997, while increasing or declining less in 1998. Thus, intensification of hypoxia caused dramatic reduction in the ecosystem's ability to transfer energy to higher trophic levels and rendered the ecosystem potentially less resilient to other stressors.
USE OF BOUNDARY‐LINE GROWTH PATTERNS AS A BASIS FOR DENDROECOLOGICAL RELEASE CRITERIA
Authors: Black Bryan A. , Abrams Marc D.
Published: June 2007

Identifying releases from suppression represents one of the most fundamental dendroecological procedures for quantifying forest disturbance histories. In tree‐ring series, releases are typically defined as pulses in percent growth change that exceed a minimum threshold. Past methodologies have applied fixed growth‐change thresholds that may overly generalize the ability of a tree to respond to a disturbance event. In this study, we develop a more precise method that scales each release by its maximum release potential as defined by prior growth rates, using an old growth hemlock (Tsuga canadensis L.) forest in central Pennsylvania as an example. On average, tree age, diameter, and crown class appear to influence the magnitude of release response. However, differences in release response between age, diameter, and crown classes are largely an artifact of the more fundamental relationship between release response and growth immediately prior to release. Specifically, maximum percent growth change declines at a steep, negative exponential rate as prior growth levels increase. Slow‐growing hemlocks can exceed 800% growth increases while fast‐growing hemlocks do not exceed growth increases of 20%. This negative exponential threshold, or boundary line, represents the maximum percent growth change that is physiologically possible at a given level of prior growth. Thus, release potential is relative to prior growth rate. This relationship between prior growth and release potential is species specific and is demonstrated in 24 additional hemlock stands. We propose new criteria based on prior growth in which moderate and major releases are those falling within 20–49.9%, and 50–100% of the boundary line, respectively. Effects of short, moderate, and long‐term climate events are mitigated by the percent‐growth‐change calculation and the high growth‐change threshold applied to slow‐growing trees. In addition, we demonstrate that similar boundary lines occur in Pinus strobus L and Quercus prinus L., and interspecific variations in boundary line configuration reflect differences in understory tolerance. Overall, this approach provides a more theoretically sound and flexible approach to developing disturbance histories, and we believe it will ultimately have broad applications in a variety of forest types.
THE “IDIOSYNCRATIC” EFFECT OF A “SENTINEL” SPECIES ON CONTAMINATED ROCKY INTERTIDAL COMMUNITIES
Authors: Fariña J. M. , Castilla J. C. , Ojeda F. P.
Published: June 2007

Depending on their biological characteristics, some species can exert strong (idiosyncratic) effects on ecosystem process. Human impacts on biological communities are related to biodiversity declines but also with species shifts and replacements. In northern Chile, the occurrence of copper mine tailings in seawater is associated with a decrease in the number of sessile species and with rocky intertidal substrate monopolization by one sentinel species, the green ephemeral‐opportunistic algae Entermorpha compressa. In spite of these changes, several consumer species persist on the contaminated sites. In this study, we test the hypothesis that changes in benthic species dominance and composition is associated with an increase in productivity, which affects intertidal consumer abundance, biomass, and/or diversity. We compare benthic species richness, composition, and productivity as well as the abundance, diversity, and diet of consumer species on contaminated and noncontaminated sites. Our results show that changes in community structure at contaminated sites are related to increased primary productivity, the absence of birds, increased abundance of reptiles and crustaceans, and larger body sizes and biomass of some intertidal fishes. The simplified organization of contaminated communities allowed us to demonstrate the importance of species composition in determining the relationship between species richness and productivity in marine systems. The special characteristics of dominance, persistence, and productivity of Enteromorpha compressa (the sentinel species on the contaminated sites) are a clear example of the idiosyncratic effect that some species could have in biological communities.
LINKING SHADE COFFEE CERTIFICATION TO BIODIVERSITY CONSERVATION: BUTTERFLIES AND BIRDS IN CHIAPAS, MEXICO
Authors: Mas Alexandre H. , Dietsch Thomas V.
Published: June 2007

Shade coffee certification programs have emerged over the past six years to verify that coffee marketed as “shade grown” is actually grown on farms that provide higher quality habitat for biodiversity. In spite of good intentions and an increasing market, little consensus exists on whether current criteria can successfully identify coffee farms of conservation significance. This paper provides the first ecological evaluation and comparison of shade‐grown coffee criteria used by major certification programs. Using vegetative data, we evaluated criteria developed by the Rainforest Alliance, the Smithsonian Migratory Bird Center (SMBC), and the Specialty Coffee Association of America across a range of coffee agroecosystems in Chiapas, Mexico, to determine which management practices each program would certify. Fruit‐feeding butterflies and forest bird species found in these coffee agroecosystems were compared with nearby forest reserves as indicators of biodiversity and conservation potential. These agroecosystems fall into three categories: rustic, commercial polyculture, and shaded monoculture. The rustic system contained significantly higher fruit‐feeding butterfly diversity and an avifauna more similar to that found in forest reserves than the other systems. This was also the only agroecosystem that met the criteria for all certification programs, while the shaded monoculture fell short of all sets of criteria. This suggests that certification programs are succeeding in discriminating between the extremes of shade coffee production. Certification programs differed, however, in their treatment of the intermediate, commercial polyculture systems, reflecting different philosophies for conservation in managed ecosystems. Programs promoted by SMBC use high standards that would exclude all but the most diverse commercial polyculture or rustic systems to certify only those systems that support high levels of biodiversity. The program supported by the Rainforest Alliance only excludes the shaded monoculture while engaging the others in the move toward greater sustainability. The merits of each approach should be put to rigorous debate, and their ability to contribute to biodiversity conservation should be reflected in product marketing. This study suggests that further research can provide a stronger scientific basis and independent verification for the certification of green products that claim to enhance biodiversity conservation in tropical agroecosystems.
SEMIARID OLD‐FIELD RESTORATION: IS NEIGHBOR CONTROL NEEDED?
Authors: Wilson Scott D. , Bakker Jonathan D. , Christian Janice M. , Li Xingdong , Ambrose Laura G. , Waddington John
Published: June 2007

Restoration practice suggests that neighbor control is essential in semiarid grasslands, but ecological theory predicts that neighbor effects are relatively small in young fields. We investigated the effectiveness of neighbor control (mowing and herbicide) for establishing native grasses in a recently abandoned field in southwestern Saskatchewan, Canada. We also examined its interactions with common restoration techniques, such as mulching (straw and sawdust) and contrasting sowing methods (drilling, and broadcasting cleaned seeds, cleaning remainders, and native hay). The experiment was repeated over three years to examine the effect of weather. Neighbor control had no effect on establishment and rarely any effect on first‐year survival. This contrasted with significant effects of neighbor control on community and ecosystem‐level variables (species richness, water, N). The lack of neighbor effects is concordant with theory which predicts low competition intensity from ruderal annuals. Establishment in seeded plots varied two‐fold among years in drilled plots and 50‐fold in broadcast plots, and it was lowest during a cool, dry summer. Thus, variables beyond human control are a major factor determining restoration success. Overall, broadcasting was as effective as drilling. The highest long‐term establishment of native species was produced by broadcasting cleaning remainders. Almost no seedlings emerged from plots supplied with native hay. Straw mulch increased soil moisture and available N, and sawdust decreased N, but neither had any long‐term effect on native grasses. Our results suggest that restorations of semiarid old fields should focus less on neighbor control and more on strategies for exploiting suitable years for germination, either by monitoring soil moisture or through repeated seeding.
IMPACTS OF EARLY‐ AND LATE‐SERAL MYCORRHIZAE DURING RESTORATION IN SEASONAL TROPICAL FOREST, MEXICO
Authors: Allen Edith B. , Allen Michael F. , Egerton-Warburton Louise , Corkidi Lea , Gómez-Pompa Arturo
Published: June 2007

Disturbance of vegetation and soil may change the species composition of arbuscular mycorrhizal fungi (AMF), which may in turn affect plant species responses to AMF. Seasonal tropical forest in Mexico is undergoing rapid conversion to early‐successional forest because of increased wildfire and may require restoration. The responses of six early‐ and late‐successional tree species were tested using early‐ and late‐successional AMF inoculum. The plants were germinated in the shadehouse and received three inoculum treatments: (1) soil from a two‐year‐old burned site, (2) soil from a mature forest site, or (3) uninoculated controls. They were transplanted as seedlings to a site prepared by burning, and their growth was measured from September 1997 to November 2000. All six species had the greatest growth response to early‐seral inoculum, but the response to late‐seral inoculum varied. Two tree species, Ceiba pentandra and Guazuma ulmifolia, were smallest with late‐seral inoculum, even smaller than the uninoculated plants, and the other species, Brosimum alicastrum, Havardia albicans, Acacia pennatula, and Leucaena leucocephala, had intermediate growth with late‐seral inoculum. Of these, Brosimum, Havardia, and Ceiba occur in late‐successional forest, and the others are early seral. Of the several growth measurements (height, cover, biomass, stem diameter), stem‐diameter responses to inoculum were still significantly different into the third year for four of the species. The uninoculated plants became infected by residual inoculum in the burned experimental site within three months of transplanting, yet mycorrhizal responses persisted. The treatment size differences may be due to different species composition of the inocula. The early‐seral inoculum was dominated by small‐spored Glomus spp., while the late‐seral inoculum had a higher density of large‐spored Gigasporaceae. The latter are known from greenhouse experiments to promote a smaller plant‐growth response than Glomus. Mature forest trees may withstand the carbon drain from Gigasporaceae better than establishing seedlings, so the growth patterns we observed with inoculum source are consistent with a rapidly growing successional forest, followed by slower‐growing mature forest. The results suggest that early‐seral AMF should be used when seedlings are inoculated for restoration, even for late‐seral tree species.
BEYOND POTENTIAL VEGETATION: COMBINING LIDAR DATA AND A HEIGHT‐STRUCTURED MODEL FOR CARBON STUDIES
Authors: Hurtt George C. , Dubayah Ralph , Drake Jason , Moorcroft Paul R. , Pacala Stephen W. , Blair J. Bryan , Fearon Matthew G.
Published: June 2007

Carbon estimates from terrestrial ecosystem models are limited by large uncertainties in the current state of the land surface. Natural and anthropogenic disturbances have important and lasting influences on ecosystem structure and fluxes that can be difficult to detect or assess with conventional methods. In this study, we combined two recent advances in remote sensing and ecosystem modeling to improve model carbon stock and flux estimates at a tropical forest study site at La Selva, Costa Rica (10°25′ N, 84°00′ W). Airborne lidar remote sensing was used to measure spatial heterogeneity in the vertical structure of vegetation. The ecosystem demography model (ED) was used to estimate the consequences of this heterogeneity for regional estimates of carbon stocks and fluxes. Lidar data provided substantial constraints on model estimates of both carbon stocks and net carbon fluxes. Lidar‐initialized ED estimates of aboveground biomass were within 1.2% of regression‐based approaches, and corresponding model estimates of net carbon fluxes differed substantially from bracketing alternatives. The results of this study provide a promising illustration of the power of combining lidar data on vegetation height with a height‐structured ecosystem model. Extending these analyses to larger scales will require the development of regional and global lidar data sets, and the continued development and application of height structured ecosystem models.