bluuebunny/crossref_metadata_2025_split huggingface dataset:
Positive effects of damselfish override negative effects of urchins to prevent an algal habitat switch
Authors: Irving Andrew D. , Witman Jon D. 
Published: January 2009

Summary

Understanding the factors that influence habitat persistence is a central theme in ecology, particularly for habitats created by terrestrial and aquatic primary producers that are some of the world's most extensive and ecologically important.
Many species have positive (e.g. farming) or negative effects (e.g. herbivory) on the abundance of primary producers, potentially causing wholesale switches in habitat structure if the net outcome of effects moves toward one extreme (e.g. over‐grazing). Predicting the conditions under which such switches occur remains a key challenge for ecologists.
The purpose of this study was to understand how co‐habiting species of opposing effect (damselfish as habitat facilitators vs. sea urchins as habitat consumers) can directly and indirectly influence the persistence of algal habitats on a tropical coast, including their potential to initiate switches among habitat types (productive ‘turfs’ of filamentous algae vs. ‘barrens’ of encrusting algae).
Using a series of five independent experiments, we observed that damselfish facilitated the production of algal turfs both directly, through active farming of selected species, and indirectly, by vigorously attacking and expelling invading urchins from the local area (i.e. preventing herbivory). In contrast, urchins consumed algal turf to directly maintain barrens.
The negative effects of urchins on algal turf were strong enough to initiate a habitat switch from turf to barrens, but this was conditional upon the absence of damselfish and the presence of a particular species of urchin.
Synthesis. These results build upon our understanding of the dynamics of habitat persistence by demonstrating the conditions where biological interactions of opposing direction (positive vs. negative) maintain or switch habitat types. Such knowledge is central to addressing global concerns about habitat loss and predicting the occurrence of switches to less‐productive states.
Detection, survival rates and dynamics of a cryptic plant,Asclepias meadii: applications of mark‐recapture models to long‐term monitoring studies
Authors: Alexander Helen M. , Slade Norman A. , Kettle W. Dean , Pittman Galen L. , Reed Aaron W. 
Published: January 2009

SummaryAnalysis of population trajectories is central to assessing risk in populations of conservation concern. In animal studies, researchers realize that probabilities of detection of individuals are often less than one. Plants can also escape detection due to dormancy, herbivory, or observer error, but such information is rarely incorporated into population studies.We monitored a population ofAsclepias meadii, a rare long‐lived prairie perennial. Despite standardized methods, numbers of observed plants fluctuated greatly from 1992 to 2006. Individual plants often had periods of 1–5 years between initial and final sighting when no stems were found. To determine the actual population trajectories, we estimated rates of survival and population growth using mark‐recapture models. We also estimated initial and resighting probabilities of detection. In 2007, we repeated surveys to identify reasons for low detection probabilities.We estimated 95% annual survival and a population growth rate of 1.023. Probabilities of initial detection were low (typically from 0.120 to 0.311 depending on prairie burn treatment), whereas average probability of detection for marked plants was 0.728.Comparisons of survival estimates from 15‐ and 8‐year data sets revealed that survival estimates decline in the final years of a multi‐year period, probably due to heterogeneity in encounter histories.By conducting three different surveys in 2007, we found that both herbivory over a multiple‐week period and observer error contributed substantially to gaps in detection.Synthesis.Probabilities of detection that are less than one complicate interpretation of population dynamics, whether of mobile animals or inconspicuous plants. Our work illustrates three general points that could apply to many plant population studies: (i) mark‐recapture models may provide insights on vital rates and population trajectories despite the extreme variability in count data that can arise because of low detectability, (ii) probabilities of initial detection can be quantified and can be considerably less than probabilities of resighting, and (iii) repeated surveys can help researchers determine the degree to which dormancy, herbivory, or observer error contribute to low probabilities of detection. Consideration of these points can improve the design and analysis of monitoring programs.
Introduction history and species characteristics partly explain naturalization success of North American woody species in Europe
Authors: Bucharova Anna , Van Kleunen Mark 
Published: January 2009

Summary

The search for general characteristics of invasive species has not been very successful yet. A reason for this could be that current invasion patterns are mainly reflecting the introduction history (i.e. time since introduction and propagule pressure) of the species. Accurate data on the introduction history are, however, rare, particularly for introduced alien species that have not established. As a consequence, few studies that tested for the effects of species characteristics on invasiveness corrected for introduction history.
We tested whether the naturalization success of 582 North American woody species in Europe, measured as the proportion of European geographic regions in which each species is established, can be explained by their introduction history. For 278 of these species we had data on characteristics related to growth form, life cycle, growth, fecundity and environmental tolerance. We tested whether naturalization success can be further explained by these characteristics. In addition, we tested whether the effects of species characteristics differ between growth forms.
Both planting frequency in European gardens and time since introduction significantly increased naturalization success, but the effect of the latter was relatively weak. After correction for introduction history and taxonomy, six of the 26 species characteristics had significant effects on naturalization success. Leaf retention and precipitation tolerance increased naturalization success. Tree species were only 56% as likely to naturalize as non‐tree species (vines, shrubs and subshrubs), and the effect of planting frequency on naturalization success was much stronger for non‐trees than for trees. On the other hand, the naturalization success of trees, but not for non‐trees, increased with native range size, maximum plant height and seed spread rate.
Synthesis. Our results suggest that introduction history, particularly planting frequency, is an important determinant of current naturalization success of North American woody species (particularly of non‐trees) in Europe. Therefore, studies comparing naturalization success among species should correct for introduction history. Species characteristics are also significant determinants of naturalization success, but their effects may differ between growth forms.
Tufa as a record of perennial fresh water in a semi‐arid rift basin, Kapthurin Formation, Kenya
Authors: JOHNSON CARA ROURE , ASHLEY GAIL M. , DE WET CAROL B. , DVORETSKY RACHEL , PARK LISA , HOVER VICTORIA C. , Bernhart Owen R. , MCBREARTY SALLY 
Published: January 2009

AbstractLithological and biological features of a fossiliferous tufa in the Kapthurin Formation, Baringo, Kenya, reveal the presence of a lush wetland in a semi‐arid environment during the Middle Pleistocene (ca 500 ka) in this portion of the East African Rift Valley. Four geological sections, each between 3 m and 8 m in thickness, exposed over a distance of 0·5 km, reveal a 1 to 2 m thick paludal tufa which is composed of three carbonate beds, two dark grey silty claystones and a reddish‐brown silty palaeosol. High resolution stratigraphic analysis, carbonate petrography, stable isotope and elemental geochemistry, clay mineralogy and fossil remains (molluscs, ostracods, diatoms and charophytes) reveal a ground water‐fed system that fluctuated in depth and periodically disappeared altogether. Oxygen isotope ratios (δ18O) of tufa matrix range from −4·5‰ to −8·0‰ (Vienna Pee Dee Belemnite) and become more positive up section, indicating the decreasing influence of fault‐related fluids and increasing residence time or freshness of wetland water, rather than evaporative enrichment. This spring was situated on a lake margin during low lake levels, thrived during periods of increased ground water input and was ultimately replaced by an alkaline lake. The wetland would appear to have existed during a cool interval within the generally warm Marine Isotope Stage 13 or perhaps during the warm second half of Marine Isotope Stage 13. The ground water source of this wetland arose through a fault system. Thus, the position of the tufa deposit is controlled structurally but the timing and duration of the wetland system may have been influenced by both climatic and tectonic factors.
Nest‐to‐nest dispersal of Chaetodactylus krombeini (Acari, Chaetodactylidae) associated with Osmia cornifrons (Hym., Megachilidae)
Authors: Park Y.‐L. , Kondo V. , White J. , West T. , McConnell B. , McCutcheon T. 
Published: January 2009

AbstractA cleptoparasitic mite, the Krombein’s hairy‐footed mite, Chaetodactylus krombeini Baker (Acari, Chaetodactylidae) became a key pest that affects the maintenance and propagation of Osmia spp. (Hym., Megachilidae), thus disrupting orchard pollination in the United States. Although hypopi, the dispersal stages of C. krombeini, are known to disperse from nest to nest by hitchhiking on Osmia cornifrons adults, we observed that they might disperse in other ways too in commercial orchards. This study was conducted to elucidate the nest‐to‐nest dispersal mechanisms of C. krombeini hypopi. We tested three potential dispersal mechanisms of C. krombeini other than phoresy by O. cornifrons: (1) dispersal by walking from nest to entrances of nearby nests, (2) dispersal by walking from nest to nest through emergence holes made by parasitic wasps on nests, and (3) dispersal by being unloaded and uptaken to and from flowers by O. cornifrons. Results of this study showed that C. krombeini hypopi could disperse from a nest to nearby nests by walking through nest entrances and holes made by parasitic wasps of O. cornifrons. Although 0.06% of C. krombeini hypopi on blueberry flowers were picked up by O. cornifrons, they were not able to be unloaded to flowers from O. cornifrons and no hypopi could inhabit or survive on blueberry flowers. This indicated no or very low chance of C. krombeini hypopi dispersal via blueberry flowers. Based on our findings of C. krombeini dispersal ecology, development of C. krombeini control strategies are discussed in this article.
Assessing the influence of inflorescence traits on the susceptibility of grape to vine moths
Authors: Pavan F. , Stefanelli G. , Cargnus E. , Villani A. 
Published: January 2009

AbstractIn north‐eastern Italy during 1994–2006, studies were carried out on the susceptibility of grapevine cultivars to the first generations of the European vine moth [Lobesia botrana (Den. and Shiff.); Lep., Tortricidae] and the European grape berry moth [Eupoecilia ambiguella (Hb.); Lep., Cochylidae]. In five different years, the larval population density of both moth species and the larval age composition of L. botrana were recorded on 11 grapevine cultivars (Cabernet Sauvignon, Carmenère, Chardonnay, Pinot Gris, Merlot, Refosco dal Peduncolo Rosso, Rhine Riesling, Sauvignon Blanc, Terrano, Tocai Friulano, Verduzzo Friulano), grown in the same vineyard. The influence of inflorescence traits on these demographic parameters was also evaluated. On a 5‐year average, L. botrana significantly prevailed over E. ambiguella in nine of the 11 cultivars. Chardonnay and Pinot Gris were the most infested cultivars. Age composition of L. botrana larvae varied with cultivar type, being older on Chardonnay and Tocai Friulano than the other cultivars. Inflorescence earliness and hairiness explained the majority of the variability in cultivar susceptibility. In particular, the larval population level of the two vine moths was positively correlated with inflorescence earliness and negatively correlated with inflorescence hairiness. Lobesia botrana larval age composition was negatively correlated with inflorescence hairiness. Inflorescence earliness and hairiness could be used to predict in each grape‐growing area which cultivars are potentially more infested in the first generation. Inflorescences without pubescence, favouring an older age composition of first generation larvae, could induce an earlier second generation.
Mortality factors affecting Bemisia tabaci populations on cotton in Turkey
Authors: Karut K. , Naranjo S. E. 
Published: January 2009

AbstractCohort‐based, partial life tables were constructed to determine the sources and rates of mortality factors affecting Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) on cotton in the eastern Mediterranean region of Turkey over a two year period. Mortality factors were recorded as due to predation, parasitism, dislodgement and unknown for five developmental stages. Across 10 independent cohorts, the highest median rate of marginal mortality pooled over all stages was attributed to parasitism (0.69) followed by predation (0.67). The key factor was hypothesized to be parasitism based on graphical and regression‐based comparison of individual factor k‐values to total generational mortality. The greatest amount of marginal immature mortality occurred during the fourth nymphal stadium (median = 0.77) and mortality during this stage was also most predictive of variation in total mortality. Pooled over all developmental stages, the highest rates of irreplaceable mortality were associated with parasitism (median: 0.112), followed by predation (0.088), dislodgement (0.020) and unknown (0.017). Although crawler mortality was not explicitly measured, sensitivity analyses indicated that mortality during this stage would have changed total mortality by only 0.45–1.21% and had no effect on identification of key factors. There was no significant effect of cotton cultivar on any mortality factor or total mortality over the two years of study. Results suggest that conservation of natural enemies, particularly parasitoids, may provide for more sustainable management of B. tabaci on cotton in Turkey.
Distribution and molecular characterization of distinct Asian populations of Bemisia tabaci (Hemiptera: Aleyrodidae) in Japan
Authors: Ueda S. , Kitamura T. , Kijima K. , Honda K.‐I. , Kanmiya K. 
Published: January 2009

Abstract Bemisia tabaci (Gennadius) is considered to be the most economically important pest insect worldwide. The invasive variant, the Q biotype of B. tabaci was first identified in 2004, and has caused significant crop yield losses in Japan. The distribution and molecular characterization of the different biotypes of B. tabaci in Japan have been little investigated. In this study, B. tabaci populations were sampled from the Japanese Archipelago, the Amami Archipelago and the Ryukyu Islands between 2004 and 2008, and the nucleotide sequences of their mitochondrial cytochrome oxidase I genes were determined. Bayesian phylogenetic relationship analysis provided the first molecular evidence that the indigenous Japanese populations could be separated into four distinct genetic groups. One major native population from the Japanese Archipelago, given the genetic group name Lonicera japonica, was separated into an independent group, distinct from the other genetic groups. The second major population, the Nauru biotype in the Asia II genetic group, was identified in the Amami Archipelago and the Ryukyu Islands. Two distinct minor genetic groups, the Asia I and the China, were also identified. One invasive B‐related population belonging to the Mediterranean/Asia Minor/Africa genetic group has been identified in Honshu. All lineages generated by the phylogenetic analyses were supported by high posterior probabilities. These distinct indigenous B. tabaci populations developed in Japan under geographical and/or biological isolation, prior to recent invasions of the B and Q biotypes.
Predicting insect pest status under climate change scenarios: combining experimental data and population dynamics modelling
Authors: Estay S. A. , Lima M. , Labra F. A. 
Published: January 2009

AbstractClimate change could profoundly affect the status of agricultural insect pests. Several approaches have been used to predict how the temperature and precipitation changes could modify the abundances, distributions or status of insect pests. In this article it is demonstrated how the use of simple models, such as Ricker’s classic equation, including a mechanistic representation of the influence of exogenous forces may improve our predictive capacity of the dynamic behaviour of insect populations. Using data from classical experiments in population ecology, we evaluate how temperature and humidity influence the density of two stored grain insect pest, Tribolium confusum and Callosobruchus chinensis, and then, using the A2 and B2 scenarios proposed by the Intergovernmental Panel on Climate Change and the previous modelling, we develop predictions over the future pest status of T. confusum along South America austral region, and specifically for eight cities in the continental Chilean territory. Tribolium confusum and C. chinensis show qualitatively different responses to the exogenous forcing of temperature and humidity, respectively. Our simulations predict a change in the equilibrium density of T. confusum from 10 to 14% under the moderate B2 scenario and 12 to 22% under the extreme A2 scenario to the period, 2071–2100. Both results imply a severe change in the pest status of this species in the southern region. This study illustrates how the use of theoretically based models may improve our predictive capacity. This approach provides an opportunity to examine the link between invasive species and climate change and how new suitable habitat may become available for species whose niche space is limited in some degree by climatic conditions. The use of different scenarios allows us to examine the sensitivity of the predictions, and to improve the communication with the general public and decision‐makers; a key aspect in integrated pest management.
The use of taxonomic distinctness indices in assessing patterns of biodiversity in modular organisms
Authors: Bevilacqua Stanislao , Fraschetti Simonetta , Terlizzi Antonio , Boero Ferdinando 
Published: January 2009

AbstractEstimating diversity of modular organisms may be problematic due to actual difficulties in discriminating between ‘individuals’ and quantifying their abundances. Quantitative data, when available, are collected through methods that could preclude the application of classical diversity indices, making comparisons among studies difficult. Taxonomic distinctness indices, such as the ‘Average Taxonomic Distinctness’ (Δ+) and the ‘Variation in Taxonomic Distinctness’ (Λ+) may represent suitable tools in investigating diversity beyond the simple species number. The potential usefulness of such indices has been explored almost exclusively on unitary organisms, neglecting modular ones. In this study, we employed Δ+ and Λ+ to analyse patterns of diversity of epiphytic hydroid assemblages living on Cystoseira seaweeds at a hierarchy of spatial scales, along 800 km of rocky coast (SE Italy). ANOVA on species richness and Λ+ showed no significant difference in sample diversity at the investigated spatial scales. In contrast, there were significant differences at the scale of 10s of km in Δ+. Analyses based on simulations detected significant variations at all spatial scales in Δ+. Such findings underline the potential of Δ+ in highlighting relevant spatial scales of variation in patterns of hydroid diversity. Our results also suggest that the interplay between natural environmental variations and the complex ecological traits of modular organisms might affect taxonomic distinctness indices. We stress the need for further investigations focusing on modular organisms before any generalizations on the use of taxonomic relatedness measures in examining marine biodiversity can be made.
Trends of ulcerative colitis‐associated colorectal cancer in Korea: A KASID study
Authors: Kim Beom Jin , Yang Suk Kyun , Kim Joo Sung , Jeen Yoon Tae , Choi Hwang , Han Dong Su , Kim Hyo Jong , Kim Won Ho , Kim Jae Yong , Chang Dong Kyung 
Published: January 2009

AbstractBackground and Aim:  The number of patients with ulcerative colitis (UC) in Korea has increased. In addition, the number of patients with colorectal cancer (CRC) associated with UC has also increased. Therefore, this population‐based nationwide study was conducted to investigate the incidence of CRC in patients with UC in Korea and compare these results to those of studies conducted in other countries.Methods:  The Korean Association for the Study of Intestinal Diseases (KASID) reviewed 7061 cases of UC that occurred between 1970 and 2005 and found a total of 26 cases of CRC.Results:  The overall prevalence of CRC in patients with UC was 0.37%. In addition, the estimated cumulative risk of UC‐associated CRCs was 0.7% for patients that had UC for 10 years, 7.9% for patients that had UC for 20 years, and 33.2% for patients that had UC for 30 years. The mean age at the time of diagnosis with CRC was 49.6 years, and the mean duration of UC prior to the development of CRC was 11.5 years. Most UC‐associated CRCs were diagnosed after they were already in advanced stages; however, the stage at diagnosis was lower in patients that had good compliance with medical treatment.Conclusion:  The cumulative incidence of UC‐associated CRCs in Korea was found to be comparable to that of western countries. The overall occurrence of UC‐associated CRC in Korea may be growing, therefore, intensive surveillance colonoscopy and constructive chemoprevention should be encouraged to enable early detection and treatment of UC‐associated CRCs in Korea.
The clinical utility of biomarkers and the nonalcoholic steatohepatitis CRN liver biopsy scoring system in patients with nonalcoholic fatty liver disease
Authors: Malik Raza , Chang Michael , Bhaskar Killimangalam , Nasser Imad , Curry Michael , Schuppan Detlef , Byrnes Valerie , Afdhal Nezam 
Published: January 2009

AbstractBackground and Aims:  We identified patients with nonalcoholic fatty liver disease (NAFLD) to determine the predictive value of serum markers to diagnose histological steatohepatitis (NASH).Methods:  Demographic, serological, radiological and histological variables on 95 consecutive patients with NAFLD were recorded. The serum markers studied were CK18, Hyaluronic acid, TIMP 1 and YKL 40. The NAS score and the metavir score were the histological scoring systems used.Results:  CK18 levels were higher in the NASH group compared to the simple steatosis group (394 ± 53 µ/L vs 194 ± 26 µ/L; P < 0.05). In assessing clinical effectiveness, CK18 yielded an AUC of 0.8 for NASH (cut‐off value 300 µ/L gives PPV 81% and NPV 85%).The fibrosis markers showed no differences between groups. We stratified the same cohort according to liver fibrosis (F0 vs F1–F4). Fibrosis was associated with advanced age, high body mass index and type 2 diabetes. The biomarkers performed relatively poorly at identifying liver fibrosis (F1–F4), with HA performing the best (AUC 0.73); performance improved for advanced fibrosis (F3/F4) ‐ (HA: AUC 0.77). The NAS score performed the best overall at identifying liver fibrosis (AUC 0.79).Discussion:  CK18 is the only biomarker studied that can identify NASH. Additionally, liver biopsy should be performed in all high risk patients to determine the standardised NAS score to identify patients at high risk of disease progression.