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Long-term Data (long-term + data)

Distribution by Scientific Domains
Life Sciences59%
Medical Sciences28%
Engineering6%
Earth and Environmental Science6%
Distribution within Life Sciences
Ecology & Organismal Biology25%
Conservation Science20%

Terms modified by Long-term Data

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    Selected Abstracts

    Song similarity predicts hybridization in flycatchers

    JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2006
    A. QVARNSTRÖM
    Abstract Given that population divergence in sexual signals is an important prerequisite for reproductive isolation, a key prediction is that cases of signal convergence should lead to hybridization. However, empirical studies that quantitatively demonstrate links between phenotypic characters of individuals and their likelihood to hybridize are rare. Here we show that song convergence between sympatric pied (Ficedula hypoleuca) and collared flycatchers (F. albicollis) influence social and sexual interactions between the two species. In sympatry, the majority of male pied flycatchers (65%) include various parts of collared flycatcher song in their song repertoire (but not vice versa). Playback experiments on male interactions demonstrate that male collared flycatchers respond similarly to this ,mixed' song as to conspecific song. Long-term data on pairing patterns show that males singing a converged song attract females of the other species: female collared flycatchers only pair with male pied flycatchers if the males sing the mixed song type. From the perspective of a male pied flycatcher, singing a mixed song type is associated with 30% likelihood of hybridization. This result, combined with our estimates of the frequency of mixed singers, accurately predicts the observed occurrence of hybridization among male pied flycatchers in our study populations (20.45% of 484 pairs; predicted 19.5%). Our results support the suggestion that song functions as the most important prezygotic isolation mechanism in many birds. [source]

    Dynamic social system in Nubian ibex: can a second mating season develop in response to arid climate?

    JOURNAL OF ZOOLOGY, Issue 3 2008
    A. Massolo
    Abstract We studied a population of Nubian ibex Capra ibex nubiana in the eastern extreme of its range, the hyper-arid central desert of the Sultanate of Oman. Long-term data were collected from January 1983 to December 1997 by direct observation, as well as VHF telemetry on 12 animals (eight from 1987 to 1990; four from 1994 to 1996). We recorded 884 sightings: 40.4% of single animals and 59.6% of groups. Although no significant monthly variation of group size (Jarman's Typical Group Size) was found, there were distinct peaks in March (4.0 ind. group,1) and September (5.1 ind. group,1). Groups of males and females formed especially in March and November, and female,kid groups in February and July,August. Our data may suggest two mating periods: the first one in autumn (similar to the rut of ibex in temperate mountain areas), with kids born in spring/early summer, after winter,spring rainfall, and the second one in spring, with kids born in late summer/autumn, before winter,spring rainfalls. We suggest that the second rutting period may have evolved as a micro-evolutionary process, with the local population adapting to hyper-arid environment constraints. The spring mating season may favour only females in prime conditions, who can afford a pregnancy in the local severe summers and will deliver kids when plant greening begins, in the autumn, whereas the autumn (original) mating season may be afforded by any female, but kids will be born in an unfavourable period, before the summer drought. [source]

    Long-term data on the survival of patients with prostate cancer treated with radical prostatectomy in the prostate-specific antigen era

    BJU INTERNATIONAL, Issue 1 2010
    Hendrik Isbarn
    Study Type , Therapy (case series) Level of Evidence 4 OBJECTIVE To examine the long-term rates of biochemical recurrence (BCR)-free survival, cancer-specific mortality (CSM)-free survival, and overall survival (OS) in patients with prostate cancer treated with open radical prostatectomy (RP) in the prostate-specific antigen (PSA) era. PATIENTS AND METHODS The study comprised 436 patients who were treated with RP between 1992 and 1997 at our institution. None received adjuvant/salvage therapy in the absence of BCR. The BCR-free, CSM-free and OS rates were defined using the Kaplan-Meier method. Multivariable Cox-regression models were used to test the effect of age, preoperative PSA level, neoadjuvant hormonal therapy, pT stage, lymph node status, RP Gleason sum and surgical margin status on BCR. RESULTS The median follow-up of censored patients was 122, 128, and 132 months for, respectively, BCR-free, CSM-free and OS estimates. The 10-year event-free survival rates for the same endpoints were 60%, 94% and 86%, respectively. Preoperative PSA level, RP Gleason sum, pT stage, lymph node status, and surgical margin status were independent predictors of BCR (all adjusted P < 0.05). CONCLUSIONS This study is the first to evaluate the long-term cancer control outcomes after RP from a European country in the PSA era. Our data indicate that RP provides excellent long-term survival rates in patients with clinically localized prostate cancer. Although ,40% of patients have BCR after 10 years of follow-up, the CSM rate after 10 years is as low as 6%. [source]

    Microbiological and clinical outcomes and patient satisfaction for two treatment options in the edentulous lower jaw after 10 years of function

    CLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2005
    Marc Quirynen
    Abstract Background: Long-term data on microbiological and clinical outcome as well as on patient satisfaction after implant therapy in the edentulous mandible are limited. Especially comparisons between fixed full prostheses (FFPs) and overdentures (ODs), or between anchoring systems for the latter are scarce. Aim: This study aimed to evaluate both of these parameters at the 10-year follow-up in a group of fully edentulous patients rehabilitated via an OD or a FFP (the latter to allow inter-group comparison). Material and methods: A total of 37 fully edentulous patients (25 ODs, 12 FFPs, age at implant installation ranged from 36 to 85 years) participated in this study. All subjects received their implants (Brånemark System®, Nobel Biocare AB, Gothenburg, Sweden) 10 years previously. For the ODs different attachment systems (bar, magnets, ball) had been applied that allowed a further intra-group comparison. At the follow-up visit, 10 years after the abutment insertion, a series of periodontal parameters were recorded, long-cone radiographs were taken and subgingival plaque samples were collected for analysis using checkerboard DNA,DNA hybridization. The clinical and radiographic data were recorded at abutment connection and after 1 and 10 years. Results: After 10 years of loading, mean plaque and bleeding indices and changes in attachment or marginal bone level were not significantly different, neither between the OD and FFP group, nor within the OD group. The marginal bone loss between abutment connection and year 10 was 0.86 and 0.73 mm for OD and FFP groups, respectively. The subgingival microbiota at implant sites from all (sub)-groups was comparable, with low numbers of DNA counts (±10 × 105) but high detection frequencies of Actinobacillus actinomycetemcomitans (>90%), Porphyromonas gingivalis (>85%) and Tannerella forsythensis (30%). The composition of the subgingival microbiota was influenced by probing depth and bleeding tendency. Patient satisfaction was very high for both types of prosthetic rehabilitation. The FFP group scored only slightly better for chewing comfort and general satisfaction. Conclusion: These data indicate that from the clinical and microbiological standpoint, as well as patient satisfaction, both an OD and a FFP offer a favourable long-term outcome. Résumé Les données à long terme de la guérison clinique et microbiologique ainsi que la satisfaction du patient après un traitement par implants dans la mandibule édentée sont limitées. Essentiellement des comparaisons entre les prothèses fixées complètes et les prothèses fixées amovibles ou entre les systèmes d'ancrage pour ces derniers sont rares. Cette étude a eu pour but d'évaluer ces paramètres après dix ans dans un groupe de patients complètement édentés qui avaient été soignés par une prothèse amovible ou fixée (cette dernière pour permettre la comparaison intergroupes). Trente-sept patients édentés [25 prothèses amovibles (OD), douze prothèses fixées (FFP), l'âge au moment du placement des implants était de 36 à 85 ans] ont participéà cette étude. Tous les sujets avaient reçu des implants Brånemark® 10 ans auparavant. Pour les prothèses amovibles, différents types d'attache (balle, aimant) avaient été utilisés, ce qui permettaient une comparaison intragroupe supplémentaire. Lors de la visite du suivi, dix ans après l'insertion des implants, une série de paramètres parodontaux ont été enregistrés, des radiographies par long cône prises et des échantillons de plaque sous-gingivale prélevés pour l'analyse utilisant l'hybridisation ADN-ADN échiquier. Les données cliniques et radiographiques ont été enregistrées au moment de la connexion de l'implant et après une et dix années. Dix années après la mise en charge, les indices de plaque et de saignement et les variations dans l'attache ou les niveaux osseux marginaux n'étaient pas significativement différents ni entre les groupes OD et FFP ni à l'intérieur du groupe OD. La perte osseuse marginale entre les connexions des piliers et dix ans après étaient respectivement de 0,86 et 0,73 mm pour les groupes OD et FFP. La flore sous-gingivale au niveau des implants pour tous les groupes et sous-groupes étaient semblables avec de faibles comptages ADN (±10 × 105) mais des fréquences de détection importantes de A. actinomycetemcomitans (>90%), P. gingivalis (>85%) et T.forsythensis (30%). La composition de la flore sous-gingivale a été influencée par la profondeur de la poche et la tendance au saignement. La satisfaction du patient était très élevée pour les deux types de prothèses. Le groupe FFP n'était qu'un petit peu meilleur pour le confort à la mastication et la satisfaction générale. Ces données indiquent que d'un point de vue clinique et microbiologique autant que d'un point de vue de satisfaction du patient les prothèses amovibles et fixées sont favorables à long terme. Zusammenfassung Hintergrund: Die Langzeitresultate über den mikrobiologischen und klinischen Verlauf und über die Zufriedenheit der Patienten nach Implantatversorgung im zahnlosen Unterkiefer sind limitiert. Im Speziellen sind Vergleiche zwischen festsitzenden totalen Brücken und Hybridprothesen und den verschiedenen Befestigungssystemen für Hybridprothesen selten. Ziel: Das Ziel der Studie war, beide Parameter anlässlich der Nachuntersuchung nach 10 Jahren bei einer Gruppe von zahnlosen Patienten, welche mit einer Hybridprothese oder mit einer festsitzenden Brücke wiederhergestellt worden waren, auszuwerten (bei den Hybridprothesen sollten auch Vergleiche innerhalb der Gruppe durchgeführt werden). Material und Methoden: Insgesamt nahmen 37 zahnlose Patienten an der Studie teil (25 Hybridprothesen (OD), 12 festsitzende Prothesen (FFP), Alter zum Zeitpunkt der Implantation 36 bis 85 Jahre). Alle Subjekte hatte vor 10 Jahren ihre Implantate erhalten (Brånemark System®, Nobel Biocare, Schweden). Bei den Hybridprothesen waren verschiedene Befestigungssysteme verwendet worden (Steg, Magnet, Kugeln). Dies erlaubte Vergleiche innerhalb der Gruppe. Bei der Nachuntersuchung 10 Jahre nach Einsetzten der Prothetikteile wurden parodontale Parameter aufgenommen, Röntgenbilder mit der Langkonustechnik angefertigt und subgingivale Plaqueproben zur Analyse mittels Ceckerboard DNA,DNA Hybridisierung entnommen. Die klinischen und radiologischen Daten wurden beim Einsetzten der Prothetikteile und nach 1 und 10 Jahren aufgenommen. Resultate: Nach 10 Jahren Belastung bestanden weder zwischen der OD und FFP Gruppe, noch innerhalb der OD Gruppe statistisch signifikante Unterschiede im mittleren Plaque- und Blutungsindex und in der Attachment- und marginalen Knochenhöhe. Der Verlust an marginalem Knochen zwischen der Montage der Prothetikteile und nach 10 Jahren betrug 0.86 mm für die OD Gruppe und 0.73 mm für die FFP Gruppe. Die subgingivale Flora war bei allen Implantatstellen der (Sub-) Gruppen vergleichbar. Es bestand eine geringe Anzahl an DNA Zählungen (±10 × 105) aber eine hohe Entdeckungsfrequenz für A. actinomycetemcomitans (>90%), P. gingivalis (>85%) und T. forsythensis (30%). Die Zusammensetzung der subgingivalen Mirkoflora wurde durch die Sondierungstiefe und die Blutungstendenz beeinflusst. Die Zufriedenheit der Patienten war für beide Arten der prothetischen Wiederherstellung sehr hoch. Die FFP Gruppe erreichte nur geringfügig bessere Werte bezüglich Kaukomfort und genereller Zufriedenheit. Schlussfolgerung: Diese Daten zeigen, dass sowohl vom klinischen und mikrobiologischen Standpunkt aus als auch seitens der Patientenzufriedenheit die Hybridprothese und die festsitzende totale Brücke gute Langzeitresultate zeigen. Resumen Antecedentes: Los datos a largo plazo sobre los resultados microbiológicos y clínicos al igual que la satisfacción del paciente tras la terapia de implantes en la mandíbula edéntula son limitados. Son especialmente escasas las comparaciones entre prótesis fija completa y sobredentaduras, o entre sistemas de anclaje. Intención: Este estudio se intentó para evaluar ambos parámetros en el control de seguimiento de los 10 años en un grupo de pacientes totalmente edéntulos rehabilitados por medio de una sobredentadura o una prótesis completa fija (la última para permitir comparaciones intergrupo). Material y métodos: Un total de 37 pacientes totalmente edéntulos (25 sobredentaduras (OD), 12 prótesis completas fijas (FFP), la edad en el momento de la implantación varió entre 36 a 85 años) participaron en este estudio. Todos los sujetos recibieron sus implantes (Brånemark System®, Nobel Biocare, Suecia) 10 años antes. Para las sobredentaduras se aplicaron diferentes sistemas de anclaje (barras, imanes, bolas) lo que permitieron una ulterior comparación intragrupo. En la visita de seguimiento, 10 años tras la colocación de los pilares, se recogieron una serie de parámetros periodontales, se tomaron radiografías de cono largo y se recogieron muestras de la placa subgingival para análisis usando la cuadrícula de DNA-DNA hibridación. Los datos clínicos y radiográficos se recogieron al conectar los pilares y tras 1 y 10 años. Resultados: Tras 10 años de carga, los índices medios de placa y sangrado y los cambios en el nivel óseo marginal y de inserción no fueron significativos, ni entre los grupos OD y FFP, ni dentro del grupo OD. La pérdida de hueso marginal entre la conexión de los pilares y el año 10 fue de 0.86 y 0.73 mm para los grupos OD y FFP, respectivamente. La microflora subgingival en los lugares de implantes fue comparable entre todos los (sub)-grupos, con un bajo recuento de DNA (±10 × 105) pero una alta detección de A. actinomycetemcomitans (>90%), P. gingivalis (>85%) y T. forsythensis (30%). La composición de la microflora subgingival fue influida por la profundidad de sondaje y la tendencia al sangrado. La satisfacción de los pacientes fue muy alta para ambos grupos de rehabilitación protésica. El grupo FFP puntuó solo un poco mejor para la satisfacción masticatoria y satisfacción general. Conclusión: Estos datos indican que desde el punto de vista clínico y microbiológico al igual que la satisfacción del paciente, tanto la sobredentadura como la prótesis completa fija ofrecen unos resultados favorables a largo plazo. [source]

    An Ecological and Economic Assessment of the Nontimber Forest Product Gaharu Wood in Gunung Palung National Park, West Kalimantan, Indonesia

    CONSERVATION BIOLOGY, Issue 6 2001
    Gary D. Paoli
    We studied the demographic effect and economic returns of harvesting aromatic gaharu wood from fungus-infected trees of Aquilaria malaccensis Lam. at Gunung Palung National Park, Indonesia, to evaluate the management potential of gaharu wood. Aquilaria malaccensis trees openface> 20 cm in diameter occurred at low preharvest densities (0.16,0.32 ha) but were distributed across five of six forest types surveyed. During a recent harvest, 75% of trees were felled, with harvest intensities ranging from 50% to 100% among forest types. Overall, 50% of trees contained gaharu wood, but trees at higher elevations contained gaharu wood more frequently ( 73%) than trees at lower elevation (27%). The mean density of regeneration ( juveniles> 15 cm in height) near adult trees (3,7 m away) was 0.2/m2, 200 times greater than at random in the forest (10/ha), but long-term data on growth and survivorship are needed to determine whether regeneration is sufficient for population recovery. Gaharu wood extraction from Gunung Palung was very profitable for collectors, generating an estimated gross financial return per day of US $8.80, triple the mean village wage. Yet, the estimated sustainable harvest of gaharu wood at natural tree densities generates a mean net present value of only $10.83/ha, much lower than that of commercial timber harvesting, the dominant forest use in Kalimantan. Returns per unit area could be improved substantially, however, by implementing known silvicultural methods to increase tree densities, increase the proportion of trees that produce gaharu wood, and shorten the time interval between successive harvests. The economic potential of gaharu wood is unusual among nontimber forest products and justifies experimental trials to develop small-scale cultivation methods. Resumen: Datos ecológicos y económicos son esenciales para la identificación de productos forestales no maderables tropicales con potencial para la extracción sostenible y rentable en un sistema bajo manejo. Estudiamos el efecto demográfico y los beneficios económicos de la cosecha de la madera aromática gaharu de árboles de Aquilaria malaccenis Lam infectados por hongos en el Parque Nacional Gunung Palung Indonesia para evaluar el potencial de manejo de la madera. Arboles de Aquilaria malaccenis> 20 cm de diámetro ocurrieron en bajas densidades precosecha (0.16,0.32 ha,1) pero se distribuyeron en cinco de los seis tipos de bosque muestreados. Durante una cosecha reciente, 75% de los árboles fueron cortados, con intensidades de cosecha entre 50 y 100% en los tipos de bosque. En conjunto, 50% de los árboles contenían madera gaharu, pero árboles de elevaciones mayores contenían madera gaharu más frecuentemente ( 73%) que árboles de elevaciones menores (27%). La densidad promedio de regeneración ( juveniles> 15 cm de altura) cerca de árboles adultos (de 3 a 7 m de distancia) fue de 0.2 m,2, 200 veces mayor que en el bosque (10 ha,1), pero se requieren datos a largo plazo sobre el crecimiento y la supervivencia para determinar si la regeneración es suficiente para la recuperación de la población. La extracción de madera gaharu de Gunung Palung fue muy redituable, generando un rendimiento financiero bruto estimado en US $8.80 diarios, el triple del salario promedio en la zona. Sin embargo, la cosecha sostenible estimada de madera gaharu en densidades naturales de árboles genera un valor presente neto de sólo $10.83 ha,1, mucho menor que el de la cosecha comercial de madera, uso dominante del bosque en Kalimantan. Sin embargo, los rendimientos por unidad de área podrían mejorar sustancialmente mediante la instrumentación de métodos silviculturales para incrementar la densidad de árboles, incrementar la proporción de árboles que producen madera gaharu y reducir el intervalo de tiempo entre cosechas sucesivas. El potencial económico de la madera gaharu es poco usual entre los productos forestales no maderables y justifica la experimentación para desarrollar métodos de cultivo en pequeña escala. [source]

    Managing childhood obesity: when lifestyle change is not enough

    DIABETES OBESITY & METABOLISM, Issue 11 2010
    C. Hearnshaw
    The management of childhood obesity is a clinical dilemma. Paediatricians will see those children whose weight is at the severe end of the spectrum with obesity-related co-morbidities and for whom more intensive weight loss therapies may be appropriate. A literature review was performed (January 1995,January 2010) of the roles of pharmacotherapy or bariatric surgery in the management of childhood obesity. Three hundred and eighty-three abstracts were reviewed and 76 full-text articles were requested. Of these, 34 were excluded and a total of 21 pharmacotherapy papers and 22 papers on surgery were reviewed in detail. All studies involved adolescents. Pharmacotherapy: Most studies were small and of short duration, the notable exceptions being two large RCTs of sibutramine and orlistat. Sibutramine led to a mean estimated change in BMI from baseline of ,3.1 kg/m2 vs. ,0.3 kg/m2 for placebo over 12 months. Orlistat was also beneficial with a mean reduction in BMI of 0.55 vs. an increase of 0.31 kg/m2 in the placebo group at 12 months. Bariatric surgery: Most papers presented clinical observations and there were no randomised controlled trials (RCTs). Robust selection criteria were not used and ideal candidate selection remains unclear. Most papers showed a significant benefit of surgery in severely obese adolescents in the short term but long-term data were sparse. There were a surprisingly large number of papers examining the benefits of intensive weight management in obese adolescents. The study design of many was inadequate and the role of pharmacotherapy or surgery in childhood obesity remains unclear. [source]

    Freshwater invasions: using historical data to analyse spread

    DIVERSITY AND DISTRIBUTIONS, Issue 1 2007
    Sarina E. Loo
    ABSTRACT Aquatic invasive species cause deleterious environmental and economic impacts, and are rapidly spreading through ecosystems worldwide. Despite this, very few data sets exist that describe both the presence and the absence of invaders over long time periods. We have used Geographical Information Systems (GIS) to analyse time-series data describing the spread of the freshwater invasive New Zealand mudsnail, Potamopyrgus antipodarum, in Victoria, Australia, over 110 years. We have mapped the snail's spread, estimated the percentage of stream length invaded through time, calculated the functional form of the spread rate, and investigated the role that the two proposed vectors , fish stocking and angling , have had in this invasion. Since it was first found in 1895, P. antipodarum has expanded its range in Victoria and now occurs throughout much of the southern and central areas of the state. The north of the state is relatively less invaded than the south, with the division corresponding approximately to the presence of the Great Dividing Range. We show that the snail's range has been increasing at an approximately exponential rate and estimate that 20% of total Victorian stream length is currently invaded. We also show that using long-term data can change the outcome of analyses of the relationship between vectors of spread and invasion status of separate catchments. When our time-series data were aggregated through time, the total numbers of fish stocking events and angling activity were both correlated with invasion. However, when the time-series data were used and the number of fish stocking events calculated up until the date of invasion, no relationships with stocking were found. These results underline the role that time-series data, based on both presences and absences, have to play when investigating the spread of invasive species. [source]

    When does parameter drift decrease the uncertainty in extinction risk estimates?

    ECOLOGY LETTERS, Issue 12 2003
    Stephen P. Ellner
    Abstract Halley (2003) proposed that parameter drift decreases the uncertainty in long-range extinction risk estimates, because drift mitigates the extreme sensitivity of estimated risk to estimated mean growth rate. However, parameter drift has a second, opposing effect: it increases the uncertainty in parameter estimates from a given data set. When both effects are taken into account, parameter drift can increase, sometimes substantially, the uncertainty in risk estimates. The net effect depends sensitively on the type of drift and on which model parameters must be estimated from observational data on the population at risk. In general, unless many parameters are estimated from independent data, parameter drift increases the uncertainty in extinction risk. These findings suggest that more mechanistic PVA models, using long-term data on key environmental variables and experiments to quantify their demographic impacts, offer the best prospects for escaping the high data requirements when extinction risk is estimated from observational data. [source]

    The power of time: spatiotemporal scaling of species diversity

    ECOLOGY LETTERS, Issue 8 2003
    Peter B. Adler
    Abstract The species,area relationship (SAR) provides the foundation for much of theoretical ecology and conservation practice. However, by ignoring time the SAR offers an incomplete model for biodiversity dynamics. We used long-term data from permanent plots in Kansas grasslands, USA, to show that the increase in the number of species found with increasing periods of observation takes the same power-law form as the SAR. A statistical model including time, area, and their interaction explains 98% of variation in mean species number and demonstrates that while the effect of time depends on area, and vice versa, time has strong effects on species number even at relatively broad spatial scales. Our results suggest equivalence of underlying processes in space and time and raise questions about the diversity estimates currently used by basic researchers and conservation practitioners. [source]

    Endovascular stent implantation for treatment of peripheral artery disease

    EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2007
    M. Schillinger
    Endovascular stent implantation is a rapidly emerging technology for treatment of arterial obstructions in the entire circulation. During recent years, several randomized studies evaluated the effects of stenting in lower limb arteries. We herein provide an overview on data of trials in the iliac and femoropopliteal vessel area discussing the benefits and limitations of endovascular stents. In the iliac arteries, midterm and long-term data from one randomized trial including analysis on patency, clinical outcomes, cost-effectiveness and quality of life indicate that balloon angioplasty with selective stenting remains the therapy of choice for endovascular revascularization. In the femoropopliteal arteries, balloon-expanding stents were not superior to balloon angioplasty for treatment of short lesions, and self-expanding nitinol stents also failed to show a beneficial effect in short lesions below 5 cm. However, including longer lesions, one randomized trial indicated a beneficial effect of nitinol stents in lesions with a median length around 10,12 cm. Further studies and longer follow-up intervals are needed to confirm these data. Meanwhile, balloon angioplasty with optional stenting also remains the recommended endovascular approach for the femoropopliteal segment. [source]

    A metapopulation perspective for salmon and other anadromous fish

    FISH AND FISHERIES, Issue 4 2007
    Nicolas Schtickzelle
    Abstract Salmonids are an important component of biodiversity, culture and economy in several regions, particularly the North Pacific Rim. Given this importance, they have been intensively studied for about a century, and the pioneering scientists recognized the critical link between population structure and conservation. Spatial structure is indeed of prime importance for salmon conservation and management. At first glance, the essence of the metapopulation concept, i.e. a population of populations, widely used on other organisms like butterflies, seems to be particularly relevant to salmon, and more generally to anadromous fish. Nevertheless, the concept is rarely used, and barely tested. Here, we present a metapopulation perspective for anadromous fish, assessing in terms of processes rather than of patterns the set of necessary conditions for metapopulation dynamics to exist. Salmon, and particularly sockeye salmon in Alaska, are used as an illustrative case study. A review of life history traits indicates that the three basic conditions are likely to be fulfilled by anadromous salmon: (i) the spawning habitat is discrete and populations are spatially separated by unsuitable habitat; (ii) some asynchrony is present in the dynamics of more or less distant populations and (iii) dispersal links populations because some salmon stray from their natal population. The implications of some peculiarities of salmon life history traits, unusual in classical metapopulations, are also discussed. Deeper understanding of the population structure of anadromous fish will be advanced by future studies on specific topics: (i) criteria must be defined for the delineation of suitable habitats that are based on features of the biotope and not on the presence of fish; (ii) the collection of long-term data and the development of improved methods to determine age structure are essential for correctly estimating levels of asynchrony between populations and (iii) several key aspects of dispersal are still poorly understood and need to be examined in detail: the spatial and temporal scales of dispersal movements, the origin and destination populations instead of simple straying rates, and the relative reproductive success of immigrants and residents. [source]

    Lake responses to reduced nutrient loading , an analysis of contemporary long-term data from 35 case studies

    FRESHWATER BIOLOGY, Issue 10 2005
    ERIK JEPPESEN
    Summary 1. This synthesis examines 35 long-term (5,35 years, mean: 16 years) lake re-oligotrophication studies. It covers lakes ranging from shallow (mean depth <5 m and/or polymictic) to deep (mean depth up to 177 m), oligotrophic to hypertrophic (summer mean total phosphorus concentration from 7.5 to 3500 ,g L,1 before loading reduction), subtropical to temperate (latitude: 28,65°), and lowland to upland (altitude: 0,481 m). Shallow north-temperate lakes were most abundant. 2. Reduction of external total phosphorus (TP) loading resulted in lower in-lake TP concentration, lower chlorophyll a (chl a) concentration and higher Secchi depth in most lakes. Internal loading delayed the recovery, but in most lakes a new equilibrium for TP was reached after 10,15 years, which was only marginally influenced by the hydraulic retention time of the lakes. With decreasing TP concentration, the concentration of soluble reactive phosphorus (SRP) also declined substantially. 3. Decreases (if any) in total nitrogen (TN) loading were lower than for TP in most lakes. As a result, the TN : TP ratio in lake water increased in 80% of the lakes. In lakes where the TN loading was reduced, the annual mean in-lake TN concentration responded rapidly. Concentrations largely followed predictions derived from an empirical model developed earlier for Danish lakes, which includes external TN loading, hydraulic retention time and mean depth as explanatory variables. 4. Phytoplankton clearly responded to reduced nutrient loading, mainly reflecting declining TP concentrations. Declines in phytoplankton biomass were accompanied by shifts in community structure. In deep lakes, chrysophytes and dinophytes assumed greater importance at the expense of cyanobacteria. Diatoms, cryptophytes and chrysophytes became more dominant in shallow lakes, while no significant change was seen for cyanobacteria. 5. The observed declines in phytoplankton biomass and chl a may have been further augmented by enhanced zooplankton grazing, as indicated by increases in the zooplankton : phytoplankton biomass ratio and declines in the chl a : TP ratio at a summer mean TP concentration of <100,150 ,g L,1. This effect was strongest in shallow lakes. This implies potentially higher rates of zooplankton grazing and may be ascribed to the observed large changes in fish community structure and biomass with decreasing TP contribution. In 82% of the lakes for which data on fish are available, fish biomass declined with TP. The percentage of piscivores increased in 80% of those lakes and often a shift occurred towards dominance by fish species characteristic of less eutrophic waters. 6. Data on macrophytes were available only for a small subsample of lakes. In several of those lakes, abundance, coverage, plant volume inhabited or depth distribution of submerged macrophytes increased during oligotrophication, but in others no changes were observed despite greater water clarity. 7. Recovery of lakes after nutrient loading reduction may be confounded by concomitant environmental changes such as global warming. However, effects of global change are likely to run counter to reductions in nutrient loading rather than reinforcing re-oligotrophication. [source]

    Relative influence of fisheries and climate on the demography of four albatross species

    GLOBAL CHANGE BIOLOGY, Issue 7 2010
    VIRGINIE ROLLAND
    Abstract Worldwide ecosystems are modified by human activities and climate change. To be able to predict future changes, it is necessary to understand their respective role on population dynamics. Among the most threatened species are top predators because of their position in the food web. Albatross populations are potentially affected by both human activities, especially longline fisheries, and climatic fluctuations. Based on long-term data (1985,2006), we conducted through a comparative approach a demographic analysis (adult survival and breeding success) on four albatross species breeding on the Indian Ocean sub-Antarctic Islands to assess the relative impact of climate and fisheries during and outside the breeding season. The study revealed that adult survival of almost all species was not affected by climate, and therefore probably canalized against climatic variations, but was negatively affected by tuna longlining effort in three species. Breeding success was affected by climate, with contrasted effects between species, with Southern Oscillation Index having an impact on all species but one. Differences in demographic responses depended on the foraging zone and season. In order to predict population trajectories of seabirds such as albatrosses, our results show the importance of assessing the relative influence of fishing and climate impacts on demography. [source]

    Detecting the impact of oceano-climatic changes on marine ecosystems using a multivariate index: The case of the Bay of Biscay (North Atlantic-European Ocean)

    GLOBAL CHANGE BIOLOGY, Issue 1 2008
    GEORGES HEMERY
    Abstract Large-scale univariate climate indices (such as NAO) are thought to outperform local weather variables in the explanation of trends in animal numbers but are not always suitable to describe regional scale patterns. We advocate the use of a Multivariate Oceanic and Climatic index (MOCI), derived from ,synthetic' and independent variables from a linear combination of the total initial variables objectively obtained from Principal Component Analysis. We test the efficacy of the index using long-term data from marine animal populations. The study area is the southern half of the Bay of Biscay (43°,47°N; western Europe). Between 1974 and 2000 we monitored cetaceans and seabirds along 131000 standardized line transects from ships. Fish abundance was derived from commercial fishery landings. We used 44 initial variables describing the oceanic and atmospheric conditions and characterizing the four annual seasons in the Bay of Biscay. The first principal component of our MOCI is called the South Biscay Climate (SBC) index. The winter NAO index was correlated to this SBC index. Inter-annual fluctuations for most seabird, cetacean and fish populations were significant. Boreal species (e.g. gadiformes fish species, European storm petrel and Razorbill ,) with affinities to cold temperate waters declined significantly over time while two (Puffin and Killer Whale) totally disappeared from the area during the study period. Meridional species with affinities to hotter waters increased in population size. Those medium-term demographic trends may reveal a regime shift for this part of the Atlantic Ocean. Most of the specific observed trends were highly correlated to the SBC index and not to the NAO. Between 40% and 60% of temporal variations in species abundance were explained by the multivariate SBC index suggesting that the whole marine ecosystem is strongly affected by a limited number of physical parameters revealed by the multivariate SBC index. Aside the statistical error of the field measurements, the remaining variation unexplained by the physical characteristics of the environment correspond to the impact of anthropogenic activities such overfishing and oil-spills. [source]

    Impact of climate change on runoff from a mid-latitude mountainous catchment in central Japan

    HYDROLOGICAL PROCESSES, Issue 10 2009
    Yoshinori Shinohara
    Abstract Hydrologic balance in high-altitude, mid-latitude mountain areas is important in terms of the water resources available to associated lowlands. This study examined how current and historical shifts in precipitation (P) patterns and concurrent increases in temperature (T) affected runoff (Q) and other hydrologic components in a mid-latitude mountain catchment of central Japan, using a combination of long-term data and a simplified hydrologic model, along with their stochastic treatment. The availability of intensive meteorological and hydrological data from the period 1997,2001 allowed the derivation of key relationships for the current climate that tie the forcing term to the parameters or state variables. By using the data recorded in the period 1965,2001, the force for driving the historical simulation was generated. Based on this model and historical shifts in P and T, the probability density functions of Q (pdf(Q)) was computed. A main novelty in this study is that such a stochastic representation, which is useful for considering the influence of projected shifts in environmental factors on the hydrologic budget, was provided. Despite the large increase in the rate of T in winter and spring, pdf(Q) in spring and summer varied appreciably during the time studied mainly because of an increase in snowmelt. An interannual change in whole-year Q was robust to shifts in T because while Q in spring increased, in summer it decreased, implying a crucial effect of global warming on mountain hydrologic regimes is change in the timing of Q. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Endovenous laser ablation for superficial venous insufficiency

    INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 1 2010
    R. Durai
    Summary Background:, Endovenous laser ablation (EVLA) is a new minimally invasive alternative to conventional surgery for superficial venous insufficiency and varicose veins, where laser energy is used to ablate the incompetent veins. Discussion:, Endovenous laser ablation avoids the need for surgical incisions, and the complications of surgical exploration of the groin or popliteal fossa, and stripping. The procedure is commonly performed under local anaesthesia, with immediate mobilisation and rapid return to normal activity. Severe varicosity of tributaries may require adjunctive procedures such as microphlebectomy or sclerotherapy. Conclusion:, Early outcomes and cosmesis are superior, and long-term data is accumulating that recurrence of EVLA rates may be lower. [source]

    Density dependence in a recovering osprey population: demographic and behavioural processes

    JOURNAL OF ANIMAL ECOLOGY, Issue 5 2008
    V. Bretagnolle
    Summary 1Understanding how density-dependent and independent processes influence demographic parameters, and hence regulate population size, is fundamental within population ecology. We investigated density dependence in growth rate and fecundity in a recovering population of a semicolonial raptor, the osprey Pandion haliaetus [Linnaeus, 1758], using 31 years of count and demographic data in Corsica. 2The study population increased from three pairs in 1974 to an average of 22 pairs in the late 1990s, with two distinct phases during the recovery (increase followed by stability) and contrasted trends in breeding parameters in each phase. 3We show density dependence in population growth rate in the second phase, indicating that the stabilized population was regulated. We also show density dependence in productivity (fledging success between years and hatching success within years). 4Using long-term data on behavioural interactions at nest sites, and on diet and fish provisioning rate, we evaluated two possible mechanisms of density dependence in productivity, food depletion and behavioural interference. 5As density increased, both provisioning rate and the size of prey increased, contrary to predictions of a food-depletion mechanism. In the time series, a reduction in fledging success coincided with an increase in the number of non-breeders. Hatching success decreased with increasing local density and frequency of interactions with conspecifics, suggesting that behavioural interference was influencing hatching success. 6Our study shows that, taking into account the role of non-breeders, in particular in species or populations where there are many floaters and where competition for nest sites is intense, can improve our understanding of density-dependent processes and help conservation actions. [source]

    How helpers help: disentangling ecological confounds from the benefits of cooperative breeding

    JOURNAL OF ANIMAL ECOLOGY, Issue 3 2008
    JONATHAN WRIGHT
    Evolutionary explanations for helping in cooperative breeding systems usually require a positive effect of helping on the fitness of the breeders being assisted. However, such helper effects have proven surprisingly difficult to quantify. Cockburn et al. (this issue) apply detailed statistical analyses to long-term field data on the enigmatic superb fairy-wren. They show that it is possible to disentangle the complex web of ecological and evolutionary interactions that confound so many studies. Whilst fairy-wren helpers may not increase nest productivity, they do increase future survival of breeding females. This study points the way for future statistical explorations of long-term data in other cooperative birds and mammals. [source]

    Density effects on life-history traits in a wild population of the great tit Parus major: analyses of long-term data with GIS techniques

    JOURNAL OF ANIMAL ECOLOGY, Issue 2 2006
    TEDDY A. WILKIN
    Summary 1Population density often has strong effects on the population dynamics and reproductive processes of territorial animals. However, most estimates of density-dependent effects use the number of breeding pairs per unit area in a given season and look for correlations across seasons, a technique that assigns the same density score to each breeding pair, irrespective of local spatial variation. 2In this study, we employed GIS techniques to estimate individual breeding densities for great tits breeding in Wytham Woods UK, between 1965 and 1996. We then used linear mixed modelling to analyse the effect of density on reproductive processes. 3The areas of Thiessen polygons formed around occupied nestboxes were used to approximate territory size (necessarily inverse of breeding density). There were significant, independent and positive relationships between clutch size, fledging mass and the number of offspring recruited to the population, and territory size (all P < 0·001), but no effect of territory size on lay-date or egg mass. 4Thiessen polygons are contiguous and cover all of the available area. Therefore, at low nest densities territory polygons were excessively oversized. Using a novel procedure to address this limitation, territory sizes were systematically capped through a range of maxima, with the greatest effect in the models when territories were capped at 0·9,2·3 ha. This figure approximates to the maximum effective territory size in our population and is in close agreement with several field-based studies. This capping refinement also revealed a significant negative relationship between lay-date and territory size capped at 0·9 ha (P < 0·001). 5These density-dependent effects were also detected when analyses were restricted to changes within individual females, suggesting that density effects do not merely result from either increased proportions of low-quality individuals, or increased occupation of poor sites, when population density is high. 6Overall, these results suggest that, in the current population, great tits with territories smaller than c. 2 ha independently lay smaller and later clutches, have lighter fledglings, and recruit fewer offspring to the breeding population. These analyses thus suggest a pervasive and causal role of local population density in explaining individual reproductive processes. [source]

    On the relation between temporal variability and persistence time in animal populations

    JOURNAL OF ANIMAL ECOLOGY, Issue 6 2003
    Pablo Inchausti
    Summary 1The relationship between temporal variability, spectral redness and population persistence for a large number of long-term time series was investigated. Although both intuition and theory suggest that more variability in population abundance would mean greater probability of extinction, previous empirical support for this view has not been conclusive. Possible reasons are the shortage of long-term data and the difficulties of adequately characterizing temporal variability, two issues that are explicitly addressed in this paper. 2We examined the relationship between population variability and quasi-extinction time (measured as the time required to observe a 90% decline of population abundance) for a large set of data comprising 554 populations for 123 species that were censused for more than 30 years. Two aspects of temporal variability were considered in relation with the quasi-extinction time: a baseline value (coefficient of variation over a fixed, 30-year, time scale), and a measure of the rate of increase of the population variability over time (spectral exponent). 3The results show that the quasi-extinction time was shorter for populations having higher temporal variability and redder dynamics. The relation between persistence time and population variability was compared for different taxa, trophic levels, habitat type (aquatic and terrestrial) and body sizes and compared with theoretical expectations. [source]

    Patterns of reproductive effort and success in birds: path analyses of long-term data from European ducks

    JOURNAL OF ANIMAL ECOLOGY, Issue 2 2002
    Peter Blums
    Summary 1We tested ecological hypotheses about timing of breeding and reproductive effort in birds, by analysing > 15-year data sets for individually marked females in three species of Latvian ducks (northern shoveler, tufted duck, common pochard). 2Duckling survival and recruitment declined with advancing hatch date in pochard and tufted duck, after controlling for effects of female age and other factors with path analysis, a novel finding which indicates that fitness advantages associated with early hatching extended beyond the prefledging period. Logistic regression analysis suggested further that individual duckling prefledging survival was moderate in the earliest phase of the breeding season, greatest in mid-season and lowest later on. 3However, selection acting against early hatched ducklings was surpassed by strong directional selection favouring recruitment of the earliest hatching females. The absolute and relative numbers of female recruits produced by a breeding female declined sharply with advancing hatch date in all species. 4Unlike previous studies, an hypothesized intraspecific trade-off between duckling mass and brood size was detected, being very robust in two of three species. 5Unexpectedly, female age effects on recruitment were manifested only indirectly by several pathways, the most important being the earlier hatching dates of older females. Size-adjusted body mass (i.e. condition index) was positively related to reproductive success, and was 2,8-fold more influential than female size (indexed by wing length). 6Overall, fecundity-independent variables (e.g. hatching date, weather, indices of duckling production and habitat quality) generally had 2,10 times greater influence on recruitment rates than did fecundity-dependent variables such as female size or condition, duckling mass and brood size, suggesting a critical role for external environmental factors vs. individual female-specific traits in the recruitment process. [source]

    Linking resources with demography to understand resource limitation for bears

    JOURNAL OF APPLIED ECOLOGY, Issue 6 2007
    MELISSA J. REYNOLDS-HOGLAND
    Summary 1,Identifying the resources that limit growth of animal populations is essential for effective conservation; however, resource limitation is difficult to quantify. Recent advances in geographical information systems (GIS) and resource modelling can be combined with demographic modelling to yield insights into resource limitation. 2,Using long-term data on a population of black bears Ursus americanus, we evaluated competing hypotheses about whether availability of hard mast (acorns and nuts) or soft mast (fleshy fruits) limited bears in the southern Appalachians, USA, during 1981,2002. The effects of clearcutting on habitat quality were also evaluated. Annual survival, recruitment and population growth rate were estimated using capture,recapture data from 101 females. The availability of hard mast, soft mast and clearcuts was estimated with a GIS, as each changed through time as a result of harvest and succession, and then availabilities were incorporated as covariates for each demographic parameter. 3,The model with the additive availability of hard mast and soft mast across the landscape predicted survival and population growth rate. Availability of young clearcuts predicted recruitment, but not population growth or survival. 4,Availability of hard mast stands across the landscape and availability of soft mast across the landscape were more important than hard mast production and availability of soft mast in young clearcuts, respectively. 5,Synthesis and applications. Our results indicate that older stands, which support high levels of hard mast and moderate levels of soft mast, should be maintained to sustain population growth of bears in the southern Appalachians. Simultaneously, the acreage of intermediate aged stands (10,25 years), which support very low levels of both hard mast and soft mast, should be minimized. The approach used in this study has broad application for wildlife management and conservation. State and federal wildlife agencies often possess long-term data on both resource availability and capture,recapture for wild populations. Combined, these two data types can be used to estimate survival, recruitment, population growth, elasticities of vital rates and the effects of resource availability on demographic parameters. Hence data that are traditionally used to understand population trends can be used to evaluate how and why demography changes over time. [source]

    Incidence of Hip and Other Osteoporotic Fractures in Elderly Men and Women: Dubbo Osteoporosis Epidemiology Study,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2004
    Kevin P Chang
    Abstract In this prospective 12-year study in men and women 60 years of age and older, there was a 4,6% per year reduction in the incidence rate of overall osteoporotic fractures, but the study was unable to exclude any change in the hip fracture incidence rate. Approximately one-half of hip fractures occurred before 80 years in men and two-thirds before 85 years in women. The age distribution of hip fractures underlines the need for earlier intervention in osteoporosis. Introduction: Although hip fracture is the major osteoporotic fracture in terms of health outcomes, quality of life, and costs, there is a paucity of long-term data on secular changes in men and women within a defined community. This long-term prospective population-based study over 12 years from 1989 to 2000 specifically examined the age distribution and secular changes in the incidence rates of hip and other osteoporotic fractures in men and women 60 years of age and older in a predominantly white population in Dubbo, Australia. Materials and Methods: Hip and all other clinical fractures were ascertained by reviewing all radiography reports from the two area radiology services, ensuring complete ascertainment of all clinical osteoporotic fractures. Results and Conclusion: Among the 1055 symptomatic atraumatic fractures (after excluding pathological fractures), there was a significant reduction in the overall fracture incidence rate in women (4% per year; p = 0.0003) and men (6% per year; p = 0.0004) over the 12 years. There were 229 hip fractures (175 in women and 54 in men) within 39,357 person-years of observation. The overall rate ± SE of hip fracture was 759 ± 57 per 100,000 person-years in women and 329 ± 45 per 100,000 person-years in men, with an exponential increase with age. With advancing age, the incidence rate of hip fractures in men approached that in women; the female:male ratio fell from 4.5 (95% CI: 1.3,15.7) to 1.5 (0.9,2.5) and 1.9 (1.2,2.8) in the 60,69, 70,79, and 80+ year age groups, respectively. In women, the absolute number of fractures and incidence rate continuously increased with age; however, in men, the absolute number of hip fractures peaked at 80,84 years of age and then decreased. Most importantly, despite the continuing increase with age, almost one-half (48%) of the hip fractures occurred before the age of 80 years in men, and 66% of hip fractures occurred before the age of 85 years in women. The overall hip fracture incidence is comparable with other white (except Sweden) and Asian groups as well as two other Australian studies. This study could not exclude a change in hip fracture incidence rate, even in those 80 years of age and over among whom the incidence of hip fractures was the highest. The incidence data highlight the fact that a large proportion of hip fractures occurs in those under 80 years of age, particularly in men. This age distribution underlines the need for earlier intervention in osteoporosis in women and particularly in men to achieve the most cost-effective outcomes. [source]

    The Forest-Streamflow Relationship in China: A 40-Year Retrospect,

    JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 5 2008
    Xiaohua Wei
    Abstract:, The relationship between forests and streamflows has long been an important research interest in China. The purpose of this paper is to summarize progress and lessons learned from the forest-streamflow studies over the past four decades in China. To better measure the research gaps between China and other parts of the world, a brief global review on the findings from paired watershed studies over the past 100 years was also provided. In China, forest management shifted in the later 1990s from timber harvesting to forest restoration. Forest-streamflow research was accordingly changed from assessing harvesting impacts to evaluating both harvesting and forestation effects. Over the past four decades, Chinese forest hydrology research has grown substantially. Significant progress has been made on measuring individual processes, but little solid, long-term data were available to assess the relationship between forest changes and streamflows because of an absence of standard paired watersheds. In addition, misuse of statistical analyses was often found in the literature. A unique opportunity exists in China to study the forestation effects on streamflow as several large-scale forestation programs are being implemented. Such an opportunity should include a robust paired watershed design under an integrated watershed ecosystem framework to avoid repeating the lessons already learned. Recommendations on future forest-streamflow research directions in China are provided. [source]

    Combining etanercept with traditional agents in the treatment of psoriasis: a review of the clinical evidence

    JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 10 2010
    PA Foley
    Abstract Psoriasis is a chronic, systemic inflammatory disorder manifesting primarily in skin and potentially in joints, frequently necessitating treatment with conventional systemic therapies, phototherapy or biological agents. Patients with moderate to severe disease suffer a diminished quality of life, experience significant comorbidities and have a higher mortality. Although traditional treatments are effective in the short-term, their use is often limited by concerns over long-term toxicity, including end-organ damage and risk of malignancy. Combination therapy is a commonly used approach and is often more effective than any single agent. Lower doses of two treatments in combination can also minimize potential side effects from a single agent at higher doses. Etanercept is a recombinant human tumour necrosis factor (TNF), receptor (p75) protein fused with the Fc portion of IgG1 that binds to TNF,. This article reviews the evidence on the efficacy and safety of etanercept in combination with methotrexate, acitretin, narrowband UVB and cyclosporin. The largest body of evidence assesses the combination with methotrexate, although evidence is available for the other combinations. Data suggest that although highly effective as monotherapy, etanercept in combination with a conventional systemic agent can enhance efficacy and allow drug sparing. Potentially, the combination may also result in faster treatment responses and permit safe transitioning from one systemic agent to another. Evidence to date suggests that these benefits can be achieved without significant additional toxicity, although long-term data on the efficacy and safety of the combination in psoriatic populations is limited and further evaluation is warranted. [source]

    Demographic and life-history correlates for Amazonian trees

    JOURNAL OF VEGETATION SCIENCE, Issue 6 2005
    Henrique E.M. Nascimento
    Abstract Questions: Which demographic and life-history differences are found among 95 sympatric tree species? Are there correlations among demographic parameters within this assemblage? Location: Central Amazonian rain forest. Methods: Using long-term data from 24 1,ha permanent plots, eight characteristics were estimated for each species: wood density, annual mortality rate, annual recruitment rate, mean stem diameter, maximum stem diameter, mean stem-growth rate, maximum stem-growth rate, population density. Results: An ordination analysis revealed that tree characteristics varied along two major axes of variation, the major gradient expressing light requirements and successional status, and the second gradient related to tree size. Along these gradients, four relatively discrete tree guilds could be distinguished: fast-growing pioneer species, shade-tolerant sub-canopy species, canopy trees, and emergent species. Pioneers were uncommon and most trees were canopy or emergent species, which frequently had low mortality and recruitment. Wood density was negatively associated with tree mortality, recruitment, and growth rates when all species were considered. Growth rates varied markedly among and within species, with pioneers exhibiting far faster and less variable growth rates than did the other species. Slow growth in subcanopy species relative to canopy and emergent trees was not a simple consequence of mean tree size, but apparently resulted from physiological constraints imposed by low-light and other conditions in the forest understorey. Conclusions: Trees of Amazonian rain forests could be classified with some success into four relatively distinctive guilds. However, several demographic and life-history traits, such as those that distinguish early and late successional species, probably vary along a continuum, rather than being naturally grouped into relatively discrete categories. [source]

    Rodents, plants, and precipitation: spatial and temporal dynamics of consumers and resources

    OIKOS, Issue 3 2000
    S. K. Morgan Ernest
    Resource/consumer dynamics are potentially mediated by both limiting resources and biotic interactions. We examined temporal correlations between precipitation, plant cover, and rodent density, with varying time lags using long-term data from two sites in the Chihuahuan desert of North America: the Sevilleta Long-term Ecological Research site (LTER), New Mexico, USA and a site near Portal, Arizona, USA. We also calculated the spatial correlations in precipitation, plant cover, and rodent dynamics among six sites, five at Sevilleta and one at Portal. At Sevilleta, all three variables were temporally correlated, with plant cover responding to precipitation during the same growing season and rodent populations lagging at least one season behind. At Portal, plant stem count was also correlated with precipitation during the same growing season, but there was no significant correlation between rodents and either precipitation or plant growth. Spatial correlations in plant cover and rodent populations between sites reflected the localized nature of summer rainfall, so that sites with highly correlated summer precipitation exhibited higher correlations in plant cover and rodent populations. In general, our results indicate that limiting resources influence consumer dynamics, but these dynamics also depend crucially on the biotic interactions in the system. [source]

    Exploring cultural drivers for wildlife trade via an ethnoprimatological approach: a case study of slender and slow lorises (Loris and Nycticebus) in South and Southeast Asia

    AMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2010
    K.A.I. Nekaris
    Abstract Illegal and unsustainable trade in wildlife is a major conservation challenge. For Asian primates, economic and cultural traditions, and increased forest access mean that trade may have become detrimental for certain species. Slow and slender lorises (Nycticebus and Loris) are primates particularly prevalent in trade, determined until now by focused counts of lorises in regional markets. Here, we use international trade statistics and a participant,observer approach to assess culturally specific drivers for trade in lorises in South and Southeast Asia, to provide a broader context to help mitigate this practice. Analysis of international records for the last 30 years revealed that live animal trade was more prevalent than trade in body parts (slow lorises, 86.4%; slender lorises, 91.4%), with Laos, Cambodia, and Thailand the largest exporters. We then examine drivers of international and domestic trade based on long-term data from 1994,2009 in Sri Lanka, Cambodia, and Indonesia. We show that slender lorises are important in Sri Lankan folklore, but their use as pets and for traditional medicine is rare. Trade in Bengal slow and pygmy lorises in Cambodia for use in traditional medicines, a practice with deeply historical roots, is widespread. Despite its own set of myths about the magical and curative properties of lorises, trade in Javan, Bornean, and greater slow lorises in Indonesia is largely for pets. Conservation practices in Asia are often generalized and linked with the region's major religions and economies. We show here that, in the case of wildlife trade, culturally specific patterns are evident among different ethnic groups, even within a country. Revealing such patterns is the foundation for developing conservation management plans for each species. We suggest some participatory methods for each country that may aid in this process. Am. J. Primatol. 72:877,886, 2010. © 2010 Wiley-Liss, Inc. [source]

    Litter size and infant survivorship in wild groups of cotton-top tamarins (Saguinus oedipus) in Colombia

    AMERICAN JOURNAL OF PRIMATOLOGY, Issue 8 2009
    A. Savage
    Abstract Cotton-top tamains (Saguinus oedipus) are a critically endangered primate found only in Colombia. Efforts to conserve this species are centered on developing effective management plans that integrate biological information regarding population dynamics and factors that influence their survival. This study documented infants born to wild cotton-top tamarin females from 1994,2008 at two distinct field sites in northern Colombia. Our studies have shown that wild cotton-top tamarins typically give birth to one litter each year and infant survival to 6 months of age was greater in the wild than has been reported in captive colonies. However, similar to reports from captive colonies, litter size of wild cotton-top tamarins ranges from 1,3 infants, with twin litters most common. Here we report the first occurrence of triplet litters in nearly 20 years of observing wild cotton-top tamarin groups. Over the first 3 months of life, wild-born infants exhibited highest mortality during the first week of life, similar to reports from captive colonies. Infant survival in the wild also increases with successive litters as it does in captivity. However, inter-birth interval, group size, and the number of adult males in the group did not appear to influence infant survival in the wild. The value of such long-term data from field studies aids in the information that can be used to model future population trends and develop effective conservation plans for this critically endangered primate. Am. J. Primatol. 71:707,711, 2009. © 2009 Wiley-Liss, Inc. [source]

    Surgical management of extracranial carotid artery aneurysms

    ANZ JOURNAL OF SURGERY, Issue 4 2009
    Anwar S. Choudhary
    Abstract Extracranial carotid artery aneurysms are uncommon and not much is known about them. The purpose of this study is to report the authors' surgical experience and present a review of this entity. This single institution experience shows that resection of these aneurysms and restoration of flow can be accomplished using a number of surgical techniques with relatively low morbidity and mortality. Endovascular techniques are also increasingly being considered in the repair of these aneurysms, although long-term data from such techniques are not currently available. [source]