Environmental Characteristics (environmental + characteristic)

Distribution by Scientific Domains
Distribution within Life Sciences

Selected Abstracts

Environmental and geographic correlates of the taxonomic structure of primate communities

Jason M. Kamilar
Abstract Previous research has shown that both environmental and historical factors influence the taxonomic structure of animal communities; yet, the relative importance of these effects is not known for primates. Environmental characteristics shape the possible niches in a community, providing suitable habitats for some species and not others. Therefore, communities found in similar environments should display similar species compositions. Additionally, geography may be viewed as a surrogate for historical processes. For instance, as the geographic distance between communities increases, dispersal between sites is more limited, and the probability of historical vicariance increases. Therefore, communities in close proximity to each other should exhibit similar species compositions. The geographic location, environmental characteristics, and species composition of 168 primate communities were gathered from the literature. Canonical correspondence analyses were conducted to examine the relative effects of geographic distance and environmental variables on the taxonomic structure of communities. In addition, UPGMA cluster analyses were conducted to better visualize the taxonomic similarity of communities. Spatial variables were significant predictors of community structure in all regions. Rainfall patterns explained African, Malagasy, and Neotropical community structure. In addition, maximum temperature was also correlated with community structure in Madagascar and the Neotropics. No climatic variables predicted Asian community structure. These results demonstrate that both historical and environmental factors play a significant role in structuring modern primate communities; yet, the importance of environmental factors depend on the region in question. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source]

Land-use legacies in a central Appalachian forest: differential response of trees and herbs to historic agricultural practices

James M. Dyer
Abstract Question: Are contemporary herb and tree patterns explained by historic land use practices? If so, are observed vegetation patterns associated with life-history characteristics, soil properties, or other environmental variables? Location: Southeastern Ohio, USA. Methods: Using archival records, currently forested sites were identified with distinct land use histories: cultivated, pasture (but not plowed), and reference sites which appear to have never been cleared. Trees were recorded by size and species on twenty 20 m × 20 m plots; percent cover was estimated for each herb species in nested 10 m × 10 m plots. Environmental characteristics were noted, and soil samples analysed for nutrient availability and organic matter. Nonmetric multidimensional scaling ordination was performed separately on both tree and herb datasets to graphically characterize community composition among plots. Life-history traits were investigated to explain observed compositional differences. Results: Vegetation patterns were explained by current environmental gradients, especially by land-use history. Cultivated and pasture sites had similar tree composition, distinct from reference sites. Herb composition of pasture and reference sites was similar and distinct from cultivated sites, suggesting the ,tenacity' of some forest herbs on formerly cleared sites. Tilling removes rhizomatous species, and disfavors species with unassisted dispersal. These life-history traits were underrepresented on cultivated sites, although ant-dispersed species were not. Conclusions: Historic land-use practices accounted for as much variation in species composition as environmental gradients. Furthermore, trees and herbs responded differently to past land-use practices. Life-history traits of individual species interact with the nature of disturbance to influence community composition. [source]

Using GIS, Genetic Algorithms, and Visualization in Highway Development

Manoj K. Jha
A model for highway development is presented, which uses geographic information systems (GIS), genetic algorithms (GA), and computer visualization (CV). GIS serves as a repository of geographic information and enables spatial manipulations and database management. GAs are used to optimize highway alignments in a complex search space. CV is a technique used to convey the characteristics of alternative solutions, which can be the basis of decisions. The proposed model implements GIS and GA to find an optimized alignment based on the minimization of highway costs. CV is implemented to investigate the effects of intangible parameters, such as unusual land and environmental characteristics not considered in optimization. Constrained optimization using GAs may be performed at subsequent stages if necessary using feedback received from CVs. Implementation of the model in a real highway project from Maryland indicates that integration of GIS, GAs, and CV greatly enhances the highway development process. [source]

A rapid technique for assessing the suitability of areas for invasive species applied to New Zealand's rivers

Cathy Kilroy
ABSTRACT Early responses to incursions of non-indigenous species (NIS) into new areas include modelling and surveillance to define the organisms' potential and actual distributions. For well-studied invasive species, predictive models can be developed based on quantitative data describing environmental tolerances. In late 2004, an invasive freshwater diatom Didymosphenia geminata, an NIS for which we had no such quantitative data, was detected in a New Zealand river. We describe a procedure used to rapidly develop a classification of suitability for all New Zealand's rivers, based on two sources of information. First, from a review of the limited available literature and unpublished data, we determined that temperature, hydrological and substrate stability, light availability, and water pH were the most important environmental gradients determining D. geminata's broad-scale distribution and capacity for establishing and forming blooms in rivers. The second information source was a GIS-based river network developed for a national classification of New Zealand's rivers, with associated data describing environmental characteristics of each section of the network. We used six variables that were available for every section of the network as surrogates for the environmental gradients that determine suitability. We then determined the environmental distance of all the river sections in the network from our assessment of the optimal conditions conducive to D. geminata blooms. The analysis suggested that > 70% of New Zealand's river sections (stream order > 3) fell into the two highest suitability categories (on a five-point scale). At the time of writing, D. geminata had spread to 12 catchments, all of which were within these two categories. The technique is applicable in initial responses to incursions of NIS where quantitative information is limited, and makes optimal use of available qualitative information. Our assessment contributed to evaluations of the potential ecological, social, and economic impacts of D. geminata and is currently being used to stratify site selection for ongoing surveillance. [source]

Spread and current potential distribution of an alien grass, Eragrostis lehmanniana Nees, in the southwestern USA: comparing historical data and ecological niche models

Heather Schussman
ABSTRACT The potential distribution of alien species in a novel habitat often is difficult to predict because factors limiting species distributions may be unique to the new locale. Eragrostis lehmanniana is a perennial grass purposely introduced from South Africa to Arizona, USA in the 1930s; by the 1980s, it had doubled its extent. Based on environmental characteristics associated with its introduced and native range, researchers believed that E. lehmanniana had reached the limits of its distribution by the early 1990s. We collected data on E. lehmanniana locations from various land management agencies throughout Arizona and western New Mexico and found new records that indicate that E. lehmanniana has continued to spread. Also, we employed two modelling techniques to determine the current potential distribution and to re-investigate several environmental variables related to distribution. Precipitation and temperature regimes similar to those indicated by past research were the most important variables influencing model output. The potential distribution of E. lehmanniana mapped by both models was 71,843 km2 and covers a large portion of southeastern and central Arizona. Logistic regression (LR) predicted a potential distribution of E. lehmanniana more similar to this species current distribution than GARP based on average temperature, precipitation, and grassland species composition and recorded occurrences. Results of a cross-validation assessment and extrinsic testing showed that the LR model performed as well or better than GARP based on sensitivity, specificity, and kappa indices. [source]

Regional and local influence of grazing activity on the diversity of a semi-arid dung beetle community

Jorge M. Lobo
ABSTRACT This study analyses the effect of resource availability (i.e. sheep dung) on dung beetle communities in an arid region of Central Spain, both at regional and at local scales. A total of 18 sites within 600 km2 were sampled for the regional analysis and 16 sites within the 30 km2 of an Iberian municipality were sampled for the local analysis. Spatial and environmental characteristics of sampling sites were also compiled at both scales, including measures of grazing activity (livestock density at regional scale, and two counts of rabbit and sheep dung at local scale). At a regional scale, any environmental or spatial variable can help to explain the variation in abundance. However, species richness was related to summer precipitation and composition was related to elevation. At local scale, abundance is not significantly related to any of the environmental variables, but species richness was related to the local amount of sheep dung (27% of variance). The amount of dung in a 2-km buffer around the site accounts for 27,32% of variance in abundance and 60,65% of variance in species richness. The presence of the flock with the highest sheep density explains 53% of abundance variability and 73% of species richness variance. A cluster analysis of localities identified two main groups, one characterized by a lower abundance and species richness that can be considered a nested subsample of the species-rich group. The mean and maximum amount of sheep dung in the sites separated by less than 2 km are the only significant explanatory variables able to discriminate both groups. These results suggest that grazing intensity (and the associated increase in the amount of trophic resources) is a key factor in determining local variation in the diversity and composition of dung beetle assemblages. However, dung beetle assemblages are not spatially independent at the analysed resolution, and the amount of dung in the surroundings seems to be more important for locally collected species than the dung effectively found in the site. Although differences in the availability and quantity of trophic resources among nearby sites could be affecting the population dynamics and dispersion of dung beetles within a locality, sites with larger populations, and greater species numbers would not be able to exercise enough influence as to bring about a complete local faunistic homogenization. [source]

Streamlining ,search and destroy': cost-effective surveillance for invasive species management

Cindy E. Hauser
Abstract Invasive species surveillance has typically been targeted to where the species is most likely to occur. However, spatially varying environmental characteristics and land uses may affect more than just the probability of occurrence. Biodiversity or economic value, and the ease of detection and control are also likely to vary. We incorporate these factors into a detection and treatment model of a low-density invader to determine the surveillance strategy that minimizes expected management costs. Sites with a high probability of invader occurrence and great benefits associated with detection warrant intensive surveillance; however, the optimum investment is a nonlinear function of these factors. Environments where the invader is relatively easy to detect are prioritized for surveillance, although only a moderate investment is necessary to ensure a high probability of detection. Intensive surveillance effort may be allocated to other sites if the probability of occurrence, budget and/or expected benefits is sufficiently high. [source]

Population dynamics of insects associated with Rumex obtusifolius in different habitats

Ohseok KWON
Abstract The effect of different habitats on insect communities associated with Rumex obtusifolius was studied in detail. Study sites were selected for their variety of environmental characteristics (vegetation and habitat): shaded woodland, disturbed wasteland and pasture. The results of this study were that insect populations associated with R. obtusifolius responded differently to the different habitats. The observed differences in population dynamics among the insects showed quite clearly their responses to different habitats. There was also a pattern of time partitioning in the exploitation of the host-plant among the insect species observed. Philaenus spumarius at nymphal stage had a peak density on approximately 20 June, Apion frumentarium and Apion spp. (Apion species other than A. frumentarium) had a peak density on approximately 30 June and Aphis rumicis had a peak density on approximately 28 July. This pattern of shift in time for peak population density (time-shift) among the insects sharing a common host-plant may guarantee each insect the opportunity to exploit the plant to a maximum. [source]

Faunal makeup of wild bees and their flower utilization in a semi-urbanized area in central Japan

Abstract The species composition of wild bees and their flower utilization patterns were surveyed from April to November in 1996 in a semi-urbanized area adjacent to Sugao Marsh, Ibaraki, central Japan. A total of 750 individuals belonging to 43 species in six families were collected. The most dominant family was Halictidae, for which 13 species and 251 individuals were collected. The most dominant species was Colletes patellatus (120 individuals) of the Colletidae. The results at Sugao were compared with those obtained from three other areas of Ibaraki Prefecture, which have similar climatic conditions, yet have different environmental characteristics in terms of human impact. The four sites in Ibaraki can be classified into two groups: the first comprising Sugao and Mito in cultivated and/or human-dwelling areas, and the second comprising Yamizo and Gozen'yama, in forest areas with more natural elements. The number of species at Sugao was the smallest among the four study sites. On the other hand, the values for species evenness at Sugao were the second-highest of the four study sites. These findings show that the different characteristics of different bee communities reflect their local environmental conditions, including their floral compositions. The bees visited 36 flower species in 20 families, and 70.7% of all individuals studied visited Compositae flowers. The heavy utilization of composite flowers is possibly because of the existence of a simplified flora consisting of a few dominant composite plant species. Among these plants, Solidago altissima and Lactuca indica made large contributions to supporting autumn bees, especially Colletes patellatus and Colletes perforator, which are solitary and oligolectic on Compositae. [source]

Cessation of periodontal care during pregnancy: effect on infant birthweight

Philippe P. Hujoel
The goal of this study was to assess whether interruption of care for chronic periodontitis during pregnancy increased the risk of low-birthweight infants. A population-based case-control study was designed with 793 cases (infants <,2,500 g) and a random sample of 3,172 controls (infants ,,2,500 g). Generalized estimating equation models were used to relate periodontal treatment history to low birthweight risk and to common risk factors. The results indicate that periodontal care utilization was associated with a 2.35-fold increased odds of self-reported smoking during pregnancy (95% confidence interval: 1.48,3.71), a 2.19-fold increased odds for diabetes (95% confidence interval: 1.21,3.98), a 3.90-fold increased odds for black race (95% confidence interval: 2.31,6.61), and higher maternal age. After adjustment for these factors, interruption of periodontal care during pregnancy did not lead to an increased risk for a low-birthweight infant when compared to women with no history of periodontal care (odds ratio, 0.96; 95% confidence interval, 0.60,1.52). In conclusion, women receiving periodontal care had genetic and environmental characteristics, such as smoking, diabetes and race, that were associated with an increased risk for low-birthweight infants. Periodontal care patterns, in and of themselves, were unrelated to low-birthweight risk. [source]

Contribution of native and non-native species to fish communities in French reservoirs

P. Irz
Abstract Previous studies showed that only 20% of the variability in fish community structure in French reservoirs could be explained by site characteristics. In addition, no relationship was found between the relative abundance of species and stocking effort. Therefore, deliberate or uncontrolled introductions are likely to be the source of a great part of the observed communities. The objective of this study was to assess the importance of species introductions in French reservoirs. Fifty-one reservoirs were sampled to obtain species presence/absence data. Local native (LNaR) and non-native (LNNR) species richness were negatively correlated. LNaR was strongly correlated to the lake surface area, depth and catchment area, whereas LNNR was independent of environmental variables. Furthermore, LNaR was positively correlated to regional native richness. Conversely, local total richness was independent of regional total richness, but was related to the reservoirs' environmental characteristics. It was hypothesised that the native fish communities in French reservoirs are unsaturated and species introductions lead to saturated communities. [source]

Changes in fish assemblages in catchments in north-eastern Spain: biodiversity, conservation status and introduced species

Summary 1. North-eastern Spain is a hot spot for the introduction of alien fish species, and its native fish fauna is one of the most endangered worldwide. We used an extensive data set from 2002 to 2003 and historical information from the area to characterize fish diversity and establish conservation priorities in river catchments. 2. Diversity indices were used to characterize fish diversity at the basin scale. An index of conservation status was applied for each species, which considers the occurrence, abundance and endemicity of each taxon. We used indirect ordination methods to test the relationship among basin features and to identify those variables most correlated with each other. To identify physical, biotic and environmental characteristics that seem to make a basin particularly susceptible to invasion, we performed a step-wise multiple regression to examine the relationship between the number of native, translocated and introduced fish species (including the original native species richness of each basin), and landscape variables. 3. Over a period of approximately 50 years, the mean range size of native fish species has decreased by 60%. The greatest decline occurred in Gasterosteus gymnurus, Anguilla anguilla and Salaria fluviatilis, for which species over 75% of the original distribution area has been lost. The species with the highest conservation index were Gasterosteus gymnurus and Salaria fluviatilis. 4. Basin area and the catchment type explained 70% of variation in native species richness, whereas the number of dams and basin area accounted for more than 80% of variation in the number of introduced species. 5. The original native species richness and the number of introduced species at basin scale were not related, and thus there was no evidence of "biotic resistance" to invasion. The restoration of natural hydrologic processes and the development of specific management tools to protect native species, such as the prioritization of areas for fish conservation and the eradication of local populations of exotic species, are required to restore native fish fauna in these catchments. [source]

Spatial scale and the diversity of macroinvertebrates in a Neotropical catchment

Summary 1.,Lotic ecosystems can be studied on several spatial scales, and usually show high heterogeneity at all of them in terms of biological and environmental characteristics. Understanding and predicting the taxonomic composition of biological communities is challenging and compounded by the problem of scale. Additive diversity partitioning is a tool that can show the diversity that occurs at different scales. 2.,We evaluated the spatial distribution of benthic macroinvertebrates in a tropical headwater catchment (S.E. Brazil) during the dry season and compared alpha and beta diversities at the scales of stream segments, reaches, riffles and microhabitats (substratum types: gravels, stones and leaf litter). We used family richness as our estimate of diversity. Sampling was hierarchical, and included three stream segments, two stream reaches per segment, three riffles per reach, three microhabitats per riffle and three Surber sample units per microhabitat. 3.,Classification analysis of the 53 families found revealed groups formed in terms of stream segment and microhabitat, but not in terms of stream reaches and riffles. Separate partition analyses for each microhabitat showed that litter supported lower alpha diversity (28%) than did stones (36%) or gravel (42%). In all cases, alpha diversity at the microhabitat scale was lower than expected under a null model that assumed no aggregation of the fauna. 4.,Beta diversity among patches of the microhabitats in riffles depended on substratum type. It was lower than expected in litter, similar in stone and higher in gravel. Beta diversities among riffles and among reaches were as expected under the null model. On the other hand, beta diversity observed was higher than expected at the scale of stream segments for all microhabitat types. 5., We conclude that efficient diversity inventories should concentrate sampling in different microhabitats and stream sites. In the present study, sampling restricted to stream segments and substratum types (i.e. excluding riffles and stream reaches) would produce around 75% of all observed families using 17% of the sampling effort employed. This finding indicates that intensive sampling (many riffles and reaches) in few stream segments does not result in efficient assessment of diversity in a region. [source]

An Empirical Taxonomy of Hospital Governing Board Roles

Shoou-Yih D. Lee
Objective. To develop a taxonomy of governing board roles in U.S. hospitals. Data Sources. 2005 AHA Hospital Governance Survey, 2004 AHA Annual Survey of Hospitals, and Area Resource File. Study Design. A governing board taxonomy was developed using cluster analysis. Results were validated and reviewed by industry experts. Differences in hospital and environmental characteristics across clusters were examined. Data Extraction Methods. One-thousand three-hundred thirty-four hospitals with complete information on the study variables were included in the analysis. Principal Findings. Five distinct clusters of hospital governing boards were identified. Statistical tests showed that the five clusters had high internal reliability and high internal validity. Statistically significant differences in hospital and environmental conditions were found among clusters. Conclusions. The developed taxonomy provides policy makers, health care executives, and researchers a useful way to describe and understand hospital governing board roles. The taxonomy may also facilitate valid and systematic assessment of governance performance. Further, the taxonomy could be used as a framework for governing boards themselves to identify areas for improvement and direction for change. [source]

At-sea distribution and scale-dependent foraging behaviour of petrels and albatrosses: a comparative study

Summary 1In order to study and predict population distribution, it is crucial to identify and understand factors affecting individual movement decisions at different scales. Movements of foraging animals should be adjusted to the hierarchical spatial distribution of resources in the environment and this scale-dependent response to environmental heterogeneity should differ according to the forager's characteristics and exploited habitats. 2Using First-Passage Time analysis, we studied scales of search effort and habitat used by individuals of seven sympatric Indian Ocean Procellariiform species fitted with satellite transmitters. We characterized their search effort distribution and examined whether species differ in scale-dependent adjustments of their movements according to the marine environment exploited. 3All species and almost all individuals (91% of 122 individuals) exhibited an Area-Restricted Search (ARS) during foraging. At a regional scale (1000s km), foraging ranges showed a large spatial overlap between species. At a smaller scale (100s km, at which an increase in search effort occurred), a segregation in environmental characteristics of ARS zones (where search effort is high) was found between species. 4Spatial scales at which individuals increased their search effort differed between species and also between exploited habitats, indicating a similar movement adjustment for predators foraging in the same habitat. ARS zones of the two populations of wandering albatross Diomedea exulans (Crozet and Kerguelen) were similar in their adjustments (i.e. same ARS scale) as well as in their environmental characteristics. These two populations showed a weak spatial overlap in their foraging distribution, with males foraging in more southerly waters than females in both populations. 5This study demonstrates that predators of several species adjust their foraging behaviour to the heterogeneous environment and these scale-dependent movement adjustments depend on both forager and environment characteristics. [source]

The role of group size and environmental factors on survival in a cooperatively breeding tropical passerine

Summary 1Variation in survival, a major determinant of fitness, may be caused by individual or environmental characteristics. Furthermore, interactions between individuals may influence survival through the negative feedback effects of density dependence. Compared to species in temperate regions, we have little knowledge about population processes and variation in fitness in tropical bird species. 2To investigate whether variation in survival could be explained by population size or climatic variables we used capture,recapture models in conjunction with a long-term data set from an island population of the territorial, cooperatively breeding Seychelles warbler (Acrocephalus sechellensis). The lack of migration out of the study population means that our results are not confounded by dispersal. 3Annual survival was high, both for adults (84%) and juveniles (61%), and did not differ between the sexes. Although there was significant variation in survival between years, this variation could not be explained by overall population size or weather variables. 4For territorial species, resource competition will work mainly on a local scale. The size of a territory and number of individuals living in it will therefore be a more appropriate measure of density than overall population density. Consequently, both an index of territory quality per individual (food availability) and local density, measured as group size, were included as individual covariates in our analyses. 5Local density had a negative effect on survival; birds living in larger groups had lower survival probabilities than those living in small groups. Food availability did not affect survival. 6Our study shows that, in a territorial species, although density-dependent effects might not be detectable at the population level they can be detected at the individual territory level , the scale at which individuals compete. These results will help to provide a better understanding of the small-scale processes involved in the dynamics of a population in general, but in particular in tropical species living in relatively stable environments. [source]

Effect of physical, chemical and environmental characteristics on arbuscular mycorrhizal fungi in Brachiaria decumbens (Stapf) pastures

R.H. Posada
Abstract Aim:, To evaluate the effects of soil physical and chemical factors (pH, conductivity, humidity, available phosphorus and organic matter) and environmental factors (temperature, relative air humidity, altitude and atmospheric pressure) on arbuscular mycorrhizal fungi (AMF),Brachiaria decumbens grass relationship. Furthermore to establish patterns of microbiological responses that allow to differentiate the study sites in two relief types. Methods and Results:, Mycorrhizal characteristics (spore density, external hyphae and root colonizations by hyphae, vesicles and arbuscules), physical and chemical factors in soil and environmental factors were measured. Conclusions:, The effect of physical, chemical and environmental factors on microbiological variables was related to the type of relief ,valley and hilly terrain'; the AMF behaviour was affected only over narrower ranges of evaluated variables. Similarly, the colonization of B. decumbens roots by AMF hyphae, vesicles and the mycorrhizal spore density follow different patterns according to the relief type. Significance and Impact of the Study:, The type of relief is one of the factors to be taken into consideration to evaluate the AMF inoculum and root colonization of these pastures, because of the influence of slope , as physical property of soil , on AMF. [source]

Analysis of plant species diversity with respect to island characteristics on the Channel Islands, California

Aaron Moody
Abstract Aim Species richness of native, endemic, and exotic plant groups is examined relative to island area, disturbance history, geological history, and other physical characteristics. Of particular interest are the biogeographic factors that underlie (a) differences in species-area and species-isolation relationships between plant groups; and (b) adherence or departure of individual islands and/or plant groups from expected patterns. Location The eight Channel Islands lie along the continental margin between the U.S./Mexico border and Point Conception, CA. They range in size from 2.6 to 249 km2, and are located from 20 to 100 km off the coast. The islands are known for their high degree of plant endemism, and they have undergone a long history of human occupation by indigenous peoples, followed by over a century of intensive grazing and other biotic disturbances. Methods The study is based on linear regression and residual analysis. Cases where individual islands and/or specific plant groups do not adhere to patterns expected under species-area and species-isolation paradigms, are evaluated with respect to other island characteristics that are not captured by considering only island size and isolation. Results All three plant groups exhibit strong, positive relationships between species richness and island size. For native species, the variance that remains after consideration of island size is largely explained by island isolation. For exotic species, residuals from the species-area relationship are unrelated to isolation. For endemic species, residuals from the species-area relationship are negatively related to isolation. Several islands are outliers for endemic and exotic species, for which richness values are not explained by either island area or isolation. Main,conclusions Species-area and species-isolation relationships for native, endemic, and exotic plant groups differ in accordance with hypothesized differences in the biogeographic factors that govern species diversity for these three groups. Most notably, endemic richness increases with isolation, suggesting the influence of this variable on processes of speciation and relictualism. These general relationships persist despite a long and varied history of human activity on the islands. Analysis of residuals suggests that deviations from expected patterns correspond to island-specific biogeographic factors. It is hypothesized that primary among these factors are land-use history, island environmental characteristics, and community-type richness. [source]

Use of communal roosts by Andean Condors in northwest Patagonia, Argentina

Sergio A. Lambertucci
ABSTRACT Andean Condors (Vultur gryphus) are endangered in the northern portion of their South American range, but populations are larger further south. However, throughout their range, little is known about current population sizes and dynamics. Andean Condors use cliffs with shelves as communal roosts and, from 1999 to 2001, we surveyed three of these roosts in northwestern Patagonia, Argentina, to estimate population sizes and trends. The minimum population of Andean Condors in our study area was 196, one of the highest populations recorded for this species. The maximum number of condors observed increased during our 3-yr study. However, there was a strong seasonal pattern in roost use and use also varied among roosts, possibly due to differences in their environmental characteristics, size, and room available for roosting, as well as proximity to nest sites and stage of the breeding season. In 1999 and 2000, more adults were observed than juveniles, but proportions were similar in 2001. Because we observed differential use of roosts among age classes, spatial segregation seems probable. We conclude that intensive censuses of communal roosts can provide useful information about the size, status, and dynamics of local populations. However, the large aggregations we observed may represent a potential risk for the conservation of the species because a single threat could affect multiple individuals. We suggest that a suitable conservation strategy for condors must involve the design and protection of a network of communal roosts. SINOPSIS El Cóndor Andino (Vultur gryphus) es una especie en peligro de extinción en el norte de su distribución Sudamericana, pero sus poblaciones son más abundantes hacia el sur. Sin embargo, poco se conoce sobre los tamaños de las poblaciones y sus dinámicas a lo largo de su distribución. El cóndor usa acantilados con repisas para descansar y pernoctar comunalmente a lo largo del año. Entre 1999-2001 censamos tres de estos dormideros en el noroeste de la Patagonia Argentina para estimar el tamaño poblacional y los patrones de uso. El tamaño poblacional mínimo de la especie en nuestra área de estudio fue de 196 individuos, el cual es de los más grandes registrados para el Cóndor Andino. Aunque el número máximo de cóndores aumentó durante los tres años de estudio, hubo un fuerte patrón estacional del uso de los dormideros. También encontramos variación en el uso entre dormideros posiblemente debida a las diferencias en sus características ambientales, tamaño, espacio disponible para perchar, proximidad a sitios de nidificación y la fase del período reproductivo. En 1999 y 2000 observamos más adultos que juveniles, pero las proporciones fueron similares en 2001. Observamos diferencias en el uso de cada dormidero entre estadios etarios, por lo cual es factible la segregación espacial por edades. Concluimos que los censos intensivos de dormideros comunales pueden proveer información útil sobre el tamaño, estatus y las dinámicas de las poblaciones locales. Sin embargo, grandes agregaciones como las observadas podrían representar un riesgo para la conservación de esta especie, ya que una sola una amenaza podría afectar a muchos individuos. Sugerimos que una estrategia de conservación adecuada para el Cóndor Andino debería involucrar el diseño y protección de una red de dormideros comunales. [source]

Spatial and environmental consistency in serial sexual assault

Samantha Lundrigan
Abstract This study examines the crime patterns of 76 New Zealand serial sexual offenders in order to determine the extent to which offenders display locational consistency in their choice of crime locations. More specifically, the hypothesis was that there would be intraseries consistency in the distances travelled (spatial consistency) and the characteristics of the crime sites selected (environmental consistency) by serial sexual offenders. For spatial consistency to be tested, the distances travelled from home to offend and the criminal range for each offence series were analysed. Support was found for spatial consistency, and, in line with much overseas research, it was also found that the offenders typically did not travel very far from home to offend (median distance of 3,km). The environmental consistency measure was made up of various physical, temporal, and contextual variables that described the environmental characteristics of an offence. As hypothesised, it was found that offenders displayed intraseries environmental consistency in offence site selection beyond the level of that expected by chance. The implications of this both for understanding offender spatial decision making and for geographical profiling are discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source]

An evaluation of the nursing practice environment and successful change management using the new generation Magnet Model

grant b., colello s., riehle m. & dende d. (2010) Journal of Nursing Management18, 326,331 An evaluation of the nursing practice environment and successful change management using the new generation Magnet Model Aim, To discuss the new Magnet Model as it relates to the successful implementation of a practice change. Background, There is growing international interest in the Magnet Recognition Programme. The latest generation of the Magnet Model has been designed not only as a road map for organizations seeking to achieve Magnet recognition but also as a framework for nursing practice and research in the future. Evaluation, The Magnet Model was used to identify success factors related to a practice change and to evaluate the nursing practice environment. Key issues, Even when proposed changes to practice are evidence based and thoughtfully considered, the nurses' work environment must be supportive and empowering in order to yield successful and sustainable implementation of new practice. Conclusion, Success factors for implementation of a practice change can be illuminated by aligning environmental characteristics to the components of the new Magnet Model. Implications for nursing management, The Magnet Model provides an exceptional framework for building an agile and dynamic work force. Thoughtful consideration of the components and inter-relationships represented in the new model can help to both predict and ensure organizational vitality. [source]

A Unique Set of Interactions: The MSU Sustained Partnership Model of Nurse Practitioner Primary Care

FNP Assistant Professor, Katherine Dontje MSN
Purpose To present a unified conceptual model that identifies the integral processes of nurse practitioner (NP) care delivery and that integrates major structural influences and potential outcomes. The model is further characterized to delineate the unique and "value-added" nature of NP primary care and to describe how this nature may be correlated with specific clinical outcomes. Data Sources Extensive review of the literature, relevant conceptual models, clinical experiences of the authors, and two sets of qualitative data exploring differences between NP practice and other practices. Conclusions The basis of NP primary care is the unique provider-client relationship that develops within the primary care setting. This relationship is oriented toward (a) helping clients become empowered to more appropriately manage their own care in a way that will best meet their needs, (b) encouraging mutual decision making, (c) ensuring clients' continuity of care, and (d) providing a holistic approach to primary care. The major structural influences are NP role components, interdisciplinary practice relationships, budget resources and payer mix, and environmental characteristics. The potential outcomes are increased healthpromoting behaviors, improved utilization of care, higher client satisfaction levels, and improved health status. Implications for Practice NPs can use this model to articulate the unique contribution of NP practice and its interrelationships within the broader primary care setting. Practicing NPs can use this framework to better understand the complexities of their current and future primary care practices. Faculty can utilize the concepts to help guide students' understanding of their prospective roles as advanced practice nurses. Finally, this conceptual framework can inform research about specific NP processes and related outcomes. A clearly delineated model that accurately depicts structures, processes, and outcomes relevant to NP primary care can strengthen NP education, distinguish NP practice, and advance evidenced-based research linking NP practice and outcomes. [source]

Structure and composition of vegetation along an elevational gradient in Puerto Rico

W.A. Gould
Liogier & Martorrell (1999) Abstract Question: What are the composition, conservation status, and structural and environmental characteristics of eight mature tropical forest plant communities that occur along an elevational gradient. Location: Northeastern Puerto Rico. Methods: We quantified the species composition, diversity, conservation status, and ecological attributes of eight mature tropical forest plant communities in replicated plots located to sample representative components of important forest types occurring along an elevational gradient. A suite of environmental and vegetation characteristics were sampled at each plot and summarized to characterize communities and analyse trends along the elevational gradient. Results: The set of communities included 374 species; 92% were native, 14% endemic, and 4% critical elements (locally endangered) to the island. All communities, occurring within a wide range of patch sizes and degree of conservation protection, showed a high percentage of native species (> 89% per plot). The lowland moist forest communities, occurring within a matrix of urbanization, agriculture, and disturbance, had the highest degree of invasion by exotics. Community descriptions were nested within a variety of hierarchies to facilitate extrapolation of community characteristics to larger ecosystem units. Basal area, above-ground biomass, canopy heights, and mean species richness peaked at mid elevations. Conclusions: It is significant that all of these forest communities continue to be dominated by native species while existing in a matrix of human and natural disturbance, species invasion, and forest regeneration from widespread agriculture. The lowland moist and dry forest types represent a minority of the protected forested areas in Puerto Rico, serve as unique genetic reservoirs, and should be protected. [source]

Rationale and methods for compiling an atlas of desertification in Italy

E. A. C. Costantini
Abstract This study presents the main results and the methodology used in the creation of the atlas of the risk of desertification in Italy. A desertified area was defined as an unproductive area for agricultural or forestry use, due to soil degradation processes. An area at risk of desertification was a tract of the earth's surface which is vulnerable or sensitive to the processes of desertification. In a vulnerable land, environmental characteristics are close to that of a desertified area, but some factors (e.g. vegetation cover or irrigation), successfully mitigate the desertification process. On the other hand, sensitive land is a surface where the process leading to desertification is active, although the land is not yet unproductive. The DPSIR (Driving force-Pressure-State-Impact-Response) framework has been adopted as a reference. Using the national soil information system and socio-economic layers, an atlas of indicators of desertification risks was created, which was organized into different soil degradation systems. 51.8 per cent of Italy was considered to be at potential risk of desertification. Some 21.3 per cent of Italy (41.1 per cent of the area at potential risk) featured land degradation phenomena. Specifically, 4.3 per cent of Italy is already unproductive; 4.7 per cent is sensitive and 12.3 per cent is vulnerable. In the territory at potential risk of desertification, unproductive lands, plus areas vulnerable or sensitive to soil erosion, are at least the 19 per cent. Areas affected by aridity also sum up to 19 per cent. Salt-affected soils in Italy are estimated to cover >1 million,ha. Irrigation can mitigate soil aridity and salinization, nevertheless, only about 15 per cent of the sensitive and vulnerable lands of southern Italy are actually equipped with irrigation networks. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Agricultural trajectories in a Mediterranean mountain region (Priorat, NE Spain) as a consequence of vineyard conversion plans

R. Cots-Folch
Abstract In mountain regions of Mediterranean European countries, recent economic and technologic changes have involved the intensification of crops, based on heavy land levelling and/or terracing, and the abandonment or marginalization of traditional land use management. These trends have been reinforced by the subsidy policies of the European Union. The objectives of the present research were: (a) to contribute to the understanding of agricultural trajectories and farming systems that are entirely transforming the social and environmental characteristics of Mediterranean mountain areas, focusing on the analysis of the main agricultural trajectories in a sample area of this environment (the Priorat region, NE Spain) over the last 20 years (1986,2005); and (b) to analyse the farming systems that coexist in the region with regard to the landscape impacts they involve and the influence of CAP subsidies in each one. A methodological approach based on the combination of multivariate statistical techniques was used to obtain a better knowledge of the heterogeneity of farming systems on a local scale. The results show that, although most farms cultivate a mosaic of traditional crops and have small mechanized areas, a minority group follows a high intensification and specialization strategy based on new mechanized-terraced vineyards. This group only comprises 12 per cent of the farmers in the region, but owns 61 per cent of the new vineyard plantations and 42 per cent of the total agricultural land, receiving most of the subsidies from the EU vineyard conversion and restructuring policy (68 per cent of total Common Agricultural Policy (CAP) subsidies assigned to the region). Copyright © 2008 John Wiley & Sons, Ltd. [source]


Simon H. Elwen
Abstract Aerial surveys over the last 32 yr have shown that the distribution of southern right whales Eubalaena australis along the south coast of South Africa is markedly discontinuous, but highly predictable. A GIS was used at a variety of scales to investigate whether this pattern was related to environmental characteristics. Whale distribution was analyzed as density per 20-min bin of longitude over two temporal and spatial scales, namely 15 bins for 32 yr, and a wider scale but shorter time period, 23 bins for 19 yr, as well as using three years of GPS accuracy data (15 bins) for finer scale analysis. Environmental factors tested were depth, distance from shore, sea floor slope, protection from swell, protection from wind, and shore type. The majority of whales were concentrated in areas that provided reasonable protection from open ocean swell and seasonal winds, and had sedimentary floors with gentle slopes. They generally avoided exposed rocky shorelines. Cow-calf pairs were found significantly closer to shore and in shallower water than unaccompanied whales, particularly off sandy beaches. Habitat choice at this time of year may be related both to energy conservation for calves and lactating females (calm sea conditions) and to protection of the new-born. [source]

Incidence of acute respiratory infections and the relationship with some factors in infancy in Antalya, Turkey

Nilay Etiler
Abstract Background: Acute respiratory infections (ARI) are one of the major problems of childhood in developing countries. The objective of the study was to obtain the incidence of ARI and its risk factors in Antalya, Turkey. Methods:,We carried out a prospective cohort study on 204 infants who were born between 1 November and 31 December 1997, in the area of two primary health-care units in the Antalya city center. The research group was followed periodically every 2 months by home visits and the infants were investigated to determine their symptoms of ARI. The weight and length of children were measured in every home visit. Additional questions about socioeconomic status, some environmental characteristics, and nutrition practice were asked. Data were entered into the computer and the Z -scores were calculated by the Epi Info 5 package program. The incidence rates, relative risks and confidence intervals were calculated by Microsoft Excel version 5.0 program. Results:,The incidence of ARI was 6.53 episodes per child per year among the children in the research group. The factors that influenced the incidence of ARI were lack of mother's and father's education, heating by wood stove, being a low-birthweight infant, not being completely breast-fed in the first 4 months of life and being stunted. There were no associations between the number of persons per room or smoking status of family members with ARI incidence. Conclusion:,Our results demonstrated that ARI were also associated with some socioeconomic, environ­mental and nutritional status characteristics such as paternal education, house ownership, breast-feeding, stunting, prematurity and burning of biomass fuels in Turkey. [source]


This study employs structured interviews in a field setting to develop an in-depth understanding of how a specific human resource decision affected manufacturing performance at 30 plants using advanced manufacturing technologies. Initial results suggested that there is no relationship between the skill level of operational employees and the level of performance of the installations. When a measure of "fit" between environmental characteristics and skills was employed, however, there was a significant relationship between the fit measure and performance. [source]

Better than Raw: A Guide to Measuring Organizational Performance with Adjusted Performance Measures

Ross Rubenstein
Like oysters on the half shell, some things are better when they're raw. In evaluating the performance of organizations and providing guidance for improving performance, however, raw performance measures, such as test scores or success rates, are often inferior to performance measures adjusted for client and environmental characteristics, or adjusted performance measures (APMs). Using examples from a variety of public services and data on public schools in Georgia, we compare the performance data generated by raw scores and by APMs. We conclude with guidance for constructing and using adjusted performance measures. [source]

Environmental and geographic correlates of the taxonomic structure of primate communities

Jason M. Kamilar
Abstract Previous research has shown that both environmental and historical factors influence the taxonomic structure of animal communities; yet, the relative importance of these effects is not known for primates. Environmental characteristics shape the possible niches in a community, providing suitable habitats for some species and not others. Therefore, communities found in similar environments should display similar species compositions. Additionally, geography may be viewed as a surrogate for historical processes. For instance, as the geographic distance between communities increases, dispersal between sites is more limited, and the probability of historical vicariance increases. Therefore, communities in close proximity to each other should exhibit similar species compositions. The geographic location, environmental characteristics, and species composition of 168 primate communities were gathered from the literature. Canonical correspondence analyses were conducted to examine the relative effects of geographic distance and environmental variables on the taxonomic structure of communities. In addition, UPGMA cluster analyses were conducted to better visualize the taxonomic similarity of communities. Spatial variables were significant predictors of community structure in all regions. Rainfall patterns explained African, Malagasy, and Neotropical community structure. In addition, maximum temperature was also correlated with community structure in Madagascar and the Neotropics. No climatic variables predicted Asian community structure. These results demonstrate that both historical and environmental factors play a significant role in structuring modern primate communities; yet, the importance of environmental factors depend on the region in question. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source]