bluuebunny/crossref_metadata_2025_split huggingface dataset:
Walking function, pain, and fatigue in adults with cerebral palsy: a 7‐year follow‐up study
Authors: OPHEIM ARVE , JAHNSEN REIDUN , OLSSON ELISABETH , STANGHELLE JOHAN K 
Published: February 2009

Aim To compare walking function, pain, and fatigue in adults with cerebral palsy (CP) 7 years after an initial survey.Method A multidimensional questionnaire was mailed to 226 people with unilateral (hemiplegic) or bilateral (diplegic) spastic CP who had participated in a 1999 survey. People with additional diagnoses were excluded. Special emphasis was placed on participants with deterioration in walking. The questionnaire was the same as in 1999.Results One hundred and forty‐nine participants (76 males, 73 females; mean age 40y 5mo, SD 10y 7mo, range 24–76y) with a diagnosis of unilateral (n=81) or bilateral (n=68) spastic CP responded. Fifty‐two per cent of all participants reported deterioration in walking function since debut of walking, compared with 39% 7 years previously. In participants with bilateral CP, 71% reported deteriorated walking, compared with 37% of participants with unilateral CP. Participants with deteriorated walking function had greater pain frequency, pain intensity, impact of pain on daily activities, and physical fatigue and reduced balance. The number of people reporting overall mobility problems was almost double compared with 7 years previously.Interpretation The main finding was an increased prevalence of deteriorated walking, significantly associated with bilateral spastic CP, pain, fatigue, and reduced balance. Rehabilitation programmes addressing these areas are needed.
Reconstructing community relationships: the impact of sampling error, ordination approach, and gradient length
Authors: Hirst Claire N. , Jackson Donald A. 
Published: February 2009

ABSTRACTEffectively summarizing complex community relationships is an important feature in studies such as biodiversity, global change, and invasion ecology. The reliability of such community summaries depends on the degree of sampling variability that is present in the data, the structure of the data, and the choice of ordination method, but the relative importance of these factors is not understood. We compared the validity of results from different ordination methods by applying five levels of sampling error to a simulated coenoplane model at two gradient lengths using two types of data (abundance and presence–absence). The multivariate methods we compared were correspondence analysis (CA), detrended correspondence analysis (DCA), non‐metric multidimensional scaling (NMDS), principal component analysis (PCA) and principal coordinates analysis (PCoA). Our results showed CA and PCA using presence–absence data were the most successful methods regardless of sampling error and gradient length, closely followed by the other methods using presence–absence data. With abundance data, PCA and CA were the most successful approaches with the short and long gradients, respectively. Approaches based on PCoA and NMDS using abundance data did not perform well regardless of the choice of distance measure used in the analysis. Both of these methods, along with the PCA using abundance data, were strongly affected by the longer gradient, leading to more distorted results.
Rivers in peril inside and outside protected areas: a systematic approach to conservation assessment of river ecosystems
Authors: Nel Jeanne L. , Roux Dirk J. , Maree Gillian , Kleynhans Cornelius J. , Moolman Juanita , Reyers Belinda , Rouget Mathieu , Cowling Richard M. 
Published: February 2009

ABSTRACTThis paper establishes a framework within which a rapid and pragmatic assessment of river ecosystems can be undertaken at a broad, subcontinental scale, highlighting some implications for achieving conservation of river biodiversity in water‐limited countries. The status of river ecosystems associated with main rivers in South Africa was assessed based on the extent to which each ecosystem had been altered from its natural condition. This requires consistent data on river integrity for the entire country, which was only available for main rivers; tributaries were thus excluded from the analyses. The state of main river ecosystems in South Africa is dire: 84% of the ecosystems are threatened, with a disturbing 54% critically endangered, 18% endangered, and 12% vulnerable. Protection levels were measured as the proportion of conservation target achieved within protected areas, where the conservation target was set as 20% of the total length of each river ecosystem. Sixteen of the 112 main river ecosystems are moderately to well represented within protected areas; the majority of the ecosystems have very low levels of representation, or are not represented at all within protected areas. Only 50% of rivers within protected areas are intact, but this is a higher proportion compared to rivers outside (28%), providing some of the first quantitative data on the positive role protected areas can play in conserving river ecosystems. This is also the first assessment of river ecosystems in South Africa to apply a similar approach to parallel assessments of terrestrial, marine, and estuarine ecosystems, and it revealed that main river ecosystems are in a critical state, far worse than terrestrial ecosystems. Ecosystem status is likely to differ with the inclusion of tributaries, since options may well exist for conserving critically endangered ecosystems in intact tributaries, which are generally less regulated than main rivers. This study highlights the importance of healthy tributaries for achieving river conservation targets, and the need for managing main rivers as conduits across the landscape to support ecological processes that depend on connectivity. We also highlight the need for a paradigm shift in the way protected areas are designated, as well as the need for integrated river basin management plans to include explicit conservation visions, targets, and strategies to ensure the conservation of freshwater ecosystems and the services they provide.
A comparative evaluation of presence‐only methods for modelling species distribution
Authors: Tsoar Asaf , Allouche Omri , Steinitz Ofer , Rotem Dotan , Kadmon Ronen 
Published: February 2009

ABSTRACTIn spite of increasing application of presence‐only models in ecology and conservation and the growing number of such models, little is known about the relative performance of different modelling methods, and some of the leading models (e.g. GARP and ENFA) have never been compared with one another. Here we compare the performance of six presence‐only models that have been selected to represent an increasing level of model complexity [BIOCLIM, HABITAT, Mahalanobis distance (MD), DOMAIN, ENFA, and GARP] using data on the distribution of 42 species of land snails, nesting birds, and insectivorous bats in Israel. The models were calibrated using data from museum collections and observation databases, and their predictions were evaluated using Cohen's Kappa based on field data collected in a standardized sampling design covering most parts of Israel. Predictive accuracy varied between modelling methods with GARP and MD showing the highest accuracy, BIOCLIM and ENFA showing the lowest accuracy, and HABITAT and DOMAIN showing intermediate accuracy levels. Yet, differences between the various models were relatively small except for GARP and MD that were significantly more accurate than BIOCLIM and ENFA. In spite of large differences among species in prevalence and niche width, neither prevalence nor niche width interacted with the modelling method in determining predictive accuracy. However, species with relatively narrow niches were modelled more accurately than species with wider niches. Differences among species in predictive accuracy were highly consistent over all modelling methods, indicating the need for a better understanding of the ecological and geographical factors that influence the performance of species distribution models.
Changes of traditional agrarian landscapes and their conservation implications: a case study of butterflies in Romania
Authors: Schmitt Thomas , Rákosy László 
Published: February 2009

ABSTRACTGlobal biodiversity is decreasing as a result of human activities. In many parts of the world, this decrease is due to the destruction of natural habitats. The European perspective is different. Here, traditional agricultural landscapes developed into species‐rich habitats. However, the European biodiversity heritage is strongly endangered. One of the countries where this biodiversity is best preserved is Romania. We analyse the possible changes in Romania's land‐use patterns and their possible benefits and hazards with respect to biodiversity. As model group, we used butterflies, whose habitat requirements are well understood. We determined the ecological importance of different land‐use types for the conservation of butterflies, underlining the special importance of Romania's semi‐natural grasslands for nature conservation. We found that increasing modern agriculture and abandonment of less productive sites both affect biodiversity negatively — the former immediately and the latter after a lag phase of several years. These perspectives are discussed in the light of the integration of Romania into the European Union.
Only some like it hot — quantifying the environmental niche of the loggerhead sea turtle
Authors: Hawkes Lucy A. , Broderick Annette C. , Coyne Michael S. , Godfrey Matthew H. , Godley Brendan J. 
Published: February 2009

ABSTRACTAlthough the Atlantic waters of North America support hundreds of thousands of loggerhead sea turtles (Caretta caretta), remarkably little is known regarding their migratory ecology and habitat use. We integrate satellite tracking with remotely sensed oceanographic data to uncover two different migratory strategies used by loggerhead turtles at the northern part of their range. Most turtles travelled from the nesting beach to forage at higher latitudes in summer, before migrating south to wintering grounds in the autumn. Others moved south after nesting to forage for up to 514 days and did not make an autumn migration. Both groups utilized warm waters at the very edge of the Gulf Stream during winter: for southerly turtles obviating seasonal migration, and for northerly turtles minimizing the distance, time and energy required to reach northern areas for subsequent foraging seasons, avoiding lethally cold winter temperatures in inshore waters at the same latitude, and reducing energy costs that would be incurred within the fast‐flowing Gulf Stream. Females made long resting dives of up to 7 h 24 min, effectively hibernating during the colder months. Offshore federal waters of the USA constitute a more important habitat for both foraging and wintering turtles than previously appreciated. These areas are potential hotspots for interaction with fisheries and proposed US military training activities and should receive special monitoring efforts to fully assess the extent of overlap.
A simulation approach to determine statistical significance of species turnover peaks in a species‐rich tropical cloud forest
Authors: Bach K. , Kessler M. , Gradstein S. R. 
Published: February 2009

ABSTRACTUse of β‐diversity indices in the study of spatial distribution of species diversity is hampered by the difficulty of applying significance tests. To overcome this problem we used a simulation approach in a study of species turnover of ferns, aroids, bromeliads, and melastomes along an elevational gradient from 1700 m to 3400 m in a species‐rich tropical cloud forest of Bolivia. Three parameters of species turnover (number of upper/lower elevational species limits per elevational step, Wilson–Shmida similarity index between adjacent steps) were analysed. Significant species turnover limits were detected at 2000 (± 50) m and 3050 m, which roughly coincided with the elevational limits of the main vegetation types recognized in the study area. The taxon specificity of elevational distributions implies that no single plant group can be used as a reliable surrogate for overall plant diversity and that the response to future climate change will be taxon‐specific, potentially leading to the formation of plant communities lacking modern analogues. Mean elevational range size of plant species was 490 m (± 369). Elevational range sizes of terrestrial species were shorter than those of epiphytes. We conclude that our simulation approach provides an alternative approach for assessing the statistical significance of levels of species turnover along ecological gradient without the limitations imposed by traditional statistical approaches.
Marine longitudinal biodiversity: causes and conservation
Authors: Briggs John C. 
Published: February 2009

ABSTRACTThe horizontal temperature zones of the earth tend to restrict the latitudinal ranges of species but allow the possibility of exceedingly broad longitudinal dispersals. In the Tropical Zone, biodiversity on the continental shelves is not homogeneous but is concentrated in two conspicuous peaks, one in the Indo‐Pacific Ocean and the other in the Atlantic. The Indo‐Pacific biodiversity peak is located within a relatively small area called the East Indies Triangle. The Atlantic peak is located in the southern Caribbean Sea. Evidence that has been accumulated over the years indicates that each area functions as a centre of origin and evolutionary radiation. What are the causes of these concentrations and their present functions? A newly published model indicates a positive relationship between environmental temperature and the rate of speciation. While this helps to explain the generally high tropical diversity, and the negative relationship between diversity and latitude, it does not provide a reason for the longitudinal concentrations. But, other new research serves to substantiate previous indications of a positive relationship between speciation rate and species diversity. The existence of this positive feedback, together with some contributory factors, provides the reason why concentrations occur. The evolutionary radiation probably begins when the build‐up of species diversity reaches a critical level. The warm‐temperate biotas are derived from the tropics. Their northern longitudinal relationships tend to be minor but, in the southern hemisphere, the West Wind Drift is an important dispersal mechanism for both warm‐temperate and cold‐temperate species. The cold‐temperate biotas peaked in two areas, the North Pacific and the Antarctic; each has developed into a centre of origin. The continuous dispersal of well‐adapted species from the centres helps peripheral communities maintain diversity.
Dealing with uncertain absences in habitat modelling: a case study of a rare ground‐dwelling parrot
Authors: Gibson Lesley , Barrett Brent , Burbidge Allan 
Published: February 2009

ABSTRACTIn the development of a species distribution model based on regression techniques such as generalized linear or additive modelling (GLM/GAM), a basic assumption is that records of species presence and absence are real. However, a common concern in many studies examining species distributions is that absences cannot be inferred with certainty. This is particularly the case where the species is rare, difficult to detect and/or does not occupy all available habitat considered suitable. The western ground parrot (Pezoporus wallicus flaviventris) of southern Western Australia, Australia, is a case in point, as not only is it rare and difficult to detect, but it is also unlikely to occupy all available suitable habitat. A recent survey of ground parrots provided the opportunity to develop a predictive distribution model. As the data were susceptible to false absences, these were replaced with randomly selected ‘pseudo’ absences and modelled using GLM. As a comparison, presence‐only information was modelled using a relatively new approach, MAXENT, a machine‐learning technique that has been shown to perform comparatively well. The predictive performance of both models, as assessed by the receiver operating characteristic plot (ROC) was high (AUC > 0.8), with MAXENT performing only marginally better than the GLM. These approaches both indicated that the ground parrot prefers areas relatively high in altitude, distant from rivers, gently sloping to level habitat, with an intermediate cover of vegetation and where there is a mosaic of vegetation ages. In this case, the use of presence‐only information resulted in the identification of important environmental attributes defining the occurrence of the ground parrot, but additional factors that account for the inability of the bird to occupy all suitable habitat should be a component of model refinement.
Multiscale modelling of the drivers of rainforest boundary dynamics in Kakadu National Park, northern Australia
Authors: Banfai Daniel S. , Brook Barry W. , Bowman David M. J. S. 
Published: February 2009

ABSTRACTUnderstanding the relative importance of factors driving savanna–forest dynamics is vital as changes in the extent of tropical forests can have major impacts on global climate and carbon balance, biodiversity, and human well‐being. Comparison of aerial photographs for 50 rainforest patches in Kakadu National Park had previously revealed a landscape wide expansion of rainforest boundaries between 1964 and 2004. Here, we used generalized linear and mixed effects models to assess the role of fire, buffalo impact, and patch characteristics in determining the rate of boundary change. The analysis was conducted at both the patch scale, and within‐patch (plot) scale, to capture the different processes operating. At the patch scale, the rate of change was best explained by rainforest type and historical buffalo impact. Fire activity, patch size, and fragmentation were not important predictors of the rate of change. At the plot scale, distance from rainforest edge was the most important predictor of the probability of change, while the fragmentation and aspect of the boundary were unimportant. Rainforest expansion has occurred through a process of margin extension rather than eruption of new patches. The rainforest expansion is consistent with having been driven primarily by shifts in global change phenomena, such as increased rainfall and atmospheric CO2, rather than changes in disturbance regime. It appears that the current fire regimes are not sufficiently destructive to limit the overall expansion of the rainforest patches. Rainforest type and historical buffalo impact have mediated the rate of change at the patch scale.
Multiple pathways for invasion of anurans on a Pacific island
Authors: Christy Michelle T. , Savidge Julie A. , Rodda Gordon H. 
Published: February 2009

ABSTRACTSince 1937, thirteen species of non‐indigenous anurans have made their way to Guam. Of these, at least six have established breeding populations. Various pathways led to the introduction of these species to the island. The only anuran intentionally introduced wasChaunus marinus(formerlyBufo marinus), which was brought to Guam as a biocontrol agent.Kaloula picta, K. pulchra, Polypedates leucomystax, and probablyLitoria fallaxarrived as stowaways via maritime or air‐transport vessels.Eleutherodactylus coquiandEuhyas(formerlyEleutherodactylus)planirostrisappear to have entered Guam through the horticultural trade. Specimens ofPseudacris regillawere found among agricultural products and Christmas trees. Five species have been transported to Guam via the aquacultural trade. The importation of tilapia, milkfish, and white shrimp from China, Hong Kong, Taiwan, and the Philippines was associated with the introduction to Guam ofFejervarya cancrivora, F. limnocharissensu lato,Microhyla pulchra, Polypedates megacephalus, andSylvirana guentheri(formerlyRana guentheri). Presently, no quarantine or containment guidelines have been established for Guam's aquacultural industry.
How well do we know the Antarctic marine fauna? A preliminary study of macroecological and biogeographical patterns in Southern Ocean gastropod and bivalve molluscs
Authors: Clarke Andrew , Griffiths Huw J. , Linse Katrin , Barnes David K. A. , Crame J. Alistair 
Published: February 2009

AbstractThe aim of this study was to use data for gastropod and bivalve molluscs to determine whether the fauna of the Southern Ocean is sufficiently well known to establish robust biogeographical and macroecological patterns. We chose molluscs for this work because they have been collected by almost every biological expedition to Antarctica, and are relatively well known taxonomically. Sampling of the continental shelf fauna is reasonably full and extensive, although new species are still being described and there are significant gaps in sampling off Wilkes Land and in the Bellingshausen and Amundsen Seas. Species richness was highest in those areas that have been subject to the most intense research activity and this pattern remained even after correction for sampling intensity. The low species richness of the Southern Ocean molluscan fauna compared with many tropical sites is confirmed, and is related principally to the absence of the large number of rare taxa that characterize some tropical assemblages. There is as yet no convincing evidence for a latitudinal cline in molluscan diversity within the Southern Ocean. Multivariate analyses defined biogeographical provinces very similar to those established previously, though they also identified a number of finer‐scale sub‐provinces including a small area of high diversity off Enderby Land. Most Southern Ocean gastropods and bivalves are rare, with limited distributions; relatively few taxa have circumpolar distributions.
Where might the western Svalbard tundra be vulnerable to pink‐footed goose (Anser brachyrhynchus) population expansion? Clues from species distribution models
Authors: Wisz Mary S. , Tamstorf Mikkel P. , Madsen Jesper , Jespersen Martin 
Published: February 2009

ABSTRACTPink‐footed geese (Anser brachyrhynchus) breed in the Arctic, where their populations have doubled since the 1980s. There is concern that nesting geese disturb the fragile tundra and lead to a trophic cascade with strong top‐down effects on vegetation and soil processes. A better understanding of the distribution of geese and factors that influence nest site selection is needed to highlight potential problem areas and assess the potential for further population expansion. To help infer the importance of environmental variables on nest site selection, we built generalized additive models using nest observations collected in 2003 and 2004 from the Sassendalen valley, Svalbard, along with a suite of geographical information system explanatory predictors. The fit of the models was very high (explaining over 72% of the deviance), and predictive power to independent samples indicated useful predictions that could discriminate between presences and absence of nests very well (area under the receiver operating characteristic curves exceeded 0.88). Significant predictors of nest site selection included elevation, slope, aspect, percentage of snow cover, percentage of foraging habitat cover, and a spatial autocovariate. Spatial predictions were applied to the broader Nordenskiöldsland region of Svalbard and highlighted the importance of previously unsurveyed locations for nesting.