bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of agricultural management, sward structure and food resources on grassland field use by birds in lowland England
Authors: ATKINSON P. W. , FULLER R. J. , VICKERY J. A. , CONWAY G. J. , TALLOWIN J. R. B. , SMITH R. E. N. , HAYSOM K. A. , INGS T. C. , ASTERAKI E. J. , BROWN V. K. 
Published: September 2005

Summary

Agricultural management of grassland in lowland Britain has changed fundamentally in the last 50 years, resulting in spatial and structural uniformity within the pastoral landscape. The full extent to which these changes may have reduced the suitability of grassland as foraging habitat for birds is unknown. This study investigated the mechanisms by which these changes have impacted on birds and their food supplies.
We quantified field use by birds in summer and winter in two grassland areas of lowland England (Devon and Buckinghamshire) over 3 years, relating bird occurrence to the management, sward structure and seed and invertebrate food resources of individual fields. Management intensity was defined in terms of annual nitrogen input.
There was no consistent effect of management intensity on total seed head production, although those of grasses generally increased with inputs while forbs were rare throughout.
Relationships between management intensity and abundance of soil and epigeal invertebrates were complex. Soil beetle larvae were consistently lower in abundance, and surface‐active beetle larvae counts consistently higher, in intensively managed fields. Foliar invertebrates showed more consistent negatively relationships with management intensity.
Most bird species occurred at low densities. There were consistent relationships across regions and years between the occurrence of birds and measures of field management. In winter, there was a tendency towards higher occupancy of intensively managed fields by species feeding on soil invertebrates. In summer, there were few such relationships, although many species avoided fields with tall swards.
Use of fields by birds was generally not related to measures of seed or invertebrate food abundance. While granivorous species were perhaps too rare to detect a relationship, in insectivores the strong negative relationships (in summer) with sward height suggested that access to food may be the critical factor.
While it appears that intensification of grassland management has been deleterious to the summer food resources of insectivorous birds that use insects living within the grass sward, intensification may have been beneficial to several species in winter through the enhancement of soil invertebrates.
Synthesis and applications. We suggest that attempts to restore habitat quality for birds in grassland landscapes need to create a range of management intensities and sward structures at the field and farm scales. A greater understanding of methods to enhance prey accessibility, as well as abundance, for insectivorous birds is required.
Adapting to climate change: is there scope for ecological management in the face of a global threat?
Authors: HULME PHILIP E. 
Published: September 2005

Summary

Climate change is recognized as a major threat to the survival of species and integrity of ecosystems world‐wide. Although considerable research has focused on climate impacts, relatively little work to date has been conducted on the practical application of strategies for adapting to climate change. Adaptation strategies should aim to increase the flexibility in management of vulnerable ecosystems, enhance the inherent adaptability of species and ecosystem processes, and reduce trends in environmental and social pressures that increase vulnerability to climate variability.
Knowledge of the specific attributes of climate change likely to impact on species or habitats is central to any adaptive management strategy. Temperature is not the only climate variable likely to change as a result of anthropogenic increases in greenhouse gases. In some regions changes in precipitation, relative humidity, radiation, wind speed and/or potential evapotranspiration may be more marked than for temperature.
Uncertainty exists in the response of species and ecosystems to a given climate scenario. While climate will have a direct impact on the performance of many species, for others impacts will be indirect and result from changes in the spatiotemporal availability of natural resources. In addition, mutualistic and antagonistic interactions among species will mediate both the indirect and direct effects of climate change.
Approaches to predict species’ responses to climate change have tended to address either changes in abundance with time or in spatial distribution. While correlative models may provide a good indication of climate change impacts on abundance, greater understanding is generated by models incorporating aspects of life history, intra‐ and interspecific competition and predation. Models are especially sensitive to the uncertainty inherent in future climate predictions, the complexity of species’ interactions and the difficulties in parameterizing dispersal functions. Model outputs that have not been appropriately validated with real data should be treated with caution.
Synthesis and applications. While climate impacts may be severe, they are often exacerbated by current management practices, such as the construction of sea defences, flood management and fire exclusion. In many cases adaptation approaches geared to safeguard economic interests run contrary to options for biodiversity conservation. Increased environmental variability implies lower sustainable harvest rates and increased risks of population collapse. Climate change may significantly reduce habitat suitability and may threaten species with limited dispersal ability. In these cases, well‐planned species translocations may prove a better option than management attempts to increase landscape connectivity. Mathematical models, long‐term population studies, natural experiments and the exploitation of natural environmental gradients provide a sound basis for further understanding the consequences of climate change.
An astronomical pattern‐matching algorithm for computer‐aided identification of whale sharks Rhincodon typus
Authors: ARZOUMANIAN Z. , HOLMBERG J. , NORMAN B. 
Published: September 2005

Summary
The formulation of conservation policy relies heavily on demographic, biological and ecological knowledge that is often elusive for threatened species. Essential estimates of abundance, survival and life‐history parameters are accessible through mark and recapture studies given a sufficiently large sample. Photographic identification of individuals is an established mark and recapture technique, but its full potential has rarely been exploited because of the unmanageable task of making visual identifications in large data sets.
We describe a novel technique for identifying individual whale sharks Rhincodon typus through numerical pattern matching of their natural surface ‘spot’ colourations. Together with scarring and other markers, spot patterns captured in photographs of whale shark flanks have been used, in the past, to make identifications by eye. We have automated this process by adapting a computer algorithm originally developed in astronomy for the comparison of star patterns in images of the night sky.
In tests using a set of previously identified shark images, our method correctly matched pairs exhibiting the same pattern in more than 90% of cases. From a larger library of previously unidentified images, it has to date produced more than 100 new matches. Our technique is robust in that the incidence of false positives is low, while failure to match images of the same shark is predominantly attributable to foreshortening in photographs obtained at oblique angles of more than 30°.
We describe our implementation of the pattern‐matching algorithm, estimates of its efficacy, its incorporation into the new ECOCEAN Whale Shark Photo‐identification Library, and prospects for its further refinement. We also comment on the biological and conservation implications of the capability of identifying individual sharks across wide geographical and temporal spans.
Synthesis and applications. An automated photo‐identification technique has been developed that allows for efficient ‘virtual tagging’ of spotted animals. The pattern‐matching software has been implemented within a Web‐based library created for the management of generic encounter photographs and derived data. The combined capabilities have demonstrated the reliability of whale shark spot patterns for long‐term identifications, and promise new ecological insights. Extension of the technique to other species is anticipated, with attendant benefits to management and conservation through improved understanding of life histories, population trends and migration routes, as well as ecological factors such as exploitation impact and the effectiveness of wildlife reserves.
Spatial and temporal patterns of species richness in a riparian landscape
Authors: Renöfält Birgitta Malm , Nilsson Christer , Jansson Roland 
Published: September 2005

AbstractAim  To test for control of vascular plant species richness in the riparian corridor by exploring three contrasting (although not mutually exclusive) hypotheses: (1) longitudinal patterns in riparian plant species richness are governed by local, river‐related processes independent of the regional species richness, (2) riparian plant species richness is controlled by dispersal along the river (longitudinal control), and (3) the variation in riparian plant species richness mirrors variation in regional richness (lateral control).Location  The riparian zones of the free‐flowing Vindel River and its surrounding river valley, northern Sweden.Methods  We used data from three surveys, undertaken at 10‐year intervals, of riparian reaches (200‐m stretches of riverbank) spanning the entire river. In addition, we surveyed species richness of vascular plants in the uplands adjacent to the river in 3.75‐km2 large plots along the same regional gradient. We explored the relationship between riparian and upland flora, and various environmental variables. We also evaluated temporal variation in downstream patterns of the riparian flora.Results  Our results suggest that local species richness in boreal rivers is mainly a result of local, river‐related processes and dispersal along the corridor. The strongest correlation between species richness and the environment was a negative one between species number and soil pH, but pH varied within a narrow range. We did not find evidence for a correlation between species richness on regional and local scales. We found that the local patterns of species richness for naturally occurring vascular plants were temporally variable, probably in response to large‐scale disturbance caused by extreme floods. Most previous studies have found a unimodal pattern of species richness with peaks in the middle reaches of a river. In contrast, on two of three occasions corresponding to major flooding events, we found that the distribution of species richness of naturally occurring vascular plants resembled that of regional diversity: a monotonic decrease from headwater to coast. We also found high floristic similarity between the riparian corridor and the surrounding landscape.Main conclusions  These results suggest that local processes control patterns of riparian species richness, but that species composition is also highly dependent on the regional species pool. We argue that inter‐annual variation in flood disturbance is probably the most important factor producing temporal variability of longitudinal species richness patterns.
Spatial patterns of tree recruitment in a relict population ofPinus uncinata: forest expansion through stratified diffusion
Authors: Julio Camarero J. , Gutiérrez Emilia , Fortin Marie‐Josée , Ribbens Eric 
Published: September 2005

AbstractAim To infer future changes in the distribution of isolated relict tree populations at the limit of a species’ geographical range, a deep understanding of the regeneration niche and the spatial pattern of tree recruitment is needed.Location A relictPinus uncinatapopulation located at the south‐western limit of distribution of the species in the Iberian System of north‐eastern Spain.Methods Pinus uncinataindividuals were mapped within a 50 × 40‐m plot, and their size, age and reproductive status were estimated. Data on seed dispersal were obtained from a seed‐release experiment. The regeneration niche of the species was assessed based on the associations of seedling density with substrate and understorey cover. The spatial pattern of seedlings was described using point‐pattern (Ripley'sK) and surface‐pattern (correlograms, Moran'sI) analyses. Statistical and inverse modelling were used to characterize seedling clustering.Results Pine seedlings appeared aggregated in 6‐m patches. Inverse modelling estimated a longer mean dispersal distance (27 m), which corresponded to the size of a large cluster along the north to north‐eastward direction paralleled by an eastward trend of increasing seedling age. The two spatial scales of recruitment were related to two dispersal processes. The small‐scale clustering of seedlings was due to local seed dispersal in open areas near the edge ofCalluna vulgarismats: the regeneration niche. The long‐range expansion might be caused by less frequent medium‐distance dispersal events due to the dominant north‐westerly winds.Main conclusions To understand future range shifts of marginal tree populations, data on seed dispersal, regeneration niche and spatial pattern of recruitment at local scales should be obtained. The monitoring of understorey communities should be a priority in order to predict correctly shifts in tree species range in response to global warming.
Historical biogeography of Australian Rhamnaceae, tribe Pomaderreae
Authors: Ladiges Pauline Y. , Kellermann Jürgen , Nelson Gareth , Humphries Christopher J. , Udovicic Frank 
Published: September 2005

AbstractAim To discover the pattern of relationships of areas of endemism for Australian genera in the plant family Rhamnaceae tribe Pomaderreae for comparison with other taxa and interpretation of biogeographical history.Location Australian mainland, Tasmania and New Zealand.Methods A molecular phylogeny and geographic distribution of species within four clades of Pomaderreae are used as a basis for recognition of areas of endemism and analysis of area relationships using paralogy‐free subtrees. The taxon phylogeny is the strict consensus tree from a parsimony analysis of 54 taxa, in four clades, and sequence data for the internal transcribed spacer regions of ribosomal DNA (ITS1‐5.8S‐ITS2) and the plastid DNA regiontrnL‐F.Results The biogeographical analysis identified five subtrees, which, after parsimony analysis, resulted in a minimal tree with 100% consistency and seven resolved nodes. Three sets of area relationships were identified: the areas of Arnhem and Kimberley in tropical north Australia are related based on the phylogeny of taxa withinCryptandra; the moister South‐west of Western Australia, its sister area the coastal Geraldton Sandplains, the semi‐arid Interzone region and arid Western Desert are related, based on taxa withinCryptandra,Spyridium,TrymaliumandPomaderris; and the eastern regions of Queensland, McPherson‐Macleay, south‐eastern New South Wales (NSW), Victoria, southern Australia, Tasmania and New Zealand are related based onCryptandra,PomaderrisandSpyridium. Tasmania and NSW are related based entirely onCryptandra, but the position of New Zealand relative to the other south‐eastern Australian regions is unresolved.Main conclusions The method of paralogy‐free subtrees identified a general pattern of geographic area relationships based on Australian Pomaderreae. The widespread distribution of clades, the high level of endemicity and the age of fossils for the family, suggest that the Pomaderreae are an old group among the Australian flora. Their biogeographical history may date to the early Palaeogene with subsequent changes through to the Pleistocene.
Historical biogeography of two alpine butterflies in the Rocky Mountains: broad‐scale concordance and local‐scale discordance
Authors: DeChaine Eric G. , Martin Andrew P. 
Published: September 2005

AbstractAim We inferred the phylogeography of the alpine butterflyColias meadiiEdwards (Pieridae) and compared its genetic structure with that of another high elevation, co‐distributed butterfly,Parnassius smintheusDoubleday (Papilionidae), to test if the two Rocky Mountain butterflies responded similarly to the palaeoclimatic cycles of the Quaternary.Location Specimens were collected from 18 alpine sites in the Rocky Mountains of North America, from southern Colorado to northern Montana.Methods We sequenced 867 and 789 nucleotides of cytochrome oxidase I from an average of 19 and 20 individuals forC. meadiiandP. smintheus, respectively, from each of the same 18 localities. From the sequence data, we calculated measures of genetic diversity within each population (H,θ), genetic divergence among populations (FST), and tested for geographic structure through an analysis of molecular variance (amova). Population estimates were compared against latitude and between species using a variety of statistical tests. Furthermore, nested clade analysis was implemented to infer historic events underlying the geographic distribution of genetic variation in each species. Then, we compared the number of inferred population events between species using a nonparametric Spearman's rank correlation test. Finally, we ran coalescent simulations on each species’ genealogy to test whether the two species of Lepidoptera fit the same model of population divergence.Results Our analyses revealed that: (1) measures of within‐population diversity were not correlated with latitude for either species, (2) within‐site diversity was not correlated between species, (3) within a species, nearly all populations were genetically isolated, (4) both species exhibited significant and nearly identical partitioning of genetic variation at all hierarchical levels of theamova, including a strong break between populations across the Wyoming Basin, (5) both species experienced similar cycles of expansion and contraction, although fewer were inferred forC. meadii, and (6) data from both species fit a model of three refugia diverging during the Pleistocene.Main conclusions While our findings supported a shared response of the two butterfly species to historic climate change across coarse spatial scales, a common pattern was not evident at finer spatial and temporal scales. The shared demographic history of the two species is consistent with an expanding–contracting archipelago model, suggesting that populations persisted across the geographic range throughout the climate cycles, experiencing isolation on ‘sky islands’ during interglacial periods and becoming connected as they migrated down‐slope during cool, wet climates.
Spider diversity in cereal fields: comparing factors at local, landscape and regional scales
Authors: Clough Yann , Kruess Andreas , Kleijn David , Tscharntke Teja 
Published: September 2005

AbstractAim  Factors acting at various scales may affect biodiversity, demanding analyses at multiple spatial scales in order to understand how community richness is determined. Here, we adopted a hierarchical approach to test the contribution of region, landscape heterogeneity, local management (organic vs. conventional) and location within field (edge vs. centre) to the species richness and abundance of spiders in cereals.Location  Three regions of western and central Germany: Leine Bergland, Soester Boerde, and Lahn‐Dill Bergland.Methods  Forty‐two paired organic and conventional winter wheat fields were compared. Field pairs were located in areas ranging from structurally simple to structurally complex landscapes. In May and June 2003, spiders were sampled using pitfall traps. Linear mixed models were used to determine the relationship of spider diversity and abundance with regional spatial factors and landscape heterogeneity within a 500‐m radius, as well as with local management and within‐field location.Results  Within‐field location of the traps and landscape heterogeneity were the best predictors of species richness: more species were found in field edges and in heterogeneous landscapes. Region and local management had no effect on species richness. Activity density was higher in field edges and differed among regions.Main conclusions  The diversity of farmland spiders was influenced by differences at two of the spatial scales (edge vs. centre, simple vs. complex landscapes), but not at the two others (field management, region), emphasizing the importance of analyses at a variety of spatial scales for an adequate explanation of patterns in biodiversity. Our study suggests that promoting heterogeneity in land use at landscape scales is one of the keys to promoting spider diversity in agroecosystems.
Serum uric acid levels and risk for acute ischaemic nonembolic stroke in elderly subjects
Authors: MILIONIS H. J. , KALANTZI K. J. , GOUDEVENOS J. A. , SEFERIADIS K. , MIKHAILIDIS D. P. , ELISAF M. S. 
Published: September 2005

Abstract.Background.  Elevated serum uric acid (SUA) levels have been proposed as an independent risk factor for cardiovascular (CV) morbidity and mortality. Recent evidence suggests that treatments with a hypouricaemic action have a favourable effect on CV event prevention.Objectives.  The association between SUA and acute ischaemic/nonembolic stroke was assessed in a population‐based case–control study in the prefecture of Ioannina, Epirus, Greece.Subjects and methods.  A total of 163 patients aged older than 70 years (88 men and 75 women) admitted due to a first‐ever‐in‐a‐lifetime acute ischaemic/nonembolic stroke and 166 volunteers (87 men and 79 women) without a history of CV disease were included. The association between SUA and stroke was determined by multivariate logistic regression modelling after adjusting for potential confounding factors.Results.  Stroke patients showed higher concentrations of SUA compared with controls (333.1 ± 101.1 μmol L−1 vs. 285.5 ± 83.3 μmol L−1; P < 0.001). In univariate analysis elevated SUA levels were associated with increased risk for ischaemic stroke [odds ratio (OR) 1.42, 95% confidence interval (CI) 1.21–1.64, P < 0.0001]. Compared to patients with SUA levels in the lowest quintile, those within the highest quintile had a 2.8‐time increase in the odds of suffering an ischaemic stroke (OR 2.81, 95% CI 1.67–4.73, P < 0.001). This association was strong even after controlling for gender, age, body mass index, the presence of hypertension and diabetes mellitus, drug treatment and lipids (OR 2.90, 95% CI 1.59–5.30, P = 0.001).Conclusion.  Elevated SUA is associated with an increased risk for acute ischaemic/nonembolic stroke in a strictly defined population of elderly individuals independently of concurrent metabolic derangements. This association may need to be considered when treating the elderly.