bluuebunny/crossref_metadata_2025_split huggingface dataset:
Habitat predicts losses of red grouse to individual hen harriers
Authors: Amar Arjun , Arroyo Beatriz , Redpath Stephen , Thirgood Simon 
Published: April 2004

Summary

Hen harriers Circus cyaneus prey on red grouse Lagopus l. scoticus and high breeding densities of harriers can limit the number of grouse available for shooting in the autumn. Ultimately, grouse hunting contributes to the maintenance of heather moorland, an ecologically important habitat for biodiversity in general and hen harriers in particular. Predation rates vary widely among harrier individuals. Understanding which factors influence this variation would be useful to target management to mitigate the effect of harriers on grouse, such as diversionary feeding.
We used a simple habitat‐based approach to test whether we could identify harrier nests to which most grouse were delivered. Using remote sensing habitat data, we tested whether delivery rates of dead grouse to the nest by hen harriers were higher for those pairs nesting in sites with more heather Calluna vulgaris. A relationship between heather cover and grouse delivery rates might have been expected as grouse densities were correlated with heather cover.
After adjusting for annual variation in grouse abundance, the rate at which grouse were delivered to harrier nests was positively associated with the proportion of heather cover within 2 km of harrier nests. This was primarily due to the positive effect of heather cover on female delivery rates.
This result allowed us to use habitat data to predict the harrier nests to which most grouse chicks would be delivered. Comparison of predictions of the model with observations of food delivery to nests indicated that, in terms of grouse chick delivery, the model correctly predicted the top 50% of harrier nests in five of six years.
We undertook an experiment where carrion was provided to certain harriers at nest sites, in order to decrease their predation on grouse. Data from this experiment showed that when harriers were given diversionary food, the relationship between grouse predation rate and habitat was removed, with grouse predation reduced to negligible levels in most cases. This demonstrated the increased benefit of feeding birds with the highest proportion of heather cover within 2 km of their nest sites, rather than feeding birds at random within the conflict population.
Synthesis and applications. The amount of heather cover around hen harrier nests can be used to predict which pairs will predate most grouse within a population. This information should facilitate targeted management practices, which may accrue greater benefit for grouse stocks and potentially reduce the conflict between grouse shooting and conservation of biodiversity.
Habitat selection by song thrushes in stable and declining farmland populations
Authors: Peach Will J. , Denny Matthew , Cotton Pete A. , Hill Ian F. , Gruar Derek , Barritt David , Impey Andrew , Mallord John 
Published: April 2004

Summary

Losses of farmland birds from the wider countryside have become a major conservation issue in the UK and Europe. Song thrush Turdus philomelos populations in lowland rural Britain declined by approximately 70% during 1970–95, most severely on intensively managed arable farmland. Comparison between a stable population on mixed farmland and a rapidly declining population on arable farmland revealed fewer nesting attempts each summer by birds in the declining population, and annual productivity was insufficient to maintain local population density. Inadequate food resources were the most plausible cause.
We compared breeding season habitat selection (using radio‐telemetry) and earthworm availability (a major component of summer diet) for song thrushes in the same two farmland populations.
Territory settlement in the mixed farmland landscape involved the selection of field boundaries and woodland and the avoidance of arable crops. Field boundaries and gardens were selected in the arable landscape, while arable break crops and small areas of woodland were avoided.
Habitat selection (intensity of usage) did not change through the breeding season and did not differ between study areas. Scrub, woodland edge, wet ditches and bare soil in gardens were preferred foraging habitats, while cereals were avoided.
Habitat utilization (amount of usage) differed markedly between study areas. Woodland and grassland accounted for 53% of all habitat usage in the mixed farmland landscape compared with just 13% in the arable landscape. Gardens and arable crops were more heavily utilized in the arable landscape, accounting for 58% of all usage compared with 22% in the mixed landscape.
Earthworm availability declined markedly between April and June as surface soils dried out. Lower earthworm availability in the arable landscape was associated with more rapid and pronounced drying of surface soils.
Synthesis and applications. Lack of woodland and grassland, and the faster drying of surface soils in the arable landscape, combined to limit the availability to thrushes of key summer invertebrate prey. Loss of hedgerows, scrub and permanent grassland with livestock, and the wide‐scale installation of under‐field drainage systems, have probably all contributed to the decline of song thrushes on UK arable farmland. New agri‐environment measures may be needed to provide the nesting cover adjacent to invertebrate‐rich damp soils that song thrushes require to sustain annual productivity.
Modelling habitat selection and distribution of the critically endangered Jerdon's courser Rhinoptilus bitorquatus in scrub jungle: an application of a new tracking method
Authors: Jeganathan Panchapakesan , Green Rhys E. , Norris Ken , Vogiatzakis Ioannis N. , Bartsch Annett , Wotton Simon R. , Bowden Christopher G. R. , Griffiths Geoffrey H. , Pain Debbie , Rahmani Asad R. 
Published: April 2004

Summary

Jerdon's courser Rhinoptilus bitorquatus is a nocturnally active cursorial bird that is only known to occur in a small area of scrub jungle in Andhra Pradesh, India, and is listed as critically endangered by the IUCN. Information on its habitat requirements is needed urgently to underpin conservation measures. We quantified the habitat features that correlated with the use of different areas of scrub jungle by Jerdon's coursers, and developed a model to map potentially suitable habitat over large areas from satellite imagery and facilitate the design of surveys of Jerdon's courser distribution.
We used 11 arrays of 5‐m long tracking strips consisting of smoothed fine soil to detect the footprints of Jerdon's coursers, and measured tracking rates (tracking events per strip night). We counted the number of bushes and trees, and described other attributes of vegetation and substrate in a 10‐m square plot centred on each strip. We obtained reflectance data from Landsat 7 satellite imagery for the pixel within which each strip lay.
We used logistic regression models to describe the relationship between tracking rate by Jerdon's coursers and characteristics of the habitat around the strips, using ground‐based survey data and satellite imagery.
Jerdon's coursers were most likely to occur where the density of large (> 2 m tall) bushes was in the range 300–700 ha−1 and where the density of smaller bushes was less than 1000 ha−1. This habitat was detectable using satellite imagery.
Synthesis and applications. The occurrence of Jerdon's courser is strongly correlated with the density of bushes and trees, and is in turn affected by grazing with domestic livestock, woodcutting and mechanical clearance of bushes to create pasture, orchards and farmland. It is likely that there is an optimal level of grazing and woodcutting that would maintain or create suitable conditions for the species. Knowledge of the species’ distribution is incomplete and there is considerable pressure from human use of apparently suitable habitats. Hence, distribution mapping is a high conservation priority. A two‐step procedure is proposed, involving the use of ground surveys of bush density to calibrate satellite image‐based mapping of potential habitat. These maps could then be used to select priority areas for Jerdon's courser surveys. The use of tracking strips to study habitat selection and distribution has potential in studies of other scarce and secretive species.
New paradigms for modelling species distributions?
Authors: Rushton S. P. , Ormerod S. J. , Kerby G. 
Published: April 2004

Summary

The management of both desirable and undesirable species requires an understanding of the factors determining their distribution. Quantitative distribution models offer simple methods for formulating the species–habitat link and the means not only for predicting where species should occur, but also for understanding the factors involved. Generalized linear modelling, in particular, links the incidence of species to habitat variables, and has increasingly formed the backbone of the modelling approaches used. New ‘data technologies’, such as remote sensing and geographical information systems, have further broadened these modelling applications to almost any ecological system and any species for which there are distribution data.
Many previous approaches have aimed to identify the most parsimonious model with the best suite of predictors, selected on the basis of null hypothesis testing. However, information‐theoretic approaches based on Akaike's information criterion allow the selection of a best approximating model or a subset of models from a set of candidates. Information‐theoretic approaches require a deeper understanding of the biology of the system modelled and may well become an improved paradigm for species distribution modelling.
Synthesis and applications. This special profile of six papers demonstrates the development in methodology used in species distribution modelling. The papers show how information‐theoretic approaches can be coupled with emerging data technologies to address issues of conservation significance. With conservation biology and applied ecology at the forefront of many of the basic science developments so far, we expect these methods to pervade other areas of ecological research more fully in future.
Conservation genetics of two co‐dominant grass species in an endangered grassland ecosystem
Authors: Gustafson D. J. , Gibson D. J. , Nickrent D. L. 
Published: April 2004

SummaryGlobal habitat fragmentation and loss of undisturbed grasslands has led to the use of non‐local seed and cultivars in restoration. There is concern that these sources may be genetically depauperate and their introduction may lead to loss of unique local genotypes. Within this context we considered the issue with regard to the once widespread but now highly fragmented North American tallgrass prairie.We characterized the genetic diversity and genetic relationships of the co‐dominant species in this system, big bluestemAndropogon gerardiiand Indian grassSorghastrum nutans, from seven remnant and six restored local tallgrass prairies, a non‐local remnant prairie, and five cultivated varieties.Randomly amplified polymorphic DNA (RAPD) analysis of these grasses showed that genetic diversity was mostly retained within rather than among populations, and did not differ among restored or remnant populations or cultivars.Genetic diversity estimates were not correlated with the area of the grassland, nor was there a clear association between diversity and species abundance. All of the restored grasslands in this study were established with seed from at least two local populations and were as genetically diverse as remnant sites.Principal components analysis of RAPD band frequencies showed that the local remnant and restored populations were genetically different from the non‐local remnant grasslands and were consistently different to the cultivars. The genetic relationships among local remnant and restored populations reflected biogeography and human activities.Synthesis and applications.Restoration practitioners have often assumed that small populations are genetically depauperate and therefore the need for multiple seed sources to increase genetic diversity outweighs concerns over potential genetic differences among widespread species. Our research, however, indicates that genetic diversity is much less of an issue in these perennial outcrossing autopolyploid grasses than genetic differences among local and non‐local or cultivar seed sources. Combining these results with our previous research, indicating differences in plant performance as a function of the source population, suggests that genetic differences and ecological performance among local and non‐local seed sources are more of a concern than genetic diversity. Translocating non‐local seed in order to increase diversity, or using cultivars, is likely to alter the genetic structure of remnant populations and potentially influence the associated community and affect ecosystem structure and function in unforeseen ways.
Combining probabilities of occurrence with spatial reserve design
Authors: Cabeza Mar , Araújo Miguel B. , Wilson Robert J. , Thomas Chris D. , Cowley Matthew J. R. , Moilanen Atte 
Published: April 2004

SummaryThere is a great concern about the loss of biodiversity that calls for more nature protection. Unfortunately, the funding available for conservation is limited, and often a compromise is needed between nature protection and economic interests. Reserve selection algorithms are optimization techniques that concentrate on identifying a set of reserves that represents biodiversity efficiently. Simple approaches to reserve selection use presence–absence data assuming that if a species occurs in a selected reserve, it will persist there indefinitely.A refinement of this technique is the selection of reserves according to the local probabilities of occurrence of the given species. These can be estimated from habitat models fitted by empirical modelling techniques. However, local probabilities of occurrence are not static, and are influenced by the changing threats to biodiversity in and around the reserves.The effects of landscape change can be minimized when compact reserves are favoured. Compact reserves that represent all species with a given target probability of occurrence can be achieved by combining the probability approach with spatial reserve design.In this study we brought together two reserve selection approaches that implicitly deal with biodiversity persistence, by combining habitat models and spatial reserve design in a single algorithm. We applied the combined algorithm to a data set of 26 species of butterflies from north Wales.For the particular case study addressed in this paper, clustered reserve networks could be identified at no or a small increase in cost.A new, backwards, heuristic algorithm performed better and more consistently than the regular forwards heuristic approach.Synthesis and applications. The reserve selection approach presented considers habitat quality (via probabilities of occurrence) and the spatial configuration of the reserves during the selection process. Emphasis on reserve networks that include high‐quality sites in an aggregated manner increases the potential for long‐term persistence of species in the reserve network.
The impact of different intensities of regular donor plasmapheresis on humoral and cellular immunity, red cell and iron metabolism, and cardiovascular risk markers
Authors: Tran‐Mi B. , Storch H. , Seidel K. , Schulzki T. , Haubelt H. , Anders C. , Nagel D. , Siegler K. E. , Vogt A. , Seiler D. , Hellstern P. 
Published: April 2004

Background and Objectives  Major studies are still lacking on the impact of differing intensities of long‐term donor plasmapheresis, not only on total serum protein, albumin and immunoglobulin G (IgG), but also on humoral and cellular immunity, red cell and iron metabolism, and biochemical cardiovascular risk markers.Materials and Methods  Three groups of donors, comprising 483 individuals undergoing differing intensities of long‐term serial plasmapheresis, were entered into a cross‐sectional study. A fourth control group consisted of 100 non‐donors. In addition to measuring total protein, albumin and IgG levels, we determined parameters of humoral and cellular immunity, red cell and iron metabolism and recognized biochemical cardiovascular risk factors.Results  The median annual net amount of plasma donated by the three donor groups was 37, 16 and 10 l, respectively (P < 0·0001). Donors had significantly lower total serum protein, albumin and IgG levels than non‐donors (P < 0·0001), but the intensity of plasmapheresis had no influence on those parameters. Like non‐donors, all plasma donors had normal humoral and cellular immunity. No increased rates of iron store depletion were observed in the three groups of plasma donors. Plasma donors were not at increased cardiovascular risk.Conclusions  Regular donor plasmapheresis of up to 45 l of plasma per year appears to be as safe as more moderate plasmapheresis programmes, with respect to the parameters analysed in this study. Individuals donating under these conditions did not develop impaired humoral and cellular immunity, iron store depletion, or increased cardiovascular risk with regard to established biochemical risk markers. Prospective studies are required to determine more exactly than in retrospective analyses the reasons why donors withdraw from plasmapheresis programmes.
Productivity and canopy modification of Medicago arborea as affected by defoliation management and genotype in a Mediterranean environment
Authors: Amato G. , Stringi L. , Giambalvo D. 
Published: April 2004

Abstract Medicago arborea is one of the most potentially valuable fodder shrubs in a Mediterranean environment because of its high preference by small ruminants and its nutritive value. Edible biomass production is affected by agronomic and environmental factors. A study, carried out in an inland area of Sicily in the growing seasons of 1994/95, 1995/96 and 1996/97, evaluated the forage production and canopy modification in a M. arborea plantation after (i) commencing defoliation 1 or 2 years after transplanting and (ii) defoliating only in autumn (A), only in early summer (S) or in both seasons (A and S). Six clones derived from five different Mediterranean populations were used. Plant age at the first defoliation did not significantly influence forage production. The genotypes differed in growth rate and forage production. The season and frequency of defoliation markedly influenced forage production and canopy size. The highest annual production was obtained by defoliating once a year in early summer (on average, 1·65, 2·85 and 4·50 tonnes ha−1 respectively in the three growing seasons). With the A and S, and A defoliation treatments, production decreased over 3 years by, on average, 0·19 and 0·57 respectively, but the differences became more marked over a 3‐year period. Defoliating only in early summer, however, resulted in an excessive shrub height (>120 cm, 3 years after transplanting), thereby increasing problems of accessibility to small grazing ruminants, and possibly necessitating cutting. On the contrary, the A and S defoliation made it possible to limit the height to <90 cm.
Nitrogen recovery and loss in a fertilized elephant grass pasture
Authors: Martha G. B. , Corsi M. , Trivelin P. C. O. , Alves M. C. 
Published: April 2004

AbstractLimited information is available regarding the recovery and loss of fertilizer nitrogen (N) applied to intensively managed tropical grass pastures. An experiment was carried out in Brazil to determine the fertilizer‐N recovery and ammonia volatilization loss in an elephant grass (Pennisetum purpureum, Schum.) pasture fertilized with 100 kg N ha−1 as urea or ammonium sulphate, labelled with 15N, in late summer (LS) or in mid‐autumn (MA). Herbage mass was highest and litter mass was lowest in LS (P < 0·05). The N concentration of herbage was highest in autumn (P < 0·05) and the total N content in soil was lower in LS than in MA (P < 0·05), reflecting the high N uptake capacity of the grass. Proportionately higher 15N recovery in litter mass (P < 0·05) was observed in autumn (0·094) than in LS (0·0397) and the 15N recovery in herbage was 0·046 higher for ammonium sulphate‐fertilized pastures (P < 0·05; proportionately 0·243 for ammonium sulphate and 0·197 for urea). Around 0·60 of the fertilizer‐15N recovered was retained in soil and in non‐harvestable fractions of the plant. The NH3 volatilization loss was higher in LS and most of the N loss occurred soon after fertilizer application. Urea and ammonium sulphate fertilizers were equally effective in sustaining herbage dry matter yield in the short term. However, the use of ammonium sulphate, rather than urea, would be preferable for LS applications when the objective is to reduce NH3 volatilization losses.
Seborrheic keratoses: A study comparing the standard cryosurgery with topical calcipotriene, topical tazarotene, and topical imiquimod
Authors: Herron Mark D. , Bowen Anneli R. , Krueger Gerald G. 
Published: April 2004

AbstractBackground  Patients with seborrheic keratoses frequently desire an effective topical therapy for seborrheic keratoses.Objective  To compare topical calcipotriene, topical tazarotene, and topical imiquimod with standard cryosurgery in the treatment of seborrheic keratoses.Methods  Fifteen patients with numerous seborrheic keratoses were enrolled in an open‐label study comparing cryosurgery with topical agents. Eight separate seborrheic keratoses were selected to be treated with topical medications. One lesion was treated with cryosurgery.Results  One treatment with cryosurgery led to clinical and histological improvement of all lesions treated. Neither scarring nor recurrence resulted in cryosurgery. In seven of 15 patients, tazarotene 0.1% cream applied BID caused clinical improvement in lesions within 16 weeks.Conclusion  Cryosurgery produces clinical and histological improvement of seborrheic keratoses. The result with cryosurgery was cosmetically acceptable to all patients. Responders to tazarotene cream 0.1% found it cosmetically acceptable.
Superficial malignant fibrous histiocytoma presenting as recurrent atypical fibroxanthoma
Authors: Ly Hoang , Selva Dinesh , James Craig L , Huilgol Shyamala C 
Published: April 2004

SUMMARYAtypical fibroxanthoma (AFX) and malignant fibrous histiocytoma (MFH) are neoplasms of probable fibrohistiocytic lineage. The precise relationship between AFX and MFH remains controversial. We present two cases in which a lesion was excised from the face of an elderly person and reported as AFX. Both cases recurred within 12 months and were reclassified as MFH. They were excised with slow Mohs' micrographic surgery, with adjuvant radiotherapy in one case. In the other, a further recurrence was treated with orbital exenteration and radiotherapy. We review the difficulties in differentiating between AFX and MFH and the implications for treatment.
Paraneoplastic pityriasis rubra pilaris in association with bronchogenic carcinoma
Authors: Kurzydlo Ann‐Maree , Gillespie Rod 
Published: April 2004

SUMMARYPityriasis rubra pilaris (PRP) is an uncommon dermatosis occasionally reported in association with an underlying malignancy. We report a 61‐year‐old woman in whom PRP preceded the diagnosis of bronchogenic carcinoma by approximately 11 months. The clinical picture in this case included atypical cutaneous signs and mucous membrane involvement. Curative treatment of the malignancy with radiotherapy led to resolution of the mucocutaneous changes within months. A presentation of PRP, particularly if atypical, or in an older patient, should prompt consideration of an associated internal malignancy.