bluuebunny/crossref_metadata_2025_split huggingface dataset:
Editors' Introduction: Birds and Agriculture
Authors: Ormerod S.J. , Watkinson A.R. 
Published: March 2003

1. Around 10% of recent papers in the Journal of Applied Ecology have examined interactions between birds and agriculture. This statistic reveals the important role now played by ecologists in assessing the effects of agricultural development worldwide. It also reflects the position of birds as both indicators and targets of agricultural change: their patterns of behaviour, distribution, seasonal phenology and demography track closely onto the spatial and temporal scales of agricultural intensification. 2. Papers in this Special Profile illustrate how research in this sphere has shifted towards assessing the processes by which birds are affected ecologically by agricultural change. The works examine spatial patterns in extinction; assess long‐term trends in bird abundance and agricultural practice; reveal how foraging and breeding performance in farmland birds varies between habitats; and evaluate the role of large‐scale modelling in examining hypotheses about the influences of land management on birds. The final paper shows that birds can have intrinsically positive value in agricultural systems. 3. All the papers propose management prescriptions for agricultural areas that blend the microscopic – for example, how to modify local land structure to benefit birds – and the macroscopic – for example, by suggested inputs into land‐use policy. Perhaps most pertinent is the key conclusion that agricultural change is multivariate, so that straightforward univariate effects on birds are unlikely. Restoration of impacted populations might therefore require holistic strategies that encourage appropriately scaled agricultural extensification. Success would be most likely if farmers, conservationists and other key players were engaged collaboratively in the process. 4. Current ideas about restoring farmland bird populations share a common assumption: if agricultural practice has reduced populations hitherto, then agricultural practice can restore the losses. We suggest that this assumption carries a range of predictions that now require testing through sustainable farm management – a situation ideally suited to ‘BACI’ style experiments. 5. We reiterate the need to expand work on other groups of organisms affected negatively or positively by agricultural management to allow a broader perspective of impacts or benefits.
Habitat use and diet of skylarks Alauda arvensis wintering on lowland farmland in southern Britain
Authors: Donald P.F. , Buckingham D.L. , Moorcroft D. , Muirhead L.B. , Evans A.D. , Kirby W.B. 
Published: March 2003

Summary

The habitat use and diet of skylarks wintering on lowland farms were studied to assess whether changes in agricultural practice could have reduced their most favoured wintering habitats or foods. Faecal samples were collected and soil seed densities were estimated. Skylarks in 122 cereal stubble fields in Oxfordshire were counted monthly to examine habitat use.
Cereal stubble fields were more likely to be occupied than other crops, and densities of birds in occupied fields were high. Barley stubbles were significantly more likely to be occupied than wheat stubbles. Growing cereals were weakly selected. Sugar beet stubbles held high densities of birds. Rotational set‐aside was occupied more frequently and held higher densities than non‐rotational set‐aside.
Field size affected field occupancy independently of crop type, with larger fields more likely to be occupied. Fields enclosed by hedges or trees tended to be avoided. Cereal and set‐aside fields that were occupied by skylarks in at least 1 month held significantly higher soil seed densities than fields that were not occupied.
Differences in occupancy between crops could be explained by diet. Birds in cereal stubbles fed largely on cereal grain, whereas those in winter cereals fed largely on cereal leaves. Broad‐leaved weed leaves were strongly selected as food in cereal crops and farmland grass fields. In grass fields, the proportion of the diet made up by broad‐leaved weeds was positively correlated with their availability. Broad‐leaved weed seeds did not make up a significant dietary component in any crop.
Our results show that the shift from spring to autumn sowing of cereals has led to a loss of the skylark’s most strongly selected wintering habitat and best food source. In winter cereals and in grass there was a high selectivity for relatively scarce, and probably declining, food resources. Our results suggest that the retention of weed‐rich cereal (particularly barley) and sugar beet stubbles through the winter, particularly in large open blocks, will improve conditions for skylarks in winter. Whole‐field rotational set‐aside, particularly as naturally regenerating cereal stubbles, provides good winter food resources for skylarks.
Particle selection by snail hosts of human schistosomes in relation to their survival strategies and possible control by ‘environmental antibodies’
Authors: Thomas J.D. 
Published: March 2003

SummaryExperiments were undertaken withBiomphalaria glabratato (i) elucidate the mechanisms used for selecting, regulating and utilizing sand particles and (ii) evaluate particulate controlled‐release formulations (CRF), or ‘environmental antibodies’, to control target snails.The snails selected sand particles by size, mass and density. The numbers and mass of sand particles in the guts increased with snail size, and fed snails had significantly more sand particles in their guts than deprived snails.Snails benefited from ingesting sand particles. Increasing the weights of 63–125‐µm sand particles from 8·5 mg to 150–170 mg resulted in progressive, significant, increases in the numbers of sand particles in the various gut compartments and also enhanced snail growth.Snails did not discriminate between sand and glass particles of the same size. When offered unwashed acidic sand there was a lag of 5–6 h before ingestion, but this could be reduced by preconditioning in media rich in base cations or chemical factors of snail origin. Under equilibrium conditions ingested sand constituted approximately 2·5% of the total snail weight but this amount was exceeded when snails were presented with large quantities of sand.The parts of the gut involved in sorting and regulating the turnover of sand particles and food were described. The gizzard, caecal and digestive gland strings traversed the gut as far as the rectum in approximately 2·8 h, 6–8 h and 8 h, respectively.Coprophagy by the snails facilitated the recycling of sand and its retention in the gut.Optimally sized, 63–250‐µm, protein microcapsules containing butanoate and maltose were ingested by snails in significantly greater amounts than untreated control microcapsules. The addition of copper caused the capsules to become repellent.These results will advance the design of effective, ecologically acceptable, environmental antibodies in the form of controlled‐release microcapsules to control schistosome snails. This work illustrates how a combination of detailed study of snail anatomy, feeding experiments and ecological understanding can contribute to the control of the intermediate hosts of a major human parasite.
The influence of management regime and altitude on the population structure of Succisapratensis: implications for vegetation monitoring
Authors: Bühler Christoph , Schmid Bernhard 
Published: March 2003

Summary

Environmental change and land use may alter the vegetation typical of wetland habitats. However, commonly used techniques for vegetation monitoring that are based on species composition are often not suitable to detect gradual changes in the structure of vegetation at an early stage. In this study we tested if this methodical deficiency could be overcome by observation of the stage structure of a perennial target species.
We studied the density and frequency distribution of four phenological stages of the perennial plant Succisapratensis in 24 calcareous fens in eastern Switzerland. These fens differed in management type (mowing, cattle‐grazing) and altitude (low, medium, high). Among grazed fens, the intensity of management was quantified by direct observation. Species composition and canopy structure of the plant community surrounding S. pratensis were also measured.
High altitude had a positive effect on the density of adult plants of S. pratensis only in mown fens, whereas in grazed fens adult density was highest at medium altitude.
Local densities of seedlings and vegetative adults within a fen were higher in mown than in grazed fens, and lower in fens of the lowest altitude level than of the two higher ones. However, there were no differences in the relative proportions of all four phenological stages among main factors except that significantly fewer seedlings occurred in fens of the lowest altitude level.
It is the intensity rather than the mere type of management regime that is crucial for shaping populations of S. pratensis: for grazed fens, there is a negative relationship between intensity of grazing and density of adult plants of S. pratensis. Moreover, the number, the relative proportion of seedlings and the seed‐set are all negatively correlated with grazing intensity.
The species composition of the plant community, but not its physical structure, was significantly related to the relative proportion of seedlings of S. pratensis, which supports the indicator qualities of the target species.
Monitoring the population structure of one or several target species provides important indicator information about the stability of a whole plant community. For the target‐species approach we propose to use characteristic but frequently and steadily occurring species instead of rare or endangered ones.
The impact of the timing of brush management on the nutritional value of woody browse for mooseAlcesalces
Authors: Rea Roy V. , Gillingham Michael P. 
Published: March 2003

Summary We examined how the removal of above‐ground biomass (mechanical brushing) at different times of the year affected the nutritional value of regenerating shoots of Scouler’s willowSalix scoulerianafor moose for two winters after brushing. Brushing trials were conducted throughout the 1996 and 1997 growing seasons in central British Columbia on a 10‐year‐old regenerating clear‐cut replanted in lodgepole pinePinus contortavar.latifolia. We assessed the nutritional value of the browse in relation to length, diameter, mass, digestible energy, digestible protein, tannin and lignin content of current annual growth shoots in winter, as well as the phenology of plant leafing. One winter after brushing, willows brushed in early July had shoots that were lower in lignin, higher in digestible protein and lower or not different in tannin content compared with shoots from earlier brushed or unbrushed willows. Willows brushed in early July also had long, heavy, shoots that were high in digestible energy and delayed leaf senescence. In the second winter after brushing, willows that were brushed in July had larger shoots that were lower in digestible energy, digestible protein, tannin and lignin content and delayed leaf senescence compared with several other treatments. Willows brushed after July regenerated negligible shoot material in the first year after brushing. Willows brushed in September delayed leaf flush in the first post‐brushing spring. To increase the nutritional value of woody browse for cervids, we suggest that brushing should be performed in early to mid‐July (mid‐summer). Reductions in browse quality and quantity may negatively affect many mammalian species. Therefore, we recommend that the needs of other fauna potentially affected by changes in shrub architecture, shoot morphology and shoot chemistry be considered when planning the timing of brush management activities.
An evaluation of three quick methods commonly used to assess sward height in ecology
Authors: Stewart K.E.J. , Bourn N.A.D. , Thomas J.A. 
Published: March 2003

Summary

Many ecological studies and applications involve measuring the height of grassland swards. An evaluation was made of the practicality, accuracy and comparability of using the sward stick, drop disc and direct methods of measurement. Each method proved to be appropriate for measuring swards that contain a wide range of heights, each was quick to perform, and recorder effects were negligible. Yet each had strengths and weaknesses.
The sward stick gave the most variable results: it was considered the best method for recording the architecture of the sward surface, and hence invertebrate niches, but was poor for measuring short turf. The drop disc was the worst method for recording microheterogeneity in sward architecture and was completely unsuitable for measuring variation in short turf. But in medium‐tall swards, it was considered to be the best method for measuring productivity, vertebrate herbivory and for large‐scale monitoring of land managed for conservation and under agri‐environment schemes. The direct method gave the most consistent and accurate results compared with an independent parameter, soil temperature. It was the only method suitable for measuring variation in short turf.
A serious problem exists when research results, recommendations and assays involve measurements made by more than one method. The sward stick consistently gave higher absolute values than either of the other methods and, apart from in short turf (for which it is unsuitable), the drop disc gave values that were 73% and up to 40% lower, respectively, than those obtained using the sward stick and direct methods. This can lead to major misapplications of ecological results and recommendations in conservation and agri‐environmental projects.
The distribution and colony size of barn swallows in relation to agricultural land use
Authors: Ambrosini Roberto , Bolzern Anna Maria , Canova Luca , Arieni Silvia , Møller Anders Pape , Saino Nicola 
Published: March 2003

Summary The barn swallowHirundo rusticais a semi‐colonial passerine that has declined in some parts of its European range, perhaps as a result of agricultural change. So far, however, swallow breeding populations have been analysed mostly in north‐western Europe. We studied their distribution, abundance, foraging habitat and breeding performance on 125 farms in Italy in relation to current and past livestock farming and agricultural practice. Swallows foraged within 400 m of the farms on which they bred and had a preference for feeding over hayfields. In logistic and multiple regression models, cross‐validated on independent locations, the presence of cattle or pigs in the period 2–5 years beforehand best predicted swallow presence on a farm and, in combination with the presence of stables with traditional architecture, explained 40% of the variance in colony size. Breeding occurred later on farms with no cattle, and fledging success declined with the number of cattle per farm. This study provides the first evidence from central and southern Europe that livestock farming and the architecture of rural buildings affects the distribution and abundance of barn swallows. The data also show how historical ecological information may play an important role in determining current influences on the distribution and abundance of a breeding bird. By augmenting perspectives on swallows at a European scale, our results have important implications for the management and conservation of their breeding populations and allow inferences about the effect of agriculture on future demographic trends.
Control of parasite burdens in wild red grouse Lagopus lagopus scoticus through the indirect application of anthelmintics
Authors: Newborn D. , Foster R. 
Published: March 2003

Summary

Red grouse Lagopus lagopus scoticus populations in Britain exhibit cyclic fluctuations in abundance with periodic population crashes. Substantial evidence exists to suppose that parasitic worms are the major factor causing these population crashes.
This experimental study was undertaken between 1996 and 2000 on two areas of moorland in the north Pennines, UK, to evaluate the efficacy of the indirect application of anthelmintic drugs in the control of the caecal nematode Trichostrongylus tenuis.
On one area, grouse were given access to anthelmintic drugs incorporated into grit (medicated grit) to control T. tenuis numbers, while on the second control area the birds had access to grit without anthelmintic drugs incorporated (plain grit). In the winter of 1998–99 the treatment was reversed between the two areas.
Adult grouse from the experimentally treated area had significantly lower infections of T. tenuis than grouse from the control area. Hen grouse, which had access to anthelmintic drugs, did not produce significantly more eggs or have a greater hatching success than hens with access only to plain grit. Chick survival was significantly greater on the medicated grit areas, with a significant difference in breeding success. Hens that had access to anthelmintic drugs reared more than twice as many chicks as control hens.
No significant difference was found in red grouse survival between grit treatments.
The increase in grouse numbers arising from the use of medicated grit enhances the viability of red grouse shooting because the cost of treatment appears to be low relative to the return from an increased harvest.
SERCA function declines with age in adrenergic nerves from the superior cervical ganglion
Authors: Pottorf W. J. , Duckles S. P. , Buchholz J. N. 
Published: March 2003

1 Intracellular calcium is a universal second messenger integrating numerous cellular pathways. An age‐related breakdown in the mechanisms controlling [Ca2+]i homeostasis could contribute to neuronal degeneration. One component of neuronal calcium regulation believed to decline with age is the function of sarco/endoplasmic reticulum calcium ATPase (SERCA) pumps. 2 Therefore we investigated the impact of age on the capacity of SERCA pumps to control high (68 m
M) [K+]‐evoked [Ca2+]i‐transients in acutely dissociated superior cervical ganglion (SCG) cells from 6‐ and 20‐month‐old Fisher‐344 rats. Calcium transients were measured by fura‐2 microfluorometry in the presence of vanadate (0.1 μM) to selectively block plasma membrane calcium ATPase (PMCA) pumps, dinitrophenol (100 μM) to block mitochondrial calcium uptake and extracellular sodium replaced with tetraethylammonium to block Na+/Ca2+‐exchanger, thus forcing the neuronal cells to rely on SERCA uptake to control [Ca2+]i homeostasis. 3 In the presence of these calcium buffering blockers, the rate of recovery of [Ca2+]i was significantly slower and time to recover to approximately 90% of resting [Ca2+]i was significantly greater in SCG cells from old (20 months) compared with young (6 months) animals. 4 This age‐related change in the recovery phase of [K+]‐evoked [Ca2+]i‐transients could not be explained by differences in the sensitivity of SCG cells to the calcium buffering blockers, as no age‐related difference in basal [Ca2+]i was observed. 5 These studies illustrate that when rat SCG cells are forced to rely on SERCAs to buffer [K+]‐evoked [Ca2+]i‐transients, an age‐related decline in SERCA function is revealed. Such age‐related declines in calcium regulation coupled with neuronal sensitivity to calcium overload underscore the importance of understanding the components of [Ca2+]i homeostasis and the functional compensation that may occur with advancing age.
Long‐term effects of daily grazing orbits on nutrient availability in Sahelian West Africa: I. Gradients in the chemical composition of rangeland soils and vegetation
Authors: Turner Matthew D. 
Published: March 2003

Abstract. An investigation of the long‐term effects of livestock grazing on the spatial distribution of plant nutrients was conducted in the Sahelian region of West Africa. The study area was located along the transhumance corridor used for at least the past century by a long‐established population of agropastoralists in central Mali. Spatial variation of plant and soil chemistry across eighteen sites was investigated with respect to a grid, whose axes are defined by distance from a pan from which livestock disperse to graze primarily during the early dry season (D1) and by distance from the nearest of three pans used primarily during the rainy season (D2). Particle size distribution, pH, total C, N, and P of surface soil (0–10 cm) was determined for four composite samples collected at eleven of the eighteen ecological sites. Elemental analysis (N, P, Ca, Mg, K, Mn, Fe, Zn, Cu) was performed on above‐ground tissue samples (excluding seeds) of the three most common grasses and the most common legume collected at all eighteen sites at the end of the rainy season.Results demonstrate that long‐term grazing movements can, over the long‐term, affect nutrient availability over wider spatial scales (5 km radii) than previously observed by shorter‐term studies. Soil and plant chemistry were found in general to be most affected by the historic gradient of cattle presence during the rainy season (D2). Controlling for soil C and coarse sand fraction, soil pH was found to decline with D2 (−0.5 pH units per km D2) and to a lesser extent D1 (−0.15pH units per km D1), a finding that cannot be explained solely by a consideration of local geomorphology. The pH gradient was found to significantly affect micronutrient concentrations in plant tissues. Phosphorus (P) concentrations of plant tissue were found to decrease with D2. The increase in P‐availability near rainy‐season encampments could result from P‐release from Al‐complexes at higher pH and/or by the redistribution of P from outlying zones towards rainy‐season encampments.
A vegetation map of Central Africa derived from satellite imagery
Authors: Mayaux Philippe , Richards Tim , Janodet Eve 
Published: March 2003

Summary Aim This paper presents the Joint Research Centre's TREES Project satellite derived Vegetation Map of Central Africa, at 1:5,000,000 scale, with a detailed description of the vegetation classes and their distribution. The information content of the map is compared with other conventional and satellite derived maps of the region for validation and evaluation purposes. Location The map focuses on the Guineo‐Congolian ecological domain and covers the following countries: Cameroon, Central African Republic, Republic of Congo, Equatorial Guinea, Gabon and the Democratic Republic of Congo. Methods Using coarse resolution satellite imagery a map of vegetation cover has been produced based upon the spectral response of the vegetation cover. Digital image processing and geographical information systems techniques were employed, together with local knowledge, high resolution imagery and expert consultation, to compile a cartographic map product. Results The TREES Vegetation Map of Central Africa has been shown to be strongly correlated with the FAO Forest Resources Assessment for 1990. Comparison with other map sources indicates that the map contains greater spatial detail and is more consistent than conventionally compiled maps. The conventional maps however, contain more thematic information content relating to vegetation type. Main conclusions The map improves our state of knowledge of the vegetation cover of Central Africa and presents the most consistent and spatially detailed view yet published at this scale. Thematic information content on forest type is limited but should be improved in the near future with the inclusion of data from new satellite sensors. This first version of the map and future planned updates should provide an important input for regional stratification and planning purposes for forest resources, biodiversity and climate studies.