bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determinants of survival for the northern brown bandicoot under a landscape‐scale fire experiment
Authors: Pardon L. Guy , Brook Barry W. , Griffiths Anthony D. , Braithwaite Richard W. 
Published: March 2003

Summary

More than half of all Australian bandicoot species (family Peramelidae) are listed by the IUCN as extinct or threatened and changed fire regimes in arid and semi‐arid Australia have been identified as an important agent in their decline. The northern brown bandicoot is currently one of Australia's most common bandicoots, but their continued persistence in the tropical savannas cannot be taken for granted. Previous studies in Kakadu National Park, Northern Territory have shown this species to be prone to sudden declines in abundance, possibly linked to the occurrence of intense fires.
Here we examine the impact of four experimental fire management regimes (fire prevention, early dry season burning, late dry season burning and progressive burning several times through the dry season) on survival of the northern brown bandicoot. The analysis is based on capture–mark–recapture data obtained during a landscape‐scale fire experiment conducted at Kapalga, in Kakadu National Park from 1989 to 1995.
All experimental fire treatments (including total fire exclusion) were associated with decline in survival rates over time, indicating that none of the tested approaches were appropriate for this species. Burning in the late dry season or progressively throughout the dry season produced substantially more severe declines in survival than did early dry season fires or fire exclusion.
Fire regime was found to be the most important determinant of bandicoot survival, far exceeding other factors such as gender, age, vegetation type, rainfall and season, all of which had comparatively little influence. The results demonstrate the importance of the frequency and seasonal timing of fires in determining the survival of bandicoots and suggest that spatially uniform and temporally invariant fire regimes are inappropriate for bandicoot conservation in the north Australian savannas.
Responses of Salsola kali and Panicum virgatum to mycorrhizal fungi, phosphorus and soil organic matter: implications for reclamation
Authors: Johnson N.C. 
Published: March 2003

1.  Owing to the difficulty of finding terrestrial ecosystems without mycorrhizas, their influence on plant community dynamics is not easy to discern. This study utilized unreclaimed taconite mine tailings as a mycorrhiza‐free ecosystem to gain insights about the influence of arbuscular mycorrhizas and soil organic matter on the growth of Salsola kali (an early successional colonist of taconite tailings) and Panicum virgatum (a late successional grass planted during reclamation). 2.  To assess relative mycorrhizal responsiveness, Panicum and Salsola were grown in taconite tailings along an experimental phosphorus gradient with and without mycorrhizal fungal inoculum isolated from reclaimed taconite tailings. At low phosphorus concentrations, mycorrhizal inoculum enhanced the growth (height and dry mass) of Panicum, but it decreased growth at the two highest phosphorous concentrations. At no phosphorus level did mycorrhizal inoculum enhance the growth of Salsola but it decreased growth at the highest phosphorus concentrations. 3.  In field plots, mycorrhizal inoculum and organic soil amendment (compostedpapermill sludge) enhanced the growth of Panicum and decreased the growth of Salsola. 4.  In this experiment, mycorrhizal inoculum enhanced the growth of the late successional grass but, during reclamation operations, manipulating edaphic conditions to favour mycotrophy may be more cost‐effective than large‐scale inoculation. The results of this study suggest that mycotrophy is favoured by increasing soil organic matter and avoiding heavy fertilization.
Germination and emergence characteristics of triazine‐susceptible and triazine‐resistant biotypes of Solanum nigrum
Authors: Kremer E. , Lotz L.A.P. 
Published: March 2003

1.  Seedling emergence patterns of triazine‐susceptible and triazine‐resistant Solanum nigrum in the field were studied in Wageningen, the Netherlands. Emergence patterns were similar in the first year, but in the second year resistant seedlings emerged faster and the number of resistant seedlings was higher. To explain emergence patterns, a germination experiment was carried out. 2.  Seeds from two populations with triazine‐susceptible and ‐resistant biotypes were buried in late autumn and exhumed monthly during spring. Germination was assessed in incubators at different constant temperatures. 3.  The lowest temperatures for germination of seeds from the Achterberg population ranged from 20°C on 1 February to 10°C on 1 May for the susceptible biotype, and from 15°C on 1 February to 10°C on 1 May for the resistant biotype. The lowest temperatures for germination of seeds from the Zelhem population ranged from 25°C on 1 February to 10°C on 1 May for the susceptible biotype, and from 15°C on 1 February to 10°C on 1 May for the resistant biotype. The minimum germination temperature of seeds from the resistant biotype appeared to be lower than that of the susceptible biotype. 4.  Emergence patterns in the field could be explained by soil temperature and different minimum germination temperature requirements of seeds from the triazine‐susceptible and ‐resistant biotype. This knowledge can be used to manage triazine‐resistant biotypes of S. nigrum by the timing of soil cultivation.
Environmental impact prediction using neural network modelling. An example in wildlife damage
Authors: Spitz François , Lek Sovan 
Published: March 2003

1. Decision making in management of environmental impact confronts the problem of analysing relationships in highly complex ecological systems. These relationships are generally non‐linear, and conventional techniques do not apply satisfactorily. The problem is equivalent to that of predicting the output of a black box. Artificial neural networks (ANN) have shown tremendous promise in modelling such situations. 2. The present work describes the development and validation of an ANN in modelling wildlife damage to farmland, a particular instance of ecological impact. An ANN approach was developed and tested using data from 200 damaged plots, and a control sample of 20 undamaged plots, described by 17 environmental characters. The dependent variable was the financial cost of impact per plot. 3. The predictive quality of the ANN models was evaluated through the ‘leave‐one‐out’ procedure. For 82% of predicted values, deviation from observed values is lower than 1780, that is 10% of the range of the observed values. The frequency of bad predictions depends on the minimum level of impact (critical effect size) considered. In France, compensation is given starting from a minimum level of 200 FF. At this level, the frequency of occurrence of Type I errors (predicted impact does not occur) is 7·11%. Different strategies of prevention of impact, using different threshold values for prevention, are analysed. Frequency of Type I errors increases, and that of Type II errors (occurrence of unpredicted impact) decreases as the threshold for prevention increases. 4. Sensitivity analysis allows the determination of the effect of seven quantitative variables on the cost of damage compensation. Proximity of a paved road, proximity and number of houses, and number of other buildings contribute negatively, and three other variables (proportion of the perimeter of the plot occupied by woody vegetation, density of the vegetation, and density of wild boar in the surrounding area) contribute positively to the predicted value. 5. Results show that the utility of impact prediction for prevention depends on the cost of errors and the absolute cost of prevention. 6. Finally, ANNs proved able to learn complex relationships between environmental variables and impact assessment, and to produce operationally relevant predictions. Good predictions can help managers to distribute efficiently their actions between prevention, protection and compensation.
The effects of controlled sheep grazing on the dynamics of upland Agrostis–Festuca grassland
Authors: Hulme P.D. , Pakeman R.J. , Torvell L. , Fisher J.M. , Gordon I.J. 
Published: March 2003

Summary 1. Agrostis capillaris–Festuca ovina‐dominated communities are widespread in the uplands of Great Britain. They are agriculturally productive but little is known about how to manage this community for specific goals. Vegetation trajectories were examined in this plant community under different sheep grazing management regimes at two sites in Scotland. One site had a substantial presence of moorland species, the other was characterized by a more productive vegetation. Management consisted of maintaining sward heights of 3, 4·5 or 6 cm during the growing season, or complete exclusion of grazing stock. 2. Changes in species composition were small over the 7 years of the experiment. Few species invaded or were lost during the course of the study. The observed changes were largely as a result of shifts in abundance of the dominant species. 3. Maintenance of sward height at low levels (3 or 4·5 cm) during the growing season resulted in the spread of Nardus stricta where present. Where N. stricta was absent, the sward developed a higher content of mosses, specifically Hypnum jutlandicum and Rhytidiadelphus squarrosus. 4. Removal of grazing resulted in an increase of cover of grazing‐intolerant species, such as Deschampsia flexuosa and Molinia caerulea, and in the cover of dwarf shrub species where present. 5. The two sites differed in the treatment that resulted in the smallest change in species composition. At the more productive site, maintenance of the sward at 4·5 cm resulted in the smallest overall change in species composition. At the less productive site, grazing the sward to 6 cm resulted in the smallest shift in vegetation composition. Grazing at this height appeared to prevent the spread of both M. caerulea and N. stricta. 6. The study demonstrates that sustainable grazing regimes for upland Agrostis–Festuca grasslands need to take into account both the initial composition of the vegetation, specifically the presence of species capable of replacing A. capillaris and F. ovina and of achieving dominance, and the overall productivity of the site.
Changes in the abundance of farmland birds in relation to the timing of agricultural intensification in England and Wales
Authors: Chamberlain D.E. , Fuller R.J. , Bunce R.G.H. , Duckworth J.C. , Shrubb M. 
Published: March 2003

1. Over the past three decades changes in agricultural management have resulted in increased crop and grass production. This intensification has been accompanied by population declines among farmland bird species and a decline in farmland biodiversity. We have analysed trends in agricultural management in order to quantify the degree of intensification, and have considered how they match change in the farmland bird community. 2. Changes in agriculture through time (1962–95) were examined quantitatively for 31 variables representing crop areas, livestock numbers, fertilizer application, grass production and pesticide use. The majority were highly intercorrelated because factors facilitating intensification simultaneously affected many management activities. 3. Change in agriculture was measured using detrended correspondence analysis (DCA). The period 1970–88 saw most intensification, characterized by increases in the area of oilseed rape, autumn‐sown cereals, and the use of pesticides and inorganic fertilizers. Spring‐sown cereals, bare fallow and root crops declined. 4. Indices of relative population change between 1962 and 1996 were determined for 29 bird species using data from Common Birds Census (CBC) plots on farmland in England and Wales. Principal components analysis (PCA) described a gradient from species that had declined most to those that had increased. 5. The ordinations of agricultural change and bird population change were broadly matching but with a time lag in the response of birds. The most accurately measured agricultural variables for the period 1974–91 matched the changes in farmland birds more closely. 6. We conclude that large shifts in agricultural management are a plausible explanation for the declines in farmland bird populations. We propose a threshold model relating to critical amounts of high‐quality habitat or food resources that may be relevant in explaining the lag in response of birds, and propose it should be taken into account in predicting the effects of future agri‐environment schemes. Identifying individual factors responsible for bird declines is not possible without detailed experimental work because many components of intensification are interdependent. Birds may be responding to a suite of interacting factors rather individual aspects of farm management. Holistic conservation strategy that encourages general extensification of farming practices will be most likely to benefit farmland bird communities.
Effects of late summer cattle grazing on the diversity of riparian pasture vegetation in an upland conifer forest
Authors: Humphrey J.W. , Patterson G.S. 
Published: March 2003

Summary 1.  Species‐rich grassland is important for biodiversity in upland forests, particularly within riparian zones. Prior to afforestation, the botanical diversity of these grasslands was maintained by domestic stock grazing, but without active management many will revert to coarse, species‐poor grassland and eventually to scrub. The reintroduction of stock grazing is a potential solution to this problem, but has not been tested in upland forests. Here we present results from 9 years of monitoring the effects of cattle grazing on the diversity and composition of riparian pasture vegetation in an upland conifer forest in northern Scotland. 2.
There were two treatments, late summer grazing and ungrazed. The average stocking density in the grazed treatment was 2·25–2·5 cows ha−1. The cattle were free to range over the entirety of the 40‐ha experimental site from early August to late September each year. 3.
Assessments of plant species richness and abundance were made in 1988 (prior to the commencement of grazing), 1991 and 1997, in three of the main riparian vegetation types. These were ‘Flush’ vegetation associated with calcareous springs, acid Agrostis capillaris–Festuca ovina grassland (‘Grass’), and Juncus effusus rush pasture (‘Juncus’). Assessments were also made of grazing impacts, cattle usage and water table depths. 4.  Grazing had a significant effect on plant species richness, which declined in ungrazed plots and remained static in grazed plots over the 1988–97 period. There were no recorded effects of grazing on species abundance, nor on the frequency of rare sedges and herbs of particular conservation importance. Litter cover (dead plant material) was significantly higher in ungrazed plots, which may be a causal factor in declining richness values. 5.
Cattle utilized Grass and Flush vegetation to a significantly greater degree than Juncus vegetation, and this appeared to be related to forage availability rather than wetness as represented by water table depth. 6.  Cattle grazing is of potential value as a management tool for species‐rich grasslands in upland forests provided that: areas to be grazed are large enough to minimize localized impacts and allow free ranging of the cattle; the economics and practicalities of stock husbandry are considered; the type of grazing management used is linked clearly to management objectives.
Habitat preferences of great bustard Otistarda flocks in the arable steppes of central Spain: are potentially suitable areas unoccupied?
Authors: Lane Simon J. , Alonso Juan C. , Martín Carlos A. 
Published: March 2003

Summary

Great bustards Otistarda are globally endangered and 50% of the world population now occurs in agro‐steppe habitats in Spain. An understanding of the relationship between land use and the species’ habitat requirements is necessary to predict the consequences of land‐use change on this declining species.
A 2‐year study of great bustard substrate preferences was conducted in a large region in central Spain where most cereals are still cultivated in a traditional 2‐year rotation.
Great bustards showed year‐round selection of stubble fields, but avoided ploughed and uncultivated areas. Other substrate types were variously selected, avoided or used in proportion to availability depending on season. Patterns were consistent over 2 years.
Human artefacts such as roads, tracks and powerlines were avoided.
Variables correlating with flock locations could not discriminate between occupied and unoccupied but apparently suitable areas of traditionally managed cereal steppe. This suggests that great bustard distribution in central Spain is not limited by inappropriate land use in steppe areas.
The evidence suggests that great bustards show fidelity to sites regardless of the availability of suitable habitat elsewhere. Settlement patterns are probably determined by the presence of conspecifics rather than habitat cues. This result demonstrates the value of integrating observations of habitat use with knowledge of species’ behaviour in order to understand distribution more fully.
We propose that conservation efforts should be directed towards securing traditional lek sites and we make three recommendations: first all great bustard lek sites should be identified; secondly, existing European Union legislation should be used to protect these and to ensure that compatible land management practices are applied or maintained; and finally, research programmes should be conducted that aim to enhance the conservation value of stubble fields rather than simply demonstrate their selection.
Ecology and genetics of wild‐living cats in the north‐east of Scotland and the implications for the conservation of the wildcat
Authors: Daniels Mike J. , Beaumont Mark A. , Johnson Paul J. , Balharry David , Macdonald David W. , Barratt Elizabeth 
Published: March 2003

Summary

The wildcat is considered to be threatened by interbreeding with the domestic cat. As a result of interbreeding the definition of a wildcat in Scotland is contentious. Many authors consider pelage characteristics to be diagnostic, yet few data exist on sympatric cats with different pelages.
A study of 31 wild‐living cats was conducted from 1995 to 1997 in an area associated with wildcats. Seventy‐four per cent of cats caught had striped tabby pelages while 26% had other (non‐tabby) phenotypes.
On the basis of data from eight nuclear DNA microsatellite loci there was no strong evidence of two groups, and tabby and non‐tabby cats did not depart significantly from Hardy–Weinberg equilibrium.
There were significant differences in gene frequencies and genotypes between the two pelage types. Non‐tabby cats were also significantly more similar to domestic cats than tabby cats, although still noticeably differentiated from them.
There were potential parent–offspring and sibling–sibling relationships between and within tabby and non‐tabby cats, suggesting recent interbreeding. On average, however, non‐tabby cats were genetically less related to each other than tabby cats.
Radio‐tracking revealed that non‐tabby adult females had significantly larger home ranges than tabby adult females. However, for all other aspects of home range size, social organization, activity patterns and habitat use there were no significant differences between cats of different pelage type.
The implications of these results are that traditional approaches for attempting to distinguish wild animals in the face of interbreeding with their domestic forms are neither accurate nor effective. Instead, conservation should focus on mechanisms for dealing with groups of animals below the species level.
Specifically for the wildcat in Scotland, conservation should focus on protection by area. If domestic cat controls were conducted within specified areas then the potential threat posed by interbreeding would be reduced.
Predicting plant species’ responses to grazing
Authors: Vesk Peter A. , Westoby Mark 
Published: March 2003

Summary

The aim of this study was to identify whether plant species show consistent responses to livestock grazing. The analyses were based on 35 published studies from Australian rangelands providing 55 species response lists. The primary data set comprised 1554 responses from 829 species.
Eight‐hundred and twenty‐nine species were categorized as increasers, decreasers or neutral under grazing. Of 324 species that occurred in at least two response lists, 133 (41%) responded inconsistently, increasing at least once and decreasing at least once. While 59% of species responded consistently, these results suggest that our ability to predict vegetation change under grazing is limited.
Particular species were not inherently more or less consistent. Rather, as species occurred in more trials, the likelihood of at least one opposite response increased; no species that occurred at least eight times was wholly consistent. A binomial model indicated that the probability of an opposite response, across all species, was 0·275.
Contrary responses within species must result from context rather than from species’ traits. Species were more likely to decrease in response to grazing at lower rainfall than at higher rainfall. Forbs tended to increase under grazing at sites where wet seasons were cooler. Changing the grazing animal was weakly correlated with change in response direction, although not enough for it to be useful for manipulating pasture composition. We found little support for ideas that different responses within species are due to differences in alternative forage available, or due to non‐linearity of response to grazing intensity.
At present it appears we can predict species response direction about three‐quarters of the time, at a continental scale. This represents an upper limit of the reliability of prediction based on species’ traits alone. Presently we do not know what aspects of the context might allow us to predict reliably the remaining one‐quarter of responses.