This study investigated the ecology of three species of Zygaenid or Burnet moth, the Narrow bordered five spot burnet or Talisker burnet (<I>Zygaena lonicerae jocelynae</I>) a sub-species confined to three locations on the Isle of Skye, the Transparent burnet (<I>Zygaena purpuralis</I>) restricted to between 25 and 30 'colonies' on the west coast of Scotland (also described as a sub-species) and the Six spot burnet (<I>Zygaena filipendulae)</I>, which although common is restricted to coastal areas in Scotland. The burnets of Scotland have been the subject of some conservation concern given their limited distributions in Britain and the discovery that the New Forest burnet colony in Argyll was under severe pressure from an increase in sheep grazing. This concern has focused attention on the other restricted burnets. All three species occur at Talisker, Isle of Skye, where autecological studies of the species were undertaken. This data could then be examined in terms of the requirements of the three species. Grazing levels are crucial to the ecology of all three of the species and it is the variation in the vegetation structure occurring at each specific area within Talisker which allows the three species to co-occur there. The Talisker burnet is restricted to ungrazed undercliff grassland where its foodplant, <I>Lathyrus pratensis </I>grows in abundance. Within the ungrazed areas there is considerable variation in the vegetation heights available and in areas were the vegetation is short the larvae are found relatively high in the vegetation, as are the pupae of this species. Genetic analysis of populations of <I>Z. purpuralis </I>indicate that they are quite diverse, having maintained a high rate of genetic variability between populations which are relatively close and indicates that populations greater than 10 kilometres apart have very little interchange. To conservation population of <I>Z. purpuralis</I> grazing is required on several <I>Z. purpuralis </I>sites to maintain the short vegetation required, while at Talisker <I>Z. lonicerae</I> requires early successful areas which are created by natural rockfalls and soil slippage.

A constitutive <I>lux</I>-marked biosensor, <I>E. coli</I> HB101 pUCD607, was developed as a novel, acute, 'fingerprinting' technique by which individual pollutants, and whole effluents, could be identified and quantified. In this way, the advantages of both chemical analysis and toxicology were encompassed in one technique. An assay technique for obtaining temporal response curves was developed by injecting the biosensor into toxic samples, and then measuring luminescence continuously for 5 minutes. An algorithm was formulated, and implemented as a simple computer program, by which 'unknown' temporal response-curves could be compared against a database of 'reference' pollutant response-curves. Two different techniques were derived for analysing the output data; a binomial (yes or no) 'best-fit' technique, and a continuous 'comparative-fit' technique. These techniques were validated by 94% identification success for inter-comparisons of 7 pollutants, each at 5 concentrations, and 100% identification success of four pollutant spikes in three environmental samples. The technique was tested on three complex environmental effluents. Cu was identified as the main pollutant in a distillery effluent, and Zn the main pollutant in a metal processing effluent. Identification was successful despite the presence of complexing substrates and co-pollutants. The technique could also differentiate between three complex effluents and four artificial complex effluents without the need for actual pollutant identification. In conclusion, this technology can be used to 'fingerprint' any form of pollution that is bioavailable to the biosensor, without the need for prior knowledge of sample chemistry. This represents a potentially valuable tool for toxicity assessment and screening.

The aims of the project were to study the effects of public pressure on the soil, fauna and flora of picnic sites which had developed in a variety of semi-natural habitats, so that conclusions could be drawn regarding the effects of trampling on sites in general and variations in the reactions of different habitats noted. Public pressure was quantified using a simple mapping technique and correlations between the level of trampling and the vegetation, soil and fauna of each habitat were established. A more detailed examination was made of the response of the vegetation to treading. Experiments with an artificial trampling machine on greenhouse grown plants produced interesting but unexpected results. The damage caused by deliberate treading on a previously untrampled site depended on the manner and timing of the treading, and on the original plant community. Experiments on the sites charted the floristic changes when public pressure was reduced or removed. It was found that compaction of the surface soil affected the entire profile. Animals on picnic sites responded directly to the presence of visitors and indirectly to changes in the vegetation induced by trampling. Pliable plants which can regenerate rapidly were found to be most resistant to public pressure. These species (usually Gramineae or Cyperaceae) invaded trampled areas when the original flora was damaged by treading. The same resistant species were found on trampled areas over wide climatic, edaphic and geographical ranges. They could be encouraged on amenity sites by cultivation, so that a more resistant sward could be produced, but only so long as this degree of artificiality is acceptable on the site.

Traditionally, the southern botanists, facing much richer floras, dedicated their attention more to the disciplines of taxonomy and phytosociology. This created a detailed and extensive floristic knowledge on plant geographical distribution, poorly supported by an understanding of dynamic processes. This project was aimed to fill as much as possible of this lack of ecological approach in Mediterranean vegetation studies in Italy. The study area was located in the Campania region, southern Italy. The thesis programme was conceived as a series of investigations, starting with surveys and gradually narrowing down to specific experiments and analytical investigations. Site history is discussed as a key factor for the understanding of the regional variation of vegetation. Multivariate methods (Cluster Analysis, Principal Component Analysis) were used to analyse the vegetation composition data. They suggested that most observed changes of vegetation could reflect successional and degradation gradients rather than environmental differences. This view was supported by historical evidences of past-disturbance and dynamic processes, by study of ancient manuscripts, maps, paintings and photographs and by demographical data. The results of observations of both natural and experimental fires showed high ability to recover by vegetative sprouting and seed germination. Most fires were followed by 100&'37 survival with few exceptions in the case of the dry winter 1989 and of very hot fires. In these cases, Erica arborea was the most sensitive species. In contrast to fire, cutting depressed regrowth at one of the study sites located on most exposed and dry conditions. Recolonization after complete vegetation removal showed a different succession with an initial dominance of Dittrichia viscosa, later suppressed by Cistus spp. and Ampelodesmos mauritanicus. E.arborea did not recolonize after this kind of disturbance.

1. An understanding of the natural regeneration of Scots pine was considered essential for effective management of the Glen Tanar native pinewood. The aim of this project was to review previous work on regeneration of Scots pine and to carry out experiments at Glen Tanar which further this knowledge. 2. Two contrasting study areas, the Bush and Monrae, were chosen to represent extremes from the range of site types found at Glen Tanar. Experiments involved both naturally disseminated and sown Scots pine seed. Individual germinants were identified as soon as possible after germination and then subsequent survival and development of seedlings up to two years old were determined. The effect of browsing on older seedlings was also assessed. 3. Cage experiments indicated that seed predation by birds and rodents was responsible for. a loss of up to 85% of seed between reaching the ground and germination. 4. Ground treatments were carried out to produce a range of seedbeds. There was a large variation in production of germinants on different seedbeds but only small differences in the subsequent survival of seedlings. Very few seedlings became established in intact vegetation and only ground treatments which removed field, moss and litter layers gave a consistent increase in germination. 5. Temperature and moisture measurements showed that conditions were generally more favourable for germination on bare humus substrate than in the and moss and litter layer, Shallow trenches cut to the depth of the mineral soil also appeared to provide favourable conditions for germination. 6. Mortality was generally highest among seedlings less than four weeks old. The most important factors causing early losses were slug damage and desiccation. On a freely-drained site, winter mortality was low but on a poorly-drained site, with a steeper slope, surface-erosion and frost- lift caused fairly high losses during winter. 7. Exclusion of grazing animals did not have a significant effect on the early establishment of seedlings. During the second season luxuriant growth of ungrazed grass competed with pine seedlings and reduced development. Outside the exclosure seedlings were browsed by rabbits. Observations of planted and naturally regenerated Scots pines and birches showed seedlings attracted larger browsing animals, particularly deer and capercailzie, as they reached above the level of the field layer. Most birch browsing occurred in summer, while pine browsing was most severe in winter. It was concluded that the density of naturally regenerated seedlings could probably be increased in most parts of the native pinewood by 'screefing' the ground surface. It would not be necessary to fence regeneration areas, however, until an adequate stock of seedlings becomes established in the field layer.

Red squirrels (Sciurus vulgaris) returned repeatedly to particular trees (defined as patches) within a Scots Pine (Pinus sylvestris) plantation to feed on pine seed endosperm which they extracted from within the cones (defined as the prey). The present study tested a hypothesis that such Favoured Trees (FTs) allowed faster ingestion of seed endosperm than trees which were avoided. Cone morphometrics and their variability differed markedly amongst trees and FTs had different sized cones than Randomly Selected Trees (RTs). Cones from FTs had markedly more viable seed within them than cones of the same length from RTs. There was more seed in larger cones. Squirrels took longer to extract seed from larger cones. Non-adults took much longer to strip a cone of a given length than did adults, and this difference became significantly greater with increasing cone length. FTs had twice as many cones as RTs but this had a weak effect on the efficiency of finding each cone. However, search efficiency was higher in trees where more cones were eaten in one meal, particularly in spring and summer when feeding was concentrated in trees with lower than average proportions of split cones. A seasonal pattern of cone size selection repeated itself in successive crops which showed adult squirrels preferred trees with middle sized cones but avoided very small and very large cones. Non-adult squirrels selected smaller cones than adults. Avoidance of small cones by adults and the differences between age groups were as predicted by the maximisation of ingestion rate hypothesis, but avoidance of the largest cones by adults was inconsistent with the hypothesis. Inclusion of the increased energetic costs of holding and manipulating larger cones might explain the latter discrepancy. All the other findings of the thesis were consistent with the hypothesis.

The diet, habitat preferences, and foraging behaviour of stoats and living in an area of farmland near Newburgh, Aberdeenshire were studied over a period of years. Additional information was collected from nearby areas of sand dune and mixed farmland and woodland. The differences in size between the species, and sexual dimorphism9 were assessed by measuring' nine body parameters of 54 stoats and 87 weasels. Trophic niche overlap was assessed quantitatively from an analysis of 301 scat and gut samples. The diets of both sexes of both species were very similar though larger predators tended to take larger prey items more often. Radio-tracking techniques were applied to both species during the last two years of the study, over 1300 hours of field observations being made. Both species hunted in the same areas and no differences in habitat preferences were noted. Niche overlap in habitat utilization was assessed quantitatively for ten farmland vegetation-type classifications. Male weasels were territorial. Territoriality in male stoats was not established. Female stoats had contiguous exclusive home ranges but no territorial defense was observed. Female weasels had non-contiguous home ranges. The home ranges of different sexes and different species overlapped. Home range area was much larger than other published estimates but the area within the minimum convex polygon boundaries that was exploited by the animals was similar to estimates from areas of homogeneous habitat. The abundance and distribution of small mammals were monitored in known steat and weasel hunting areas. Breeding of small rodents ceased between November and March/ April and numbers were very low in some habitats by March. It was concluded that exploitation competition between stoats and weasels for small rodents in spring was very probable but that differences in access to small rodents and the presence of some alternative prey at times of small rodent shortage enabled both species to coexists The possibility of interference interactions occurring was established but thought to be unimportant in maintaining the coexistence of the two species on farmland.

Data över förekomst av två storleksklasser (0-150 mm och &gt;150 mm) av Europeisk ål (Anguilla anguilla) i vattendrag på svenska västkusten hämtades från SERS (Svenskt ElfiskeRegiSter vid SLU). Dessa analyserades genom logistisk regression för att avgöra vilka olika makrohabitat-, landskaps- och hindervariabler som bäst kunde användas för att förutspå förekomst av ål. Resultatet visade att det för makrohabitatvariablerna var vattendragets bredd, vattenhastighet och vegetationsmängd som bäst förutspådde förekomst av båda storleksklasserna. För landskapsvariablerna var det avstånd till mynningen, fosforkoncentration och vattentemperatur som bäst förutspådde förekomsten av båda storleksklasserna. Därtill var även sjöprocent en viktig variabel för att förklara förekomsten av den större klassen ål. För variabler som beskriver vandringshinder var det dammar, ålyngelledare och naturlika fiskvägar som bäst förutspådde ålförekomst av båda storleksklasserna. Därtill var även avstånd till uppströms hinder viktigt för att förklara förekomsten av större ål (&gt;150 mm). Mängden lämpliga tillväxthabitat för ålen kan därför troligtvis ökas genom åtgärder riktade mot lokalens vattendragsbredd, vattenhastighet och vegetationsmängd.

No description available.

Populations of woodmice (Apodemus sylvaticus), bank voles (Clethrionomys glareolus) and field voles (Microtus agrestis) were studied by five-trapping in Sitka spruce plantations at Hamsterley Forest, northeast England, from February 1990 to June 1992. The study was carried out at two distinct spatial scales. At the coarser spatial scale, the effects of successional change and of spatial (intersite) heterogeneity within the forest were compared by censusing rodent commmunities in sites representing three successional stages: mature plantations (about 40 years after planting), clear-fellings and young plantations (5-8 years after planting). In, mature plantations woodmice and bank voles were both abundant, , in clear-fellings the former were usually dominant and in young plantations field voles were also abundant alongside' the other two species. Pooling all sites, in young plantations rodent communities had highest diversity and evenness, mostly because of an inter-site component @-diversity). On a site-by-site basis, in young plantations communities had neither higher a-diversity nor evenness than in mature plantations. Clear-fellings showed least diversity and evenness. Multivariate analyses revealed marked taxonomic and structural changes in vegetation during succession and how the rodents responded to such changes. Within young plantations bank voles were associated with dense ground cover, provided mostly by heather. Field voles. were associated with the non-palatable grass Deschwnpsia flýxuosa and to palatable grasses as well. Woodmice were habitat generalists, but their abundance was negatively correlated with that of field voles. Spatial heterogeneity in soils explained much of the inter-site variation in ground vegetation which in turn explained much of the P-diversity in rodent communities in young plantations. At the finer spatial scale, populations of woodmice and bank voles were studied by monthly trapping in five 0.8 1 ha grids within an habitat mosaic produced by the felling of a plantation of mature Sitka spruce. Inter-grid movements were frequent for both species, but especially woodmice, which also had larger home ranges. Population dynamics of woodmice in the whole mosaic were apparently similar to patterns described previously in other habitats, except that density-dependent reduction of survival and reproduction by late autumn was more severe than usual. Woodmice were more abundant in 1991 than in 1990, apparently due to increased seed supply. Bank voles, in contrast, did not show regular annual fluctuations in numbers. Although breeding stopped in both winters, population densities increased steadly during 1991 and remained high until spring 1992. Clear-felling of a part of the study area had little immediate effect on populations of either species; responses to clear-felfing were gradual rather than sudden. The experimental removal of tree brashings from recent clear-felfings scarcely affected the populations of woodmice, but made the clear-feUings unsuitable for bank voles, apparently due to the reduced availability of shelter. Habitat selection within the whole habitat mosaic was density-independent in bank voles, but density-dependent in woodmice. In the later species, demographic differences among local subpopulations accounted for most of the observed density-dependent changes in spatial distribution, although inter-grid movements also played an important part. * The responses of each rodent species to spatial and temporal heterogeneity and a possible role of density-dependent habitat selection in population regulation are discussed.