The Lincolnshire Limewoods are a group of Ancient Semi Natural Woodlands within Central Lincolnshire that include the nationally important Bardney Limewoods National Nature Reserve. The woods, although fragmented and isolated by tracts of agricultural land, are reservoirs of biodiversity and contain large populations of Tilia cordata Mill. The current management aims are to increase the biodiversity within the woods, as well as to extend and improve the connectivity between the woodlands, with new planting. An understanding of the genetic diversity and structure of the Limewoods, both as individual woods and by comparison with woods from other regions of Britain, will help to inform management decisions. A pilot study was undertaken using RAPD markers which demonstrated the potential for these markers to amplify and identify individual T. cordata trees. Dominant markers are less informative than co-dominant markers, especially when trees may be closely related, and to facilitate this study a T. cordata enriched microsatellite library was constructed. The ten microsatellite loci designed for the genetic study amplified both T. cordata and closely related Tilia platyphyllos Scop. and were also able to identify hybridisation between the two species. T. platyphyllos and hybrid trees were detected in eleven of the Lincolnshire Limewoods and were associated with identification of private alleles within the T. cordata populations. The high levels of genetic diversity and low genetic variance which were found show that the Lincolnshire Limewoods’ populations are all similar. Comparison with populations from outside Lincolnshire show similar genetic diversity, with AMOVA ii conducted over all populations showing that only 4% of the variation could be allocated between the populations whereas 82% was allocated between the individuals within the populations. Weak isolation by distance was identified and would suggest that the Lincolnshire Limewoods should be treated as a single population group for management purposes. To increase the likelihood that T. cordata is used for replanting schemes, seeds should be taken from woods without hybrid populations and, preferably, should be screened to identify and exclude F1 hybrids. Tissue culture was considered as a potential source of planting stock for the Lincolnshire Limewoods to provide trees of known provenance with potentially rejuvenated characteristics. Preliminary tissue culture investigation showed that the initial treatment and age of the tissue before sterilisation is important in controlling contamination after sterilisation. Tissue collected in the spring, prior to leaf emergence, with the buds allowed to develop under clean laboratory conditions resulted in a reduction in the number of contaminated explants. In explant culture, roots were induced with application of the auxin naphthaleneacetic acid (NAA) and microshoots were induced with a combination of NAA and cytokinin, 6-benzyl-aminopurine (BAP). However, no rooted plantlets were produced. Further investigation into the use of somatic embryos as an explant source should now be considered as a possible way of reducing the chronic contamination that was experienced using axial buds.

Hedgerows have been a feature of the British countryside for many centuries and their value to wildlife particularly in farmed areas is long acknowledged. But farmland hedgerows experienced dramatic decline in the 20th century and efforts to halt this decline have been a focal point for agri-environmental activities, with hedge planting and management amongst the most popular options amongst farmers. Despite restoration of many thousands of kilometre of hedgerow under environmental stewardship, the rate of hedgerow loss exceeds the current rate of replacement. Information regarding the ‘performance’ of hedgerows as habitat for a range of wildlife is not lacking, although there is less current information regarding the biodiversity of the woody hedgerow itself as opposed to the grassy hedge bottom; I examine both elements of the hedgerow. There is less current information regarding invertebrates than for birds, plants or mammals. A lack of general monitoring has produced a deficit of knowledge of the role farmland hedgerows currently play in maintaining invertebrate biodiversity and what agri-environmental options have achieved. My objective was to compare and contrast the invertebrate faunas of hedgerows relatively newly-planted under agri-environmental schemes with existing hedgerow stock in order to investigate the biodiversity gains achieved by creation of new habitat. While it was true that overall the diversity of mature hedgerows was greater than that of new hedgerows, for some taxa newer hedges were ‘preferred’. There was evidence for the value of even relatively immature (~10 year-old) hedgerow habitats to overall invertebrate diversity. I did not use a single taxonomic group such as butterflies to ‘indicate’ diversity, but instead chose to take a view of the broad spectrum of invertebrates collected from both the hedge bottom and hedge top based on higher taxon approaches (notably order), which have been proposed as an adequate means of rapidly assessing the diversity of agricultural land. A suite of habitat variables including botanical diversity at hedge bottom and top, structural features including the height, width and density of vegetation, as well as weather data were recorded. While weather will always have the ultimate decisive influence on invertebrate activity, structural elements such as the sward height at hedge bottom and the density of the canopy are important to the invertebrate assemblage. As hedgerow conservation and management become increasingly important in the light of continuing declines, the ability to evidence the effects of interventions efficiently will be crucial. This research underscores the ongoing need for monitoring of hedgerow creation in order to verify whether biodiversity gains are achieved.

This thesis is concerned with Batesian mimicry in British Syrphidae (Diptera), and examines the question of whether the ifies gain protection from mimicry. Batesian mimicry is the resemblance of a palatable animal (the mimic) to a distasteful or otherwise protected animal (the model), such that protection is gained by the mimic. Syrphidae (hoverflies) are colourfUl but defenceless insects which often resemble members of the Hymenoptera. This study provides evidence that certain species of hoverfly gain protection from their resemblance to Hymenoptera. In collaboration with Liverpool Museum the British Syrphidae were matched by eye to presumed model Hymenoptera. Once presumed model/mimic pairs had been suggested, a comprehensive survey of three sites in the north west of England was undertaken during 1994. Each site was visited once a week and counts were made of all Syrphidae and Hymenoptera on three plots at each site. Mean frequencies of models and mimics were compared, and it was found that mimics usually occurred when.models were present, and models were usually more abundant than the mimics; the data were also analysed usingan analysis of variance, and it was found that for most species tested there was a significant covariance between the mimic and presumed model numbers. Survey work in 1994 and 1995 showed that bumble bee mimics follow model rank order on each site, but not on all individual habitat plots. One aspect of fly behaviour of a bumble bee mimic was also studied (time spent feeding on flowers) and compared to other hoverifies and the presumed model. The results showed that the time the mimic spent on flowers was not the same as that of the presumed model. In the quest to understand hoverfly predation, immunological techniques are developed to test wild bird blood for evidence of antibodies against hymenopteran venom. The theory is that birds which have learned though a nasty experience that a particular colour pattern is distastefUl will also avoid other similar patterns, i.e. Wa bird is stung by a wasp it may not predate a hoverfly resembling the wasp. The main conclusion is that there are specific and non-specific mimics, and that nonspecific mimics significantly covary with model numbers, but specific mimics do not, which is not what one might have predicted if these hoverilies really do gain protection through Batesian mimicry. Also, it is possible to detect an immune response against wasp venom in birds and a method has been developed to embark on field trials in the future.

Following failure to respond to antibiotic therapy, 56 patients (mean age 22yrs; range 15-46yrs) with recorded active Acne vulgaris were treated with a standard course of isotretinoin (1mg/kg body weight for 16 weeks). This study investigated the recovery and analysis of skin surface organisms from several skin sites at the start of treatment, 8 weeks into treatment, at the end of the course and 1 month post treatment. The number of anaerobic isolates - presumptive Propionibacterium acnes and also aerobic isolates recovered by appropriate media from each of three specific sites per patient were compared with age-matched controls of healthy volunteers. Patients and controls exhibited similar total numbers of organisms on the cheek, nares and toe web before treatment. Following treatment with isotretinoin the majority of patients had a significant reduction in bacterial numbers (1-2 orders of magnitude) on the cheek. Numbers in the nares and toe web did not show this reduction. Isotretinoin has no antibacterial activity in vitro or in vivo so the observed reduction would strongly suggest that the effect is mediated through alteration of the skin nutritional micro-environment. The clinic-based patients demonstrated high levels of isolates with antibiotic resistance from the outset; the resistance status of each patients’ skin microbiota was determined before, during and after treatment and the dynamics of the population from these sites was investigated. Previous studies of the nature of skin organisms and of the complex multifactorial mechanisms that lead to the eruption of acne have shown that P. acnes play a significant but as yet poorly explained role in the pathogenesis of the disease although it is traditionally the target organism for anti-acne therapy. The clinical samples were cultured using conventional methods to confirm the presence of P. acnes and staphylococci. Novel modifications of PCR amplification methodology were developed to enhance the detection of specific organisms. New protocols for comprehensive and detailed RAPD-PCR analysis of whole cell PCR were developed and employed to profile recovered isolates from individual patients before and after clinical treatment. RAPD-PCR proved to be a useful tool to survey changing bacterial profiles within the cohort. Isolates from some patients were highly similar to each other at the outset, but displayed increased diversity by the end of therapy. Interestingly, other studies have linked clonal populations of bacteria with high pathogenicity. Some patients appear to have acquired a strain which was not evident at their original sampling, but was present in other patients attending the same clinic. P. acnes persist in the environment and may be found on many inanimate objects, from where they could become a source for transmission. As there is some evidence of acquisition of strains from the environment, this is of considerable significance to the management of dermatology clinics throughout the country.