The relationship between male aggressive behaviour and population variables in the bank vole (Clethrionomys glareolus (Schreber, 1730)) was studied using two large (550m2) field enclosures. Known populations were established in each of the enclosures, and followed by live trapping. In an attempt to manipulate the level of aggressive behaviour in one (the experimental) enclosure with respect to the other (the control) a majority of the founding males in the experimental enclosure were castrated. Laboratory arena testing was used to study the behaviour of adult, castrated and immature male voles. It was demonstrated that both castrated and immature male voles were significantly less aggressive than adult males. Adult males were found to fight less with castrated and immature males than with other adults. Castrated males sometimes exhibited retaliatory behaviour when approached by either an adult or immature male, but overt aggressive behaviour rarely resulted. Immature males were very rarely aggressive. Observation of behavioural interactions in the field (at a bait point) showed them to be qualitatively different to those observed in the laboratory arena; voles appeared very wary of each other, and many interactions observed were characterised by mutual avoidance or flight. Oveitaggressive behaviour was rarely seen. It can be inferred that voles do fight in the field, because they commonly exhibit small wounds on rump, tail, and face; these could however, be sustained in the confinement of burrows, where escape and mutual avoidance are less possible than at a bait point, and which may be more closely paralleled by the laboratory arena. Significantly more adult males in the enclosures showed fresh wounds than did castrated or immature males, or adult or immature females. The number of voles in the experimental enclosure increased significantly faster than did the number in the control enclosure; the density in both enclosures was also significantly higher than commonly encountered in the wild. The difference in numbers between the two enclosures was due to a difference in the number of immature animals entering the trappable population; mortality of marked animals in both enclosures was very slight but mortality of infants was significantly higher in the control enclosure than in the experimental. Reproductive inhibition of adult and immature animals of both sexes was observed in both enclosures. At the same time, extremely young animals trapped in the wild populations were found to be sexually mature. The differences in the use of space by different age and sex classes between the two enclosures were also investigated. The study demonstrated that male aggressive behaviour had a significant effect on the population variables of bank voles at the high densities and at the high rates of population growth observed in large enclosures. The findings are discussed in the light of several hypotheses put forward to explain population regulation and cyclic changes in numbers of Microtine rodents.

The occurrence of wild canids living in close association with man is documented, and it is seen that foxes living in suburbia are a unique British phenomenon. Foxes have lived in London for at least 35 years, and have now permanently colonised most suitable habitats. The various body measurements of suburban foxes are compared with similar data for other populations. It is shown that the tail is shorter than in populations from regions with colder winters, the other body measurements varying from one population to another but with no obvious pattern. Various age determination techniques have been applied to the Red fox, but for the majority of techniques separation of year classes is impossible after eighteen months of age. The only technique that has proved of value is the use of incremental lines in the tooth cementum, particularly in the premolar teeth of the lower jaw. Growth curves have been constructed for animals up to six years of age. Using the age of the animals as determined by cementum lines, a life cable for suburban foxes has been constructed. These data are used to compare the structure of the suburban fox population (subject , to limited control operations) with that of a fox population subject to intense control. Survival curves have been constructed. It is shown that only the ratio of young : adults is affected by intense control operations, and that the rate of adult mortality is identical in both populations. The significance of this is discussed in relation to rabies and sarcoptic mange. The general health of the population is illustrated using spondylosis deformans as an example. This condition has not been reported previously in foxes. The food habits of suburban foxes have been examined. The various techniques available have been evaluated, but only stomach contents and den litter proved of value in the present study. The results are discussed in relation both to other fox food studies and the prey species available in London. The validity of the term "suburban fox" is considered, comparing the data presented here with similar data for other fox populations.

Vocalizations of the largely nocturnal Japanese Brown Hawk Owl Ninox scutulata japonica were studied, with particular reference to the function of vocal communication. The adult owls were found to have thirteen types of vocalization and three non-vocal sounds with the possible addition of one other vocal sound. Nestlings had four vocal and one non-vocal sound. The development of the vocal repertoire was also studied from captive juveniles. Most of the vocal repertoire was recorded and sonagraphically analysed, and their behavioural contexts were investigated to give an idea of their various functions. The main function of primary calls was in interactions with conspecific birds from a distance. The daily calling of territorial males was not time-related and appeared to be greatly influenced by the intraspecific environment. Seasonal production was concentrated during breeding activity, showing four peaks which are discussed in terms of territorial, sexual and family interactions. The unusual vocal activity of a replacing male was studied and gave valuable additional information. Primary calls were also considered to convey different types of information through variation in their physical structure. From the examination of calls in natural conditions and in aggressive responses to playback, variations of frequency and rate were related to location in the territory, the breeding cycle and the caller's motivational state. There were consistent individual variations in temporal and frequency features of the calls. Playback of neighbour and stranger's calls and that of the mate and other females' calls at various locations in the territory elicited differential responses, suggesting individual recognition by voice. A general description of the species, including their classification, distribution, migration and inter-racial differences, is also given.

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.

No description available.

No description available.

No description available.

In this study set-aside development was monitored (1989-1992) at Aldroughty Farm, Morayshire as part of an integrated project looking at plant and animal dynamics in set-aside, crop and semi-natural habitats. The vegetation, seed bank and seed rain were monitored in adjacent set-aside, semi natural and cropped areas. Initially set-aside vegetation consisted of annual arable species, but wind dispersed species and longer-lived perennials invaded rapidly. This process was more rapid on smaller plots and ingress of perennials occurred more quickly closer to the field margin. There was little invasion from adjacent semi-natural habitats and the field margin was the most important source of colonising species. Cropped areas were not significantly affected by adjacent set-aside. Seed banks were analysed using germination and extraction techniques which gave different estimates. Highest densities were found on set-aside land indicating the problems associated with returning set-aside to agricultural production. Changes in the seed bank were less apparent than in the vegetation, but within-year variation was great and carryover of seeds from October to March was low. The seed rain was monitored using gravel traps. Densities were highest on set-aside and lowest in the crop and wood. Individual species exhibited different phenologies in seed shedding, but peak deposition coincided with cutting. Dispersal from the set-aside into the crop was very low and dispersal distances were small. Vegetation and seed rain were similar in species composition in the set-aside areas. Although the seed rain was similar to seed bank samples taken immediately after seed shed, a large proportion of seeds did not enter the seed bank. Set-aside land did not develop into semi-natural habitat, however species diversity increased and the land provided a food source and an undisturbed habitat for animals. The real concern is the return of set-aside land to agricultural production, because of increased seed bank densities.

1. A phosphorus budget was calculated for the Loch of Strathbeg from 24/4/1978--24/4/1980. The loch is on an exposed site in the north-east corner of Scotland, has 2 an area of 2.01 km2 and a mean depth of 0.75 m. The loch is 'L' shaped and conveniently divided into long and short arms: the former draining to the sea. The catchment of 55.7 km2, is glacial ground moraine over-lying metamorphic rocks, on which grazing and arable fanning is carried out. There was no major human sewage input to the loch. 2. From October April an average of 1760 Grey Lag and 2740 Pink-footed Geese roosted on the loch. Each night a single Grey Lag deposited a mean of 332 mg P after feeding on barley grain and 211 mg P after feeding on grass, while a Pink-foot deposited 234 mg P and 172 mg P respectively. Extrapolations related to body weight were made to the less common species feeding on similar food. Published measurements of phosphorus input by gulls were discussed and new predictions were made from published energetic equations. The mean phosphorus input to the loch from birds totalled only 295 kg P yr-1 or 5.7% of the total input, However faeces probably fell directly to the sediment, where they were responsible for about 16% of the phosphorus loading. 3. There are five streams draining into the loch and a few small areas drained by groundwater. 83% of the area drains into the shallow short arm causing accelerated flushing and uneven loading. Separate phosphorus predictions were made for each stream, groundwater, rainfall and tidal input. Of these 90% (4,386 kg P yr-1) entered the short arm. 97% was from the catchment, 0.4% from rainfall and 2.3% from tides. The long arm had no direct tidal input, and of the total (482 kg P yr-1), 93% was from the catchment and 7% from direct rainfall. 4. The loch was shown to be a net sink for both reactive and non-reactive phosphorus. The output of reactive phosphorus as a percentage of the input varied from 3% in the summer to 34% in the winter and total phosphorus 55% to 60% respectively. The loch was also a sink for monomeric silica and total oxidised nitrogen. Ammonium was generated within the loch during the autumn, and the concentration of major ions was related to marine influence. 7. Microcosm experiments investigated the change in concentration of dissolved nutrients in the presence of sediments and primary producers. Winter conditions were simulated and showed that reactive phosphorus and oxidised nitrogen were removed from solution but that ammonium and silicate increased in concentration. Simulated summer conditions with growths of rooted macrophytes in the light resulted in a rapid removal of all the above mentioned nutrients from solution. This showed the effect of primary producers in stripping nutrients from solution and maintaining low concentrations throughout the summer. 8. After a spring bloom of the diatom Tabellaria fenestra, the water column cleared and most of the loch sediment was covered by growths of rooted macrophytes. The submerged vegetation was surveyed and mapped. Generally the less rich long arm was covered by Chara whilst the short arm held a more diverse flora. During August 1979 the macrophytes in the long arm had a significantly higher biomass and lower phosphorus concentration than the short arm. This reflected the water depth, the availability of reactive phosphorus in the sediment and in the water column. Mid-summer water concentrations of high dissolved oxygen and low carbon indicated intense photosynthesis, with the possibility of temporary carbon limitation. Between mid-August and January, avian herbivores consumed about 75 T dry weight of macrophytes (47% of August standing-crop). About 2 T was washed onto the banks, and the remaining 83 T decomposed in the loch. Reactive phosphorus released quickly became bound. 9. Total phosphorus results from this study were tested using published nutrient budget models. The parameters theta (theta = mpm/lp) and O (O = z/ℓ ) were devised. A relationship between the two was derived using data from this study and published sources. Assuming that the mean depth, rate of flushing, and mean spring concentration were known, the loading could be predicted. From a known, increase or decrease in loading, the ultimate spring concentration and the number of years taken to reach that concentration could be calculated. 13. It is concluded that an increase in summer phosphorus loading will largely destroy the macrophyte community especially Chara. This would prove detrimental to macroinvertebrates, the trout fishery and waterfowl feeding within the loch.