Studies on Formica lugubris Zetterstedt in Ireland (Hymenoptera, Formicidae)

This thesis is based on studies of Formica lugubris from 1972-1975. While this species' range is diminishing in Ireland, the nests are quite common in the State plantations of South Tipperary. It is not certain that the species is indigenous. Above-ground activity occurs from late-February to the end of October; foraging begins in April. Two territorial "spring-battles" between neighbouring nests are described. Most active nests produced alatae of both sexes and flights were observed on successive June mornings above l7.5°C air temperature. Both polygyny and polycaly seem to be rare. Where the nests occur commonly, the recorded densities are similar to those reported from the continent. Most nests persisted at the same site since 1973. The nest-sites are described by recording an array of nest, soil, tree, vegetation and location variables at each site. Pinus sylvestris is the most important overhead tree. Nests seem to be the same age as their surrounding plantation and reach a maximum of c. 30 years. Nearest-neighbour analysis suggests the sites are overdispersed. Forager route-fidelity was studied and long-term absence from the route, anaesthetization and "removal" of an aphid tree had little effect on this fidelity. There were no identifiable groups of workers specifically honeydew or prey-carriers. Size-duty relationships of workers participating in adult transport are described. Foraging rhythms were studied on representative days: the numbers foraging were linearly related to temperature. Route-traffic passed randomly and an average foraging trip lasted c. four hours. Annual food intake to a nest with 25 000 foragers was estimated at approximately 75 kg honeydew and 2 million prey-items. Forager-numbers and colony-size were estimated using the capture-mark - recapture method: paint marking was used for the forager estimate and an interval radiophosphorus mark, detected by autoradiography, was used for the colony-size estimate. The aphids attended by lugubris and the nest myrmecophiles are recorded.

Studies relating to the population dynamics of the European badger (Meles meles) in Ireland

European badgers (Meles meles) are an important part of the Irish ecosystem; they are a component of Ireland’s native fauna and are afforded protection by national and international laws. The species is also a reservoir host for bovine tuberculosis (bTB) and implicated in the epidemiology of bTB in cattle. Due to this latter point, badgers have been culled in the Republic of Ireland (ROI) in areas where persistent cattle bTB outbreaks exist. The population dynamics of badgers are therefore of great pure and applied interest. The studies within this thesis used large datasets and a number of analytical approaches to uncover essential elements of badger populations in the ROI. Furthermore, a review and meta-analysis of all available data on Irish badgers was completed to give a framework from which key knowledge gaps and future directions could be identified (Chapter 1). One main finding suggested that badger densities are significantly reduced in areas of repeated culling, as revealed through declining trends in signs of activity (Chapter 2) and capture numbers (Chapter 2 and Chapter 3). Despite this, the trappability of badgers was shown to be lower than previously thought. This indicates that management programmes would require repeated long-term efforts to be effective (Chapter 4). Mark-recapture modelling of a population (sample area: 755km2) suggested that mean badger density was typical of continental European populations, but substantially lower than British populations (Chapter 4). Badger movement patterns indicated that most of the population exhibited site fidelity. Long-distance movements were also recorded, the longest of which (20.1km) was the greatest displacement of an Irish badger currently known (Chapter 5). The studies presented in this thesis allows for the development of more robust models of the badger population at national scales (see Future Directions). Through the use of large-scale datasets future models will facilitate informed sustainable planning for disease control.

Life history of a native emydid turtle (Malaclemys terrapin centrata) on the remote oceanic islands of Bermuda

Diamondback terrapins (Malaclemys terrapin) are native to the remote oceanic islands of Bermuda and presently inhabit only four small brackish water ponds on a private golf course. The life history of this species is poorly understood on Bermuda and so the aim of this study was to fill these knowledge gaps, to compare the results with what is known from other areas in the North American range, and to inform the development of a local management plan. The results of a mark-recapture census revealed that ca. 100 individuals ≥81 mm straight carapace length live on Bermuda, of which nearly half (48.5%) were considered sexually mature. The population is dominated by females (sex ratio 2.9:1) and annual recruitment over the three year period was found to be extremely low (approximately two terrapins). Female diamondback terrapins in Bermuda nest almost exclusively within a limited number of sand bunkers on the golf course. Nesting commenced in late March or early April and ended in late August. Peak oviposition was observed in May and June. Clutch size averaged 5.1 eggs (range 0-10; SD 2.4) and the incubation period averaged 61.8 days (range 49-83; SD 10.5). Delayed emergence was documented, with 43.8% of the hatchlings remaining in their natal nests over the winter months. The mean annual hatching success rate was determined to be 19% (range 17.6-21; SD 1.9). Radio-telemetry was used to investigate the movements and survivorship of postemergent hatchling diamondback terrapins. The results indicated that mangrove swamps and grass-dominated marshes adjacent to the ponds are important developmental habitats for hatchlings. Yellow-crowned night herons (Nyctanassa violacea) were found to be significant predators of small terrapins during spring emergence. Small aquatic gastropods comprised 66.7% of the faecal samples analysed from the Bermudian population. Scavenged fish and vertebrate animal remains, terrestrial arthropods, polychaete worms and bivalves were consumed in lesser amounts. Sediment from the pond environment was found in 74% of the faecal samples analysed and is believed to have been incidentally ingested while foraging for the small benthic gastropods. Eco-toxicological analyses of the pond sediment, prey and terrapin eggs showed that the Bermudian diamondback terrapins live and feed in wetland habitats characterised by chronic, multifactorial contamination; principally total petroleum hydrocarbons, polycyclic aromatic hydrocarbons and a variety of heavy metals. This study found that some of those contaminants are accumulating in the gastropod prey as well as being transferred to terrapin eggs. This may be reducing the incidence of successful embryonic development for this species in Bermuda and may likely contribute to the observed low hatching rates. These collective findings indicate that the Bermudian population is very vulnerable to local extirpation.