Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial, and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to the exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium-sized mammals, birds, companion animals (dogs and cats), and larger mammals (roe deer and wild boar) play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, “Candidatus Neoehrlichia mikurensis,” Rickettsia helvetica, and R. monacensis), Borrelia miyamotoi, and protozoans (Babesia divergens, B. venatorum, and B. microti) have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases.

With the global population becoming more urban and less rural, increasingly research has argued for concepts such as establish Green Infrastructure (GI) as a tool for enhancing wildlife survival and human’s living quality (e.g. Harrison et al., 1995; Benedict and McMahon, 2006). However, an interdisciplinary planning approach underpinned by ecological and social evidence has not yet been fully developed. This research therefore seeks to integrate an ecological network with a green space planning standard by exploring the use of biotope and sociotope mapping methods. Seeking a comprehensive planning that takes all green resources into account, a green space typology is firstly developed according to Taiwanese contexts for identifying green spaces from land use maps. In order to specify effective features of these green spaces to bird survival and user preferences, an insight was conducted into the relationship of ‘birds and urban habitats’, as well as ‘human preferred urban green spaces’ in Taipei City. Important environmental factors influencing bird distribution and influencing human experiences in urban green spaces are respectively specified and developed into an ecological value index (EVI) to detail potential habitats and a social value index (SVI) to evaluate recreational green space provision. Interestingly, proximity to green space appears to plays a more critical role in human preferences than bird survival in Taipei city; size is important both as a habitat and for creating an attractive green space; and green space quality tends to be a more significant factor than its structure for both wildlife and people. Utilising the bio-sociotope maps, this thesis argues for a number of strategies: conserving, enlarging, or creating large green spaces in green space deficient areas; increasing ecological and recreational value by enhancing green space quality of specific characteristics; and tackling gravity distance by combining green space accessibility and attractiveness in optimising urban green structure. As these suggestions are a challenge to apply in intensively developed urban areas, barriers from land use, political mechanisms, technical shortages, and cultural characteristics are also explored with possible resolutions presented for facilitating implementation. It is clear that optimising a multifunctional GI for both wildlife and people requires interdisciplinary knowledge and cooperation from various fields. The EVI and SVI developed within this thesis create the potential for a more place-specific and quantifiable green spaces strategy to help better link ecological and social functions in urban areas.

<p>Urban areas are warmer than surrounding rural areas. During the cold of winter, warming increases surrounding host temperature and may improve the overwintering survival of marginally hardy insects like evergreen bagworms. Similarly, during the summer, it has the potential to increase the fecundity and abundance of sap feeding insect pests such as scale insects in ways that change the capacity of their natural enemies to regulate their populations. </p> <p>Although in parts of Indiana winters can be cold enough to kill bagworm eggs, they thrive in cities. I conducted field experiments to determine the extent to which impervious surface near an infestation could keep temperatures warm enough to affect bagworm survival during cold of winter. My results suggest that the percentage of live eggs inside overwintering pupae decreased as ambient temperature drops. This response was moderated by the presence of impervious surface around an infested plant. Eggs found in bagworms collected from host trees surrounded by more impervious surface had a higher chance of survival than those collected from trees with low levels of hardscape. However, impervious surface has its limit such that egg mortality was not buffered by impervious surfaces at temperatures at or below -21.67°C. Similarly, I also conducted field experiments with sap feeding insects on honeylocust trees, a commonly planted tree in cities. Hot sites had a mean daily temperature more than 1.5 °C warmer than cool sites and scale insects were more abundant and fecund on trees in the hottest part of Indianapolis compared to cooler areas. No differences were observed in rates of parasitism on the scale insect. However, I found strong density dependence relation between parasitoids and scales abundance at scale density at or below the levels present in cool sites. The top-down regulation was prevalent at or below a critical density of scale hosts. Conversely, bottom-up regulation was prevalent above this host density as pests benefit from bottom-up factors. This suggests that urban habitats helped the scales to escape biological control by resident natural enemies above critical density of scale hosts. </p> <p>My findings can be useful to landscape designers to design landscapes that are less prone to insect pests. My finding adds to a growing body of evidence that suggests that planting urban trees with lesser amount of impervious surface can help reducing the urban warming effect and increase the regulation from natural enemies. </p>