Browsing by Subject "urban"
Now showing items 1-5 of 5
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(2023)Urbanisation threatens species and biodiversity globally. Consequent habitat loss and habitat fragmentation force species upon one another, inevitably also increasing human-wildlife conflicts. Despite the situation growing dire for many organisms, studies also show species from a variety of taxa being able to adapt to urban environments. Most studies of primates’ ability to adapt to urban environments have been done on diurnal species. To my knowledge, the African lesser bushbaby (Galago moholi) is the only nocturnal primate in which this has been studied. To assess urban adaptability in another nocturnal primate, I present transect and recording data on the abundance of the white-tailed small-eared greater galago (Otolemur garnettii lasiotis) in an urban and rural environment in the biodiversity hotspot Taita Hills, Kenya. Sampling was done in Wundanyi town and Ngangao forest and the two locations were then compared by fitting a negative binomial as well as a Poisson model for recording and transect count data. Additionally, preliminary observations are made regarding behavioural and spectral acoustic adaptation, increased sociality, and colouration coupled traits. My results indicate O. g. lasiotis to be significantly more abundant in the town than in the forest. In the town, I observed a two-fold increase in total number of vocalizations and mean vocalization rate, and a seven-fold increase in total number of sightings and mean encounter rate, as indicated by recordings and transects respectively. This discrepancy in estimated abundance differences in location from transect and recording data (two-fold versus seven-fold) suggest that urban individuals vocalize less than rural individuals. The spectral profile of three vocalization types were studied and urban individuals exhibited significantly higher high frequencies in the clustered squawk vocalization. I found town dwelling individuals to be a part of a larger group or pair considerably more often than forest dwelling individuals. A dark morph, as opposed to a light morph, was significantly more frequently encountered in the urban location, whereas both morphs were encountered almost equally often in the rural location. In summary, O. g. lasiotis seems to be capable of adapting to an urban environment, as indicated by its’ greater abundance in the town than in the forest. My data suggest decreased vocalization rate, increased sociality, and colouration coupled traits being possible adaptations affecting O. g. lasiotis’ capability to inhabit an urban environment. Further research is required to draw conclusions on what factors and adaptations might allow for the high abundance of O. g. lasiotis in the town.
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(2023)Urbanisation threatens species and biodiversity globally. Consequent habitat loss and habitat fragmentation force species upon one another, inevitably also increasing human-wildlife conflicts. Despite the situation growing dire for many organisms, studies also show species from a variety of taxa being able to adapt to urban environments. Most studies of primates’ ability to adapt to urban environments have been done on diurnal species. To my knowledge, the African lesser bushbaby (Galago moholi) is the only nocturnal primate in which this has been studied. To assess urban adaptability in another nocturnal primate, I present transect and recording data on the abundance of the white-tailed small-eared greater galago (Otolemur garnettii lasiotis) in an urban and rural environment in the biodiversity hotspot Taita Hills, Kenya. Sampling was done in Wundanyi town and Ngangao forest and the two locations were then compared by fitting a negative binomial as well as a Poisson model for recording and transect count data. Additionally, preliminary observations are made regarding behavioural and spectral acoustic adaptation, increased sociality, and colouration coupled traits. My results indicate O. g. lasiotis to be significantly more abundant in the town than in the forest. In the town, I observed a two-fold increase in total number of vocalizations and mean vocalization rate, and a seven-fold increase in total number of sightings and mean encounter rate, as indicated by recordings and transects respectively. This discrepancy in estimated abundance differences in location from transect and recording data (two-fold versus seven-fold) suggest that urban individuals vocalize less than rural individuals. The spectral profile of three vocalization types were studied and urban individuals exhibited significantly higher high frequencies in the clustered squawk vocalization. I found town dwelling individuals to be a part of a larger group or pair considerably more often than forest dwelling individuals. A dark morph, as opposed to a light morph, was significantly more frequently encountered in the urban location, whereas both morphs were encountered almost equally often in the rural location. In summary, O. g. lasiotis seems to be capable of adapting to an urban environment, as indicated by its’ greater abundance in the town than in the forest. My data suggest decreased vocalization rate, increased sociality, and colouration coupled traits being possible adaptations affecting O. g. lasiotis’ capability to inhabit an urban environment. Further research is required to draw conclusions on what factors and adaptations might allow for the high abundance of O. g. lasiotis in the town.
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(2023)Atmospheric aerosol particles play a significant role in urban air pollution, and understanding their size distribution is essential for assessing pollution sources and urban aerosol dynamics. In this study, we use a novel method developed by Kontkanen et al. (2020) to determine size-resolved particle number emissions in the particle size range of 3-800 nm at an urban background site and a street canyon site in Helsinki. Our results show overall higher particle number emissions in the street canyon compared to the urban background. On non-NPF event days, the particle number emissions of 3-6 nm particles in the urban background are highest in the noon. The emissions to the size range of 6-30 nm are highest during the morning or afternoon at both sites, indicating traffic is the main particle source in this size range. The emissions of larger particles are relatively low. Seasonal analysis suggests higher emissions during the summer in comparison to the winter which might be linked to higher product of mixing layer height (MLH) and particle number concentration in summer. Further investigations into particle emissions from different wind sectors suggest higher particle emissions from the urban sector than from the road sector in the urban background, contrary to the results for NOx concentrations. More research is needed to better understand the underlying factors. In addition, a comparison between particle number emissions estimated using FMI measurement MLH data and ERA5 model MLH data reveals that FMI data provides a more reliable representation of the MLH in the study area. Overall, the methods show limitations in accurately capturing particle dynamics in Helsinki. Future studies should address these limitations by employing more accurate NPF event classification and refining sector division methods.
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(2023)Urban areas have a central role in human’s impacts on the planet. A persistent, fundamental and systemic transformation of urban areas to be more sustainable is a widely recognized pursuit. Involving a variety of stakeholders in decision-making and discussing how, why, and to whose benefit urban areas should be changed is central for governing urban transformations. The study elaborates which features and negotiations key stakeholders relate to sustainable urban transformation. This is done through a frame analysis, and a serious game is used in data collection to facilitate discussion between participants. The results of this study show how urban sustainability and transformation can be framed in many ways that highlight different aspects. Role of private businesses, a competitive setting between cities, trust between different groups and accountability to citizens are elaborated in the negotiations on sustainable urban areas. Urban transformation is discussed especially related to low-carbon traffic, greening urban areas, preventing climate-change related flooding, adding possibilities to participate decision-making and more adaptive city planning. The study concludes that open communication between stakeholders of urban transformation is crucial to build trust and understanding between groups, but demand for openness may contradict with the interest for urban areas to appear in good light to and desirable for businesses and new residents.
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(2021)Urban greenery is vital to the people in our increasingly urbanizing societies. It is diverse in nature and provides numerous life improving qualities. Traditionally urban greenery has been assessed with a top-down view through the sensors of aerial vehicles and satellites. This does not equate on what is experienced down at the human level. An alternative viewpoint has emerged, with the introduction of a more human-scale viewpoint. To quantify this human-scale greenery, novel and disparate approaches have been developed. However, there is little knowledge on how these modelling methods and indices manage to capture the greenery we truly experience on the ground level. This thesis is an undertaking to better understand what the greenery experienced by people on the ground level, termed humanscale greenery (HSG), means. The goal was to grasp how the various modelling methods, indices and datasets can be best used to capture this phenomenon. Simultaneously, the study tries to better comprehend how different people experience greenery. To achieve this, human-scale greenery values were collected via interviews at randomly selected study sites across Helsinki. These values were then compared to modelled values at the same sites. The methods and indices tested include modern approaches developed specifically for HSG and traditional greenery assessment methods. Along the greenery values, sociodemographic variables were collected in the interviews and compared to each other in relation to HSG values. The modelled values were on average smaller than HSG values. All methods indicated very strong or strong linear relationships with human-scale greenery. NDVI and semantic segmentation Green View Index (GVI) had the strongest relationships and least deviation. Land use (LU) and color based GVI had the highest error deviations from HSG. The sociodemographic assessment showed hints that age might affect the amount of experienced greenery, but this is uncertain. With a random sampling of interviewees, 25–34-year-olds and less nature visiting people were more common at sites with low HSG. Based on the results obtained here, many different types of novel methods are suitable for modelling HSG with strong linear relationships. However, also traditional greenery assessment methods performed well. It is difficult to curtail the experience of greenery into a single approach. A solution could possibly be obtained via the combination of methods. The results also advocate the usage of machine learning methods for greenery image segmentation. These cannot be applied everywhere due to data coverage problems, but alternative methods can also be used to fill in gaps. The significance of age on the experience of greenery needs further research. Because urban greenery’s benefits are known, attention should also be given onto how different kinds of people are able to experience it. In the future we should also discuss the meaningfulness of assessing absolute greenery in comparison to the types and parts of greenery.
Now showing items 1-5 of 5