Urban trees and biodiversity in Cork city
Biodiversity is poorly quantified in urban landscapes and is not effectively incorporated into urban planning and policymaking. Land-use change (e.g., urbanisation) is one of the key drivers of biodiversity loss. Furthermore, urbanisation is expected to increase from 50 to 70% by 2050. The CSO reported a 0.6% decrease of residents living in highly rural areas of Ireland (2011-2016), including a 5.5% increase in residents living in independent urban towns. Urban trees have a broad range of ecosystem services; it is likely that many of these services will become increasingly important due to climate change pressures (e.g., changing climatic conditions, extreme natural occurrences). This thesis examines the role of urban trees/green spaces in supporting the biodiversity of other taxa (lichens, invertebrates, birds, and ground vegetation) in Cork city. There was a total of 102 individual trees studied across 6 Cork city sites, including the UCC arboretum (n=26); Cork city Marina (n=12); the Atlantic Pond (n=17); Kennedy Park (n=11); The Lee Fields (n=18); Fitzgerald’s Park (n=18). A full survey of all 4 taxa was conducted per tree, including the use of sticky traps for invertebrates; quadrat sampling for both vegetation and lichens; and observational point-counts for birds. There were no significant differences/associations between the species richness of the various taxa and the species of tree. This could be due to a limited number of replicate trees, which can be expected with an observational-based approach. However, community-level analyses have shown significant variations in the taxa communities among the 6 sites (p<0.001 for all taxa). These data suggest that the type of urban site is significantly associated with biotic community composition. Additionally, the research investigates the relationship that microclimate (light intensity and temperature) and canopy openness have with urban tree species. Microclimate data loggers were deployed at the base of all trees for each experiment and hemispherical canopy images were taken to determine canopy openness in Fitzgerald’s Park. In general, there were no, or little associations found between microclimate data, canopy openness and biodiversity. Thus, the assessment of the hypothesis that microclimate conditions impact taxa communities was inconclusive. Overall, the study supported the hypothesis that urban trees and green spaces support a large variety of individuals from other taxa and provides a baseline for biodiversity in Cork city, specifically regarding future studies and urban planning.
Urban trees, Urban biodiversity, Ecology, Cork, Lichens, Birds, Invertebrates, Ground vegetation, Urban green spaces
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