Caragh G. Threlfall

Macquarie University

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Nicholas Williams

University of Melbourne

Dave Kendal

University of Tasmania

Dieter F. Hochuli

University of Sydney

Stephen J. Livesley

University of Melbourne

Amy K. Hahs

University of Melbourne

Bradley Law

New South Wales Department of Primary Industries

Melanie Davern

RMIT University

Kirsten M. Parris

University of Melbourne

Kylie Soanes

University of Melbourne

Gábor L. Löveï

Aarhus University

Cooperative Institutions

John Wiley & Sons (United States)

University of Melbourne

Ecological Society of America

University of Toronto

Imperial College London

Instituto de Ecología

Centre National de la Recherche Scientifique

Natural History Museum

Universidad Nacional Autónoma de México

University of Göttingen

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Variation in Vegetation Structure and Composition across Urban Green Space Types

Frontiers in Ecology and Evolution (2016)

Caragh G. Threlfall Alessandro Ossola Amy K. Hahs Nicholas Williams Lee Wilson

The ecological sustainability and function of urban landscapes is strongly influenced by the composition and structure of the local plant community. Taxonomic composition generally refers to the identity of the species comprising the community, while we define structure as the presence of multiple canopy layers, as well as stems of varying diameter and age. These aspects of urban vegetation significantly influence the ecology of cities, yet they are generally poorly quantified across the range of natural and constructed plant communities present in urban landscapes. We quantified vegetation composition and structure to i) simultaneously assess their variation across four green spaces types (golf courses, public parks, residential neighbourhoods and patches of remnant vegetation) in Melbourne, Australia, and ii) investigate the relationship between vegetation composition and structure within these green spaces. The four green space types supported distinctly different plant communities. Vegetation composition in the residential neighborhoods differed significantly from the others (p<0.05), largely due to the increased richness of shrubs and cultivated plants, and the reduced presence of large trees. Residential neighborhoods had the highest plant species richness, although a large proportion of these species occurred infrequently. The structural complexity of understorey vegetation (calculated as % volume occupied) below 0.5 m was highest in remnant patches followed by golf courses, public parks and residential neighborhoods. The structural complexity of understorey vegetation in remnant vegetation patches was very similar to that of golf courses even though some of the latter were dominated by exotic plant species. Variation in the composition and structure of urban vegetation might have great implications for the retention of faunal diversity within cities because different taxa have specific habitat requirements. Hence, further understanding of variations in the composition and structure of both natural and constructed plant communities in cities will greatly improve our ability to create urban landscapes that enhance both plant and animal biodiversity.

Understory

Urban ecology

10.3389/fevo.2016.00066

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Citations (124)

Bat boxes in urban bushland are associated with inflated activity of an urban generalist bat, but not an altered community

Austral Ecology (2023)

Sabrina Velasco Kris French Bradley Law Caragh G. Threlfall

Abstract Bat boxes are often installed as substitute habitats to offset the loss of large, hollow‐bearing trees. However, emerging evidence suggests that they are failing to achieve intended conservation outcomes as they only support generalist species. Despite these concerns, the effect of bat boxes on the dynamics of bat communities remains understudied. We assessed the bat community in reserves where bat boxes had been installed in comparison with reserves where they had not using ultrasonic surveys in 16 small bushland reserves throughout Sydney, Australia. Reserves containing bat boxes and those without had comparable species diversity and composition; however, the activity of the dominant species, Gould's wattled bat ( Chalinolobus gouldii ), was significantly higher at sites with bat boxes. Species that commonly forage in open vegetation, including C. gouldii , were significantly positively associated with sites that had bat boxes. Occupation of boxes by bats was not recorded in the study due to limited information on their locations, so further research is required to understand the direct effects of boxes and the bats that occupy them on the bat community. If bat boxes continue to be recommended as a biodiversity offset, a greater understanding of the potential impact they have on altered competitive relationships and community dynamics is essential.

10.1111/aec.13435

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Ecological processes in urban landscapes: mechanisms influencing the distribution and activity of insectivorous bats

Ecography (2011)

Caragh G. Threlfall Bradley Law Trent D. Penman Peter B. Banks

Urbanisation affects indigenous fauna in many ways; some species persist and even increase in urban areas, whereas others are lost. The causative mechanisms determining changes in distributions and community structure remain elusive. We investigated three hypothesized mechanisms, which influence success or failure of the insectivorous bat assemblage across the urban landscape of Sydney, Australia; landscape heterogeneity (diversity of land uses), productivity (as indexed by landscape geology) and trait diversity. We present data on species richness and activity (bat passes per night) collected systematically using ultrasonic bat detectors from randomly selected landscapes (each 25km ). Landscapes were categorized into classes including 'urban', 'suburban' and 'vegetated', where suburban sites were additionally stratified based on geology, as a proxy for productivity. Four landscape elements were sampled within each landscape, including remnant bushland (>2ha), riparian areas, open space/parkland and residential/built space. We found that there was significantly greater bat activity and more species of bat in areas on fertile shale geologies (p<0.05), supporting the productivity, rather than the heterogeneity hypothesis. Within landscapes, there was no significant effect of the landscape element sampled, although bushland and riparian sites recorded greater bat activity than open space or backyard sites. Using general linear mixed models we found bat activity and species richness were sensitive to landscape geology and increasing housing density at a landscape scale. Using an RLQ analysis a significant relationship was found between these variables and species traits in structuring the community present (p<0.01). Specifically, open-adapted bats were associated with areas of greater housing density, while clutter-adapted bats were uncommon in urban areas and more associated with greater amounts of bushland in the landscape. Overall we found greater support for the productivity and traits hypotheses, rather than the heterogeneity hypothesis. The degree of urbanisation and amount of bushland remaining, in combination with landscape geology, influenced bat activity and mediated the trait response. Our findings reflect global trends of species diversity and abundance in urban landscapes, suggesting that processes affecting bat species distribution in urban ecosystems may be predictable at a landscape scale. © 2011 The Authors. 2

Insectivore

10.1111/j.1600-0587.2010.06939.x

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Citations (109)

The distinct ecological and social roles that wild spaces play in urban ecosystems

Urban forestry & urban greening (2017)

Caragh G. Threlfall Dave Kendal

Urban ecosystem

10.1016/j.ufug.2017.05.012

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Bee-friendly community gardens: Impact of environmental variables on the richness and abundance of exotic and native bees

Urban Ecosystems (2016)

James C. Makinson Caragh G. Threlfall Tanya Latty

Urban ecology

10.1007/s11252-016-0607-4

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A Research Agenda for Urban Biodiversity in the Global Extinction Crisis

BioScience (2020)

Sonja Knapp Myla F. J. Aronson Ela Sita Carpenter Adriana Herrera-Montes Kirsten Jung

Abstract Rapid urbanization and the global loss of biodiversity necessitate the development of a research agenda that addresses knowledge gaps in urban ecology that will inform policy, management, and conservation. To advance this goal, we present six topics to pursue in urban biodiversity research: the socioeconomic and social–ecological drivers of biodiversity loss versus gain of biodiversity; the response of biodiversity to technological change; biodiversity–ecosystem service relationships; urban areas as refugia for biodiversity; spatiotemporal dynamics of species, community changes, and underlying processes; and ecological networks. We discuss overarching considerations and offer a set of questions to inspire and support urban biodiversity research. In parallel, we advocate for communication and collaboration across many fields and disciplines in order to build capacity for urban biodiversity research, education, and practice. Taken together we note that urban areas will play an important role in addressing the global extinction crisis.

Extinction (optical mineralogy)

Urban ecology

Urban ecosystem

Measurement of biodiversity

10.1093/biosci/biaa141

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Citations (99)

Soil Carbon and Carbon/Nitrogen Ratio Change under Tree Canopy, Tall Grass, and Turf Grass Areas of Urban Green Space

Journal of Environmental Quality (2015)

Stephen J. Livesley Alessandro Ossola Caragh G. Threlfall Amy K. Hahs Nicholas Williams

Soils in urban green spaces are an important carbon (C) store, but urban soils with a high carbon to nitrogen (C/N) ratio can also buffer N eutrophication from fertilizer use or atmospheric deposition. The influence of vegetation management practices on soil C cycling and C/N ratios in urban green spaces is largely unknown. In 2013, we collected replicate ( = 3) soil samples from tree canopy, tall grass, and short turf grass areas ( = 3) at four random plot locations ( = 4) established in 13 golf courses ( = 13). At each sample point, soil was separated into 0- to 0.1-, 0.1- to 0.2-, and 0.2- to 0.3-m depths (total = 1404). Linear mixed models investigated the relationships between soil properties, vegetation attributes, and green space age. Tree canopy soil was less compacted (1.07 g cm) than grassy areas (1.32 g cm). Similarly, tree canopy soil had mean C/N ratios of 17.2, as compared with between 14.2 and 15.3 in grassy areas. Soil properties in tree canopy areas were best explained by tree basal area and understory vegetation volume. Soil C/N increased with increasing understory vegetation, and the difference in soil C/N between tree canopy and short turf grass areas increased over time. The soil properties in tree canopy areas of urban green space mean they can increasingly buffer the localized use of N fertilizers and atmospheric N deposition. Managers of urban green spaces concerned about N pollution of groundwater and waterways could consider planting trees in suitable topographic locations and promoting understory vegetation and surface litter accumulation.

Understory

Tree canopy

Soil carbon

10.2134/jeq2015.03.0121

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Citations (81)

Managing Urban Landscapes for Biodiversity Conservation and Human Health

Dave Kendal Emily J. Flies Pauline Marsh Philip Jones Caragh G. Threlfall

Key Findings A diverse range of actors are involved in created policy and management of green spaces (researchers, practitioners and community groups) in the greater Hobart region Leadership usually occurs at local council level The presence of infrastructure in green spaces can encourage use by people, but reduce biodiversity conservation for wildlife The greatest barriers for green space management and engagement were due to lack of resources (especially in smaller councils), language barriers and ‘biophobia’ (fear of nature) Enablers for improving green space management include public education and community engagement Better connections are needed between different councils in the greater Hobart region, and between practitioners and researchers

Green infrastructure

Community Engagement

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Urban ecology: theory, policy and practice in New South Wales, Australia

Peter R. Davies Linda Corkery David A. Nipperess Francesca van den Berg Cyrielle Joei

Urban ecology

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Global urban environmental change drives adaptation in white clover

Science (2022)

James S. Santangelo Rob W. Ness Beata Cohan Connor R. Fitzpatrick Simon G. Innes

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.

Environmental change

10.1126/science.abk0989

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Citations (110)