Interactive effects of rising temperatures and urbanisation on birds across different climate zones: A mechanistic perspective. Issue 9 (13th March 2023)

• Record Type: Journal Article
• Authors: Sumasgutner, Petra; Cunningham, Susan J.; Hegemann, Arne; Amar, Arjun; Watson, Hannah; Nilsson, Johan F.; Andersson, Martin N.; Isaksson, Caroline
• Is Part Of: Global change biology. Volume 29:Issue 9(2023)
• Page Start: 2399
• Page End: 2420
• Publication Date: 2023-03-13
• Subjects: Anthropocene -- anthropogenic resources -- behavioural plasticity -- human‐induced rapid environmental change (HIREC) -- immune system -- pollution -- redox system -- urban heat island effect (UHI); Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.16645
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Climate change and urbanisation are among the most pervasive and rapidly growing threats to biodiversity worldwide. However, their impacts are usually considered in isolation, and interactions are rarely examined. Predicting species' responses to the combined effects of climate change and urbanisation, therefore, represents a pressing challenge in global change biology. Birds are important model taxa for exploring the impacts of both climate change and urbanisation, and their behaviour and physiology have been well studied in urban and non‐urban systems. This understanding should allow interactive effects of rising temperatures and urbanisation to be inferred, yet considerations of these interactions are almost entirely lacking from empirical research. Here, we synthesise our current understanding of the potential mechanisms that could affect how species respond to the combined effects of rising temperatures and urbanisation, with a focus on avian taxa. We discuss potential interactive effects to motivate future in‐depth research on this critically important, yet overlooked, aspect of global change biology. Increased temperatures are a pronounced consequence of both urbanisation (through the urban heat island effect) and climate change. The biological impact of this warming in urban and non‐urban systems will likely differ in magnitude and direction when interacting with other factors that typically vary between these habitats, such as resource availability (e.g. water, food and microsites) and pollution levels. Furthermore, the nature of such interactions may differ for cities situated in different climate types, for example, tropical, arid, temperate, continental and polar. Within this article, we highlight the potential for interactive effects of climate and urban drivers on the mechanistic responses of birds, identify knowledge gaps and propose promising future research avenues. A deeper understanding of the behavioural and physiological mechanisms mediating species' responses to urbanisation and rising temperatures will provide novel insights into ecology and evolution under global change and may help better predict future population responses. Abstract : Resource availability/reliability (blue) and quality (purple) differ between urban and non‐urban areas and will interact with rising temperatures to influence the magnitude of biological impacts of climate change. Specifically, the urban environment could both buffer and exacerbate the biological impacts of rising temperatures. Greater water availability/reliability in cities buffers thermoregulatory costs, while poorer urban water quality exacerbates warming‐related increases in disease risk and pollutants may reduce thermoregulatory capacity. Greater food availability and artificial light at night may buffer foraging‐thermoregulation trade‐offs in cities, while warming‐related declines in food quality (e.g. carotenoids) are exacerbated in cities. Urban nest‐ and roost sites are poorly thermally buffered, hence of lower quality, than non‐urban sites, while more shade is available in cities, especially in arid regions. Finally, the effects of rising temperatures are likely exacerbated by air pollution and vice versa, with impacts on the redox system and immune system. The UHI effect under climate change will likely continue to lead to relaxed thermoregulatory costs in temperate, continental and polar cities during winter, while exacerbating thermoregulatory costs in summer and in tropical cities compared with non‐urban environments. Cities in arid zones often have a reversed heat island effect, buffering thermal costs.