Urban ecology

Urban Ecology
This is the urban century. For the first time in human history the majority of people live in urban areas, which are growing proportionally faster than any other form of land cover. It is vital to understand the ecology of these areas for two main reasons. First, they are playing an increasing role in landscapes, both directly by supplanting other land covers, and indirectly as the ultimate source of most of the anthropogenic pressures being placed on the planet. Second, despite growing evidence of the importance of these interactions for health and well-being, people are becoming increasingly isolated from nature, and for many of them urban environments are the principal or only arena for such contact that they do have.

(i) Night-time lighting
The global and regional distribution of artificial night-time lights has frequently been used as an indicator of the urban transformation. However, more directly, such imagery also captures the spread of an evolutionarily unprecedented environmental change, the disruption across large areas of the Earth of the spatial and temporal (daily, seasonal, annual) patterns and cycles of light and dark that have previously remained approximately constant as a consequence of the Earth’s rotation, tilt of axis and orbital motion. This has raised ecological concerns, given that light and dark provide critical resources and environmental conditions for organisms and play key roles in their physiology, growth, behaviour and reproductive success, including providing cues used to entrain internal biological clocks to local time. Indeed, the potential has long been recognised that light pollution of the night may have profound consequences for the structure and functioning of populations, communities and ecosystems, and both science and policy documents regularly highlight this. Nonetheless, to date studies have focussed on obviously catastrophic effects on particular species, such as bird strikes on lighthouses and other tall lighted structures and the disorientation of hatchling sea turtles by beach-side lights. Empirical studies of the likely more pervasive and subtle effects on populations and communities remain wanting. We are working to bring about a step change in understanding of the population and community effects of night-time light pollution

[Key ref.: Bennie, J., Davies, T.W., Cruse, D., Inger, R. & Gaston, K.J. 2015. Cascading effects of artificial light at night: resource-mediated control of herbivores in a grassland ecosystem. Phil. Trans. R. Soc. B 370, 20140131; Bennie, J., Davies, T., Duffy, J., Inger, R. & Gaston, K.J. 2014. Contrasting trends in light pollution across Europe. Scientific Reports 4, 3789; Gaston, K.J., Bennie, J., Davies, T.W. & Hopkins, J. 2013. The ecological impacts of nighttime light pollution: a mechanistic appraisal. Biological Reviews 88, 912-27]

(ii) Urban development
There is a growing appreciation of the benefits that can be obtained from urban areas, particularly from the green and blue infrastructure (which can be very extensive), rather than simply how to mitigate the negative influences of those areas. We are interested in quantifying the provision of biodiversity, ecosystem goods and services in urban areas, the spatial variation in this provision, and particularly how this provision can most effectively be improved.

[Key ref.: Davies, Z.G., Edmondson, J.L., Leake, J.R. & Gaston, K.J.∗2011. Mapping an urban ecosystem service: quantifying above-ground carbon storage at a city-wide scale. J. Appl. Ecol. 48, 1125-34; Edmondson, J.L., Davies, Z.G., McHugh, N., Gaston, K.J. & Leake, J.R. 2012. Organic carbon hidden in urban ecosystems. Sci. Rep. 2, 963; Gaston, K.J., Ávila-Jiménez, M.L. & Edmondson, J.L. 2013. Managing urban ecosystems for goods and services. J. Appl. Ecol. 50, 830-40]

(iii) Colonisation of urban areas
Alongside the extinctions induced by urbanisation, an increasing number of native species are colonising urban environments for the first time. We are interested in how such colonisation processes take place, and the extent to which urban populations of species genetically diverge from non-urban populations. In particular, we have been using the European blackbird Turdus merula as a model study system.

[Key ref.: Evans, K.L., Gaston, K.J., Frantz, A.C., Simeoni, M., Sharp, S.P., McGowan, A., Dawson, D.A., Walasz, K., Partecke, J., Burke, T. & Hatchwell, B.J. 2009. Independent colonization of multiple urban centres by a formerly forest bird specialist. Proc. R. Soc. B 276, 2403-10; Evans, K.L., Hatchwell, B.J., Parnell, M. & Gaston, K.J. 2010. A conceptual framework for the colonisation of urban areas: the blackbird Turdus merula as a case study. Biol. Rev. 85, 643-67; Mueller, J.C., Partecke, J., Hatchwell, B.J, Gaston, K.J. & Evans, K.L. 2013. Candidate gene polymorphisms for behavioural adaptations during urbanization in blackbirds. Molecular Ecol. 22, 3629-37]

(iv) Human-nature interactions
People in urban areas gain a diversity of important health and well-being benefits from their interactions of nature.

We are interested in the benefits that people gain from contact with nature in urban environments, and particularly from biodiversity. There is ample evidence that green and blue infrastructure are good for multiple dimensions of health and well-being, the challenge is to unpick what components of that infrastructure are of greatest importance.

[Key ref.: Dallimer, M., Irvine, K.N., Skinner, A.M.J., Davies, Z.G., Rouquette, J.R., Armsworth, P.R., Maltby, L., Warren, P.H., Gaston, K.J. 2012. Biodiversity and the feel-good factor: understanding associations between self-reported human well-being and species richness. BioScience 62, 46-55; Shanahan, D.F., Bush, R., Lin, B.B., Gaston, K.J., Barber, L., Dean, J., Fuller, R.A. 2015. Towards improved public health outcomes from urban nature. Am. J. Public Health, in press; Shanahan, D.F., Fuller, R.F., Bush, R., Lin, B.B. & Gaston, K.J. 2015. The health benefits of urban nature: how much do we need? BioScience, in press.]

(v) Domestic gardens
Domestic gardens comprise a high proportion of the green space of urban areas in many developed countries. We have conducted some of the most extensive and intensive studies of the importance of such gardens for biodiversity and ecosystem services.

[Key ref.: Cannon, A.R., Chamberlain, D.E., Toms, M.P., Hatchwell, B.J. & Gaston, K.J. 2005. Trends in the use of private gardens by wild birds in Great Britain 1995–2002. J. Appl. Ecol. 42, 659-71; Davies, Z.G., Fuller, R.A., Loram, A., Irvine, K.N., Sims, V. & Gaston, K.J. 2009. A national scale inventory of resource provision for biodiversity within domestic gardens. Biol. Conserv. 142, 761-71; Smith, R.M., Thompson, K., Warren, P.H. & Gaston, K.J. 2010. Urban domestic gardens (XIII): composition of the bryophyte and lichen floras, and determinants of species richness. Biol. Conserv. 143, 873-82]