KEVIN J GASTON

Dallimer, M., Rouquette, J.R., Skinner, A.M.J., Armsworth, P.R., Maltby, L.M., Warren, P.H. & Gaston, K.J. 2012. Contrasting patterns in species richness of birds, butterflies and plants along riparian corridors in an urban landscape. Diversity and Distributions 18, 742-753.

Urbanization is a major driver of global landuse change, substantially modifying patterns of biodiversity. Managing these impacts has become a conservation priority. The creation and maintenance of greenways, such as river corridors, is frequently promoted as a strategy for mitigating habitat fragmentation in urban areas by bringing semi-natural habitat cover into city centres. However, there is little evidence to support this assertion. Here, we examine whether riparian zones maintain semi-natural habitat cover in urban areas and how species richness varies along such zones. We find that multiple transects and taxonomic groups are required to describe species richness responses to urbanization as no single pattern is evident. Although riparian zones are an important component of the mosaic of urban habitats, we find that river corridors do not disproportionately support tree and natural surface cover when compared to non-riverine urban areas.

Gaston, K.J. 2012. The importance of being rare. Nature 487, 46-47.

A commentary on a recent paper by Mi et al. on the differences between common and rare species.

This week’s issue of Nature also picks up on our research on the ecological effects of street lighting.

Our research got a mention on BBC Springwatch!

Coming very soon! The first paper, of what will hopefully be many, from the Ecolight project and on a new and exciting avenue of work for the research group.

Davies, T.W., Bennie, J. & Gaston, K.J. 2012. Street lighting changes the composition of invertebrate communities. Biology Letters, in press.

Cianciaruso, M.V. Silva, I.A., Batalha, M.A., Gaston, K.J. & Petchey O.L. 2012. The influence of fire on phylogenetic and functional structure of woody savannas: moving from species to individuals. Perspectives in Plant Ecology, Evolution and Systematics 14, 205-216.

Fire is a key determinant of tropical savanna structure and functioning. High fire frequencies are expected to assemble closely related species with a restricted range of functional trait values. Here we determined the effect of fire on phylogenetic and functional diversity of woody species and individuals in savanna communities under different fire frequencies. We found phylogenetic signals for one third of the functional traits studied. High numbers of fires simultaneously led to phylogenetic over dispersion and functional clustering when communities were represented by mean trait values with all traits that putatively should be affected or respond to fire. This finding is important, because it shows that the relationship between ecological processes and the phylogenetic structure of communities is not straightforward. Thus, we cannot always assume that close relatives are more similar in their ecological features. However, when considering a different set of traits representing different plant strategies (fire resistance/ avoidance, physiological traits and regeneration traits), the results were not always congruent. When asking how communities are assembled in terms of individuals (not species) the outcome was different from the species-based approach, suggesting that the realised trait values – rather than mean species trait values – have an important role in driving community assembly. Thus, intraspecific trait variability should be taken into account if we want fully to improve our mechanistic understanding of assembly rules in plant communities. [Image: M.V. Cianciaruso]

Armsworth, P.R., Acs, S., Dallimer, M., Gaston, K.J., Hanley, N. & Wilson, P. 2012. The cost of policy simplification in conservation incentive programs. Ecology Letters 15, 406-414.

Incentive payments to private landowners are a commonly employed strategy to conserve biodiversity and enhance the supply of goods and services from ecosystems. To deliver cost-effective improvements in biodiversity, payment schemes must trade-off the inefficiencies that result from over-simplified policies with the administrative burdens of implementing more complex incentive designs. In this paper we examine the effectiveness of different payment schemes using field parameterized, ecological economic models of extensive grazing farms. We focus on profit maximising farm management plans and use bird species as a policy-relevant indicator of biodiversity. Common policy simplifications result in a 49–100% loss in biodiversity benefits depending on the conservation target chosen. Failure to differentiate prices for conservation improvements in space is particularly problematic. Additional implementation costs that accompany more complicated policies are worth bearing even when these constitute a substantial proportion (70% or more) of the payments that would otherwise have been given to farmers.

Evans, K.L., Newton, J., Gaston, K.J., Sharp, S.P., McGowan, A. & Hatchwell, B.J. 2012. Colonisation of urban environments is associated with reduced migratory behaviour, facilitating divergence from ancestral populations. Oikos 121, 634-640.

How individuals colonising novel environments overcome the diverse suite of new selection pressures faced is a fundamental question in ecology and evolution. Urban environments differ markedly from the rural ones that they replace and successful colonisation of urban areas may therefore require local adaptation and phenotypic/genetic divergence from ancestral populations. Such a process would be facilitated by limited dispersal to and from the novel habitat. Here using stable isotopes we provide evidence that urban European blackbird Turdus merula populations tend to be more sedentary than rural ones. The increased sedentary behaviour of urban birds could promote further ecological divergence between rural and urban populations, such as the earlier breeding of urban blackbirds, and in some cases may contribute to their previously documented genetic divergence.

Braschler, B., Chown, S.L. & Gaston, K.J. 2012. The Fynbos and Succulent Karoo biomes do not have exceptional local ant richness. PLoS One 7, e31463.

The Fynbos and Succulent Karoo biomes at the southern tip of Africa are notable for having high regional plant diversity despite relatively low plant productivity. However, whilst local plant diversity varies it remains moderate. Here we show that for ants neither regional nor local richness are exceptional by global standards. It seems unlikely that the mechanisms which have contributed to the development of extraordinarily high regional plant diversity in these biomes have had a strong influence on the ants.