KEVIN J GASTON

McHugh, N., Edmondson, J.L., Gaston, K.J., Leake, J.R. & O’Sullivan, O.S. (2015) Modelling short-rotation coppice and tree planting for urban carbon management – a city-wide analysis. Journal of Applied Ecology 52, 1237–1245.

1. The capacity of urban areas to deliver provisioning ecosystem services is commonly overlooked and underutilized. Urban populations have globally increased five-fold since 1950, they disproportionately consume ecosystem services and contribute to carbon emissions, highlighting the need to increase urban sustainability and reduce environmental impacts of urban dwellers. Here we investigated the potential for increasing carbon sequestration, and biomass fuel production, by planting trees and short-rotation coppice (SRC) respectively, in a mid-sized UK city as a contribution to meeting national commitments to reduce CO₂ emissions.

2. Iterative GIS models were developed using high resolution spatial data. The models were applied to patches of public and privately owned urban greenspace suitable for planting trees and SRC, across the 73 km² area of the city of Leicester. We modelled tree planting with a species-mix based on the existing tree populations, and SRC with willow and poplar to calculate biomass production in new trees, and carbon sequestration into harvested biomass over 25 years.

3. An area of 11 km² comprising 15% of the city, met criteria for tree planting and had the potential over 25 years to sequester 4200 tonnes of carbon above-ground. Of this area, 5.8 km² also met criteria for SRC planting and over the same period this could yield 71 800 tonnes of carbon in harvested biomass.

4. The harvested biomass could supply energy to over 1566 domestic homes or 30 municipal buildings, resulting in avoided carbon emissions of 29 236 tonnes of carbon over 25 years when compared to heating by natural gas. Together with the net carbon sequestration into trees, a total reduction of 33 419 tonnes of carbon in the atmosphere could be achieved in 25 years by combined SRC and tree planting across the city.

5. Synthesis and applications. We demonstrate that urban greenspaces in a typical UK city are underutilized for provisioning ecosystem services by trees and especially short-rotation coppice (SRC), which has high biomass production potential. For urban greenspace management we recommend that planting SRC in urban areas can contribute to reducing food–fuel conflicts on agricultural land and produce renewable energy sources close to centres of population and demand.

Bonnington, C., Gaston, K.J. & Evans, K.L. (2015) Ecological traps and behavioural adjustments of urban songbirds to fine-scale spatial variation in predator activity. Animal Conservation, DOI: 10.1111/acv.12206.

The influence of predators on bird populations is controversial and poorly understood, especially in urban areas where predator densities can be particularly high. We assessed if fine-scale spatial variation in predator activity and proximity have direct and indirect effects on urban songbird distributions and breeding success, by testing the hypotheses that (1) songbirds that are sensitive to nest predation select territories with reduced activity of nest predators; (2) blackbird Turdus merula, a species that experiences high nest predation rates, lays smaller clutches in territories located in areas with higher numbers of nest predators as predicted by Skutch’s hypothesis; (3) songbirds that are sensitive to nest predation have higher nest predation rates in areas with greater predator activity. We tested these hypotheses using two sites in urban Sheffield, UK, and focus on nest predatory corvids and grey squirrels Sciurus carolinensis. We found no evidence that songbirds that are most sensitive to nest predation adjust their territory location in response to fine-scale spatial variation in predator distributions. It thus seems unlikely that urban predators are indirectly regulating urban bird population size by restricting habitat availability. Blackbirds did not vary their clutch size in response to predator distributions. These findings generate the potential for an ecological trap in which prey species fail to avoid areas with the highest concentrations of nest predators, or to exhibit behavioural adjustments to reduce the risk of nest predation at such sites. We find some evidence for such ecological traps as, while fine-scale variation in grey squirrel occurrence and activity were not associated with nest predation rates, nests located in closer proximity to corvids and in areas with higher indices of corvid activity experienced slightly higher nest predation rates.

Shanahan, D.F., Fuller, R.A., Bush, R., Lin, B.B. & Gaston, K.J. (2015) The Health Benefits of Urban Nature: How Much Do We Need? BioScience 65 (5), 476-485.

Over 30 years of research has shown that urban nature is a promising tool for enhancing the physical, psychological, and social well-being of the world’s growing urban population. However, little is known about the type and amount of nature people require in order to receive different health benefits, preventing the development of recommendations for minimum levels of exposure and targeted city planning guidelines for public health outcomes. Dose–response modelling, when a dose of nature is modeled against a health response, could provide a key method for addressing this knowledge gap. In this overview, we explore how “nature dose” and health response have been conceptualized and examine the evidence for different shapes of dose–response curves. We highlight the crucial need to move beyond simplistic measures of nature dose to understand how urban nature can be manipulated to enhance human health.

Gómez P., Bennie J., Gaston K.J. & Buckling A. (2015) The Impact of Resource Availability on Bacterial Resistance to Phages in Soil. PLoS ONE 10(4): e0123752.

Resource availability can affect the coevolutionary dynamics between host and parasites, shaping communities and hence ecosystem function. A key finding from theoretical and in vitro studies is that host resistance evolves to greater levels with increased resources, but the relevance to natural communities is less clear. We took two complementary approaches to investigate the effect of resource availability on the evolution of bacterial resistance to phages in soil. First, we measured the resistance and infectivity of natural communities of soil bacteria and phage in the presence and absence of nutrient-providing plants. Second, we followed the real-time coevolution between defined bacteria and phage populations with resource availability manipulated by the addition or not of an artificial plant root exudate. Increased resource availability resulted in increases in bacterial resistance to phages, but without a concomitant increase in phage infectivity. These results suggest that phages may have a reduced impact on the control of bacterial densities and community composition in stable, high resource environments.

Porcelli, D., Butlin, R.K., Gaston, K.J., Joly, D. & Snook, R.R. (2015) The environmental genomics of metazoan thermal adaptation. Heredity 114, 502–514.

Continued and accelerating change in the thermal environment places an ever-greater priority on understanding how organisms are going to respond. The paradigm of ‘move, adapt or die’, regarding ways in which organisms can respond to environmental stressors, stimulates intense efforts to predict the future of biodiversity. Assuming that extinction is an unpalatable outcome, researchers have focussed attention on how organisms can shift in their distribution to stay in the same thermal conditions or can stay in the same place by adapting to a changing thermal environment. How likely these respective outcomes might be depends on the answer to a fundamental evolutionary question, namely what genetic changes underpin adaptation to the thermal environment. The increasing access to and decreasing costs of next-generation sequencing (NGS) technologies, which can be applied to both model and non-model systems, provide a much-needed tool for understanding thermal adaptation. Here we consider broadly what is already known from non-NGS studies about thermal adaptation, then discuss the benefits and challenges of different NGS methodologies to add to this knowledge base. We then review published NGS genomics and transcriptomics studies of thermal adaptation to heat stress in metazoans and compare these results with previous non-NGS patterns. We conclude by summarising emerging patterns of genetic response and discussing future directions using these increasingly common techniques.

Dallimer, M., Davies, Z.G., Diaz-Porras, D.F., Irvine, K.N., Maltby, L., Warren, P.H., Armsworth, P.R. & Gaston, K.J. (2015) Historical influences on the current provision of multiple ecosystem services. Global Environmental Change 31, 307-317.

Ecosystem service provision varies temporally in response to natural and human-induced factors, yet research in this field is dominated by analyses that ignore the time-lags and feedbacks that occur within socio-ecological systems. The implications of this have been unstudied, but are central to understanding how service delivery will alter due to future land-use/cover change. Urban areas are expanding faster than any other land-use, making cities ideal study systems for examining such legacy effects. We assess the extent to which present-day provision of a suite of eight ecosystem services, quantified using field-gathered data, is explained by current and historical (stretching back 150 years) landcover. Five services (above-ground carbon density, recreational use, bird species richness, bird density, and a metric of recreation experience quality (continuity with the past) were more strongly determined by past landcover. Time-lags ranged from 20 (bird species richness and density) to over 100 years (above-ground carbon density). Historical landcover, therefore, can have a strong influence on current service provision. By ignoring such time-lags, we risk drawing incorrect conclusions regarding how the distribution and quality of some ecosystem services may alter in response to land-use/cover change. Although such a finding adds to the complexity of predicting future scenarios, ecologists may find that they can link the biodiversity conservation agenda to the preservation of cultural heritage, and that certain courses of action provide win-win outcomes across multiple environmental and cultural goods.

Mitchell, M.G.E., Suarez-Castro, A.F., Martinez-Harms, M., Maron, M., McAlpine, C., Gaston, K.J., Johansen, K. & Rhodes, J.R. (2015) Reframing landscape fragmentation’s effects on ecosystem services. Trends in Ecology and Evolution 30(4), 190-198.

Landscape structure and fragmentation have important effects on ecosystem services, with a common assumption being that fragmentation reduces service provision. This is based on fragmentation’s expected effects on ecosystem service supply, but ignores how fragmentation influences the flow of services to people. Here we develop a new conceptual framework that explicitly considers the links between landscape fragmentation, the supply of services, and the flow of services to people. We argue that fragmentation’s effects on ecosystem service flow can be positive or negative, and use our framework to construct testable hypotheses about the effects of fragmentation on final ecosystem service provision. Empirical efforts to apply and test this framework are critical to improving landscape management for multiple ecosystem services.