Alien abundances dominate

Blackburn, T.M. & Gaston, K.J. 2018. Abundance, biomass and energy use of native and alien breeding birds in Britain. Biological Invasions 20, 3563-3573. [Photo: T.M. Blackburn]

We quantify the contribution of alien species to the total breeding population numbers, biomass and energy use of an entire taxonomic assemblage at a large spatial scale, using data on British birds from 1997 and 2013. A total of 216 native and 16 alien bird species were recorded as breeding in Great Britain across the two census years. Only 2.8-3.7% of British breeding bird individuals were alien, but alien species co-opted 11.9-13.8% of the energy used by the assemblage, and contributed 19.1-21.1% of assemblage biomass. Neither the population sizes nor biomasses of native and alien species differed, on average, in either census, but alien species biomass is higher than native species biomass for a given population size. Species richness underestimates the potential effects of alien bird species in Britain, which have disproportionately high overall biomass and population energy use. The main driver of these effects is the ring-necked pheasant (Phasianus colchicus), which comprised 74–81% of alien biomass, yet the breeding population of this species is still only a small fraction of the estimated 35 million birds released in the UK in autumn. The biomass of this release exceeds that of the entire breeding avifauna, and suggests that the pheasant should have an important role in structuring the communities in which it is embedded.


Daylength changes community dynamics

Kehoe, R., Cruse, D., Sanders, D., Gaston, K.J. & van Veen, F.J.F. 2018. Shifting daylength regimes associated with range shifts alter aphid-parasitoid community dynamics. Ecology and Evolution, online early. 

1. With climate change leading to poleward range expansion of species, populations are exposed to new daylength regimes along latitudinal gradients. Daylength is a major factor affecting insect life cycles and activity patterns, so a range shift leading to new daylength regimes is likely to affect population dynamics and species interactions; however, the impact of daylength in isolation on ecological communities has not been studied so far.

2. Here, we tested for the direct and indirect effects of two different daylengths on the dynamics of experimental multitrophic insect communities. We compared the community dynamics under “southern” summer conditions of 14.5‐hr daylight to “northern” summer conditions of 22‐hr daylight.

3. We show that food web dynamics indeed respond to daylength with one aphid species (Acyrthosiphon pisum) reaching much lower population sizes at the northern daylength regime compared to under southern conditions. In contrast, in the same communities, another aphid species (Megoura viciae) reached higher population densities under northern conditions.

4. This effect at the aphid level was driven by an indirect effect of daylength causing a change in competitive interaction strengths, with the different aphid species being more competitive at different daylength regimes. Additionally, increasing daylength also increased growth rates in M. viciae making it more competitive under summer long days. As such, the shift in daylength affected aphid population sizes by both direct and indirect effects, propagating through species interactions. However, contrary to expectations, parasitoids were not affected by daylength.

5. Our results demonstrate that range expansion of whole communities due to climate change can indeed change interaction strengths between species within ecological communities with consequences for community dynamics. This study provides the first evidence of daylength affecting community dynamics, which could not be predicted from studying single species separately.

Artificial nighttime light drives evolution

Hopkins, G.R., Gaston, K.J., Marcel E. Visser, M.E., Elgar, M.A. & Jones, T.M. 2018. Artificial light at night as a driver of evolutionary change across the urban-rural landscapes. Frontiers in Ecology and the Environment, online early. 

Light is fundamental to biological systems, affecting the daily rhythms of bacteria, plants, and animals. Artificial light at night (ALAN), a ubiquitous feature of urbanization, interferes with these rhythms and has the potential to exert strong selection pressures on organisms living in urban environments. ALAN also fragments landscapes, altering the movement of animals into and out of artificially lit habitats. Although research has documented phenotypic and genetic differentiation between urban and rural organisms, ALAN has rarely been considered as a driver of evolution. We argue that the fundamental importance of light to biological systems, and the capacity for ALAN to influence multiple processes contributing to evolution, makes this an important driver of evolutionary change, one with the potential to explain broad patterns of population differentiation across urban–rural landscapes. Integrating ALAN’s evolutionary potential into urban ecology is a targeted and powerful approach to understanding the capacity for life to adapt to an increasingly urbanized world.

When a little light goes a long way

Sanders, D., Kehoe, R., Cruse, D., van Veen, F.J.F. & Gaston, K.J. 2018. Low levels of artificial light at night change food web dynamics. Current Biology, in press. 

Artificial light has transformed the nighttime environment of large areas of the earth, with 88% of Europe and almost 50% of the United States experiencing light-polluted night skies. The consequences for ecosystems range from exposure to high light intensities in the vicinity of direct light sources to the very widespread but lower lighting levels further away. While it is known that species exhibit a range of physiological and behavioural responses to artificial nighttime lighting, there is a need to gain a mechanistic understanding of whole ecological community impacts, especially to different light intensities. Using a mesocosm field experiment with insect communities, we determined the impact of intensities of artificial light ranging from 0.1 to 100 lux on different trophic levels and interactions between species. Strikingly, we found the strongest impact at low levels of artificial lighting (0.1 to 5 lux), which led to a 1.8 times overall reduction in aphid densities. Mechanistically, artificial light at night increased the efficiency of parasitoid wasps in attacking aphids, with twice the parasitism rate under low light levels compared to unlit controls. However at higher light levels, parasitoid wasps spent longer away from the aphid host plants, diminishing this increased efficiency. Therefore aphids reached higher densities under increased light intensity as compared to low levels of lighting where they were limited by higher parasitoid efficiency. Our study highlights the importance of different intensities of artificial light in driving the strength of species interactions and ecosystem functions.


Gaps in cactus conservation

Goettsch, B.,, Durán, A.P. & Gaston, K.J. 2018. Global gap analysis of cactus species and priority sites for their conservation. Conservation Biology, in press. 

Determining how much biodiversity is captured by protected areas (PAs) can play a key role in meeting country commitments to international agreements such as the Convention on Biological Diversity, while analysing gaps in species coverage by PAs can greatly contribute to better locating new PAs and conserving species. It is troublesome, however, that regardless of their importance, global gap analyses have only been conducted for major taxonomic groups of vertebrates, such as amphibians, birds and mammals. Here we present the first global gap analysis for a complete plant group, the highly threatened Cactaceae. Using geographic distribution data of 1438 cactus species we assessed how well the current PA network represents them. Additionally, we performed systematic conservation planning analyses to identify priority conservation areas for cactus species that met and failed to meet conservation targets accounting for their conservation status. We found a total of 261 species with no coverage by PAs. Our results show that a greater percentage of cacti species (18%) are lacking such protection than for mammals (9.7%) and birds (5.6%), and there is also a greater percentage of threatened cacti species (32%) outside protected areas than for amphibians (26.5%), birds (19.9%) and mammals (16%). We found that the top 17% of the landscape that best captures covered species represents on average 52.9% of species ranges and half of its extent is distributed across 14 PAs. The priority areas for the gap and the unprotected ranges of partially‐gap species captured on average 75.2% of their ranges, of which 100 were threatened gap species. These findings, paired with knowledge of the threats affecting species, give important information better to plan conservation action for cacti and also support the importance of assessing the representation of major groups such as plants in determining the real performance of the current PA network.


Drones diagnose coral health

Parsons, M., Bratanov, D., Gaston, K.J. & Gonzalez, F. 2018. UAVs, hyperspectral remote sensing and machine learning revolutionizing reef monitoring. Sensors 18, 2026. 

Recent advances in unmanned aerial system (UAS) sensed imagery, sensor quality/size, and geospatial image processing can enable UASs to rapidly and continually monitor coral reefs, to determine the type of coral and signs of coral bleaching. This paper describes an unmanned aerial vehicle (UAV) remote sensing methodology to increase the efficiency and accuracy of existing surveillance practices. The methodology uses a UAV integrated with advanced digital hyperspectral, ultra HD colour (RGB) sensors, and machine learning algorithms. This paper describes the combination of airborne RGB and hyperspectral imagery with in-water survey data of several types in-water survey of coral under diverse levels of bleaching. The paper also describes the technology used, the sensors, the UAS, the flight operations, the processing workflow of the datasets, the methods for combining multiple airborne and in-water datasets, and finally presents relevant results of material classification. The development of the methodology for the collection and analysis of airborne hyperspectral and RGB imagery would provide coral reef researchers, other scientists, and UAV practitioners with reliable data collection protocols and faster processing techniques to achieve remote sensing objectives.

Health benefits of nature relatedness

Dean, J.H., Shanahan, D.F., Bush, R., Gaston, K.J., Lin, B.B., Barber, E., Franco, L. & Fuller, R.A. 2018. Is nature relatedness associated with better mental and physical health? International Journal of Environmental Research and Public Health 15, 1371. 

Nature relatedness is a psychological characteristic with the potential to drive interaction with nature and influence well-being. We surveyed 1538 people in Brisbane, Australia to investigate how nature relatedness varies among socio-demographic groups. We determined whether people with higher nature relatedness reported fewer symptoms of depression, anxiety, stress and better overall health, controlling for potentially confounding socio-demographic and health-related variables. Overall nature relatedness was higher in older people, females, those without children living at home, not working, and people speaking English at home. Aspects of nature relatedness reflecting enjoyment of nature were consistently associated with reduced ill health, consistent with widespread evidence of the health and well-being benefits of experiencing nature. In contrast, aspects of nature relatedness reflecting self-identification with nature, and a conservation worldview, were associated with increased depression, anxiety or stress, after accounting for potential confounding factors. Detailed investigation of causal pathways among nature relatedness, socio-demographic factors and health is warranted, with particular focus on the relationship between stress and nature orientation.

Visualising the urban green

Anderson, K., Hancock, S. Casalegno, S., Griffiths, A., Griffiths, D., Sargent, F., McCallum, J., Cox, D.T.C. & Gaston, K.J. 2018. Visualising the urban green volume: Exploring LiDAR voxels with tangible technologies and virtual models. Landscape and Urban Planning 178, 248-260. 

The distribution of vegetation within urban zones is well understood to be important for delivery of a range of ecosystem services. While urban planners and human geographers are conversant with methodologies for describing and exploring the volumetric nature of built spaces there is less research that has developed imaginative ways of visualising the complex spatial and volumetric structure of urban vegetation from the treetops to the ground. Using waveform LiDAR data to measure the three-dimensional nature of the urban greenspace, we explore different ways of virtually, and tangibly engaging with volumetric models describing the 3D distribution of urban vegetation. Using waveform LiDAR data processed into voxels (volumetric pixels) and experimenting with a variety of creative approaches to visualise the volumetric nature of the data, we describe the development of new methods for mapping the urban green volume, using a combination of Geographic Information Systems (GIS), Minecraft, 3D printing and Computer Numerical Control (CNC) milling processes. We demonstrate how such methodologies can be used to reveal and explore the complex nature of the urban green volume. We also describe the outcome of using these models to engage diverse audiences with the volumetric data. We explain how the products could be used readily by a range of urban researchers and stakeholders: from town and city councils, to architects and ecologists.

Research priorities for protected areas

Dudley, N., Hockings, M., Stolton, S., Amend, T., Badola, R., Bianco, M., Chetri, N., Cook, C., Day, J.C., Dearden, P., Edwards, M., Ferraro, P., Foden, W., Gambino, R., Gaston, K.J., Hayward, N., Hickey, V., Irving, J., Jeffries, B., Karapetyan, A., Kettunen, M., Laestadius, L., Laffoley, D., Lham, D., Lichtenstein, G., Makombo, J., Marshall, N., McGeoch, M., Nguyen, D., Nogué, S., Paxton, M., Rao, M., Reichelt, R., Rivas, J., Roux, D., Rutte, C., Schreckenberg, K., Sovinc, A., Sutyrina, S., Utomo, A., Vallauri, D.,, Vedeld, P.O., Verschuuren, B., Waithaka, J., Woodley, S., Wyborn, C. & Zhang, Y. 2018. Priorities for protected area research. Parks 24, 35-50.

A hundred research priorities of critical importance to protected area management were identified by a targeted survey of conservation professionals; half researchers and half practitioners. Respondents were selected to represent a range of disciplines, every continent except Antarctica and roughly equal numbers of men and women. The results analysed thematically and grouped as potential research topics as by both practitioners and researchers. Priority research gaps reveal a high interest to demonstrate the role of protected areas within a broader discussion about sustainable futures and if and how protected areas can address a range of conservation and socio-economic challenges effectively. The paper lists the hundred priorities structured under broad headings of management, ecology, governance and social (including political and economic issues) and helps contribute to setting future research agendas.


‘People and Nature’ launches

So, you have a great idea for a new paper. It looks at some aspect of the interactions between people and nature. It will have some ecological relevance, but may not be a pure ecology paper. It will also have a good bit of material drawn from one or more other disciplines – it could be economics, geography, history, law, literature, medicine, philosophy, politics, psychology, or sociology, to name just a few possibilities. But it is not a mainstream paper for one of those disciplines either. So, where will you submit your latest contribution? You will want a journal that not just considers outputs from this kind of cross/multi/interdisciplinary work, but really values them. You will want one that understands both the importance of your paper being promptly and fairly handled by people who are knowledgeable about the topic, and that takes seriously the challenges that can arise when reviewing work that crosses disciplinary specialisms. You will want one backed by a respected organisation, with a track record of publishing high quality journals.

Welcome to People and Nature – a journal of relational thinking.

The British Ecological Society is launching this new journal in recognition of the rapid growth in inter-, multi-, and transdisciplinary research concerning the relationships between humans and nature. Much of this research addresses issues of vital importance.

We look forward to receiving your submissions.