Bottom-up mapping of climate zones

Gardner, A.S., Maclean, I.M.D. & Gaston, K.J. 2020. A new system to classify global climate zones based on plant physiology and using high temporal resolution climate data. Journal of Biogeography, [online early].

Aim: Climate classification systems (CCSs) can be used to predict how species’ distributions might be altered by climate change and to increase the reliability of these estimates is an important goal in biogeographical research. We produce an objective, global climate classification system (CCS) at high temporal resolution based on plant physiology as a robust way to predict how climate change may impact terrestrial biomes.

Location: Global

Taxon: Plantae

Methods: We construct ten climate variables that capture the physiological processes that determine plant distributions and use cluster analysis to present a new global CCS which accounts for variation in these aspects of climate. We use Kappa statistics to compare the distribution of climate zones in a five- and six-cluster CCS constructed using the physiology variables to the popular Köppen-Geiger and Köppen-Trewartha CCSs, respectively, and find good correlation in both cases.

Results: Our CCS highlights ten climate zones for plants. We show that clustering of the physiologically relevant variables reproduces known, present-day patterns of vegetation but also indicates important areas where zone assignment in our physiological CCSs is different to that of the Köppen systems.

Main conclusions: The existing Köppen CCSs do not entirely reflect the physiological processes that determine plant distributions. Predictions of climate-driven changes in plant distributions may thus be unreliable in areas where zone assignment by clustering of physiologically relevant variables is different to that of the Köppen systems. Both the physiological relevance and temporal resolution of climate variables used to construct CCSs should be considered in order to predict reliably how climate change may alter plant distributions and to support an appropriate global response to conserve plant biodiversity for the future.

Pollinators on the verge

Phillips, B.B., Wallace, C., Roberts, B.R., Whitehouse, A.T., Gaston, K.J., Bullock, J.M., Dicks, L.V. & Osborne, J.L. 2020. Enhancing road verges to aid pollinator conservation: a review. Biological Conservation [online early].

Road verges provide habitats that have considerable potential as a tool for pollinator conservation, especially given the significant area of land that they collectively cover. Growing societal interest in managing road verges for pollinators suggests an immediate need for evidence-based management guidance. We used a formal, global literature review to assess evidence for the benefits of road verges for pollinators (as habitats and corridors), the potential negative impacts of roads on pollinators (vehicle-pollinator collisions, pollution, barriers to movement) and how to enhance road verges for pollinators through management. We identified, reviewed and synthesised 140 relevant studies. Overall, the literature review demonstrated that: (i) road verges are often hotspots of flowers and pollinators (well established), (ii) traffic and road pollution can cause mortality and other negative impacts on pollinators (well established), but available evidence suggests that the benefits of road verges to pollinators far outweigh the costs (established but incomplete), and (iii) road verges can be enhanced for pollinators through strategic management (well established). Future research should address the lack of holistic and large-scale understanding of the net effects of road verges on pollinators. We provide management recommendations for enhancing both individual road verges for pollinators (e.g. optimised mowing regimes) and entire road networks (e.g. prioritising enhancement of verges with the greatest capacity to benefit pollinators), and highlight three of the most strongly supported recommendations: (i) creating high quality habitats on new and existing road verges, (ii) reducing mowing frequency to 0–2 cuts/year and (iii) reducing impacts of street lighting.

Nature experiences and life satisfaction

Chang, C-C., Oh, R.R.Y., Nghiem, T.P.L., Zhang, Y., Tan, C.L.Y., Lin, B.B., Gaston, K.J., Fuller, R.A. & Carrasco, L.R. 2020. Life satisfaction linked to the diversity of nature experiences and nature views from the window. Landscape and Urban Planning 202, 103874.

The effects of nature interactions on multiple aspects of human subjective wellbeing are increasingly well understood. Although nature experience has been shown to be positively associated with life satisfaction, it remains unknown whether the diversity of nature experiences contributes to increased life satisfaction and whether the relationship is mediated by a person’s strength of connection with nature. We conducted a national survey in Singapore through online questionnaires (n = 1, 262), where we measured frequency, duration, diversity of nature experiences, and presence or absence of nature views from windows at home and at the workplace. We also measured participants’ strength of connection with nature (how strongly a person identifies with nature). We found that people who visited more diverse types of natural spaces (ranging from wild nature, managed parks, and beaches) had higher life satisfaction. The presence of nature views from windows at the home and/or at the workplace was also linked with higher life satisfaction. We also found that people with a stronger connection with nature had higher life satisfaction when they spent more than one hour in natural spaces per week, while this relationship was weak for people without a strong connection with nature. Our results suggest that urban planning should aim to provide a diversity of natural spaces to increase life satisfaction.

Understanding extinction of experience

Gaston, K.J. & Soga, M. 2020. Extinction of experience: the need to be more specific. People and Nature [online early].

1. Extinction of experience, the progressive loss of human–nature interactions, may prove to be one of the key environmental concepts of our times. Not only does this loss reduce the important benefits that people gain from these interactions, but it may also undermine their support for pro-biodiversity policies and management actions, and thus play an important role in shaping the future of biodiversity.

2. Here, to help improve understanding, encourage a more consistent approach and highlight research gaps, we consider some of the key features of the concept of extinction of experience, contentions that these have caused and propose some solutions.

3. We focus particularly on the importance of (a) the definition of nature employed; (b) whether direct or other human–nature interactions are considered; (c) the differences between the loss and the extinction of experience; (d) the timing of the loss of interactions that is considered; and (e) the difference between human–nature interactions and human–nature experiences.

4. Differentiating between narrow and broad senses of nature, between childhood and lifelong timings, and between interactions and experiences leads to a typology of eight different forms of extinction of experience. Such a classification can be useful for targeting research, furthering understanding of the processes and dynamics of the extinction of experience, and developing policies to reduce this phenomenon and minimize its negative consequences.

Lighting up a nation

Cox, D.T.C., Sánchez de Miguel, A., Dzurjak, S.A., Bennie, J. & Gaston, K.J. 2020. National scale spatial variation in artificial light at night. Remote Sensing 12, 1591.

[Image: NASA]

 The disruption to natural light regimes caused by outdoor artificial nighttime lighting has significant impacts on human health and the natural world. Artificial light at night takes two forms, light emissions and skyglow (caused by the scattering of light by water, dust and gas molecules in the atmosphere). Key to determining where the biological impacts from each form are likely to be experienced is understanding their spatial occurrence, and how this varies with other landscape factors. To examine this, we used data from the Visible Infrared Imaging Radiometer Suite (VIIRS) day/night band and the World Atlas of Artificial Night Sky Brightness, to determine covariation in (a) light emissions, and (b) skyglow, with human population density, landcover, protected areas and roads in Britain. We demonstrate that, although artificial light at night increases with human density, the amount of light per person decreases with increasing urbanization (with per capita median direct emissions three times greater in rural than urban populations, and per capita median skyglow eleven times greater). There was significant variation in artificial light at night within different landcover types, emphasizing that light pollution is not a solely urban issue. Further, half of English National Parks have higher levels of skyglow than light emissions, indicating their failure to buffer biodiversity from pressures that artificial lighting poses. The higher per capita emissions in rural than urban areas provide different challenges and opportunities for mitigating the negative human health and environmental impacts of light pollution. 

Internet ecology

Jarić, I., Correia, R.A., Brookl B.W., Buettel, J.C., Courchamp, F., Di Minin, E., Firth, J.A., Gaston, K.J., Jepson, P., Kalinkat, G., Ladle, R., Soriano-Redondo, A., Souza, A.T. & Roll, U. 2020. iEcology: Harnessing large online resources to generate ecological insights. Trends in Ecology and Evolution [online early].

Digital data are accumulating at unprecedented rates. These contain a lot of information about the natural world, some of which can be used to answer key ecological questions. Here, we introduce iEcology (i.e., internet ecology), an emerging research approach that uses diverse online data sources and methods to generate insights about species distribution over space and time, interactions and dynamics of organisms and their environment, and anthropogenic impacts. We review iEcology data sources and methods, and provide examples of potential research applications. We also outline approaches to reduce potential biases and improve reliability and applicability. As technologies and expertise improve, and costs diminish, iEcology will become an increasingly important means to gain novel insights into the natural world.

Diffuse light is real light

Sánchez de Miguel, A., Kyba, C.C.M., Zamorano, J., Gallego, J. & Gaston, K.J. 2020. The nature of the diffuse light near cities detected in nighttime satellite imagery. Scientific Reports 10, 7829.

Diffuse glow has been observed around brightly lit cities in nighttime satellite imagery since at least the first publication of large scale maps in the late 1990s. In the literature, this has often been assumed to be an error related to the sensor, and referred to as “blooming”, presumably in relation to the effect that can occur when using a CCD to photograph a bright light source. Here we show that the effect seen on the DMSP/OLS, SNPP/VIIRS-DNB and ISS is not only instrumental, but in fact represents a real detection of light scattered by the atmosphere. Data from the Universidad Complutense Madrid sky brightness survey are compared to nighttime imagery from multiple sensors with differing spatial resolutions, and found to be strongly correlated. These results suggest that it should be possible for a future space-based imaging radiometer to monitor changes in the diffuse artificial skyglow of cities.

Ecology of interactions between people and nature

Soga, M. & Gaston, K.J. (2020) The ecology of human-nature interactions. Proc. R. Soc. B, online early.

The direct interactions between people and nature are critically important in many ways, with growing attention particularly on their impacts on human health and wellbeing (both positive and negative), on people’s attitudes and behaviour towards nature, and on the benefits and hazards to wildlife. A growing evidence base is accelerating the understanding of different forms that these direct human–nature interactions take, novel analyses are revealing the importance of the opportunity and orientation of individual people as key drivers of these interactions, and methodological develop- ments are increasingly making apparent their spatial, temporal and socio- economic dynamics. Here, we provide a roadmap of these advances and identify key, often interdisciplinary, research challenges that remain to be met. We identified several key challenges, including the need to characterize individual people’s nature interactions through their life course, to deter- mine in a comparable fashion how these interactions vary across much more diverse geographical, cultural and socio-economic contexts that have been explored to date, and to quantify how the relative contributions of people’s opportunity and orientation vary in shaping their nature inter- actions. A robust research effort, guided by a focus on such unanswered questions, has the potential to yield high-impact insights into the fundamen- tal nature of human–nature interactions and contribute to developing strategies for their appropriate management.

Allotments for food

Edmondson, J.L., Childs, D.Z., Dobson, M.C., Gaston, K.J., Warren, P.H. & Leake, J.R. 2020. Feeding a city – Leicester as a case study of the importance of allotments for horticultural production in the UK. Science of the Total Environment, in press.

The process of urbanization has detached a large proportion of the global population from involvement with food production. However, there has been a resurgence in interest in urban agriculture and there is widespread recognition by policy-makers of its potential contribution to food security. Despite this, there is little data on urban agricultural production by non-commercial small-scale growers. We combine citizen science data for self-provisioning crop yields with field-mapping and GIS-based analysis of allotments in Leicester, UK, to provide an estimate of allotment fruit and vegetable production at a city-scale. In addition, we examine city-scale changes in allotment land provision on potential crop production over the past century. The average area of individual allotment plots used to grow crops was 52%. Per unit area yields for the majority of crops grown in allotments were similar to those of UK commercial horticulture. We estimate city-wide allotment production of >1200 t of fruit and vegetables and 200 t of potatoes per annum, equivalent to feeding >8500 people. If the 13% of plots that are completely uncultivated were used this could increase production to >1400 t per annum, feeding ~10,000 people, however this production may not be located in areas where there is greatest need for increased access to fresh fruits and vegetables. The citywide contribution of allotment cultivation peaked in the 1950s when 475 ha of land was allotments, compared to 97 ha currently. This suggests a decline from >45,000 to <10,000 of people fed per annum. We demonstrate that urban allotments make a small but important contribution to the fruit and vegetable diet of a UK city. However, further urban population expansion will exert increasing development pressure on allotment land. Policy-makers should both protect allotments within cities, and embed urban agricultural land within future developments to improve local food security.