The ecological effects of slope and aspect in chalk grassland

The microclimate of plants growing close to the ground is strongly influenced by the orientation of a soil/vegetation surface with respect to the sun's rays (slope and aspect). In chalk grassland in the UK, slopes of contrasting aspect frequently have distinctive patterns of vegetation. A series of climatic and microclimatic measurements were made at field sites indifferent regions on the English chalk (North Dorset and the Yorkshire Wolds) during the period June 2000 to September 2002. Using digital terrain models (DTMs), process-based models of microclimatic variables at different points in the landscape were developed. The mechanisms through which topography may influence vegetation and species distribution were investigated with field experiments and measurements. Both existing vegetation data from Perring (1956) and new data collected from the field sites were analysed using detrended correspondence analysis (DCA) and generalised additive models (GAMs), to elucidate the relationships between vegetation and soil, topography and climate. A consistent gradient in chalk grassland vegetation was found across spatial scales, associated with the frequency of species with a "stress tolerant” strategy. This gradient in vegetation is apparently driven by species' responses to several separate, but often correlated, variables including soil moisture, maximum summer temperatures and soil fertility. Over the past 50 years, stress tolerant species have declined in frequency at the North Dorset field site, Ellenberg fertility indices have increased and light indices have decreased. The observed changes are consistent with fertilization from atmospheric N deposition and/or relaxation of rabbit grazing after the myxomatosis outbreak in the 1950s. Plots on sloping ground, and in particular, south-west facing slopes, were least affected by these changes, suggesting that high temperatures, phosphorus and water limitation have acted as a buffer against vegetation change, and that complex topography creates refuges for stress tolerant species in the landscape

Ecological effects of artificial light at night on wild plants

PublishedSummary 1.Plants use light as a source of both energy and information. Plant physiological responses to light, and interactions between plants and animals (such as herbivory and pollination), have evolved under a more or less stable regime of 24-h cycles of light and darkness, and, outside of the tropics, seasonal variation in day length. 2.The rapid spread of outdoor electric lighting across the globe over the past century has caused an unprecedented disruption to these natural light cycles. Artificial light is widespread in the environment, varying in intensity by several orders of magnitude from faint skyglow reflected from distant cities to direct illumination of urban and suburban vegetation. 3.In many cases, artificial light in the night-time environment is sufficiently bright to induce a physiological response in plants, affecting their phenology, growth form and resource allocation. The physiology, behaviour and ecology of herbivores and pollinators are also likely to be impacted by artificial light. Thus, understanding the ecological consequences of artificial light at night is critical to determine the full impact of human activity on ecosystems. 4.Synthesis. Understanding the impacts of artificial night-time light on wild plants and natural vegetation requires linking the knowledge gained from over a century of experimental research on the impacts of light on plants in the laboratory and glasshouse with knowledge of the intensity, spatial distribution, spectral composition and timing of light in the night-time environment. To understand fully the extent of these impacts requires conceptual models that can (i) characterize the highly heterogeneous nature of the night-time light environment at a scale relevant to plant physiology; and (ii) scale physiological responses to predict impacts at the level of the whole plant, population, community and ecosystem.ERC under the European Union's Seventh Framework programm

Artificial light alters natural regimes of night-time sky brightness

PMCID: PMC3634108Open access journalArtificial light is globally one of the most widely distributed forms of anthropogenic pollution. However, while both the nature and ecological effects of direct artificial lighting are increasingly well documented, those of artificial sky glow have received little attention. We investigated how city lights alter natural regimes of lunar sky brightness using a novel ten month time series of measurements recorded across a gradient of increasing light pollution. In the city, artificial lights increased sky brightness to levels six times above those recorded in rural locations, nine and twenty kilometers away. Artificial lighting masked natural monthly and seasonal regimes of lunar sky brightness in the city, and increased the number and annual regime of full moon equivalent hours available to organisms during the night. The changes have potentially profound ecological consequences.European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013

Topographic microclimates drive microhabitat associations at the range margin of a butterfly

Journal Article© 2014 The Authors. Ecography published by Nordic Society Oikos.The habitat associations of individuals underpin the dynamics of species distributions. Broad-scale gradients in climate can alter habitat associations across species' geographic ranges, but topographic heterogeneity creates local microclimates which could generate variation in habitat use at finer spatial scales. We examined the selection of microhabitats for egg-laying by populations of a thermally-constrained butterfly, the skipper Hesperia comma, across 16 sites with different regional temperatures and topographic microclimates. Using models of thermal microclimate, we examined how the association between eggs and warm bare ground microhabitats varied with ambient temperature, and predicted bare ground associations in 287 existing H. comma populations, to investigate the relative impacts of regional temperatures and topographic microclimates on microhabitat use. Eggs were most strongly associated with bare ground in relatively cool sites, indicating climate-driven changes in microhabitat use. The majority of temperature variation between study sites was attributable to topographic microclimates rather than regional temperature differences, such that changes in microhabitat associations occurred principally between north- and south-facing slopes within the same region. Predicted microhabitat associations across the UK distribution of H. comma showed that, due to the large temperature differences generated by topography, most of the between-population variation in microhabitat use occurs locally within 5 km grid squares, with a smaller proportion occurring at a regional level between 5 km squares. Our findings show how microclimatic variation generated by topography alters the habitat associations of populations at fine spatial scales, suggesting that microclimate-driven changes in habitat suitability could shape species' distribution dynamics and their responses to environmental change.NERCUniversity of Exete

Stemming the tide of light pollution encroaching into Marine Protected Areas

Open Access journalMany marine ecosystems are shaped by regimes of natural light guiding the behaviour of their constituent species. As evidenced from terrestrial systems, the global introduction of nighttime lighting is likely influencing these behaviours, restructuring marine ecosystems, and compromising the services they provide. Yet the extent to which marine habitats are exposed to artificial light at night is unknown. We quantified nightime artificial light across the world's network of Marine Protected Areas (MPAs). Artificial light is widespread and increasing in a large percentage of MPAs. While increases are more common among MPAs associated with human activity, artificial light is encroaching into a large proportion of even those marine habitats protected with the strongest legislative designations. Given the current lack of statutory tools, we propose that allocating ‘marine dark sky park’ status to MPAs will help incentivize responsible authorities to hold back the advance of artificial light.European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013

Using the Behavior Change Wheel to Understand University Students’ Prolonged Sitting Time and Identify Potential Intervention Strategies

Background Several national public health guidelines recommend individuals minimize time spent in prolonged, continuous periods of sitting. Developing effective interventions to break up sitting, however, requires in-depth understanding of the behavior as well as identification of the key elements that need to be targeted to achieve change. This qualitative study focused on university students – a highly sedentary group – with the aim of: (i) exploring the factors influencing prolonged sitting time in this population; and (ii) identifying potential avenues for future intervention, based on the Behavior Change Wheel framework. Method Eighteen ambulatory undergraduate students participated in semi-structured one-on-one interviews, using the Capability, Opportunity, Motivation, Behavior (COM-B) model and the complementary Theoretical Domains Framework (TDF) as the theoretical framework. Data were analyzed using a directed content analysis approach, followed by inductive thematic analysis. Results All COM-B components and eight TDF domains were identified as relevant for influencing the target behavior. Conclusion Findings suggest that interventions and policies aimed at reducing prolonged sitting time in university students should: (i) raise awareness about negative health implications; (ii) address productivity concerns; (iii) provide training in behavioral self-regulation; (iv) use external reminders; (v) implement habit formation techniques; and (vi) promote social acceptability for breaking up sitting

Active Management of Protected Areas Enhances Metapopulation Expansion Under Climate Change

Journal ArticleCopyright © 2013 The Authors. Conservation Letters published by Wiley Periodicals, Inc.There is a need to adapt biodiversity conservation to climate change, but few empirical studies are available to guide decision-making. Existing networks of protected areas (PAs) have been preferentially colonized during species' range expansions, but this could be due to their original habitat quality and/or to ongoing management activity. Here, we examine how PA status and active conservation management have influenced the range expansion of a butterfly Hesperia comma through fragmented landscapes. PAs under active conservation management were over three times more likely to be colonized than unprotected, unmanaged sites of the same basic vegetation type. Conservation action also increased the survival rate of existing populations inside and outside of PAs. We conclude that PAs facilitate range expansions by preventing habitat degradation and encouraging active conservation that improves habitat quality, and that conservation interventions on nondesignated sites also have a role to play in adapting conservation to climate change.NERCUniversity of Exete

Artificial Light at Night Causes Top‐down and Bottom‐up Trophic Effects on Invertebrate Populations

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.1. Globally, many ecosystems are exposed to artificial light at night. Nighttime lighting has direct biological impacts on species at all trophic levels. However, the effects of artificial light on biotic interactions remain, for the most part, to be determined. 2. We exposed experimental mesocosms containing combinations of grassland plants and invertebrate herbivores and predators to illumination at night over a three-year period to simulate conditions under different common forms of street lighting. 3. We demonstrate both top-down (predation controlled) and bottom-up (resource controlled) impacts of artificial light at night in grassland communities. The impacts on invertebrate herbivore abundance were wavelength dependent and mediated via other trophic levels. 4. White LED lighting decreased the abundance of a generalist herbivore mollusc by 55% in the presence of a visual predator, but not in its absence, while monochromatic amber light (with a peak wavelength similar to low pressure sodium lighting) decreased abundance of a specialist herbivore aphid (by 17%) by reducing the cover and flower abundance of its main food plant in the system. Artificial white light also significantly increased the food plant’s foliar carbon to nitrogen ratio. 5. We conclude that exposure to artificial light at night can trigger ecological effects spanning trophic levels, and that the nature of such impacts depends on the wavelengths emitted by the lighting technology employed. 6. Policy implications. Our results confirm that artificial light at night, at illuminance levels similar to roadside vegetation, can have population effects mediated by both top-down and bottom-up effects on ecosystems. Given the increasing ubiquity of light pollution at night, these impacts may be widespread in the environment. These results underline the importance of minimising ecosystem disruption by reducing light pollution in natural and semi-natural ecosystems.The research leading to this paper was funded by the European Research Council under the European Union’s Seventh Framework programme (FP7/2007-2013)/ERC grant agreement no. 268504 to KJG

Population turnover, habitat use and microclimate at the contracting range margin of a butterfly

Copyright © Springer International Publishing Switzerland 2014This is a post print version. The final publication is available at Springer via http://dx.doi.org/ 10.1007/s10841-014-9710-0There is another ORE record for this publication: http://hdl.handle.net/10871/31357Climate change is expected to drive patterns of extinction and colonisation that are correlated with geographic gradients in the climate, such as latitude and elevation. However, local population dynamics also depend on the fine-scale effects of vegetation and topography on resource availability and microclimate. Understanding how this fine-scale variation influences population survival in the face of changing climatic favourability could provide clues for adapting conservation to climate change. Here, we document a long-term decline of the butterfly Parnassius apollo in the Sierra de Guadarrama mountain range in central Spain, and examine recent population turnover and habitat use by the species to make inferences about its ecology and conservation. A decline since the 1960s throughout the elevation range suggests a regional deterioration in favourability for the species. Since 2006, local habitat quality has been the main correlate of population persistence, with populations that persisted from 2006 to 2012 associated with high availability of larval host plants. At a finer resolution, the larval distribution in a network of suitable habitat in 2011 and 2012 was most closely related to bare ground cover. Thus, although slope, aspect and elevation lead to considerable variation in microhabitat temperatures during the period of P. apollo larval development, vegetation structure appears to have been the most critical factor for local habitat use and population persistence. The results show that site selection and management retain key roles in conservation despite the broad-scale effects of environmental change.Universidad Rey Juan Carlos/Comunidad de MadridSpanish Ministry of Education and ScienceRoyal Society of Londo