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Millon A.,CNRS Mediterranean Institute for Biodiversity and Ecology Marine and Continental | Millon A.,University of Aberdeen | Petty S.J.,University of Aberdeen | Petty S.J.,Center for Human and Ecological science | And 4 more authors.
Global Change Biology | Year: 2014

Predicting the dynamics of animal populations with different life histories requires careful understanding of demographic responses to multifaceted aspects of global changes, such as climate and trophic interactions. Continent-scale dampening of vole population cycles, keystone herbivores in many ecosystems, has been recently documented across Europe. However, its impact on guilds of vole-eating predators remains unknown. To quantify this impact, we used a 27-year study of an avian predator (tawny owl) and its main prey (field vole) collected in Kielder Forest (UK) where vole dynamics shifted from a high- to a low-amplitude fluctuation regime in the mid-1990s. We measured the functional responses of four demographic rates to changes in prey dynamics and winter climate, characterized by wintertime North Atlantic Oscillation (wNAO). First-year and adult survival were positively affected by vole density in autumn but relatively insensitive to wNAO. The probability of breeding and number of fledglings were higher in years with high spring vole densities and negative wNAO (i.e. colder and drier winters). These functional responses were incorporated into a stochastic population model. The size of the predator population was projected under scenarios combining prey dynamics and winter climate to test whether climate buffers or alternatively magnifies the impact of changes in prey dynamics. We found the observed dampening vole cycles, characterized by low spring densities, drastically reduced the breeding probability of predators. Our results illustrate that (i) change in trophic interactions can override direct climate change effect; and (ii) the demographic resilience entailed by longevity and the occurrence of a floater stage may be insufficient to buffer hypothesized environmental changes. Ultimately, dampened prey cycles would drive our owl local population towards extinction, with winter climate regimes only altering persistence time. These results suggest that other vole-eating predators are likely to be threatened by dampening vole cycles throughout Europe. © 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.


Dandy N.,Center for Human and Ecological Science | Van Der Wal R.,University of Aberdeen
Landscape and Urban Planning | Year: 2011

Woodlands and forests perform multiple functions for contemporary society. Their management affects, and is affected by, numerous stakeholders each of which relate to and appreciate woodlands in distinct ways. Capturing these stakeholder preferences for inclusion within increasingly collaborative planning and management processes is recognised as an important task. This paper describes and analyses an innovative, strongly qualitative method (field-based interactive photo-elicitation) via which to achieve this. Small groups of research participants were taken to visit, and thus experience, three predominantly oak woodlands in the UK, representing different levels of deer browsing. The impact of large herbivores is strongly related to the functions that woodlands can perform, but their management can be particularly contentious and thus perhaps a key challenge to stakeholder collaboration. The participants' were encouraged to record this experience through taking photographs, and making notes. These photographs and notes formed the stimulus for group discussion, immediately following the field visits. Data analysis followed an inductive ('grounded') approach and identified seven key themes in the participants reported preferences for woodland landscapes. We conclude that the method advances the field of landscape preference assessment and can capture stakeholder preferences in a rich and cost-effective manner. The research identified substantial shared appreciation of woodland landscapes across 'professional' and 'lay' social groups, challenging several previous studies. © 2011.


Millon A.,University of Aberdeen | Millon A.,Aix - Marseille University | Petty S.J.,University of Aberdeen | Petty S.J.,Center for Human and Ecological science | And 2 more authors.
Journal of Animal Ecology | Year: 2011

Natal conditions and senescence are two major factors shaping life-history traits of wild animals. However, such factors have rarely been investigated together, and it remains largely unknown whether they interact to affect age-specific performance. We used 27years of longitudinal data collected on tawny owls with estimates of prey density (field voles) from Kielder Forest (UK) to investigate how prey density at birth affects ageing patterns in reproduction and survival. Natal conditions experienced by tawny owls, measured in terms of vole density, dramatically varied among cohorts and explained 87% of the deviance in first-year apparent survival (annual estimates ranging from 0·07 to 0·33). We found evidence for senescence in survival for females as well as for males. Model-averaged estimates showed that adult survival probability declined linearly with age for females from age1. In contrast, male survival probability, lower on average than for female, declined after a plateau at age1-3. We also found evidence for reproductive senescence (number of offspring). For females, reproductive performance increased until age9 then declined. Males showed an earlier decline in reproductive performance with an onset of senescence at age3. Long-lasting effects of natal environmental conditions were sex specific. Female reproductive performance was substantially related to natal conditions (difference of 0·24 fledgling per breeding event between females born in the first or third quartile of vole density), whereas male performance was not. We found no evidence for tawny owls born in years with low prey density having accelerated rates of senescence. Our results, combined with previous findings, suggest the way natal environmental conditions affect senescence varies not only across species but also within species according to gender and the demographic trait considered. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.


Millon A.,University of Aberdeen | Petty S.J.,University of Aberdeen | Petty S.J.,Center for Human and Ecological science | Lambin X.,University of Aberdeen
Journal of Animal Ecology | Year: 2010

1. According to life-history theory, environmental variability and costs of reproduction account for the prevalence of delayed reproduction in many taxa. Empirical estimates of the fitness consequences of different ages at first breeding in a variable environment are few however such that the contributions of environmental and individual variability remains poorly known. 2. Our objectives were to elucidate processes that underpin variation in delayed reproduction and to assess lifetime consequences of the age of first breeding in a site-faithful predator, the tawny owl Strix aluco L. subjected to fluctuating selection linked to cyclical variation in vole density (typically 3-year cycles with low, increasing and decreasing vole densities in successive years). 3. Amultistate capture-recapture model revealed that owl cohorts had strikingly different juvenile survival prospects, with estimates ranging from 0·08 to 0·33 respectively for birds born in Decrease and Increase phases of the vole cycle. This resulted in a highly skewed population structure with >75% of local recruits being reared during Increase years. In contrast, adult survival remained constant throughout a vole cycle. The probability of commencing reproduction was lower at age 1 than at older ages, and especially so for females. From age 2 onwards, pre-breeders had high probabilities of entering the breeding population. 4. Variation in lifetime reproductive success was driven by the phase of the vole cycle in which female owls started their breeding career (26-47% of variance explained, whether based on the number of local recruits or fledglings), more than by age at first breeding or by conditions experienced at birth. Females who postponed reproduction to breed for the first time at age 3 during an Increase phase, produced more recruits, even when accounting for birds that may have died before reproduction. No such effects were detected for males. 5. Sex-specific costs of early reproduction may have accounted for females being more prone to delay reproduction. Contrary to expectations from a best-of-a-bad job strategy, early-hatched, hence potentially higher-quality females were more likely to breed at age 1, but then experienced rapidly declining food resources and so seemed caught in a life-history trap set by the multiannual vole cycle. ©2009 The Authors. Journal compilation ©2009 British Ecological Society.


O'Brien L.,Center for Human and Ecological science | Marzano M.,Center for Human and Ecological science | White R.M.,University of St. Andrews
Science and Public Policy | Year: 2013

Calls for new models of knowledge production demand more interdisciplinary research in order to: develop holistic solutions, increased stakeholder participation, to consider a plurality of perspectives, and to support a more deliberative democracy approach. However, knowledge production debates have rarely explored the synergies offered through combinations of different research attributes. We develop the concept of 'participatory interdisciplinarity' to explore the engagement of a wide range of stakeholders by groups of researchers from different disciplines. This paper examines the benefits and challenges of: interdisciplinarity, stakeholder participation, the integration of interdisciplinarity and participation. We conclude that participatory interdisciplinary approaches can quickly improve understanding and communication amongst both researchers and stakeholders involved in management, with less evidence of immediate instrumental benefits. We outline how 'participatory interdisciplinarity' can assist in breaking down barriers between traditional knowledge roles (researcher/stakeholder) and knowledge forms (academic/ local) and in activating more integrated environmental management. © Crown copyright 2013.


Lawrence A.,Center for Human and Ecological science | Stewart A.,Japan Forestry and Forest Products Research Institute
Mathematical and Computational Forestry and Natural-Resource Sciences | Year: 2011

This paper explores the evidence for successful participatory forest decision-making which uses computer-based tools. Both the technical and social complexity of forest decision-making are increasing, as managers seek to forecast and provide goods and services on a sustainable basis, while also interacting with a wide range of stakeholders. The paper draws on forest science and management literature, environmental studies and social science to review experiences of success in combining the challenges of participation and technological advancement. It shows that, while there is no shortage of literature outlining methods and processes, the perceptions, attitudes and values of the stakeholders may constrain implementation. The approaches rely on decision support tools, whose workings may be incomprehensible to some of the stakeholders. The paper highlights the concept of 'usability' to assess the value of such tools, and uses case studies to illustrate the need for users to contribute to the design and testing of the tools. More documentation is needed to help understand which tools are used, adopted, and lead to useful outcomes. © 2011 Publisher of the Mathematical and Computational Forestry & Natural-Resource Sciences.


Gill R.M.A.,Center for Human and Ecological science | Morgan G.,Center for Human and Ecological science
Forestry | Year: 2010

Relatively little information is available to indicate how the impacts of deer vary in relation to densities of deer encountered in lowland environments in Britain. Population densities and impacts of deer on advance regeneration were therefore assessed at 15 sites, embracing a range of densities from 0 to 54.9 deer km-2 in woodland and 0-74.5 km-2 in adjacent fields. Deer densities tended to be higher on sites with drier and more fertile soils, a relationship which may have arisen for either nutritional or management reasons. The log seedling density was negatively correlated with deer density, relative use of woodland vs adjacent fields and deer species (expressed as a proportion of 'larger' species, mainly Fallow deer Dama dama). The abundance of smallest seedlings (<30 cm tall) was also correlated with soil moisture content and tree canopy cover; however, these effects were not significant for larger seedlings (30-150 cm tall), which were instead associated primarily with deer variables. Seedling density declined most sharply at relatively low deer densities, indicating that advanced regeneration is particularly sensitive to deer presence. The results indicate that regeneration is most likely to be inadequate at densities above 14 deer km-2. © 2009 Institute of Chartered Foresters. All rights reserved.


O'Brien L.,Center for Human and Ecological science | Varley P.,University College West
Perspectives in Public Health | Year: 2012

Aims: This paper discusses the use of ethnographic approaches to explore how engagement with natural landscapes might benefit people's health. Methods: Drawing on a selected review of empirical research we identified 30 relevant research papers that utilised qualitative methods to explore health issues and engagement with nature. Three examples of 'alternative' - i.e. non-mainstream qualitative approaches - are used to illustrate how different methods can be used to explore people's experiences of engaging with nature for health. Results: While quantitative methods are dominant in health research, qualitative approaches are becoming more widely used. Approaches such as autoethnography can add value to nature and health studies by providing opportunities for researchers to be self-critical of their role as a researcher. Accompanied visits and visual ethnography can afford the researcher rich data about bodily movement, facial expressions and journeys, as well as dialogues associated with the meanings of nature for health. Conclusions: The paper concludes by suggesting that ethnographic methods can provide useful and important insights into why people engage with the natural environment and the range of health benefits they may gain from contact with nature. Copyright © 2012 Royal Society for Public Health.


Harmer R.,Center for Human and Ecological science | Kiewitt A.,Center for Human and Ecological science | Morgan G.,Center for Human and Ecological science
Forestry | Year: 2012

Silvicultural systems which retain canopy cover during the regeneration phase have become an increasingly important form of management, but their effectiveness in controlling weed species has not been extensively studied. The development of bramble, which is a widespread competitive weed species, was observed within a c. 35-year-old Corsican pine stand thinned to remove 10, 20, 40 and 80 per cent of basal area. Cover, height and numbers of inflorescences and berries were recorded in each of the 3 years following thinning and were generally ranked according to intensity of thinning, but there were no significant differences between treatments. Shoot length, estimated using a grid-intersection method, was significantly lower in the 10 per cent compared with the 40 and 80 per cent thinning treatments. The initial length of bramble shoot present, and basal area and number of trees remaining could be used in various combinations to predict cover, height and shoot length. Although the bramble thicket was generally less well developed in the less-intense thinning treatments, these did not appear to enhance the establishment of trees. Seedlings grew best in the 80 per cent treatment and overall their mean heights were generally lower than that of bramble. Retention of overstorey cover in order to suppress bramble growth and promote tree seedling establishment during forest regeneration may not succeed. © 2012 Institute of Chartered Foresters. All rights reserved.


Xenakis G.,University of Edinburgh | Ray D.,Center for Human and Ecological science | Mencuccini M.,University of Edinburgh
European Journal of Forest Research | Year: 2012

Scots pine is a highly diverse species, extended across Europe from Scandinavia to Spain, Italy, Greece and Turkey. It is also a valuable species, used in many commercial monoculture plantations in Great Britain and particularly in Scotland. Because of the diversity of growing environments and its commercial importance, it is necessary to identify the combination of significant factors affecting the observed variability of growth. Temperature, mainly during the growing season, is quite commonly considered as the most important factor in knowledge-based or empirical models. However, in highly oceanic climates like that of Scotland, the impact of temperature may have a less significant impact on growth. Here we argue that other factors, such as incoming winter solar radiation, frost, drought and management also have a significant effect on the growth of Scots pine. In addition, we argue that the already developed Ecological Site Classification knowledge-based model, used as a forest management tool in Great Britain, should be updated to incorporate our findings. Furthermore, we discuss the need to include management impact and possibly more physiological based components in its growth modelling routines, as these would allow the introduction of the effect of winter solar radiation. © 2011 Springer-Verlag.

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