69 research outputs found
Expanding a classic woodland food chain into a geographically variable food web
No full textThere is ample evidence that climate change is impacting on phenology and it has been
suggested that this may generate trophic mismatches. A key system for investigating
phenology and trophic mismatch occurs in spring in temperate deciduous woodlands, where
folivorous caterpillars and their predators, insectivorous passerines, are reliant upon
ephemeral resources for reproductive success and survival. However, studies are primarily
conducted within single-site, oak- (Quercus sp) dominated woodland and focus on a single
caterpillar species, winter moth (Operophtera brumata), despite these passerines being
habitat generalists with large geographic ranges. It remains to be seen whether insights
gained from these studies can be generalised on the landscape scale across different habitats.
In this thesis, I explore the extent to which geographic and habitat variation operates in this
system and attempt to expand the system beyond a linear single-species food chain into a
more biologically realistic multi-species food web. I also identify the most important
environmental factors predicting the phenology of the passerines to allow better predictions
of how their phenology could alter under future climate change scenarios. To address these
questions, I established a novel 220km transect of Scotland incorporating 40 field sites that
vary in elevation and the type of deciduous woodland habitat, monitoring six blue tit
(Cyanistes caeruleus) nestboxes, tree and invertebrate phenology and abundance, at each site
throughout the springs of 2014-16.
Firstly, I assess how blue tit occupancy and productivity are affected by the variation in fine-scale
woodland habitat, latitude, elevation and prey availability that exists along the transect
(Chapter 2). I find that habitat variables strongly affect fledging success but not occupancy
or clutch size, whilst occupancy exhibits biogeographic trends, revealing that the relationship
between breeding decisions and outcomes differs among habitats and implies that it may be
difficult to generalise results from one habitat to others.
Next, I aim to identify the environmental aspects which play a role in regulating blue tit
reproductive phenology by examining the ability of temperature, tree phenology,
invertebrate prey abundance and photoperiod to predict nest initiation and laying dates
(Chapter 3). I find that night-time temperature in early spring is the most important predictor
of both nest initiation and lay date (slopes ~ -3days/°C) and I suggest that this supports the
hypothesis that temperature acts as a constraint on timing rather than a cue. Invertebrate
abundance is also a positive correlate of lay date, possibly allowing fine-tuning of timing.
This knowledge provides clearer foundations from which to predict future phenological
change and possible trophic mismatch in this system.
There is the potential that the apparent effect of temperature on blue tit reproductive
phenology is indirect and mediated by diet, which is largely undescribed in the period prior
to breeding. Therefore, in Chapter 4 I examine how blue tit diet varies across habitat,
geography and time, and whether there is a dietary cue utilised to initiate breeding
phenology, using data from metabarcoding faeces collected from nestbox-roosting adults in
early spring. Geographic variation in diet is substantial, with high site-to-site dietary
turnover (β-diversity), as well as high turnover along the elevational and latitudinal gradients
studied. Dietary α-diversity (richness) is unaffected by geographical variables, but increases
over time, with significant pre-breeding dietary increases in Lepidoptera and Hemiptera
signifying a possible cue. In addition, these data provide the most comprehensive next-generation
insights into the diet of a wild bird to date and identify 432 prey taxa.
Finally, I analyse how biogeographic and habitat variables affect the phenology, abundance
and diversity of caterpillars (Chapter 5). Host tree species’ varied significantly in their
likelihood of hosting a caterpillar, with oak and willow (Salix sp.) the most likely.
Biogeography had less effect on the likelihood of caterpillar occurrence, but elevation
delayed peak date by 3.7 days/100m increase. There was also support for the spring
caterpillar peak being dominated by a few key species, with over half of all caterpillars
identified being of just three of the 62 total species, including winter moth. These findings
contribute to understanding how the temporal distribution of caterpillars varies across
habitats on the landscape scale.
Taken together, the findings of this thesis reveal considerable geographic and habitat
variation throughout this system, in both the composition of the food web and the impacts on
blue tit productivity, demonstrating why caution must be exercised when extrapolating
findings from one location or habitat to others
Plunger Head or Valve.
No full textPatent for a plunger head or valve, which cannot come unscrewed accidentally while inside a pump
Data from: A spatial perspective on the phenological distribution of the spring woodland caterpillar peak
No full textFive files listed below: JSMBAP_Caterpillars: Details of all individual caterpillars collected (by branch beating) and identified along our Scottish transect of 40 woodland field sites 2014-16. JSMBAP_Branch_Beating: Details on each branch beating and whether or not a caterpillar was captured. From our Scottish transect 2014-16. JSMBAP_Habitat: Habitat data of each of the 40 field sites along our Scottish transect. JSMBAP_Nestbox_Details: Geographic details of each bird nestbox (and site) on our 40-site Scottish transect 2014-16. JSMBAP_Tree_Phenology: Tree phenology data for each focal tree studied along our Scottish transect of 40 field sites 2014-16.A classic system for studying trophic mismatch focuses on the timing of the spring caterpillar peak in relation to the breeding time and productivity of woodland passerine birds. Most work has been conducted in single-site oak woodlands and little is known about how insights generalise to other woodland types or across space. Here we present the results of a three-year study on the species composition and temporal distribution of the spring caterpillar peak on different tree taxa across 40 woodland sites spanning two degrees of latitude in Scotland. We used molecular barcoding to identify 62 caterpillar species, with winter moth (Operophtera brumata) the most abundant, comprising a third of the sample. Oak (Quercus sp.) and willow (Salix sp.) hosted significantly higher caterpillar abundances than other tree taxa, with winter moth exhibiting similar trends and invariantly proportionate across tree taxa. Caterpillar peak phenology was broadly similar between tree taxa. While latitude had little effect, increasing elevation increased the height of the caterpillar peak and retarded timing by 3.7 days/100m. These findings extend our understanding of how mismatch may play out spatially, with caterpillar peak date varying with elevation, and tree taxa varying in the caterpillar resource that they host.When using this data, please cite the original publication: Citation is not yet available for this publication from The American Naturalist. It will become available shortly after the publication appears. Additionally, please cite the Dryad data package: Shutt JD, Burgess MD, Phillimore AB (2019) Data from: A spatial perspective on the phenological distribution of the spring woodland caterpillar peak. Dryad Digital Repository. https://doi.org/10.5061/dryad.71568m
A metabarcoding study of spatiotemporal variation in blue tit diet prior to breeding: preregistration plan
No full textA metabarcoding study of spatiotemporal variation in blue tit diet prior to breeding: preregistration plan
No full textRethinking bird feeding: are we putting extra pressure on some struggling woodland birds?
No full textA metabarcoding study of spatiotemporal variation in blue tit diet prior to breeding: preregistration plan
No full textKilling with kindness: Does widespread generalised provisioning of wildlife help or hinder biodiversity conservation efforts?
No full textProvisioning of wildlife with food, water and breeding sites is a globally ubiquitous phenomenon. While some provisioning is targeted at single species of conservation concern, generalised provisioning is more common and can exceed the local availability of natural resources for recipient taxa. Generalised provisioning is enthusiastically promoted by many conservation organisations as a means to foster connection with nature and help wildlife. However, such a vast input of additional resources into the environment must have diverse, ecosystem-wide consequences. Direct effects upon recipient taxa have garnered most research interest, and are generally positive in leading to increased survival, productivity and hence population growth. However, we argue that the wider implications for the recipients' non-provisioned competitors, prey and predators are underappreciated and have the potential to generate pervasive negative impacts for biodiversity. The impact of provisioning has also hitherto been considered predominantly in urban contexts, overlooking the movements of wildlife to and from provisioning sources and the widespread nature of both human settlements and provisioning, underappreciating the potential scale of impact. Using a case study of UK garden bird food and nestbox provisioning, we hypothesise how well-intentioned provisioning could be contributing to widespread ecological community change and homogenisation. This may consequently help drive declines in species of conservation concern by asymmetrically benefitting common and adaptable species, leaving their competitors exposed to enhanced direct competition, hyperpredation, mesopredator release and heightened disease transmission risks. We recommend further research into these ecosystem cascades and a more cautious, evidence-based approach to the encouragement of provisioning wildlife
The literary phenomenon of 'conflation’ in the reworking of Paul’s letter to the Colossians by the author of the letter to the Ephesians
No full textThis thesis is concerned with the nature of the relationship of the Letter to the Ephesians (Eph) to Paul's Letter to the Colossians (Col).The first three chapters seek to argue that this relationship should be designated as "literary dependent". In Chapter I the suggestion made by A.T. Lincoln (Dallas [Texas], 1990) that the contemporary redaction of the Letter of Aristeas by Josephus in his Jewish Antiquities, Book XII, §§ 11-118 is similar to the use the author of Eph made of Col, is exposed to critical review. Chapter II focuses on the phenomenon of repeated 'conflation' in Eph. This literary phenomenon entails that several 'Colossian' texts from different parts of Col are conflated by the author of Eph into one passage and is subjected to exhaustive analysis. It is argued that conflation is the main feature of the literary dependence of Eph on Col but does not occur in Josephus' reworking of the Letter of Aristeas. Chapter III continues the comparison between the method of reworking employed in the Jewish Antiquities and in Eph by pointing out that the fluctuation in verbatim agreement of one document with its source can be meaningful. Chapter IV provides the new synopsis of both letters on which the whole examination is based. This synoptic overview is a desideratum since the previous synoptic editions of the Greek text of both letters by E.J. Goodspeed (Chicago, 1933) and C.L. Mitton (Oxford, 1951) are not accurate enough and unsuitable for research that focuses on the conflations of 'Colossian' verses in Eph. The fifth and last chapter deals with the question why Eph is literary dependent on Col and shows that despite the literary dependence, the theology of Eph is distinctive in comparison with its source Col. The distinctiveness of Eph's theology consists in a critical modification of the stress which Col places on Christ's already accomplished victory over the cosmic powers (Co/ 2.15). In order to safeguard an authoritative reception of his modification of Col, the author of Eph presented his letter as the parallel letter of Col alluded to m Col 4.16. The literary dependence on Col is necessary both to modify its content and to present his own writing as its parallel letter
Data from: A spatial perspective on the phenological distribution of the spring woodland caterpillar peak
No full textA classic system for studying trophic mismatch focuses on the timing of the spring caterpillar peak in relation to the breeding time and productivity of woodland passerine birds. Most work has been conducted in single-site oak woodlands and little is known about how insights generalise to other woodland types or across space. Here we present the results of a three-year study on the species composition and temporal distribution of the spring caterpillar peak on different tree taxa across 40 woodland sites spanning two degrees of latitude in Scotland. We used molecular barcoding to identify 62 caterpillar species, with winter moth (Operophtera brumata) the most abundant, comprising a third of the sample. Oak (Quercus sp.) and willow (Salix sp.) hosted significantly higher caterpillar abundances than other tree taxa, with winter moth exhibiting similar trends and invariantly proportionate across tree taxa. Caterpillar peak phenology was broadly similar between tree taxa. While latitude had little effect, increasing elevation increased the height of the caterpillar peak and retarded timing by 3.7 days/100m. These findings extend our understanding of how mismatch may play out spatially, with caterpillar peak date varying with elevation, and tree taxa varying in the caterpillar resource that they host
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