Fine resolution pollen analysis of late Flandrian II peat at north Gill, north York moors

Pollen and charcoal percentage and concentration analyses have been conducted upon several upland peat profiles of late Flandrian II and early Flandrian III age at North Gill, North York Moors, where earlier research had proven recurrent major pre Elm Decline woodland disturbance, supported in one profile by radiocarbon dating. Fine temporal resolution pollen analysis (FRPA) involving the use of contiguous millimetre sampling was applied to Flandrian II disturbance phases at five of the North Gill profiles. At North Gill 1A a further phase of disturbance near the end of Flandrian II was examined using FRPA to study evidence of pre Elm Decline agricultural activity, and at this profile both the horizontal and vertical resolution limits of the technique were tested by progressively finer sub-sampling. The millimetre level FRPA analyses showed that each of the examined pre Elm Decline disturbance phases was an aggregate feature, composed of a number of smaller sub-phases, the ecological effects of which in terms of spatially-precise woodland successions and community structures were assessed and contrasted. Inter-profile spatial comparison of the ecology of woodland disturbances has been made at both FRPA and conventional scales of temporal resolution. FRPA study of the late Flandrian II disturbance phase at North Gill 1A showed that cereal cultivation had occurred prior to the Elm Decline as part of a multi-phase period of agricultural land-use activity. The high resolution spatial and temporal data from North Gill have shown FRPA to be a most sensitive palaeoecological technique, and are discussed in relation to the effects of disturbance upon mire and woodland ecosystems, Mesolithic land-use, pre Elm Decline cereal cultivation and early Neolithic land-use

Environmental alteration by mesolithic communities in the north York moors

Palynological and stratigraphic analyses have been conducted at eight sites in two areas of the North York Moors upland, supported in one case by radiocarbon analysis. Attention has been concentrated upon peat deposits of pre-Flandrian III age, in order to elucidate environmental alteration associated with Mesolithic communities in the region. Phases of forest recession apparently caused by fire clearance of the vegetation have been identified at each of these sites, and these have been attributed to the activities of Mesolithic man. The ecological changes associated with these forest clearance events have been illustrated using relative and concentration pollen diagrams, many of which have been drawn using the computer program NEWPLOT devised by Dr. I. Shennan and have involved the use of statistical confidence limits to assist in interpretation of the pollen data. The results of these analyses have been assessed, together with examples of pre-ulmus decline forest recession in the region collated from previously published data. The landscape of the North York Moors during Flandrian I and II has been discussed in terras of its resource potential for human communities, and a number of palaeoenvironmental zones have been identified on this basis. The origin, character and distribution of Menolithic clearance activity in relation to these zones has been discussed, together with its ecological consequences. Finally the role of environmental alteration in Mesolithic economy and land-use in the region and its long-term effects upon the landscape have been considered

Disturbance and succession in early to mid-holocene northern english forests:Palaeoecological evidence for disturbance of woodland ecosystems by mesolithic hunter-gatherers

Forest succession can be monitored in the present, modelled for the future, but also reconstructed in the past on the records of forest history, including through the use of palaeo-ecological techniques. Longer-term records from pollen data can show changes over centennial and millennial timescales that are impacted by climate, migration or soil development. Having knowledge of previous phases of post-disturbance seral stages of woodland regeneration however, as after fire, can provide insights regarding successional process and function over short-term decadal timescales. The aim of this paper is to test the high-resolution pollen record as a source of new insights into processes of succession, assisted by the supplementary data of microscopic charcoal analyses. On short-term timescales, multiple phases of forest disturbance and then recovery have been identified in early to mid-Holocene peat records in northern England, many from the uplands but also from lowland areas. We identify and describe a typology of recovery patterns, including the composition and rate of recovery, and then test the processes and factors that impacted on different seral trajectories, concentrating on fire disturbance which might have had a natural origin, or might have been caused by pre-agricultural Mesolithic hunter-gatherers. Factors considered include the spatial location and intensity of the fire event, the duration of the disturbance phase, the structure and dynamics of the successional regeneration vegetation communities and the pre-disturbance tree cover. Data from examples of fire disturbance of woodland have been examined from both upland and lowland sites in northern England and indicate that they had different successional pathways after disturbance. Fire disturbances in the denser lowland forests were mostly single burn events followed by natural successions and regeneration to forest, whereas fire disturbances in the upland woods usually showed continued or repetitive fire pressure after the initial burning, arresting succession so that vegetation was maintained in a shrub phase, often dominated by Corylus, for an extended period of time until disturbance ceased. This creation of a kind of prolonged, almost plagioclimax, ‘fire-coppice’ hazel stage suggests controlled rather than natural successional pathways, and strongly suggests that Mesolithic foragers were the fire starters in the upland English woodlands where hazel was naturally common and could be maintained in abundance in later-stage successions, along with other edible plants, for human use. All post-fire seral stages would have been attractive to game animals, providing a reliable food source that would have been of great benefit to hunter-gatherer populations

Late Glacial to Holocene relative sea-level change in Assynt, northwest Scotland, UK

Relative sea-level change (RSL), from the Late Glacial through to the late Holocene, is reconstructed for the Assynt region, northwest Scotland, based on bio- and lithostratigraphical analysis. Four new radiocarbon-dated sea-level index points help constrain RSL change for the Late Glacial to the late Holocene. These new data, in addition to published material, capture the RSL fall during the Late Glacial and the rise and fall associated with the mid-Holocene highstand. Two of these index points constrain the Late Glacial RSL history in Assynt for the first time, reconstructing RSL falling from 2.47 ± 0.59 m OD to 0.15 ± 0.59 m OD at c. 14,000–15,000 cal yr BP. These new data test model predictions of glacial isostatic adjustment (GIA), particularly during the early deglacial period which is currently poorly constrained throughout the British Isles. Whilst the empirical data from the mid- to late-Holocene to present matches quite well with the recent GIA model output, there is a relatively poor fit between the timing of the Late Glacial RSL fall and early Holocene RSL rise. This mismatch, also evident elsewhere in northwest Scotland, may result from uncertainties associated with both the global and local ice components of GIA models.</jats:p

Distance-dependent defensive coloration in the poison frog <i>Dendrobates tinctorius</i>, Dendrobatidae

Significance Poison dart frogs are well known for their deadly toxins and bright colors; they are a classic example of warning coloration. However, conspicuousness is not the only consideration; defensive coloration must be effective against a diverse predator community with a variety of different visual systems, and variable knowledge of prey defenses and motivation to attack. We found that the bright colors of Dendrobates tinctorius are highly salient at close-range but blend together to match the background when viewed from a distance. D. tinctorius combines aposematism and camouflage without necessarily compromising the efficacy of either strategy, producing bright colors while reducing encounters with predators. These data highlight the importance of incorporating viewing distance and pattern distribution into studies of signal design. </jats:p

Temporal Coding of Voice Pitch Contours in Mandarin Tones

Accurate perception of time-variant pitch is important for speech recognition, particularly for tonal languages with different lexical tones such as Mandarin, in which different tones convey different semantic information. Previous studies reported that the auditory nerve and cochlear nucleus can encode different pitches through phase-locked neural activities. However, little is known about how the inferior colliculus (IC) encodes the time-variant periodicity pitch of natural speech. In this study, the Mandarin syllable /ba/ pronounced with four lexical tones (flat, rising, falling then rising and falling) were used as stimuli. Local field potentials (LFPs) and single neuron activity were simultaneously recorded from 90 sites within contralateral IC of six urethane-anesthetized and decerebrate guinea pigs in response to the four stimuli. Analysis of the temporal information of LFPs showed that 93% of the LFPs exhibited robust encoding of periodicity pitch. Pitch strength of LFPs derived from the autocorrelogram was significantly (p &lt; 0.001) stronger for rising tones than flat and falling tones. Pitch strength are also significantly increased (p &lt; 0.05) with the characteristic frequency (CF). On the other hand, only 47% (42 or 90) of single neuron activities were significantly synchronized to the fundamental frequency of the stimulus suggesting that the temporal spiking pattern of single IC neuron could encode the time variant periodicity pitch of speech robustly. The difference between the number of LFPs and single neurons that encode the time-variant F0 voice pitch supports the notion of a transition at the level of IC from direct temporal coding in the spike trains of individual neurons to other form of neural representation

High sensitivity of summer temperatures to stratospheric sulfur loading from volcanoes in the Northern Hemisphere

This work was funded by an ERC (European Research Council) Marie Curie Career Integration Grant (CIG14-631752) and a Philip Leverhulme prize in Earth Sciences (PLP-2021-167) from the Leverhulme Trust awarded to A.B. WH is funded by a UKRI Future Leaders Fellowship (MR/S033505/1). M.S. acknowledges the support of the ERC under the European Union’s Horizon 2020 research and innovation programme (grant agreement 820047). H.M.I. and L.C. were both funded by IAPETUS and IAPETUS2 NERC Doctoral Training Partnership. The Tunu2013 and NEEM_2011_S1 ice cores were collected and analyzed for sulfur and other chemical species used to establish the ice core chronologies with funding from NSF grants 1204176 and 0909541 to J.R.M., respectively, and ice cores were sampled with funding from NSF grant 1340174.The 540s, 1450s, and 1600s represent three of the five coldest decades in the Common Era (CE). In each of these cases, the cause of these cold pulses has been attributed to large volcanic eruptions. However, the provenance of the eruption and magnitude of the volcanic forcing remains uncertain. Here, we use high-resolution sulfur isotopes in Greenland and Antarctic ice cores measured across these events to provide a means of improving sulfur loading estimates for these eruptions. In each case, the largest reconstructed tree-ring cooling is associated with an extratropical eruption, and the high-altitude stratospheric sulfate loading of these events is substantially smaller than previous estimates (by up to a factor of two). These results suggest an increased sensitivity of the reconstructed Northern Hemisphere summer temperature response to extratropical eruptions. This highlights the importance of climate feedbacks and processes that amplify and prolong the cooling signal from high latitudes, such as changes in sea ice extent and ocean heat content.Publisher PDFPeer reviewe

Forward to the past: reinventing intelligence-led policing in Britain

Drawing on archival, secondary material and primary research, this paper examines 'Total Policing', the strategy recently adopted by London's Metropolitan Police. It situates that analysis within a critical examination of other innovative policing strategies previously employed in Britain. It argues that the prospects for Total Policing depend upon the resolution of long-standing problems such as: the inadequacy and inefficiency of local intelligence work; the paucity of evidence for the success of commanders' previous efforts to harness together the component parts of their forces in pursuit of a single mission; and, above all, a seeming inability to learn the lessons of the past. © 2013 © 2013 Taylor & Francis