396 research outputs found
Code script (.R file) to generate outputs in 'Conservation implications of a mismatch between data availability and demographic impact'
No full text* file updated 2023/02/21 *
This code reads in the inputs dataset [Nicol-Harper, Alex; Patrick Doncaster, C.; Hilton, Geoff M.; Wood, Kevin; Ezard, Thomas (2022): Inputs (.csv spreadsheets) for 'Conservation implications of a mismatch between data availability and demographic impact'. figshare. Dataset (linked below)] and generates outputs for the pre-print 'Conservation implications of a mismatch between data availability and demographic impact' (DOI: 10.22541/au.165337565.54669681/v1).</p
Status assessment of the Critically Endangered Azores Bullfinch Pyrrhula murina
No full text'This work was part of the Azores Bullfinch monitoring programme included in the project LIFE NAT/P/000013 “Recovery of Azores Bullfinch’s habitat in the Special Protection Area of Pico da Vara / Ribeira do Guilherme”'The Azores Bullfinch is endemic to the island of São Miguel (Azores, Portugal). Its status was uplisted to Critically Endangered in 2005 on the basis of an extremely small and declining population that was considered to be restricted to a very small mountain range (43 km2), in a single location, within which the spread of invasive plants constituted a threat to habitat quality. Nevertheless, information was mostly inferred, or the product of, non-systematic studies. In order to carry out a complete assessment of the conservation status we analysed: (i) population trend, calculated from annual monitoring 1991–2008, (ii) population size, and (iii) range size, obtaining estimates in a single morning study in 2008 involving the simultaneous participation of 48 observers. Contrary to previous inferences, the population is no longer decreasing, although quality of laurel forest habitat continues to decline due to the persistent threat of invasive species. Population size (mean ± SE) was estimated at 1,064 ± 304 individuals using distance sampling methods, although the estimate was very sensitive to the survey method used. Range size estimates (extent of occurrence and area of occupancy) were 144 km2 and 83 km2 respectively. Given the present information, we propose the downlisting of Azores Bullfinch to Endangered on the IUCN Red List.Peer reviewe
Code script (.R file) to generate comparative re-analysis (Appendix D) in 'Conservation implications of a mismatch between data availability and demographic impact'
No full text* file updated 2023/02/21 *
This code re-analyses some existing publications (linked below) for Appendix D of the pre-print 'Conservation implications of a mismatch between data availability and demographic impact' (DOI: 10.22541/au.165337565.54669681/v1) - including reading in of the 'probability matrix.csv' from the pre-print inputs [Nicol-Harper, Alex; Patrick Doncaster, C.; Hilton, Geoff M.; Wood, Kevin; Ezard, Thomas (2022): Inputs (.csv spreadsheets) for 'Conservation implications of a mismatch between data availability and demographic impact'. figshare. Dataset. https://doi.org/10.6084/m9.figshare.16832686.v1].</p
Vital rates of intermittent nonbreeders and returning breeders strongly influence population dynamics of Somateria mollissima (Common Eider)
No full textRisks and costs associated with reproduction may induce iteroparous species to employ intermittent breeding, whereby individuals forgo attempting reproduction in some breeding periods following recruitment to the breeding population. We explore this behavior through population-level analyses of Somateria mollissima (Common Eider), quantifying the survival cost of breeding and hence one benefit of skipping. Nonbreeding in a given year may be a short-term response to expected low fitness returns, avoiding either breeding-induced mortality or low offspring value. Alternatively, or additionally, intermittent breeding may be a long-term strategy maximizing lifetime fitness, with breeding trajectories that include nonbreeding years resulting in more recruited offspring over the whole life course than those with the same number of consecutive breeding attempts. Reanalysis of 3 studies reporting annual mortality schedules for S. mollissima allowed estimation of the proportion of mortality incurred during the peak breeding season (~50%) and hence the difference in survival rates between breeders and nonbreeders. These were incorporated into a life cycle and associated matrix population model with a “refreshed breeder” stage to which individuals transition for the time step following nonbreeding. We show that the transition to this stage strongly influences population growth rate—being more than twice as important as reproduction by continued breeders—mostly driven by the possibility of differential survival after skipping breeding. Our results emphasize the benefits of long-term individual-based studies that can identify refreshed breeders to further our understanding of intermittent breeding. Specifically, the accuracy of population projections could be improved by factoring in transitions following skipped breeding, and management enhanced by interventions facilitating return to the breeding pool, such as nest shelter provision
Conservation implications of a mismatch between data availability and demographic impact
No full textCost-effective use of limited conservation resources requires understanding which data most contribute to alleviating biodiversity declines. Interventions might reasonably prioritise life-cycle transitions with the greatest influence on population dynamics, yet some contributing vital rates are particularly challenging to document. This risks managers making decisions without sufficient empirical coverage of the spatiotemporal variation experienced by the species. Here, we aimed to explore whether the number of studies contributing estimates for a given life-stage transition aligns with that transition's demographic impact on population growth rate, λ. We parameterised a matrix population model using meta-analysis of vital rates for the common eider (Somateria mollissima), an increasingly threatened yet comparatively data-rich species of seaduck, for which some life stages are particularly problematic to study. Female common eiders exhibit intermittent breeding, with some established breeders skipping one or more years between breeding attempts. Our meta-analysis yielded a breeding propensity of 0.72, which we incorporated into our model with a discrete and reversible ‘nonbreeder’ stage (to which surviving adults transition with a probability of 0.28). The transitions between breeding and nonbreeding states had twice the influence on λ than fertility (summed matrix-element elasticities of 24% and 11%, respectively), whereas almost 15 times as many studies document components of fertility than breeding propensity (n = 103 and n = 7, respectively). The implications of such mismatches are complex because the motivations for feasible on-the-ground conservation actions may be different from what is needed to reduce uncertainty in population projections. Our workflow could form an early part of the toolkit informing future investment of finite resources, to avoid repeated disconnects between data needs and availability thwarting evidence-led conservation
Evaluation of the feeder nourishment concept for the Atlantic southeast coast of the United States: A case study for Hilton Head Island, South Carolina
No full textAbout 80-90% of U.S. East Coast barrier beaches have experienced erosion in the last 100 years. South Carolina’s coastline forms no exception, a third of its developed shoreline experiences erosion. Among these eroding shorelines is Hilton Head Island, the second largest barrier island on the U.S. East Coast. Until now, erosion here has been addressed through traditional local beach nourishments. An alternative approach to the traditional nourishment method, are so-called feeder nourishments or feeder beaches. The potential advantages of the feeder nourishment concept over the traditional method are reduction of the nourishment frequency, containment of the ecological stress in a relatively small area, and a short to medium term increase of local available space for recreation and the environment. Given the potential advantages above, the residents of Hilton Head Island asked TU Delft to investigate the possibility of applying a feeder nourishment at their shoreline. Currently, a pilot project known as “The Sand Engine” is examined along the Dutch coast. Several studies into its morphological behaviour show that this feeder nourishment can be beneficial to the sediment budget of a larger coastal cell. Because of the promising results at the Sand Engine pilot project, it is tempting to state that a feeder-nourishment could also be applied at Hilton Head Island. The problem, however, is that the conditions at Hilton Head Island and the Sand Engine are different. There are two main differences between Hilton Head Island and the Sand Engine. First, Hilton Head is subjected to a relative calm wave climate in comparison to the Sand Engine. Second, the presence of two tidal inlets at Hilton Head, compared to a relative straight and uninterrupted coastline at the Sand Engine. As a result, the conclusions drawn from the Sand Engine pilot project do not necessarily hold for Hilton Head Island as well. The main objective of this thesis is to analyse the morphological behaviour of a feeder nourishment located at Hilton Head Island. First, to study its potential as a measure against erosion at Hilton Head. Second, to compare its morphological behaviour to that of the Sand Engine. And third, to be able to examine the potential of the concept for the Atlantic southeast coast of the U.S. in general. The morphological development of a feeder nourishment at Hilton Head Island was simulated with Delft3D over the course of 1 year for different model scenarios, with varying forcing conditions and varying bathymetric features. The effect of the relative calm wave climate at Hilton Head Island in comparison to the Sand Engine is twofold. First, the contribution of wave forcing to the total erosional volume of the feeder nourishment after 1 year is smaller as compared to the Sand Engine. Eliminating all driving forces besides wave forcing reduces the total erosional volume to 58% at Hilton Head, in comparison to 75% at the Sand Engine. Second, the contribution of storm events to the total erosional volume after 1 year from the feeder nourishment is smaller at Hilton Head compared to the Sand Engine. It measures 23% at Hilton Head, in comparison to 60% at the Sand Engine. To assess the impact of the two tidal inlets on the feeder nourishment, they were closed off. Closing of the tidal inlets eliminates any (potential) residual currents. This reduces the total amount of sediment that is eroded from the feeder nourishment by 7% compared to a reference scenario with open tidal inlets. Before construction of the feeder nourishment the coastline south of the nourishment experienced a net sediment outflux of approximately 4000 m3/year. After construction of the feeder nourishment, the southern section experiences a net import of sediment of approximately 100.000 m3/year. Meaning that the southern section, on average, has transitioned from being erosive to accreting. Up to 500 meter away from the nourishment the cross-shore profile shows a seaward movement of the shoreline position of approximately 25 m compared to the original situation without nourishment. Before construction of the feeder nourishment the coastline north of the nourishment experienced a net sediment outflux of approximately 40.000 m3/year. After construction of the feeder nourishment, this net outflux of sediment has decreased to approximately 25.000 m3/year. This shows that the feeder nourishment is feeding sediment to the northern section, but at a rate that is not sufficient to keep up with the underlying erosion rate. The northern domain, on average, still experiences a sediment outflux and stays erosive. Roughly 50 m of coastline directly north of the feeder nourishment experiences a seaward movement of the shoreline position. However, moving further away from the nourishment, the shoreline remains erosive. The Atlantic southeast coast of the United States is made up of North Carolina, South Carolina, Georgia and Florida’s east coast. The South Carolina and Georgia coastline are comparable in both hydrodynamic conditions and geomorphological setting. They are mixed-energy coasts, broken up by numerous tidal inlets, and home to short barrier islands with complex sediment transport patterns. North Carolina’s and Florida’s east coast are wave-dominated, with relative straight shorelines. Which is distinctly differences from the conditions found at Hilton Head Island. Therefore, the potential of the feeder nourishment concept is only analysed for South Carolina’s and Georgia’s coastline. The presence of numerous tidal inlets leads to strongly varying conditions along the coastlines of both states. The developed locations along South Carolina’s coastline that require erosion mitigating measures are south Debidue beach, North Island, Hunting Island and Daufuskie Island. Along Georgia’s coastline there are only some erosion hotspots along Sea Island’s coastline that require erosion mitigation measures. The wave climate at all the above mentioned location is similar to Hilton Head. A southeast swell, with a narrow range of directions and an annual wave height of roughly 1,0 m. The same goes for the tidal range. The results at Hilton Head show that erosion on adjacent coastal sections can be lessened and/or prevented by constructing a feeder nourishment. Given that these locations are subjected to similar conditions, the construction of a feeder nourishment could potentially be an effective measure to prevent or lessen the occurring erosion.Civil Engineering | Hydraulic Engineerin
'The Cloud of Unknowing': its inheritance and its inheritors
No full textThe thesis attempts a portrait of The Cloud in the context of its
position in the history of Christian mysticism. That the
anonymous work owed much to spiritual writers of the preceding
twelve hundred years is not debatable; what it owed maybe
slightly less obvious. The Cloud is essentially a work of
Dionysian mysticism, and various writers within that tradition
who may have influenced or affected the teaching of The Cloud are
examined. At the same time, however, the anonymous writer owes
much to the western tradition of Augustinian theology, and the
role of this, complementary to the Dionysian mysticism, is also
considered. In Chapter II we look at the theological doctrine
underlying the mystical doctrine of the Cloud corpus. Chapter
III has two major parts, both concerned with the influence of
The Cloud on the subsequent development of spiritual writing in
England. The first considers the relationship with Walter
Hilton. The second examines aspects of Puritan thought which may
indicate that the influence of The Cloud, after the Reformation,
was not restricted to Catholic thought
Efficient preservation of young terrestrial organic carbon in sandy turbidity-current deposits
No full text© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hage, S., Galy, V. V., Cartigny, M. J. B., Acikalin, S., Clare, M. A., Grocke, D. R., Hilton, R. G., Hunt, J. E., Lintern, D. G., McGhee, C. A., Parsons, D. R., Stacey, C. D., Sumner, E. J., & Talling, P. J. Efficient preservation of young terrestrial organic carbon in sandy turbidity-current deposits. Geology, 48(9), (2020): 882-887, doi:10.1130/G47320.1.Burial of terrestrial biospheric particulate organic carbon in marine sediments removes CO2 from the atmosphere, regulating climate over geologic time scales. Rivers deliver terrestrial organic carbon to the sea, while turbidity currents transport river sediment further offshore. Previous studies have suggested that most organic carbon resides in muddy marine sediment. However, turbidity currents can carry a significant component of coarser sediment, which is commonly assumed to be organic carbon poor. Here, using data from a Canadian fjord, we show that young woody debris can be rapidly buried in sandy layers of turbidity current deposits (turbidites). These layers have organic carbon contents 10× higher than the overlying mud layer, and overall, woody debris makes up >70% of the organic carbon preserved in the deposits. Burial of woody debris in sands overlain by mud caps reduces their exposure to oxygen, increasing organic carbon burial efficiency. Sandy turbidity current channels are common in fjords and the deep sea; hence we suggest that previous global organic carbon burial budgets may have been underestimated.We thank C. Johnson, M. Lardie, A. Gagnon, A. McNichol, and the NOSAMS (National Ocean Sciences Accelerator Mass Spectrometry) team (Woods Hole Oceanographic Institution [WHOI], Massachusetts, USA) for their help with ramped oxidation system and isotopes. We thank the captain and crew of CCGS Vector. Support was provided by UK Natural Environment Research Council (NERC) grants NE/M007138/1 (to Cartigny) and NE/L013142/1 (to Talling), NE/P005780/1 and NE/P009190/1 (to Clare); a Royal Society Research Fellowship (to Cartigny); an International Association of Sedimentologists Postgraduate Grant and National Oceanography Centre Southampton–WHOI exchange program funds (to Hage); an independent study award from WHOI (to Galy); the Climate Linked Atlantic Sector Science (CLASS) program (NERC grant NE/R015953/1); and the European Research Council under the European Union’s Horizon 2020 research and innovation program (Grant 725955, to Parsons). We thank François Baudin, Xingqian Cui, editor James Schmitt, and three anonymous reviewers
Digestion strategies of North Atlantic seabirds
No full textSIGLEAvailable from British Library Document Supply Centre-DSC:DXN021431 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Vital rate estimates for the common eider Somateria mollissima, a data-rich exemplar of the seaduck tribe
No full textThis database collates vital rate estimates for the common eider (Somateria mollissima), providing a complete demographic parameterization for this slow life‐history species. Monitored across its circumpolar range, the common eider represents a data‐rich exemplar species for the less‐studied seaducks, many of which are under threat.The database contains estimates of the following vital rates: first- year survival; second- year survival; adult annual survival; first breeding (both age‐specific recruitment probability, and breeding propensity across potential recruitment ages); breeding propensity of established female breeders; clutch size; hatching success; and fledging success. These estimates are drawn from 134 studies, across the scientific and grey literature, including three previously inaccessible datasets on clutch size that were contributed in response to a call for data through the IUCN Species Survival Commission's Duck Specialist Group.Although clutch size has been much studied, the contributed datasets have enhanced coverage of studies reported in non‐English languages, which were otherwise only represented when cited in English‐language publications. Breeding propensity has been little studied, perhaps because adult females are often assumed to attempt breeding every year; we obtained a mean breeding propensity of 0.72. Our synthesis highlights the following gaps in data availability: juvenile and male survival; population change; and studies from Russia (at least accessible in English).The database is intended to serve population modellers and scientists involved in the policy and practice of seaduck conservation and management
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