Cooling and changing seasonality in the Southern Alps, New Zealand during the Antarctic Cold Reversal

A comprehensively C-14 AMS dated pollen and chironomid record from Boundary Stream Tarn provides the first chironomid-derived temperature reconstruction to quantify temperature change during Lateglacial times (17,500-10,000 cal yr BP) in the Southern Alps, New Zealand. The records indicate a ca 1000-year disruption to the Lateglacial warming trend and an overall cooling consistent with the Antarctic Cold Reversal (ACR). The main interval of chironomid-inferred summer temperature depression (similar to 2-3 degrees C) lasted about 700 years during the ACR. Following this cooling event, both proxies indicate a warming step to temperatures slightly cooler than present during the Younger Dryas chronozone (12,900-11,500 cal yr BP). These results highlight a direct linkage between Antarctica and mid-latitude terrestrial climate systems and the largely asynchronous nature of the interhemispheric climate system during the last glacial transition. The greater magnitude of temperature changes shown by the chironomid record is attributed to the response of the proxies to differences in seasonal climate with chironomids reflecting summer temperature and vegetation more strongly controlled by duration of winter or by minimum temperatures. These differences imply stronger seasonality at times during the Lateglacial, which may explain some of the variability between other paleoclimate records from New Zealand and have wider implications for understanding differences between proxy records for abrupt climate change. (C) 2007 Elsevier Ltd. All rights reserved.

Deconstructing national leadership: Politicians’ accounts of electoral success and failure in the Irish Lisbon Treaty referenda

The Self Categorization approach to national leadership proposes that leaders rhetorically construct national identity as essentialized and inevitable in order to consensualize and mobilize the population. In contrast, discursive studies have demonstrated how national politicians flexibly construct the nation to manage their own accountability in local interactions, though this in turn has neglected broader leadership processes. The present paper brings both approaches together to examine how and when national politicians construct versions of national identity in order to account for their failure as well as success in mobilizing the electorate. Eight semi-structured conversational style interviews were conducted with a strategic sample of eight leading Irish politicians on the subject of the 2008/2009 Irish Lisbon Treaty referenda. Using a Critical Discourse Psychology approach, the hegemonic repertoire of the ‘settled will’
of the informed and consensualized Irish nation was identified across all interviews. Politicians either endorsed the ‘settled will’ repertoire as evidence of their successful leadership, or rejected the repertoire by denying the rationality or unity of the populace to account for their failure. Our results suggest national identity is only constructed as essentialized and inevitable to the extent that it serves a strategic political purpose.

Direct Democracy and Regional Integration::Citizens' Perceptions of Treaty Implications and the Irish Reversal on Lisbon

Analyses of voting in European Union referendums typically distinguish between ‘second-order’ effects and the impact of substantive ‘issues’. In order to explain change in referendum outcome, two types of substantive issues are distinguished in this article. Focusing on Irish voting in the Lisbon Treaty referendums and using data from post-referendum surveys, it is found that perceptions of treaty implications outperform underlying attitudes to EU integration in predicting vote choice at both referendums, and perceptions of treaty implications are strong predictors of vote change between the referendums. The findings have broadly positive implications for normative assessments of the usefulness of direct democracy as a tool for legitimising regional integration advance.

Identifying appropriate sampling and modelling approaches for analysing distributional patterns of Antarctic terrestrial arthropods along the Victoria Land latitudinal gradient

Biotic communities in Antarctic terrestrial ecosystems are relatively simple and often lack higher trophic levels (e. g. predators); thus, it is often assumed that species' distributions are mainly affected by abiotic factors such as climatic conditions, which change with increasing latitude, altitude and/or distance from the coast. However, it is becoming increasingly apparent that factors other than geographical gradients affect the distribution of organisms with low dispersal capability such as the terrestrial arthropods. In Victoria Land (East Antarctica) the distribution of springtail (Collembola) and mite (Acari) species vary at scales that range from a few square centimetres to regional and continental. Different species show different scales of variation that relate to factors such as local geological and glaciological history, and biotic interactions, but only weakly with latitudinal/altitudinal gradients. Here, we review the relevant literature and outline more appropriate sampling designs as well as suitable modelling techniques (e. g. linear mixed models and eigenvector mapping), that will more adequately address and identify the range of factors responsible for the distribution of terrestrial arthropods in Antarctica.

Testing metabolic scaling theory using intraspecific allometries in Antarctic microarthropods

Quantitative scaling relationships among body mass, temperature and metabolic rate of organisms are still controversial, while resolution may be further complicated through the use of different and possibly inappropriate approaches to statistical analysis. We propose the application of a modelling strategy based on the theoretical approach of Akaike's information criteria and non-linear model fitting (nlm). Accordingly, we collated and modelled available data at intraspecific level on the individual standard metabolic rate of Antarctic microarthropods as a function of body mass (M), temperature (T), species identity (S) and high rank taxa to which species belong (G) and tested predictions from metabolic scaling theory (mass-metabolism allometric exponent b = 0.75, activation energy range 0.2-1.2 eV). We also performed allometric analysis based on logarithmic transformations (lm). Conclusions from lm and nlm approaches were different. Best-supported models from lm incorporated T, M and S. The estimates of the allometric scaling exponent linking body mass and metabolic rate resulted in a value of 0.696 +/- 0.105 (mean +/- 95% CI). In contrast, the four best-supported nlm models suggested that both the scaling exponent and activation energy significantly vary across the high rank taxa (Collembola, Cryptostigmata, Mesostigmata and Prostigmata) to which species belong, with mean values of b ranging from about 0.6 to 0.8. We therefore reached two conclusions: 1, published analyses of arthropod metabolism based on logarithmic data may be biased by data transformation; 2, non-linear models applied to Antarctic microarthropod metabolic rate suggest that intraspecific scaling of standard metabolic rate in Antarctic microarthropods is highly variable and can be characterised by scaling exponents that greatly vary within taxa, which may have biased previous interspecific comparisons that neglected intraspecific variability.

Large-scale spatial patterns in the distribution of Collembola (Hexapoda) species in Antarctic terrestrial ecosystems

We tested whether the distribution of three common springtail species (Gressittacantha terranova, Gomphiocephalus hodgsoni and Friesea grisea) in Victoria Land (Antarctica) could be modelled as a function of latitude, longitude, altitude and distance from the sea.

Victoria Land, Ross Dependency, Antarctica.

Generalized linear models were constructed using species presence/absence data relative to geographical features (latitude, longitude, altitude, distance from sea) across the species' entire ranges. Model results were then integrated with the known phylogeography of each species and hypotheses were generated on the role of climate as a major driver of Antarctic springtail distribution.

Based on model selection using Akaike's information criterion, the species' distributions were: hump-shaped relative to longitude and monotonic with altitude for Gressittacantha terranova; hump-shaped relative to latitude and monotonic with altitude for Gomphiocephalus hodgsoni; and hump-shaped relative to longitude and monotonic with latitude, altitude and distance from the sea for Friesea grisea.

No single distributional pattern was shared by the three species. While distributions were partially a response to climatic spatial clines, the patterns observed strongly suggest that past geological events have influenced the observed distributions. Accordingly, present-day spatial patterns are likely to have arisen from the interaction of historical and environmental drivers. Future studies will need to integrate a range of spatial and temporal scales to further quantify their respective roles.

Modelling local-scale determinants and the probability of microarthropod species occurrence in Antarctic soils

Soil fauna in the extreme conditions of Antarctica consists of a few microinvertebrate species patchily distributed at different spatial scales. Populations of the prostigmatic mite Stereotydeus belli and the collembolan Gressittacantha terranova from northern Victoria Land (Antarctica) were used as models to study the effect of soil properties on microarthropod distributions. In agreement with the general assumption that the development and distribution of life in these ecosystems is mainly controlled by abiotic factors, we found that the probability of occurrence of S. belli depends on soil moisture and texture and on the sampling period (which affects the general availability of water); surprisingly, none of the analysed variables were significantly related to the G. terranova distribution. Based on our results and literature data, we propose a theoretical model that introduces biotic interactions among the major factors driving the local distribution of collembolans in Antarctic terrestrial ecosystems. (c) 2007 Elsevier Ltd. All rights reserved.