Drought and grazing combined: Contrasting shifts in plant interactions at species pair and community level

The combined effects of drought stress and grazing pressure on shaping plant–plant interactions are still poorly understood, while this combination is common in arid ecosystems. In this study we assessed the relative effect of grazing pressure and slope aspect (drought stress) on vegetation cover and soil functioning in semi-arid Mediterranean grassland–shrublands in southeastern Spain. Moreover, we linked these two stress factors to plant co-occurrence patterns at species-pair and community levels, by performing C-score analyses. Vegetation cover and soil functioning decreased with higher grazing pressure and more south-facing (drier) slopes. At the community level, plants at south-facing slopes were negatively associated at no grazing but positively associated at low grazing pressure and randomly associated at high grazing pressure. At north-facing slopes, grazing did not result in a shift in the direction of the association. In contrast, analysis of pairwise species co-occurrence patterns showed that the dominant species Stipa tenacissima and Anthyllis cytisoides shifted from excluding each other to co-occurring with increasing grazing pressure at north-facing slopes. Our findings highlight that for improved understanding of plant interactions along stress gradients, interactions between species pairs and interactions at the community level should be assessed, as these may reveal contrasting results.

Potential Shifts in Canadian High Arctic Sedimentary Organic Matter Composition With Permafrost Active Layer Detachments

Increased temperature and precipitation in Arctic regions have led to deeper thawing and structural instability in permafrost soil. The resulting localized disturbances, referred to as active layer detachments (ALDs), may transport organic matter (OM) to more biogeochemically active zones. To examine this further, solid state cross polarization magic angle spinning 13C nuclear magnetic resonance (CPMAS NMR) and biomarker analysis were used to evaluate potential shifts in riverine sediment OM composition due to nearby ALDs within the Cape Bounty Arctic Watershed Observatory, Nunavut, Canada. In sedimentary OM near ALDs, NMR analysis revealed signals indicative of unaltered plant-derived material, likely derived from permafrost. Long chain acyclic aliphatic lipids, steroids, cutin, suberin and lignin occurred in the sediments, consistent with a dominance of plant-derived compounds, some of which may have originated from permafrost-derived OM released by ALDs. OM degradation proxies for sediments near ALDs revealed less alteration in acyclic aliphatic lipids, while constituents such as steroids, cutin, suberin and lignin were found at a relatively advanced stage of degradation. Phospholipid fatty acid analysis indicated that microbial activity was higher near ALDs than downstream but microbial substrate limitation was prevalent within disturbed regions. Our study suggests that, as these systems recover from disturbance, ALDs likely provide permafrost-derived OM to sedimentary environments. This source of OM, which is enriched in labile OM, may alter biogeochemical patterns and enhance microbial respiration within these ecosystems.

Geopolitical shifts in the Eastern Mediterranean. Security Policy Brief No. 43, February 2013

Three major geopolitical events are putting the stability of the Eastern Mediterranean at risk. Most of the region is in a deep monetary and economic crisis. The Arab Spring is causing turmoil in the Levant and the Maghreb. Gas and oil discoveries, if not well managed, could further destabilise the region. At the same time, Russia and Turkey are staging a comeback. In the face of these challenges, the EU approaches the Greek sovereign debt crisis nearly exclusively from a financial and economic viewpoint. This brief argues that the EU has to develop a comprehensive strategy for the region, complementing its existing multilateral regional framework with bilateral agreements in order to secure its interests in the Eastern Mediterranean.

Legal shifts : shaping expectations of intellectual property protection in an open innovation industrial environment

Projet de recherche réalisé en 2014-2015 avec l'appui du Fonds de recherche du Québec – Société et culture.

Citizenship in post-awakening Tunisia: power shifts and conflicting perceptions

With the passing of its new Constitution, Tunisia is rightly celebrated as the Arab state that has advanced the most in strengthening democratic rights provisions. The Constitution formally enshrines the progress Tunisia has made especially on women’s rights; the rights of expression and assembly; freedom of the press; the rights of political parties; and the formal recognition of social and economic rights. However, the Constitution does not definitively resolve tensions between individual and religious rights. In order to maintain consensus between the differing opinions in Tunisia, the document remains ambivalent on the state’s precise role in protecting the ‘sacred’. Tunisia has made much progress, but the Constitution is likely to perpetuate rather than close debates over different concepts of rights.

Citizenship in post-awakening Egypt: power shifts and conflicting perceptions.

This report links Egypt’s shifting political phases to debates more specifically about citizenship rights. It offers a general overview of Egypt’s recent political trajectory, before unpacking the various dimensions of debates over citizenship rights. In each of the three political phases since Mubarak’s ousting, citizenship rights have been curtailed. Crucially, the reasons for their constriction have been different in each phase. Some limitations have derived from largely political power plays, others from more philosophical-theological factors. It is important to distinguish between these different forms of debate if we are better to understand prospects for the future of citizenship rights in Egypt.

Tropically-driven climate shifts in southwestern Europe during MIS 19, a low eccentricity interglacial

The relative roles of high- versus low-latitude forcing of millennial-scale climate variability are still not well understood. Here we present terrestrial–marine climate profiles from the southwestern Iberian margin, a region particularly affected by precession, that show millennial climate oscillations related to a nonlinear response to the Earth's precession cycle during Marine Isotope Stage (MIS) 19. MIS 19 has been considered the best analogue to our present interglacial from an astronomical point of view due to the reduced eccentricity centred at 785 ka. In our records, seven millennial-scale forest contractions punctuated MIS 19 superimposed to two orbitally-driven Mediterranean forest expansions. In contrast to our present interglacial, we evidence for the first time low latitude-driven 5000-yr cycles of drying and cooling in the western Mediterranean region, along with warmth in the subtropical gyre related to the fourth harmonic of precession. These cycles indicate repeated intensification of North Atlantic meridional moisture transport that along with decrease in boreal summer insolation triggered ice growth and may have contributed to the glacial inception, at ∼774 ka. The freshwater fluxes during MIS 19ab amplified the cooling events in the North Atlantic promoting further cooling and leading to MIS 18 glaciation. The discrepancy between the dominant cyclicity observed during MIS 1, 2500-yr, and that of MIS 19, 5000-yr, challenges the similar duration of the Holocene and MIS 19c interglacials under natural boundary conditions.

Legal shifts : shaping expectations of intellectual property protection in an open innovation industrial environment

Projet de recherche réalisé en 2014-2015 avec l'appui du Fonds de recherche du Québec – Société et culture.

Tree line shifts and disturbance events for sites studied in the Torneträsk area of sub-Arctic Sweden for the period 1800-2009

Aim: Models project that climate warming will cause the tree line to move to higher elevations in alpine areas and more northerly latitudes in Arctic environments. We aimed to document changes or stability of the tree line in a sub-Arctic model area at different temporal and spatial scales, and particularly to clarify the ambiguity that currently exists about tree line dynamics and their causes. Location: The study was conducted in the Tornetrask area in northern Sweden where climate warmed by 2.5 °C between 1913 and 2006. Mountain birch (Betula pubescens ssp. czerepanovii) sets the alpine tree line. Methods: We used repeat photography, dendrochronological analysis, field observations along elevational transects and historical documents to study tree line dynamics. Results: Since 1912, only four out of eight tree line sites had advanced: on average the tree line had shifted 24 m upslope (+0.2 m/year assuming linear shifts). Maximum tree line advance was +145 m (+1.5 m/year in elevation and +2.7 m/year in actual distance), whereas maximum retreat was 120 m downslope. Counter-intuitively, tree line advance was most pronounced during the cooler late 1960s and 1970s. Tree establishment and tree line advance were significantly correlated with periods of low reindeer (Rangifer tarandus) population numbers. A decreased anthropozoogenic impact since the early 20th century was found to be the main factor shaping the current tree line ecotone and its dynamics. In addition, episodic disturbances by moth outbreaks and geomorphological processes resulted in descent and long-term stability of the tree line position, respectively. Main conclusions: In contrast to what is generally stated in the literature, this study shows that in a period of climate warming, disturbance may not only determine when tree line advance will occur but if tree line advance will occur at all. In the case of non-climatic climax tree lines, such as those in our study area, both climate-driven model projections of future tree line positions and the use of the tree line position for bioclimatic monitoring should be used with caution.

U.S. trade shifts in selected industries.

"Investigation No. 332-345"--Cover.

Iran-Contra investigation : joint hearings in executive session as declassified before the Senate Select Committee on Secret Military Assistance to Iran and the Nicaraguan opposition and the House Select Committee to Investigate Covert Arms Transactions with Iran, One Hundredth Congress, first session.

Mode of access: Internet.

Iran-Contra investigation : joint hearings before the Senate Select Committee on Secret Military Assistance to Iran and the Nicaraguan Opposition and the House Select Committee to Investigate Covert Arms Transactions with Iran, One Hundredth Congress, first session.

Mode of access: Internet.

Iran-Contra investigation : joint hearings before the House Select Committee to Investigate Covert Arms Transactions with Iran and the Senate Select Committee on Secret Military Assistance to Iran and the Nicaraguan Opposition, One hundredth Congress, first session, 100-8, July 15, 16, 17, 20 and 21, 1987 : testimony of John M. Poindexter.

Mode of access: Internet.

Iran-Contra investigation : joint hearings before the Senate Select Committee on Secret Military Assistance to Iran and the Nicaraguan Opposition and the House Select Committee to Investigate Covert Arms Transactions with Iran, One Hundredth Congress, first session.

Mode of access: Internet.

Iran-Contra investigation : joint hearings before the Senate Select Committee on Secret Military Assistance to Iran and the Nicaraguan Opposition and the House Select Committee to Investigate Covert Arms Transactions with Iran, One Hundredth Congress, first session.

Mode of access: Internet.