Soil Moisture and Fungi Affect Seed Survival in California Grassland Annual Plants

Survival of seeds in the seed bank is important for the population dynamics of many plant species, yet the environmental factors that control seed survival at a landscape level remain poorly understood. These factors may include soil moisture, vegetation cover, soil type, and soil pathogens. Because many soil fungi respond to moisture and host species, fungi may mediate environmental drivers of seed survival. Here, I measure patterns of seed survival in California annual grassland plants across 15 species in three experiments. First, I surveyed seed survival for eight species at 18 grasslands and coastal sage scrub sites ranging across coastal and inland Santa Barbara County, California. Species differed in seed survival, and soil moisture and geographic location had the strongest influence on survival. Grasslands had higher survival than coastal sage scrub sites for some species. Second, I used a fungicide addition and exotic grass thatch removal experiment in the field to tease apart the relative impact of fungi, thatch, and their interaction in an invaded grassland. Seed survival was lower in the winter (wet season) than in the summer (dry season), but fungicide improved winter survival. Seed survival varied between species but did not depend on thatch. Third, I manipulated water and fungicide in the laboratory to directly examine the relationship between water, fungi, and survival. Seed survival declined from dry to single watered to continuously watered treatments. Fungicide slightly improved seed survival when seeds were watered once but not continually. Together, these experiments demonstrate an important role of soil moisture, potentially mediated by fungal pathogens, in driving seed survival

R2P–Principle and Practice? The UNSC on Libya

This article explores the international politics regarding Muammar Muhammad Gaddafi's regime and the civil war in Libya in a context of liberalization and democratization of the Arab Spring. The study presents the varying positions taken by the five permanent member states of the UN Security Council, and their levels of adherence to the spirit of Responsible to Protect (R2P). The analysis explores the content of Resolutions 1970 and 1973, and statements made by external parties before, during, and after those resolutions were enacted. It is argued that although R2P has been proclaimed to be a core principle for human security, the Libyan crisis shows much discrepancy and confusion by the international community regarding how that principle should be applied to enduring dictatorial regimes.</p