Drought triggers and declarations: science and policy considerations for drought risk management

This paper explores the value of triggers and declarations in the management of drought, bringing together two disciplinary perspectives, those of the public policy scholar and the climate scientist. These two perspectives highlight the complexity of the development and use of triggers in drought risk management by drawing on the experience of the United States, which has the most sophisticated system of drought triggers in the world, and that of Australia that has the most developed and longest standing national drought policy based on principles of risk management. The paper explores the advantages and disadvantages of triggers in managing drought, concluding that triggers are useful risk management tools at the individual level but become problematic and can lead to perverse outcomes when linked to some forms of government support programs.     

Trapping of Rhizophora mangle Propagules by Coexisting Early Successional Species

Distributions of mangroves in coastal wetlands are influenced by abiotic conditions and the net effect of biotic interactions, including competition, facilitation, and consumer pressure. In coastal wetlands, early successional shrubs, herbs, and grasses may facilitate recruitment of mangroves through multiple mechanisms, including amelioration of environmental conditions, propagule trapping, and structural support. In Mosquito Lagoon, FL, we observed an aggregated distribution of Rhizophora mangle propagules along vegetated shorelines with Batis maritima and Sarcocornia perennis and hypothesized that this distribution was a result of propagule trapping by the vegetation. We designed a field experiment to evaluate retention of R. mangle propagules on vegetated and unvegetated shorelines in Mosquito Lagoon. Significant differences were found in the retention time of mangrove propagules at each shoreline type, with vegetated shorelines retaining propagules significantly longer than unvegetated shorelines. Results from this study help to define facilitative mechanisms which may be important in successional processes of coastal wetlands and have direct restoration applications. Successful recovery of mangroves at restoration sites may be facilitated by establishment of B. maritima and S. perennis, when natural propagule sources are available, or through planting mangrove seedlings into existing stands of these halophytes when restoration areas are propagule-limited.     

A spatial statistical analysis of the occurrence of earthquakes along the Red Sea floor spreading: clusters of seismicity

The aim of this study is to apply spatial pattern analysis techniques to a seismic data catalog of earthquakes beneath the Red Sea to try and detect clusters and explore global and local spatial patterns in the occurrence of earthquakes over the years from 1900 to 2009 using a geographical information system (GIS). The spatial pattern analysis techniques chosen for this study were quadrant count analysis, average nearest neighbor, global Moran’s I, Getis–Ord general G, Anselin Local Moran’s I, Getis–Ord Gi*, kernel density estimation, and geographical distributions. Each of these techniques was implemented in the GIS so that computations could be carried out quickly and efficiently. Results showed that (1) these techniques were capable of detecting clusters in the spatial patterns of the occurrence of the earthquakes; (2) both global and local spatial statistics indicate that earthquakes were clustered in the study area beneath the Red Sea; (3) earthquakes with higher magnitudes on the Richter scale were notably concentrated in the central and southern parts of the Red Sea where seismic activities were most active; and (4) earthquakes with moderate magnitudes on the Richter scale were particularly concentrated in the northern part of the Red Sea where there is an area of late-stage continental rifting comprised of a broad trough without a recognizable spreading center, although there were several small, isolated deep troughs. We conclude that the pattern analysis techniques applied to the seismic data catalog of earthquakes beneath the Red Sea could detect clusters in the occurrence of earthquakes from 1900 to 2009.     

Measuring depth of settlement in the red rock lobster,Jasus edwardsii

Settlement of the puerulus stage of Jasus edwardsii (Decapoda: Palinuridae) near the shore takes place over a wide depth range. It occurs intertidally, and, as determined by crevice collectors, also takes place down to depths of at least 50 m. At sites along the east coast of the North Island of New Zealand, depth of greatest settlement found on collectors varied with locality and time, but was within the upper 11.5 m. Surface‐buoyed collectors caught fewer animals than did collectors at greater depths. Settlement levels generally increased with depth to about 10–12 m, then decreased with increasing depth and distance from shore. The ability of/, edwardsii to settle over a wide depth range may improve its chances of recruitment. A device (closing crevice collector) for measuring puerulus settlement of J. edwardsii at depth is described.     

Gomphonema novo‐zelandicum sp. nov., an epiphytic diatom with a specific host preference

Gomphonema novo‐zelandicum sp. nov., the dominant epiphytic diatom on Carpophyllum maschalocarpum and C. flexuosum, growing in the sublittoral fringe zone in northern New Zealand, is described and its taxonomic status determined. This diatom, although present on other macroalgae from the same zone, is predominantly epiphytic on these 2 species of Carpophyllum, maintaining substantial populations on them throughout the year.     

Magnetic field modulated dust streams from Jupiter in interplanetary space

High speed dust streams emanating from near Jupiter were first discovered by the Ulysses spacecraft in 1992. Since then the phenomenon has been re-observed by Galileo in 1995, Cassini in 2000, and Ulysses in 2004. The dust grains are expected to be charged to a potential of , which is sufficient to allow the planet's magnetic field to accelerate them away from the planet, where they are subsequently influenced by the interplanetary magnetic field (IMF). A similar phenomenon was observed near Saturn by Cassini. Here, we report and analyze simultaneous dust, IMF and solar wind data for all dust streams from the two Ulysses Jupiter flybys. We find that compression regions (CRs) in the IMF – regions of enhanced magnetic field – precede most dust streams. Furthermore, the duration of a dust stream is roughly comparable with that of the precedent CR, and the occurrence of a dust stream and the occurrence of the previous CR are separated by a time interval that depends on the distance to Jupiter. The intensity of the dust streams and their precedent CRs are also correlated, but this correlation is only evident at distances from the planet no greater than 2 AU. Combining these observations, we argue that CRs strongly affect dust streams, probably by deflecting dust grain trajectories, so that they can reach the spacecraft and be detected by its dust sensor.     

The COVID-19 pandemic and global environmental change: Emerging research needs

The outbreak of COVID-19 raised numerous questions on the interactions between the occurrence of new infections, the environment, climate and health. The European Union requested the H2020 HERA project which aims at setting priorities in research on environment, climate and health, to identify relevant research needs regarding Covid-19. The emergence and spread of SARS-CoV-2 appears to be related to urbanization, habitat destruction, live animal trade, intensive livestock farming and global travel. The contribution of climate and air pollution requires additional studies. Importantly, the severity of COVID-19 depends on the interactions between the viral infection, ageing and chronic diseases such as metabolic, respiratory and cardiovascular diseases and obesity which are themselves influenced by environmental stressors. The mechanisms of these interactions deserve additional scrutiny. Both the pandemic and the social response to the disease have elicited an array of behavioural and societal changes that may remain long after the pandemic and that may have long term health effects including on mental health. Recovery plans are currently being discussed or implemented and the environmental and health impacts of those plans are not clearly foreseen. Clearly, COVID-19 will have a long-lasting impact on the environmental health field and will open new research perspectives and policy needs.     

A comparison of a GCM response to historical anthropogenic land cover change and model sensitivity to uncertainty in present-day land cover representations

This study assesses the sensitivity of the fully coupled NCAR-DOE PCM to three different representations of present-day land cover, based on IPCC SRES land cover information. We conclude that there is significant model sensitivity to current land cover characterization, with an observed average global temperature range of 0.21 K between the simulations. Much larger contrasts (up to 5 K) are found on the regional scale; however, these changes are largely offsetting on the global scale. These results show that significant biases can be introduced when outside data sources are used to conduct anthropogenic land cover change experiments in GCMs that have been calibrated to their own representation of present-day land cover. We conclude that hybrid systems that combine the natural vegetation from the native GCM datasets combined with human land cover information from other sources are best for simulating such impacts. We also performed a prehuman simulation, which had a 0.39 K ~higher average global temperature and, perhaps of greater importance, temperature changes regionally of about 2 K. In this study, the larger regional changes coincide with large-scale agricultural areas. The initial cooling from energy balance changes appear to create feedbacks that intensify mid-latitude circulation features and weaken the summer monsoon circulation over Asia, leading to further cooling. From these results, we conclude that land cover change plays a significant role in anthropogenically forced climate change. Because these changes coincide with regions of the highest human population this climate impact could have a disproportionate impact on human systems. Therefore, it is important that land cover change be included in past and future climate change simulations.