Prices vs quantities with multiple pollutants

We examine the choice of policy instruments (price, quantity or a mix of the two) when two pollutants are regulated and firms' abatement costs are private information. Whether abatement efforts are complements or substitutes is key determining the choice of policies. When pollutants are complements, a mixed policy instrument with a tax on one pollutant and a quota on another is sometimes preferable even if the pollutants are identical in terms of benefits and costs of abatement. Yet, if they are substitutes, the mixed policy is dominated by taxes or quotas.     

Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands

A high-resolution (2-9 year sampling interval) fossil pollen record from the Galápagos Islands, which spans the last 2690 years, reveals considerable ecosystem stability. Vegetation changes associated with independently derived histories of El Ni?o Southern Oscillation variability provided evidence of shifts in the relative abundance of individual species rather than immigration or extinction. Droughts associated with the Medieval Climate Anomaly induced rapid ecological change that was followed by a reversion to the previous state. The paleoecological data suggested nonneutral responses to climatic forcing in this ecosystem prior to the period of human influence. Human impacts on the islands are evident in the record. A marked decline in long-term codominants of the pollen record, Alternanthera and Acalypha, produced a flora without modern analogue before 1930. Intensified animal husbandry after ca. 1930 may have induced the local extinction of Acalypha and Alternanthera. Reductions in populations of grazing animals in the 1970s and 1980s did not result in the return of the native flora, but in invasions by exotic species. After ca. 1970 the trajectory of habitat change accelerated, continuously moving the ecosystem away from the observed range of variability in the previous 2690 years toward a novel ecosystem. The last 40 years of the record also suggest unprecedented transport of lowland pollen to the uplands, consistent with intensified convection and warmer wet seasons.     

Seasonal distribution patterns of juvenile loggerhead sea turtles (<Emphasis Type="Italic">Caretta caretta</Emphasis>) following capture from a shipping channel in the Northwest Atlantic Ocean

Thirty-four juvenile loggerhead sea turtles captured by trawling from the Charleston, South Carolina (USA), shipping channel (32°42′N; −79°47′W) between May 2004 and August 2007 were tagged with satellite transmitters to assess the extent to which they remained near the capture location given their collection along a seasonal migratory corridor. Seventy-five percent of juveniles were classified as seasonal residents. Migrants predominantly swam north in the spring and nomads wandered south in the summer, but predictive indicators for non-resident status were not identified. All but one juvenile generally remained south of 34°N, within 40 km of shore, and in waters <30 m deep throughout the year. Nine of 14 loggerhead sea turtles monitored during the winter remained exclusively over the continental shelf, three briefly occurred in oceanic habitats, and two foraged extensively in oceanic habitats. Residents distributed >15 km from shore between spring and autumn were three times as likely to occur in oceanic habitats in winter. Modest seasonal movements contrasted with adults tagged at similar latitudes and with juveniles tagged further north and suggest distinct foraging groups within a regional foraging ground.     

Distributional patterns of adult male loggerhead sea turtles (<Emphasis Type="Italic">Caretta caretta</Emphasis>) in the vicinity of Cape Canaveral,Florida, USA during and after a major annual breeding aggregation

Satellite transmitters were attached to 25 reproductively active and four inactive adult male loggerhead sea turtles (86.6–107.0 cm SCLmin) captured from the Port Canaveral, FL, USA shipping channel to assess horizontal and vertical distributions. During the breeding period, male loggerheads aggregated (44% of 755 turtle days) in a 117.6 km² core area that encompassed the shipping channel. Median dive duration during the breeding period was 27 min (IQR = 15–42 min) and males spent 4% (IQR = 3–5%) of the time at the surface, with significantly shorter dives associated with reproductively active males. Migrant and resident males dispersed concurrently, with residents shifting > 30 km east across the continental shelf over a more protracted departure schedule than migrants. Dive duration and time spent at the surface increased through the fall. Cluster analysis revealed the strongest association for dive duration with sea state during and after the breeding period, with significantly longer dives during more turbulent conditions. In contrast, univariate associations with surface interval duration were not elucidated.     

Impact of an invasive oak gall wasp on a native butterfly: a test of plant-mediated competition

Phytophagous insects commonly interact through shared host plants. These interactions, however, do not occur in accordance with traditional paradigms of competition, and competition in phytophagous insects is still being defined. It remains unclear, for example, if particular guilds of insects are superior competitors or important players in structuring insect communities. Gall-forming insects are likely candidates for such superior competitors because of their ability to manipulate host plants, but their role as competitors is understudied. We investigate the effect of invasive populations of an oak gall wasp, Neuroterus saltatorius, on a native specialist butterfly, Erynnis propertius, as mediated by their shared host plant, Quercus garryana. This gall wasp occurs at high densities in its introduced range, where we stocked enclosures with caterpillars on trees that varied in gall wasp density. Biomass production of butterflies was lower in enclosures on high-density than on low-density trees because overwintering caterpillars were smaller, and fewer of them eclosed into adults the following spring. To see if the gall wasp induced changes in foliar quality, we measured host plant quality before and after gall induction on 30 trees each at two sites. We found a positive relationship between gall wasp density and the percentage change in foliar C:N, a negative relationship between gall wasp density and the percentage change in foliar water at one site, and no relationship between the percentage change in protein-binding capacity (i.e., phenolics) and gall-wasp density. Additionally, there was a negative relationship between foliar quality and butterfly performance. Our results provide evidence for a plant-mediated impact of an invasive oak gall wasp on a native butterfly and suggest that gall wasps could act as superior competitors, especially when they occur at high densities.     

Oiling the gears of public participation: the value of organisations in establishing Trinity of Voice for communities impacted by the oil and gas industry

With energy crises looming, conflicts over resource extraction and production are on the rise. For communities lacking voice to participate in these conflicts, community-based organisations and local non-governmental organisations help to unite, communicate, and negotiate with other stakeholders. In this paper we compare two cases that demonstrate the roles of organisations in providing voice to citizenry impacted by environmental justice issues. We use Senecah's concept of Trinity of Voice for the purposes of evaluation. These cases provide contrasting examples of how local/regional organisations chose to either expand their organisation's mission to intervene or stick to a strict reading of their mission thus excluding involvement. In both examples we found that organisational involvement, or lack thereof, influenced how citizens were involved in decision-making with one case leading to legislation protecting property owners from industrial activities, and the other leading to a lack of effective involvement and negatively impacted citizens.     

Water quality trends in the Delaware River Basin (USA) from 1980 to 2005

In 1940, the tidal Delaware River was ??one of the most grossly polluted areas in the United States.?? During the 1950s, water quality was so poor along the river at Philadelphia that zero oxygen levels prevented migration of American shad leading to near extirpation of the species. Since then, water quality in the Delaware Basin has improved with implementation of the 1961 Delaware River Basin Compact and 1970s Federal Clean Water Act Amendments. At 15 gages along the Delaware River and major tributaries between 1980 and 2005, water quality for dissolved oxygen, phosphorus, nitrogen, and sediment improved at 39%, remained constant at 51%, and degraded at 10% of the stations. Since 1980, improved water-quality stations outnumbered degraded stations by a 4 to 1 margin. Water quality remains good in the nontidal river above Trenton and, while improved, remains fair to poor for phosphorus and nitrogen in the tidal estuary near Philadelphia and in the Lehigh and Schuylkill tributaries. Water quality is good in heavily forested watersheds (>50%) and poor in highly cultivated watersheds. Water quality recovery in the Delaware Basin is coincident with implementation of environmental laws enacted in the 1960s and 1970s and is congruent with return of striped bass, shad, blue crab, and bald eagle populations.     

Prenatal diagnosis of sex chromosome aneuploidy—What do we tell the prospective parents?

Sex chromosome aneuploidy (SCA) can be detected on prenatal diagnostic testing and cell free DNA screening (cfDNA). High risk cfDNA results should be confirmed with diagnostic testing. This summary article serves as an update for prenatal providers and assimilates data from neurodevelopmental, epidemiologic, and registry studies on the most common SCA. This information can be helpful for counseling after prenatal diagnosis of sex chromosome aneuploidy. Incidence estimates may be influenced by ascertainment bias and this article is not a substitute for interdisciplinary consultation and counseling.     

Climate change collaboration among natural resource management agencies: lessons learned from two US regions

It has been argued that regional collaboration can facilitate adaptation to climate change impacts through integrated planning and management. In an attempt to understand the underlying institutional factors that either support or contest this assumption, this paper explores the institutional factors influencing adaptation to climate change at the regional scale, where multiple public land and natural resource management jurisdictions are involved. Insights from two mid-western US case studies reveal that several challenges to collaboration persist and prevent fully integrative multi-jurisdictional adaptation planning at a regional scale. We propose that some of these challenges, such as lack of adequate time, funding and communication channels, be reframed as opportunities to build interdependence, identify issue-linkages and collaboratively explore the nature and extent of organisational trade-offs with respect to regional climate change adaptation efforts. Such a reframing can better facilitate multi-jurisdictional adaptation planning and management of shared biophysical resources generally while simultaneously enhancing organisational capacity to mitigate negative effects and take advantage of potentially favourable future conditions in an era characterised by rapid climate change.