1983～1998年间加拿大不列颠哥伦比亚海岸大蓝鹭（Ardea herodias）卵内多氯二苯并-p-二恶英(PCDDs)和二苯并呋喃(PCDFs)的时空趋势监测

从1983~1998年，沿加拿大不列颠哥伦比亚海岸，我们监测了21处大蓝鹭(Ardea herodias)结巢处卵内多氯二苯并-p-二恶英 (PCDDs)、二苯并呋喃(PCDFs) 和多氯联苯 (PCBs)的污染情况。20世纪90年代早期，主要的同类物如1,2,3,7,8-PnCDD、 1,2,3,6,7,8-HxCDD、2,3,7,8-TCDD、2,3,7,8-TCDF、1,2,3,7,8,9-HxCDD 和2,3,4,7,8-PnCDF在纸浆厂分子氯漂白技术被新的漂白技术替代以及氯基酚类木材保存剂和抗木材变色剂的使用被严格地限制之后有显著下降。被捕食的鱼与大蓝鹭卵内污染物水平之间的强正线性回归说明，每天在本地摄食的食物是大蓝鹭暴露于污染物的一个重要路径。从1985年到1991年，在某些栖居地的大蓝鹭卵内所测到的毒当量浓度(TEQs)足以在小鹭体内产生胚胎毒性。尽管PCDD/Fs有所减少，但估计整个80年代有些城市中苍鹭栖居地的毒当量浓度由于多氯联苯的作用而居高不下。     

The Park Made of Oil: Towards a Historical Political Ecology of the Kenneth Hahn State Recreation Area

Within the park-deprived inner-city landscapes of Los Angeles, an unprecedented change is underway. Long considered to be the epitome of anti-nature, Los Angeles is witnessing a boom in park development and ecological restoration. Derelict, blighted and contaminated inner-city brownfield sites are being converted to greenspaces, nature parks and wildlife refuges. Indeed, Los Angeles has been the recent recipient of hitherto unimaginable political and fiscal support to ameliorate the dearth of parks in its neglected urban core. This paper situates the current round of park development within its historical context, by focusing on a very particular local site—the Kenneth Hahn State Recreation Area. Applying the theoretical lens of political ecology, the authors trace some of the political, economic, ecological and institutional factors from the late 1920s onwards, which engendered the creation of a park atop an oilfield. In so doing, the authors deepen the understanding of how local greenspace allocation, poverty, race and political power are oftentimes complexly entangled. Precursor to a much larger project currently in the planning and development stages, the creation of the Kenneth Hahn State Recreation Area reveals some of the ways that the Southern California oil industry has shaped nature spaces in Los Angeles.     

INTEGRATING LANDSCAPE ASSESSMENT AND HYDROLOGIC MODELING FOR LAND COVER CHANGE ANALYSIS1

ABSTRACT: Significant land cover changes have occurred in the watersheds that contribute runoff to the upper San Pedro River in Sonora, Mexico, and southeast Arizona. These changes, observed using a series of remotely sensed images taken in the 1970s, 1980s, and 1990s, have been implicated in the alteration of the basin hydrologic response. The Cannonsville subwatershed, located in the Catskill/Delaware watershed complex that delivers water to New York City, provides a contrast in land cover change. In this region, the Cannonsville watershed condition has improved over a comparable time period. A landscape assessment tool using a geographic information system (GIS) has been developed that automates the parameterization of the Soil and Water Assessment Tool (SWAT) and KINEmatic Runoff and EROSion (KINEROS) hydrologic models. The Automated Geospatial Watershed Assessment (AGWA) tool was used to prepare parameter input files for the Upper San Pedro Basin, a subwatershed within the San Pedro undergoing significant changes, and the Cannonsville watershed using historical land cover data. Runoff and sediment yield were simulated using these models. In the Cannonsville watershed, land cover change had a beneficial impact on modeled watershed response due to the transition from agriculture to forest land cover. Simulation results for the San Pedro indicate that increasing urban and agricultural areas and the simultaneous invasion of woody plants and decline of grasslands resulted in increased annual and event runoff volumes, flashier flood response, and decreased water quality due to sediment loading. These results demonstrate the usefulness of integrating remote sensing and distributed hydrologic models through the use of GIS for assessing watershed condition and the relative impacts of land cover transitions on hydrologic response.     

Closing the Incentive Gap: The Role of Public and Private Actors in Governing Indonesia's Tuna Fisheries

Indonesia is one of the world's largest tuna producing countries, yet regulatory oversight remains weak and management is poor. Incentive-based approaches are a way to improve state-based resource management, but they often require strong government regulation. In this paper, we use principal–agent theory and the notion of the ‘incentive gap’ to explore how incentives could be brought to bear in Indonesia through a combination of private and public actors. With a shared fish stock like tuna, we argue that a double principal–agent problem emerges, where information, asymmetries between various players complicate management. We focus on the problems of adverse selection and moral hazard in three different tuna fisheries in Indonesia to identify the nature of the incentive gap, and comment on the mix of public and private actors currently engaged in tuna fishery governance towards reducing the gap. The double principal–agent problem is a useful yet underutilized framework to understand the dynamics of shared stocks management. In this first application to a developing country fishery, we conclude that information asymmetries cannot be overcome without the involvement of private actors, who are increasingly becoming important in aligning regional and global objectives with those of fishers themselves.     

Advanced driver assistance systems for teen drivers: A national survey of teen and parent perceptions

Abstract

Objective: Recently developed advanced driver assistance systems (ADAS) have the potential to compensate for teen driving errors and reduce overall crash risk. To date, very limited research has been conducted on the suitability of ADAS for teen drivers—the population most likely to benefit from such systems. The opportunity for ADAS to reduce the frequency and severity of crashes involving teen drivers is hindered when there is a lack of trust, acceptance, and use of those technologies. Therefore, there is a need to study teen and parent perceptions of ADAS to help identify and overcome any potential barriers to ADAS use.

Methods: A U.S. national survey was developed based on themes from previously conducted teen and parent ADAS focus groups. Survey topics included trust in ADAS, effect of ADAS on teen driver safety and driving behavior, effect of ADAS on skill development, data privacy, and cybersecurity. Responses included 5-point Likert scales and open-ended questions. The survey was managed through an online respondent panel by ResearchNow. Eligibility criteria included licensed teens (16–19 years) and parents of licensed teens. Teen and parent responses were compared using chi-square statistics in SAS 9.4.

Results: Two thousand and three (teens?=?1,000; parents?=?1,003) respondents qualified for and completed the survey between September 1 and September 20, 2017. Overall, teens (72%) and parents (61%) felt that ADAS would have a positive impact on transportation. However, teens were more likely to exhibit a positive outlook on ADAS, whereas parents were more likely to have a negative outlook (P?<?.01). Teens felt that ADAS would be useful during bad weather or drowsy driving but were less concerned than parents about ADAS intervention during their own risky driving (P?<?.01). The majority of teens (65%) and parents (71%) agreed that teens should learn to drive on vehicles without ADAS, with parents being more likely to agree than teens (P?<?.01). Parents (55%) were more likely than teens (47%) to be concerned about insurance companies keeping track of teen driving data (P?<?.01). Most respondents exhibited some concern of ADAS being susceptible to hacking (57%).

Conclusions: This study represents the first effort to quantify ADAS perceptions among teen drivers and their parents at the U.S. national level. These data highlight potential barriers to ADAS use among teen drivers, including a relative disinterest among teens for ADAS intervention during risky driving as well as concerns among both teens and parents that ADAS will inhibit skill development. These survey findings will help inform educational programs to accelerate fleet turnover and provide the foundation for ADAS optimization and evaluation studies among sociodemographic groups.     

Selection of both habitat and genes in specialized and endangered caribou

Genetic mechanisms determining habitat selection and specialization of individuals within species have been hypothesized, but not tested at the appropriate individual level in nature. In this work, we analyzed habitat selection for 139 GPS-collared caribou belonging to 3 declining ecotypes sampled throughout Northwestern Canada. We used Resource Selection Functions comparing resources at used and available locations. We found that the 3 caribou ecotypes differed in their use of habitat suggesting specialization. On expected grounds, we also found differences in habitat selection between summer and winter, but also, originally, among the individuals within an ecotype. We next obtained Single Nucleotide Polymorphisms (SNPs) for the same caribou individuals, we detected those associated to habitat selection, and then identified genes linked to these SNPs. These genes had functions related in other organisms to habitat and dietary specializations, and climatic adaptations. We therefore suggest that individual variation in habitat selection was based on genotypic variation in the SNPs of individual caribou, indicating that genetic forces underlie habitat and diet selection in the species. We also suggest that the associations between habitat and genes that we detected may lead to lack of resilience in the species, thus contributing to caribou endangerment. Our work emphasizes that similar mechanisms may exist for other specialized, endangered species.     

Simulated interior floods and the flood experience in urban communities

The Hydrologic Engineering Center (HEC-1) model was used to construct synthetic hydrographs for isolated interior urban floods. Flood peak and lag time were very well preserved in simulated flows. Total volume was not adequately expressed. Lag time varied inversely with both urban development and storm intensity. Peak discharge varied with storm intensity, but this variability was well defined only at very high urbanization levels. An 175% increase in storm intensity produced a change of about 15% in peak discharge. Claims for flood damage correlated well with estimates of peak flow and lag time combined. Other measures of flood experience also correlated with the two features. Within the range of storms utilized, urban development factors consistently outranked storm intensity as a determining factor in flood damage.     

A comparison of disposal methods for on-site sewage facilities within the state of Texas,USA

Currently, 1.5 million homes in Texas, USA utilize an on-site sewage facility to manage their household waste. This study compares the conventional septic dispersal technology of perforated pipe drain field with two of the new technologies recently implemented in Texas, multi-pipe and chamber systems, determining if soil classification and climate are influencing factors in functional ability for each of the technologies. There is no statistical significance for failure of a system with respect to system type or climate zone. The textural classification of soil is a statistically significant variable in septic system failures. Soil type III, which includes the clay groups except pure clays and silty clay, appears to significantly influence system failures. Additionally, occupant misuse and lack of maintenance are contributing factors to system failure.     

Differences in the species- and size-composition of fish assemblages in three distinct seagrass habitats with differing plant and meadow structure

Fish faunas were sampled seasonally using a large and a small beam trawl in three seagrass habitats comprising predominantly Amphibolis griffithii or Posidonia sinuosa or Posidonia coriacea, which differ in seagrass and meadow structure. Amphibolis griffithii and P. sinuosa both produce a relatively dense leaf canopy, but the former exhibits a distinct architecture, with the leaf canopy overlying relatively open spaces surrounding woody stems, compared to the uniformly dense blade-like leaves of P. sinuosa which emerge directly from the sediment. In comparison, P. coriacea provides a landscape of patchy seagrass amongst areas of bare sand. Since the latter seagrass habitat contains large areas of sand, fish were also sampled in adjacent unvegetated areas. The number of species and density of fish were greater (P<0.05) in P. sinuosa than in either A. griffithii or P. coriacea. The mean number of species caught using the large trawl ranged from 16 to 24 in the first of these habitats compared to 14–21 and 9–15 in the last two habitats, respectively, and the mean densities ranged between 78 and 291 fish 1000 m^?2 in P. sinuosa compared to 31–59 fish 1000 m^?2 in A. griffithii and 31–59 fish 1000 m^?2 in P. coriacea. The biomass of fish was greater (P<0.05) in both P. sinuosa and A. griffithii than in P. coriacea (4.2–5.3 kg and 3.3–6.2 kg versus 0.7–1.9 kg 1000 m^?2, respectively). Furthermore, the size-structure of fish differed among these habitats, where the median weight of fish was 72.1 g in A. griffithii, compared to 7.5 g and 19.8 g in P. sinuosa and P. coriacea, respectively. Ordination and ANOSIM demonstrated that the species-composition differed markedly among the three seagrass habitats (P<0.001), suggesting that fish species display a distinct preference for particular seagrasses characterised by different architecture. Differences in species-composition among the seagrass habitats partly reflected the size-composition of fish in each habitat. The open space below the canopy of A. griffthii is likely to allow larger fish to occupy this habitat, whereas only small fish would be able to penetrate the dense foliage of P. sinuosa. Differences in species- and size-composition of fish among these habitats may be the result of settlement-sized larvae discriminating between particular seagrass and meadow structures, or fish being subject to different levels of predation and/or accessibility to food or space. The species-composition in P. coriacea was highly dispersed and did not differ from that of unvegetated areas. While several species were associated with both P. coriacea and bare-sand habitats, some species did display a high affinity with the seagrass P. coriacea. This may reflect an association with the sparse and narrower leaves of this seagrass or with the patchy occurrence of the seagrass Heterozostera tasmanica, which commonly occurs as an understorey in this habitat.