Determining the drivers of population structure in a highly urbanized landscape to inform conservation planning

Understanding the environmental contributors to population structure is of paramount importance for conservation in urbanized environments. We used spatially explicit models to determine genetic population structure under current and future environmental conditions across a highly fragmented, human‐dominated environment in Southern California to assess the effects of natural ecological variation and urbanization. We focused on 7 common species with diverse habitat requirements, home‐range sizes, and dispersal abilities. We quantified the relative roles of potential barriers, including natural environmental characteristics and an anthropogenic barrier created by a major highway, in shaping genetic variation. The ability to predict genetic variation in our models differed among species: 11–81% of intraspecific genetic variation was explained by environmental variables. Although an anthropogenically induced barrier (a major highway) severely restricted gene flow and movement at broad scales for some species, genetic variation seemed to be primarily driven by natural environmental heterogeneity at a local level. Our results show how assessing environmentally associated variation for multiple species under current and future climate conditions can help identify priority regions for maximizing population persistence under environmental change in urbanized regions.     

Species invasion shifts the importance of predator dependence

The strength of interference between foraging individuals can influence per capita consumption rates, with important consequences for predator and prey populations and system stability. Here we demonstrate how the replacement of a previously established invader, the predatory crab Carcinus maenas, by the recently invading predatory crab Hemigrapsus sanguineus shifts predation from a species that experiences strong predator interference (strong predator dependence) to one that experiences weak predator interference (weak predator dependence). We demonstrate using field experiments that differences in the strength of predator dependence persist for these species both when they forage on a single focal prey species only (the mussel Mytilus edulis) and when they forage more broadly across the entire prey community. This shift in predator dependence with species replacement may be altering the biomass across trophic levels, consistent with theoretical predictions, as we show that H. sanguineus populations are much larger than C. maenas populations throughout their invaded ranges. Our study highlights that predator dependence may differ among predator species and demonstrates that different predatory impacts of two conspicuous invasive predators may be explained at least in part by different strengths of predator dependence.     

Voluntary recycling despite disincentives

This paper assesses the determinants of take-up of a voluntary waste separation scheme, in a scenario where residents sorted, stored and paid for collection of recycling waste even though mixed waste was collected at the kerbside more conveniently, free of charge and without any quantity limits. Uptake of the scheme was positive, persistent and diverse across localities, offering an opportunity to assess the factors determining voluntary participation in the presence of disincentives. We employ a unique panel data-set (n = 4,644) from Malta, including data on recyclable waste kilogrammes collected over the first 86 weeks of the scheme's operation. Drawing on insights from environmental economics and psychology, a model is empirically estimated. Results indicate that uptake is suppressed by the initial constraints households may face and stimulated by collection frequency. Political vote is an important determinant of participation and this interacts with scheme promotion to create diverse uptake rates.     

Variations in jail sentences and the probability of re-arrest for driving while intoxicated

OBJECTIVE: The probability of re-arrest for driving while intoxicated (DWI) is compared for four different groups of individuals classified by whether the individual was convicted and, if so, the type of sentence received. METHOD: Subsequent re-arrests for DWI were examined for all individuals whose index arrest for DWI had occurred between 1994 and 2001 in a county in New Mexico. The groups included (1) those convicted as a result of the index arrest and sentenced to a 28-day jail/treatment program (N (#)=(#) 2,703); (2) all those not convicted as a result of the index arrest (N = 709); (3) those who were convicted but not sentenced to jail (N = 1,047); and (4) those convicted and sentenced to jail (N = 1,290). RESULTS: Adjusting for covariates of BAC, number of prior arrests, ethnicity, age, and sex, the probability of not being re-arrested was greatest among those sentenced to the jail/treatment program (Group 1), next highest in the two groups convicted but not sentenced to jail/treatment (Groups 3 and 4), and lowest in the group that was not convicted (Group 2). Length of jail sentence among people convicted but not sentenced to the jail/treatment program was unrelated to the probability of re-arrest. CONCLUSION: Conviction for DWI, regardless of the sentence, appears to reduce the probability of re-arrest, and being sentenced to a multi-modal treatment/incarceration program further reduces the probability of re-arrest. However, the other types of sentences do not appear to differ in their impact on probability of re-arrest.     

Effects of copper on Sambucus nigra L. seedlings studied by electron paramagnetic resonance and atomic absorption spectroscopies

We present in this work preliminary results on the translocation of copper, manganese and iron from soil to leaves of Sambucus nigra L. seedlings in the presence of increasing copper concentrations in the growth medium. The use of electron spin resonance spectroscopy and the comparison with atomic absorption spectroscopy is not presently common in the study of metal absorption in plants. This approach gave promising results both on the detection of some metal ions, as well as of radical species related to the presence of Cu2+ in plant tissues. Copper was found to act synergistically in manganese uptake.     

Issues and challenges for forest-based carbon-offset projects: A case study of the Noel Kempff climate action project in Bolivia

The Noel Kempff Climate Action Project in Bolivia, nowin its third year, is breaking ground to establishcredible and verifiable methods to quantify greenhousegas (GHG) benefits of land-use change and forestry (LUCF)projects. Developed under the United Nations FrameworkConvention Climate Change (FCCC) Activities ImplementedJointly pilot phase, the project conserves naturalforests that would otherwise have been subjected tocontinued logging and future agricultural conversion.Carbon (C) monitoring began with a C inventory of theproject area in 1997. The total amount of C in theproject area was 118 Tg (Tg = 10¹²g) ± 4%(95% confidence interval). Periodic monitoring ofrelevant C pools (occurring in 1999 and every 5 yrthereafter) occurs over the 30-year life of theproject to establish the difference between thewith-project and projected without-project scenarios. Permanent sample plots were established both insidethe project area to monitor changes in C pools overtime and in a proxy logging concession near theproject area to determine changes in C pools inforests that have been impacted by logging. Ground-based monitoring is complemented by datacollection on forest industry trends and land-usechange patterns. Remote sensing was used to developa vegetation stratification map of the area, and workis ongoing to investigate the potential application ofdual-camera aerial videography to improve theefficiency of monitoring over time.     

Comparison of benthic macroinvertebrate indices for the assessment of the impact of acid mine drainage on an Irish river below an abandoned Cu-S mine

A range of macroinvertebrate indices were compared to assess the most appropriate metric for the assessment of acid mine drainage (AMD) in a low alkalinity, highly erosional river in south-east Ireland. Differences were found in the ability of indices to discriminate AMD impact with the Brillouin, BMWP score, Margalef and Shannon Indices the most precise. Taxon richness was also strongly correlated with AMD indicator parameters (e.g. pH alkalinity, sulphate, Zn and Fe) at impacted sites being an equally reliable metric. The response of the community structure to AMD in this river does not fulfil the optimum criteria for either diversity or biological indices, which may explain the variation in the success of different indices seen in this and other studies. The development of indices that model the expected community response to AMD more accurately or are based on the response of indicator species to AMD pollutants are required.     

Porous silica spheres as indoor air pollutant scavengers

Porous silica spheres were investigated for their effectiveness in removing typical indoor air pollutants, such as aromatic and carbonyl-containing volatile organic compounds (VOCs), and compared to the commercially available polymer styrene-divinylbenzene (XAD-4). The silica spheres and the XAD-4 resin were coated on denuder sampling devices and their adsorption efficiencies for VOCs evaluated using an indoor air simulation chamber. Real indoor sampling was also undertaken to evaluate the affinity of the silica adsorbents for a variety of indoor VOCs. The silica sphere adsorbents were found to have a high affinity for polar carbonyls and found to be more efficient than the XAD-4 resin at adsorbing carbonyls in an indoor environment.     

The Relationship between Extreme Nitrogen Oxide (NOx) Concentrations in Dublin's Atmosphere and Meteorological Conditions

A study was carried out to investigate the effects of meteorological conditions on atmospheric Nitrogen Oxide (NOx (Nitrogen Oxide and Nitrogen Dioxide)) concentrations at a site in Dublin. Data used in the study (meteorological conditions and hourly NOx concentrations) were compiled from hourly records for the years 1988-1992. The research identified wind speed, air pressure and wind direction as the most important meteorological parameters for understanding the behaviour of extreme NOx concentrations in Dublin's air. Daily, weekly and seasonal variation in NOx concentrations were observed. This work also highlighted the importance of the role played by general synoptic weather conditions over local climatic effects in extreme events.