The Rarest of Darwin's Finches

The Mangrove Finch (Cactospiza heliobates) is unique among Darwin's finches in its specialized habits and naturally fragmented distribution on individual islands. It has been reported to occupy six patches of mangroves separated to varying degrees on two of the Galápagos islands, Isabela and Fernandina. We present the results of a field study in three of the patches. The species appears to have become extinct on Fernandina and to be restricted now to a maximum of four habitat islands on Isabela. In one of them, Playa Tortuga Negra, we estimate the population of breeding adults to be 10–20 pairs. At another, west of Villamil, the population size is probably now small due to the cutting of mangroves. The other two populations, close to each other east of Punta Moreno, probably hold the largest demes. Their status is unknown. We estimate that the genetically effective size of the combined populations is 30–380 individuals. Because the populations are so small and restricted, they are vulnerable to any disturbance of the environment. This has probably been so throughout their history because they inhabit a fragmented habitat in a tectonically active region. New anthropogenic threats this century are an introduced wasp (Polistes versicolor), which may be a predator on a major food item (insect larvae) of the finches, and destruction of the habitat. Protection of the occupied habitat against human exploitation is required for the preservation of the species because no alternative habitat is known.     

Prenatal diagnosis for women aged 37 years and over: to have or not to have

Forty percent of pregnant women aged 37 years and over do not have prenatal diagnosis despite being eligible for a free test. The present study aimed to determine how often, and which, untested women were making a choice about this, how many declined an offer and why. A questionnaire was given to untested women, aged 37 years and over, at no less than 24 weeks gestation. A total of 375 (81.5%) women declined, 72 (16%) were not offered a test and 13 presented too late antenatally. There was a three-fold increased likelihood (OR 3.10 95% CI 1.44, 6.65) of no offer for urban non-English speaking background women, compared with the reference group (metropolitan, English speaking). Unpartnered women were also significantly less likely to receive an offer (OR 3.18, 95% CI 1.19, 8.46). Risk to the baby was the main reason for declining. When offered non-invasive prenatal screening, most decliners of prenatal diagnosis accepted, even those who declined because they were opposed to abortion. We estimate that overall 33% of older pregnant women were being offered and declining amniocentesis and/or chorion villus sampling (CVS). Only 6% were not offered a test, but this small proportion is over-represented by minority groups who must be given equal opportunity to make this choice. Copyright © 2001 John Wiley & Sons, Ltd.     

Apert syndrome: what prenatal radiographic findings should prompt its consideration?

Apert syndrome was diagnosed in a newborn with typical facial and digital features whose only detected prenatal abnormality had been agenesis of the corpus callosum. This prompted a review of the central nervous system findings in all cases of Apert syndrome treated at the Craniofacial Center Boston Children's Hospital between 1978 and 2004. Two of 30 patients with Apert syndrome had prenatal identification of mild dilatation of the lateral cerebral ventricles and complete agenesis of the corpus callosum (ACC) documented with both ultrasound and MRI. Both had the common S252W mutation of FGFR2. Though cranial and orbital malformations typical of Apert were eventually seen in these fetuses in the third-trimester, even in retrospect, these were not detectable at mid second-trimester, ultrasound screening for congenital malformations. Hand malformations also went undetected in the second-trimester despite extensive imaging by experienced radiologists. We conclude that prenatal ultrasonographic identification of mild ventriculomegaly or ACC should stimulate a careful search for features of Apert syndrome and prompt follow-up imaging to look for bony abnormalities that have later onset. Prenatal molecular testing for Apert mutations should be considered in cases of mild ventriculomegaly and ACC. Copyright © 2006 John Wiley & Sons, Ltd.     

Multiple paternity and extra-group fertilizations in a natural population of California grunion (Leuresthes tenuis), a beach-spawning marine fish

Although individuals in many fish species move to shallow waters to spawn, the California grunion (Leuresthes tenuis) is almost unique in its constitutive display of synchronous full-emergence beach spawning. During a spawning event, fish ride large waves onshore to spawn on beach land, where their eggs incubate terrestrially. Here, we employ molecular markers to ascertain how this unusual reproductive behavior impacts genetic parentage. We developed and utilized four highly polymorphic microsatellite markers to assess maternal and paternal contributions in a total of 682 progeny from 17 nests of a natural population of L. tenuis. Alleles deduced to be of paternal origin in progeny were used to determine the minimum number of sires per nest and to estimate the true number of sires per nest via Bayesian analysis. We document the following: (a) no instances of multiple maternity for progeny within a nest; (b) a high frequency of nests (88%) with multiple paternity; and (c) an appreciable fraction of nests (18%) in which the estimated number of genetic sires (as many as nine) proved to be greater than the observed number of male attendants, thus implicating occasional extra-group fertilization events. From these and other observations, we also conclude that spawning behavior in grunions may involve site choice but not explicit mate choice. In addition to providing the first analysis of molecular parentage in a beach-spawning fish, we compare our findings to those reported previously for a beach-spawning arthropod, and we discuss the forces that may be maintaining this peculiar reproductive behavior.     

The use of isomer specific data to characterize and differentiate sources of dioxins into the environment

In a recent comprehensive study of dioxin levels in the environment with several potential historical manufacturing and combustion sources, a simple but effective pattern recognition technique was developed and successfully used to guide the study. Using isomer specific data on 20 tetra isomer groups, the resulting isomer profiles were able to identify dominant sources of dioxin in various areas. Several specific studies and multi-variant statistical procedures were used to confirm the findings.     

Hydrologic evaluation of landfill performance (HELP) modeling in bioreactor landfill design and permitting

The practice of operating municipal solid waste landfills as bioreactor landfills has become more common over the past decade. Because simulating moisture balance and flow is more critical in such landfills than in dry landfills, researchers have developed methods to address this problem using the hydrologic evaluation of landfill performance (HELP) model. This paper discusses three methods of applying the HELP model to simulate the percolation of liquids added to landfill waste: the leachate recirculation feature (LRF), the subsurface inflow (SSI) feature, and additional rainfall to mimic liquids addition. The LRF is simple to use but may not be able to bring the landfill to bioreactor conditions. The SSI feature provides a convenient user interface for modeling liquids addition to each layer. The additional rainfall feature provides flexibility to the model, allowing users to estimate the leachate generation rate and the leachate head on bottom liner associated with daily variation in the liquids addition rate. Additionally, this paper discusses several issues that may affect the HELP model, such as the time of model simulation, layers of liquids addition, and the limitations of the HELP model itself. Based on the simulation results, it is suggested that the HELP model should be run over an extended period of time after the cessation of liquids addition in order to capture the peak leachate generation rate and the head on the liner (HOL). From the perspectives of leachate generation and the HOL, there are few differences between single-layer injection and multiple-layer injection. This paper also discusses the limitations of using the HELP model for designing and permitting bioreactor landfills.     

Climate justice,adaptation and the Paris Agreement: a recipe for disasters?

A Capability Approach is adopted to critically analyse, in the interests of Climate Justice, whether the Paris Agreement is likely to adequately protect human and non-human Capabilities from the worst impacts of climate disasters. The mitigation, adaptation, and loss and damage provisions of the Paris Agreement are not convincing. Adaptation offers only a modest response to climate change, compared with mitigation, and current financial commitments to fund adaptation in developing countries are far too low. Consequently, the Parties to the United Nations Framework Convention on Climate Change have a long way to go in their negotiations before they have any hope of meeting their agreed temperature goals, and protecting human and non-human Capabilities from climate disasters.     

Stream Communities Along a Catchment Land-Use Gradient: Subsidy-Stress Responses to Pastoral Development

When native grassland catchments are converted to pasture, the main effects on stream physicochemistry are usually related to increased nutrient concentrations and fine-sediment input. We predicted that increasing nutrient concentrations would produce a subsidy-stress response (where several ecological metrics first increase and then decrease at higher concentrations) and that increasing sediment cover of the streambed would produce a linear decline in stream health. We predicted that the net effect of agricultural development, estimated as percentage pastoral land cover, would have a nonlinear subsidy-stress or threshold pattern. In our suite of 21 New Zealand streams, epilithic algal biomass and invertebrate density and biomass were higher in catchments with a higher proportion of pastoral land cover, responding mainly to increased nutrient concentration. Invertebrate species richness had a linear, negative relationship with fine-sediment cover but was unrelated to nutrients or pastoral land cover. In accord with our predictions, several invertebrate stream health metrics (Ephemeroptera–Plecoptera–Trichoptera density and richness, New Zealand Macroinvertebrate Community Index, and percent abundance of noninsect taxa) had nonlinear relationships with pastoral land cover and nutrients. Most invertebrate health metrics usually had linear negative relationships with fine-sediment cover. In this region, stream health, as indicated by macroinvertebrates, primarily followed a subsidy-stress pattern with increasing pastoral development; management of these streams should focus on limiting development beyond the point where negative effects are seen.     

Scale-dependence of land use effects on water quality of streams in agricultural catchments

The influence of land use on water quality in streams is scale-dependent and varies in time and space. In this study, land cover patterns and stocking rates were used as measures of agricultural development in two pasture and one native grassland catchment in New Zealand and were related to water quality in streams of various orders. The amount of pasture per subcatchment correlated well to total nitrogen and nitrate in one catchment and turbidity and total phosphorous in the other catchment. Stocking rates were only correlated to total phosphorous in one pasture catchment but showed stronger correlations to ammonium, total phosphorous and total nitrogen in the other pasture catchment. Winter and spring floods were significant sources of nutrients and faecal coliforms from one of the pasture catchments into a wetland complex. Nutrient and faecal coliform concentrations were better predicted by pastural land cover in fourth-order than in second-order streams. This suggests that upstream land use is more influential in larger streams, while local land use and other factors may be more important in smaller streams. These temporal and spatial scale effects indicate that water-monitoring schemes need to be scale-sensitive.