Determination of gasoline range,diesel range,and mineral oil range organics in soils and water by flame lonization gas chromatography

This article describes a method for the determination of gasoline range, diesel range, and mineral oil range organics in soils and water. It represents the culmination of a series of efforts to go beyond typical GRO and DRO methodology currently available in the literature to include a quantitative determination of mineral oil organics having a boiling range up to C₄₄. It also is the result of an attempt to develop a cost‐effective method that enables the analyst to quantify three different types of hydrocarbon components in one GC run under conditions without a concentration step. Method performance is comparable to that of current protocols for GRO and DRO determinations and validated further by comparisons to certified standards and in‐house standards. Accuracy as percentage recovery for GRO in water is 82 to 84 and 91 to 92% for soils. Accuracy as percentage recovery for MRO in water is 84 to 102 and 75 to 80% for soils. Accuracy as percentage recovery for DRO in water is 78 to 100 and 71 to 90% for soils. Results from the analysis of in‐house standards and certified standards for DRO and MRO gave higher recoveries than was demonstrated in the MDL studies. The MDL for DRO in water is 31 mg/l and 14 mg/kg for soils. The MDL for GRO in water is 8 mg/l and 4 mg/kg for soils. For MRO in water, the MDL is 7 mg/l and for soils 10 mg/kg. Future proposed improvements to this method will involve updated software that will allow automatic blank subtraction, automatic calculation of surrogate recoveries and the automatic incorporation of dry weight factors in the final calculations for soils. In addition, a GRO method with a run time of only 24 min will be used routinely when only GRO analyses have to be performed.     

Colonisation dynamics during range expansion is poorly predicted by dispersal in the core range

The potential ranges of many species are shifting due to changing ecological conditions. Where populations become patchy towards the range edge, the realised distribution emerges from colonisation–persistence dynamics. Therefore, a greater understanding of the drivers of these processes, and the spatial scales over which they operate, presents an opportunity to improve predictions of species range expansion under environmental change. Species reintroductions offer an ideal opportunity to investigate the drivers and spatial scale of colonisation dynamics at the range edge. To this effect, we performed and monitored experimental translocations of water voles to quantify how colonisation and local persistence were influenced by habitat quality and occupancy. We used a novel statistical method to simultaneously consider effects across a range of spatial scales. Densely occupied neighbourhoods were highly persistent and frequently colonised. Persistence was more likely in high quality habitat, whereas the influence of habitat quality on colonisation was less clear. Colonisation of suitable habitat in distant, sparsely occupied areas was much less frequent than expected from the well documented high dispersal ability of the species. Persistence of these distant populations was also low, which we attribute to the absence of a rescue effect in sparsely populated neighbourhoods. Our results illustrate a mismatch between the spatial scales of colonisation dynamics in the core and edge of a species’ range, suggesting that recolonisation dynamics in established populations may be a poor predictor of colonisation dynamics at the range edge. Such a mismatch leads to predictions of long lags between the emergence and colonisation of new habitat, with detrimental consequences for a species’ realised distribution, conservation status and contribution to ecosystem function. Conservation translocations that also reinforce existing populations at the range edge might stimulate the rescue effect and mitigate lags in expansion.     

Geographic range limits of species

Understanding the forms that the geographic range limits of species take, their causes and their consequences are key issues in ecology and evolutionary biology. They are also topics on which understanding is advancing rapidly. This themed issue of Proc. R. Soc. B focuses on the wide variety of current research perspectives on the nature and determinants of the limits to geographic ranges. The contributions address important themes, including the roles and influences of dispersal limitation, species interactions and physiological limitation, the broad patterns in the structure of geographic ranges, and the fundamental question of why at some point species no longer evolve the ability to overcome the factors constraining their distributions and thus fail to continue to spread. In this introduction, these contributions are placed in the wider context of these broad themes.     

Marginal range expansion in a host-limited butterfly species Gonepteryx rhamni

1. The British distribution of the butterfly Gonepteryx rhamni (L.) follows closely the range of its natural host plants, Rhamnus catharticus L. and Frangula alnus Miller, suggesting that it is one of the few British butterflies that has a host‐limited distribution. In North Wales, this species has its range margin, and it was recorded only occasionally in a 35‐km² area prior to the 1980s. Frangula alnus bushes were planted in the area in about 1986, allowing the hypothesis that G. rhamni would expand its range following increased host plant availability to be tested. 2. From 1996 to 1998, the distribution of the butterfly and its host plants, R. catharticus (native), Rhamnus alaternus L. (introduced), and F. alnus (introduced to the area but native to Britain), was mapped in the study area. It was found that the butterfly was more widespread than any of its host plants. Frangula alnus was the most widespread of the host plants, and received most eggs, suggesting that the carrying capacity of the habitat would have increased substantially following the planting of this species. Gonepteryx rhamni was able to complete its lifecycle on both introduced species in the study area. 3. A mark–release–recapture study showed that adult G. rhamni moved an average of 512 m, and 50% of movements were further than 400 m; these values are underestimates. The relatively high mobility of this species suggests that it probably perceives host plants and nectar sources as resource patches (patchy population) in this fragmented landscape, and this population now represents a satellite population of the butterfly's main distribution in Britain. 4. The results presented here confirm empirically the host‐limited distribution of G. rhamni, which expanded following the planting of extra host plants.     

A macroevolutionary perspective on species range limits

Understanding the factors that determine the geographic range limits of species is important for many questions in ecology, evolution and conservation biology. These limits arise from complex interactions among ecology and dispersal ability of species and the physical environment, but many of the underlying traits can be conserved among related species and clades. Thus, the range limits of species are likely to be influenced by their macroevolutionary history. Using palaeontological and biogeographic data for marine bivalves, we find that the range limits of genera are significantly related to their constituent species richness, but the effects of age are weak and inconsistent. In addition, we find a significant phylogenetic signal in the range limits at both genus and family levels, although the strength of this effect shows interoceanic variation. This phylogenetic conservatism of range limits gives rise to an evolutionary pattern where wide-ranging lineages have clusters of species within the biogeographic provinces, with a few extending across major boundaries.     

Population genetic analysis of a recent range expansion: mechanisms regulating the poleward range limit in the volcano barnacle Tetraclita rubescens

As range shifts coincident with climate change have become increasingly well documented, efforts to describe the causes of range boundaries have increased. Three mechanisms—genetic impoverishment, migration load, or a physical barrier to dispersal—are well described theoretically, but the data needed to distinguish among them have rarely been collected. We describe the distribution, abundance, genetic variation, and environment of Tetraclita rubescens, an intertidal barnacle that expanded its northern range limit by several hundreds of kilometres from San Francisco, CA, USA, since the 1970s. We compare geographic variation in abundance with abiotic and biotic patterns, including sea surface temperatures and the distributions of 387 co‐occurring species, and describe genetic variation in cytochrome c oxidase subunit I, mitochondrial noncoding region, and nine microsatellite loci from 27 locations between Bahia Magdalena (California Baja Sur, Mexico) and Cape Mendocino (CA, USA). We find very high gene flow, high genetic diversity, and a gradient in physical environmental variation coincident with the range limit. We infer that the primary cause of the northern range boundary in T. rubescens is migration load arising from flow of maladapted alleles into peripheral locations and that environmental change, which could have reduced selection against genotypes immigrating into the newly colonized portion of the range, is the most likely cause of the observed range expansion. Because environmental change could similarly affect all taxa in a region whose distributional limits are established by migration load, these mechanisms may be common causes of range boundaries and largely synchronous multi‐species range expansions.     

Ecological correlates of geographical range occupancy in North American birds

Aim  The degree to which a species is predictably encountered within its range varies tremendously across species. Understanding why some species occur less frequently within their range than others has important consequences for conservation and for analyses of ecological patterns based on range maps. We examined whether patterns in geographical range occupancy can be explained by species-level traits.
Location  North America.
Methods  We used survey data from 1993 to 2002 from the North American Breeding Bird Survey along with digital range maps produced by NatureServe to calculate range occupancy for 298 species of terrestrial birds. We tested whether species traits explained variation in range occupancy values using linear regression techniques.
Results  We found three species traits that together explained more than half of the variation in range occupancy. Population density and niche breadth were positively correlated with occupancy, while niche position was negatively correlated with occupancy.
Main conclusions  Our results suggest that high range occupancy will occur in species that are common at sites on which they occur, that tolerate a relatively wide range of ecological conditions and that tend to have ranges centred on areas with common environmental conditions. Furthermore, it appears that niche-based characteristics may explain patterns of distribution and abundance from local habitats up to the scale of geographical ranges.     

Host range ofFrankia endophytes

Summary Cross-inoculation experiments with 10 pure cultured strains and 17 host species were carried out. The 10 strains were isolated from the root nodules on actinorhizal trees ranging in 9 species, 5 genera and 4 families. The host species belong to 5 genera. The pure cultured strains fromAlnus are of strong ability to infect different species of the same genus. The seedlings inoculated with these strains are able to nodulate normally. These strains can also infect and nodulate the seedlings ofMyrica californica, but not the seedlings of Elaeagnus, Casuarina andMyrica rubra. The pure cultured strains from Elaeagnus can infect and nodulate the host species in the same genus and family with an exception ofE. viridis vardelavayi, which can be only poorly nodulated by a few strains from Elaeagnus. The strains from Elaeagnus cannot infect the seedlings of Alnus andMyrica rubra. The results presented here suggest thatFrankia endophytes can be divided into two groups: Alnus group and Elaeagnus group.     

Adaptation and species range

Phase III of Sewall Wright's shifting-balance process involves the spread of a superior genotype throughout a structured population. However, a number of authors have suggested that this sort of adaptive change is unlikely under biologically plausible conditions. We studied relevant mathematical models, and the results suggest that the concerns about phase III of the shifting-balance process are justified, but only if environmental conditions are stable. If environmental conditions change in a way that alters species range, then phase III can be effective, leading to an enhancement of adaptedness throughout a structured population.     

Range shift promotes the formation of stable range edges

Aim I investigate the counter‐intuitive possibility that range shift promotes the formation of stable range edges. This might be expected because: (1) range‐shifting populations typically evolve increased dispersal on the expanding range edge; (2) increased dispersal steepens the relative slope of environmental gradients (gradients appear steeper to a more dispersive population); and (3) environmental gradients that are steep relative to dispersal encourage the formation of stable range edges (when gradients appear steep, adaptation on the range edge is swamped by maladapted genes). Methods I test the idea that populations take longer to evolve across an environmental gradient when those populations have already undergone a period of spread. I do this using an individual‐based coupled map lattice simulation, in which individuals carry heritable traits for dispersal probability and environment‐specific fitness. Results Numerous simulations across parameter space confirm that a period of range shift almost always results in a longer time to evolve through an environmental gradient. This occurs because of both the mechanism described above and the erosion of adaptive variation resulting from the serial foundering that occurs during range advance. Main conclusions This result suggests that species may often shift their range due to intrinsic changes in the population rather than extrinsic changes in the environment. The result also suggests a new mechanism regulating the speed of invasion, and sounds a cautionary note for climate change impacts: the longer a species tracks climate change, the less able it may be to track that change into the future.     

悬铃木方翅网蝽寄主范围的测定

在室内选择上海地区的19科27种园林植物对悬铃木方翅网蝽Corythucha ciliata(Say)进行寄主专一性测定。非选择性试验结果表明:悬铃木方翅网蝽对一球悬铃木(Platanus occidentalis)、二球悬铃木(Platanus acerifolia)、三球悬铃木(Platanus orientalis)、红叶李(Prunus cerasifera)、构树(Broussonetia papyrifera)和红花槭(Acer rubrum)6种植物有取食现象,其中若虫在前5种植物上取食量较大,而对红花槭只表现为轻微取食;成虫在前4种植物上的取食量较大,而对构树和红花槭只有少量取食。在所有植物中,悬铃木方翅网蝽只能在一球悬铃木、二球悬铃木、三球悬铃木上完成完整的发育世代。选择性试验表明:成虫嗜食一球悬铃木、二球悬铃木、三球悬铃木,部分取食红叶李,而不取食红花槭和构树。成虫产卵显著偏爱于一球悬铃木、二球悬铃木、三球悬铃木,而不在其它植物上产卵。因此,悬铃木方翅网蝽的寄主范围较为单一,只有悬铃木属植物是其寄主。     

Extreme home range sizes among Eurasian lynx at the northern edge of their biogeographic range

Eurasian lynx (Lynx lynx) have a wide distribution across Eurasia. The northern edge of this distribution is in Norway, where they reach up to 72 degrees north. We conducted a study of lynx space use in this region from 2007 to 2013 using GPS telemetry. The home range sizes averaged 2,606 (± 438 SE) km² for males (n = 9 ranges) and 1,456 (± 179 SE) km² for females (n = 24 ranges). These are the largest home ranges reported for any large felid, and indeed are only matched by polar bears, arctic living wolves, and grizzly bears among all the Carnivora. The habitat occupied was almost entirely treeless alpine tundra, with home ranges only containing from 20% to 25% of forest. These data have clear implications for the spatial planning of lynx management in the far north as the current management zones are located in unsuitable habitats and are not large enough to encompass individual lynx movements.     

Extension of dynamic range of sensitive nanoparticle-based immunoassays

Nanoparticles have successfully been employed in immunometric assays that require high sensitivity. Certain analytes, however, require dynamic ranges (DRs) around a predetermined cut-off value. Here, we have studied the effects that antibody orientation and addition of free solid-phase and detection antibodies have on assay sensitivity and DR in traditional sandwich-type immunoassays. D-dimer and cardiac troponin I (cTnI), both routinely used in critical care testing, were applied as model analytes. The assays were performed in microtitration wells with preimmobilized solid-phase antibody. Inherently fluorescent nanoparticles coated with second antibody were used to detect the analyte. The selection of antibody orientation and addition of free solid-phase or detection antibody, with nanoparticles and calibrator, desensitized the assays and extended the DR. With D-dimer the upper limit of the DR was improved from 50 to 10,000 ng/ml, and with cTnI from 25 to 1000 ng/ml. Regression analysis with the Stago STA Liatest D-dimer assay yielded a slope (95% confidence interval) of 0.09 (0.07–0.11) and a y-intercept of −7.79 (−17.87–2.29) ng/L (n = 65, r = 0.906). Thus it is concluded that Europium(III)-chelate-doped nanoparticles can also be employed in immunoassays that require wide DRs around a certain cut-off limit.     

A northward shift of range margins in British Odonata

Many species are predicted to shift their ranges to higher latitudes and altitudes in response to climate warming. This study presents evidence for 37 species of nonmigratory British dragonflies and damselflies shifting northwards at their range margins over the past 40 years, seemingly as a result of climate change. This response by an exemplar group of insects associated with fresh water, parallels polewards range changes observed in terrestrial invertebrates and other taxa.