Total concentrations of mercury in Wisconsin (USA) lakes and rivers

We analyzed surface waters from 30 Wisconsin lakes and rivers for total mercury ([Hg]_T) and total suspended particulates (TSP) on a state-wide basis with trace-metal ‘ultraclean’ techniques. Mercury concentrations ranged from 0.3 to 2.9 ng L^?1 in lakes and from 0.7 to 8.9 ng L^?1 in rivers. TSP concentrations ranged from 0.9 to 6.6 mg L^?1 in lakes and from 3.1 to 31.4 mg L^?1 in rivers. Spatial trends were weak; however, [Hg] _T was generally higher in the spring than in the autumn of 1991. Total mercury concentration was weakly dependent on TSP with the coefficient of determination (r ²) ranging 0.06 to 0.49 across seasonal and geophysical differences.     

Mercury Concentrations in Stream and River Water: An Analytical Framework Applied to Minnesota and Wisconsin (USA)

The total concentration of all mercuryspecies in water, [THg]_w, is a key water qualitymeasure. This paper proposes an analytical framework forthe analysis, interpretation and eventual projection ofstream (and river) [THg]_w. Mercury (Hg) isconceptualized as being distributed among four carriergroups in water: suspended mineral particles, particulateorganic carbon, dissolved organic carbon, and inorganiccomplexes and ions. The conceptual understanding is used asa statistical analytical framework and turned into aquantitative model for Minnesota and Wisconsin based on some1000 data cases from 18 streams (watershed area: 9 ha–115500km²). The resultant model yields a coefficient ofdetermination of 92% for [THg]_w of the fitting datasubset, or 94% for the evaluation subset. Its coefficientshave well defined physical meanings, and are generallyconsistent with independent field measurements from the sameregion or elsewhere. The model provides a comprehensive andquantitative view of the Hg contents of the carriers: thecontents increase with the proportion of watershed area aswetlands or as forests, rise drastically and then fallprecipitously during spring snowmelt, and otherwise peak inthe growing season and reach a minimum in the presence ofsnowpack. The model further reveals that dissolved Hg tendsto increase with emission-related wet sulfate depositionacross the data region.     

Modeling the elemental mercury cycle in Pallette Lake,Wisconsin, USA

The spatial and temporal distribution of elemental Hg (Hg°) and reactive Hg (Hg_R) has been studied on Pallette Lake, Wisconsin during May – August, 1993 and May, 1994. In general, Hg° concentrations near the lake surface greatly exceeded saturation with respect to atmospheric Hg° indicating a flux out (?) of the lake. Evasional losses were estimated using a thin film model and averaged ?101 pmol m^?2 d^?1 during July and August, 1993. A large portion of atmospherically deposited Hg is re-emitted. Thus, in-lake Hg° production' and evasion to the atmosphere will significantly reduce the amount of Hg which is transported to the sediments, the principal site of methylation. Laboratory experiments were conducted to ascertain the rate of Hg° formation from Hg(II). Reduction was significantly lower in heat sterilized lakewater suggesting Hg° production was biologically mediated. The temporal distribution of epilimnetic Hg°, as measured at the lake center, was influenced by Hg° evasion, Hg° production and advective transport of water parcels of differing Hg content. Spatial gradients in Hg° and Hg_R were identified and a transport model was employed to estimate the advective flux of Hg°. The importance of atmospheric deposition and sediment-water interaction as sources of Hg_R to epilimnetic waters were examined. Porewater concentrations of Hg° and Hg_R were determined on several occasions. During May, 1994, the depletion of lakewater Hg_R following a input pulse due to rain was observed and the estimated removal rate (16–20% d^?1) agrees well with reduction rates obtained in the laboratory (23% d^?1).     

Genetic variation in a subterranean arthropod (Folsomia candida) as a method to identify low-permeability barriers in an aquifer

Folsomia candida (order Collembola), a common soil arthropod, has recently been described living in a shallow (2.5–5.7 m below surface), unconsolidated aquifer in southwestern Michigan. F. candida was haplotyped from 14 wells using inter-simple sequence repeats (ISSRs) markers, and genetic variation in F. candida was used as a bioindicator to identify pore scale to mesoscale migration barriers in the aquifer. With one exception, individual haplotypes were only found in single wells. A significant relationship was identified between interpopulation genetic differentiation and geographic distance, and F. candida exhibits genetic population structuring over a very fine geographic scale (0.65 km²). Monmonier's algorithm was used to identify two most likely subsurface barriers to migration. Hypothesized barriers divided the F. candida populations into three genetically distinct groups, with two groups separated by only 15 m. These groupings are not dependent on groundwater flow direction, and are supported by a minimum spanning network and AMOVA analysis. Because F. candida movement is limited by pore size, these barriers identify local areas of low permeability in the aquifer material. The study suggests that F. candida may serve an important role in identifying geological characteristics and patterns in aquifers that may be difficult to evaluate by other means.     

Predicting Recovery from Acidic Deposition: Applying a Modified TAF (Tracking and Analysis Framework) Model to Maine (USA) High Elevation Lakes

We adapted a reduced-form model, built to predict the aquatic effects of alternative nitrogen and sulfur emissions scenarios on Adirondack lakes, New York, for use on high elevation lakes of Maine (HELM), USA. The Tracking and Analysis Framework (TAF) model was originally designed to evaluate the biotic, economic, and health effects of acid deposition. The TAF model developed in our study was used to assess the biotic effects of different levels of sulfate deposition resulting from alternative emissions scenarios. The aquatic portion of the model is based on a lumped-parameter watershed chemistry model, MAGIC (Model of Acidification of Groundwater in Catchments). The original TAF model was built by calibrating MAGIC to 33 lakes in the Adirondack Mountains. We calibrated MAGIC to 78 HELM lakes, and built reduced-form models from these MAGIC predictions. We evaluated TAF predictions of acid neutralizing capacity (ANC), a fish acid stress index (ASI), and the probability of fish presence in 2030 for four different SO₂ emissions-reduction scenarios. The most dramatic emissions reduction scenario produced only modest increases in mean ANC (16.8 μeq/L ± 7.9 μeq/L) and slight increases in mean predicted probability of presence of acid-sensitive fish (0.07± 0.09) across all lakes. However, a small number of lakes were predicted to have more substantial increases in ANC and improvements in other conditions for acid-sensitive fish. Our results reflect the reality that many of the high elevation lakes of Maine historically had low ANC and that some were even acidic in pre-industrial times. Thus, ’recovery’ for most of the high elevation lakes of Maine will be modest under any scenario of reduced acidic deposition.     

Quantifying home range habitat requirements for bobcats (Lynx rufus) in Vermont,USA

We demonstrate how home range and habitat use analysis can inform landscape-scale conservation planning for the bobcat, Lynx rufus, in Vermont USA. From 2005 to 2008, we outfitted fourteen bobcats with GPS collars that collected spatially explicit locations from individuals every 4 h for 3–4 months. Kernel home range techniques were used to estimate home range size and boundaries, and to quantify the utilization distribution (UD), which is a spatially explicit, topographic mapping of how different areas within the home range are used. We then used GIS methods to quantify both biotic (e.g. habitat types, stream density) and abiotic (e.g. slope) resources within each bobcat’s home range. Across bobcats, upper 20th UD percentiles (core areas) had 18% less agriculture, 42% less development, 26% more bobcat habitat (shrub, deciduous, coniferous forest, and wetland cover types), and 33% lower road density than lower UD percentiles (UD valleys). For each bobcat, we used Akaike’s Information Criterion (AIC) to evaluate and compare 24 alternative Resource Utilization Functions (hypotheses) that could explain the topology of the individual’s UD. A model-averaged population-level Resource Utilization Function suggested positive responses to shrub, deciduous, coniferous forest, and wetland cover types within 1 km of a location, and negative responses to roads and mixed forest cover types within 1 km of a location. Applying this model-averaged function to each pixel in the study area revealed habitat suitability for bobcats across the entire study area, with suitability scores ranging between ?1.69 and 1.44, where higher values were assumed to represent higher quality habitat. The southern Champlain Valley, which contained ample wetland and shrub habitat, was a concentrated area of highly suitable habitat, while areas at higher elevation areas were less suitable. Female bobcat home ranges, on average, had an average habitat suitability score of near 0, indicating that home ranges consisted of both beneficial and detrimental habitat types. We discuss the application of habitat suitability mapping and home range requirements for bobcat conservation and landscape scale management.     

Movement of invasive aquatic plants into Minnesota (USA) through horticultural trade

The extent to which invasive aquatic plants move via accidental inclusion in aquatic plant orders or sale of prohibited species is unknown. Forty orders were placed to 34 aquatic plant vendors across the US between May and September 2001 to determine the prevalence of movement into Minnesota via horticultural trade. Federal noxious weeds or Minnesota prohibited exotic species were acquired 92% of the time they were ordered and included Alternanthera sessilis, Butomus umbellata, Hydrocharis morsus-ranae, Potamogeton crispus, and Lythrum salicaria. Ninety three percent of orders received from aquatic plant vendors contained a plant or animal species not specifically requested; 10% of these purchases contained federal noxious weeds or Minnesota exotic species. Lemna minor was the most common incidental receipt found per taxa and per purchase, although Hydrilla verticillata, Lythrum salicaria, Salvinia molesta, and Potamogeton crispus (all prohibited taxa) were also found. Misidentified plants were found in 18% of the orders; unordered seeds in 43%. The sale and transport of prohibited aquatic plants likely presents the greatest risk associated with the aquatic plant trade. Other important factors include misidentification leading to the unintentional sale of invasive plants and the incidental inclusion of species during translocation.     

A preliminary mercury budget for Narragansett Bay (Rhode Island,USA)

The distribution of total Hg (Hg_t) and reactive (Hg_R) in Narragansett Bay, fresh water tributaries and point source discharges was determined during a synoptic survey, carried out in April, 1986. A Hg budget which includes fluvial inputs and atmospheric Hg deposition was constructed and the estuarine behavior of Hg assessed.     

Leaf size variation in subterranean clover (Trifolium subterraneum L. sensu lato)

In subterranean clover, leaf size contributes to plant competitivity; besides, this trait is attributed a diagnostic relevance. The study assessed leaf size variation at two growth stages (60 days after sowing and flowering date) on genotypes belonging to the three main subspecies of the complex, viz. subsp. subterraneum, brachycalycinum, and yanninicum. After 60 days, brachycalycinum showed the largest leaflet area while subterraneum and yanninicum did not differ. Leaf size increase between the two measurements, remarkable in all subspecies, was significantly highest in yanninicum, which showed the largest area at flowering date. The leaflet length/breadth ratio was similar in the three subspecies at both stages. In subterraneum and brachycalycinum this ratio decreased significantly from the first to the second measurement; leaflet area increase seemed depending more on breadth than length increase. Yanninicum showed the longest petiole at flowering, and subspecies ranking for this character paralleled that of leaflet area. Particularly in subterraneum, there was a noticeable genotype variation for all characters. Earlier genotypes tended to have larger leaves after 60 days, and shorter petioles and smaller leaves at flowering date. In subterraneum, the genotype leaflet size decreased on increasing altitude and rainfall, and decreasing temperature of the collection sites. The leaf characters examined fairly confirmed to bear a taxonomic basis. Further assessing the physiological behaviour, particularly the response to defoliation and its agronomic implications, of genotypes characterised by different leaf size is envisageable.     

Natural variation of folate content and composition in spinach (Spinacia oleracea) germplasm

Breeding to increase folate levels in edible parts of plants, termed folate biofortification, is an economical approach to fight against folate deficiency in humans, especially in the developing world. Germplasm with elevated folates are a useful genetic source for both breeding and direct use. Spinach is one of the well-know vegetables that contains a relatively high amount of folate. Currently, little is known about how much folate, and their composition varies in different spinach accessions. The aim of this study was to investigate natural variation in the folate content and composition of spinach genotypes grown under controlled environmental conditions. The folate content and composition in 67 spinach accessions were collected from the United States Department of Agriculture (USDA) and Asian Vegetable Research and Development Center (AVRDC) germplasm collections according to their origin, grown under control conditions to screen for natural diversity. Folates were extracted by a monoenzyme treatment and analyzed by a validated liquid chromatography (LC) method. The total folate content ranged from 54.1 to 173.2 μg/100 g of fresh weight, with 3.2-fold variation, and was accession-dependent. Four spinach accessions (PI 499372, NSL 6095, PI 261787, and TOT7337-B) have been identified as enriched folate content over 150 μg/100 g of fresh weight. The folate forms found were H(4)-folate, 5-CH(3)-H(4)-folate, and 5-HCO-H(4)-folate, and 10-CHO-folic acid also varied among different accessions and was responsible for variation in the total folate content. The major folate vitamer was represented by 5-CH(3)-H(4)-folate, which on average accounted for up to 52% of the total folate pool. The large variation in the total folate content and composition in diverse spinach accessions demonstrates the great genetic potential of diverse genotypes to be exploited by plant breeders.     

Levels and distribution of allozyme and RAPD variation in populations of Elymus fibrosus (Schrenk) Tzvel. (Poaceae)

To study the magnitude and nature of genetic variation in E. fibrosus, the levels and distribution of allozyme and RAPD variations were investigated in populations collected from Finland and Russia. The results obtained from the allozyme and RAPD studies were compared to each other in 10 of the populations. The allozyme analysis showed that 6 of 12 presumed loci (50%) were polymorphic within the species, while the mean number of polymorphic loci within populations was 4.8%. The mean number of allele per locus for the species was 1.5 and 1.05 across the populations. Genetic diversity at the species level was low (H _es = 0.025), and the mean population genetic diversity was even lower (H _ep = 0.007). Both these values were much lower than the average for other Elymus and self-fertilising species. The largest proportion of the total allozyme diversity was found among, rather than within the populations (G _ST = 0.70). The allozyme genetic distances between the populations did not reflect geographic distances. Cluster and principal coordinates analyses revealed the same allozyme relationship patterns among the populations. A comparison of allozyme and RAPD variation in 10 of the populations showed differences in the amount of genetic variation. The RAPD analysis revealed higher levels of variation (A _p = 1.19, P _p = 20.3 and H _ep = 0.09) than the allozyme one) A _p = 1.06, P _p = 5.8 and H _ep = 0.008). For both markers, the largest proportion of the total gene diversity was found among the populations studied (G _st = 0.63 for RAPDs and G _st = 0.65 for allozyme). In contrast to the allozyme analysis, the RAPD based genetic distances did reflect geographic distances. The cluster and principal coordinates analyses showed different grouping of populations for each data set. There was a positive, but not significant, correlation (r = 0.41) between the genetic distance matrices resulting from these markers. Regional comparison revealed that the Finnish populations had a higher diversity than the Russian ones. Generally, this study indicates that E. fibrosus contains low genetic variation in its populations. The results are discussed in the context of conservation of the species.     

Short-range spatial variability of soil physico-chemical variables related to earthworm clustering in a neotropical gallery forest

In this study, we investigated the spatial distribution of an earthworm community together with the heterogeneity of selected soil properties in a gallery forest (GF) of the Colombian “Llanos”. We performed fine-scale spatial variability by intensively sampling 100 points distributed in the nodes of a regular grid with 5 m inter-sample distance. Non-parametric statistics were used and included SADIE analysis and partial Mantel test, in addition to geostatistics (semi-variograms) and correlogram computation. Our results indicated that the spatial distribution of earthworms was characterized by areas of presence (patches) and absence (gaps), although the general pattern was random at the scale of this study (<5 m), while soil physico-chemical characteristics showed a clumped spatial distribution. Contrary to previous results reported for the nearby savanna, a significant spatial association was found for two competing endogeic species Andiodrilus sp. and Glossodrilus sp. in the GF. Semi-variograms of soil environmental factors were adjusted to model families most commonly used (spherical and linear), and correlograms for earthworms showed significant positive and negative spatial autocorrelation for lag distances <15 m and >30 m, respectively. Partial Mantel test revealed specific significant relationships between soil variables and some species. The earthworm community of the GF displayed a random structure in a spatially clumped soil environment, and our results suggested that spatial distribution observed for some species could be the result of preferential selection of soil environmental factors. In other words, soil heterogeneity contributed to the formation of population patches for some earthworm species. The variability of suitable sites (resource availability patchiness) exerted an influence in the spatial distribution of earthworms at the scale used in this study, and we identified the spatial scale at which both environmental heterogeneity could influence and express earthworm impact on soil properties.     

Genotypic diversity and patterns of variation in a germplasm material of Ethiopian mustard (Brassica carinata A. Braun)

The amphidiploid species Brassica carinata A. Braun is believed to have originated in the plateaus of Ethiopia and has been cultivated there as an oilseed crop since antiquity. The species possesses agronomically important genes of rare occurrence. Although there is a large number of collections in Ethiopia, information on the extent of their genetic diversity is very limited. Thirty-six accessions of ecologically diverse regions were tested at three locations and multivariate analyses on 13 morphological and seed characters were performed. There was generally a large amount of divergence in all characters. Geographic isolation of genes, however, was not observed. Both principal component and cluster analyses disclosed complex relationships among the accessions and characters. Accessions with potential genes of interest to improve earliness, yield components and oil and protein contents have been identified. Length of growing period and yield components contributed most for divergence and clustering pattern. Oil, glucosinolate and protein contents also varied among the accessions but not so much between clusters. Increasing protein in high-glucosinolate genotypes reduced oil content and should be more efficient in genotypes of low-glucosinolate genetic background.     

美国玉米产量业务预报方法研究

利用1961 -2006年美国玉米平均单产资料、美国玉米种植区14个代表站玉米生长季逐日平均气温、降水量以及西太平洋月平均海温、北半球500hPa平均高度场环流资料,分别建立了基于地面气象要素、海温、环流资料的美国玉米产量预报模型.利用三种模型分别对1995 -2004年美国玉米平均单产进行预报检验,各模型10a平均预报准确率均在95%以上,但各模型预报准确率波动较大,因此,根据各模型的历史准确率,利用加权方法建立了集合预报模型.2005年、2006年试报结果表明,集合预报模型的准确率均在95%以上,能够满足业务服务的需要.     

Chemotypical variation in Vanilla planifolia Jack. (Orchidaceae) from the Puebla-Veracruz Totonacapan region

One of the threats in the diversity loss of the primary gene pool of Vanilla planifolia is the lack of information on existing level of polymorphism in cultivated germplasm, and the different expressions of this polymorphism. For this reason, it is proposed to study the chemical polymorphism of the four phytochemicals that define the vanilla aroma quality in fruits (vanillin, vanillic acid, p-hydroxybenzaldehyde, p-hydroxybenzoic acid) by HPLC analysis (High Performance Liquid Chromatography) of 25 collections of unknown genotype, grown in the region Totonacapan Puebla-Veracruz, Mexico. The results identified a selection process, domestication in fruit aroma of vanilla, during which increased the participation of vanillin and reduced the presence of three minor compounds (vanillic acid, p-hydroxybenzaldehyde and p-hydroxybenzoic acid) in the global aroma. We distinguished a total of six chemotypes of V. planifolia in the Totonacapan region, some chemotypes with wild aromatic characteristics (low participation of vanillin) related to the material less cultivated in the region and domesticated chemotypes with high participation of vanillin, for the most cultivated material. The results show that the diversification of the chemotypes of V. planifolia is not related to environmental variation. The data indicate that in the possible center of origin of vanilla, there is phytochemical polymorphism, which indirectly suggests the existence of genetic polymorphism, essential for the design of a breeding program for optimizing the use and conservation of diversity of the primary gene pool of Vanilla planifolia.     

Paying for wolves in Solapur, India and Wisconsin, USA: Comparing compensation rules and practice to understand the goals and politics of wolf conservation

With growing pressure for conservation to pay its way, the merits of compensation for wildlife damage must be understood in diverse socio-ecological settings. Here we compare compensation programs in Wisconsin, USA and Solapur, India, where wolves (Canis lupus) survive in landscapes dominated by agriculture and pasture. At both sites, rural citizens were especially negative toward wolves, even though other wild species caused more damage. Wisconsin and Solapur differ in payment rules and funding sources, which reflect distinct conservation and social goals. In Wisconsin, as wolves recolonized the state, some periodically preyed on livestock and hunting dogs. Ranchers and some hunters were more likely to oppose wolves than were other citizens. The Wisconsin compensation program aimed to restore an iconic species by using voluntary contributions from wolf advocates to pay affected individuals more for wolf losses than for other species. By contrast, wolves had been continuously present in Solapur, and damages were distributed amongst the general populace. Government-supported compensation payments were on offer to anyone suffering losses, yet claims registered were low. There were no significant differences in attitudes of any particular segment of the population, but those losing high value livestock applied for compensation. Residents at both sites did not report (Wisconsin) or expect (Solapur) a change in attitude towards wolves as a result of compensation, yet they support the existence of such programs. To assess the merits of any compensation program, one must disentangle the multiple goals of compensation, such as reducing wolf killing or more fairly sharing the costs of conserving large carnivores.     

Genotypic variation in field resistance of Cucurbita pepo cultivars to powdery mildew (Erysiphe cichoracearum)

Summary Fifty-eight cultivars of Cucurbita pepo (mostly zucchini type) were studied in three-year experiments for field resistance to powdery mildew caused by Erysiphe cichoracearum. No genotypes were found with complete resistance to powdery mildew. There were significant differences in the expression of field resistance characterized by some basic epidemiological parameters (maximum infection degree, area below curve). The highest level of field resistance occurred in 13 cultivars including Acceste F1, Albina, ambassador F1, CU-235, Elite F1, Goldfinger, Parmanta F1, Seneca Hybr. F1.Abbreviations ABC area below curve - ID infection degree - CO Cocozelle - VM Vegetable marrow - ZU Zucchini     

Empirical modeling of spatial and temporal variation in warm season nocturnal air temperatures in two North Idaho mountain ranges, USA

Accurate, fine spatial resolution predictions of surface air temperatures are critical for understanding many hydrologic and ecological processes. This study examines the spatial and temporal variability in nocturnal air temperatures across a mountainous region of Northern Idaho. Principal components analysis (PCA) was applied to a network of 70 Hobo temperature loggers systematically distributed across 2 mountain ranges. Four interpretable modes of variability were observed in average nighttime temperatures among Hobo sites: (1) regional/synoptic; (2) topoclimatic; (3) land surface feedback; (4) canopy cover and vegetation. PC time series captured temporal variability in nighttime temperatures and showed strong relationships with regional air temperatures, sky conditions and atmospheric pressure. PC2 captured the topographic variation among temperatures. A cold air drainage index was created by predicting PC2 loadings to elevation, slope position and dissection indices. Nightly temperature maps were produced by applying PC time series back to the PC2 loading surface, revealing complex temporal and spatial variation in nighttime temperatures. Further development of both physically and empirically based daily temperature models that account for synoptic atmospheric controls on fine-scale temperature variability in mountain ecosystems are needed to guide future monitoring efforts aimed at assessing the impact of climate change.