Flooding and the Distribution of Selected Metals in Floodplain Sediments in St. Maries, Idaho

The link between sediment contamination and flooding is not well established, since flooding may exacerbate problems by spreading pollutants throughout the floodplain, or alternatively may dilute contaminants in source areas. To determine the substance of such relationships, the pattern of sediment contamination was examined in a small Idaho town following flooding in 1996. Four heavy metals were tested, nickel, chromium, zinc and copper, in 97 soil samples obtained from sites across the floodplain of the St. Joe River. Flood history and land-uses at each sample site were noted. Results showed that contamination levels generally were not high, with flood areas having lower concentrations than non-flood areas. A stronger relationship could be argued for land-use, with higher concentrations of contamination associated with some industrial sites. High levels of contamination were also found in several samples taken from recreational areas. Further research looking at the potential sources of contamination in relation to characteristics of the flood hydrology would seem pertinent.     

气候变化对波罗的海入海河流流量的影响

进入波罗的海的河流流量是在一个面积约160万km2的流域中各种不同气候状况下产生的.波罗的海流域气候的变化不仅影响入海淡水的总量,而且对这些水源的分配亦有影响.利用水文模拟,分析了未来气候变化对波罗的海入海径流的影响.使用了瑞典区域气候模拟计划(SWECLIM)中的4种不同的气候变化情景.根据这些不同的气候情景,全部入海河流总的平均年入海量的变化范围为当前入海量的-2%～+15%.波罗的海不同亚区的入海量的变化是大不相同的,其中最剧烈的年均变化范围是-30%～+40%.但是,所有评价的气候情景的共同点是总体趋势为来自波罗的海流域南部地区入海流量减少,北部地区入海量增加.     

Measuring conservation success beyond the traditional biological criteria: the case of conservation projects in Costa Rica,Mekong Valley,and Cameroon

Traditionally, the criteria used to measure conservation success or failure are based on biological factors. Biological factors include changes in the amount of targeted conserved species, biodiversity, and total area conserved. However, conservation efforts are not simply a matter of biological concern; environmental, political, social, and conflict pressures on different scales (ranging from local to global) also have strong influences on the outcome of conservation. These other factors can either pose threats to or enhance conservation, but are not addressed by current criteria. Using a proposed holistic rubric that includes interdisciplinary fields, this paper examines a set of conservation factors on different scales – ranging from local to global – to determine their importance in conservation. The paper analyses positive factor influences with more successful conservation and negative factor influences with less successful, or failed, conservation attempts. Neutral and non‐applicable factor influences are also identified, defined, and ranked as a standardization mechanism. The determination of success changed when the holistic rubric was applied to conservation projects in Costa Rica, Mekong Valley, and Cameroon. In the Costa Rica case study, conservation success for Guanacaste and Talamanca national parks is rated ‘moderately low’. In the case of Mekong Valley, conservation success is rated ‘low’ for Lower Mekong, ‘moderately low’ for Greater Annamites, and ‘low’ for Phong Nha‐Ke Bang national parks. Cameroon's Congo Basin and Sangha Tri‐National conservation efforts are both rated ‘low’, while Dja Faunal is rated ‘very low’. We conclude that if conservation efforts are to attain a high level of success, the strategy for global conservation must move away from the traditional biological approach, which focuses mainly on biological concerns, and embrace a holistic approach, which in addition to biological concerns, addresses environmental, political, social, and conflict pressures, which have strong influences on the outcomes of conservation.     

Characterization of Fugitive Material within a Primary Lead Smelter

ABSTRACT

The primary production of Pb via the sinter plant-blast furnace method resulted in a large number of Pb and other phases, reflecting the complex reactions occurring within each of the processes. Optical microscopy and X-ray diffraction (XRD) techniques have been used to characterize fugitive emissions and dusts generated during sintering, smelting, Cu drossing, refining, and slag fuming at a primary Pb-Zn smelter. The results displayed a complex array of phases, with the mineralogy of the dusts and fume reflecting conditions of the particular metallurgical operation. The principal Pb species followed a transformation from PbS through PbSO₄ and PbO to Pb° (metal) from raw materials to the refinery. The fugitive emissions generated by the blast furnace were of a finer size with more complex chemistry than fugitive material from other source areas. XRD identified a mixture of PbS, ZnO, and ZnS, associated with one or more of the Cl-bearing phases Pb(OH)Cl, PbCl₂, Pb₄O₃Cl₂, Na₃Pb₂(SO₄)₃Cl, Pb₁₀(SO₄)Cl₂O₈, Pb₄SCl₆, and Pb₇S₂Cl₁₀. The presence of Cl-bearing phases in the fume has possible health implications.     

Effects of climate change on species distribution, community structure, and conservation of birds in protected areas in Colombia

Climate change is expected to cause shifts in species distributions worldwide, threatening their viability due to range reductions and altering their representation in protected areas. Biodiversity hotspots might be particularly vulnerable to climate change because they hold large numbers of species with small ranges which could contract even further as species track their optimal habitat. In this study, we assessed the extent to which climate change could cause distribution shifts in threatened and range-restricted birds in Colombia, a megadiverse region that includes the Tropical Andes and Tumbes-Choco-Magdalena hotspots. To evaluate how climate change might influence species in this region, we developed species distribution models using MAXENT. Species are projected to lose on average between 33 and 43 % of their total range under future climate, and up to 18 species may lose their climatically suitable range completely. Species whose suitable climate is projected to disappear occur in mountainous regions, particularly isolated ranges such as the Sierra Nevada de Santa Marta. Depending on the representation target considered, between 46 and 96 % of the species evaluated may be adequately represented in protected areas. In the future, the fraction of species potentially adequately represented is projected to decline to 30–95 %. Additional protected areas may help to retain representativeness of protected areas, but monitoring of species projected to have the largest potential declines in range size will be necessary to assess the need of implementing active management strategies to counteract the effects of climate change.     

Spatiotemporal coupling/decoupling of planktonic larvae and benthic settlement in decapods in the Scottish east coast

Settlement patterns and the relationship between meroplanktonic larvae and settlement in decapods were studied on the Scottish east coast. Artificial settlement substrates (ASS), deployed at two locations (sandy vs. rocky sea substrates), were employed to collect megalopae and newly settled juveniles. Abundance of meroplanktonic larvae was used as an indicator of larval supply. The results showed a clear seasonality in settlement rates, and in some cases, significant differences between sites were detected. Nevertheless, the interference of the ASS with the surrounding habitat limits the study of spatial variability in settlement rates. Significant cross-correlation was found between the abundance of megalopae and juveniles in the collectors and planktonic larval abundance a month earlier. For individual species, this relationship was observed only in Pisidia longicornis. Complexities caused by the great variety of pre- and post-settlement processes, alongside effects of secondary dispersals of early juveniles may have obscured the relationship between meroplanktonic larvae and juveniles in other species.     

Biotic processes in a coastal dunefield: An assessment of seed removal, with non-native seed removal experiments

The impact of granivores on coastal dune seed reserves may be high, increasing along a landward gradient from the littoral zone as the structural complexity of the habitat increases. Seasonal removal rates of non-native seeds by nocturnal and diurnal vertebrates and ants from experimental seed trays in two habitats within the Alexandria Coastal Dunefield, South Africa, were determined. Overall, seed removal was higher in the dune-field bush-pocket habitat than the landward thicket habitat. Nocturnal vertebrates were the most important seed removers within bush-pockets. The importance of nocturnal vertebrates decreased in the thicket and there was a shift in the dominant seed removers to diurnal vertebrates. Seed removal by ants and diurnal vertebrates did not differ significantly between the bush-pockets and thicket while that of nocturnal vertebrates showed a significant change. This can be ascribed to the abundance of the omnivorous murid rodentGerbillurus paeba exilis in the bush-pockets which is absent from thicket vegetation.     

Nitrogen cycling during seven years of atmospheric CO2 enrichment in a scrub oak woodland

Experimentally increasing atmospheric CO2 often stimulates plant growth and ecosystem carbon (C) uptake. Biogeochemical theory predicts that these initial responses will immobilize nitrogen (N) in plant biomass and soil organic matter, causing N availability to plants to decline, and reducing the long-term CO2-stimulation of C storage in N limited ecosystems. While many experiments have examined changes in N cycling in response to elevated CO2, empirical tests of this theoretical prediction are scarce. During seven years of postfire recovery in a scrub oak ecosystem, elevated CO2 initially increased plant N accumulation and plant uptake of tracer 15N, peaking after four years of CO2 enrichment. Between years four and seven, these responses to CO2 declined. Elevated CO2 also increased N and tracer 15N accumulation in the O horizon, and reduced 15N recovery in underlying mineral soil. These responses are consistent with progressive N limitation: the initial CO2 stimulation of plant growth immobilized N in plant biomass and in the O horizon, progressively reducing N availability to plants. Litterfall production (one measure of aboveground primary productivity) increased initially in response to elevated CO2, but the CO2 stimulation declined during years five through seven, concurrent with the accumulation of N in the O horizon and the apparent restriction of plant N availability. Yet, at the level of aboveground plant biomass (estimated by allometry), progressive N limitation was less apparent, initially because of increased N acquisition from soil and later because of reduced N concentration in biomass as N availability declined. Over this seven-year period, elevated CO2 caused a redistribution of N within the ecosystem, from mineral soils, to plants, to surface organic matter. In N limited ecosystems, such changes in N cycling are likely to reduce the response of plant production to elevated CO2.     

The comparative evidence relating to functional and neutral interpretations of biological communities

Neutral and functional theories provide rival interpretations of community patterns involving distribution, abundance, and diversity. One group of patterns describes the overall properties of species or sites, and derives principally from the frequency distribution of abundance among species. According to neutral theory, these patterns are determined by the number of individuals of novel type appearing each generation in the community, whereas functional theory relates them to the distribution of the extent of niches. A second group of patterns describes the spatial attributes of communities, and derives principally from the decay of similarity in species composition with distance. Neutral theory interprets these patterns as consequences of local dispersal alone, whereas the functional interpretation is that more distant sites are likely to be ecologically different. Neutral theory often provides good predictions of community patterns, yet is at variance with a wide range of experimental results involving the manipulation of environments or communities. One explanation for this discrepancy is that spatially explicit models where selection is generally weak, or where selection acts strongly on only a few species at each site, have essentially the same output as neutral models with respect to the distribution of abundance and the decay of similarity. Detecting a non-neutral signal in survey data requires careful spatial or phylogenetic analysis; we emphasize the potential utility of incorporating phylogenetic information in order to detect functional processes that lead to ecological variation among clades.