Primer on GRITS/STAT 5.0

GRITS/STAT 4.2 (Groundwater Information Tracking System with statistical analysis capability) enjoys widespread use in the groundwater community. GRITS/STAT is a free PC-based database system capable of performing many of the statistical methods promulgated by the EPA guidance documents: Statistical Analysis of Ground-Water Monitoring Data at RCRA Facilities, 1989, and Addendum to Interim Final Guidance, 1992. GRITS/STAT 4.2, however, suffered from numerous software problems and lagged behind current guidance, particularly in the implementation of statistical intervals. With the release of GRITS/STAT 5.0, many of the software problems that plagued GRITS/STAT 4.2 were addressed and an entirely new Statistical Intervals module was added to bring the software closer to current guidance. The GRITS/STAT 5.0 Beta Test produced a helpful list of work arounds to commonly reported problems. A comparison of the Parametric Confidence Interval methods in GRITS/STAT 4.2 and GRITS/STAT 5.0 illustrates the expanded utility offered by the new Statistics module. The Parametric Confidence Interval in GRITS/STAT 4.2 is only moderately useful for comparing individual wells to an alternate concentration limit (ACL) computed on average background samples. GRITS/STAT 5.0, however, offers users the ability to compare individual and pooled wells to ACLs computed on background averages and risk-based maximum concentration limits (MCLs).     

Effects of interactions between anthropogenic stressors and recurring perturbations on ecosystem resilience and collapse

Insights into declines in ecosystem resilience and their causes and effects can inform preemptive action to avoid ecosystem collapse and loss of biodiversity, ecosystem services, and human well-being. Empirical studies of ecosystem collapse are rare and hampered by ecosystem complexity, nonlinear and lagged responses, and interactions across scales. We investigated how an anthropogenic stressor could diminish ecosystem resilience to a recurring perturbation by altering a critical ecosystem driver. We studied groundwater-dependent, peat-accumulating, fire-prone wetlands known as upland swamps in southeastern Australia. We hypothesized that underground mining (stressor) reduces resilience of these wetlands to landscape fires (perturbation) by diminishing groundwater, a key ecosystem driver. We monitored soil moisture as an indicator of ecosystem resilience during and after underground mining. After landscape fire, we compared responses of multiple state variables representing ecosystem structure, composition, and function in swamps within the mining footprint with unmined reference swamps. Soil moisture declined without recovery in swamps with mine subsidence (i.e., undermined), but was maintained in reference swamps over 8 years (effect size 1.8). Relative to burned reference swamps, burned undermined swamps showed greater loss of peat via substrate combustion; reduced cover, height, and biomass of regenerating vegetation; reduced postfire plant species richness and abundance; altered plant species composition; increased mortality rates of woody plants; reduced postfire seedling recruitment; and extirpation of a hydrophilic animal. Undermined swamps therefore showed strong symptoms of postfire ecosystem collapse, whereas reference swamps regenerated vigorously. We found that an anthropogenic stressor diminished the resilience of an ecosystem to recurring perturbations, predisposing it to collapse. Avoidance of ecosystem collapse hinges on early diagnosis of mechanisms and preventative risk reduction. It may be possible to delay or ameliorate symptoms of collapse or to restore resilience, but the latter appears unlikely in our study system due to fundamental alteration of a critical ecosystem driver. Efectos de las interacciones entre los estresantes antropogénicos y las perturbaciones recurrentes sobre la resiliencia y el colapso de los ecosistemas     

Gypsum addition to soils contaminated by red mud: implications for aluminium, arsenic, molybdenum and vanadium solubility

Red mud is highly alkaline (pH 13), saline and can contain elevated concentrations of several potentially toxic elements (e.g. Al, As, Mo and V). Release of up to 1 million m³ of bauxite residue (red mud) suspension from the Ajka repository, western Hungary, caused large-scale contamination of downstream rivers and floodplains. There is now concern about the potential leaching of toxic metal(loid)s from the red mud as some have enhanced solubility at high pH. This study investigated the impact of red mud addition to three different Hungarian soils with respect to trace element solubility and soil geochemistry. The effectiveness of gypsum amendment for the rehabilitation of red mud-contaminated soils was also examined. Red mud addition to soils caused a pH increase, proportional to red mud addition, of up to 4 pH units (e.g. pH 7 → 11). Increasing red mud addition also led to significant increases in salinity, dissolved organic carbon and aqueous trace element concentrations. However, the response was highly soil specific and one of the soils tested buffered pH to around pH 8.5 even with the highest red mud loading tested (33 % w/w); experiments using this soil also had much lower aqueous Al, As and V concentrations. Gypsum addition to soil/red mud mixtures, even at relatively low concentrations (1 % w/w), was sufficient to buffer experimental pH to 7.5–8.5. This effect was attributed to the reaction of Ca²⁺ supplied by the gypsum with OH^? and carbonate from the red mud to precipitate calcite. The lowered pH enhanced trace element sorption and largely inhibited the release of Al, As and V. Mo concentrations, however, were largely unaffected by gypsum induced pH buffering due to the greater solubility of Mo (as molybdate) at circumneutral pH. Gypsum addition also leads to significantly higher porewater salinities, and column experiments demonstrated that this increase in total dissolved solids persisted even after 25 pore volume replacements. Gypsum addition could therefore provide a cheaper alternative to recovery (dig and dump) for the treatment of red mud-affected soils. The observed inhibition of trace metal release within red mud-affected soils was relatively insensitive to either the percentage of red mud or gypsum present, making the treatment easy to apply. However, there is risk that over-application of gypsum could lead to detrimental long-term increases in soil salinity.     

Stability of a Coal Waste Artificial Reef

The feasibility of using U.K. coal-fired power station waste materials for artificial reef production is being examined. in June, 1989, an experimental artificial reef was constructed in Poole Bay, off the central south coast of the U.K., using three different mixtures of pulverised fuel ash (PFA), flue gas desulphurisation (FGD) gypsum and slurry, stabilized with cement and formed into blocks. Fifty tonnes of 40 × 20 × 20 cm blocks were formed into eight conical reef units replicating three different PFA/gypsum mixtures and one concrete control. the reef structure is 10m below chart datum on a flat sandy sea-bed.

Combustion of coal concentrates the heavy metal content in the resultant ash. the purpose of stabilization of the ash as blocks is twofold: to immobilize heavy metals (or other components) and to provide hard substratum for the attachment of organisms. to examine the effectiveness of this stabilization and hence the environmental compatibility of the block materials, heavy metal (Cd, Cr, Cu, Pb, Mn, Ni, Zn) content of the blocks has been monitored routinely over two years, to determine leaching rates. Sectional profiles indicate partial replacement of calcium content by magnesium. Associated with this there has also been some redistribution of heavy metals. Only in the case of cadmium has there been a detectable loss from the surface of blocks. Chromium and manganese concentrations appear to have increased. the metal content of the reef epibiota (including ascidians, Ascidia mentula; hydroids, Halecium spp.; bryozoans, Bugula spp. and red algae) growing on the ash blocks has been compared to that of epibiota attached to the concrete controls and surrounding sea-bed. to date no evidence of excess bioaccumulation of metals has been detected.

The physical integrity of the ash reef blocks has been maintained. There is evidence that the blocks are increasing in compressive strength.

An indication of the fishery enhancement potential of the experimental structure is given by the presence of eight commercially fished species (crustaceans and molluscs) including lobsters (Homarus gammarus).     

An integrated approach for predicting fates of reintroductions with demographic data from multiple populations

We devised a novel approach to model reintroduced populations whereby demographic data collected from multiple sites are integrated into a Bayesian hierarchical model. Integrating data from multiple reintroductions allows more precise population-growth projections to be made, especially for populations for which data are sparse, and allows projections that account for random site-to-site variation to be made before new reintroductions are attempted. We used data from reintroductions of the North Island Robin (Petroica longipes), an endemic New Zealand passerine, to 10 sites where non-native mammalian predators are controlled. A comparison of candidate models that we based on deviance information criterion showed that rat-tracking rate (an index of rat density) was a useful predictor of robin fecundity and adult female survival, that landscape connectivity and a binary measure of whether sites were on a peninsula were useful predictors of apparent juvenile survival (probably due to differential dispersal away from reintroduction sites), and that there was unexplained random variation among sites in all demographic rates. We used the two best supported models to estimate the finite rate of increase (λ) for populations at each of the 10 sites, and for a proposed reintroduction site, under different levels of rat control. Only three of the reintroduction sites had λ distributions completely >1 for either model. At two sites, λ was expected to be >1 if rat-tracking rates were <5%. At the other five reintroduction sites, λ was predicted to be close to 1, and it was unclear whether growth was expected. Predictions of λ for the proposed reintroduction site were less precise than for other sites because distributions incorporated the full range of site-to-site random variation in vital rates. Our methods can be applied to any species for which postrelease data on demographic rates are available and potentially can be extended to model multiple species simultaneously.     

DIFFERENCES IN WARM-SEASON,RAINSTORM-GENERATED STORMFLOWS FOR NORTHEASTERN ILLINOIS URBANIZED BASINS1

ABSTRACT: Precipitation, streamflow, and population data were analyzed over the 1941–1990 period to determine whether changes in stormflows and net (post. minus pre-rainstorm) stormflows, associated with warm-season large rainstorms, were similar for two urbanized northeastern Illinois basins. Warm season large rainstorms were defined as April through October rainfall events in which ? 5.1 cm occurred in a 48-hour period over the basin. To minimize differences associated with varying large rainstorm amounts over time, the net sthrmflow for each event was divided by the large rainstorm amount. This ratio, Ui, indicated that the two urbanized basins experienced significant, yet different, increases (102 percent and 49 percent) in flow amount per centimeter of rainfall from 1941–1965 to 1966–1990. Results of a regression analysis between Ui and population showed that the increase in U_i per 100,000 increase in population ranged from 0.59 to 0.67 m³s^-1 per cm of rainfall for the two basins. These results demonstrate the varying degree of change that urban planners can expect in stormflows associated with large warm season rainstorms for areas undergoing urbanization.     

Observations on shell form and its ecological significance in thaisid gastropods of the genus Lepsiella in New Zealand

This paper is concerned with the ecological significance of variation in shell form within the thaisid gastropod genus Lepsiella in New Zealand. Shell form has been investigated by measurement of shell height and breadth, aperture length and width, the diameters of consecutive whorls, apical angle, shell weight, and shell capacity, although in many cases shell height and shell breadth could not be measured because of erosion. L.albomarginata has been studied intensively at 4 stations in the South Island, and L. scobina less intensively at 6 stations in the North and South Islands. Comparisons of pairs of characters between stations have been tested by regression analysis and analysis of covariance where appropriate. Shells of L. albomarginata are relatively taller and narrower, and have a thicker wall, at a very sheltered station (Hakahaka Bay) that at more wave-exposed stations. L. scobina (sensu stricto), characterised by the presence of spiral ribs on the shell, exhibits less striking but comparable differences in shell shape. In laboratory tests in a tidal tank the thicker-shelled L. albomarginata from a sheltered station (Hakahaka Bay in Port Underwood) was much better able to resist attack by the shore crab Hemigrapsus edwardsi than was L. albomarginata from a nearby wave-exposed station (Whites Bay, near Cape Campbell, South Island). L. scobina from both stations was resistant to attack. H. edwardsi abounds at sheltered stations, but is missing from wave-exposed rock reefs such as those at Whites Bay, so that the ability to survive encounters with shore crabs is ecologically important to L. albomarginata inhabiting sheltered stations. L. scobina occupies a lower zone on the shore, where it is probably liable to encounter other more powerful predators. Its spiral ribs probably strengthen the shell. We do not know to what extent differences in shell form and thickness depend on environmental factors, and to what extent they originate genetically. Thin shells are associated with an abundance of mussels (Mytilus edulis ssp. aoteanus or Modiolus neozelanicus). There is an interesting possibility that a scarcity of mussels or other food caused by superior nonspecific predators might result in the production of better-protected Lepsiella.     

Using Taxonomy to Predict Success among Introduced Avifauna: Relative Importance of Transport and Establishment

Abstract: For invasion ecology to become a quantitative approach to conservation, robust predictors of success must be identified. Taxonomy, although often casually mentioned, has never been thoroughly assessed as an agent of prediction. I used binomial probabilities to identify taxonomic patterns in establishment success among global avifauna. At most, 2.54% of all avian species are considered successfully established exotics somewhere in the world. The distribution of these species among higher taxa is far from random. Seven families contained more successfully established exotic species than expected by chance: Anatidae (ducks and geese), Phasianidae (pheasants), Passeridae (sparrows and estrildid finches), Psittacidae (parrots and allies), Columbidae (pigeons and doves), Rheidae (rheas), and Odontophoridae (New World quails). Human influence on probability of transport appears to drive this taxonomic pattern. Anatidae, Odontophoridae, and Phasianidae hold far more species than expected that arrived in their invasive range for exploitation (i.e., hunting or game). Passeridae and Sturnidae (starlings and mynahs) have more pet species than expected by chance. Thus, traits that enhance probability of purposeful transport exhibit a taxonomic pattern. This human influence on probability of transport increases the quantity of species introduced but does not increase the proportion of species that successfully become established. When invasion risk is assigned, it is vital to understand the interaction between species-specific attributes that influence establishment and transportation.     

Right-wing populism and the climate change agenda: exploring the linkages

The rise of right-wing populism (RWP) poses a challenge for the climate agenda, as leaders and supporters tend to be climate sceptics and hostile to policy prescribing action on climate change. However, there is a surprising dearth of research that investigates the nature and causes of this association. Two kinds of explanation are considered, drawing on the literature on populism. One is termed ‘structuralist’, drawing on accounts of the roots of populism in economic and political marginalisation amongst those ‘left behind’ by globalisation and technological change. A second focuses on the ideological content of RWP, especially its antagonism between ‘the people’ and a cosmopolitan elite, with climate change and policy occupying a symbolic place in this contrast. It is argued that there are limits to the structuralist approach, and that an ideologically based explanation is more compelling. An agenda for future research on RWP and climate science and policy is proposed.