Mobility of dimethoate residues from spring broccoli field

Dimethoate [O, O-dimethyl-S-(N-methylcarbamoyl-methyl) phosphorodithioate] is a broad-spectrum systemic insecticide currently used worldwide and on many vegetables in Kentucky. Dimethoate is a hydrophilic compound (log KOW = 0.7) and has the potential of offsite movement from the application site into runoff and infiltration water. The dissipation patterns of dimethoate residues were studied on spring broccoli leaves and heads under field conditions. Following foliar application of Dimethoate 4E on broccoli foliage at the rate of 0.47 L acre(-1), dimethoate residues were monitored in soil, runoff water collected down the land slope, and in infiltration water collected from the vadose zone. The study was conducted on a Lowell silty loam soil (pH 6.9) planted with broccoli under three soil management practices: (i) soil mixed with municipal sewage sludge, (ii) soil mixed with yard waste compost, and (iii) no-mulch rototilled bare soil. The main objective of this investigation was to study the effect of mixing native soil with municipal sewage sludge or yard waste compost, having considerable amounts of organic matter, on off-site movement of dimethoate residues into runoff and infiltration water following spring rainfall. The initial deposits of dimethoate were 6.2 and 21.4 micro g g(-1) on broccoli heads and leaves, respectively. These residues dissipated rapidly and fell below the maximum residue limit of 2 micro g g(-1) on the heads and leaves after 10 and 14 d, respectively, with half-lives of 5.7 d on broccoli heads and 3.9 d on the leaves. Dimethoate residues detected in top 15 cm of soil (due to droplet drift and wash off residues from broccoli foliage) one day (d) following spraying, were 30.5 ng g(-1) dry soil in the sewage sludge treatment, and 46.1 and 134.5 ng g(-1) dry soil in the yard waste and no mulch treatments, respectively. Water infiltration was greater from yard waste compost treatment than from no mulch treatment, however concentrations of dimethoate in the vadose zone of the three soil treatments did not differ.     

Long-Term Community Dynamics of Small Landbirds with and Without Exposure to Extensive Disturbance from Military Training Activities

Military training activities are known to impact individual species, yet our understanding of how such activities influence animal communities is limited. In this study, we used long-term data in a case study approach to examine the extent to which the local small landbird community differed between a site in northeast Kansas that experienced intensive disturbance from military training activities (Ft. Riley Military Installation) and a similar, nearby site that experienced minimal human disturbance (Konza Prairie Biological Station). In addition, we characterized how the regional pool of potential colonizers influenced local community dynamics using Breeding Bird Survey data. From 1991 to 2001, most species of small terrestrial landbirds (73%) recorded during breeding surveys were found at both sites and the mean annual richness at Ft. Riley (39.0 ± 2.86 [SD]) was very similar to that of Konza Prairie (39.4 ± 2.01). Richness was maintained at relatively constant levels despite compositional changes because colonizations compensated local extinctions at both sites. These dynamics were driven primarily by woodland species that exhibited stochastic losses and gains and were present at a low local and regional abundance. Our results suggest that military training activities may mimic natural disturbances for some species in this area because the small landbird community did not differ markedly between sites with and sites without extensive human disturbance. Although our results suggest that military training is not associated with large changes in the avian community, additional studies are needed to determine if this pattern is found in other ecological communities.     

Quantifying progress toward a conservation assessment for all plants

The Global Strategy for Plant Conservation (GSPC) set an ambitious target to achieve a conservation assessment for all known plant species by 2020. We consolidated digitally available plant conservation assessments and reconciled their scientific names and assessment status to predefined standards to provide a quantitative measure of progress toward this target. The 241,919 plant conservation assessments generated represent 111,824 accepted land plant species (vascular plants and bryophytes, not algae). At least 73,081 and up to 90,321 species have been assessed at the global scale, representing 21–26% of known plant species. Of these plant species, at least 27,148 and up to 32,542 are threatened. Eighty plant families, including some of the largest, such as Asteraceae, Orchidaceae, and Rubiaceae, are underassessed and should be the focus of assessment effort if the GSPC target is to be met by 2020. Our data set is accessible online (ThreatSearch) and is a baseline that can be used to directly support other GSPC targets and plant conservation action. Although around one‐quarter of a million plant assessments have been compiled, the majority of plants are still unassessed. The challenge now is to build on this progress and redouble efforts to document conservation status of unassessed plants to better inform conservation decisions and conserve the most threatened species.     

A Canadian Federal Viewpoint on the Regulatory Process for Air Pollution Control

The following remarks are excerpted from an address presented by Mr. Rivers on October 7, 1980 to the 4th annual meeting of the Atlantic Canada Chapter of APCA's Northeast Atlantic International Section.     

Mobility of dimethoate residues from spring broccoli field

Dimethoate [O, O-dimethyl-S-(N-methylcarbamoyl-methyl) phosphorodithioate] is a broad-spectrum systemic insecticide currently used worldwide and on many vegetables in Kentucky. Dimethoate is a hydrophilic compound (log K_OW = 0.7) and has the potential of offsite movement from the application site into runoff and infiltration water. The dissipation patterns of dimethoate residues were studied on spring broccoli leaves and heads under field conditions. Following foliar application of Dimethoate 4E on broccoli foliage at the rate of 0.47 L acre^?1, dimethoate residues were monitored in soil, runoff water collected down the land slope, and in infiltration water collected from the vadose zone. The study was conducted on a Lowell silty loam soil (pH 6.9) planted with broccoli under three soil management practices: (i) soil mixed with municipal sewage sludge, (ii) soil mixed with yard waste compost, and (iii) no-mulch rototilled bare soil. The main objective of this investigation was to study the effect of mixing native soil with municipal sewage sludge or yard waste compost, having considerable amounts of organic matter, on off-site movement of dimethoate residues into runoff and infiltration water following spring rainfall. The initial deposits of dimethoate were 6.2 and 21.4 μ g g^?1 on broccoli heads and leaves, respectively. These residues dissipated rapidly and fell below the maximum residue limit of 2 μ g g^?1 on the heads and leaves after 10 and 14 d, respectively, with half-lives of 5.7 d on broccoli heads and 3.9 d on the leaves. Dimethoate residues detected in top 15 cm of soil (due to droplet drift and wash off residues from broccoli foliage) one day (d) following spraying, were 30.5 ng g^?1 dry soil in the sewage sludge treatment, and 46.1 and 134.5 ng g^?1 dry soil in the yard waste and no mulch treatments, respectively. Water infiltration was greater from yard waste compost treatment than from no mulch treatment, however concentrations of dimethoate in the vadose zone of the three soil treatments did not differ.     

Women and children last: An essay on sex discrimination in disasters

In general, little attention has been given to differential survival between the sexes in disasters. Consideration of physiological differences between males and females would suggest that, all things being equal, morbidity and mortality after disaster, particularly where food shortage is involved, should indicate an excess male mortality. Such statistics as exist in disasters, as in chronic underdevelopment, show that it is females and especially girl children who are at highest risk. The basis of this lies in sex discrimination which is implicit in most social systems.     

Growth,nutrient uptake capacities and tissue constituents of the macroalgae Cladophora vagabunda and Gracilaria tikvahiae related to site-specific nitrogen loading rates

Cladophora vagabunda (L.) van den Hoek and Gracilaria tikvahiae (McLachlan) have become dominant components of the macroalgal assemblage in Waquoit Bay, a Massachusetts embayment, possibly due to nitrogen (N) enrichment from anthropogenic inputs transported via groundwater. During 1989–1993, we measured site-related growth, ammonium uptake rates and tissue constituents of these macroalgae from areas subject to high N loading rates (Childs River) and lower N loadings rates (Sage Lot Pond). We also conducted in situ and microcosm enrichment experiments to determine what limited algal growth throughout the year. Our results indicated that these species are strongly affected by and have a strong impact on the N environment of this embayment. For example, C. vagabunda and G. tikvahiae from Childs River had higher light-harvesting pigments and tissue-N concentrations than Sage Lot Pond populations. Additionally, both Childs River populations showed greater site-specific growth and N uptake rates, particularly during the summer period of peak growth. In fact, maximum uptake rates of 90 and over 140 mol dry wt g^-1 h^-1 for Childs River C. vagabunda and G. tikvahiae, respectively, suggest that these species can remove substanital quantities of N from overlying waters, and may be responsible for low (often (<1 M) water-column nutrient concentrations during summer. In situ and tank enrichment experiments indicated that growth rates were limited by available N during summer, while P may be limiting during a brief period toward the end of the annual growth cycle (autumn). Under experimental enrichment, growth rates of Sage Lot Pond algae were similar to values measured at the site receiving higher N inputs, and generally, G. tikvahiae showed growth enhancement (up to 0.2 doublings d^-1) under light-saturating conditions (0.5 m) while C. vagabunda showed nutrient-enhanced growth at 2.5 m. The effects of available nutrients on algal growth were strongly influenced by irradiance and temperature, resulting in a complex seasonal interaction that emphasized the dynamic nature of species response to N loading. Dominance by these two macroalgae in Waquoit Bay, as in other areas undergoing eutrophication, is likely related to physiological strategies that enable these species to tolerate large environmental variations, to take advantage of greater N availability and to survive indirect effects of N loading (e.g. reduced irradiance, anoxia).     

Fragmentation effects on an endangered species across a gradient from the interior to edge of its range

Understanding how habitat fragmentation affects individual species is complicated by challenges associated with quantifying species-specific habitat and spatial variability in fragmentation effects within a species’ range. We aggregated a 29-year breeding survey data set for the endangered marbled murrelet (Brachyramphus marmoratus) from >42,000 forest sites throughout the Pacific Northwest (Oregon, Washington, and northern California) of the United States. We built a species distribution model (SDM) in which occupied sites were linked with Landsat imagery to quantify murrelet-specific habitat and then used occupancy models to test the hypotheses that fragmentation negatively affects murrelet breeding distribution and that these effects are amplified with distance from the marine foraging habitat toward the edge of the species’ nesting range. Murrelet habitat declined in the Pacific Northwest by 20% since 1988, whereas the proportion of habitat comprising edges increased by 17%, indicating increased fragmentation. Furthermore, fragmentation of murrelet habitat at landscape scales (within 2 km of survey stations) negatively affected occupancy of potential breeding sites, and these effects were amplified near the range edge. On the coast, the odds of occupancy decreased by 37% (95% confidence interval [CI] –54 to 12) for each 10% increase in edge habitat (i.e., fragmentation), but at the range edge (88 km inland) these odds decreased by 99% (95% CI 98 to 99). Conversely, odds of murrelet occupancy increased by 31% (95% CI 14 to 52) for each 10% increase in local edge habitat (within 100 m of survey stations). Avoidance of fragmentation at broad scales but use of locally fragmented habitat with reduced quality may help explain the lack of murrelet population recovery. Further, our results emphasize that fragmentation effects can be nuanced, scale dependent, and geographically variable. Awareness of these nuances is critical for developing landscape-level conservation strategies for species experiencing broad-scale habitat loss and fragmentation.