Bacteriological Quality of Runoff Water from Pastureland

Runoff from a cow-calf pasture in eastern Nebraska was monitored for total coliforms (TC), fecal coliforms (FC), and fecal streptococci (FS) during 1976, 1977, and 1978. Bacteriological counts in runoff from both grazed and ungrazed areas generally exceeded recommended water quality standards. The FC group was the best indicator group of the impact of grazing. Rainfall runoff from the grazed area contained 5 to 10 times more FC than runoff from the fenced, ungrazed area. There was little difference in TC counts between the two areas, but FS counts were higher in runoff from the ungrazed area and reflected the contributions from wildlife. Recommended bacteriological water quality standards, developed for point source inputs, may be inappropriate for characterizing nonpoint source pollution from pasture runoff. The FC/FS ratio in pasture runoff was useful in identifying the relative contributions of cattle and wildlife. Ratios below 0.05 were indicative of wildlife sources and ratios above 0.1 were characteristic of grazing cattle. Occasions when the FC/FS ratio of diluted cattle waste exceeded one resulted from differential aftergrowth and die-off between FC and FS. The FC/FS ratio and percentage of Streptococcus bovis in pasture runoff are useful indicators for evaluating the effectiveness of livestock management practices for minimizing bacterial contamination of surface water. The importance of choice of medium for the enumeration of FS in runoff derived from cattle wastes is discussed.     

Control of nematode parasites by grazing management—I. Decontamination of cattle pastures by grazing with sheep

Between December and June, six paddocks that had been contaminated naturally with infective larvae of nematode parasites of cattle, were each subjected to one of six grazing treatments. The effects of these treatments on the infectivity of the pastures were assessed by slaughter and total worm counts of calves which subsequently grazed the paddocks, and by counts of larvae on pasture samples. Grazing by sheep during autumn resulted in reduced populations of Ostertagia ostertagi and Trichostrongylus axei, both in calves and on the pasture for up to 12 months after treatment. Similar effects were noted on pasture grazed by cattle repeatedly dosed with anthelmintics, and on ungrazed pasture. There was little effect of any treatment on numbers of Cooperia oncophora. It was concluded that the level of autumn contamination was of importance in determining the numbers of O. ostertagi in the following spring and summer.     

Bacteriological quality assessment of fresh marketed lettuce and fennel.

One-hundred and twenty samples of lettuce and 89 samples of fennel purchased from five retail outlets in the city of Bari (Italy) from October 1973 through September 1975 were examined for viable aerobic bacteria (AB), total coliforms (TC), fecal coliforms (FC), fecal streptococci (FS), and salmonellae. Comparative tests indicated that the results of bacteriological analysis of wash water from either vegetable by a membrane filter technique compared favorably with those of conventional cultural examination of the vegetable tissue for the purpose of providing an indication of the bacteriological quality of the samples. Using the membrane filter technique, 2-year average counts of 6.59 X 10(7) for AB, 5.95 X 10(4) for TC, 6.13 X 10(3) for FC and 2.24 X 10(3) for FS/100 g (fresh weight) were obtained with lettuce; with fennel, the corresponding figures were 2.32 X 10(6) for AB, 7.82 X 10(4) for TC, 7.8 X 10(4) for FC, and 3.15 X 10(3) for FS. Indicator bacteria were present in all samples examined. In addition, 68.3% of the lettuce and 71.9% of the fennel samples yielded one or more of the following Salmonella serotypes: S. schottmuelleri, S. typhimurium, S. thompson, S. dublin, S. typhi, and S. anatum.     

Highly effective reduction of fecal indicator bacteria counts in an ecologically engineered municipal wastewater and acid mine drainage passive co-treatment system

Passive co-treatment of municipal wastewater and synthetic acid mine drainage in a laboratory-scale, four-stage continuous flow reactor system was examined for changes in fecal indicator bacteria (FIB) counts. Raw municipal wastewater (MWW) from the City of Norman, Oklahoma was mixed at a 2:1 ratio with high-strength synthetic acid mine drainage and introduced to the system. The MWW contained varying concentrations of total coliforms (TC), fecal coliforms (FC), Escherichia coli, and fecal streptococci (FS). Initial concentrations ranged from 6 to 13, 0.6 to 6, 3 to 5, and 0.1 to 0.7 million cfu/100 mL, for TC, FC, E. coli, and FS, respectively. During the 6.6-day system residence time, a 100% reduction of all FIB was observed. However, FIB exhibited evidence of sub-lethal injury with slower colony formation rates on standard growth media after 81 h of retention. Extending standard incubation periods resulted in higher concentrations of all FIB in each treatment stage, except the final stage where only E. coli and TC counts increased. Although this co-treatment regime reduced FIB concentrations more effectively than conventional active or passive MWW treatment systems, further work can be done to optimize the efficiency of treating these wastes simultaneously.     

Soil and plant water relations in a crested wheatgrass pasture: response to spring grazing by cattle

Summary Few field studies have attempted to relate effects of actual livestock grazing on soil and plant water status. The present study was initiated to determine the effects of periodic defoliations by cattle during spring on soil moisture and plant water status in a crested wheatgrass (Agropyron cristatum (L.) Gaertn. and A. desertorum (Fisch. ex Link) Schult.) pasture in central Utah. Soil moisture in the top 130 cm of the soil profile was depleted more rapidly in ungrazed plots than in grazed plots during spring and early summer. Soil moisture depletion was more rapid in grazed plots in one paddock after 1 July due to differential regrowth, but there was no difference in soil water depletion between plots in another paddock during the same period. This difference in soil water depletion between paddocks was related to a difference in date of grazing. Although more water had been extracted from the 60 cm to 130 cm depths in ungrazed plots by late September, cumulative soil moisture depletion over the entire 193 cm profile was similar in grazed and ungrazed plots. Prior to 1 July, grazing had no effect on predawn leaf water potentials as estimated by a pressure chamber technique; however, after 1 July, predawn leaf water potentials were lower for ungrazed plants. Midday leaf water potentials were lower for grazed plants before 1 July, but did not differ between grazed and ungrazed plants after 1 July. A 4- to 8-day difference in date of defoliation did not affect either predawn or midday leaf water potentials. The observed differences in water use patterns during spring and early-summer may be important in influencing growth and competitive interactions in crested wheatgrass communities that are subject to grazing by domestic livestock.     

Long-term variations in abundance and distribution of sewage pollution indicator and human pathogenic bacteria along the central west coast of India

Safe water quality criteria on the load and types of microbial populations are important for human use from fishery, tourism and navigational viewpoints. To understand the variations in sewage pollution indicator and certain human pathogenic bacteria, data collected from various locations along central west coast of India during 2002–2007 were analyzed. Water and sediment samples were examined for total viable counts (TVC), pollution indicator bacteria (total coliforms – TC, fecal coliforms – FC and Escherichia coli – EC) and potential pathogens (Vibrio cholerae – VC, Shigella – SH, and Salmonella spp. – SA). In both Mandovi and Zuari estuaries, where fishing and tourist-related activities are sizable and long-term data collection was regular, we observed high counts of TC, FC, VC, SH and SA in particular during monsoon due to increased land runoff. Further, the abundance of TC and FC has increased significantly over the years in the water column to much above either USEPA or India permissible limits. The concentrations of Vibrio cholerae, and Shigella correlated with those of coliforms. Pathogenic bacteria were detected even 20 km and/or 25 km offshore mainly due to dumping of raw or improperly treated sewage effluents either from land, fishing trawlers and/or ships in the anchorage. Higher concentrations of fecal coliforms and pathogenic bacteria in neretic waters signify threats to environmental and human health.     

Effects of stock grazing on the ground invertebrate fauna of woodland remnants

Habitat fragmentation can leave formerly widespread habitat types represented by only small habitat ‘islands’, and the conservation of these remnants is frequently compromised by ongoing disturbance. In northern Victoria, grazing of woodland remnants by sheep and cattle has profound effects on the vegetation structure of the woodland by removing understorey and ground vegetation. To investigate the effects of grazing pressure on remnant grey box Eucalyptus microcarpa woodland in northern Victoria, we surveyed the ground invertebrate fauna in ungrazed woodland remnants, grazed woodland remnants, and grazed pasture. The number of invertebrates caught increased from ungrazed woodland to grazed woodland to pasture, but this increase was due primarily to the most abundant orders (Hymenoptera, Coleoptera and Aranaea), and two abundant taxa characteristic of pasture (Orthoptera and Dermaptera). In contrast, most of the less abundant orders followed the opposite pattern, and were caught in higher numbers (and as a higher proportion of the total catch) in ungrazed woodland. Ungrazed woodland had a more diverse ground invertebrate fauna, most likely due to the greater diversity of food and habitat resources provided by the less disturbed vegetation. The differences in invertebrate communities corresponded to differences in vegetation and litter layers. The reduction in biodiversity of remnants due to grazing has implications for conservation management of remnant woodland in agricultural landscapes.     

森林放牧对东北虎豹国家公园东部有蹄类动物灌草层食物资源的影响

森林放牧是中国东北虎豹国家公园内影响最广泛且强度最大的人类干扰之一。研究放牧对有蹄类动物食物资源的影响,是估算当前状态下东北虎和东北豹主要猎物承载力的关键,可以为国家公园的管理提供有效的科学依据。本研究于2016年在中国东北虎豹国家公园东部的牧场和非牧场区域分层抽取50个林下样地设置围栏对照实验,于2017年生长季进行灌草层植被调查 (每个样地的围栏与对照各随机调查3个1m×1m的样方,共调查300个植物样方) ,并应用红外相机技术获取对照样地内有蹄类动物丰富度和活动情况,研究放牧对研究区灌草层植物及动物的影响。研究结果显示：在生长季内,森林放牧显著降低林下灌草层植物生物量 (减少约24%),牧场样地的嫩枝叶显著降低。除禾草外,牧场样地中其他类别植物的氮含量均显著高于非牧场样地 (平均超出非牧场样地25 %)。非牧场样地梅花鹿的相 对丰富度指数 (RAI) 显著高于牧场样地,而狍与野猪的相对丰富度指数 (RAI) 在这两类样地之间没有显著差别。研究结果表明,东北虎豹国家公园东部森林放牧,减少了有蹄类动物灌草层食物资源,降低了有蹄类动物的多度。建议停止森林放牧,恢复有蹄类动物栖息地。     

Diets of prairie dogs (Cynomys mexicanus) co-existing with cattle or goats

Diets of prairie dogs (Cynomys mexicanus) co-existing with goats or cattle were examined using microhistological fecal analysis in a 1-year study on a grassland of northern Mexico. Consumption of forbs was generally higher (33% versus 21% across all seasons; P< 0.05) in prairie dog diets co-existing with cattle compared to prairie dogs co-existing with goats. The diet of prairie dogs grazing with goats was based around grasses (79% of total forage ingested versus 68% for prairie dogs on the pasture grazed by cattle all seasons; P<0.05). In general, prairie dogs showed a higher preference for forbs in the pasture grazed by cattle than in the pasture grazed by goats. Data for dietary overlap (69% across all seasons) pointed to a moderate diet similarity between prairie dogs grazing with goats or cattle. Prairie dogs co-existing with goats had a higher (P<0.05) fecal N concentration in the fall than prairie dog co-occurring with cattle (2.4±0.1 versus 2.1±0.1). In spring and summer, prairie dogs in the pasture shared with goats had higher (P<0.05) fecal P concentrations than prairie dog co-existing with cattle (3.0±0.4 versus 2.5±0.2 and 1.6±0.1 versus 1.0±0.1, respectively). The results of this study indicate distinct differences in diets of prairie dogs co-existing with goats or cattle, although these foraging differences did not affect negatively the diet quality of prairie dogs (based on fecal N and P data) grazing with goats, despite the highly degraded range in this site. Prairie dogs showed a high feeding adaptability, which allowed them to meet their nutritional needs in a highly degraded site around the goat's pens in a settlement with communal grazing land.     

Changes in composition and structure of a tropical dry forest following intermittent cattle grazing

In northwestern Costa Rica, cattle are being used as a "management tool" to reduce the amount of combustible material, mainly dominated by Hyparrhenia rufa, an African grass. This project is being developed within Parque Nacional Palo Verde and Reserva Biológica Lomas Barbudal, both of which form part of the only remaining tropical dry forests in Mesoamerica. To determine the short-term effects of cattle grazing on the natural vegetation, we compared the floristic composition within Palo Verde in an area under intermittent cattle grazing with an area that has not been grazed. There were significantly fewer plant species in the area with intermittent cattle grazing compared to the area with no grazing. Floristic composition of these two habitats was different as reflected by both Fisher's alpha values and the Shannon index of diversity, both of which were significantly higher in the ungrazed site. The ungrazed area contained more plant species and was more similar to mature forest. The structure of the vegetation was significantly different between the intermittently grazed and ungrazed sites with more small stems (1-5 cm dbh) and fewer large stems (> 5 cm dbh) in the intermittently grazed habitat. These results indicate that cattle grazing has an impact on the dry forest by reducing the relative abundance and density of larger tree species and by changing the species composition and structure of the community. The current management plan implemented in Palo Verde and Lomas Barbudal is not appropriate because of the impact that cattle have on the structure of the natural vegetation and should not be considered a viable alternative in other protected areas of dry forest in the Neotropics. We suggest that alternative fire prevention measures be evaluated including hand-cutting H. rufa, the creation of more frequent and larger fire breaks, and the development of green breaks.     

Response to grazing after nine years of cattle exlusion in a Flooding Pampa grassland,Argentina

This paper reports on changes induced by the introduction of cattle in a grassland that had remained ungrazed for 9 yr, in comparison with two adjacent grasslands: one that remained enclosed and one that has been continuously subject to grazing. Basal cover was measured on 25 interception lines, each 1 m long, three times during one year. The variables studied were: total cover, cover of grasses and dicots, cover of creeping grasses, floristic composition, and dissimilarity among sites. At the first sampling, 2 yr after cattle re-introduction, the newly grazed site was more similar to the ungrazed than to the grazed site. The newly grazed site had very low cover of dicots; the species of dicots present were different from those found in the continuously grazed area. Creeping grasses had higher cover in the newly grazed site than in the other sites, and continued to increase. At the last sampling, one year later, the newly grazed site had become more similar to the contiuously grazed site. Only after 5 yr of cattle grazing the exotic dicots that were dominant in the continuously grazed site, were recorded in the re-opened site. The absence of propagules of these species or the absence of safe sites may account for this delayed invasion.     

Fecal indicator bacteria persistence under natural conditions in an ice-covered river.

Total coliform (TC), fecal coliform (FC), and fecal streptococcus (FS) survival characteristics, under natural conditions at 0 degrees C in an ice-covered river, were examined during February and March 1975. The membrane filter (MF) technique was used throughout the study, and the multiple-tube (MPN) method was used in parallel on three preselected days for comparative recovery of these bacteria. Survival was studied at seven sample stations downstream from all domestic pollution sources in a 317-km reach of the river having 7.1 days mean flow time (range of 6.0 to 9.1 days). The mean indicator bacteria densities decreased continuously at successive stations in this reach and, after adjustment for dilution, the most rapid die-off was found to occur during the first 1.9 days, followed by a slower decrease. After 7.1 days, the relative survival was TC less than FC less than FS, with 8.4%, 15.7%, and 32.8% of the initial populations remaining viable, respectively. These rates are higher than previously reported and suggest that the highest survival rates for these bacteria in receiving streams can be expected at 0 degree C under ice cover. Additionally, the FC-FS ratio was greater than 5 at all stations, indicating that this ratio may be useable for determining the source of fecal pollution in receiving streams for greater than 7 days flow time at low water temperatures. The MPN and MF methods gave comparable results for the TC and FS at all seven sample stations, with both the direct and verified MF counts within the 95% confidence limits of the respective MPNs in most samples, but generally lower than the MPN index. Although FC recovery on membrane filters was comparable results at stations near the pollution source. However, the results became more comparable with increasing flow time. The results of this study indicate that heat shock is a major factor in suppression of the FC counts on the membrane filters at 44.5 degree C. Heat shock may be minimized by extended incubation at 35 degrees C before exposure to the higher temperature.     

Mediating Water Temperature Increases Due to Livestock and Global Change in High Elevation Meadow Streams of the Golden Trout Wilderness

Rising temperatures due to climate change are pushing the thermal limits of many species, but how climate warming interacts with other anthropogenic disturbances such as land use remains poorly understood. To understand the interactive effects of climate warming and livestock grazing on water temperature in three high elevation meadow streams in the Golden Trout Wilderness, California, we measured riparian vegetation and monitored water temperature in three meadow streams between 2008 and 2013, including two “resting” meadows and one meadow that is partially grazed. All three meadows have been subject to grazing by cattle and sheep since the 1800s and their streams are home to the imperiled California golden trout (Oncorhynchus mykiss aguabonita). In 1991, a livestock exclosure was constructed in one of the meadows (Mulkey), leaving a portion of stream ungrazed to minimize the negative effects of cattle. In 2001, cattle were removed completely from two other meadows (Big Whitney and Ramshaw), which have been in a “resting” state since that time. Inside the livestock exclosure in Mulkey, we found that riverbank vegetation was both larger and denser than outside the exclosure where cattle were present, resulting in more shaded waters and cooler maximal temperatures inside the exclosure. In addition, between meadows comparisons showed that water temperatures were cooler in the ungrazed meadows compared to the grazed area in the partially grazed meadow. Finally, we found that predicted temperatures under different global warming scenarios were likely to be higher in presence of livestock grazing. Our results highlight that land use can interact with climate change to worsen the local thermal conditions for taxa on the edge and that protecting riparian vegetation is likely to increase the resiliency of these ecosystems to climate change.     

Utilisation of Wadden Sea salt marshes by geese in relation to livestock grazing

To arctic breeding geese, the salt marshes of the International Wadden Sea are important spring staging areas. Many of these marshes have always been grazed with livestock (mainly cattle and sheep). To evaluate the influence of livestock grazing on composition and structure of salt-marsh communities and its consequences for habitat use by geese, a total of 17 pairs of grazed and ungrazed marshes were visited both in April and May 1999, and the accumulated grazing pressure by geese was estimated using dropping counts. Observed grazing pressure was related to management status and to relevant vegetation parameters.The intensity of livestock grazing influences the vegetation on the marsh. Salt marshes that are not grazed by livestock are characterised by stands with a taller canopy, a lower cover of grasses preferred by geese, and a higher cover of plants that are not preferred.Overall goose-dropping densities are significantly lower in ungrazed marshes compared to marshes grazed by livestock. Some ungrazed marshes had comparatively high goose grazing pressure, and these were all natural marshes on a sandy soil, or artificial mainland marshes with a recent history of intensive livestock grazing. Goose grazing is associated with a short canopy. The plant communities with short canopy, dominated by Agrostis stolonifera, Festuca rubra and Puccinellia maritima, together account for 85% of all goose droppings in our data.The sites that were not visited by geese differed very little from those that were visited, in the parameters we measured. This might indicate that there was no shortage of available habitat for spring staging geese in the Wadden Sea, in the study period.     

Low vegetation recovery after short-term cattle exclusion on Robinson Crusoe Island

Livestock browsing and grazing are considered serious threats to the conservation of the Juan Fernández Islands’ flora, Chile. Nowadays the elimination of grazing by cattle is very difficult. In order to prevent the␣entrance of cattle into the native forests, an 8.3 km-long fence was established on the main island (Robinson Crusoe). The response of the vegetation was evaluated during 27 months of exclusion. The changes in abundances and composition of species were monitored in 12 permanent plots, each of 25 m², located in ungrazed and grazed areas. We expected an increase in plant height and total ground cover in the ungrazed area, and also a directional compositional change towards forest species. We found five different patterns of variation or non-variation for the 22 species observed: (i) one species (Acaena argentea) diminished in abundance in the ungrazed area; (ii) another one (Conium maculatum) increased in the ungrazed area; (iii) one species (Vulpia bromoides) increased in the grazing area; and some species displayed no net variation, but they showed (iv) a nearly constant occurrence, or (v) they appeared and disappeared sporadically. Contrary to our hypothesis, the vegetation showed no net differences in cover on both sides of the fence. As expected, plant height increased in the ungrazed area. In this area, we detected no noteworthy changes in floristic composition towards forest species. On the contrary, four new pastureland species appeared outside of the exclusion area during the last year of evaluation. Other ungrazed sectors of the island showed qualitative differences from grazed sectors, such as major height and density of plants, and lower intensity of browsing, grazing, and trampling, attributable to a reduction of herbivorous pressure. The modest responses reported in this study could be related to the short lapse of time since the exclusion, soil compaction, overgrowth by a single species (A. argentea), great seasonal variations in different species’ abundances, the reduction in the number of cattle grazing the area previous to the fence’s installation, and persistent herbivory by rabbits (Oryctolagus cuniculus L.). We conclude that the effect of grazing by cattle is␣less than expected, and that there are other factors that delay the recovery of the Juan Fernández pasturelands.     

Variations in Ixodes ricinus Density and Borrelia Infections Associated with Cattle Introduced into a Woodland in The Netherlands

The effect of introduced large herbivores on the abundance of Ixodes ricinus ticks and their Borrelia infections was studied in a natural woodland in The Netherlands. Oak and pine plots, either ungrazed or grazed by cattle, were selected. Ticks were collected weekly by blanket dragging. Borrelia infections were determined by PCR and restriction fragment length polymorphism. Rodent densities were estimated using mark-release-recapture methods. On occasion, the cattle were inspected for tick infestations. Meteorological data were recorded for each habitat. Significantly more ticks were collected in the ungrazed woodland than in the grazed woodland. The ungrazed oak habitat had higher tick densities than the pine habitat, while in the grazed habitats, tick densities were similar. Borrelia infection rates ranged from zero in larvae to 26% in nymphs to 33% in adult ticks, and B. afzelii, B. burgdorferi sensu stricto, B. garinii, and B. valaisiana were the species involved. Coinfections were found in five ticks. There was no effect of the presence of cattle on Borrelia infections in the ticks. In the ungrazed area, Borrelia infections in nymphs were significantly higher in the oak habitat than in the pine habitat. More mice were captured in the ungrazed area, and these had a significantly higher tick burden than mice from the grazed area. Tick burden on cattle was low. The results suggest that grazing has a negative effect on small rodents as well as on ticks but not on Borrelia infections. Implications of these results for management of woodland reserves and risk of Lyme disease are discussed.     

Identification of strains isolated as total and fecal coliforms and comparison of both groups as indicators of fecal pollution in tropical climates

This study was undertaken to better characterize the groups of total coliforms (TC) and fecal coliforms (FC) and to evaluate both groups as indicators of fecal contamination of drinking well water in a tropical climate (The Ivory Coast, West Africa). Isolated colonies obtained as TC or FC on membrane filters were identified using the API-20E system. From the well water samples, 58 golden-green colonies with a metallic sheen isolated on Endo medium (TC) were identified as Escherichia coli (55%), Enterobacter (26%), Klebsiella (14%), Proteus (3%), and Citrobacter (2%). Among 132 colonies isolated on Endo medium as non-TC (not showing the characteristic golden metallic sheen), 10% were identified as E. coli. The 196 blue colonies isolated on M-FC medium at 44.5 degrees C (FC) were identified as E. coli (66%), Klebsiella (12%), Enterobacter (10%), Citrobacter (5%), Salmonella (3%), Serratia (3%), Proteus (2%), and Yersinia (0.5%). Among 24 nonblue colonies on M-FC medium, none were identified as E. coli. Of the colonies isolated from human feces, E. coli represents 92% of the TC and 89% of the FC. Although these results are limited, they tend to confirm the greater specificity of the fecal coliform technique over that of total coliform for the detection of fecal contamination of untreated well water. From the results presented here and the observations of other workers, it is suggested that the use of FC instead of TC should be considered as the method of choice for determining drinking water pollution of untreated groundwater supplies.     

Rainfall-induced release of fecal coliforms and other manure constituents: comparison and modeling

Modeling release of fecal coliforms is an important component of fate and transport simulations related to environmental water quality. Manure constituents other than fecal coliforms may serve as natural tracers of fecal contamination provided that their release from manure to runoff is similar to the fecal coliform release. The objectives of this work were to compare release of fecal coliforms (FC), chloride (Cl-), organic carbon (OC), and water-soluble phosphorus (P) from dissolving manure and to assess the performance of three models in describing the observed release. Bovine manure was applied on 0.5- by 0.3-m bare and vegetated subplots with 20% slope on sandy loam and clay loam soils. Concentrations of Cl-, FC, OC, and P were measured in runoff collected from troughs at the edges of the subplots at 5-min intervals during 1-h rainfall simulations. The one-parametric exponential model and two-parametric Vadas-Kleinman-Sharpley model and Bradford-Schijven model were fitted to the data. The Bradford-Schijven model had uncorrelated parameters, one of which was linearly related to the irrigation rate, and another parameter reflected the presence or the absence of vegetation. Kinetics of the FC release from manure was similar to the release kinetics of P and OC. The Bradford-Schijven model is recommended to simulate the release of manure constituents.     

The impact of overgrazing on dung beetle diversity in the Italian Maritime Alps

Dung beetles (Coleoptera: Scarabaeidae) are undoubtedly the most typical and ecologically relevant insects of grazed alpine habitats because they provide valuable ecological services such as biological pest control and soil fertilization. Despite the great ecological contribution of these insects to pasture ecosystem functioning, little is known about their direct or indirect relationships with pastoral activities. The main aim of the study was to assess whether dung beetle diversity was influenced by different intensities of cattle grazing. Dung beetle communities of two adjacent alpine valleys within the Maritime Alps Natural Park (north-western Italian Alps), representing overgrazed and ungrazed pastures, were studied by pitfall trapping. A hierarchical design (three levels: valleys, transects, and replicates) was established for additive partitioning of γ-diversity and Indicator Species Analysis. Evenness and Shannon diversity were significantly higher at the ungrazed than at the overgrazed site because abundances were much more evenly distributed at the former than at the latter site (where one species was dominant over all the others). Dung beetle abundance and species richness of the overgrazed graminaceous pasture vegetation types were in most cases significantly lower than those of the ungrazed nongraminaceous vegetation type. In the additive partitioning of γ -diversity analysis relative to the whole study area, the randomization procedure indicated that the contribution of β to γ-diversity was significantly different from that expected by chance, suggesting that one or more environmental factors has intervened to change the partition of total diversity in the system considered. The analysis of the preferences and fidelity of species (Indicator Species Analysis) showed that only one species chose overgrazed pastures; all the others positively selected the ungrazed site, or the only ungrazed pasture vegetation type (Rumicetum alpini Beger) occurring at the overgrazed site. Results conformed to evidences that overgrazing represents a serious threat to the conservation of alpine dung beetles. To conserve local dung beetle assemblages, especially in protected areas, cattle overgrazing should be avoided. This does not mean, however, that pastoral activities are incompatible with biodiversity conservation. The contemporaneous presence of wild ungulates and low intensity extensive pastoral activities may be useful to preserve both local dung beetle assemblages and alpine pasture ecosystems.     

Faecal contamination of drinking water sources of Dhaka city during the 2004 flood in Bangladesh and use of disinfectants for water treatment

AIMS: To describe the extent of faecal pollution and point of use water treatment strategy during and after the 2004 flood in Dhaka. METHODS: A total of 300 water samples were collected from 20 different drinking water sources in Kamalapur, Dhaka city from August 2004 to January 2005. The level of faecal contamination was estimated using measurements of faecal indicator bacteria (total coliforms, faecal coliforms and faecal streptococci) and isolation of Vibrio cholerae was carried out following standard procedures. Total dissolved solids, dissolved oxygen, hardness, chloride and pH were also monitored. The efficacy of four disinfectants including Halotab, Zeoline-200, alum potash and bleaching powder were tested as point of use water treatment agents. The unacceptable level of contamination of total coliforms (TC), faecal coliforms (FC) and faecal streptococci (FS) ranged from 23.8% to 95.2%, 28.6% to 95.2% and 33.3% to 90.0%, respectively. The isolation rates of V. cholerae O1 and O139 were both 0.33%, and non-O1/non-O139 was 7.0%. CONCLUSION: Water collected during and after floods was contaminated with TC, FC, FS and V. cholerae. Although alum potash, bleaching powder, Halotab and Zeoline-200 were all effective general disinfectants, Halotab and Zeoline-200 were superior to bleaching powder and alum potash against FC. SIGNIFICANCE AND IMPACT OF THE STUDY: During and after floods, point of use water treatment could reduce waterborne diseases among flood-affected people.