The influence of partial timber harvesting in riparian buffers on macroinvertebrate and fish communities in small streams in Minnesota,USA

Relatively few evaluations of aquatic macroinvertebrate and fish communities have been published in peer-reviewed literature detailing the effect of varying residual basal area (RBA) after timber harvesting in riparian buffers. Our analysis investigated the effects of partial harvesting within riparian buffers on aquatic macroinvertebrate and fish communities in small streams from two experiments in northern Minnesota northern hardwood-aspen forests. Each experiment evaluated partial harvesting within riparian buffers. In both experiments, benthic macroinvertebrates and fish were collected 1 year prior to harvest and in each of 3 years after harvest. We observed interannual variation for the macroinvertebrate abundance, diversity and taxon richness in the single-basin study and abundance and diversity in the multiple-basin study, but few effects related to harvest treatments in either study. However, interannual variation was not evident in the fish communities and we detected no significant changes in the stream fish communities associated with partially harvested riparian buffers in either study. This would suggest that timber harvesting in riparian management zones along reaches ≤200 m in length on both sides of the stream that retains RBA ≥ 12.4 ± 1.3 m² ha⁻¹ or on a single side of the stream that retains RBA ≥ 8.7 ± 1.6 m² ha⁻¹ may be adequate to protect macroinvertebrate and fish communities in our Minnesota study systems given these specific timber harvesting techniques.     

Effectiveness of five small Philippines’ coral reef reserves for fish populations depends on site-specific factors, particularly enforcement history

Community-managed, no-take marine reserves are increasingly promoted as a simple, precautionary measure to conserve biodiversity and sustain coral reef fisheries. However, we need to demonstrate the effects of such reserves to those affected by the loss of potential fishing grounds and the wider scientific community. We surveyed changes in fish communities in five small marine reserves in the central Philippines and three distant Control sites over seven years. We conducted underwater visual censuses of 53 fish families within the reserve (Inside), with a kilometre of the boundary (Outside) and at Control sites. We found significant differences between fish communities Inside and Outside the reserve only at the two sites with strictest compliance with fishing prohibition, while there were significant differences to distant Control sites in all cases. The strongest responses to reserve protection were found in predatory fishes (groupers and breams) and in butterflyfish. Other abundant fish families showed weak effects of protection. For all taxa analysed, we found significant effects of reserve Site and Site × Treatment interactions. The detection of fish responses to reserves is complicated by potential spillover effects, site-specific factors, particularly compliance, and the difficulty of identifying appropriate control areas.     

Treatment of canine dirofilariasis: pulmonary thromboembolism caused by thiacetarsamide--microscopic changes

Light and scanning electron microscopies were used to study the pulmonary embolism occurring in Dirofilaria immitis-infected dogs after treatment with thiacetarsamide. Lesions in control dogs (nontreated) which had been infected for 4 weeks with 9 Dirofilaria immitis adults were compared with lesions occurring in infected dogs at 2 weeks and at 4 weeks after they were treated with the adulticide. Extensive thromboembolism occurred in the caudal lobar pulmonary arteries of dogs at posttreatment weeks 2 and 4. Complicated villous proliferations were present at posttreatment week 2. The characteristic myointimal proliferation of dirofilariasis showed resolution in the large pulmonary arteries of the dogs at week 4. However, the caudal lobar pulmonary arterial and lung lesions were more severe in the later group. The pathophysiology of adulticide-induced thromboembolism and associated lung parenchymal changes were discussed.     

Comparison of endoscopic and full-thickness biopsy specimens for diagnosis of inflammatory bowel disease and alimentary tract lymphoma in cats

OBJECTIVE: To evaluate the accuracy of endoscopic biopsy (EB) specimens for diagnosis of alimentary tract lymphosarcoma in cats. DESIGN: Prospective study. ANIMALS: 22 cats with inflammatory bowel disease (IBD) or alimentary tract lymphosarcoma. PROCEDURES: Endoscopic biopsy specimens were obtained during endoscopy of the stomach and duodenum immediately prior to laparotomy or laparoscopic surgery, during which full-thickness biopsy (FTB) specimens were obtained. Accuracy of histopathologic diagnoses was compared between EB and FTB specimens. RESULTS: Lymphosarcoma was diagnosed in 10 cats on the basis of FTB specimens. Lymphosarcoma was detected in the jejunum and ileum in all 10 cats, in the duodenum in 9 cats, and in the stomach in 4 cats. In the same 10 cats, EB findings indicated a diagnosis of lymphosarcoma in 3 cats and were suggestive but inconclusive for lymphosarcoma in 3 cats. Lymphosarcoma was correctly diagnosed via gastric EB specimens in 3 of the 4 cats with gastric lymphosarcoma but evaluation of EB specimens led to an incorrect diagnosis of IBD in 4 cats with small intestinal lymphosarcoma. CONCLUSIONS AND CLINICAL RELEVANCE: EB specimens were useful for diagnosis of gastric lymphosarcoma but were not adequate for differentiating between IBD and lymphosarcoma in the small intestine. Because the most common sites of alimentary tract lymphosarcoma in cats are the jejunum and ileum, FTB specimens of those sites should be obtained via laparotomy or laparoscopy for accurate diagnosis. Laparoscopy may be a minimally invasive alternative to endoscopy and laparotomy for obtaining diagnostic biopsy specimens.     

Evaluation of 5 serologic assays to detect Rhodococcus equi pneumonia in foals

OBJECTIVE: To determine the sensitivity and specificity of 5 serologic assays used to diagnose Rhodococcus equi pneumonia in foals and to determine whether any of the assays could be used to identify affected foals prior to the onset of clinical signs or to differentiate between affected and unaffected foals when clinical signs first become apparent. DESIGN: Nested case-control study. ANIMALS: 26 foals. PROCEDURE: Serum samples were obtained from all foals at 2, 4, and 6 or 7 weeks of age. Additional samples were obtained from affected foals at the time of diagnosis of R equi pneumonia and from age-matched unaffected foals. Samples were tested with 3 ELISA, an agar gel immunodiffusion assay, and a synergistic hemolysis inhibition assay. RESULTS: Sensitivity and specificity data indicated that none of the assays could be used to reliably differentiate affected from unaffected foals at any testing period. Proportions of foals that had an increase in test values between paired samples collected at 4 and 6 or 7 weeks of age were not significantly different between affected and unaffected foals. For all assays, result values increased significantly over time; however, the rate of increase was not significantly different between affected and unaffected foals. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that serologic assays, whether performed on single or paired samples, cannot be used to reliably establish, confirm, or exclude a diagnosis of R equi pneumonia in foals.     

The effectiveness of eleven sterol biosynthesis-inhibiting fungicides against the take-all fungus,Gaeumannomyces graminis var. tritici,in relation to their physical properties

Eleven sterol biosynthesis-inhibiting fungicides were compared in experiments to determine the physico-chemical properties required for most effective control of take-all by soil treatment. All were active in agar culture against an isolate of the pathogen which causes take-all, Gaeumannomyces grammis var. tritici, with prochloraz being the most toxic (EC₅₀ 0.02 μg ml^?1) and PP 969 the least (EC₅₀ 0.44 μg ml^?1). Penconazole and PP 969 had vapour activity against the fungus in further bioassays on agar. In soil in pots, the most strongly lipophilic compound, buthiobate, was ineffective against take-all in wheat; triadimenol was most effective and, like flutriafol, nuarimol and PP 969, retained some effectiveness after 12 weeks in soil. PP 969, unlike penconazole or nuarimol, was effective in soil treated unevenly by mixing the fungicides in layers. PP 969 is relatively polar, and it is suggested that this property, allowing redistribution in soil water rather than as vapour, outweighed its poor intrinsic toxicity. The ideal soil-treatment fungicide should therefore be polar and also have good intrinsic activity and moderate persistence. None of the compounds tested had all these properties.     

The effect of piperonyl butoxide and triorthocresyl phosphate on the activity and metabolism of altosid (isopropyl 11-methoxy, 3,7,11-trimethyldodeca-2,4-dienoate) in Tenebrio molitor L. and Oncopeltus fasciatus (dallas)

Altosid (I) was found to have an ED₅₀ of 0.026 μg/g in T. molitor and 5.0 μg/g in O. fasciatus. The juvenilizing activity of I in T. molitor was increased by co-treatment with piperonyl butoxide (PB) and triorthocresyl phosphate (TOCP). The activity of I in O. fasciatus, was considerably decreased by PB and TOCP indicating the blocking of an activation reaction. The presumptive metabolities of I, isopropyl 11-hydroxy-3,7,11-trimethyldodeca-2,4-dienoate, (II), 11-methoxy-3,7,11-trimethyldodeca-2,4-dienoic acid (III), and 11-hydroxy-3,7,11-trimethyldodeca-2,4-dienoic acid (IV) were tested for juvenilizing activity in O. fasciatus and II was found to be four times more active than I. IV was more active than III but less active than I. Co-treatment of II with PB or TOCP did not decrease activity, indicating that II is a true activation product. Uptake studies with ¹⁴C-I showed that the difference in activity between the two insects was not due to differences in uptake. Forty-eight hours after treatment 30% of I was lost from the cuticle by evaporation. Metabolic studies showed that PB inhibited the formation of II and TOCP inhibited the formation of III in T. molitor while in O. fasciatus both synergists inhibited the formation of II.     

Environmental Concerns of Phosphorus Management in Potato Production

Phosphorus (P) losses from agricultural systems are a cause of degraded surface water quality of lakes and streams. In freshwater systems, P is often the most limiting nutrient for algae growth and an increase in P additions to these systems can cause a shift in ecology. These shifts can result in a degradation of the water resource as habitat or for recreation. In an effort to combat the negative effects of agriculture management practices on surface water quality, federal and state regulations require some level of assessment to guide P applications. Areas with large amounts of potato production are of particular concern with respect to P loss since potatoes are a high P demanding crop and are inefficient users of applied P. In many cases, soils in potato production are managed with a higher soil test P concentration compared to other crops and P applications for optimum production exceed P removal. When potato production fields are maintained at high soil test P levels, this may increase the risk of P loss in runoff. However, based on soils and landscape positions where potatoes are grown, there may be little risk of transport. While there appears to be little risk of P loss on low-sloping, sandy soils, output from the Wisconsin Phosphorus Index suggests that more steeply sloping fields can pose some risk, especially when soil test P concentrations exist at above optimum levels. At high soil test P levels, no P may be required for optimum yield in rotated crops, but production practices of these crops may need to be altered to reduce P losses. Furrow-irrigated and tile-drained fields may also pose risks of P loss to the environment. While the P demands of potato are greater than those for most crops, it is likely that most of this P will not be exported via surface runoff. Careful management considerations must be made when producing potatoes on high sloping soils, especially those close to surface water bodies. Future considerations of P management and water quality will focus on assessing leaching risk of P and this contribution to surface waters.     

Strong impacts of belowground tree inputs on soil nematode trophic composition

Trees have a key role in determining the composition of soil biota via both above and belowground resource-based mechanisms, and by altering abiotic conditions. We conducted an outdoor mesocosm experiment to investigate the relative impact of above and belowground tree inputs on soil nematode trophic composition, and examine whether tree-driven impacts differed between contrasting species (birch and pine). For both species, we created a factorial design of litter addition and root presence treatments. The litter addition treatment was equivalent to natural levels of litterfall; tree saplings were planted in mesocosms for the root presence treatment and an unplanted control treatment was established that had no litter or root inputs. Litter addition had a limited impact on soil nematode community composition: it primarily decreased omnivore and predatory nematode abundance in birch but had few other effects on the nematode community. By contrast, root presence markedly altered nematode community composition through changes in a range of trophic groups. For both birch and pine, there were significant increases in total, fungivore and predatory nematode abundance in root presence treatments, and furthermore, total and fungivore abundances were positively related to root biomass. Root presence of these contrasting tree species also had a distinctive impact on some specific nematode trophic groups; pine roots promoted bacterivore abundance while birch roots promoted root-hair feeding nematode abundance. These findings suggest strong bottom-up effects of belowground tree inputs, and indicate that particular components of the nematode community may be affected differently by resource quantity and quality. Consequently, we suggest that, in the short-term, belowground rather than aboveground tree inputs have a strong impact on soil food web structure and complexity.     

Treatment of Domestic Wastewater by Three Plant Species in Constructed Wetlands

Three common Appalachian plant species (Juncus effusus L., Scirpus validus L., and Typha latifolia L.) were planted into small-scale constructed wetlands receivingprimary treated wastewater. The experimental design includedtwo wetland gravel depths (45 and 60 cm) and five plantingtreatments (each species in monoculture, an equal mixture of the three species, and controls without vegetation), with two replicates per depth × planting combination. Inflow rates (19 L day^-1) and frequency (3 times day^-1) were designed to simulate full-scale constructed wetlands as currently used for domestic wastewater treatmentin West Virginia. Influent wastewater and the effluent from each wetland were sampled monthly for ten physical, chemical and biological parameters, and plant demographic measurements were made. After passing through these trough wetlands, the average of all treatments showed a 70% reduction in total suspended solids (TSS) and biochemical oxygen demand (BOD), 50 to 60% reduction in nitrogen (TKN), ammonia and phosphate, anda reduction of fecal coliforms by three orders of magnitude. Depth of gravel (45 or 60 cm) had little effect on wetland treatment ability, but did influence Typha and Scirpus growth patterns. Gravel alone provided significant wastewater treatment, but vegetation further improved many treatment efficiencies. Typha significantly out-performedJuncus and Scirpus both in growth and in effluent quality improvement. There was also some evidence that the species mixture out-performed species monocultures.Typhawas the superior competitor in mixtures, but a decline in Typha growth with distance from the influent pipe suggested that nutrients became limiting or toxicities may have developed.