Under conditions of stress, shallow freshwater ecosystems can undergo a state change characterized by the rapid loss of macrophytes and subsequent dominance of phytoplankton. Elevated water temperature may promote such change. Here we report the impact of two warming regimes (continuous 3ЊC above ambient and 3ЊC above ambient during summer only), with two nutrient loadings and the presence or absence of fish, on 48 microcosm ecosystems created to mimic shallow pond environments. We found that warming did not significantly encourage phytoplankton blooms, even in combination with increased nutrients and fish. Instead, macrophyte communities remained dominant. Macrophyte-associated invertebrates (gastropods and ostracods) increased in numbers in the warmed microcosms, potentially helping to stabilize the macrophyte communities. Nevertheless, warming produced trends in water chemistry that could be problematic. It increased phosphorus concentrations, total alkalinity, and conductivity. It decreased pH and oxygen saturation and increased the frequency of severe deoxygenation. These trends were largely independent of the other experimental treatments and support the suggestion that moderate warming has the potential to exacerbate existing eutrophication problems.

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shEEP farmers are generally quick to consider helminth parasitism as the cause of diarrhoea and illthrift in their lambs, because they are aware that effective helminth control using anthelmintic drugs is difficult to achieve. There is a general awareness among sheep farmers of the production-limiting disease potential of helminth parasites, the inherent difficulties in using anthelmintic drugs to suppress pasture contamination with third-stage infective larvae (L3), and the high prevalence of anthelmintic-resistant helminths. helminth control in cattle, on the other hand, is generally perceived to be more straightforward, because certain parasites such as Fasciola hepatica, while important, are inherently less pathogenic; fewer nematode genera are considered to be pathogenic; there is a greater range of both conventional and persistent acting anthelmintic products, many of which are routinely conveniently administered as pour-ons (Barton and others 2006); and the prevalence of anthelmintic resistance is considered to be low, especially in the most pathogenic nematode species, Ostertagia ostertagi. Cattle farmers are therefore generally slower than their sheep farmer counterparts to investigate the possibility of helminth parasitism as a cause of diarrhoea and illthrift in animals that have been treated with anthelmintic drugs in accordance with a prescriptive herd health plan. This short communication describes production loss caused by helminth parasites in weaned beef calves, despite adherence to a prescriptive herd health plan.approximately 350 weaned, small, springborn suckled calves were purchased annually from the west coast of scotland during October and November and then introduced to an 18-to 24-monthold finishing system on an arable farm in East Lothian. a rational herd health plan was rigidly adhered to, involving pour-on treatment with 0.5 mg/kg doramectin (Dectomax Pour-On solution for Cattle 5 mg/ml; Pfizer) and oral treatment with 12 mg/kg triclabendazole (Fasinex 10 per cent; Novartis animal health) of every calf on arrival. The calves were then kept outdoors for five to eight weeks on fields that had been grazed by yearling cattle during the previous summer, before being housed in groups of approximately 50 during December and January, depending on the weather conditions. Yearling cattle were all treated with a depot injection of 1 mg/kg moxidectin (Cydectin 10 per cent La for Cattle; Fort Dodge animal health) at turnout during May.On December 9, a group of approximately 50 eight-month-old calves that had been housed on the previous day, five weeks after arrival on the farm, was examined. The average weight of the calves was approximately 150 kg, the group was uniformly dull and ill thriven, and most had diarrhoeic faeces (Fig 1). Contrary to expectations, there was no evidence of respiratory disease; rather, the clinical findings were consistent with helminth parasitism. serum samples were collected from five calves to determine the glutamate dehydrogenase (GLDh), albumin and globulin concentra...