Floristic composition and soil characteristics (moisture, pH, nutrient contents) in abandoned upland rice paddies of different ages were analyzed to clarify the regenerative aspects of succession as a tool for habitat restoration. The study sites represented five seral stages: newly abandoned paddy fields; successional paddy fields abandoned for 3, 7, and 10 years; and a 50‐year‐old Alnus japonica forest. A vegetation sere was apparent in changes of dominant plant species in the order Alopecurus aequalis var. amurensis (annual grass), Aneilema keisak (annual forb), Juncus effusus var. decipiens (rush), Salix koriyanagi (willow), and Alnus japonica (alder) communities. These temporal stages resemble the spatial zonation of vegetation in local riparian floodplain ecosystems, indicating a hydrosere, with soil moisture decreasing over time. Age distributions and life forms of the dominant plant species support a “tolerance” model of secondary succession, in which the established species persist into later successional stages. Persistence of earlier colonizers led to a net cumulative increase in species richness and a more even distribution of species cover with increasing field age. Between 10 and 50 years, vegetation stabilizes as an alder community. Soil moisture content decreased steadily with paddy field age after an initial rise immediately after their abandonment, whereas pools of organic matter, N, P, K, Ca, and Mg, increased with field age. The pace and direction of recovery of native vegetation and natural soil properties in these abandoned rice paddies resembled classic old field succession, a form of secondary succession that often serves as a template for guiding restoration efforts. Active intervention, in particular dismantling artificial levees, could accelerate the recovery process, but natural habitat recovery generally appears sufficiently robust to achieve “passive” restoration of this rare community without intervention.

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In the study, the effects of elevated CO 2 and temperature on the photosynthetic characteristics, chlorophyll content, nitrogen content, carbon content, and C/N ratio of Phytolacca insularis and Phytolacca americana were examined under control (ambient CO 2 + ambient temperature) and treatment (elevated CO 2 + elevated temperature) for 2 years (2008 and 2009). The photosynthetic rate, transpiration rate and water use efficiency of two plant species were higher under the treatment than the under the control. The stomatal conductance of P. insularis was higher under the control, but that of P. americana was not significantly affected by CO 2 and temperature under the treatment. The chlorophyll contents of two species were decreased about 72.5% and 20%, respectively, by elevated CO 2 and temperature. The nitrogen contents of two species were not significantly altered by increase in CO 2 and temperature. The carbon contents of the two species were higher under the treatment than under the control. The C/N ratio of P. insularis was higher under the treatment but that of P. americana was not significantly affected by CO 2 and temperature. These results demonstrated that the physiological responses of P. insularis native plants might be more sensitively influenced by a CO 2-mediated global warming situation than those of the P. americana invasive plants.

Abstract:The potential role of 80% methanolic extract of Boehmeria nivea (L.) Gaudich., Urticaceae, root in the treatment of diabetes, along with its antihyperlipidemic and antioxidant effects, was studied in streptozotocin-induced diabetic male Wistar rats. Preliminary screening of the extract revealed the presence of polyphenolics and fl avonoids. The animal study was conducted with variable doses of 125, 250 and 500 mg/ kg of extract for 21 days in diabetic rats. A signifi cant effect was observed at a dose of 500 mg/kg, which was comparable to the standard drug, glibenclamide. Administration of the extract at a 500 mg/kg dose resulted in a signifi cant reduction of fasting blood glucose, total cholesterol, triglycerides, blood urea, alanine aminotransferase, aspartate aminotransferase, urine sugar and urine ketone levels in diabetic rats in comparison with the diabetic control group. Additionally, this dose signifi cantly increased body weight, hemoglobin, plasma total protein, high density lipoprotein cholesterol, liver glycogen content, superoxide dismutase, reduced glutathione and catalase levels in diabetic rats at the end of 21 days of treatment. Therefore, dietary supplementation with Boehmeria nivea root extract could be benefi cial for correcting hyperglycemia, hyperlipidemia and enhancing the antioxidant defense system. Keywords