Threshold Dynamics of Vegetation and Their Management Implications in a Mongolian Shrubland

The concept of ecological threshold has spurred important advances in understanding the nonlinear behavior of ecosystems to various disturbances (Groffman et al. 2006, Suding and Hobbs 2009). Studies on lakes, coral reefs, and arid grasslands have shown that structural attributes of ecosystems can change abruptly along a disturbance gradient (Scheffer and Carpenter 2003, Mumby et al. 2007, Sasaki et al. 2008). Yet, such nonlinear response patterns are implicitly assumed to reflect the modification of system feedbacks and interactions. We know little about mechanistic linkages between nonlinear response patterns and underlying feedback mechanisms, and the irreversibility of nonlinear responses. Consequently, in many applied settings, the threshold concept is being adopted without sufficient evaluation of evidence. Here, we present initial work towards the understanding of threshold dynamics of vegetation in a Mongolian shrubland. Our study should enhance the conceptual development of ecological threshold as well as human decision-making

Living alone is associated with depression among the elderly in a rural community in Japanp syg_402 179..185

Abstract Aim: This study aimed to investigate factors associated with depression in a sample of elderly Japanese individuals in a rural community and to examine differences among factors associated with individuals living alone or living with others. Methods: Using a population-based sample from rural Japan, we assessed a total of 1552 participants aged 65 years or older by mailing a survey and evaluating responses based on the Geriatric Depression Scale. Factors associated with depression were also examined. Results: We received 964 valid responses. Depressed subjects comprised 20.5% of the sample. Living alone was significantly related to depression. In individuals living alone, depression was associated with loss of appetite, suicidal ideation, financial strain, and worries in life. However, multiple linear regression analyses revealed that the influence of living alone was negated by having a good social support system. Conclusion: These findings confirm that living alone is an important factor in depression among the elderly in a rural part of Japan. Results also confirm what others have found in Western cultures: high levels of social support, awareness of receiving social support, and willingness to receive assistance may reduce the risk of depression

GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands

GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (releves) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001;... 1,000 m(2)) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database " sPlot". Its main aim is to facilitate studies on the scale-and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board

Effects of sedge and cottongrass tussocks on plant establishment patterns in a post-mined peatland, northern Japan

Facilitation (positive inter-specific interaction) plays an important role in promoting succession in harsh environments. To examine whether tussocks facilitate the establishment of other species, after peat mining, investigations were carried out in a formerly Sphagnum-dominated wetland (Sarobetsu mire, northern Japan). Two tussock-forming species, Carex middendorffii and Eriophorum vaginatum, have established in sparsely vegetated areas, with a dry ground surface, since peat extraction ended. The following factors were examined, in three microhabitats created by tussocks (center = raised tussock center, edge = tussock edge covered with litter, and flat = flat areas without tussocks): (1) relationships between tussock microhabitats and plant distributions, and (2) the effects of tussocks on survival, growth, flowering and seed immigration of common species. Two (1 × 10 m) plots were established, in each of three sparsely vegetated sites, in September 2005. Tussocks were mapped in each plot, and species, location, flowering, growth stage (seedling, juvenile and fertile) and size of all plants were recorded, during snow-free periods from September 2005 to September 2006. Seed traps were used to investigate seed dispersal from June to October 2006. Four native species, Drosera rotundifolia, Lobelia sessilifolia, Moliniopsis japonica, Solidago virgaurea, and an exotic species, Hypochaeris radicata, were most common. During seedling and juvenile stages, these species were distributed more densely at the tussock edge than in the flat areas, but were less common at the center. H. radicata had a higher survival rate at the edge than in the flat during the winter. The annual growth of H. radicata, L. sessilifolia and S. virgaurea was higher at the edge. Seed traps detected that D. rotundifolia seeds accumulate more at the edge. In conclusion, tussocks facilitated plant establishment in the edge microhabitat by providing litter cover, enhancing seed accumulation, germination and survival, and thus promoted revegetation. However, Sphagnum mosses have not established in the study sites, and the vegetation differs strongly from the areas where no peat mining had taken place

Relationships between the developments of seedbank, standing vegetation and litter in a post-mined peatland

To clarify seedbank developmental pattern and its determinants, we examined relationships between seedbank, standing vegetation, and litter in a post-mined peatland on Sarobetsu Mire, northern Japan. In late fall 2006 and early summer 2007, peat was sampled from four vegetation types, and litter was also sampled from two of the four vegetation where thick litter was accumulated. Seed germination tests were performed by the samples in a glasshouse. The results were compared to the standing vegetation and litter accumulation. Seed density and species richness in seedbank gradually increased with increasing vegetation cover. Seeds in surface layer germinated more in fall than in summer. In vegetation with thick litter, small seeds, such as Drosera rotundifolia and Gentiana triflora, germinated more from peat than from litter in summer, probably due to the downward movement. Seed density in litter decreased from fall to the next summer. Moliniopsis japonica and Rhynchospora alba developed short-term persistent seedbank, whereas D. rotundifolia and G. triflora preserved long-term persistent seedbank in peat covered with thick litter. Seedbank development follows the development of the standing vegetation with litter. Litter derived from the standing vegetation is a prime determinant on the seedbank composition and development, by acting as seed trap and keeping seed dormancy

Temporal trends in the accumulation of alien vascular plant species through intentional and unintentional introductions in Japan

Clarifying the temporal trends of alien plant accumulation is increasingly important for informing global and national management efforts to decelerate biological invasions, following the adoption of Target 6 of the Kunming-Montreal Global Biodiversity Framework. However, such trends have not yet been analysed in many countries including Japan, which has the highest number of naturalised alien plant species among islands. To clarify the past and recent trends in the accumulation of alien plant species in Japan, we compiled a dataset of the year of first record for 1,463 alien vascular plant species deliberately and accidentally introduced and analysed the changes in the annual number of first records over time for each overall, intentional and unintentional introductions. We found that, overall, the annual number of first records of alien plant species in Japan began to increase in the late 1800s, and the increase continued until the late 1950s, with an estimated maximum of 15.7 new species per year. The increase then halted by 1960 and began a slow decline; the estimated average records per year between 1991 and 2000 dropped to 13.3 species. Since 1900, the annual number of first records associated with intentional introductions has more than doubled the number linked to unintentional introductions. Additionally, the proportion of invasive species brought through intentional introductions was larger than that brought through unintentional introductions. We highlight that while Japan experienced a rapid accumulation of alien plant species, including invasive species, by the 1950s, the rate of accumulation showed signs of saturation by 1960 and has since been slowly declining. Further deceleration and prevention of the introduction of invasive alien species, as targeted in the Kunming-Montreal Global Biodiversity Framework, may be achieved through increased investment in pathway management, especially management of intentional pathways

Zonisamide attenuates α-synuclein neurotoxicity by an aggregation-independent mechanism in a rat model of familial Parkinson's disease.

The anti-epileptic agent zonisamide (ZNS) has been shown to exert protective effects in neurotoxin-based mouse models of Parkinson disease. However, it is unknown whether ZNS can attenuate toxicity of familial Parkinson's disease-causing gene products. In this study, we investigated the effects of ZNS on neurodegeneration induced by expression of A53T α-synuclein in the rat substantia nigra using a recombinant adeno-associated virus vector. Expression of A53T α-synuclein yielded severe loss of nigral dopamine neurons and striatal dopamine nerve terminals from 2 weeks to 4 weeks after viral injection. Oral administration of ZNS (40 mg/kg/day) significantly delayed the pace of degeneration at 4 weeks after viral injection as compared with the vehicle group. This effect lasted until 8 weeks after viral injection, the final point of observation. ZNS treatment had no impact on the survival of nigrostriatal dopamine neurons in rats expressing green fluorescent protein. Quantification of striatal Ser129-phosphorylated α-synuclein-positive aggregates showed that these aggregates rapidly formed from 2 weeks to 4 weeks after viral injection. This increase was closely correlated with loss of nigrostriatal dopamine neurons. However, ZNS treatment failed to alter the number of all striatal Ser129-phosphorylated α-synuclein-positive aggregates, including small dot-like and large round structures. The number of these aggregates was almost constant at 4 weeks and 8 weeks after viral injection, although ZNS persistently prevented loss of nigrostriatal dopamine neurons during this period. Also, ZNS treatment did not affect the number of striatal aggregates larger than 10 µm in diameter. These data show that ZNS attenuates α-synuclein-induced toxicity in a manner that is independent of the formation and maturation of α-synuclein aggregates in an in vivo model of familial Parkinson's disease, suggesting that ZNS may protect nigrostriatal dopamine neurons by modulating cellular damage or a cell death pathway commonly caused by neurotoxins and α-synuclein