湖北神农架自然遗产地社区参与现状及对策

社区参与意愿以及如何参与,直接影响到自然遗产的保护和开发活动。本文采用分层随机抽样和入户调查的方式,对湖北神农架自然遗产地社区居民的认知程度、参与现状和意愿诉求等3个方面开展了调查和研究。调查发现,受访者对自然遗产保护与开发有较高的认知度,目前社区整体参与程度较高;列入世界遗产后,社区居民在决策管理、商业经营、利益分配、社会保障等方面的意愿和诉求不会产生显著变化。建议从改变居民生活方式、转变社区就业方式、加强宣传教育、完善社区共管机制等方面进一步完善神农架自然遗产地社区的管理和建设。

Species spatial distributions in a warm-temperate deciduous broad-leaved forest in China

Spatial distribution is fundamental for understanding species coexistence mechanisms in forest communities.Here we comprehensively explored fine-scale spatial patterns of tree species in a secondary warm-temperate deciduous broad-leaved forest community in north China.Aggregated distribution patterns were predominant.Species functional traits had no significant effects on their spatial patterns.The aggregation intensity decreased with increasing DBH and abundance.The multivariate linear stepwise regression showed that abundance and maximum DBH were correlated with the aggregation intensity.Our results partially confirm that species attributes(abundance,DBH)and habitat heterogeneity may primarily contribute to spatial patterns and species coexistence in this secondary forest.

C:N:P stoichiometry of Ericaceae species in shrubland biomes across Southern China:influences of climate,soil and species identity

Aims Carbon(C),nitrogen(N)and phosphorus(P)stoichiometry strongly affect functions and nutrient cycling within ecosystems.However,the related researches in shrubs were very limited.In this study,we aimed to inves-tigate leaf stoichiometry and its driving factors in shrubs,and whether stoichiometry significantly differs among closely related species.Methods We analyzed leaf C,N and P concentrations and their ratios in 32 species of Ericaceae from 161 sites across southern China.We examined the relationships of leaf stoichiometry with environmen-tal variables using linear regressions,and quantified the interactive and independent effects of climate,soil and species on foliar stoi-chiometry using general linear models(GLM).Important Findings The foliar C,N and P contents of Ericaceae were 484.66,14.44 and 1.06 mg g−1,respectively.Leaf C,N and P concentrations and their ratios in Ericaceae were significantly related with latitude and altitude,except the N:P insignificantly correlated with latitude.Climate(mean annual temperature and precipitation)and soil properties(soil C,N and P and bulk density)were significantly influenced element stoichiom-etry.The GLM analysis showed that soil exerted a greater direct effect on leaf stoichiometry than climate did,and climate affected leaf traits mainly via indirect ways.Further,soil properties had stronger influ-ences on leaf P than on leaf C and N.Among all independent factors examined,we found species accounted for the largest proportion of the variation in foliar stoichiometry.These results suggest that species can largely influence foliar stoichiometry,even at a lower taxonomic level.

Differential Responses of the Activities of Antioxidant Enzymes to Thermal Stresses between Two Invasive Eupatorium Species in China

The effect of thermal stress on the antioxidant system was investigated in two invasive plants, Eupatorium adenophorum Spreng. and E. odoratum L. The former is sensitive to high temperature, whereas the latter is sensitive to low temperature. Our aim was to explore the relationship between the response of antioxidant enzymes and temperature in the two invasive weeds with different distribution patterns in China. Plants were transferred from glasshouse to growth chambers at a constant 25 ℃for I week to acclimatize to the environment. For the heat treatments, temperature was increased stepwise to 30, 35, 38 and finally to 42 ℃. For the cold treatments, temperature was decreased stepwise to 20, 15, 10 and finally to 5 ℃. Plants were kept in the growth chambers for 24 h at each temperature step. In E. adenophorum, the coordinated increase of the activities of antioxidant enzymes was effective in protecting the plant from the accumulation of active oxygen species （AOS） at low temperature, but the activities of catalase （CAT）, guaiacol peroxidase （POD）, ascorbate peroxidase （APX）, glutathione reductase （GR）, and monodehydroascorbate reductase （MDAR） were not accompanied by the increase of superoxide dismutase （SOD） during the heat treatments. As a result, the level of lipid peroxidation in E. adenophorum was higher under heat stress than under cold stress. In E. odoratum, however, the lesser degree of membrane damage, as indicated by low monodehydroascorbate content, and the coordinated increase of the oxygen. Datoxifying enzymes were observed in heat-treated plants, but the antioxidant enzymes were unable to operate in cold stress. This indicates that the plants have a higher capacity for scavenging oxygen radicals in heat stress than in cold stress. The different responses of antioxidant enzymes may be one of the possible mechanisms of the differences in temperature sensitivities of the two plant species.

Activity of Stress-related Antioxidative Enzymes in the Invasive Plant Crofton Weed(Eupatorium adenophorum)

Crofton weed is an invasive weed in southwestern China. The activities of several antioxidative enzymes involved in plant protection against oxidative stress were assayed to determine physiological aspects of the crofton weed that might render the plant vulnerable to environmental stress. Stresses imposed on crofton weed were heat （progressively increasing temperatures： 25 ℃, 30 ℃, 35 ℃, 38℃ and 42 ℃ at 24 h intervals）, cold （progressively decreasing temperatures： 25 ℃, 20 ℃, 15℃, 10 ℃ and 5℃ at 24h intervals）, and drought （without watering up to 4days）. The three stresses induced oxidative damage as evidenced by an increase in lipid peroxidation. The effect varied with the stress imposed and the length of exposure. The activity of superoxide dismutase （SOD） increased in response to all stresses but was not significantly different from the controls （P 〈 0.05） when exposed to cold stress. Catalase （CAT） activity decreased in response to heat and drought stress but increased when exposed to cold conditions. Guaiacol peroxidase （POD） and glutathione reductase （GR） activities increased in response to cold and drought but decreased in response to heat stress. The activity of ascorbata peroxidase （APX） responded differently to all three stresses. Monodehydroascorbate reductase （MDHAR） activity decreased in response to heat and drought, and slightly increased in response to the cold stress but was not significantly different from the controls （P 〈 0.05）. The activity of dehydroascorbata reductase （DHAR） increased in response to all three stresses. Taken together, the co-ordinate increase of the oxygen-detoxifying enzymes might be more effective to protect crofton weed from the accumulation of oxygen radicals at low temperatures rather than at high temperatures.