鼎湖山退化马尾松林、混交林和季风常绿阔叶林土壤全磷和有效磷的比较

土壤全磷和有效磷浓度的变化随林型和季节不同而异,总的来说,其大小顺序为:季风常绿阔叶林> 混交林>马尾松林(林型);夏季>冬季>春季>秋季(季节),有效磷浓度为:秋季>春季>冬季>夏季(季 节)。收割林下层和凋落物这种人为干扰活动对土壤全磷含量的影响不明显,但对土壤有效磷含量具有显著 的影响。在试验开始时(1990年5月),土壤全磷和有效磷浓度在马尾松林保护样地(停止人为干扰)和处理样 地(按当地习惯继续收割林下层和凋落物)间的差异均不显著。经七年多的试验后,土壤全磷浓度在保护样地 和处理样地间仍十分相似,但土壤有效磷浓度在保护样地显著高于处理样地,说明保护样地在停止人为干扰 后相对于继续受干扰的处理样地其林地条件得到了改善,从而使土壤有效磷含量也得到提高。只要停止人为 干扰,鼎湖山退化马尾松林土壤有效磷供应力是可以自然恢复到季风常绿阔叶林的水平。     

The recovery of damaged pine forests in an area formerly polluted by nitrogen

An area in Lithuania containing coniferous stands of Scots pine and Norway spruce that were dead or damaged due to nitrogen pollution by a nitrogen fertilizer plant (JV Achema) was found to have expanded between 1974 and 1989 to a distance of 20 to 25 km northeast of the plant in the direction of prevailing winds. Over the last 10 years, when nitrogen pollution by the plant had decreased, a clear process of recovery of the damaged ecosystems could be observed. The following features of this process as it occurred in damaged Scots pine stands are discussed: (1) refoliation (or decreased defoliation) of damaged trees, where a clear positive trend could be observed; (2) changes in the species composition and in the covering by ground vegetation, where small changes and indication of less-nitrophilous species coverage could be detected; and (3) chemical and acidity changes in Luvisols and Arenosols, where a significant decrease could be seen especially concerning nitrate concentrations.     

Succession of secondary forests affected by pine wilt disease in western Japan followed on vegetation maps

Abstract. Succession, changes in the distribution pattern of forest vegetation, and Pinus forest survival following pine wilt disease were clarified based on phytosociological analysis and vegetation maps. Survival of Pinus forests was restricted to the early successional stages, which were located on ridges and the upper part of slopes. Subsequent to pine wilt disease, the succession progressed from early to late substages of Pinus forest, mixed deciduous and evergreen Quercus, to evergreen Quercus forest. Succession occurs in abandoned pine forests which apparently are in a bad state and are vulnerable to attacks by pine wilt disease.     

Local and microscale distributions of Cenococcum geophilum in soils of coastal pine forests

To clarify the local and microscale distribution patterns of Cenococcum geophilum at soil surfaces in coastal pine forests, we collected soil samples in Pinus thunbergii stands. To investigate the local distribution of C. geophilum, five soil samples were collected randomly to obtain roots of P. thunbergii at four study sites. To examine the microscale distribution of fungi, 19 soil samples were collected from a 5 × 5 m quadrat at a minimum interval of 15 cm. Ectomycorrhizas of P. thunbergii were examined and identified morphologically. C. geophilum mycorrhizas were retrieved from all the sites at the local scale and from all sampling points within a site at the microscale. The occurrence frequency of C. geophilum ectomycorrhizas ranged from 20.0 to 62.6 % at the sites studied. These results suggest that C. geophilum is the dominant ectomycorrhizal fungus and is distributed ubiquitously in coastal pine forests of Japan.     

The effect of fire history in shaping diversity patterns of flower-visiting insects in post-fire Mediterranean pine forests

Fire affects diversity and structure of flower-visitor communities. We explored the effect of fire history on the diversity patterns and structure of the flower-visitor guilds (bees, beetles, flies, sawflies, and wasps), across a post-fire regeneration sequence of pine forests in Rhodes Island, Greece. Fire history was defined by fire frequency and post-fire age of sites. We did not find significant differences in species richness and abundance per guild between fire-history regimes except for the abundance of flies, sawflies and the entire flower-visitor community. Fire strongly affected the community structure of bees, beetles, and sawflies. Some of the most abundant and common species responded significantly to fire in terms of abundance; yet, we observed no significant variation in the abundance of the common species of bees, the most prominent pollinator group, implying that provision of pollination services may not be considerably affected by fire. Long-unburnt sites displayed higher heterogeneity in species composition compared to recently-burnt sites (either burnt once or twice). This pattern deviated significantly from null expectations when analyzing the abundance-based metric of β-diversity and was obscure in the case of the presence/absence-based metric, indicating that fire affected mainly the spatial distribution of individuals, i.e. the main change is not due to species turnover but to changes in relative abundance. Furthermore, the species composition in recently-burnt sites (burnt once in 2008) were more similar than in twice-burnt sites (including areas burnt once between 1984 and 1992, and in 2008), indicating that fire frequency affected post-fire heterogeneity of species composition.     

A technique for determining the stomach poison effect of insecticides used against leaf-eating insects

Methods devised for feeding individual insects with leaf areas bearing known deposits of insecticides are described, and the problems associated with incomplete consumption of the treated leaf portions are discussed. An account is given of the difficulties of applying the technique to small insects and to those with erratic feeding habits.
Experimental data are given to illustrate the effects on insect resistance of the following: (i) rearing conditions, (ii) larval age and body weight, (iii) acute and chronic poisoning, (iv) the diluting effect of the leaf tissue consumed with the poison dose.
The dosage mortality curve for stomach poisons was found to be typically sigmoid: analysis of results by the method of probits (Bliss, 1934) therefore proved satisfactory. Using lead arsenate against fifth-instar larvae of Phlogophera meticulosa the ratio of weight increase to increase in median lethal dose was found to be constant.     

Pyrogenic changes in microelement content in soils and plants from the pine forests of western Transbaikal

The pyrogenic transformation of the microelement content in soils and plants from western Transbaikal (Republic of Buryatia) has been studied. As is found, ground fires, under the studied conditions, lead to the transformation of soil properties and slightly elevated concentrations of Mn, Zn, Cu, and Pb in the surface soil (0–40 cm) and and Mn, Zn, and Pb in plants. It has been also found that the soil Fe: Mn ratio becomes lower. A pyrogenic transformation of vegetation and the soil properties, the elemental composition in particular, is shown to be traced over several years after the fire.     

Runoff and erosion from volcanic soils affected by fire: the case of Austrocedrus chilensis forests in Patagonia, Argentina

Aims

We characterized the runoff and erosion from a volcanic soil in an Austrocedrus chilensis forest affected by a wildfire, and we evaluated the effects of a mitigation treatment.

Methods

Rainfall simulations were performed in the unburned and burned forest, with and without vegetation cover, and under a mitigation treatment.

Results

After the wildfire, the mean infiltration rate decreased from 100 mm?h^?1 in unburned soils to 51 and 64 mm?h^?1 in the burned with and without litter and vegetation cover, respectively. The fast establishment of bryophytes accelerated the recovery of soil stability. Sediment production was negligible in the control plots (4.4 g?m^?2); meanwhile in the burned plots, it was 118.7 g?m^?2 and increased to 1026.1 g?m^?2 in the burned and bare plots. Total C and N losses in the control plots were negligible, while in the burned and bare plots the organic C and total N removed were 98.25 and 1.64 g?m², respectively. The effect of mitigation treatment was efficient in reducing the runoff, but it did not affect the sediment production.

Conclusions

These fertile volcanic soils promoted the recovery of vegetation in a short time after the wildfire, diminishing the risk of erosion.     

黄山地区松树林外生菌根菌资源及生态分布

1998～2003年,对黄山地区松树林下外生菌根菌资源及生态分布进行了调查,鉴定出外生菌根菌43种,隶属于10科17属.其中马尾松林下有43种、黄山松林下有12种.马尾松幼林下的外生菌根菌种类单一,彩色豆马勃、硬皮马勃类为优势菌种;马尾松成熟林下外生菌根菌种类丰富,其优势种类为红菇科、鹅膏菌科、牛肝菌科和鸡油菌科的一些种类.并分析了树种植被对外生菌根菌分布的影响,菌根真菌的分布与温度、湿度及土壤条件的关系.     

Testate amoebas of pine forests in Mexico

The population of testate amoebas in the soils of pine forests in Mexico has been studied. In total, 68 species, varieties, and types of testate amoebas with cosmopolite distribution were found. The species diversity of the testate population includes hygrophilous species that differ from hygrophilous species with Luvisols in higher Andosols. Comparative analysis using the results of one available study of soil testate amoebas from Mexico has been carried out (Bonnet, 1977).     

Development of secondary pine forests after pine wilt disease in western Japan

Abstract. The development of secondary Pinus densiflora (Japanese red pine) forests after pine wilt disease was studied through phytosociological analysis, estimation of forest structure before disease and size-structure, tree ring and stem analyses. Following the end of the disease, the growth of previously suppressed small oak trees was accelerated. This is quite different from the development of forests following fire, which starts with the establishment of pine seedlings. Pine wilt disease shifted the dominance of secondary forests from Pinus densiflora to Quercus serrata oak forest. In pine forests, disturbance by fire is important for forest maintenance. In contrast, disturbance by pine wilt disease leads to an acceleration of succession from pine forest to oak forest.     

Evaluation of secondary forests as alternative habitats to primary forests for flower-visiting insects

Although primary forests are important for biological conservation, the value of secondary forests for forest-dependent organisms needs to be evaluated when habitat restoration is required. We examined whether flower-visiting insects can use secondary forests as alternative habitats to primary forests. In particular, we compared assemblages of bees (Anthophila) and flower longhorn beetles (Lepturinae: Cerambycidae) in young secondary, mature secondary, and primary forests. Our results showed that more bee species were captured in primary and mature secondary forests than in young secondary forests, and flower longhorn beetle species were captured more frequently in primary forests than in mature and young secondary forests. Ordination showed that the communities in the three forest types were not statistically identical, which indicated that secondary forests cannot provide an absolute alternative habitat to primary forests for bees and flower longhorn beetles. However, the results also suggest that as secondary forests mature, more primary forest species would be able to use secondary forests as habitats. This implies that restoration from other land uses, such as monoculture plantations, to secondary forests could help to promote the faunal biodiversity of primary forests.     

Nitrogen mineralisation in podzol soils under boreal Scots pine and Norway spruce stands

N mineralisation was investigated in the mor humus layer of a podzol at a forested catchment area of Saarejärve Lake in Eastern Estonia. The investigated areas were pine (Rhodococcumunderstorey) and spruce (Vaccinium understorey) stands, which are permanent sample plots of an integrated monitoring network. The seasonal pattern of net N mineralisation was studied by incubating undisturbed cores of mor humus (0–8 cm) in buried polyethylene bags in situ. Samples were collected and incubated between July 1996 and April 1998. The period of incubation was approximately 1 month, except for wintertime when incubation lasted till thawing of ground (5 months). The amounts of mineral nitrogen formed during monthly incubations in vegetation period vary considerably (0.4–8.7 kg ha^–1). About 70% of the variation of net ammonification could be explained by environmental factors - temperature, initial moisture and pH. Ammonium was the dominant form of mineral nitrogen, which is typical for mor humus. The rate of nitrification was very low, and most of the annual net nitrification occurred during just one or two months (May–June, October) depending on site and year. Measured annual net N mineralisation was 29.2 kg ha^–1 for the spruce stand and 23.6 kg ha^–1 for the pine stand. These measures were found to be in good accordance with other N-fluxes in the ecosystem.     

辽宁抚顺松材线虫入侵松林内天牛种类调查

【目的】松材线虫Bursaphelenchus xylophilus (Steiner&Buhrer) Nickle的媒介昆虫云杉花墨天牛Monochamus saltuarius Gebler在辽宁省被发现意味着我国北方松林的生态安全正在遭受严重的威胁。明确松材线虫入侵松林内的天牛种类、数目,可以为早期监测松材线虫媒介昆虫和潜在媒介昆虫的种群动态以及预测松材线虫病的发生提供参考。【方法】为了明确天牛广谱型引诱剂、APFI持久增强型松墨天牛高效诱剂、F8型松墨天牛引诱剂及其复配诱芯的诱捕效果,于2019-2020年的5-10月在辽宁省抚顺市的油松林、红松林、落叶松林开展诱捕天牛试验。【结果】将天牛广谱型引诱剂和F8型松墨天牛引诱剂放在同一诱捕器中具有较好引诱效果,每诱捕器捕获的天牛物种数量（油松林18种,红松林14种,共计19种）和天牛样本数量（油松林（18.31±8.86）头/周,红松林（23.44±10.92）头/周）最多。在试验林地共计诱捕到34种共计13307头天牛,其中云杉花墨天牛数量最多,占总诱捕量的67%,褐梗天牛Arhopalus rusticus、锯天牛Prionus insularis、小灰长角天牛Acanthocinus griseus、松皮花天牛Rhagium japonicum分别占总诱捕量的13.2%、6.6%、4.1%和2.7%。【结论】捕获到危害针叶树的天牛8种,包括云杉花墨天牛（优势种）、小灰长角天牛、灰长角天牛Acanthocinus aedilis、褐梗天牛、脊鞘幽天牛Asemum striatum和锯天牛。根据天牛的取食产卵习性推测,小灰长角天牛、灰长角天牛在补充营养的时候可能会传播松材线虫到健康松树上,而褐梗天牛、脊鞘幽天牛和锯天牛羽化成虫后不需补充营养且产卵在衰弱木的树皮缝隙或者表土处,它们有效传播松材线虫的几率较小。     

Litter decomposition in Mediterranean pine forests is enhanced by reduced canopy cover

Plant and Soil - Compare bacterial communities in non-vegetated soils and in the rhizosphere of Ni-hyperaccumulating or Ni-excluding plants from four serpentine sites of the Iberian Peninsula....     

The Sibyla model and development of beech forests affected by air pollution

The paper deals with the health status, production and structure of autochthonous beech stands in the eastern part of the Krkonoše Mts. (Czech Republic). The region was affected by increased air pollution load due to long-range SO₂ transmission from the late 1970s to the early 1990s. In 1980, five research plots were established in long unmanaged beech stands at an optimum stage. Tree coordinates and initial biometrical measurements were made in 1980 and repeated in 2005. The defoliation of individual trees was monitored every year (ICP Forests principles). The actual stand development is compared with the model development worked out by the Sibyla growth simulator in variants with a model of natural mortality and with entering a real mortality of trees. Differences between the stand characteristics of actual and simulated development of forest stands suggest some production losses. The reason to the losses can be seen in the long-term impact of air pollution in the first decade of monitoring and its after-effects on soil quality and worsening health condition of stands. The anticipated acceleration in the onset of the phase of stand disintegration under the influence of air pollution load was not demonstrated.     

Xylem cavitation in two mature Scots pine forests growing in a wet and a dry area of Britain

The xylem cavitation rate, stem water content, stomatal conductance and leaf water potential of mature Scots pine (Pinus sylvestris L.) were compared over a period of 18 months at two sites in Britain where trees were planted from the same seed source. The sites were at Thetford in south-east England, where the climate is relatively warm and dry (average rainfall of 600mm per year), and Aberfoyle in central Scotland, where it is relatively cool and wet (average rainfall of 1500 mm year^?1). In the first year of study (1992) the natural difference between the sites was amplified by a severe drought affecting south-east England. Acoustic emissions (as a result of cavitation) were detected at both sites, but were not an everyday occurrence, and rates depended on short-term meteorological variation. The relative water content (RWC) of the trunk at breast height at Thetford was significantly lower than at Aberfoyle, and declined in parallel with increasing severity of drought. Following the release from drought a gradual increase in RWC was found, but the pre-drought RWC was not attained. The same xylem water potential gradient and stomatal conductance was found at the two sites; but on a diurnal basis, as water potential declined, cavitation rates increased. There was no difference in vulnerability to cavitation or in hydraulic conductance between the sites.     

Green algae in tundra soils affected by coal mine pollutions

Green algal communities were investigated in clean and pollution-impacted tundra soils around the large coal mine industrial complex of Vorkuta in the E. European Russian tundra. Samples were collected in three zones of open-cast coal mining with different degrees of pollution-impacted soil transformation. A total of 42 species of algae were found in all zones. The species richness decreased from 27 species in undisturbed zones to 19 species in polluted zones. Under open-cast coal mining impacts the community structure simplified, and the dominant algae complexes changed. Algae that are typical for clean soils disappeared from the communities. The total abundance of green algae (counted together with Xanthophyta) ranged between 100–120 × 10³ (cells/g dry soils) in undisturbed zones and 0.5–50 × 10³ in polluted zones. Soil algae appear to be better indicators of coal mine technogenic pollution than flowering plants and mosses. Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.