轮换种植对孟加拉国吉大港山区土壤中真菌和细菌群落的影响

在孟加拉国吉大港山区选择两块研究地,研究轮换种植对土壤中真菌和细菌群落的影响。两块研究地均包含轮换种植和本地社区管理的乡村森林,第一块研究地点选择在兰加马蒂地区,第二块研究地点选择在吉大港的班多尔班地区。在两个地点和不同用途的地块中,其表面土（0-10cm）和地表下土（10-20cm）的土壤质地不同,分别为砂壤和粘土。轮作地的土壤pH和含水量比乡村森林的低。研究结果表明：在兰加马蒂和班多尔班地区,大多数情况下,轮作地的表面土和地表下土壤中的真菌和细菌群落数量比乡村森林的低。在兰加马蒂和班多尔班地区的轮作地中,炭疽菌属（CoHetrotrichum）和镰孢菌属（Fusarium）真菌稀少,而两个地方的不同用途地块中均有细菌球菌属（Coccus）,芽孢杆菌属（Bacillus）和链球菌属（Streptococcus）。在两个地方的不同用途地块中常见的真菌有曲霉属（Aspergillus）、根霉属（Rhizopus）、木霉属（Trichoderma）和青霉菌属（Penicillium）。在其它的土壤区系中,由于轮换种植导致土壤环境退化的程度还需要进一步的研究。     

Study on soils under shifting cultivation and other land use categories in Chittagong Hill Tracts, Bangladesh

Soil samples were collected and analyzed from 25 sites of three hilly regions (Rangamati, Banderban and Khagrachari) for an understanding of the impact of denudation and land use on soils in Chittagong Hill Tracts, Bangladesh. There were natural forests, bushy land, slashed sites, slashed and burnt sites, and the sites prepared for shifting cultivation, one year after shifting cultivation and two years after shifting cultivation. The soils were generally yellowish brown to reddish brown, sandy to sandy clay loam, strongly acid, and well to excessively drained on steep slopes with considerable variation among the sites and land use categories. Bulk density was the highest in sites of one year after shifting cultivation (1.52 g·cm-3) and the lowest in forested sites (1.38 g·cm-3). Water holding capacities were, however, statistically similar in all sites. Organic carbon varied from 0.54% (slashed and burnt sites) to 1.55% (forested sites) and total N ranged from 0.05% (shifting cultivation for one year) to 0.13% (forested sites). Available phosphorus (Bray & Kurtz-2 P) was the maximum in forested sites (12.32 mg·kg-1), and it did not differ significantly in other sites. Contents of available Ca, Mg and K were also higher in the bushy lands and forested sites than cleared and shifting cultivated sites.     

孟加拉国丘陵地带桔园和灌木林地土壤物理性质的比较评价

The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts （CHTs） were evaluated and compared with those of bushy hill forests. Soil samples were collected from three different depths （0-5 cm, 5-15 cm and 15-30 cm）, digging three profiles in each land use for determining moisture content, organic matter content and particle density. Maximum water holding capacity, field capacity, dry and moist bulk density and porosity were determined only for the surface soils. Moisture content at all the soil depths was significantly higher （p≤ 0.05） in orange orchard than in forest on both the slopes. Orange orchard contained lower mean soil organic matter than forest on 55% slope, while it contained higher values on 35% slope compared to forest. The highest value of the above two properties was found at surface soil in both the land uses on both the slopes, decreasing with the increase of soil depth. On both the slopes maximum water holding capacity and porosity of surface soil and particle density at all soil depths were lower in orange orchard compared to those in forest. Field capacity values of surface soil did not show consistency in trend for the differences between the two land uses on both the slopes. Bulk density value of moist and dry surface soil was higher in orange orchard than in forest on both the hill slopes.     

Structure and species diversity of subtropical evergreen broad-leaved forest in northern Okinawa Island, Japan

The structure and tree species diversity of a subtropical evergreen broad-leaved forest in northern Okinawa Island, Japan, were studied. Enumeration of the six sampling plots revealed an average density of 5,580 individuals with DBH≧3.0 cm/ha, having an average basal area of 55 m². The large-size trees of DBH≧20 cm contributed 10% of the total individuals, and 49% of the total basal area. The forest showed a high diversity of tree species, which is comparable to some tropical rain forests. A total of 54 over-story species of 24 families and a total of 63 understory species of 26 families were identified in the six sampling plots. Fagaceae and Theaceae were the most important families;Castanopsis sieboldii, Schima wallichii andDistylium racemosum were the most important species. The diversity index and equitability index of species were 4.15 and 0.72 for the overstory plots, and 4.72 and 0.79 for the understory subplots, respectively. The diversity index for the overstory was significantly correlated to the total basal area of trees over 20 cm DBH (p<0.05) and the importance value ofC. sieboldii (p<0.001), while for understory, the diversity index was not correlated to the structural parameters (allp>0.16). The size distribution pattern and age structure indicated differences in regeneration strategies for canopy dominants. In population dynamics of the succession process,C. sieboldii andD. racemosum were self-maintaining types, andS. wallichii was a gap- or opening-dependent type. This study was made possible by support from the Japanese Ministry of Education, Sciences, Sports and Culture, which provided a Monbusho scholarship to X.N. Xu.     

亚热带常绿阔叶林结构、树种多样性和土壤特性的研究(英文)

采用样地调查法,对日本冲绳岛北部的亚热带常绿阔叶林的林分结构,树种组成以及土壤特性等进行了调查分析。结果表明,该亚热带林具有林冠低矮、小径木多等特点。林分的平均林冠高度仅10m,平均立木密度达5400株·hm2(≥3.0cmDBH),其中胸径小于10cm的立木占64%。林分胸高断面积为54.4m2·hm-2。30个调查样地共出现树种数(≥3.0cmDBH)达80种,分属31个科。根据树种的重要值,Castanopsis sieboldii和Schima wallichii分别为优势树种和亚优势树种。树种多样性指数(H’)平均达3.63,均衡度指数(J’)为0.71,丰富度指数(S’)为4.72。这些多样性指数都随着优势树种重要值的增加而显著降低。土壤养分测定结果表明,该森林的土壤肥力低,异质性大,并可能存在Al毒害。由相关分析知,林分密度和优势树高均与土壤pH值呈显著正相关关系;多样性指数则与土壤交换性K ,Ca2 以及Ca2 /Al3 比呈显著的正相关,而与土壤有机碳,全氮和磷呈显著的负相关。这些结果说明土壤性质是影响冲绳亚热带常绿阔叶林林分结构和树种组成多样性的重要因素。图3表4参38。     

Species Composition,Distribution, and Diversity of Woody Species in a Tropical Dry Forest of India

We investigated the composition of tropical dry forest woody species at adult, sapling, and seedling stages, in terms of plant diversity, distribution, and importance value index (IVI), and identified the dominant and ubiquitous species in the five study sites having variable edaphic properties. Species varied markedly in the composition and IVI at different sites. The semi-evergreen species, Shorea robusta, was dominant at the wettest site at all the three growth stages; at the driest site, highly deciduous species Lannea coromandelica was the dominant adult species and Nyctanthis arbortristis the dominant sapling and seedling species. Soil moisture content (SMC) altered the distribution of about 8% of the adult species. ANOVA indicated significant site-wise differences in the Shannon-Wiener index, Whittaker’s evenness, Margalef’s species richness, and β-diversity for the woody species at all the three stages. The Shannon-Wiener index, Whittaker’s evenness, Margalef’s species richness, and β-diversity were greater in seedlings as compared to adult and saplings of tree species. These variations in species composition and distribution are evidently on account of different levels of SMC as well as habitat heterogeneity as indicated by β-diversity which was independent of SMC.     

森林旅游解说规划中的空间、信息与媒体关系模型构建——以天际岭国家森林公园为例

生态文明建设是中华民族永续发展的千年大计,要促进生态、文化和旅游的相互融合。森林旅游解说作为森林旅游过程中必不可少的传播手段,在我国生态文明建设中发挥着重要的作用。以往的文献中,多从游客角度来研究旅游解说规划,空间视角的相关文献甚少,且研究单一。旅游移动性作为旅游的本质属性,从空间视角认识旅游解说规划中的信息与媒体关系将有助于编制科学的旅游解说规划。以湖南天际岭国家森林公园为例,基于实地访谈法与内容分析法,通过对点-线-功能区-公园-区域等5个空间尺度下的80名游客解说需求与媒体偏好进行研究,构建了森林公园解说规划空间尺度、信息需求与媒体偏好概念模型,具有一定的创新性。研究发现,处于不同空间尺度下的游客对解说信息与媒体偏好存在较大的差异性,并指出游客解说信息需求呈现一定的尺度上升趋势,反之则表现不明显。     

金沟岭云冷杉针阔混交林林分结构研究

以吉林汪清金沟岭林场1 hm2云冷杉针阔混交林数据为研究基础,对样地内树种组成、直径结构以及树种的空间分布结构进行分析。结果表明:1)优势物种云杉Abies nephrole-pis、冷杉Picea koraiensis、枫桦Betula costata大径阶的单木占多数,云冷杉的峰度值小于0,直径分布较为分散,枫桦峰度值大于0,直径分布比较集中。在物种的胸径分布格局解释上,负指数模型的解释程度要优于Weibull模型。2)该群落树种的平均角尺度为0.545,空间分布格局呈聚集分布,3种优势树种的平均角尺度为0.475～0.517,呈现随机分布特征。3)云杉、枫桦的平均混交度较高,而冷杉的平均混交度相对较低。4)样地所有物种的平均大小比数为0.496,3种主要树种的平均大小比数排序为云杉<冷杉<枫桦,表明云杉竞争力最大,冷杉次之,而枫桦的竞争力最小。该林分结构较为复杂,群落内树种以聚集分布为主,所以应调整林分林木分布格局,促进林木向随机分布格局发展,同时伐除上层的"霸王树"以及病腐木、弯曲树等处于竞争劣势的林木,将混交度维持在中度混交,从而尽可能保留维持群落的物种多样性。