Abundance response of western European forest species along canopy openness and soil pH gradients

In order to better understand the structure and composition of forest plant communities, we aimed to predict the abundance of understory herbaceous species locally at the stand level and according to different environments. For this, we seeked to model species distributions of abundance at a regional scale in relationship with the local stand structure (canopy openness) and regional soil resources (soil pH).Floristic inventories, performed in different light and soil conditions located in 1202 records of north eastern France, were used to analyze the combined effect of canopy openness and soil pH on the abundance of 12 common western European forest species: Anemone nemorosa, Deschampsia flexuosa, Festuca altissima, Hedera helix, Lamium galeobdolon, Lonicera periclymenum, Molinia caerulea, Oxalis acetosella, Pteridium aquilinum, Rubus fruticosus, Rubus idaeus, and Vaccinium myrtillus. Ordinal regression models relating species abundance responses to their environment were developed.For most species (eight out of 12), distribution was significantly affected by canopy openness and soil pH. Differences among low-abundance (i.e. cover <25%) and high-abundance (i.e. cover >25%) responses were noted for 11 species along the canopy openness gradient and four species along the pH gradient. The present study quantifies optimal light and soil nutrient requirements for high-abundance responses and quantifies light and soil nutrients tolerance conditions for low-abundance responses. The combination of both factors highlights the pre-eminence of pH conditions occurrence and canopy openness for species abundance.The models developed by this study may be used to define canopy openness thresholds in function of soil characteristics to control the development of species during forest regeneration. The species-specific reactions on local canopy openness along a regional soil gradient illustrate the need for a species-specific management approach.     

The challenge of conserving grassland insects at the margins of their range in Europe

Insects have experienced higher rates of decline than other popular taxa in the calcareous grasslands of Europe. This paper reviews reasons why insects are so vulnerable to environmental change, particularly at the edges of their range. Case studies of the ant Myrmica sabuleti and the butterflies Polyommatus bellargus and Thymelicus acteon are used to illustrate the mechanisms responsible for this vulnerability and the need for different management regimes to maintain species’ niches in different parts of their range.     

春季杨树苗圃主要地下害虫群落生态位研究

分析了杨树苗圃春季主要地下害虫群落的空间生态位、时间生态位以及时空二维生态位。结果表明:6种主要地下害虫生态位各不相同:在空间维度上,小黄鳃金龟、华北大黑鳃金龟以及阔胫鳃金龟生态位宽度较大,黑绒鳃金龟和沟金针虫生态位宽度较小;小黄鳃金龟与沟金针虫生态位重叠值较大,毛黄脊鳃金龟与沟金针虫重叠值较小。在时间维度上,除毛黄脊鳃金龟生态位宽度较小外,其他地下害虫生态位宽度均较大。在时空维度上,阔胫鳃金龟生态位宽度最大,沟金针虫生态位宽度最小;阔胫鳃金龟与沟金针虫生态位重叠值较大,黑绒鳃金龟与沟金针虫重叠值较小。     

基于Niche GA的灰色模型预测天然气管道腐蚀速率

建立了管道腐蚀预测的基于小生境遗传算法灰色模型,将此预测模型应用于四川气田某输气管道的腐蚀速率和腐蚀深度的预测。预测结果表明,该模型的预测结果误差小,可以用于现场管道的腐蚀预测,是管道腐蚀预测的一种新方法。     

西藏色林错-普若岗日国家公园潜在建设区夏季浮游植物群落生态特征

为了探究色林错-普若岗日国家公园潜在建设区夏季浮游植物群落及优势种生态特征,于2015年和2016年8月对浮游植物群落进行了调查分析,并运用生态位宽度、生态位重叠及生态响应速率等方法测定优势种的生态位量度。结果表明：（1）色林错-普若岗日国家公园潜在建设区共鉴定出浮游植物127种,隶属于3门5纲11目18科35属,其中优势种5种,隶属2门5属,优势种丰度和优势度在不同区域均有差异;（2）泉生菱形藻（Nitzschia fonticola）生态位宽度最大,嗜盐舟形藻（Navicula halophila）生态位宽度最小;（3）浮游植物优势种生态位重叠程度不高,种间竞争弱,群落结构较为稳定;（4）浮游植物优势种呈发展或衰退趋势是不同浮游植物优势种间竞争的必然结果。本研究结果为色-普国家公园潜在建设区浮游植物多样性积累基础数据,为探讨生态位分化理论下的种间关系、资源利用及生态适应机制提供参考。     

Habitat and flower resource partitioning by an exotic and three native bumble bees in central Hokkaido, Japan

Studies of the interspecific relationships between alien and native pollinator species can help forecast the success of alien species as well as assess the extent of disturbance to native plant-pollinator interactions. We examined the habitat and flower resource occupancy by the invasive introduced bumble bee Bombus terrestris and three dominant native bumble bees in central Hokkaido, northern Japan, in relation to a landscape factor (forest cover ratio) and flower morphology with respect to the proboscis length of bees. Three years of monitoring the invasive boundary of B. terrestris indicated that this species, which dominates open agricultural areas, probably will not invade the forests in which the native species dominate. This habitat partitioning likely followed the displacement of the natives by the invader in open agricultural lands. In forested areas, the native species partitioned flower resources on the basis of the relationship between proboscis length and the lengths of the corolla tubes of flowers. However, in open agricultural areas, both the long- and short-tubed flowers were primarily visited by the exotic short-tongued B. terrestris, which foraged illegitimately (by nectar robbing) on long-tubed flowers (Trifolium pratense L.) and legitimately on short-tubed flowers (T. repens L. and Lavandula angustifolia Mill.). The invasion of B. terrestris into open natural vegetation, in addition to open agricultural areas, has recently been reported in Hokkaido. Even though the exotic and dominant native bumble bees partition their habitat according to landscape factors, the invasive bee has the potential to alter the overall interactions within plant-pollinator systems in the regions of open vegetation on Hokkaido Island.     

基于生态位理论的厦门市耕地数量演变及驱动力研究

耕地数量变化及其影响的土地利用结构,对理解城市化过程和区域可持续发展具有重要指示意义。基于生态位态势、生态位扩充与压缩等生态位理论,本文测算了1990—2015年厦门市各种土地利用类型和厦门市六区的生态位宽度与熵,分析了厦门市耕地数量的时空演变特征和机制,探讨了厦门市耕地数量变化驱动因素。研究结果表明：1）1990—2015年,厦门市的耕地数量生态位逐渐下降,年均压缩率1.45%,这与建设用地数量生态位的扩充直接相关。综合来看,厦门市耕地数量生态位的演变处于后期滞缓阶段。2）厦门各区的耕地数量生态位变化与厦门市一致,总体呈下降趋势。耕地面积占有率及耕地面积减少速度在各区之间分异较大,根据各区耕地数量生态位的演变特征可以划分为3类,按成熟度递减排序依次为湖里区和思明区、集美区和海沧区、同安区和翔安区。3）厦门市的耕地与建设用地综合效益生态位差逐渐变大,这驱动了耕地数量生态位的演变,其中经济效益是主导效益。研究结果有助于生态位理论在社会生态领域的发展以及城市区域耕地的保护。     

亚热带低山丘陵区混播冬性牧草-水稻短期草田轮作系统的研究

1991～1994年在亚热带低山丘陵区(四川芦山县)进行的混播冬性牧草-水稻短期草田轮作系统的研究结果表明,混播冬性禾草和豆草与水稻轮作,即意大利黑麦草+紫云英→水稻、意大利黑麦草+南苜蓿→水稻和意大利黑麦草+白三叶草→水稻3个轮作系统在水稻产量高于对照的情况下获得高饲料价值,较充分地利用了禾草和豆草的共生互补作用,改善了土壤肥力状况,提高了农田生态位的利用效率,从而获得了较高的总生产效率。     

右玉盐碱化草地植物生态位特征研究

研究盐碱化草地植物群落特征和演替方向,对其生态系统的恢复或重建以及提高其生产力具有极其重要的作用。试验采用样方法对右玉盐碱化草地的植物种群进行了系统的调查研究,计算其20种主要植物的重要值、生态位宽度及生态位重叠值。结果表明:该盐碱化草地的优势种为赖草,其重要值为0.39,亚优势种为碱茅,重要值为0.35;而生态位宽度值最大的是碱毛茛,为0.9075,其与其他物种的生态位重叠值也较其他物种大,该盐碱化草地生物种群不稳定,演替方向将是杂类草代替禾草的优势地位,该草地的利用价值会下降,如不及时采取有效措施,盐碱化及退化速度将继续增大。     

藏中矿区植物种群生态位特征研究

本文采用样方法以藏中矿区的3种群落为研究对象,对样地的植物种群进行系统调查,并计算其主要植物的重要值、生态位宽度和生态位重叠值。结果表明,不同群落类型优势种非常明显,并且具有较高的生态位宽度和生态位重叠。高寒矿区各植物优势种群与其它种群之间竞争激烈,群落结构极不稳定,群落可能正处于正向演替和逆向演替的拐点。