Revealing regional regeneration projects in three small towns in Aotearoa—New Zealand

We discuss case studies of three South Island small towns: Ashburton, Timaru and Oamaru and their wider local authority jurisdictions, focusing on how local stakeholders are defining the issues facing these places and identifying, prioritising and investing in regeneration initiatives, sometimes with the support of central government and other external agencies. Our key finding is that small‐town regeneration is complex, demands a long‐term local collaborative approach, and significant investment in skills, information sharing and programme development, some of which needs to be provided by external, central government, agencies.     

海洋多毛类动物的再生演化

再生是生物体丢失的组织或器官重新生长和修复的过程,是生物科学的本质问题之一.再生现象在生物界中广为分布,但不同生物的再生能力却存在着巨大差异.虽然近年来再生的分子和细胞机制取得了显著的研究进展,但驱动物种再生能力多样性形成的遗传机制尚不明确.海洋多毛类因其多样且快速演化的再生能力和简单线性的分节结构成为研究再生演化的极...     

基于文献计量方法的国内外城市更新比较研究

采用文献计量方法,利用Citespace工具对国内外城市更新研究进行知识图谱分析,从演化过程、发文期刊和研究机构的特征、研究热点等方面对比国内外城市更新研究的差异。研究表明:①国内外城市更新研究的发文量呈现波动上升的趋势,在快速发展阶段尤为显著,每年发文量分别达到117篇和238篇;②研究文献多集中在城市规划、区域研究、城市设计、建筑学等期刊。相对于国外,国内发文期刊更集中。国内排名前10的期刊发文量占比达46.65%,国外仅29.84%;③国内外的研究机构间初步形成合作网络,但网络联系与合作程度依然较低。相对于国外,国内研究机构间联系更紧密。④国外研究热点集中在伙伴关系与公众参与、绅士化、可持续发展、城市转型和文化创意等方面,国内研究热点体现在旧城改造与房地产开发、历史街区和工业遗产的保护与更新、广州-深圳城市更新的探索与实践、公众参与的初步探讨等方面。     

四川喇叭河自然保护区珙桐群落特征与更新

在对四川喇叭河自然保护区珙桐群落进行生态学调查的基础上,着重分析了该区珙桐群落植物的物种构成、群落结构、重要值排序、simpson指数、Shannon-Wiener指数,以及珙桐群落的生境条件、更新动态等。研究结果表明：(1)喇叭河自然保护区珙桐群落是一种典型的中亚热带中山山地常绿、落叶阔叶混交林植被;适宜分布于温暖、潮湿、雨量充沛、云雾多、日照少、山陡沟深的地段;(2)珙桐群落植物种类丰富、古老、特有性强;(3)珙桐群落垂直结构明显,珙桐构成建群种;草本层发达;(4)该地区珙桐以有性和无性繁殖更新,但有性繁殖能力很低,以无性繁殖更新为主,群落在其分布区内是一种稳定存在的群落类型。     

利用生态学和树轮年代学手段试析柴达木盆地东缘山地森林年龄结构与气候变化的关系

选取柴达木盆地东缘山地尔日格为研究剖面, 对坡面上的祁连圆柏(Sabina przewalskii Kom.)沿不同海拔高度进行采样。在利用交叉定年手段对所有样芯定年之后, 确定了样芯的起始年和结束年(死亡年龄), 然后利用树髓心年龄估算法和研究区域胸高年龄经验值最终确定了树木活体植株开始生长的年龄(长树年龄)。根据研究坡面上树木长树或死树年份随海拔和时间变化的变化规律, 探讨了它们与气候变化之间的可能关系, 从而用来作为树轮宽度重建的佐证手段之一。结果表明: 在森林上部和中部, 随海拔的升高, 树木的年龄呈递减趋势; 在森林下部, 随海拔的降低, 树木年龄趋于年轻化; 整个坡面长树峰值出现在公元1200年左右, 长树主要集中在森林中部的3900~4110m之间; 树木死亡的峰值出现在公元1600年之后的50年间, 死树主要集中在森中上部的4100~4210m之间。同时, 还发现在坡面树木死亡较集中的时期, 森林树木更新数目较低, 尤其是在森林上部; 而通过对不同海拔高度上最老树的生长年龄分析, 发现在坡面长树比较集中的时期, 森林下部有往更低海拔处长树的趋势。将研究坡面长树和死树随时间变化的分布情况与研究区附近利用树轮宽度重建的乌兰过去1000年上年9月到当年4月平均温度和德令哈过去1000年上年7月至当年6月降水量进行对比, 发现在40年尺度上, 高温对应着树木高生长数目, 低温并且降水量由多变寡则对应着树木低生长数目和高死亡数。表明: 温度的升高有利于研究坡面祁连圆柏更新的发生, 森林密度增大, 森林中部幼树更新存活数量最多, 森林下部有往更低海拔处长树的趋势, 森林上限随海拔的升高密度降低、树木趋于年轻化; 反之, 气候干冷, 树木更新条件变差, 受影响的区域主要集中在森林中部-森林林线中上部范围内, 死树相对比较集中。     

条斑紫菜离体组织再生苗的研究

条斑紫菜叶状体离体组织（切块）在一定培养条件下,其营养细胞经过一系列的变化可产生出幼茵。本研究发现切块越小出苗越早、单位面积离体组织出苗量越多。成熟叶状体上靠近雌雄性细胞的区域与其他部位的营养细胞相比形成幼苗较早,离这一区域越远的细胞成苗越晚。离体组织细胞成苗的适宜水温为１５￣１７℃。在２０￣２５℃下部分细胞进行不规则分裂形成深紫红色的细胞团。当降温至１７℃时,它们仍可转化为幼苗。     

Interaction between water flow and oxygen deficiency on growth in the infaunal brittle star Amphiura filiformis (Echinodermata: Ophiuroidea)

Interactions between ‘oxygen concentration’ (normoxia: >80% oxygen saturation, and hypoxia: 18% oxygen saturation) and ‘water flow velocity’ (low: 0.1 cm s⁻¹, and moderate: 0.5 cm s⁻¹) were studied on growth rates in the brittle star Amphiura filiformis in a flow-through aquaria system. Effects of ‘sublethal predation’ on growth rates were investigated as ‘number of amputated arms’ (1 and 3 arms) and ‘amputation of the disk’. A significant interaction between oxygen concentration and water flow velocity was observed in mean arm regeneration rate, but in both flow velocities higher mean arm regeneration rates were observed in normoxia compared to hypoxia. In hypoxia a positive response in arm regeneration rate was observed in moderate flow compared to low flow velocity. In normoxia, however, no response to flow velocity was observed. The latter observation indicates that Amphiura filiformis is able to maintain the ventilation of the burrow at low flow velocities, but in low oxygen concentrations hydrodynamic forces seem to affect growth. A significant interaction between oxygen concentration and disk amputation was observed in both arm and disk regeneration rates, indicating that the disk is the major organ for gas exchange in this species. The number of arms amputated, however, did not affect mean arm regeneration rate. The results obtained in this study suggest that the secondary production in subtidal infaunal populations could be negatively affected by low oxygen concentrations and that this response is even more negative in combination with low flow velocities in the near-bottom water.     

不同更新方式对中亚热带森林土壤理化性质的影响

森林的不同更新方式对森林土壤理化性质有重要影响．本研究通过野外调查探讨中亚热带山区杉木人工林和米槠人促更新林2种不同更新方式下林地土壤理化性质的变化特征,并用土壤退化指数定量描述土壤质量变化．结果表明：杉木人工林土壤表层（0—10cm）容重显著高于米槠人促更新林（P〈0．05）;随土壤深度的增加,杉木人工林和米槠人促更新林土壤有机C、全N、全P、水解N和有效P均逐渐降低．米槠人促更新林表层（0—10cm）土壤有机c比杉木人工林高出15．6％,全N、全P以及水解N和速效P也均表现出人促米槠更新林高于杉木人工林的趋势;土壤退化指数的计算结果表明杉木林土壤质量显著低于米槠人促更新林．     

二次生烃过程中升温速率对生烃途径的影响 --以鄂尔多斯烃源岩生烃动力学研究为例

采用生烃动力学方法对鄂尔多斯已熟烃源岩进行模拟实验,与以往结果有所不同,实验证明在源岩二次生烃过程中,慢速升温并不利于液态烃的生成,而快速升温才更有利于生成液态烃。这可能是因为在慢速升温条件下,有机质可以有足够长时间缩聚成超大基团,而快速升温则易造成中等分子链的断裂,从而导致快速升温时抽提物产率高于慢速升温。因此,升温速率的差异对有机质的演化影响不只是影响反应速率,更重要的是会改变反应路径,从而对于像鄂尔多斯这样存在二次生烃的盆地,应适当重视那些高地温梯度区块石油资源的寻找。     

Mapping post-fire forest regeneration and vegetation recovery using a combination of very high spatial resolution and hyperspectral satellite imagery

Careful evaluation of forest regeneration and vegetation recovery after a fire event provides vital information useful in land management. The use of remotely sensed data is considered to be especially suitable for monitoring ecosystem dynamics after fire. The aim of this work was to map post-fire forest regeneration and vegetation recovery on the Mediterranean island of Thasos by using a combination of very high spatial (VHS) resolution (QuickBird) and hyperspectral (EO-1 Hyperion) imagery and by employing object-based image analysis. More specifically, the work focused on (1) the separation and mapping of three major post-fire classes (forest regeneration, other vegetation recovery, unburned vegetation) existing within the fire perimeter, and (2) the differentiation and mapping of the two main forest regeneration classes, namely, Pinus brutia regeneration, and Pinus nigra regeneration. The data used in this study consisted of satellite images and field observations of homogeneous regenerated and revegetated areas. The methodology followed two main steps: a three-level image segmentation, and, a classification of the segmented images. The process resulted in the separation of classes related to the aforementioned objectives. The overall accuracy assessment revealed very promising results (approximately 83.7% overall accuracy, with a Kappa Index of Agreement of 0.79). The achieved accuracy was 8% higher when compared to the results reported in a previous work in which only the EO-1 Hyperion image was employed in order to map the same classes. Some classification confusions involving the classes of P. brutia regeneration and P. nigra regeneration were observed. This could be attributed to the absence of large and dense homogeneous areas of regenerated pine trees in the study area.