广东省种子植物分布新资料

报道广东省种子植物分布新记录2属——甜茅属(Glyceria R. Br.)及锦鸡儿属(Caragana Fabr.)，2个新记录种——甜茅[Glyceria acutiflora subsp. japonica (Steud.) T. Koyama et Kawano]及锦鸡儿[Caragana sinica (Buc’hoz) Rehder]，均发现于丹霞山国家级自然保护区。新记录的发现对于研究丹霞山的区系发生具有一定指示意义。     

广东特有国家保护植物丹霞梧桐资源调查与保护研究

通过对文献、网络资源数据库(植物志、标本平台、图像库等)和专著分析考证,结合全部产地的野外实地考察,对国家II级重点保护野生植物丹霞梧桐(Firmiana danxiaensis)的分类学地位与形态特征、产地与生境、标本记录、研究进展及致危因素等进行综述,以期为该物种的保护提供科学依据。自1986年在广东仁化丹霞山采到模式标本和1987年命名丹霞梧桐以来,至今已过去30多年,其记录范围从最初的仁化县丹霞山,2014年扩展到南雄市全安镇和古市镇,再到2019年新记录的英德市英城镇和横石塘镇,生境也从丹霞地貌特有扩展至与石灰岩地貌共有。丹霞梧桐种群的保护需综合就地保护、迁地保护,以及加强科学研究等措施。     

广东省种子植物分布新资料(二)

报道广东省种子植物分布新记录5种——竹茎兰(Tropidia nipponica Masam.)、二色鸭跖草(Commelina bicolor D. Q. Wang & M. E. Cheng)、猫爪草(Ranunculus ternatus Thunb.)、繁缕景天(Sedum stellariifolium Franch.)和福参(Angelica morii Hayata),均发现于广东丹霞山国家级自然保护区。新记录不仅丰富了广东省的种质资源,对于丹霞山的区系发生研究也具有一定指示意义。     

Influence of urbanization on ant distribution in parks of Tokyo and Chiba City,Japan I. Analysis of ant species richness

To investigate how progressive urbanization influences the distribution of ant species in cities, I compared the ant species richness in urban parks of different areas and ages of Tokyo, the most intensively developed urban region in Japan, and its developing neighbor, Chiba City. A total of 43 ant species were found from 98 parks. Multiple regression analysis revealed that park area and age had a positive effect on the number of ant species in the parks and that the parks in Tokyo contained fewer species than did comparable parks in Chiba. Thus, the progression of urbanization reduces ant species richness in urban parks, most likely because it isolates the parks from the surrounding area. Next, in order to examine the relationships between the types of landform modification and the ant distribution in urban areas, I compared the ant species richness in urban parks of Chiba City among different landform types (upland + terraces, lowlands, cut and fill, banking, and reclamation). This study showed that the parks in the reclaimed lands and lowlands contained fewer ant species than did parks in other areas. The reason for this decline of ant fauna is discussed.     

Plant biodiversity in the Saint Catherine area of the Sinai peninsula, Egypt

This study focuses on plant species richness, taxonomic diversity, and endemism of the Sinai peninsula as a whole and Saint Catherine area in particular. Beta diversity was also measured using _T to represent the biotic change between different landforms in the St. Catherine area. The peninsula supports about 1285 species including the infraspecific taxa of which about 800 species (also including the infraspecific taxa) are recorded in the southern Sinai south of El-Tih Desert. The present study reveals that southern Sinai is more diverse as compared with the Sinai peninsula as a whole. Southern Sinai also supports more than the expected numbers of rare and very rare species (about 62%) and about 4.3% endemic species. Beta diversity between different landforms in the St. Catherine area reflect a large biotic change between slopes and terraces on the one hand and between terraces and ridges on the other. Finally, the study recommends appropriate management of the peninsula and more research for the management requirements of the numerous endemic and rare species in the Sinai peninsula.     

Ecological effect on the hilltop of Danxia Landform

The hilltop ecological effect of Danxia Landform generated by the distinct physiognomy and topography was investigated. The characteristic differences in ecological factors, community structure and species ecotype between hilltop and foot gulch and those of adjacent non-Danxia Landform were determined. The results showed that the mean daily temperature on the hilltop was higher than that at the foot gulch. But the average relative humidity and community diversity on the hilltop were lower than those at the foot gulch. In contrast to those on the hilltop, plants at the foot gulch showed stronger tropical character. All of the characteristics above were different from those in other landforms. In addition, ecotypic differentiations in leaf area, specific leaf area, bark, height under branch and crown width were found in the studied species between the hilltop and the foot gulch. Moreover, the hilltop of Danxia Landform was thought to be of significance in the scientific research of ecotype, island biogeography and adaptive evolution. Further studies are needed in order to better understand the universality of ecological effect on the hilltop of Danxia Landform.     

丹霞地貌沟谷生态效应

以广东省丹霞山为研究实例,探讨丹霞地貌特殊的沟谷生态效应.结果表明,丹霞地貌的特殊沟谷生态效应体现在以下两个方面:第一是丹霞地貌演变过程中形成了众多石峰隆起和沟谷凹陷,特殊的地貌环境使得沟谷中的生态因子与其它非丹霞地貌开阔区域产生差异,小气候相对封闭,水湿条件极好,为喜高温高湿的热带物种提供了较好的生存环境;沟谷所处位置的地理环境,如四周崖壁的光滑程度会影响到太阳光反射到沟谷的光强,这些都会对沟谷中的温湿度产生影响.第二是丹霞地貌特殊的生态条件,为沟谷地带孕育出一批热带性较强的分类群提供了可能,与相近纬度的诸多植被相比,丹霞地貌植物区系热带性明显增强,热带分布区类型所占比重比同纬度区域要大10%以上,大多数沟谷中热带性物种分布现象比较明显,藤本分布较多,蕨类植物也较丰富,耐水湿的植物区系发育良好;这实际上造成了植物水平分布上的移位,使中亚热带区域中分布有南亚热带甚至热带区域的物种,出现了由于其特殊的沟谷地貌效应而形成的与其地貌条件保持协调和平衡的演替顶级群落类型,称为地貌顶级群落.     

丹霞地貌山顶生态效应

首次探讨了丹霞地貌山顶生态效应现象,揭示特殊的地貌、形态所产生的特殊生态现象.测定广东省丹霞山宝珠峰和海螺峰的山顶的生态因子特征、群落结构特征和物种生态型特征,并与山脚的群落与种群以及相近非丹霞地貌区作比较.结果表明,山顶的平均温度高于山脚沟谷,平均湿度小于山脚沟谷,群落物种数和物种多样性均小于山脚沟谷.相比山顶而言,山脚沟谷的植物有很强的热带性.这些特征都有别于一般非丹霞地貌山地.另外,在山顶和山脚调查的几个种群在叶面积、比叶面积、树皮、枝下高和冠幅等方面,均出现了生态型的差异.讨论了丹霞地貌山顶对生态型研究、岛屿理论研究和适应性进化研究的科学意义.     

牛耳朵传粉生物学研究

苦苣苔科(Gesneriaceae)报春苣苔属(Primulina Hance)是一个近年来备受关注的类群,其纷繁复杂的物种多样性和属下种间的特有分布引起了分类学家和植物学研究者的极大兴趣。该属除了极少数的物种如牛耳朵[(Primulina eburnea(Hance)Y. Z. Wang)]以外,绝大部分的物种为狭域分布或地方特有种,其分布范围很窄。为了揭示牛耳朵的传粉生物学和繁育系统对其生殖过程和拓殖能力的影响机制,作者系统地研究了牛耳朵的开花物候、花粉与柱头活性、访花昆虫的种类和访花行为、花粉胚珠比、OCI指数和套袋实验结实率,探究其传粉等生殖过程对牛耳朵的广布是否有正面影响。结果表明:牛耳朵的自然花期是3—5月,全花期约45 d,其中盛花期约20 d,单花期6～8 d; 开花后1～2 d花粉活力最强,开花前柱头没有可授性; 花粉胚珠比为537; 杂交指数为5; 去雌套袋、去雄套袋均无法结实,说明本种不存在无融合生殖; 与自然授粉相比,自花授粉结实率略低,异花授粉结实率略高,说明自交亲和; 牛耳朵的主要传粉者是花条蜂(Anthophora florea)和熊蜂(Bombus sp.)。花蜜产量较高、花粉量较大、花粉活力较强等特点,有利于牛耳朵完成传粉和结实的整个繁殖过程。因此,这一结果显然有利于牛耳朵的拓殖进而广布在我国华南至西南地区的喀斯特地区。     

基于地貌类型的中国东海大陆海岸带景观动态分析

基于东海地貌信息数据和6期景观数据,研究1990—2015年东海大陆海岸带地貌类型与景观动态变化特征,分析各地貌类型下景观格局时空分布规律。结果表明:(1)东海海岸带以丘陵地貌为主,其次是小起伏山地、平原、台地和中起伏山地。景观类型林地占主导,其次为耕地和建设用地。(2)平原、台地和丘陵地貌景观变化以耕地转为建设用地为主,小和中起伏山地则以草地转林地为主。(3)不同地貌单元下的景观变化剧烈程度依次为:平原台地丘陵小起伏山地中起伏山地,2005—2015年景观变化叠合度小于1990—2005年,景观变化剧烈程度下降。(4)地貌类型对景观分维数和稳定性指数影响差异较大,平原上水域分维数值最大,台地和丘陵耕地分维数最大,小起伏山地未利用地分维数最大,中起伏山地建设用地分维数最大,稳定性指数相反。耕地在海拔较低的地貌类型中趋于稳定,林地和草地多分布在海拔较高丘陵和山地,水域和建设用地在平原地区分维数最大,稳定性更强。