Zonation of spiders (Araneae) and carabid beetles (Coleoptera: Carabidae) in island salt marshes at the North Sea coast

The specific communities of spiders and carabid beetles of island salt marsh habitats of the East Frisian Island chain at the German North Sea coast were investigated. During the vegetation periods of 1997 and 1998 three pitfall trapping transects were installed on the islands of Borkum and Wangerooge. Within the salt marshes, transects extended from 0 m to 175 m. Elevation gradients varied between 10 cm and 232 cm above MHT (mean high tide). On Borkum, 35 traps were exposed in two transects, on Wangerooge 25 traps were placed in one transect. Three to five elevations above MHT were investigated per transect, each one with five traps. Highest species numbers were recorded in the higher elevated salt marshes. In contrast, highest activity values were noticed in the medium elevated salt marshes. Within both groups, spiders and carabids, four communities were distinguished by indirect gradient analysis. Indicator species were assigned to the different communities that were mainly assorted to different elevations of the salt marshes. Thus, the communities of both taxa corresponded well to the vegetational formations. The importance of sea level rise for structuring the communities of salt marsh arthropods is discussed. Overall, still great uncertainties exist on how arthropod communities and salt marshes themselves will develop.     

Quantifying the cleanliness of glass capillaries

I used capillary rise methods to investigate the lumenal surface properties of quartz (fused silica, Amersil T-08), borosilicate (Corning 7800), and high-lead glass (Corning 0010) capillaries commonly used to make patch pipets. I calculated the capillary rise and contact angle for water and methanol from weight measurements. The capillary rise was compared with the theoretical maximum value calculated by assuming each fluid perfectly wetted the lumenal surface of the glass (i.e., zero contact angle, which reflects the absence of surface contamination). For borosilicate, high-lead, and quartz capillaries, the rise for water was substantially less than the theoretical maximum rise. Exposure of the borosilicate, lead, and quartz capillaries to several cleaning methods resulted in substantially better—but not perfect—agreement between the theoretical maximum rise and calculated capillary rise. By contrast, the capillary rise for methanol was almost identical in untreated and cleaned capillaries, but less than its theoretical maximum rise. The residual discrepancy between the observed and theoretical rise for water could not be improved on by trying a variety of cleaning procedures, but some cleaning methods were superior to others. The water solubility of the surface contaminants, deduced from the effectiveness of repeated rinsing, was different for each of the three types of capillaries examined: Corning 7800>quartz>Corning 0010. A surface film was also detected in quartz tubing with an internal filament. I conclude that these borosilicate, quartz, and high-lead glass capillaries have a film on the lumenal surface, which can be removed using appropriate cleaning methods. The surface contaminants may be unique to each type of capillary and may also be hydrophobic. Two simple methods are presented to quantitate the cleanliness of glass capillary tubing commonly used to make pipets for studies of biological membranes. It is not known if the surface film is of importance in electrophysiological studies of biological membranes.     

China in Laos: Enclave spaces and the transformation of borders in the Mekong Region

Where China Meets Southeast Asia: Social and Cultural Change in the Border Regions edited by Grant Evans et al., is among the few works that take borderlands between China and mainland Southeast Asia seriously. A major contribution of this collection of border studies is its attempt to understand how border experiences and the process of bordering have changed since the early 1990s. Various Chinese–local interactions are explored in this book, with an emphasis on complex local responses to border transformations and diverse forms of mobility and network building. This article further examines the role of China and the Lao state, and the new wave of Chinese movement at the border. In establishing an economic integration that spills across the region, the penetration of Chinese power has been effective. The consequent retreat of the Lao state at the border has not only put an end to the old frontier but turned various borderlands into an estranged space of neoliberal enclave.     

海平面上升对生态系统服务价值的影响及适应措施

海平面上升导致了海岸线后退、沿海侵蚀、风暴潮加强、生物栖息地改变、湿地变迁等,引起了近海域生态系统服务价值的变化。以美国Hillsborough County为研究区域,应用SLAMM模型,模拟了海平面从2010年—2100年上升1m的情景下各类用地面积的变化,利用效益转移法评价了生态系统服务价值的变化。结果表明:1旱地面积减少3037 hm~2,湿地面积增加3037hm~2,其中河口水域、滩涂、盐沼、定期洪水沼泽面积大幅度增加;季节性洪水沼泽、潮汐淡水沼泽、河流潮汐、沙滩面积大幅度减少,其它类型湿地受影响较小。2湿地总面积的增加反而导致了生态系统服务价值总量的降低,从2010年的61672万美元降低到2100年的61548万美元,这是由于净水湿地和沙滩大面积损失引起的;其中艺术娱乐、水调节、气候调节、文化精神价值将下降,水供应、栖息地保护、干扰调节和废物处理价值将上升。3防护、适应、后退3种措施分别降低、不影响、提升了生态系统服务价值,应根据其适用范围综合应用以制定应对海平面上升的适应性措施。     

模拟海平面上升对红树植物秋茄的影响

研究了壤质沙土 (粗质土 )和粘土 (细质土 )条件下红树植物秋茄 (K andelia candel)对水位上升和淹水时间延长的反应。模拟海平面上升 30 cm导致红树林土壤的酸化 ,且细质土的酸化比粗质土严重 ;秋茄繁殖体的萌苗速度明显加快 ;促进秋茄的早期生长 ,尤其是导致最初 2个月茎高生长的增加 ,然而 ,后 2个月秋茄的相对生长率并不因水位的升高而增加 ;地下部 /地上部生物量比减小 ,在粗质土中尤为如此 ;幼苗粗根比例明显增加 ;叶片叶绿素 a/ b比值下降。在微型盆栽试验条件下 ,无论是高水位还是低水位 ,所有的秋茄繁殖体均成功萌发且幼苗在整个试验期间均成活。在野外条件下 ,秋茄幼苗成活率在高水位和低水位条件下均高达 90 %以上。野外条件下 ,无论是经胚轴萌发还是幼苗移栽的幼苗 ,最初 4个月的茎高生长均为低潮区高于高潮区 ,与微型试验结果相同。微型盆栽试验和野外种植试验均表明 ,海平面上升 30 cm对秋茄的萌发和早期生长具有促进作用     

在水生与气生状态下石莼光合作用对无机碳的响应

潮间带海藻光合作用总是处于水生 (高潮时 )与气生 (低潮时 )两种连续变化的环境状态下进行。对汕头沿岸常见的潮间带海藻石莼 (UlvalactucaL .)在水生和气生不同状态下光合作用对无机碳的响应特性进行了比较研究。在水生状态下 ,现有海水中溶解性无机碳浓度能充分饱和 (10℃和 2 0℃时 )或接近饱和 (30℃时 )石莼的光合作用 ;而在气生状态下 ,石莼光合作用受大气CO2 浓度的限制 ,且这种限制作用在较高温度 (2 0 - 30℃ )下比在低温(10℃ )下更严重。在 10℃和 2 0℃时 ,石莼在气生状态下比在水生状态下具有更高的碳饱和最大光合速率 ;而在30℃时 ,石莼在这两种状态下的碳饱和光合速率相似。石莼光合作用的Km(CO2 )值在气生状态下比在水生状态下高 ;而在气生状态下石莼对CO2 的表观光合导度远小于其在水生状态下的值。认为大气CO2 浓度升高将通过促进石莼在气生状态下的光合作用而增加其初级生产力。     

The regulation of xanthophyll cycle activity and of non-photochemical fluorescence quenching by two alternative electron flows in the diatoms Phaeodactylum tricornutum and Cyclotella meneghiniana

Intact cells of diatoms are characterized by a rapid diatoxanthin epoxidation during low light periods following high light illumination while epoxidation is severely restricted in phases of complete darkness. The present study shows that rapid diatoxanthin epoxidation is dependent on the availability of the cofactor of diatoxanthin epoxidase, NADPH, which cannot be generated in darkness due to the inactivity of PSI. In the diatom Phaeodactylum tricornutum, NADPH production during low light is dependent on PSII activity, and addition of DCMU consequently abolishes diatoxanthin epoxidation. In contrast to P. tricornutum, DCMU does not affect diatoxanthin epoxidation in Cyclotella meneghiniana, which shows the same rapid epoxidation in low light both in the absence or presence of DCMU. Measurements of the reduction state of the PQ pool and PSI activity indicate that, in the presence of DCMU, NADPH production in C. meneghiniana occurs via alternative electron transport, which includes electron donation from the chloroplast stroma to the PQ pool and, in a second step, from PQ to PSI. Similar electron flow to PQ is also observed during high light illumination of DCMU-treated P. tricornutum cells. In contrast to C. meneghiniana, the electrons are not directed to PSI, but most likely to a plastoquinone oxidase. This chlororespiratory electron transport leads to the establishment of an uncoupler-sensitive proton gradient in the presence of DCMU, which induces diadinoxanthin de-epoxidation and NPQ. In C. meneghiniana, electron flow to the plastoquinone oxidase is restricted, and consequently, diadinoxanthin de-epoxidation and NPQ is not observed after addition of DCMU.     

Re-establishing a saltmarsh vegetation structure in a changing climate

Summary A major management decision in an ecological restoration or rehabilitation project is whether supplementary planting or natural vegetation regeneration is the better alternative or if a combination can be applied. Management decisions are further complicated when the project involves saltmarsh as tidal cycles, the effects of salinity and sea level rise add to the complexity of decisions. The ecological values of the saltmarsh community in Australia were only recognized relatively recently but the endangered ecological community listing in 1994 (under the New South Wales Threatened Species Conservation Act 1995) highlighted the need to protect, rehabilitate and restore saltmarsh. This project measured vegetation change after soil profile reconstruction in saltmarsh surrounding Sponsors Lagoon, Fingal Peninsula in north coastal New South Wales, Australia. Restored sites (planted and non‐planted) were compared with nearby disturbed (control) and reference sites. The dominant species in the community to be restored were Saltwater Couch (Sporobolus virginicus), Suaeda (Suaeda australis), Sarcocornia (Sarcocornia quinqueflora ssp. quinqueflora and Sea Rush (Juncus kraussii ssp. australiensis). Changes in percentage cover of the species in the first three years after soil reconstruction work showed that the dominant Saltwater Couch established only from vegetative growth arising from remnant vegetation but there was strong seedling regeneration of several other species. It was concluded that planting is important for species that are less vagile, in larger, denuded parts of this site where their resilience is lower and natural regeneration potential is limited. An understanding of the biology of the individual species is therefore likely to be essential in saltmarsh restoration projects. A combination of techniques, incorporating planting of slower establishing species and encouragement of seed‐germinated colonizers is useful for initial site stabilization and progressive ecological recovery at this site. The inclusion of migration zones in the planning phase will allow for the long‐term viability of this restoration project.     

Zonation of mangrove flora and fauna in a subtropical estuarine wetland based on surface elevation

In the context of sea‐level rise (SLR), an understanding of the spatial distributions of mangrove flora and fauna is required for effective ecosystem management and conservation. These distributions are greatly affected by tidal inundation, and surface elevation is a reliable quantitative indicator of the effects of tidal inundation. Most recent studies have focused exclusively on the quantitative relationships between mangrove‐plant zonation and surface elevation, neglecting mangrove fauna. Here, we measured surface elevation along six transects through the mangrove forests of a subtropical estuarine wetland in Zhenzhu Bay (Guangxi, China), using a real‐time kinematic global positioning system. We identified the mangrove plants along each transect and investigated the spatial distributions of arboreal, epifaunal, and infaunal molluscs, as well as infaunal crabs, using traditional quadrats. Our results indicated that almost all mangrove forests in the bay were distributed within the 400–750 m intertidal zone, between the local mean sea level and mean high water (119 cm above mean sea level). Mangrove plants exhibited obvious zonation patterns, and different species tended to inhabit different niches along the elevation gradient: Aegiceras corniculatum dominated in seaward locations while Lumnitzera racemosa dominated in landward areas. Mangrove molluscs also showed distinct patterns of spatial zonation related to surface elevation, independent of life‐form and season. The spatial distributions of some molluscs were correlated to the relative abundances of certain mangrove plants. In contrast, the spatial distributions of crabs were not related to surface elevation. To the best of our knowledge, this is the first study to explicitly quantify the influences of surface elevation on the spatial distributions of mangrove fauna. This characterization of the vertical ranges of various flora and fauna in mangrove forests provides a basic framework for future studies aimed at predicting changes in the structure and functions of mangrove forests in response to SLR.