Beyond just sea‐level rise: considering macroclimatic drivers within coastal wetland vulnerability assessments to climate change

Due to their position at the land‐sea interface, coastal wetlands are vulnerable to many aspects of climate change. However, climate change vulnerability assessments for coastal wetlands generally focus solely on sea‐level rise without considering the effects of other facets of climate change. Across the globe and in all ecosystems, macroclimatic drivers (e.g., temperature and rainfall regimes) greatly influence ecosystem structure and function. Macroclimatic drivers have been the focus of climate change‐related threat evaluations for terrestrial ecosystems, but largely ignored for coastal wetlands. In some coastal wetlands, changing macroclimatic conditions are expected to result in foundation plant species replacement, which would affect the supply of certain ecosystem goods and services and could affect ecosystem resilience. As examples, we highlight several ecological transition zones where small changes in macroclimatic conditions would result in comparatively large changes in coastal wetland ecosystem structure and function. Our intent in this communication is not to minimize the importance of sea‐level rise. Rather, our overarching aim is to illustrate the need to also consider macroclimatic drivers within vulnerability assessments for coastal wetlands.     

Accelerating the Restoration of Vegetation in a Southern California Salt Marsh

Re-establishing plant cover is essential for restoring ecosystem functions, but revegetation can be difficult in severe sites, such as salt marshes that experience hypersalinity and sedimentation. We tested three treatments (adding tidal creeks, planting seedlings in tight clusters, and rototilling kelp compost into the soil) in a site that was excavated to reinstate tidal flows and restore salt marsh. The magnitude of responses was the reverse of expectations, with tidal creeks having the least effect and kelp compost the most. On the marsh plain, kelp compost significantly increased soil organic matter (by 17% at 0–5 cm; p = 0.026 and 11.5% at 5–20 cm; p = 0.083), total Kjeldahl nitrogen (45% at 5–8 cm; p < 0.001) and inorganic nitrogen (35% at 5–8 cm; p < 0.006), and decreased bulk density (16% at 0–5 cm; p < 0.001 and 21% at 5–8 cm depth; p < 0.001) compared to control plots. Survivorship of kelp compost treated plantings increased, along with growth (> 50% increase in a growth index at 20 months after planting; p < 0.0001). In Spartina foliosa plots, kelp compost did not affect soil organic matter, but plants were taller (by ~11 cm; p = 0.003) and denser (47% more stems; p = 0.003). Planting seedlings 10-cm apart in tight clusters on the marsh plain increased survivorship by 18% (compared to 90-cm apart in loose clusters; p = 0.053), but not growth. Tidal creek networks increased survivorship of Batis maritima and Jaumea carnosa by ≥20% (p = 0.060 and 0.077, respectively). Kelp compost had a strong, positive influence on vegetation establishment by ameliorating some of the abiotic stress.     

盐城滩涂沙棘叶营养成分年动态研究

以2003年4月~10月在盐城滩涂区沙棘(H ipp ophae rham noid es subsp.sinensis)林地采集的沙棘叶为材料,采用高效液相色谱法(HPLC)测定氨基酸、维生素和黄酮类物质的含量,并分别用ICP-M S和ICP-AES方法测定有毒重金属Cd、Pb和其它微量元素的含量.结果表明:(1)C a、K、M g、Zn和F e的含量分别在4.860~12.194g/kg、6.361~11.001 g/kg、2.302~3.833 g/kg、25.5~31.0 m g/kg和211~598 m g/kg干重之间;Pb和Cd的含量分别在0.83~2.13 m g/kg和0.29~0.94 m g/kg干重之间;(2)18种氨基酸总含量在13.33~18.41 g/100g干重之间,其中天冬氨酸、色氨酸和谷氨酸含量较高.(3)维生素C、维生素E、芦丁、槲皮素、异鼠李(黄)素含量分别在124.3~190.5 m g/100 g、4.16~7.97 m g/100 g、141.23~352.67 m g/100 g、6.71~32.62 m g/100 g和1.72~3.79 m g/100 g干重之间;(4)粗蛋白、粗脂肪、粗纤维和粗灰分含量分别在15.16~22.42 g/100 g、4.36~11.94g/100 g、12.34~17.38 g/100 g和4.90~9.81 g/100 g干重之间.沙棘叶含有丰富的微量元素、氨基酸、维生素和黄酮类物质等营养成分,具有较高的营养价值,可作为动物饲养和其它工业利用的原料.     

Are females of Ilyoplax pusilla (Brachyura: Dotillidae) attracted to groups having more waving males?

Males of the dotillid crab Ilyoplax pusilla wave at approaching females during the breeding season. They also, however, often perform waving that is not directed toward any particular individual. This undirected waving is associated with the presence of male neighbors and may function in male–male competition. It may also, however, act as a long-range female attractant. To test whether undirected waving functions to attract females, we conducted a field experiment that manipulated the abundance of waving males. We found that females preferred to approach groups that had more waving males. This suggests that undirected waving by male I. pusilla functions as a long-range courtship signal.     

Clonal integration enhances flood tolerance of Spartina alterniflora daughter ramets

Recently, considerable attention has been paid to the invasion of the clonal plant Spartina alterniflora into coastal wetlands at lower elevations. In this experiment, we tested whether clonal integration improved flood tolerance in S. alterniflora daughter ramets. Daughter ramets at two growth stages (young and old ramets) were flooded to water levels of 0, 9 and 18 cm above the soil surface, and the rhizomes between mother and daughter ramets were either severed or left intact. Biomasses of connected ramets grown in controls or in shallow and deep water treatments were 119%, 108% and 149% higher in the old ramet group than those of severed ramets, respectively, whereas they were 3.0, 3.3 and 11.2 times higher in the young ramet group, respectively. At the end of the experimental period, the shoot height, connected with young ramets, in shallow and deep water treatments increased by 19% and 26%, respectively, over that in the control treatments, whereas the old ramets increased by 11% and 39%, respectively. In contrast, the shoot height of the severed young ramets was 27% and 26% lower in shallow and deep water treatments than in the control treatment, respectively. However, the shoot height of the severed old ramets remained constant with increasing water depth. We conclude that clonal integration enhances the flood tolerance of S. alterniflora daughter ramets, and the trait of clonal integration plays more important roles in severe flooding stress conditions and at early growth stages.     

Is the Variation of the Temperature in an Intertidal Pool Diel or Tidal? A Paradigm for Studying Biological Rhythms in the Tidal Zone

This article analyzes the variations of the temperature recorded in a tidal pool near the half-tide level, in a semilunadian regimen. A model of the temperature variations of the pool, based on diffusional exchange with the sea at high tide and with the air at low tide, shows good agreement with the experimental results. Fourier transform analysis of the variations of the main components of the frequency spectrum during a lunar cycle and for different values of the parameters (temperature variations of the air, level of the pool relative to the tide, exchange coefficients with the air and the ocean) reveals a complex structure. When the tidal component exists, it is stable in power and frequency, but is, in most cases, much smaller than the die! peak. Barring the situations when the tide does not reach the pool for several days, the period of the pool is equal to 24.8 h (the first subharmonic of the tidal frequency), except for the part of the lunar cycle during which the high tide corresponds approximately to the extrema of air temperature: Then the period is lower than 24 h and the power decreases. Overall, the mean period is 24 h, which is coherent with the fact that the driving force of the temperature variations is the sun, while its input in the pool is modulated by the tide. The same results can be applied, with a lesser amplitude of the temperature variations, to larger bodies of water. From these results, it is difficult to decide whether the temperature variations constitute a zeitgeber for circadian or circatidal clocks. The present conclusion is that this parameter seems to be, at best, a very unreliable synchronizer.     

Burrowing behaviour of the softshell clam (Mya arenaria) following erosion and transport

Erosion and transport of juvenile individuals may alter the distribution pattern of intertidal bivalves. The burrowing success of recently transported juvenile softshell clams (Mya arenaria) was studied in a laboratory flume under a wide range of hydrosedimentary environments. Juvenile individuals (5-20 mm) were observed under a simulated 30 min slack tide before initiating the flow for a period of 60 min. Five different free-stream velocities (0, 3, 5, 10 and 24 cm s^− 1) and four sediment types (mud, sandy-mud, sand and gravel) were used. The mean proportion of juvenile clams that initiated (MPI) or completed (MPC) a burial decreased with increasing shell length. Erosion from the sediment was more important in large juveniles suggesting that large juveniles may have more difficulty successfully relocating once transported. The MPI increased with increasing flow speed in experimental runs held at speed < 24 cm s^− 1. This was observed in all sediment types. Most individuals were unable to burrow at 24 cm s^− 1 because they got eroded. The MPC also increased with increasing flow speed in mud, sandy-mud and sand. The MPC's response to flow was more complex in gravel because of a shell length × flow speed interaction effect. Our observations suggest that water movement may induce the burrowing behaviour of recently eroded juvenile clams. Results are discussed in an ecological and aquacultural context.     

Comparative studies of tidal rhythms. VIII. A translocation experiment involving Circalunidian rhythms

One of the earliest experiments that provided support for the exogenous clock hypothesis was a translocation experiment involving fiddler crabs. The activity rhythm of a sample of crabs placed in constant conditions, abandoned (in a week's time) the phase of the tidal cycle to which the crabs had been exposed in nature, and the peaks attuned themselves to the approximate times of lunar nadir and zenith. The study reported in the present paper was an attempt to repeat this interesting and important finding.

The effort at replication was unsuccessful. But other more recent findings of tide‐associated rhythms, such as splitting, uncoupling, and temporary arrhythmicity, were confirmed. And an “ultradian”; rhythm was discovered to exist in conjunction with a typical circalunidian frequency.     

Self-assembled structures for surfactant–inorganic component–water system confined in two flat walls

Lattice Monte Carlo simulations for the surfactant–inorganic component–water system are performed to study the morphologies formation of mesoporous materials in a flat confining space. The effects of component concentration, distance and hydrophilicity of two confining walls are considered in a systematic way and 12 different morphologies are observed. In addition to the well-known morphologies that have been found in the bulk before, such as the cylindrical, spherical and lamellar morphologies, new morphologies such as perpendicular lamellar morphology and bridge morphology are found in the flat confining space. Besides, the ternary phase diagram for the solution composition, the binary phase diagram for the surfactant concentration versus the distance of the two walls and that for different wall–surfactant interactions are given in this work.