Luo Z.,Beijing Forestry University |
Luo Z.,CAS Institute of Botany |
Sun O.J.,Beijing Forestry University |
Wang E.,CSIRO |
And 2 more authors.
Ecosystem dynamics and the responses to climate change in mangrove forests are poorly understood. We applied the biogeochemical process model Biome-BGC to simulate the dynamics of net primary productivity (NPP) and leaf area index (LAI) under the present and future climate conditions in mangrove forests in Shenzhen, Zhanjiang, and Qiongshan across the southern coast of China, and in three monocultural mangrove stands of two native species, Avicennia marina and Kandelia obovata, and one exotic species, Sonneratia apetala, in Shenzhen. The soil hydrological process of the model was modified by incorporating a soil water (SW) stress index to account for the impact of the effective SW availability in the coastal wetland. Our modified Biome-BGC well predicted the dynamics of NPP and LAI in the mangrove forests at the study sites. We found that the six mangrove systems differed in sensitivity to variations in the effective SW availability. At the ecosystem level, however, soil salinity alone could not entirely explain the limitation of the effective SW availability on the productivity of mangrove forests. Increasing atmospheric CO2 concentration differentially affected growth of different mangrove species but only had a small impact on NPP (≤7%); whereas a doubling of atmospheric CO2 concentration associated with a 2°C temperature rise would increase NPP by 14-19% across the three geographically separate mangrove forests and by 12% to as much as 68% across the three monocultural mangrove stands. Our simulation analysis indicates that temperature change is more important than increasing CO2 concentration in affecting productivity of mangroves at the ecosystem level, and that different mangrove species differ in sensitivity to increases in temperature and CO2 concentration. © 2010 Springer Science+Business Media, LLC. Source
Lu Q.,Shenzhen University |
Zeng X.,Shenzhen University |
Shi J.,Shenzhen University |
Chen L.,Neilingding Futian National Nature Reserve of Guangdong |
And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica
The community structure, species composition, species diversity and succession trend of a mangrove forest in Futian, Shenzhen Bay, China were analysed. Results showed that (1) All the 4-age mangrove communities of the succession process were consisted of Kandelia candel, Aegiceras corniculatum, Avicennia marina, Bruguiera gymnorrhiza and Acanthus ilicifolius ; (2) The community grew rapidly at early succession stage (4a), and kept a fast rate until 17a when its height gradually came to a stable stage, after then it grew very slowly; (3) The community′s stand class increased rapidly and came to the 4th stand class at 4a community, but it arrived at the highest stand class (the 5th stand class) until 56a. So the 4a and 17a communities were distributed in the 2nd to the 4th stand classes, while the 56a and 73a communities were distributed in the 2nd to the 5th stand classes. (4) With the process of succession, the coverage of community increased gradually except that 73a was lower than that of 56a, and the same succession pattern of breast height was observed, while the density declined gradually with succession. The species diversity and community evenness increased gradually, whereas the ecological dominance declined with succession. The similarity of the community showed that there was no significant changes in community species composition during the succession. (5) The changes and succession trend of the community was: Community of K. candel, A. corniculatum ® Community of K. candel ® Community of A. marina, K. candel ® Community of A. marina. © 2014, Science Press. All rights reserved. Source
Lin X.,Jinan University |
Qiong Y.,Neilingding Futian National Nature Reserve of Guangdong |
He H.,Sun Yat Sen University |
JianGang Z.,Jinan University |
And 3 more authors.
The estimation of pollen production is widely used in pollination and reproductive ecology, aerobiology and pollen-vegetation relationship studies. Pollen release is the key step in estimating pollen production and therefore, the technique used to release pollen is critical. Three methods, the drying method (DM), mechanical method (MM) and chemical method (CM), are used to determine the amount of pollen released from anthers. Few studies have compared the results obtained from each method, making it difficult to determine which method is most appropriate in a given situation. In this study, we compared existing methods with a new method that increases the amount of pollen released from anthers. Eight species of mangrove trees from the Neilingding-Futian National Nature Reserve were selected for study. We combined the MM and CM to produce a new method (the ultrasonic method, UM). To determine the best ultrasonic treatment time using the UM, different durations were tested and the various responses were analysed. The relationships between pollen rupture and the ultrasonic treatment time, pollen size, exine thickness and aperture size were analysed. Finally, four methods for pollen release from anthers were compared. The results indicated that the UM could be an efficient method to release pollen from the anther. To avoid pollen rupture, ultrasonic treatment times in the UM should be less than 30 s. The pollen rupture rate was significantly correlated with the ultrasonic treatment time (r = 0.618, p < 0.001) and the aperture size (r = 0.248, p = 0.036). This comparative experiment indicated that the UM can generate a greater pollen yield than other methods while causing less pollen rupture than the MM. Therefore, the UM may be suitable for more plant species and more accurate for pollen production estimates than the existing three methods, particularly when estimating pollen production in all community plants. © 2016 Collegium Palynologicum Scandinavicum Source
Li M.,Sun Yat Sen University |
Li M.,Guangdong Key Laboratory of Plant Resources |
Lu E.,Sun Yat Sen University |
Lu E.,Guangdong Key Laboratory of Plant Resources |
And 8 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica
The invasive plant Mikania micrantha H. B. K., which is native to central and south America, has caused serious damages in southern China, especially in secondary forest. The invasive plant is a fast growing herbaceous vine. Under favorable sunlight and moisture, it can easily climb up, spread on top of other plants, and form a thick cover that intercepts light and adds heavy load to the underneath plants. It possesses strong asexual propagation ability and has many branches that easily produce adventitious roots so that a stem fragment can grow into a new independent individual. In addition, it has huge amounts of tiny and easily wind-dispersed seeds as well as a high germination rate. Damage of primary vegetation is the prerequisite of invasion. This work critically evaluated the control methods and strategies that have been developed and adopted in the past ten years to provide scientific evidences for controlling the invasive plant. Several controlling methods have been used in field and each method has its own advantages and limitations. Physical removal through cutting stems and digging roots is suitable for small areas with proper caring but not for large area. Removal should avoid fruiting period or fragment dropping because they may promote unintentional anthropologic dispersal. Chemical herbicides can be used when immediate outcome is needed, especially to interrupt fruiting, to clear the area for planting tree, and to foster young. It should be cautious that spraying herbicides may pose negative impact on environment; furthermore, it does not change the habitat, and thus, the invasive plant may re-invade after a few years of no proper action followed. Cuscuta campestris, a dodder, is a safe controlling agent and can easily parasitize the invasive plant. The application of dodder is suitable to mildly control the invasive plant or at an area where physical removal or chemical control are not appropriate. The proliferation of dodder is always behind that of invasive plant; manual dispersal of dodder to timely grow and disperse is needed. Community restructuring can suppress the invasive plant permanently. The restructuring creates an environment unsuitable for the invasive plant but proper for some fast growing tree species. Community restructuring is particularly suitable for afforestation area, but it costs more than other methods in short term. Natural enemies control and allelopathic control are promising while most are still at the exploratory stage. In future, more attention should be focused on the exploration of effective natural enemies, the integration of controlling methods, and the revelation of distribution pattern in macro level. The correct strategy to control the invasive plant is as follows: persistency rather than fast result for controlling vast area invasion; prevention of invasion to new areas being utmost important; revision of existing evaluation system to direct controlling from cleaning invaded area to protecting un-invaded area; management priority being addressed on mild invasion area and area that potentially becomes the source of dispersal to surrounding and distance area, spend less control resources to areas that have been severely invaded and to remote isolated area that have few human activities; establishing demonstration plot to promote knowledge of correct controlling methods and strategy, to enhance public awareness and to improve public confidence on successful prevention and control of the invasive species. Source
Ren H.,CAS South China Botanical Garden |
Guo Q.,U.S. Department of Agriculture |
Liu H.,Florida International University |
Liu H.,Fairchild Tropical Botanic Garden |
And 4 more authors.
Journal of Coastal Research
Ren, H.; Guo, Q.; Liu, H.; Li, J.; Zhang, Q.; Xu, H., and Xu, F., 2014. Patterns of alien plant invasion across coastal bay areas in southern China. An understanding of the ways in which levels of invasions by alien species are correlated with environmental factors is helpful to manage the negative impacts of these invasive species. Two tropical coastal areas in South China, Shenzhen Bay and Leizhou Bay, are national nature reserves, but they are threatened by invasive plants. Here, we investigated the level of invasion by exotic plants at both bays, and its relationship with selected environmental factors. We found a total of 34 invasive plant species, 18 of which were present at both bays; among these, 15 species were in terrestrial areas, three were at the ecotone, and one was in the mangroves. The two bays had a similar degree of invasion but were dominated by different species. Three invasive species (Ipomoea purpurea, Wedelia trilobata, and Panicum repens) were abundant at both bays, and only one species, Sonneratia apetala, was present in the mangroves. The number of alien species increased from mangrove to ecotone to terrestrial areas in both bays, while, in proportion, ecotone supported the most alien species in Shenzhen Bay. The relationships between plant invasion and habitat features depended on the variables that were used to measure the degree of invasions. In general, the occurrence of alien species was positively correlated with soil organic carbon and total N content but negatively correlated with the leaf area index and soil salinity. The biomass of alien plants was, on the other hand, positively correlated with total N and soil water content in the soil, and the density of alien plants was not correlated with habitat characteristics. Most of the alien plants originated from tropical America, but a few were from Africa and south Asia. We recommend restoration efforts that include removal of alien species, soil improvement, and the planting of native species. © Coastal Education & Research Foundation 2014. Source