当前气候、古气候和生境异质性对中国常绿阔叶木本植物生物地理格局的影响（英文）

Understanding biogeographic patterns and the mechanisms underlying them has been a main issue in macroecology and biogeography, and has implications for biodiversity conservation and ecosystem sustainability. Evergreen broad-leaved woody plants(EBWPs) are important components of numerous biomes and are the main contributors to the flora south of 35°N in China. We calculated the grid cell values of species richness(SR) for a total of 6265 EBWP species in China, including its four growth-forms(i.e., tree, shrub, vine, and bamboo), and estimated their phylogenetic structure using the standardized phylogenetic diversity(SPD) and net relatedness index(NRI). Then we linked the three biogeographical patterns that were observed with each single environmental variable representing the current climate, the last glacial maximum(LGM)–present climate variability, and habitat heterogeneity, using ordinary least squares regression with a modified t-test to account for spatial autocorrelation. The partial regression method based on a general linear model was used to decompose the contributions of current and historical environmental factors to the biogeographical patterns observed. The results showed that most regions with high numbers of EBWP species and phylogenetic diversity were distributed in tropical and subtropical mountains with evergreen shrubs extending to Northeast China. Current mean annual precipitation was the best single predictor. Topographic variation and its effect on temperature variation was the best single predictor for SPD and NRI. Partial regression indicated that the current climate dominated the SR patterns of Chinese EBWPs. The effect of paleo-climate variation on SR patterns mostly overlapped with that of the current climate. In contrast, the phylogenetic structure represented by SPD and NRI was constrained by paleo-climate to much larger extents than diversity, which was reflected by the LGM–present climate variation and topog-raphy-derived habitat heterogeneity in China. Our study highlights the importance of embedding multiple dimensions of biodiversity into a temporally hierarchical framework for understanding the biogeographical patterns, and provides important baseline information for predicting shifts in plant diversity under climate change.     

Threshold sediment flux for the formation of river deltas in Hainan Island,southern China

Journal of Geographical Sciences - The knowledge of geomorphological evolution from an estuary to a river delta is necessary to form the formulation of comprehensive land-ocean interaction...     

典型海域生境修复与生物资源养护研究进展与展望

高强度的人类活动和剧烈的全球气候变化导致了海洋污染加剧、海洋生态系统退化和海洋生物资源衰退,海洋生境修复和资源养护成为世界各国普遍采取的应对措施。本文从生境修复设施与技术、生物资源养护技术和监测管理等方面,综述了典型海域生境修复与资源养护的主要研究进展,并从生物行为控制、承载力提升、设施装备、融合发展和生态系统管理等角度展望了未来研究热点和发展模式,以期为未来海洋生境修复和生物资源养护提供参考。     

长江口邻近海域氮同位素的周日变化特征及其对营养盐过程的指示

长江口邻近海域的氮循环过程一直是近海富营养化研究领域的热点问题, 然而目前较少有针对短周期的调查研究。本文调查了该区域氮、磷、硅等主要营养盐及多种形态的氮稳定同位素的在潮周期周日变化特征。结果显示, NO_3~-、NH_4~+、PO_4~(3-)和SiO_3~(2-)的浓度范围分别为 14.09—55.85、0.21—2.26、0.82—1.08 和 16.80—33.85μmol/L, 而δ~(15)N-NO_3~-、δ~(18)O-NO_3~-、δ~(15)N_P和δ~(13)C_P 等的分布范围分别为 4.7‰—11.1‰、-2.0‰—7.8‰、-1.2‰—7.9‰和-22.9‰— -14.7‰。NO_3~-、PO_4~(3-)和SiO_2~(3-)均与盐度呈现明显的负相关特征, 说明三者的主要来源为长江冲淡水; 4NH(10)则随盐度升高而浓度增加, 且在底层高浓度出现时刻与高盐水团输入时刻一致, 说明外海输入是该区域铵盐的主要来源。另一方面, 氮稳定同位素(δ~(15)N-NO_2~-和δ~(15)N_P)未表现出随盐度的变化规律, 而δ~(18)3O-NO_3~-和δ~(13)C_P 则随盐度升高而增加, 说明淡水输入的同位素值低于海洋水平。通过对比中、高浓度叶绿素水体中NO_3~-、δ~(15)N-NO_3~-、δ~(18)O-NO_3~-的变化特征可以看出, 随NO_3~-浓度降低, δ~(15)N-NO_3~-值升高, 且呈现 6.2‰的分馏系数, 且氧同位素也随之增大, 指示水体中浮游植物对硝酸盐的同化吸收作用。而另一方面, 两种同位素的增加差值表现出△δ~(18)O︰△δ~(15)N1 , 说明硝酸盐在被消耗的同时还发生着补充作用。在较高盐度的水体中, 发现4NH(10)呈现出向硝酸盐的转化趋势并引起δ~(15)N-NO_3~-降低, 指示了底部明显的硝化过程, 与此前的研究结果一致。本文结果以期丰富对河口区氮循环和迁移转化的认知。     

Colonisation of South African kelp-bed canopies by the alien mussel Mytilus galloprovincialis: extent and implications of a novel bioinvasion

The Mediterranean mussel Mytilus galloprovincialis is the most significant invasive alien marine species in South Africa and, although not normally found subtidally, has recently been observed colonising heads and stipes of the kelp species Ecklonia maxima in False Bay. We quantified this invasion and explored its ecological implications. Transects laid across kelp beds revealed that 10.34% of kelp individuals surveyed bore canopy mussels, with kelp heads (10.07%) being far more commonly infected than stipes (0.27%). Twenty kelp individuals with infected heads and 20 with infected stipes were separately collected for more-detailed examination. Wet mass of mussels on these kelp heads ranged from 2.5 to 2 462 g (median 86.4 g, interquartile range 14.8–353.8 g) and that of mussels on the stipes from 7.6 to 3 492 g (median 595.5 g, interquartile range 194.0–955.0 g). Mussel clumps consisted mostly of individuals <40 mm in length. Mussel clumps supported a rich biota of 80 invertebrate and 13 algal species. Larger clumps supported more epibiotic species, and those on stipes more species than those of comparable mass on kelp heads. The mussels and their associated epibiotic species negatively affected kelp buoyancy, but rarely enough to overcome natural buoyancy. Some kelp individuals that had been toppled by the weight of mussels and their epibiotic species, however, were encountered in situ. Implications of this invasion include large increases in animal biomass and species richness in the kelp canopy, plus reductions in kelp buoyancy and increased hydrodynamic drag on infected kelps, increasing their probability of being uprooted. Uprooted kelp individuals can raft long distances, potentially transporting both native and alien species to distant sites.     

Spatial pattern reconstruction of regional habitat quality based on the simulation of land use changes from 1975 to 2010

Reconstruction of the spatial pattern of regional habitat quality can revivify the ecological environment background at certain historical periods and provide scientific support for revealing the evolution of regional ecological environmental quality.In this study,we selected 10 driving factors of land use changes,including elevation,slope,aspect,GDP,population,temperature,precipitation,river distance,urban distance,and coastline distance,to construct the CA-Markov model parameters and acquired the land use spatial data for 1975,1980,1985,1990,and 1995 by simulation based on the land use status map for 2010.On this basis,we used the InVEST model to reconstruct the spatial pattern of habitat quality in the study area and conducted classification division and statistical analysis on the computed habitat degradation degree index and the habitat quality index.(1)The results showed that from 1975 to 2010,the habitat degradation degree gradually increased,and the habitat degradation grade spatially presented a layered progressive distribution.Habitat quality presented a constantly decreasing trend.The high-value zones were mainly distributed in the mountainous areas,while the low-value zones were mostly located in built-up areas.During the period of 1975-2010,low-value zones gradually expanded to their surrounding high-value zones,and the high-value zones of habitat quality tended to be fragmented.(2)The spatial-temporal variation characteristics of habitat quality from 1975 to 2010 showed that the regions with low habitat quality were difficult to be restored and mostly maintained their original state;the regions with poor habitat quality,which accounted for 6.40%of the total study area,continued to deteriorate,mainly around built-up areas;the regions with good and superior habitat quality,which accounted for 5.68%of the total study area,were easily converted to regions with bad or poor habitat quality,thus leading to the fragmentation of the regional habitat.(3)From 1975 to 2010,land use changes in the study area were significant and had a huge influence on habitat quality;the habitat quality in the study area decreased consistently,and the area of the regions with bad and poor habitat quality accounted for more than 60%of the total study area.Construction land was the largest factor threatening habitat quality.     

典型入海口海岸带生态环境质量遥感评价研究——以宝山区为例

为了研究入海口海岸带生态环境质量状况,基于遥感信息技术,从土地利用的角度,构建入海口海岸带生态环境遥感评价体系,通过层次分析法并结合专家咨询法,以上海市宝山区岸线向陆5 km区域为例进行评价,得到各区域综合评价值。结果表明,宝山区入海口海岸带以工矿仓储用地为主,该区域生态环境质量自西向东逐渐下降,在练祁河和马路河之间区域到达最低点,向东开始回升,总体生态环境质量呈较差状态。     

海州湾及邻近海域口虾蛄栖息地适宜性建模的环境变量优化

Habitat suitability index(HSI) models have been widely used to analyze the relationship between species abundance and environmental factors, and ultimately inform management of marine species. The response of species abundance to each environmental variable is different and habitat requirements may change over life history stages and seasons. Therefore, it is necessary to determine the optimal combination of environmental variables in HSI modelling. In this study, generalized additive models(GAMs) were used to determine which environmental variables to be included in the HSI models. Significant variables were retained and weighted in the HSI model according to their relative contribution(%) to the total deviation explained by the boosted regression tree(BRT). The HSI models were applied to evaluate the habitat suitability of mantis shrimp Oratosquilla oratoria in the Haizhou Bay and adjacent areas in 2011 and 2013–2017. Ontogenetic and seasonal variations in HSI models of mantis shrimp were also examined. Among the four models(non-optimized model, BRT informed HSI model,GAM informed HSI model, and both BRT and GAM informed HSI model), both BRT and GAM informed HSI model showed the best performance. Four environmental variables(bottom temperature, depth, distance offshore and sediment type) were selected in the HSI models for four groups(spring-juvenile, spring-adult, falljuvenile and fall-adult) of mantis shrimp. The distribution of habitat suitability showed similar patterns between juveniles and adults, but obvious seasonal variations were observed. This study suggests that the process of optimizing environmental variables in HSI models improves the performance of HSI models, and this optimization strategy could be extended to other marine organisms to enhance the understanding of the habitat suitability of target species.     

长江口南汇边滩冲淤变化规律与机制

根据1842—2004年海图资料分析发现,南汇边滩存在近百年尺度的强烈冲刷—淤积旋回。长江主泓走南港或北港是造成冲刷期"北滩、东滩淤积,南滩、过渡带冲刷"或淤积期冲淤态势反相的主要原因;冲刷期内风暴强度和频数明显多于淤积期,造成冲刷期滩面叠置记忆的是暴风浪成因的"高滩冲刷、低滩淤积"的冲淤态势,而淤积期保存的是弱风浪成因的"高滩淤积、低滩冲刷"叠置增强的剖面特征。尽管三角洲整体冲淤态势的转变主要受流域来沙量的控制,但不同岸段受河口河势分水分沙作用、潮流和波浪等共同作用,明显存在此冲彼淤、冲淤动态调整等特征。已有的入海泥沙含量阈值研究以点代面或以局部代整体,这是造成阈值估算偏高的主要原因。2003年三峡水库开始蓄水后平均年输沙量154 Mt/a已低于低阈值184 Mt/a,但三角洲尚未如预测那样发生由净淤积向净侵蚀的转变。已有的河口水文观察资料显示,水体含沙量也未发生明显下降,这可能是潮控型三角洲潮流对泥沙在河口的再分配起主导作用,并可能由此延长三角洲冲淤转变对入海泥沙量减少的滞后。今后需进一步加强潮控型河口复杂过程的综合研究,提高对泥沙含量阈值估算和应对可能面临的海岸侵蚀及其相关的环境地质灾害的能力。     

Regional scenarios of sea level rise and impacts on Basque (Bay of Biscay) coastal habitats,throughout the 21st century

Global climate models have predicted a rise on mean sea level of between 0.18 m and 0.59 m by the end of the 21st Century, with high regional variability. The objectives of this study are to estimate sea level changes in the Bay of Biscay during this century, and to assess the impacts of any change on Basque coastal habitats and infrastructures. Hence, ocean temperature projections for three climate scenarios, provided by several atmosphere–ocean coupled general climate models, have been extracted for the Bay of Biscay; these are used to estimate thermosteric sea level variations. The results show that, from 2001 to 2099, sea level within the Bay of Biscay will increase by between 28.5 and 48.7 cm, as a result of regional thermal expansion and global ice-melting, under scenarios A1B and A2 of the Intergovernmental Panel on Climate Change. A high-resolution digital terrain model, extracted from LiDAR, data was used to evaluate the potential impact of the estimated sea level rise to 9 coastal and estuarine habitats: sandy beaches and muds, vegetated dunes, shingle beaches, sea cliffs and supralittoral rock, wetlands and saltmarshes, terrestrial habitats, artificial land, piers, and water surfaces. The projected sea level rise of 48.7 cm was added to the high tide level of the coast studied, to generate a flood risk map of the coastal and estuarine areas. The results indicate that 110.8 ha of the supralittoral area will be affected by the end of the 21st Century; these are concentrated within the estuaries, with terrestrial and artificial habitats being the most affected. Sandy beaches are expected to undergo mean shoreline retreats of between 25% and 40%, of their width. The risk assessment of the areas and habitats that will be affected, as a consequence of the sea level rise, is potentially useful for local management to adopt adaptation measures to global climate change.