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Land degradation and soil erosion, intensified by frequent intense hydro-meteorological events, pose significant threats to ecological processes. In response to the environmental challenges, there is a growing emphasis on employing Nature-Based Solutions (NBS), such as Soil and Water Bioengineering (SWBE) techniques, which promote a sustainable approach and materials for the restoration of natural areas damaged by climate events, unlike traditional "grey" engineering works. However, the effective implementation of SWBE interventions requires a multidisciplinary monitoring approach, considering engineering, geological, ecological, biological, and landscape aspects. The success of these interventions depends on evaluating both short-term stabilities provided by the non-living supporting structure and the long-term development of vegetation introduced during the work. Monitoring should regard structural integrity assessments, vegetation evolution studies, and analyses of root system efficiency (distribution, mechanical characteristics, etc.). This study wants to fill the research gap in SWBE management by proposing a comparison of two study techniques for a root system development evaluation, within a multi-approach methodology for the assessment of these interventions in terms of soil stability and natural evolution. The paper provides insights into geotechnical analysis within a shallow landslide, comparing two different methods for the evaluation of root system evolution. Direct methods (RAR) and indirect methods (ERT) were used for root development monitoring and then compared. Vegetation development was assessed by NDVI parameter by analysing Landsat satellite images. An overall analysis of the data obtained from monitoring the study area shows good plant development, thanks to the SWBE intervention, which in addition to the slope stability effect contributes to better water regulation and initiates a natural ecological succession. The findings contribute to advancing the understanding of the effectiveness of SWBE techniques, offering valuable information for future bioengineering projects and environmental conservation efforts, and promoting them as sustainable techniques for natural recovery. [ABSTRACT FROM AUTHOR]

The Nord-Pas-de-Calais Coalfield is formed by an almost continuous succession of upper Carboniferous deposits, from which an extremely diverse macroflora has historically been described. Recent evidence has highlighted a clear pattern of changing species diversity, showing some differences from what is seen in other coalfields of Variscan Euramerica. We further study this significant macroflora, focusing on the biostratigraphical changes and their palaeoecological implications. Clustering and ordination analyses have indicated key floral discontinuities that enable the standard regional macrofloral biozones to be recognized in the Nord-Pas-de-Calais Coalfield. By combining these results with the previous diversity studies, six distinct phases in the evolution of the coal swamp vegetation in north-eastern France can be identified: (1) an initial invasion of peat substrate vegetation in the earliest Langsettian; (2) a rapid diversification of the clastic substrate vegetation in the early-middle Langsettian; (3) a more gradual diversification of the vegetation of both clastic and peat substrates during the late Langsettian to middle Duckmantian glacial phase C3; (4) the appearance of more characteristically late Westphalian, but less diverse floras during the late Duckmantian to early Bolsovian C3-C4 interglacial phase; (5) a marked increase in species diversity in the middle-late Bolsovian, coinciding with the onset of the C4 glacial phase; and (6) a marked reduction in species diversity, and the appearance of new medullosaleans and marattialeans in the Asturian, possibly linked to climate change. The evidence clearly shows how this palaeotropical swamp vegetation was responding to climate change and orogenic landscape changes during Westphalian times. [ABSTRACT FROM AUTHOR]

Vegetation evolution (VEGE) is a newly proposed meta-heuristic algorithm (MA) with excellent exploitation but relatively weak exploration capacity. We thus focus on further balancing the exploitation and the exploration of VEGE well to improve the overall optimization performance. This paper proposes an improved Q-learning based VEGE, and we design an exploitation archive and an exploration archive to provide a variety of search strategies, each archive contains four efficient and easy-implemented search strategies. In addition, online Q-Learning, as well as ε-greedy scheme, are employed as the decision-maker role to learn the knowledge from the past optimization process and determine the search strategy for each individual automatically and intelligently. In numerical experiments, we compare our proposed QVEGE with eight state-of-the-art MAs including the original VEGE on CEC2020 benchmark functions, twelve engineering optimization problems, and wireless sensor networks (WSN) coverage optimization problems. Experimental and statistical results confirm that the proposed QVEGE demonstrates significant enhancements and stands as a strong competitor among existing algorithms. The source code of QVEGE is publicly available at https://github.com/RuiZhong961230/QVEGE.

Vegetation evolution (VEGE) is a newly proposed meta-heuristic algorithm (MA) with excellent exploitation but relatively weak exploration capacity. We thus focus on further balancing the exploitation and the exploration of VEGE well to improve the overall optimization performance. This paper proposes an improved Q-learning based VEGE, and we design an exploitation archive and an exploration archive to provide a variety of search strategies, each archive contains four efficient and easy-implemented search strategies. In addition, online Q-Learning, as well as ε -greedy scheme, are employed as the decision-maker role to learn the knowledge from the past optimization process and determine the search strategy for each individual automatically and intelligently. In numerical experiments, we compare our proposed QVEGE with eight state-of-the-art MAs including the original VEGE on CEC2020 benchmark functions, twelve engineering optimization problems, and wireless sensor networks (WSN) coverage optimization problems. Experimental and statistical results confirm that the proposed QVEGE demonstrates significant enhancements and stands as a strong competitor among existing algorithms. The source code of QVEGE is publicly available at https://github.com/RuiZhong961230/QVEGE. • We propose a novel Q-learning based Vegetation Evolution (QVEGE) for numerical optimization. • Q-learning determines the search operator in the growth period and maturity period of VEGE intelligently. • The performance of QVEGE is investigated on CEC2020 functions, engineering problems, and WSN coverage optimization problems. • Experimental and statistical results verify the efficiency and effectiveness of our proposed QVEGE. [ABSTRACT FROM AUTHOR]

We introduce two new search strategies to further improve the performance of vegetation evolution (VEGE) for solving continuous optimization problems. Specifically, the first strategy, named the dynamic maturity strategy, allows individuals with better fitness to have a higher probability of generating more seed individuals. Here, all individuals will first become allocated to generate a fixed number of seeds, and then the remaining number of allocatable seeds will be distributed competitively according to their fitness. Since VEGE performs poorly in getting rid of local optima, we propose the diverse mutation strategy as the second search operator with several different mutation methods to increase the diversity of seed individuals. In other words, each generated seed individual will randomly choose one of the methods to mutate with a lower probability. To evaluate the performances of the two proposed strategies, we run our proposal (VEGE + two strategies), VEGE, and another seven advanced evolutionary algorithms (EAs) on the CEC2013 benchmark functions and seven popular engineering problems. Finally, we analyze the respective contributions of these two strategies to VEGE. The experimental and statistical results confirmed that our proposal can significantly accelerate convergence and improve the convergence accuracy of the conventional VEGE in most optimization problems. [ABSTRACT FROM AUTHOR]

Fossil pollen and spores are a vital source of information on the geological history of tropical vegetation including reconstructions of vegetation diversity and composition. However, such work relies on a sound taxonomic framework, and this is challenging to achieve because of the large number of pollen and spore morphotypes that are encountered in palynological preparations from tropical sediments. In tropical West Africa, for example, extensive taxonomic work on Cretaceous–Paleogene pollen and spores was undertaken in the later part of the twentieth century, but more recent palynological work has focussed on stratigraphy and basin evolution, and there is a need for additional taxonomic work on the pollen and spores of this region. We have undertaken a descriptive systematic study of pollen and spores (sporomorphs) from 15 sediment samples spanning the Upper Palaeocene–Lower Eocene of south-eastern Nigeria. A palynoflora consisting of 29 spores, two gymnosperm pollen grains, and 138 angiosperm pollen grains is described. Two new spore species are proposed, and one new genus and 18 new species of angiosperm pollen are proposed. The general vegetation type represented by the palynoflora consists of palm-dominated swamps, perhaps with mangroves. The richness of each sample ranges from 29 to 76 sporomorph taxa, and rarefaction analysis suggests an increase in diversity from the Palaeocene to the Eocene in this region. Samples from the Palaeocene Upper Nsukka Formation are dominated by pollen with botanical affinities to the Arecaceae (palms) and Araceae (arums), and this assemblage is very similar to the Palaeocene in the Neotropics. [ABSTRACT FROM AUTHOR]

The study of vegetation evolution is essential for further understanding of biogeographic feedback and ecological restoration. In this paper, a vegetation evolution model based on velocity threshold (scaled by the average flow velocity of the bare bed) was established to simulate the vegetation evolution process in compound channels. In this model, the effect of vegetation on water flow was generalized as equivalent Manning coefficient, and the velocity field was obtained by solving two-dimensional shallow water equations. The model defined that new vegetation was added in areas where the velocity was less than the velocity threshold, and conversely, vegetation was destroyed in areas where the flow velocity exceeded the velocity threshold. The model was used to explore the effect of velocity threshold, initial vegetation coverage, and relative water depth (the ratio of the flow depth in the floodplain to that over main channel) on final vegetation coverage and longitudinal dispersion coefficient (Ke) in compound channels, and compare the difference of vegetation evolution between rectangular channels and compound channels. Results showed that the velocity threshold played a decisive role in vegetation evolution, and the effect of relative water depth and cross section type on vegetation evolution was only reflected when the velocity threshold was small. The longitudinal dispersion coefficient gradually increased with the expansion of vegetation, and tended to a constant value (Kf) when a stable vegetation landscape was reached. As the relative water depth decreased, the longitudinal dispersion coefficient presented an increasing trend. Regular distribution of initial vegetation patches can produce larger longitudinal dispersion coefficient compared to the cases of random distribution in compound and rectangular channels, and the increasing effect was more significant in compound channels. [ABSTRACT FROM AUTHOR]

Palaeolake Flixton, in the eastern Vale of Pickering in northeast Yorkshire, UK, existed as open water during the Lateglacial and early to mid-Holocene, until hydroseral succession and gradual terrestrialisation changed it to an area of fen and basin peatland by the later mid-Holocene. The environs of the lake were occupied by Late Palaeolithic and Mesolithic people over thousands of years and many Early Mesolithic sites, in particular, have been found located along the ancient lake edge, including the paradigm site for the British Early Mesolithic at Star Carr, where occupation occurred over several centuries. We have analysed eleven sediment cores, distributed in most parts of the palaeolake area, for pollen and stratigraphic data with which to reconstruct lake development and vegetation history. These new diagrams augment earlier pollen studies from the western part of the lake, particularly in the Star Carr area and near other major Mesolithic sites around Seamer Carr. Especially informative are a long core from the deepest part of the lake; cores that document the Lateglacial as well as early Holocene times, and evidence for the later Mesolithic that helps to balance the high density of Late Mesolithic sites known from research in the adjacent uplands of the North York Moors. There are many records of charcoal in the deposits but, especially for the earliest examples, it is not always possible to tie them firmly to either human activity or natural causes. Overall, the new and previously existing diagrams provide evidence for the spatial reconstruction of vegetation history across this important wetland system, including (a) for the progression of natural community successions within the wetland and on the surrounding dryland (b) the influence of climate change in bringing about changes in woodland composition and (c) for discussion of the possibility of human manipulation of the vegetation in the Late Upper Palaeolithic, Early and Late Mesolithic. Results show that climate was the main driver of longer-term vegetation change. Centennial-scale, abrupt climate events caused significant vegetation reversals in the Lateglacial Interstadial. The Lateglacial vegetation was very similar throughout the lake hinterland, although some areas supported some scrubby shrub rather than being completely open. Immigration and spread of Holocene woodland taxa comprised the familiar tree succession common in northern England but the timings of the establishment and the abundance of some individual tree types varied considerably around the lake margins because of edaphic factors and the effects of fire, probably of human origin. Woodland successions away from proximity to the lake were similar to those recorded in the wider landscape of northern England and produced a dense, homogenous forest cover occasionally affected by fire. [ABSTRACT FROM AUTHOR]

We introduce two new search strategies to further improve the performance of vegetation evolution (VEGE) for solving continuous optimization problems. Specifically, the first strategy, named the dynamic maturity strategy, allows individuals with better fitness to have a higher probability of generating more seed individuals. Here, all individuals will first become allocated to generate a fixed number of seeds, and then the remaining number of allocatable seeds will be distributed competitively according to their fitness. Since VEGE performs poorly in getting rid of local optima, we propose the diverse mutation strategy as the second search operator with several different mutation methods to increase the diversity of seed individuals. In other words, each generated seed individual will randomly choose one of the methods to mutate with a lower probability. To evaluate the performances of the two proposed strategies, we run our proposal (VEGE + two strategies), VEGE, and another seven advanced evolutionary algorithms (EAs) on the CEC2013 benchmark functions and seven popular engineering problems. Finally, we analyze the respective contributions of these two strategies to VEGE. The experimental and statistical results confirmed that our proposal can significantly accelerate convergence and improve the convergence accuracy of the conventional VEGE in most optimization problems.

In this paper, we have observed that different types of plants in nature can use their own survival mechanisms to adapt to various living environments. A new population-based vegetation evolution (VEGE) algorithm is proposed to solve optimization problems by interactively simulating the growth and maturity periods of plants. In the growth period, individuals explore their local areas and grow in potential directions, while individuals generate many seed individuals and spread them as widely as possible in the maturity period. The main contribution of our proposed VEGE is to balance exploitation and exploration from a novel perspective, which is to perform these two periods in alternation to switch between two different search capabilities. To evaluate the performance of the proposed VEGE, we compare it with three well-known algorithms in the evolutionary computation community: differential evolution, particle swarm optimization, and enhanced fireworks algorithm — and run them on 28 benchmark functions with 2-dimensions (2D), 10D, and 30D with 30 trial runs. The experimental results show that VEGE is efficient and promising in terms of faster convergence speed and higher accuracy. In addition, we further analyze the effects of the composition of VEGE on performance, and some open topics are also given. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Palaeolake Flixton, in the eastern Vale of Pickering in northeast Yorkshire, UK, existed as open water during the Lateglacial and early to mid-Holocene, until hydroseral succession and gradual terrestrialisation changed it to an area of fen and basin peatland by the later mid-Holocene. The environs of the lake were occupied by Late Palaeolithic and Mesolithic people over thousands of years and many Early Mesolithic sites, in particular, have been found located along the ancient lake edge, including the paradigm site for the British Early Mesolithic at Star Carr, where occupation occurred over several centuries. We have analysed eleven sediment cores, distributed in most parts of the palaeolake area, for pollen and stratigraphic data with which to reconstruct lake development and vegetation history. These new diagrams augment earlier pollen studies from the western part of the lake, particularly in the Star Carr area and near other major Mesolithic sites around Seamer Carr. Especially informative are a long core from the deepest part of the lake; cores that document the Lateglacial as well as early Holocene times, and evidence for the later Mesolithic that helps to balance the high density of Late Mesolithic sites known from research in the adjacent uplands of the North York Moors. There are many records of charcoal in the deposits but, especially for the earliest examples, it is not always possible to tie them firmly to either human activity or natural causes. Overall, the new and previously existing diagrams provide evidence for the spatial reconstruction of vegetation history across this important wetland system, including (a) for the progression of natural community successions within the wetland and on the surrounding dryland (b) the influence of climate change in bringing about changes in woodland composition and (c) for discussion of the possibility of human manipulation of the vegetation in the Late Upper Palaeolithic, Early and Late Mesolithic. Results show that climate was the main driver of longer-term vegetation change. Centennial-scale, abrupt climate events caused significant vegetation reversals in the Lateglacial Interstadial. The Lateglacial vegetation was very similar throughout the lake hinterland, although some areas supported some scrubby shrub rather than being completely open. Immigration and spread of Holocene woodland taxa comprised the familiar tree succession common in northern England but the timings of the establishment and the abundance of some individual tree types varied considerably around the lake margins because of edaphic factors and the effects of fire, probably of human origin. Woodland successions away from proximity to the lake were similar to those recorded in the wider landscape of northern England and produced a dense, homogenous forest cover occasionally affected by fire.

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Vegetation evolution was numerically performed based on velocity thresholds. • The vegetation patches interacted with one another, promoting feedbacks and merger. • The evolved vegetation was elongated and covered as much as half the channel area. Computational fluid dynamics was used to study the evolution of small patches of vegetation into a vegetated landscape in a channel. The growth of new vegetation occurred in regions where the flow velocity was reduced below a threshold value defined as a fraction of the channel-average velocity (U 0). Two threshold values, or limiting velocity values (LV), were used: LV = 0.5 and 0.7. Two initial blockage factors (percentage vegetation coverage of the channel) were considered, 3% and 0.3%, chosen to represent cases with and without, respectively, hydrodynamic interaction between the initial patches. The simulation illustrated both positive feedbacks between flow and vegetation, which enhanced vegetation expansion, and negative feedbacks, which led to patch erosion and limited patch growth. The most rapid expansion of the vegetated area occurred during the initial simulation steps, when the flow blockage due to vegetation was small. A higher velocity threshold (higher LV) produced more rapid initial growth and a higher final coverage of vegetation. The patches evolved to one or a few elongated islands extending along the channel. [ABSTRACT FROM AUTHOR]

• 3 Myr pollen record from North China Plain show megacycles variation. • The cool and dry intervals occurred during high Earth orbital eccentricity. • Terrestrial vegetation feedback may have interrupted 41-kyr climatic cyclicity. • Pollen dataset used to produce zonal vegetation maps for East Asia since 3 Ma. Although there are numerous long-term terrestrial climate records based on biological and other indicators spanning the last 3 Myr in Asia, there are few studies on the vegetation evolution on a continental scale. Here we present a long (∼3 Myr) pollen record from core LN-1 from the North China Plain. The record shows that during the interval of 3.0–1.2 Ma, prior to the Mid-Pleistocene transition, the vegetation of the North China Plain was mainly open deciduous broadleaved forest, and that there were five cool and dry phases when conifers and herbs expanded: during 2.7–2.6 Ma, 2.2–2.1 Ma, 1.75–1.85 Ma, 1.5–1.6 Ma, and 1.3–1.4 Ma. Comparison with other pollen records from the East Asian monsoon region reveals a similar series of cool and dry intervals. These extended cool and dry intervals occurred during a period of high Earth orbital eccentricity, and were most likely related to the status of the global ocean carbon reservoir, under eccentricity forcing. We suggest that feedback from the terrestrial vegetation may have interrupted the dominant 41-kyr climatic cyclicity associated with middle and high latitudes of the Northern Hemisphere that had persisted since the Late Pliocene. After 1.2 Ma, the vegetation of the North China Plain changed to steppe and shrub steppe, while at the same time grassland expansion and forest recession occurred in northern China. The associated global cooling led to decreases in ocean temperatures, land-sea exchanges, and monsoon precipitation, which together drove the aridification of the Asian interior. We combined our data with eight published pollen records, and the zonal vegetation maps for East Asia since 3 Ma were generated. [ABSTRACT FROM AUTHOR]

Reconstructing the vegetation history of southwest China since the Last Glacial Maximum is crucial for understanding the evolution of the Indian summer monsoon. In this study, we present a high-resolution palynological investigation from a 5 m core from the Ganchi peatland (southwest margin of the Sichuan Basin, southwest China) in order to reconstruct regional vegetation and climate over the last 25 kyrs. The succession, from bottom to top, comprises lake, wetland, and peat deposits, and wetland/aquatic pollen types are found to be a sensitive indicator of palaeoenvironmental change. Deciduous broad leaf forests dominated by Betula were present between 25-18 cal kyrs BP, suggesting a cold and dry climate during the Last Glacial Maximum. After 18 cal kyrs BP, temperature and summer insolation increased gradually, marking the Lateglacial transition. Thermophilous and hygrophilous species expanded between 11-8 cal kyrs BP, indicating a progressively warmer and wetter climate. From 8-4 cal kyrs BP, evergreen forests developed, while Tsuga reached its maxim abundance, implying a warm and humid climate coincided with the mid-Holocene climatic optimum. Results indicate that residual ice sheets may have impeded the northward shift of the Intertropical Convergence Zone, resulting in peak Holocene warmth lagging behind peak summer insolation forcing. Vegetation change was primarily controlled by climate, with no obvious evidence of anthropogenic disturbance until the last 1 cal kyrs BP. Our study shows that vegetation and climate in the southwest margin of the Sichuan Basin were controlled by summer insolation and ice sheet dynamics, and also influenced by sea surface temperature in the Indian Ocean. • High-resolution pollen records revealed vegetation and climate history since 25 cal kyrs BP • Variations in proxies were highly correlated with depositional processes • Paleovegetation records suggest that the Holocene climate optimum occurred during 8-4 cal kyrs BP • The most conspicuous landscape transformation caused by human impact in the Sichuan Province began at ∼1 cal kyrs BP [ABSTRACT FROM AUTHOR]

The frequency and amplitude of water level fluctuations were major driving forces for wetland vegetation evolution in the Poyang Lake Deltas. This study examined changes in wetland vegetation evolution of two deltas, namely Ganjiang Main-branch Delta wetland (GMD) and Ganjiang Southern-branch Delta wetland (GSD), in autumns from 1973 to 2009. Wetland vegetation evolution monitoring using Landsat remotely sensed imageries was related to changes in hydrology stemming including the annual peak, lowest water levels and number of flooded days at four characteristic water levels (10, 13, 15 and 17 m) from natural climatic variations. Results showed that the annual peak water level of GMD (Xingzi station) decreased by 5.78 m and the annual lowest water level decreased by 2.27 m; while the annual peak water level of GSD (Tangyin station) decreased by 6.41 m and the annual lowest water level decreased by 2.53 m. The number of flooded days at water levels 15 and 17 m indicated a consistent trend while flooded days at water levels 10 and 13 m were significantly different. Vegetation coverage of both deltas showed trends of increasing and expanded fan-shaped towards the middle of the lake area. The annual peak and lowest water levels had negative correlation with the vegetation coverage areas for both deltas. The flooded days at water level 13 m had the greatest effect on the vegetation coverage area at GMD; while the flooded days at water level 17 m had the greatest effect on the vegetation coverage area at GSD. [ABSTRACT FROM AUTHOR]

Pollen analysis of a 236-cm-long core at Daping Swamp, a subalpine swamp in the western Nanling Mountains, provided a history of vegetation evolution that was related to climate changes in the last 15,400 years. Generally, pollen data revealed a subtropical climate in the past 15,400 years. In the last deglacial period (15,400–10,900 cal yr BP), the study region was characterized by evergreen and deciduous broadleaved forests. A marked warm and wet period from 15,400 to 13,200 cal yr BP, which was characterized by high frequencies of arboreal pollen, corresponded to the Bølling–Allerød event. Significant shrinkage of evergreen–deciduous broadleaved forests and expansion of grassland from 13,200 to 10,900 cal yr BP suggested evidently cool and dry conditions that were the reflection of the Younger Dryas event. In the early Holocene (10,900–8200 cal yr BP), the glacier boundary effect might cause less warm and humid conditions relative to the middle Holocene. From 8200 to 4600 cal yr BP, pollen data reflected a marked expansion of evergreen and deciduous broadleaved forests and shrinkage of grassland, suggesting the thermal maximum that could be considered as the Holocene Optimum. From 4600 to 1500 cal yr BP, grassland exhibited expansion. Between 1500 and 600 cal yr BP, the evergreen and deciduous broadleaved forests expanded, whereas the grassland shrunk, implying a short wetter and warmer interval. After 600 cal yr BP, the grassland displayed expansion again. Broad regional correlation reflected that multiple factors including the summer monsoon, variation of sea level, ocean sea surface temperature (SST), and solar insolation may have played a role in climate changes that influenced vegetation evolution in the study area. Our results also reflected that in South China, the subalpine regions exhibited a different climate variation from that of regions with low latitude and elevation. [ABSTRACT FROM AUTHOR]

Copyright of Ingénierie des Systèmes d'Information is the property of International Information & Engineering Technology Association (IIETA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

River ecological functioning can be conceptualized according to a four-dimensional framework, based on the responses of aquatic and riparian communities to hydrogeomorphic constraints along the longitudinal, transverse, vertical and temporal dimensions of rivers. Contemporary riparian vegetation responds to river dynamics at ecological timescales, but riparian vegetation, in one form or another, has existed on Earth since at least the Middle Ordovician ( c. 450 Ma) and has been a significant controlling factor on river geomorphology since the Late Silurian ( c. 420 Ma). On such evolutionary timescales, plant adaptations to the fluvial environment and the subsequent effects of these adaptations on fluvial sediment and landform dynamics resulted in the emergence, from the Silurian to the Carboniferous, of a variety of contrasted fluvial biogeomorphic types where water flow, morphodynamics and vegetation interacted to different degrees. Here we identify several of these types and describe the consequences for biogeomorphic structure and stability (i.e. resistance and resilience), along the four river dimensions, of feedbacks between riparian plants and hydrogeomorphic processes on contrasting ecological and evolutionary timescales. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In order to study vegetation evolution and environmental change during 3.15-0.67 Ma, a total of 608 pollen samples with an average time resolution of 4 ka has been analyzed from ODP Site 1145 (water depth 3175 m), northern South China Sea. The deep-sea sediments (213.62-91.9 m) cover from 3.15 to 0.67 Ma based on micropaleonotological stratigraphy. The characteristic features of the pollen diagram include that, pollen influx rises twice obviously around 2.58 Ma and during 2.0-1.8 Ma, in response to global climatic cooling and winter monsoon enhancement. Before 2.58 Ma, tropical and subtropical vegetation, mainly evergreen Quercus (E) and Altingia, predominated around northern SCS with much more tropical montane conifers and ferns relatively. From 2.58 Ma, temperate vegetation increased obviously, implying climatic cooling and winter monsoon enhancement. Spectral analysis shows that percentage variation in tropical and subtropical taxa has a strong 20 ka procession cycle probably due to the summer monsoon; while pollen influx has 100, 41 and 19 ka cycles, indicating the sea level and winter monsoon change response to the ice-sheet variations. [ABSTRACT FROM AUTHOR]

Based on deep-sea pollen results (512-76 m) from ODP Site 1143 in the southern South China Sea (SCS), the climate and vegetation evolution sequence on the surrounding islands and the exposed continental shelf are discussed. The pollen records show that the pollen influx was quite low before 8.15 Ma and increased dramatically afterwards. The influx changes can be ascribed, on one side, to tectonics deformations around the southern SCS resulting in rapid uplift of islands and subsequent increase of the sediment rates and pollen influx and on the other side to climate cooling and monsoon enhancement. Around 2.63 Ma was another obvious boundary, the increasing of pollen and spores influx since this time was mainly related to global climate cooling. Spectrum analysis of pollen influx values shows that 2 Ma, 0.67 Ma, and 0.19-0.17 Ma cycles existed during 12-3.0 Ma, while 0.1 Ma and 46.9 ka cycles existed during 3.0-2.0 Ma. [ABSTRACT FROM AUTHOR]

The 26 plots including natural forestland, secondary forestland, shrub-grassland, sloping cropland, artificial forest and abandoned field, were selected to discuss the impact of land cover on the soil characteristics in the three karst districts of Chongqing. The results showed that: (1) After the vegetation turned into secondary vegetation or artificial vegetation, or reclamation, soil physical properties would be degraded. In the surface-layer soil of sloping cropland, the contents of > 2 mm water-stable aggregates decreased obviously with apparent sandification. (2) The contents of soil organic matter and total nitrogen are controlled completely by vegetation type and land use intensity. The increasing trend is rather slow in the early days when over-reclamation is stopped and the land is converted to forest and pasture. (3) Herbaceous species increase and woody plants species decrease with the increase of land use intensity, therefore, the soil seed banks degrade more seriously. (4) The soil degradation index has been set up to describe the relative soil degradation degree under the conditions of different vegetation types. (5) Land cover has a significant effect on karst soil characteristics, land degradation in the karst ecosystem is essentially characterized by the different degradation of soil functions that serve as water banks, nutrient banks and soil seed banks. [ABSTRACT FROM AUTHOR]

The Late Miocene and Pliocene are the key periods for understanding the origin and development of the present Asian monsoon circulations and ecologic environments. Here we present a pollen record from Chaona Red Clay section located in the central Loess Plateau in attempt to establish the histories of vegetation and associated climate changes between 8.10 and 2.60 Ma. Our results show that Gramineae-dominated woodland-grasslands developed in this region with Cedrus- and Pinus-characterized montane coniferous forests distributing in higher elevations from 8.10 to 6.73 Ma, probably suggesting a semi-humid climate in a warm-temperate zone. A subsequent expansion of Ulmus-dominated deciduous forests and a synchronous increase of Gramineae-dominated grassland reflect a warmer and more humid climate between 6.73 and 5.67 Ma. The vegetation changed to an Artemisia. and Gramineae-characterized steppe in lower elevations and to a coniferous forest in higher elevations from 5.67 to 3.71 Ma, implying probably a warm and semiarid climate in lowland and hill, and a colder and moister climate in mountain. During this period, a considerable warmer and more humid climate occurred between 4.61 and 4.07 Ma as indicated by pollen assemblages. The period between 3.71 and 2.58 Ma was characterized by the disappearance of Cedrus and Tsuga and also by an abrupt expansion of Cupressaceae, reflecting a drastic enhancement of monsoon-related climatic seasonality. [ABSTRACT FROM AUTHOR]

Sporopollen record in the Laojunmiao Section at Yumen in the Hexi Corridor foreland depression at the northern margin of the Tibetan Plateau revealed that during the period of 13.0–11.15 Ma the ecological environment of the Jiuxi Basin is characterized by steppe vegetation and a semi-moist climate. During 11.16–8.60 Ma prevailed forests of cypress and a still warmer, moister climate; steppe vegetation and dry climate began probably at about 8.6 Ma. Although aridification had been relaxed time and again during 8.40–6.93 Ma (forest-steppe, warm-semi-moist), 6.64–5.67 Ma (open-forest and steppe, warmer-semi-moist) and 5.42–4.96 Ma (steppe, semi-arid), the climate in the region became drier and drier in response to the fre-quent occurrence of aridity during 6.93–6.64 Ma (steppe, semi-arid), 5.67–5.42 Ma (de-sert-steppe, arid), 3.66–3.30 Ma (desert-steppe, arid) and 2.56–2.21 Ma (desert, arid). Perhaps the important findings of our study are the notable expansion of drought-enduring plants during 3.66–3.30 Ma and about 2.56 Ma and the replacement of vegetation by vast arid desert. [ABSTRACT FROM AUTHOR]

In order to study vegetation evolution and environmental change since the Last Glacial Maximum (LGM), a total of 180 pollen samples with an average time resolution of 150 years were analyzed on the top parts (0–31 m, 0–27 kaBP) of deep sea sediments from ODP Site 1144 (20°3.18′N, 1170°25.14′E), northeastern SCS. The characteristic features of pollen diagram include that pine dominates in the interglacial, and herb pollen dominates with 8 good deal of tropical-subtropical pollen in the last glacial, and from 18 kaBP the tropical-subtropical pollen influx rose abruptly, while the herbaceous pollen influx and percentage dropped quickly, indicating that climate turned warmer and more humid, and more tropical-subtropical vegetation grew on the mainland and the emerging continental shelf, while the grassland on the shelf diminished. A detailed comparison shows an earlier change of pollen assemblages at the glacial-interglacial transition between MIS6 and 5 (Termination II) than the ice volume chance Indicated by the oxygen isotope record, implying that mid-low latitude climate warming preceded ice sheet retreat. Millennial-scale climatic fluctuations of vegetation change in pollen record are also discussed. [ABSTRACT FROM AUTHOR]

A vegetation cover increase has been identified at global scales using satellite images and vegetation indices. This fact is usually explained by global climatic change processes such as CO2 and temperature increases. Nevertheless, although these causes can be important, the role of socioeconomic transformations must be considered in some places, since in several areas of Northern Hemisphere an important change in management practices has been detected. Rural depopulation and land abandonment have reactivated the natural vegetation regeneration processes. This work analyses the vegetation evolution in the central Spanish Pyrenees from 1982 to 2000. The analysis has been done by using calibrated-NDVI temporal series from NOAA-AVHRR images. A positive and significant trend in NDVI data has been identified from 1982 to 2000 coinciding with a temperature increase in the study area. However, the spatial differences in magnitude and the sign of NDVI trends are significant. The role of land management changes in the 20th century is considered as a hypothesis to explain the spatial differences in NDVI trends. The role of land-cover and human land-uses on this process has been analyzed. The highest increment of NDVI is detected in lands affected by abandonment and human extensification. The importance of management changes in vegetation growth is discussed, and we indicate that although climate has great importance in vegetal evolution, land-management changes can not be neglected in our study area. [ABSTRACT FROM AUTHOR]

• Four phased sea-level rise were observed during ~7.9–~7.1 cal ka BP. • The abrupt cooling event from 7460 to 7230 cal a BP may have been a global event. • Broadleaved tree was high suggesting a strong monsoon during ~8.2–~7.0 cal ka BP. To understand vegetation dynamics and their response to climate changes and sea-level rise (SLR) on the northern coast of the Bohai Sea during a marine transgression period (8.2–7.0 cal ka BP), we obtained two sedimentary cores (HG01 and HG02) with high-resolution accelerator mass spectrometry carbon-14 (14C) data from the coastal plain of Bohai Bay in northeastern China. A general warming and wetting trend from 8190 to 7920 cal a BP was indicated by the greater abundance of deciduous broadleaved forest, which showed that the Asian summer monsoon was stronger over this period. The abundance of deciduous broadleaved trees was relatively high, which revealed that the climate was relatively warm and wet and that the Asian summer monsoon was strong, during the periods of 7920–7690 cal a BP and 7230–7020 cal a BP. Broadleaved tree abundance decreased over the intervening period—from 7610 to 7230 cal a BP—suggesting a declining monsoon, and relatively cool, dry climate. The abrupt cooling event from 7460 to 7230 cal a BP may have been a global event, closely related to the decrease in solar activity and rapid SLR before 7460 cal a BP. The results also showed that the large number of halophytes mainly Chenopodiaceae, sharply increased at times, mirroring four SLR fluctuation periods: 7940–7860 cal BP, 7760–7700 cal BP, 7560–7460 cal BP, and 7230–7130 cal BP. SLR in Bohai Bay occurred during warm and wet climate periods, and the phased SLR observed during ~7.9–~7.1 cal ka BP may have been the local manifestation of a global event. [ABSTRACT FROM AUTHOR]

• A conceptual model is proposed to study the evolution of vegetation patches. • The relationship between final coverage and initial vegetation patches is revealed. • The longitudinal dispersion is usually enhanced during the vegetation evolution. • The effects of critical bed shear stress on the vegetated landscape is explored. Hydrodynamic conditions are important controlling factors in the evolution of vegetation and ecosystems, especially aquatic ecosystems. This study established a conceptual vegetation evolution model to explore the succession law of vegetation patches in the effective area of a channel, including the evolution of vegetation coverage (C e) and the corresponding longitudinal dispersion coefficient (K e). 2D shallow-water equations were implemented to calculate flow variables, and the equivalent Manning coefficient was used to reflect the effects caused by vegetation patches. New vegetation emerged in regions where the bed shear stress is lower than the critical bed shear stress, whereas the original vegetation was removed in regions where the bed shear stress is higher than the critical value. Two typical cross-sections and two initial C e were considered to better understand the succession trend of vegetation patches under different external conditions. The findings showed that C e and K e increased to a constant value with increasing simulation duration, whereas a higher critical bed shear stress, defined by the threshold value (TV), was linked to a higher final vegetation coverage (C f) and final longitudinal dispersion coefficient (K f). Furthermore, different initial vegetation distributions, including coverage and position, caused little effect on the C f in the rectangular channel, but the C f in the parabolic channel was linearly affected by the averaged bed shear stress at the initial patches. The maximum K f in both channels occurred with regularly distributed initial patches on one side of the bank. The vegetation patches in all scenarios evolved from block-shaped to strip-shaped and finally formed a stable vegetated landscape. This conceptual vegetation evolution model will improve our understanding of the influence of hydrodynamic conditions on the vegetation evolution in aquatic ecosystems. [ABSTRACT FROM AUTHOR]

High-resolution pollen and charcoal records from Dianchi in central Yunnan Province, southwestern China are presented in this study and reveal variations in vegetation, fire, lake environments, and climate over the last 20,000 years (20 ka). The results show that the climate during the period 20.0–18.0 ka was relatively cold, and rainfall in winter and early spring was relatively lower than the present, which belongs to the Last Glacial Maximum (LGM). After 18.0 ka, the temperature increased gradually, indicating the onset of deglacial warming in central Yunnan Province, though the mean annual temperature before 10.8 ka was still at least 1.5 °C lower than today. The climate began to obviously warm from ∼10.8 ka and was at least 2 °C higher than today and relatively humid between 10.0 and 5.4 ka, denoting the early-Holocene Thermal Maximum. A major vegetation change around Dianchi occurred at ∼5.4 ka and was most likely caused by the climate cooling and drying with no obvious evidence for cultivation activities except for some possible evidence of human fire use or selective deforestation from the pollen assemblage. Significant cultivation activities in Yunnan Province indicated by the first obvious increases in Poaceae (>40 μm) and Poaceae (25–40 μm) pollen percentages began at ∼2.4 ka. In central Yunnan Province, there was a continuous deglacial warming that occurred between 18.0 and 12.5 ka without marked interruption during the interval of Heinrich Event 1 (H1). Additionally, the Holocene Thermal Maximum occurred in the early Holocene. The results from this study are different from the western region of southwestern China where the paleoclimate studies have clearly detected the H1, the B/A, and the YD events, and revealed a mid-Holocene climatic optimum. • High-resolution pollen and charcoal records reveal vegetation and climate history since 20.0 ka. • Significant cultivation activities in Yunnan Province began at ∼2.4 ka. • A continuous deglacial warming was not markedly interrupted during the time interval of H1 in central Yunnan. • There are discrepancies between the climate models inthe eastern and western regions of southwestern China. [ABSTRACT FROM AUTHOR]

The geological transitional period from the Marine Isotope Stage (MIS) 5 to 4 during the Quaternary period is a multidimensional change involving monsoon and precipitation variation, vegetation dynamics, and environmental evolution. The first loess layer (L1) and the first paleosol layer (S1) in the Chines Loess Plateau provide excellent high-resolution terrestrial sediment record for this transition. In this work, grain size (GS), CaCO3 content, magnetic susceptibility (MS), and pollen composition were measured at intervals of 2-cm in two representative L1/S1 profiles in the southern Chinese Loess Plateau to reconstruct records of climatic and vegetative changes during this transition. Our results showed that, in general, the paleo-vegetation type was forest-steppe, with Pinus being the commonest tree, and Chenopodiaceae and Artemisia being common herbs in the study area. The topography had a significant impact on the distribution of paleo-vegetation. The increase of coarse particles, the decrease of magnetic susceptibility, and the rising percentage of Gramineae, Artemisia and Chenopodiaceae pollen, all indicated that the paleoclimate became cooler and drier over the transitional period. Besides, we identified a cool event at about 76.8 ka B.P. as revealed by grain-size curves, and in response to this event, the vegetation changed significantly but lagged several hundred years behind the grain size record. This study confirmed the cooling and drying tendency during the MIS 5 to 4 transition phase in the southern margin of the Chinese Loess Plateau. These findings shed light on the climatic change on vegetation evolution during the MIS 5 to 4 transition period. [ABSTRACT FROM AUTHOR]

Based on the high resolution record of fossil pollen data from a 190 cm sediment profile collected in a Betula microphylla -dominated wetland of Ebinur Lake in Xinjiang, we aimed to reveal the changes of vegetation and environment in this wetland over the past 3900 years. Results showed that, in the period between 3420 cal. aBP and 3940 cal. aBP, this area was a desert landscape dominated by plants from Chenopodiaceae and Artemisia . During the period of 2830-3420 cal. aBP, this area became a desert steppe dominated by Thelypteris palustris , surrounded by desert plants mainly composed of Chenopodiaceae and Artemisia . In the period between 2640 and 2830 cal. aBP, Typha pollen increased and occupied a dominant position. The area thus became a typical desert intrazonal wetland mainly composed of Typha . In the period between 1200 and 2640 cal. aBP, Phragmites australis began to grow vigorously and became the dominant species. In the period between 660 and 1200 cal. aBP, the population of Betula expanded rapidly, and P. australis plants continued to grow. During the period of 340-660 cal. aBP, the population of B. microphylla became the dominant species, and the abundance of P. australis decreased. However, there was still some P. australis wetlands in the area. Over the past 340 years, as the area of wetlands decreased and the surface water gradually declined, B. microphylla had grown on swampy meadow soils with suitable moisture conditions. In the past 200 years especially, the sharp increases of Chenopodiaceae pollen in palynological assemblage was closely related to the enhancement of human activities and climate change, resulting in the degradation of wetlands and endangerment of B. microphylla . Therefore, it is necessary to strengthen the protection of wetlands and endangered species in this area.