Mediterranean landscapes and plant communities relationship

Climate change induces changes in plant communities according to species' climatic requirements. These changes can be assessed by community climatic disequilibrium (CD), which corresponds to the difference between the climate inferred from the climatic requirements of the species in a community (community‐inferred climate, CIC) and the local observed climate. We assessed changes in CIC and CD during a long‐term climatic manipulation (warming and drought treatments), embedded within the ongoing trends of climate change, in a Mediterranean shrubland (NE Iberian Peninsula) during 1999–2014. We used plant censuses, species distribution and climate layers since 1979 to create a multivariate environmental space where CIC and CD trends were estimated for 1999–2014. CD consistently decreased, concomitant with an overall climate change‐derived increase in aridity (higher temperature and lower precipitation). CIC significantly changed during 1999–2014, reflecting the reshuffling of the community composition due to an increase in the abundance of species distributed in warmer, drier and more seasonal localities. Overall, treatments simulating greater climate change did not accelerate the decrease in CD. However, a trend of steeper diminution of CD was observed under warming treatment. In turn, under drought treatment the species less adapted to seasonality and aridity became less abundant. This community tracking of climate did not follow yearly climatic variability; instead, it was detected by the CD trend at the decadal scale. Synthesis. The procedure developed to measure CD reflects demographic behaviours, thus providing a reliable method to assess the impact of climate change on species and communities. The study demonstrates the current, rapid tracking of Mediterranean woody plant communities to climate change. This tracking results from changes in the abundance of species according to their climatic requirements, inferred from their distribution. However, inertia in demographic processes implies that plant communities do not immediately fit current climate change at local level, as supported by the minor effect of experimentally accentuated climate change.

A factorial field experiment was used to assess the influence of soil-disturber mammals in the structure of a 9-year-old Mediterranean annual plant community subjected to different sheep grazing and irrigation regimes. We estimated the disturbance rate (mound building activity) by Mediterranean voles, their effects on vegetation and the mechanisms of these effects during a period of vole outbreak. The effects on vegetation were analysed at the levels of species, functional groups and plant community. Disturbance rate was high and voles can disturb the entire soil surface once every four or five years. The availability of certain trophic resources (perennial plants) appeared to drive vole expansion in the experimental plots and it was independent of the irrigation and grazing treatments. Mound building activities largely affected vegetation but conserved plot differences. Total vegetation cover, absolute cover of all functional groups, mean vegetation height and species richness were less on mounds than on undisturbed ground. These effects did not change the relative abundance of annuals, perennials, grasses and forbs. Only the relative abundance of small-seeded species decreased on mounds. As the proportion of these seeds was similar in both types of patches, we suggest that small-seeded species had more difficulties for germinating or emerging when they are buried during mound formation. Irrigation and sheep grazing promoted large changes in the vegetation parameters but these effects were, in general, similar on mounds and undisturbed ground. Our results show that the availability of germinable seeds may be the major limitation for mound revegetation, probably due to the scarcity of seeds existing at the depths from which soils are excavated. Our results also suggested a resource limitation on mounds. The results provide additional evidence that soil disturbances by small herbivore mammals exert relevant ecological effects on abandoned Mediterranean croplands. We discuss the ecological implications of vole mound-building activities for plant succession, plant species conservation and forage resource availability for livestock.

PDF HTML阅读 XML下载 导出引用 引用提醒 优势种去除对崇明东滩盐沼湿地生态系统的影响 DOI: 10.5846/stxb201701030023 作者: 作者单位: 华东师范大学生命科学学院,华东师范大学生命科学学院,华东师范大学生命科学学院,华东师范大学生命科学学院,华东师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31100317）；上海市科委科技创新行动计划（14DZ1206003） Effects of dominant species removal on salt marsh ecosystem in Chongming Dongtan Author: Affiliation: School of Life Science,East China Normal University,School of Life Science,East China Normal University,School of Life Science,East China Normal University,School of Life Science,East China Normal University,School of Life Science,East China Normal University Fund Project: National Natural Science Foundation of China (NSFC);Innovation action plan of Science and Technology Commission of Shanghai Municipality 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:盐沼生态系统环境梯度明显，物种组成较简单，是研究生物多样性与生态系统功能关系的理想对象。本研究以崇明东滩盐沼湿地为研究区域，研究优势种去除对植物群落结构以及底栖动物群落的影响。结果表明：（1）去除处理仅对植物群落分株密度有极显著效应（P<0.01）。去除组和对照组物种组成差异随时间增加而减小，处理效应逐渐减弱。（2）去除组底栖动物密度均低于对照组，但差异不显著。（3）盐沼植物群落特征与底栖动物群落有密切关系，植物密度、冠层高度与底栖动物密度相关性极显著。去除优势种后，植物群落分株密度升高，群落内剩余物种占比有所上升，次优势种对群落的补偿效应具有较大贡献；而底栖动物群落密度下降，其生物量和多样性指数的变化趋势与密度并不一致。上述结果表明生物多样性变化影响了盐沼湿地生态系统植物群落和底栖动物群落结构，进而可能影响物质循环和能量流动过程。 Abstract:The salt marsh ecosystem is considered ideal for studying the biodiversity-ecosystem functioning relationship(BEF) because of its steep environmental gradients and relatively few plant species. The salt marsh ecosystem is one of the ecosystems most affected by anthropogenic activities, which has drawn our attention to the need to protect and restore it intensively. The current research studies on BEF are mostly focused on grasslands ecosystems rather than salt marshes. The understanding of how the removal of specific species or functional groups would influence the structure and functioning of salt marsh ecosystems is still lacking. Therefore, this study, which was performed at Chongming Dongtan in the Yangtze estuary, examined the effects of dominant species removal on plant community structure and macrobenthic invertebrate communities. We also analyzed the relationship between plant community attributes and macrobenthic invertebrate communities using linear regression. The aim of the study was to provide a scientific basis for wetland restoration. The major findings of this study are as follows (1) Community type, season and their interaction had significant effects on the ramet density and canopy height of manipulated plant communities(P<0.01), whereas the removal treatment had significant effects on the ramet density only(P<0.01). Ramet density in species removal treatment was higher than that in the control treatment was, but the effect was not significant. The differences in species composition among the different plant communities decreased with time, indicating that the effects of species removal treatment weakened gradually. The probable underlying mechanism was that the system recovered from the initial disturbance and became more similar to the intact communities. There were no significant differences in ramet density, canopy height and belowground biomass of all the different plant communities between the control and species removal treatments. This might be due to the species compensatory effects and the recovery ability of dominant species since only the aboveground parts of the dominant plants were removed. (2) Community type and the season significantly affected the density and Shannon-Weiner diversity index of the macrobenthic invertebrate communities(P<0.01). Community type and interaction between the season and community type had significant effects on the biomass of macrobenthic invertebrates(P<0.01). The density of macrobenthic invertebrates in the species removal treatment was lower than that in control treatment, but the effects were not significant. The highest density, biomass and Shannon-Weiner diversity index of the macrobenthic invertebrates were observed in the Spartina alterniflora-Scirpus mariqueter community. This was mainly caused by differences in environmental factors and plant species attributes of the inhabiting communities. (3) There was a close relationship between salt marsh vegetation and benthic community. The density of macrobenthic invertebrates was positively and negatively correlated with shoot density and canopy height of the inhabiting plant communities, respectively (all P<0.01). After removal of the dominant species, ramet density of the plant communities and proportion of remaining species increased, while the subdominant species contributed greatly to the compensatory effect. The density of macrobenthic invertebrates decreased, but the pattern of biomass and diversity index change differed from that of the density, probably because of the influence of other environment factors. The above results indicated that the biodiversity change could affect the structure of plant and macrobenthic invertebrate communities to different degrees, which may then alter the processes of the biogeochemical cycle and energy flow. During our study, the removal effects were relatively weak in the intertidal zone of Chongming Dongtan, and they diminished with time. Therefore, the simple removal of dominant species may not be sufficient to restore the ecosystem functions of salt marshes, and further management measures should be used to maintain the long-term effects of habitat modification. 参考文献 相似文献 引证文献

The large-scale (1 : 10 000) vegetation map of the “Kulikovo Pole” museum-reserve (Tula Region) is presented. The “Kulikovo Pole” museum-reserve is situated in the northeastern part of the Central Russian Upland within the forest-steppe zone (Isachenko, Lavrenko, 1980). The study area has undergone long-term agricultural use, so the arable land is accounted for up to 80 % of the area until recently. The natural vegetation — forests, meadows, steppes — is concentrated in the small unsuitable areas, mainly in river valleys and ravines. In recent decades, some reduction in the area of arable land had happened and, as a result, a wide spread of fallow land was recorded (Burova, 2018). The main attention was paid to mapping of old-field vegetation, which makes it possible to show the diversity of serial plant communities, their successional status (the successional status of fallow vegetation communities was determined based on their biomorphic and phytosociological spectra (Golovina, 2015)) and direction of change. Another goal was to reflect the set and patterns of spatial distribution of natural vegetation in ravines and river valleys, where different types of plant communities replace each other over a short distance. The vegetation map is based on the author field observations and a set of relevés (about 600). The vegetation was visually interpreted using GeoEye satellite image. A detailed field survey was carried out in 2012–2015. The plant community classification was done using the dominant (ecological-phytocoenotic) approach. The map legend consists of 146 basic units, the main mapping units of homogeneous vegetation were associations, community types and their variants. For heterogeneous vegetation, the combinations succession series (in case of old-field vegetation and suchlike) and ecological series (in case of hygrophytic vegetation of the ravine bottoms) were used as mapping units. The combinations of plant communities on the slopes of ravines and river valleys are the most complex. In this case, the basic legend number shows all plant communities characteristic of a given relief element, for example, for slopes of a certain exposure. After the name of plant community, its counting number is indicated in parentheses. Naturally, the representation of habitats and plant communities is different; a complete combination is not always noted. Specific sets of plant communities are given under extensions (marked with a letter indices) of the basic legend numbers in the form of counting numbers of communities connected by a “+” sign. Combinations of plant communities of certain succession series are considered as mapping unit “succession series”; obviously, the successions have anthropogenic origin. The most difficult to map are the series of old-field vegetation. In general, at the time period of the survey, the restoration of vegetation on fallow lands was proceeding from weed and ruderal annual and biennial plants (Erigeron canadensis, Carduus acanthoides, Lactucaserriola, etc.) communities via Elytrigia repens communities and perennial dicotyledons (ruderal and apophytes) communities to Poa angustifolia communities. Apparently, this series can be considered as generalized demutation series. In the legend, using numbers, it is divided into private series. The latter are distinguished based on the composition of perennial dicotyledons communities. Under the basic legend numbers, the private series of communities are usually given; the counting number is indicated in parentheses. Specific sets of plant communities are given under extensions (marked with a letter indices) of the basic legend numbers in the form of communities counting numbers, connected by mathematical symbols “=”, “&gt;” and “&lt;”, showing the areal ratio of communities. In the sequence of letter indices from “a” onwards, the advancement of communities and the area occupied by more advanced communities increases. The ratio of areas of the plant communities’ main types is shown in Table 1. The cultivated fields cover 44.1 % and fallow lands — 23.0 %, which together occupy almost 70 % of the area, which is natural in the conditions of the agricultural landscape. Meadows, mainly steppe meadows, account for 14.6 % of the area, forests — 3.5 %. The area covered of other types of plant communities is 0.2–1.1 % of the total area of the museum-reserve.

Since the Industrial Revolution, the rapid global population and economic expansion have had tremendous impacts on biodiversity across spatial scales, especially for islands. While changes in species richness are easily inferred, the impact of human activity on the underlying community assembly processes has been difficult to ascertain because of lack of long‐term community data. Here, we document how the manifestations of plant community assembly have changed over time and space in a Mediterranean archipelago, using a long‐term dataset of plant species composition on 16 Tuscan islands sampled across two centuries. The community structure of Mediterranean island plant communities was assessed by integrating species' trait and evolutionary distances. We found that, with increasing island area, the functional and phylogenetic structure of plant communities shifted from clustered early (1830–1950) to overdispersed more recently (1951–2015). On large islands, extirpated species were generally more phylogenetically or functionally similar to remaining residents than expected by chance, while colonists were generally more distantly related to residents. The extinction of similar species and the colonization of dissimilar species drove plant communities towards overdispersion. Synthesis. We provide evidence that plant community assembly on islands has dramatically changed following increased human impacts during the last two centuries, and that this change is shaped by the scale dependency of species extinctions and colonizations. Our results reveal accelerated species replacements of closely related residents by distant colonists on large islands over time, reflecting changes in community assembly and which could alter the functioning of island ecosystems in the future.

Abstract. Addi A, Soromessa T, Bareke T. 2020. Plant diversity and community analysis of Gesha and Sayilem Forest in Kaffa Zone, southwestern Ethiopia. Biodiversitas 21: 2878-2888. The study was conducted at Gesha and Sayilem districts of the Kaffa Zone with the objective of identifying the floristic compositions, plant community types, and associated environmental factors of the forest. Stratified random sampling technique was used. A total of 90 plots were used to collect vegetation data. The plant community classification was performed using agglomerative Hierarchical cluster analysis Ward’s linkage method was applied in R-software. Species diversity and evenness were evaluated using the Shannon diversity and evenness indices respectively. The study revealed that the study area composed of 300 species that belong to 239 genera in 96 families. Asteraceae was the most abundant family followed by Fabaceae, Acanthaceae, Poaceae, Rubiaceae, and Euphorbiaceae accounting 37%, 15%, 14%, 13%, 12%, and 9% respectively. Five plant community types were identified and these were Ilex mitis-Syzygium guineense, Pouteria adolfi-friedericii-Schefflera abyssinica, Millettia ferruginea-Sapium ellipticum, Arundinaria alpina and Schefflera volkensii-Masea-lanceolata community types. Among the community types, Pouteria adolfi-friedericii-Syzygium guineense community was the most diverse whereas Arundinaria alpina community was the least diverse community. Canonical Correspondence of vegetation data analysis indicated that altitude, disturbance, slope, phosphorus, and the electrical conductivity were the environmental factors that significantly influence the plant communities. The high dependency of local communities on the forest resources is affecting the plant biodiversity. Thus, conservation of the forest through the introduction of sustainable forest management interventions including participatory forest management seems an appropriate action.

Fire is a fundamental ecological process with a long history on Earth, determining the distribution of vegetation formations across the globe. Fire, however, does not only affect the vegetation but also the soil on which vegetation grows, creating a post-fire environment that differs significantly in terms of soil chemical and physical properties from the pre-fire environment. The duration of these alterations remains largely unknown and depends both on the vegetation condition and the fire characteristics. In the current study, we investigate the effect of fire on some chemical and physical properties 11 years after the event in four plant communities. Two of them constitute typical Mediterranean fire-prone plant communities, dominated by sclerophyllous Mediterranean shrubs, such as Quercus coccifera and Q. ilex, while the other two are not considered fire prone and are dominated by deciduous broadleaved species such as Q. petraea and Castanea sativa, respectively. The results indicate that fire affects the soil properties of the various communities in a different manner. Burned sites in the Q. coccifera community have a significantly lower concentration of organic matter, total nitrogen, and available magnesium. At the same time, they have a significantly higher concentration of sand particles and a lower concentration of clay particles. The effect of fire on the soil properties of the other three communities is less dramatic, with differences only in total phosphorus, organic matter, and total nitrogen. The results are discussed in relation to the site conditions and the post-fire regeneration of plant communities.

Vegetation recovery drivers at short-term after fire are plant community-dependent in mediterranean burned landscapes

On the Factor Light in Plant Communities and its Importance for Matter Production

Peri-urban plant communities perform key ecological functions. However, the integrity of peri-urban vegetation is threatened by the continuous expansion of built-up areas and anthropogenic activities, which result in low-intensity, but continuous and pervasive chronic anthropogenic disturbances (CADs). Despite the growing attention to the ecological role of peri-urban vegetation patches, the assessment of the relationship between CADs and typical Mediterranean plant communities at the local scale is still lacking. In this work, both the compositional and functional responses to typical CADs of five vegetation types were assessed in 48 plots, located around the city of Genoa (Italy). The main anthropogenic and environmental drivers of species composition were identified through a Non-Metric Multidimensional Scaling, and selected variables were used to fit a partial Redundancy Analysis. Differences in the number of alien species in relation to total CAD intensity were assessed with a Kruskal-Wallis test. Regarding functional composition, the community weighted mean values (CWMs) of five functional traits were computed for each plot. Generalized linear models were then fitted to assess the relationship between the CWMs and CADs intensity. Our results showed that the specific composition of peri-urban plant communities of Genoa is shaped by interacting environmental and anthropogenic factors. Considering composition, CADs promote the increase of alien species’ number. Moreover, the increased intensity of CADs altered the functional composition, with increasing specific leaf area, leaf nitrogen content and seed bank longevity. Overall, the effect of typical Mediterranean CADs is more pronounced on the functional composition than on the taxonomic composition of peri-urban plant communities. This work highlights the relevance at the local scale of the typical CADs of the Mediterranean area in influencing the different vegetation types that characterise a peri-urban zone.

Plant community is a significant content in the ecosystem. Traditional investigation method for plant community is mainly based on field sampling, which is limited by the data acquisition from complex terrain areas. In contrast, high-resolution remote sensing technique provides a convenient way to quickly access data in a large area. higher dimensional information is needed to distinguish more fine features. To overcome the shortcomings derived from the high dimensional features, which is caused by related data increasing, we choose the algorithm of projection pursuit learning network (PPLN) along with field samples of typical plant communities to realize a fast classification on the vegetation in the east of Shenzhen. Then, in the experiment, the spectral and texture information extracted from Pleiades images, and the terrain interpolated from topographic map are selected and used to build high dimensional features, which is crucial to the vegetation classification using remote sensing images. The learning network for projection pursuit is applied to discriminating the typical communities in both plantation and natural secondary forest in the study area. Compared with Maximum-likelihood classification (MLC) and Support Vector Machine (SVM), PPLN can achieve more accurate results for plant community classification. As a conclusion, the plant community classification with PPLN meets the requirements of the investigation project, achieves the quick updating of some basic information related to forest resources, and looks forward to involve in some other ecological research as well.

Resource Division in an Understory Herb Community: Responses to Temporal and Microtopographic Gradients

This study aimed to identify dominant plant communities across five wet and mesic meadows in the Sierra Nevada Range (California, USA) and examine the impacts of environmental and grazing gradients on plant community distribution and diversity. Species composition and environmental conditions were recorded in 100 plots over two years. Classification and ordination analyses were used to classify plant communities and identify relationships between community types and both environmental and grazing gradients. We identified the following six plant community types: Carex jonesii, Carex leporinella, Carex nebrascensis, Carex utriculata, Eleocharis pauciflora, and Veratrum californicum. We found strong connections between plant communities and water table variables, with low water table (r 2 = 0.56) and mean water table (r 2 = 0.30) significantly correlated with Axis 1 while high water table (r 2 = 0.29) and elevation were correlated with Axis 3 (r 2 = 0.49). We found significant differences among community types for all three water table variables and for elevation. We found no correlation between grazing and community type classification, but there was a significant difference in grazing levels among community types. The plant communities and relationships to water table found in this work may aid managers in understanding present conditions and identifying future changes in meadow ecosystems.

Dividing a rice plant community, which had 7.1 leaf area index with straight and errect leaves, into two communities, one was a plant community with straight and errect leaves which was not treated at all and the other was a plant community with curved and drooped leaves which was made artificially by putting a small weight on the tip of every leaf of the plant community, the author & examined the relation of the rate of carbon assimilation to light intensity on the two plant communities. 1) In the plant commuity with straight and errect leaves the rate of carbon assimilation increased with light intensity and no light saturation point seemed to be found, while in the plant community with the curved and drooped leaves the rate of carbon assimilation increased with light intensity up to about 0.6 cal/cm2. min., but did not increase at all in higher light intensities than 0.6 cal/cm2. min. which seemed to be a light saturation point (Fig. 1-2). 2) As a result of comparing the structures of the two plant communities with each other after Monshi et Saeki, it was made clear that in the plant communities with straight and errect leaves all the leaves are near equally distributed in vertical direction and the sunlight seemed to penetrate fairly well to leaves in the lower layer, while in the plant community with curved and drooped leaves the leaves mostly distributed on the upper layer and the sunlight hardly penetrated in to lower leaves (Fig. 3). 3) For clarifying the reason why the light-curve of carbon assimilation changed with the change of plant type of the communities, an investigation was made on the light-receiving degree of all individual leaves in the two plant communities. The results suggested that in the community with straight and errect leaves the light-receiving degree increased with an increase of the sunlight intensity on most leaves synchronously and progressively, and consequently no light saturation point was found on its light-curve of carbon assimilation, while in the community with curved and drooped leaves the light receiving degree increased with an increase of the sunlight intensity only on a small number of leaves in the uppermost layer of the community and it attained more than a saturation light intensity, but it hardly increased on most leaves with an increease of the sunlight intensity, and consequently a light saturation point was found on the light-curve of carbon assimilation (Fig. 4). 4) The plant community with curved and drooped leaves was less by 34 % in the incresed weight of drymatter in the period after heading and also was less by 33 % in grain yield than that of the plant community with straight and errect leaves, respectively. 5) From the above mentioned facts it was concluded that the rice plant community with straight and errect leaves was one of the most necessary characteristics for maximizing the yield of rice.

Anthropogenic climate warming affects plant communities by changing community structure and function. Studies on climate warming have primarily focused on individual effects of warming, but the interactive effects of warming with biotic factors could be at least as important in community responses to climate change. In addition, climate change experiments spanning multiple years are necessary to capture interannual variability and detect the influence of these effects within ecological communities. Our study explores the individual and interactive effects of warming and insect herbivory on plant traits and community responses within a 7-year warming and herbivory manipulation experiment in two early successional plant communities in Michigan, USA. We find stronger support for the individual effects of both warming and herbivory on multiple plant morphological and phenological traits; only the timing of plant green-up and seed set demonstrated an interactive effect between warming and herbivory. With herbivory, warming advanced green-up, but with reduced herbivory, there was no significant effect of warming. In contrast, warming increased plant biomass, but the effect of warming on biomass did not depend upon the level of insect herbivores. We found that these treatments had stronger effects in some years than others, highlighting the need for multiyear experiments. This study demonstrates that warming and herbivory can have strong direct effects on plant communities, but that their interactive effects are limited in these early successional systems. Because the strength and direction of these effects can vary by ecological context, it is still advisable to include levels of biotic interactions, multiple traits and years, and community type when studying climate change effects on plants and their communities.