50 research outputs found

    Late Little Ice Age palaeoenvironmental records from the Anzali and Amirkola Lagoons (south Caspian Sea): Vegetation and sea level changes

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    This is a postprint version of the article. The official published article can be found from the link below - Copyright @ 2011 Elsevier Ltd.Two internationally important Ramsar lagoons on the south coast of the Caspian Sea (CS) have been studied by palynology on short sediment cores for palaeoenvironmental and palaeoclimatic investigations. The sites lie within a small area of very high precipitation in a region that is otherwise dry. Vegetation surveys and geomorphological investigations have been used to provide a background to a multidisciplinary interpretation of the two sequences covering the last four centuries. In the small lagoon of Amirkola, the dense alder forested wetland has been briefly disturbed by fire, followed by the expansion of rice paddies from AD1720 to 1800. On the contrary, the terrestrial vegetation reflecting the diversity of the Hyrcanian vegetation around the lagoon of Anzali remained fairly complacent over time. The dinocyst and non-pollen palynomorph assemblages, revealing changes that have occurred in water salinity and water levels, indicate a high stand during the late Little Ice Age (LIA), from AD < 1620 to 1800–1830. In Amirkola, the lagoon spit remained intact over time, whereas in Anzali it broke into barrier islands during the late LIA, which merged into a spit during the subsequent sea level drop. A high population density and infrastructure prevented renewed breaking up of the spit when sea level reached its maximum (AD1995). Similar to other sites in the region around the southern CS, these two lagoonal investigations indicate that the LIA had a higher sea level as a result of more rainfall in the drainage basin of the CS.The coring and the sedimentological analyses were funded by the Iranian National Institute for Oceanography in the framework of a research project entitled “Investigation of the Holocene sediment along the Iranian coast of Caspian Sea: central Guilan”. The radiocarbon date of core HCGL02 was funded by V. Andrieu (EuropĂŽle MĂ©diterranĂ©en de l'Arbois, France) and that of core HCGA04 by Brunel University

    Diversity of macrophytes and microphytes in an urban wetland, Babol, Mazandaran Province, Iran; toward a conservation policy

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    Despite to its importance for retaining biodiversity and human health, urban wetlands have received much less attention than other wetland types in northern Iran. This study deals with the floristic characteristics of one of the largest urban wetlands in Central Mazandaran, Roshanabad wetland in Babol. All vascular plants were collected during two growing seasons of 2014 and 2015 and water sampling was performed seasonally (autumn 2014 to summer 2015). We encountered 102 plant species belonging to 80 genera and 39 families. The largest families in the studied area were Poaceae with (11.7%) followed by Cyperaceae and Asteraceae (9.8%) and Fabaceae and Polygonaceae (5.9%). Genera represented by the greatest number of species were Cyperus (7 sp.), Polygonum (4 sp.), Ranunculus (3 sp.) and Typha (3 sp.). Classification based on life form, indicated that the therophytes (47%) comprised the largest proportion of the plants in the studied area. From chorological point of view, the largest proportion of the flora belonged to the pluriregional elements (62.3%). Various habitats of the wetland are discussed. Moreover, 63 genera of fresh water algae, belonging to eight phyla were identified in the study area. Cholorophyta with 28 genera was the most abundant phylum followed by Bacillariophyta (19 genera), Cyanophyta (6 genera), Euglenophyta (4 genera), Chrysophyta, Dinophyta (2 genera), and Charophyta, Xanthophyta (each with one genus). Moreover, a comparison between the data as well as ratios of species/genera and genera/families collected from this wetland and from the other wetlands in north Iran has been provided. Roshanabad wetland had fewer aquatic species compared to some other wetlands in north of Iran, because of anthropogenic effects such as penetration of agricultural and urban sewage which has large quantities of nitrate and phosphate, and distribution of exotic aquatic plant, Azolla filiculoides. Moreover, Palmer Index of pollution shows that the wetland has high ratio of pollution in all seasons. This urban wetland site may be considered as a pilot site for the interaction of human effects and biodiversity pool. This is among the first attempts for restoration of such an important and sensitive ecosystem in north of Iran

    Ramsar international wetlands of Alagol, Almagol and Ajigol in eastern parts of the Caspian Sea: A floristic and habitat survey

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    Ramsar international wetlands of Alagol, Almagol and Ajigol with a surface of 3027 ha are located in the vast Turkmen-Sahra plains (Golestan prov.) in east of Caspian Sea and in the vicinity of the Iran-Turkmenistan political border. Flora, vegetation and habitat diversity of the wetlands were surveyed during growing seasons of 2014 and 2015. A total of 159 plant taxa belonging to 123 genera and 42 families were determined in the studied wetlands. Asteraceae, Amaranthaceae (including Chenopodiaceae) and Poaceae were the most species rich families and Suaeda, Salsola, Atriplex, Plantago and Tamarix were the most species rich genera. A floristic analysis indicated that therophytes and pluriregional elements predominated life form and chorological spectra, respectively. Studied sites were physiognomically classified into aquatic, emergent, and dry upland habitats which represent 6, 68 and 26 percent of all plant taxa, respectively. Halophytic species constitute a large part of flora, among them Puccinellia poecilantha recently recorded in the area is considered as a rare plant. The results may be applied in designing conservation areas and developing conservation strategies for this unique wetland ecosystem

    Assessing plant diversity and composition in grasslands across spatial scales: the standardised EDGG sampling methodology

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    This paper presents the details of the EDGG sampling methodology and its underlying rationales. The methodology has been applied during EDGG Research Expeditions and EDGG Field Workshops since 2009, and has been subsequently adopted by various other researchers. The core of the sampling are the EDGG Biodiversity Plots, which are 100‐m2 squares comprising, in two opposite corners, nested‐plot series of 0.0001, 0.001, 0.01, 0.1, 1 and 10 m2 square plots, in which all terricolous vascular plants, bryophytes and lichens are recorded using the shoot presence method. In the 10‐m2 plots, species cover is also estimated as a percentage and various environmental and structural parameters are recorded. Usually the EDGG Biodiversity Plots are complemented by the sampling of additional 10 m2 normal plots with the same parameters as the 10‐m2 corners of the first, allowing coverage of a greater environmental diversity and the achievement of higher statistical power in the subsequent analyses for this important grain size. The EDGG sampling methodology has been refined over the years, while its core has turned out to generate high‐quality, standardised data in an effective manner, which facilitates a multitude of analyses. In this paper we provide the current versions of our guidelines, field forms and data entry spreadsheets, as open‐access Online Resources to facilitate the easy implementation of this methodology by other researchers. We also discuss potential future additions and modifications to the approach, among which the most promising are the use of stratified‐random methods to a priori localise the plots and ideas to sample invertebrate taxa on the same plots and grain sizes, such as grasshoppers (Orthoptera) and vegetation‐dwelling spiders (Araneae). As with any other method, the EDGG sampling methodology is not ideal for every single purpose, but with its continuous improvements and its flexibility, it is a good multi‐ purpose approach. A particularly advantageous element, lacking in most other sampling schemes, including classical phytosociogical sampling, is the multi‐scale and multi‐taxon approach, which provides data that allow for deeper understanding of the generalities and idiosyncrasies of biodiversity patterns and their underlying drivers across scales and taxa

    Past climatic refugia and landscape resistance explain spatial genetic structure in Oriental beech in the South Caucasus.

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    Predicting species-level effects of climatic changes requires unraveling the factors affecting the spatial genetic composition. However, disentangling the relative contribution of historical and contemporary drivers is challenging. By applying landscape genetics and species distribution modeling, we investigated processes that shaped the neutral genetic structure of Oriental beech (Fagus orientalis), aiming to assess the potential risks involved due to possible future distribution changes in the species. Using nuclear microsatellites, we analyze 32 natural populations from the Georgia and Azerbaijan (South Caucasus). We found that the species colonization history is the most important driver of the genetic pattern. The detected west-east gradient of genetic differentiation corresponds strictly to the Colchis and Hyrcanian glacial refugia. A significant signal of associations to environmental variables suggests that the distinct genetic composition of the Azerbaijan and Hyrcanian stands might also be structured by the local climate. Oriental beech retains an overall high diversity; however, in the context of projected habitat loss, its genetic resources might be greatly impoverished. The most affected are the Azerbaijan and Hyrcanian populations, for which the detected genetic impoverishment may enhance their vulnerability to environmental change. Given the adaptive potential of range-edge populations, the loss of these populations may ultimately affect the specie's adaptation, and thus the stability and resilience of forest ecosystems in the Caucasus ecoregion. Our study is the first approximation of the potential risks involved, inducing far-reaching conclusions about the need of maintaining the genetic resources of Oriental beech for a species' capacity to cope with environmental change

    GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands

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    GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (releves) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001;... 1,000 m(2)) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database " sPlot". Its main aim is to facilitate studies on the scale-and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board

    Relationships between Vegetation and Ecological variablesin Palangan Habitat, Aghdagh Protected Area of Ardabil Province

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    Knowledge about plant communities and their relationships with ecological factors is one of the most important issues in conservation ecology particularly in the recent decades. The current investigation aimed to study the vegetation ecology of Palangan habitat in Aghdagh Protected area, Ardabil province. In order to collect species and environmental data, a total of 45 plots along a 1500 m elevational gradient and an interval of 100 m were surveyed. Braun-Blanquet scales were used to evaluate vegetion cover of each plot. Floristic and ecological characteristics of the area were studied along elevational gradient using DCA ordination and TWINSPAN classification methods. Four vegetation groups detremined in TWINSPAN were also identified in the DCA diagram and their species and environmnetal characters have been evalyated by one-way ANOVA. Based on these anlayses, altitude and slope were the most important ecological factors affecting the vegetation of the area. Endemicity values are not significatly changed among different altitudinal belts, but in stead, the number of therophytes and plants with wide distributional ranges are significam,ty different along elevation. The relatiohsip between altitude and species richness, like to other mountainus systems, show almost unimodal pattern which peaks at 1800 m

    Environmental gradients across wetland vegetation groups in the arid slopes of Western Alborz Mountains, N. Iran

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    Mountain wetlands are unique ecosystems in the arid southern slopes of Alborz range, the second largest range in Iran. The spatial distribution characteristics of wetland vegetation in the arid region of the Alborz and the main factors affecting their distributional patterns were studied. A classification of vegetation and ecological characteristics were carried out using data extracted from 430 relevés in 90 wetland sites. The data were analyzed using Two Way Indicator Species Analysis (TWINSPAN) and detrended correspondence analysis (DCA). The wetland vegetation of Alborz Mountain was classified into four large groups. The first vegetation group was calcareous rich vegetation, mainly distributed in the river banks and characterized by helophytes such as Bolboschoenus affinis as indicator species. The second group was saline transitional vegetation, distributed in the ecotone areas and dominated by Phragmites australis. The third vegetation group is wet meadow vegetation which mainly consists of geophytes, endemic and Irano-Turanian species, distributed in the higher altitudes. This vegetation is mainly characterized by indicator species such as Carex orbicularis, high level concentration of Fe2+ and percentage of organic matter in the soil. The fourth vegetation group is aquatic vegetation, distributed in the lakeshores. The aquatic group species are mainly hydrophytic such as Batrachium trichophyllum. The TWINSPAN vegetation groups could be also recognized in the DCA graphs and ecologically differentiated by ANOVA of studied variables. Four vegetation groups can be differentiated on two first axes of indirect ordination. There is a gradient of pH, EC and organic matter associated with altitude on the DCA diagram. Correlation analysis between the axes of DCA and environmental factors shows that altitude, soil texture and other dependant environmental variables (e.g. pH) are the main environmental factors affecting the distribution of wetland vegetation groups
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