The assignment of relev?s to pre-existing vegetation units: a comparison of approaches using species fidelity
Hamed Asadi, Omid Esmailzadeh, Miquel De C?ceres, Seyed Mohsen Hosseini
Journal PapersAnnals of Forest Science , Volume 78 , Issue 1, 2021 March , {Pages 23-Jan }
Abstract
• AimsThe main aims were to evaluate the relative predictive performance of different statistical fidelity measures for the reassignment of relev?s to existing vegetation units, and in which cases reassignments improve the quality of the original classification.• MethodsWe took the classifications produced by three commonly used unsupervised classification methods, and all relev?s were reassigned to the closest vegetation unit according to the total fidelity value index (TFVI), where fidelity value had been calculated using one of eight distinct statistical measures, and according to the frequency-positive fidelity index (FPFI). Classifications obtained after relev? reassignments were compared to the initial ones using the Adjusted Rand
Evaluating the different indicator species analysis in the classification of plant communities
BG Saberi, O Esmailzadeh, H Asadi
Journal PapersIranian Journal of Forest , Volume 12 , Issue 4, 2021 February 19, {Pages 541-555 }
Abstract
The goal of this study is to evaluate the quality of numerical methods (Phi fidelity and indicator value indices) and non-statistical (constancy ratio and total cover ratio indices) in determining the indicator species of Beech plant communities in the eastern Hyrcanian forests. For this purpose, six ecological groups were first classified using two-way indicator analysis or TWINSPAN. Then, by using sum of the indicator value/association indices or TFVI, as a similarity index for assignment of the plot to the plant communities, with emphasizing the result of species and plant communities association (based on 10 algorithms), the groups were reclassified. Evaluating the compatibility of the results of each classification algorithms with the
Classification of forest communities (co-) dominated by Taxus baccata in the Hyrcanian forests (northern Iran) and their comparison with southern Europe
P Karami-Kordalivand, O Esmailzadeh, W Willner, J Noroozi, SJ Alavi
Journal PapersEuropean Journal of Forest Research , 2021 January 3, {Pages 14-Jan }
Abstract
English yew (Taxus baccata) is one of the few gymnospermous species present in the Hyrcanian forests, and it is listed as a rare and endangered species prone to extinction in Iran. This study aims to determine the ecological capability of Taxus baccata in the Hyrcanian region by identifying the diversity of plant communities dominated by this species, and to compare their floristic composition with the Taxus communities of southern Europe (Sicily, Corsica, Sardinia). We collected 408 relev?s in the central and eastern part of the Hyrcanian forests. The classification of plant communities was performed using TWINSPAN. Phi-coefficient index, constancy ratio, and the ratio of average cover were used to determine diagnostic species
Optimizing the classification of species composition data by combining multiple objective evaluators toward selecting the best method and optimum number of clusters
Classification is an appropriate tool for the summarizing of species data in community ecology. Researchers need to select the effective classification method (s) and the optimum number of clusters to perform a reasonable classification. The aims of the present research are to assess the efficacy of various classification algorithms and to select the optimum number of clusters. We used a dataset of 197 400-m2relev?s recorded from TarbiatModares University research forest located in the north of Iran. For each relev?, a species list and the canopy cover were recorded by using Braun-Blanquet cover-abundance scale modified by van der Maarel. We considered seven classification methods: flexible-β linkage (β=-0.25), Ward\\\\\\\\\\\\\\\'s linka
The Hyrcanian Forests, well-known for its World Heritage site in the South Caspian region of Northern Iran, are refugia for a special tree flora. Some areas in particular feature a concentration of large and numerous trees of Taxus baccata, a species that has attracted the interest of many researchers given its medicinal importance. The objective of this study was to analyze the biological and structural features of these unique ecosystems based on three large tree-mapped field plots using new methods. We developed a species abundance distribution and three species–area relations, and analyzed the small-scale structural patterns of each of the 15 tree species that occur in the plots. Species-specific details are presented for each of the
Zarde-Kija mushroom (Cantharellus alborufescens) is one of the edible mushrooms belong to the Cantharellaceae family. It is widely distributed in the northern forests of Iran and is desirable for local residents in these areas. Despite the economic importance of this genus, litthe is known about their habitat requirements. This study was conducted to identify the environmental factors affecting the distribution of this mushroom in a plain forest of Noor city (Mazandaran province, northern Iran) with 120 ha area. For this purpose, 20 pair plots (20 m? 20 m) with at least 100 m distance were established (20 plots with Cantharellus and 20 non-Cantarellus plots). To analyze the speciesenvironment relationship (soil characteristics), three group
Diversity and Gradient Analysis of Common Yew (Taxus Baccata L.) Communities in Eastern Hyrcanian Forests, Northern Iran
Omid Esmailzadeh, Meysam Soofi, Pari Karami
Journal Papers , 2020 August 7, {Pages }
Abstract
Aims: To outline syntaxonomical synthesis of yew (Taxus baccata L.) in the eastern of Hyrcanian forest and to identify their main environmental gradients.Location: Jahan-Nama protected area (JNPA) as a unique yew population with heterogeneous oristically composition in the east of Hyrcanian forests, Northern Iran.Methods: Vegetation units were classi ed using modi ed TWINSPAN and were translated into syntaxonomic system. Syntaxa were determined by re-arrangement of each relev? based on diagnostic species occurrences and expert knowledge with the aim to increase the oristic distinctiveness of vegetation units. Syntaxa were nally evaluated by diagnostic species and environmental parameters according to phi-values and ANOVA, respectively. DCA
The Increase in studies of beta diversity has led to several measures and methods. The variety of theses indicators cause their use in confusion. The aim of this study was to evaluate and determine the relationships between 18 different beta diversity indices based on presence and absense data. For this purpose, Buxus hyrcana database in Golestan and Mazandaran provinces was used. Clustering results showed that these 18 indices classified into 4 distinct groups with similar performance. Evaluation of clustering results by Detrended correspondence analysis (DCA) analysis showed that the indices of the four groups of cluster analysis can be separated into three distinct groups. From basis of combined results of discriminant analysis and Braun
Persian Silk tree (Albizia julibrissin Durazz.) is one of the native leguminous species in plain and lowland hyrcanian forests, which has been severely damaged by fungal disease. In this research, feasibility of preservation of A. julibrissin seeds in cryo condition was studied. Seeds of A. julibrissin were collected from 10 trees in lowland forests of western part of Haraz watershed, Mazandaran province, Iran. Seed germination characteristic of this species were analyzed in cryopreservation with four pretreatments including: vitrification solutions, 30% glycerol, desiccation and without cryoprotectants as well as control treatment, storage in dry condition at 15 C temperature. Seeds after one week and one month storage in liquid nitrogen c
In this research, the application of Artificial Neural Network or MLP method in the process Assignment of relev?-groups/plant communities allocation was evaluated using Buxus hyrcana forests database. For this purpose, firstly, the ecological and sociological groups of B. hyrcana were determined using TWINSPAN and Braun-Blanquet method, respectively. The results of both numerical and expert based classification dendrogram of the B. hyrcana communities, which included seven levels of classification as primary groups/plant communities, were introduced to MLP. Then, with assignments in three sets of training (70%), test (15%) and validation (15%), the MLP classification was performed on each level of the two dendrograms. The results showed tha
Understanding the underlying mechanisms for tree species regeneration, as well as the positive and negative interaction between tree species and regeneration can improve the effectiveness of forest management and restoration activities. English yew, as one of the rare and valuable native species in Hyrcanian forests, Iran, has declined over the past several decades for many reasons such as lack of regeneration in existing populations. This research aims at studying the spatial pattern of English yew regeneration and its interaction with adult trees. For this purpose, the location of all English yew trees and its regeneration was recorded using TP360 device and distance-azimuth method in the Afratakhteh Forest Reserve, Golestan province. Tot
Analyzing the ecological niche of Buxus hyrcana Pojark in relation to some environmental variables in the northern forests of Iran
S Habibi Kilak, SJ Alavi, O Esmailzadeh
Journal PapersForest and Wood Products , Volume 72 , Issue 1, 2019 May 22, {Pages 21-31 }
Abstract
By determining the environmental factors affecting the plant species in a particular site, the presence of the species in the site can be predicted. The aim of this study was to investigate the response of Buxus to environmental variables individually and to extract its ecological optimum and amplitude in relation to the most important environmental factors using HOF function. This study has been done in the major sites of Buxus hyrcana in the Hyrcanian forests. 834 sample plots (400 m2) were established by systematic-selective method and within each plot, the presence of this species, topographic factors and some soil variables were recorded and measured. Fitting the response curve to the environmental variables with HOF function showed th