Classification of the Hyrcanian forest vegetation, Northern Iran

Abstract

AimsTo develop forest vegetation classification at the level of alliances and associations across the Hyrcanian ecoregion, Northern Iran, and to explore the effects of main environmental and geographic gradients on their distribution.LocationHyrcanian ecoregion, Northern Iran.MethodsA database of 1,597 vegetation plots of mostly 400 m2 in size with a total of 802 vascular plant taxa was established, covering the whole geographic range of the Hyrcanian forests at altitudes ranging from −22 to 2,850 m a. s. l. An expert system was developed for automatic classification of vegetation plots into alliances and associations. Detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to determine the most important environmental and geographic gradients affecting species composition.ResultsTwenty‐one associations and seven alliances of these forests, belonging to five orders and four classes, were defined. Among them, eleven associations and five alliances were described as new syntaxa. Alnion glutinosae and Smilaco excelsae‐Alnion barbatae, both distributed in the lowland belt, include swamp and wet forests, respectively. Parrotio persicae‐Carpinion betuli and Alnion subcordatae are respectively mesic and wet forests of the submontane belt. Solano kieseritzkii‐Fagion orientalis is a mesic beech forest in the montane belt, and finally, Quercion macrantherae, an open oak forest, and Centaureo hyrcanicae‐Carpinion orientalis, a dry hornbeam forest, occur in the upper‐montane belt. DCA and CCA analyses showed that the distribution of these alliances and associations is mainly related to altitude and mean annual temperature.ConclusionsBased on our results and comparison between the Hyrcanian and European forests, we propose a new, comprehensive syntaxonomic scheme for the Hyrcanian forests, supported by a classification expert system. Unlike previous studies, we linked the classification system to that of EuroVegChecklist because, though this area is outside of Europe, its vegetation is very similar to that of the European temperate forest vegetation.

The relationship between niche breadth and range size of beech (Fagus) species worldwide

“…Fagus hayatae has a very disjunct distribution with two subranges in mainland China and Taiwan Island, and thus, covers a broad, yet disjunct range of climatic conditions (Hukusima et al, 2013;Shen, 1992;Shen et al, 2015). Fagus orientalis, although with a distinctly narrower range size compared to F. grandifolia and F. sylvatica, covers diverse climatic zones from the Balkan mountain ranges to the southern Euxinian, Colchic, Eastern Mediterranean and Hyrcanian regions (Crimea, North Turkey, Caucasus, isolated patches in southern Turkey and North Iran), in combination with steep elevational gradients (Gholizadeh et al, 2020;Kavgaci et al, 2012;Shen, 1992). For example, in the Hyrcanian area, F. orientalis grows between around 300 to 2700 m a.s.l., covering a broad range of climatic conditions (from warm and humid to cool and dry) (Gholizadeh et al, 2020).…”

A classification of woody communities based on biological dissimilarity

“…Based on the Bray–Curtis dissimilarity (Figure 7b), the Iranian plot is more related to the temperate forests of China. These results are interesting, because the Hyrcanian forests of Iran represent a transitional formation with floristic elements from both Europe and Asia (Gholizadeh et al, 2020).…”

Formalized Hierarchically Nested Expert System for Classification of Mesic and Wet Grasslands in Poland

“…The majority of the previously proposed ES for classification of various types of vegetation enabled the assignment of relevés at one level only, most often at the association or alliance level. There are only a few examples of ES that were created for classification of at least two hierarchical levels (Gholizadeh et al, 2020;Janišová & Dúbravková, 2010;Landucci et al, 2020;Swacha et al, 2016). The necessity of developing an ES that includes definitions of syntaxa representing all principal hierarchical levels is needed considering that a relatively large portion of vegetation plots could not be classified at the association level.…”

“…The philosophy of the Braun-Blanquet approach has been partly met by the hierarchical expert system representing a two-level, formalized classification of rocky Pannonian grasslands and dealpine Sesleria-dominated grasslands in Slovakia (Janišová & Dúbravková, 2010). This approach was also successfully used to classify Molinia grasslands in Poland (Swacha et al, 2016) and the Hyrcanian forest vegetation in Northern Iran (Gholizadeh et al, 2020). A two-level hierarchically nested system was also performed using fuzzy clustering (Wiser & De Cáceres, 2018).…”