Plant biodiversity of Hyrcanian relict forests, N Iran: an overview of the flora, vegetation, palaeoecology and conservation.
Plant biodiversity of Hyrcanian relict forests, N Iran: an overview of the flora, vegetation, palaeoecology and conservation.
复制标题
伊朗北部希尔卡尼亚遗迹森林的植物生物多样性：植物区系、植被、古生态和保护概述。
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
Elias Ramezani
中科院分区：
文献类型：
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作者：
H. Akhani;M. Djamali;A. Ghorbanalizadeh;Elias Ramezani
Hyrcanian森林从阿塞拜疆共和国的Talish延伸到伊朗北部的Alborz山脉的北方斜坡，位于吉兰、马赞达兰和戈莱斯坦省。植被主要由落叶林组成。在低海拔地区，它以一些残留的北极第三纪嗜热物种为代表，如Parrotia persica，Gleditsia caspica，Zelkova carpinifolia和Pterocarya fraxinifolia。树种的多样性增加，在海拔较高的亚高山森林和灌木林低灌木林线被取代的高山草原在北方斜坡和伊朗-Turanian刺垫草原在暴露的首脑会议和南坡。迄今为止，伊朗北方省和阿塞拜疆共和国Talish省已报道了3234种，隶属于148科856属。Hyrcanian森林区的主要植被类型包括：i）里海沿岸沿着的沙丘植被; ii）岩石露头上以C4为主的草群落; iii）湿地上的水生植被; iv）河流和山谷森林; v）冲积和低地落叶林; vi）山下和山地落叶林; vii）亚高山落叶林（Quercus macranthera）; viii）演替和过渡灌丛和林地; ix）Cupressus sempervirens和崖柏林地; x）杜松林地; xi）亚高山和高山草甸; xii）以旱生和刺垫物种为主的山地草原; xiii）岩石悬崖群落; xiv）盐生植物群落;十五）蒿属spicigera草原和沙漠一样的沙丘;十六）杂草生境和十七）文化景观和人工林。对伊朗北方黄土/古土壤序列、里海海平面长期波动和泥炭/湖泊沉积物的研究证据表明，南里海地区的气候和植被历史。根据这些调查，在早更新世，至少部分地区被草原状植被覆盖，气候比今天略温暖。据推测，北方伊朗是一个广泛的地区，增加灰尘积累和黄土形成在更新世冰期，这是同期和类似的主要气候变化在东南中欧和中亚。这些研究进一步表明，该国北部的气候发生了明显的变化，在更新世冰期期间，干燥和凉爽的气候变成了潮湿和温暖的条件。同样，一个显着的干燥期发生在全新世早期的南里海地区，平行于欧洲的气候最佳。孢粉学研究还表明，在过去的几个世纪里，人类活动对该地区的低地森林组成和结构产生了更大的影响。里海南部地区的森林严重退化和被砍伐，特别是在冲积低地，那里只存在少量残余物。阿尔博尔兹山脉和里海南部地区有几个保护区管理不善。因此，提高其保护质量，增加其面积或增加新的地点是至关重要的，以确保保护这一非常重要的自然遗产的西南亚。
The Hyrcanian forests stretch from Talish in Republic of Azerbaijan and cover the northern slopes of the Alborz Mountains in North Iran, in Gilan, Mazandaran and Golestan provinces. The vegetation is composed mostly of deciduous forests. In the lower altitudes it is represented by a number of relict Arcto-Tertiary thermophilous species such as Parrotia persica, Gleditsia caspica, Zelkova carpinifolia and Pterocarya fraxinifolia. The diversity of tree species increases at higher elevations where the subalpine forests and scrubs of low shrubs of the timber-line are replaced by alpine grasslands in the northern slopes and the Irano-Turanian thorn-cushion steppe at the exposed summits and southern slopes. So far, 3234 species belonging to 856 genera and 148 families of vascular plants have been reported from the northern provinces of Iran and Talish in the Republic of Azerbaijan. Main vegetation types of the Hyrcanian forest zone include: i) sand dune vegetation along the Caspian Sea coasts; ii) C4-dominated grass communities on rocky outcrops; iii) aquatic vegetation on wetlands; iv) riverine and valley forests; v) alluvial and lowland deciduous forests; vi) submontane and montane deciduous forests; vii) subalpine deciduous forests (Quercus macranthera); viii) successional and transitional scrub and woodlands; ix) Cupressus sempervirens and Thuja orientalis woodlands; x) juniper woodlands; xi) subalpine and alpine meadows; xii) montane steppe dominated by xerophytic and thorn-cushion species; xiii) rock cliff communities; xiv) halophytic communities; xv) Artemisia spicigera steppe and desert like dunes; xvi) ruderal habitats and xvii) cultural landscapes and artificial forests. Evidence from studies on loess/palaeosol sequences, long-term Caspian Sea-level fluctuations, and peat/lake deposits in northern Iran give some indication of the climate and vegetation history of the south Caspian region. Based on these investigations, during the early-Pleistocene, at least parts of the area were covered by steppe-like vegetation and the climate was slightly warmer than today. It is also postulated that northern Iran was an extensive area of increased dust accumulation and loess formation during the Pleistocene glaciations, which is contemporaneous with and similar to major climatic changes as in SE Central Europe and Central Asia. These studies further suggest pronounced climate changes for the north of the country in which a dry and cool climate changed to moist and warm conditions during the Pleistocene glaciations. Similarly, a markedly dry period occurred during the early Holocene for the south Caspian area, parallel to the climatic optimum in Europe. Palynological studies have also shown intensified human impact on the lowland forest composition and structure of the area over the last centuries. The forests of the south Caspian area are severely degraded and deforested; in particular, in the alluvial lowlands where only small remnants exist. There are several protected areas in the Alborz Mountains and south Caspian area which suffer from mis-management. Therefore, improving their protection quality and increasing their area or addition of new sites are crucial to guarantee conservation of this very important natural heritage of SW Asia.