نوع مقاله : علمی- پژوهشی
نویسندگان
1 نویسنده مسئول، دانشیار، گروه علوم و مهندسی جنگل، دانشکده منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس، تهران، ایران
2 دانشجوی کارشناسی ارشد، گروه علوم و مهندسی جنگل، دانشکده منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس، تهران، ایران
3 استادیار، باغ اکولوژیک نوشهر، مؤسسه تحقیقات جنگلها و مراتع کشور، تهران، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Vegetation classification is an effective tool for understanding ecological relationships among species, aiding in the planning, monitoring, and management of forest ecosystems. Until now, such studies in Northern Iran have been limited to the deciduous temperate forests of the northern slopes of the Alborz range and the juniper forests in the Firouzkouh Valley on the southern slopes. However, juniper is expanding in some east-west valleys of the Haraz River (specifically, the Siah Beisheh and Punjab Amol regions), adjacent to the deciduous broadleaf Hyrcanian forests, where it forms distinct plant communities. This study presents, for the first time, an ecological classification of Crimean juniper (also known as Greek juniper, Juniperus excelsa M. Bieb.) forests in Haraz Valley (Amol County, northern Iran), located on the northern slope of the Alborz Mountains.
Methodology: A total of 54 sample plots, each 400 m², were established based on the principle of representative stands. Within each plot, all vascular plant species were visually identified and their percent cover estimated using the ordinal van der Maarel cover-abundance scale. Floristic classification was conducted using TWINSPAN based on vegetation cover, and indicator species analysis was performed using the incidence-based phi fidelity method in JUICE software. Differences in ecological units or plant communities based on topographic characteristics were analyzed using one-way ANOVA followed by Duncan post-hoc tests.
Results: Five ecological units or plant communities were identified based on distinct floristic composition and topographic properties: (1) Crimean juniper-Caucasian oak (J. excelsa-Quercus macranthera Fisch. & C.A.Mey.); (2) Crimean juniper-Horned sainfoin (J. excelsa-Onobrychis cornuta (L.) Desv.); (3) Crimean juniper-Judas tree (J. excelsa-Cercis siliquastrum L.); (4) Crimean juniper-common yellow jasmine (J. excelsa- Chrysojasminum fruticans (L.) Banfi); and (5) Crimean juniper-Alder buckthorn (J. excelsa-Rhamnus pallasii Fisch. & C.A.Mey.). The J. excelsa-Q. macranthera group (group 1), due to its association with European-Siberian indicator species, represents a bioclimatic vegetation type on the northern slopes of the Lehar region (Punjab). The J. excelsa-J. fruticans (Group 4) and J. excelsa-C. siliquastrum (Group 3) communities are indicative of Mediterranean climatic conditions in the Siah-Bisheh and Tara regions. Meanwhile, the J. excelsa-O. cornuta (Group 2) and J. excelsa-R. pallasii (Group 5) groups, which also occur on the southern slopes of the Alborz, represent elements of the Iran-Turanian climate in the northern profile.
Conclusion: The findings highlight that Crimean juniper in Haraz Valley is associated with Mediterranean indicator species such as C. siliquastrum, Spiraea crenata L., C. fruticans, Cotoneaster integerrimus Medik., Paliurus spina-christi Mill., Asparagus officinalis L., and Clematis orientalis L., forming several distinct plant communities. The presence of Mediterranean elements, along with some European-Siberian bioclimatic indicators, such as Acer monspessulanum L., A. campestre L., Zelkova carpinifolia (Pall.) K. Koch, Celtis caucasica Willd., and Q. macranthera, emphasizes the marked contrast between J. excelsa communities on the northern and southern slopes of the Alborz. These differences underline the need for greater conservation efforts focused on these newly identified plant communities.
کلیدواژهها [English]
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