بررسی فلور منطقۀ حفاظت شدۀ هزار جریب (واقع در استان‌های مازندران و سمنان)1

منطقه حفاظت شدۀ هزار جریب در ارتفاعات البرز قرار دارد. یکی از مناطق غنی از لحاظ پوشش گیاهی و ناحیه گذر بین دو گستره رویشی هیرکانی و ایران - تورانی محسوب می‌شود. منطقه مورد مطالعه قسمتی از پارک ملی پابند است که در دو استان مازندران و سمنان قرار دارد. نمونه‌های گیاهی طی سال‌های (1389-1388) و (1400-1399) در فصول رویشی مختلف جمع‌آوری و بر اساس روش‌های مرسوم تاکسونومی گیاهی و با استفاده از منابع علمی معتبر شناسایی شدند. در این مطالعه 369 آرایه از 323 گونه جمع‌آوری شدند که به 61 تیره و 226 سرده تعلق دارند. در بررسی این منطقه مشاهده شد دولپه‌ای‌ها با 309 آرایه (%82.6) بزرگترین گروه و تک‌لپه‌ای‌ها با50 آرایه (%13.3) در رده دوم قرار گرفتند. تیره‌های با بیشترین تعداد گونه عبارت اند از: تیره کاسنیان (51 گونه)، تیره نعنائیان (33 گونه)، تیره گندمیان (28 گونه)، تیره گل‌سرخیان (25 گونه) و تیره کلمیان (24 گونه) که از این میان گیاهان تیره گل‌سرخیان علاوه بر فراوانی در تعداد آرایه، پراکنش بسیار وسیعی در منطقه دارند. از کل نمونه‌های جمع آوری شده 39 گونه اندمیک ایران است و 24 گونه با خطر نابودی کم، 3 گونه آسیب پذیر و 23 سرده تک گونه‌ای شناخته شدند. نتایج حاصل از بررسی اشکال زیستی نشان‌دهنده‌ی غالب بودن همی‌کریپتوفیت‌ها (%37.1) به جهت کوهستانی بودن منطقه و در درجه بعدی تروفیت‌ها (%31.2) می‌باشد. همچنین از لحاظ کورولوژی، 230 گونه و یا %62.5 از گونه‌ها به ناحیه ایران - تورانی یا اروپا - سیبری و یا به هردو ناحیه تعلق دارند.

study of the natural flora of hezar-jarib protected area (located in mazandaran & semnan provinces, iran)

hezar-jarib protected area is situated in the heights of the alborz mountains, representing a region of significant botanical richness and serving as a transitional zone between the hyrcanian and iran-turanian (it) vegetation areas. this area is a component of the paband national park, spanning across mazandaran and semnan provinces. plant specimens were gathered during the periods of 2009-2010 and 2021-2022 across various growing seasons and were identified by using traditional methods of plant taxonomy with reference to botanical literature. this study documented 369 taxa of 323 species, encompassing 61 families and 226 genera. dicotyledons constituted the largest group with 309 taxa (82.6%) followed by monocotyledons with 50 taxa (13.3%). the most abundant families were asteraceae (51 species), lamiaceae (33 species), poaceae (28 species), rosaceae (25 species), and brassicaceae (24 species), which exhibited extensive distribution within the region. among the collected samples, 39 species were found to be endemic to iran with 24 species classified as having a low risk of extinction, 3 species as vulnerable, and 23 species as single-species genera. the study’s analysis of life forms revealed the prevalence of hemi-cryptophytes (37.1%) due to the mountainous terrain followed by trophites (31.2%). furthermore, in terms of chorology, 230 species (62.5%) were identified as belonging to the iran-turanian (it) region, the europe-siberian (es) region, or both.introductionthe rich diversity of flora and vegetation in iran can be attributed to its extensive history of vegetation and its inherent evolutionary potential. the significant variations in altitude, humidity, temperature, as well as fluctuations in rainfall and soil conditions across the country have contributed to the creation of a remarkable array of diversity and richness in its plant life. situated in the heights of the alborz mountains, hezar-jarib protected area is recognized as a region abundant in vegetation and serves as a transitional zone between the hyrcanian and iran-turanian (it) vegetation areas. this area is encompassed within the paband national park, spanning across the provinces of mazandaran and semnan.  materials & methodsto conduct a floristic study of hezar-jarib protected area, initial preparations involved obtaining maps of the area from the natural resources organization of neka city, mazandaran province. these maps, along with available software, were utilized to analyze the topography and geography of the region, delineate its boundaries, and subsequently conduct a comprehensive on-site survey. plant specimens were systematically collected during the periods of 2009-2010 and 2021-2022, spanning various growing seasons, and were identified using established methods of plant taxonomy and reputable scientific sources.the sampling process spanned 57 days within the study area, during which comprehensive photographic documentation of all specimens in their natural habitat was undertaken. subsequently, the collected samples were transported to the herbarium botanical laboratory of kharazmi university (t) for drying. following preparation and cleaning, each sample was affixed to specialized cardboard mounts. the specimens gathered during this study are currently housed in the herbarium of kharazmi university. research findingsthe findings from hezar-jarib protected area revealed notable variations in vegetation, encompassing herbal structure and floristic composition, across a moisture gradient. this transition ranged from forested terrain in the north to shrubland and bushland in the central regions, culminating in a desert landscape in the southern slope. plant geography analysis confirmed this transition, delineating the shift from the europe-siberian (es) region in the northern slope to the iran-turanian (it) region in the southern slope with the intermediate zones exhibiting an ecotone rich in species from both vegetation areas.this study documented 369 taxa of 323 species, representing 61 families and 226 genera. dicotyledons emerged as the predominant group, comprising 309 taxa (82.6%) followed by monocotyledons with 50 taxa (13.3%). the most abundant families included asteraceae (51 species), lamiaceae (33 species), poaceae (28 species), rosaceae (25 species), and brassicaceae (24 species). these families not only exhibited high taxonomic diversity, but also demonstrated extensive distribution within the studied area. discussion of results & conclusionthe analysis of life forms revealed the prevalence of hemi-cryptophytes (37.1%) in the region attributed to its mountainous terrain followed by trophites (31.2%). the northern slopes exhibited a decrease in comphytes and an emergence of phanrophytes, indicating the relatively humid climate of this area. the substantial presence of cryptophyte plants, particularly of the geophyte type, suggested deep soil and relatively low soil erosion within the region. in terms of chorology, 6.2% of the species in the region exhibited a global distribution (sosm), while 11% of the species had a wide distribution (pl). notably, plant species from the iran-turanian (it) and european-siberian (es) regions demonstrated extensive distribution within the studied area. specifically, 230 species, constituting 62.5% of the total, belonged to either the it region, the es region, or both.