ارزیابی موفقیت عملیات اصلاحی کاشت آنغوزه در مراتع نیمه‌استپی با مرتبط کردن صفت‌های کارکردی به تنوع گونه‌ای

اصلاح بوم‌ سازگان ‌ها زمانی موفقیت‌آمیز است که گونه‌ های باارزش در جوامع گیاهی شانس توسعه پیدا کنند. در اصلاح بوم‌ سازگان ‌ها از طریق کشت یک گونه این امر بیشتر اهمیت دارد زیرا با افزایش یک گونه، ارتباط بین گونه ‌ها تغییر بیشتری می‌ کند. هدف از پژوهش حاضر، ارزیابی موفقیت عملیات اصلاحی کاشت آنغوزه در مراتع نیمه‌استپی با استفاده از ارتباط صفت‌ های کارکردی و تنوع گونه‌ای است. دو منطقه شامل منطقۀ قرق کپه‌ کاری شده با گیاه آنغوزه و منطقۀ شاهد انتخاب و در هر یک، سه ترانسکت m100 مستقر شد. در امتداد هر ترانسکت، 10 پلات m21 مستقر و متغیرهای درصد تاج پوشش و تراکم گونه‌ های گیاهی تعیین شد. صفت ‌های عملکردی (طول عمر، خوشخوراکی، فرم رویشی، فرم زیستی، طول عمر برگ، عمق ریشه‌دوانی، چوبی بودن، آغاز گلدهی، طول دوره گلدهی، ارتفاع و تراکم ساقه) نیز برای هر گیاه اندازه‌ گیری شدند. تجزیه‌وتحلیل مولفه اصلی برای خلاصه کردن ارتباط صفت‌ های عملکردی گیاه و مدیریت بوم ‌سازگان بکار برده شد. برای ارزیابی رابطه بین صفت ‌های عملکردی گیاهان و تنوع گونه‌ای از مدل معادلات ساختاری استفاده شد. نتایج نشان داد که آنغوزه به‌طور معنی‌ داری شاخص‌ های تنوع را افزایش داده است (p<0.05). مدل معادلات ساختاری نشان داد که خوشخوراکی مهم ترین صفت عملکردی گیاهان در ارتباط با تنوع در منطقه قرق (مدیریت نشده) بود و گیاهان یک‌ساله غیر خوشخوراک بیشترین اهمیت را در تعیین تنوع گونه‌ ای داشتند. نتایج نشان داد که آنغوزه نقش واسطه‌ گری جزئی در ارتباط بین صفت‌ های عملکردی و تنوع گونه‌ ای دارد. با نقش واسطه‌ گری آنغوزه، فرم رویشی مهم‌ترین صفت عملکردی در ارتباط با تنوع گونه‌ ای بود. همی ‌کریپتوفیت‌ ها، مهم ترین فرم رویشی در ارتباط با تنوع گونه‌ ای بودند که بیانگر موفقیت برنامه اصلاحی کاشت آنغوزه است. ارتباط دادن صفت‌ های کارکردی به تنوع گونه‌ای جهت بررسی موفقیت عملیات اصلاح مرتع، به مدیران برای بررسی نقش واسطه‌ گری گونه ‌های کشت شده بر تغییر ساختار و عملکرد جوامع گیاهی کمک می ‌کند.

assessing the success of ferula assa-foetida l. plantation restoration operations in semi-steppe rangelands by linking plant functional traits to species diversity

extended abstract introductionsuccessful ecosystem restoration requires the reproduction of valuable plant species in the plant community. this is more important for monocultures because the interaction between species changes more with the increase of a species. the planting of native species with highly competitive power is controversial in restoration operations, due to their highly competitive abilities, their dominance and persistence after restoration can make reproduction of other species difficult (9). evaluation of the success of restoration operations has been done using various indicators. to examine the success of restoration operations or the intensity of ecosystem exploitation, species diversity is a suitable indicator (8). margalef richness, simpson diversity, and shannon diversity indices are commonly employed to monitor changes in species diversity (5, 7). by studying the dynamics of plant communities, we can understand how the structure, composition, and function of plant communities respond to restoration operations. plantation is a restoration operation that can have a significant impact on the composition of plant communities. plantation can alter the interaction between species, which can lead to changes in the functioning of the ecosystem. to determine the success of a restoration operation, it is important to select species for plantation in degraded ecosystems, which will lead to the increase of other valuable species. recognizing the success of restoration operations, particularly in plantation, can be achieved by identifying important functional types related to species diversity. thus, this investigation is focused on the objectives listed below: 1) investigating the impact of the plantation of assafoetida on the species diversity in semi-steppe rangelands, 2) identification of important functional traits in relation to species diversity in the degraded areas, and 3) examining the mediation role of assafoetida in the relationship between plant functional traits and diversity. material and methodsthe studied area is located in tang-e sorkh rangelands, 45 km from yasuj city (kohgiluyeh and boyer ahmad province) and has the geographical coordinates of 51˚40’04& to 51˚46’08& e and 30˚22’35& to 30˚27’37& n. due to the implementation of tang-e sorkh multi-purpose project, which aims to ensure continuity and sustainability of the rangeland, assafoetida has been planted in this area. ferula assa-foetida l. is the scientific name of assafoetida. this plant is a significant native plant that grows in the rangelands of iran. to conduct the present research, two areas were selected, including the exclosure area interseted by assafoetida and the control area. three 100-meter transects were laid out in each of the grazed and exclosure areas, according to the features of the area. each transect consisted of ten plots that measured 1 square meter each. each of the grazed and exclosure areas had thirty plots established. the canopy cover and density of plant species were recorded in every plot. functional traits (growth form, life form, palatability, life span, leaf life span, root depth, woodiness, flowering start, length of flowering period, height, and stem density) were measured according to literature (1, 2, 3, 4, 6, 10, 11). the analysis of diversity indices in the grazed and exclosure sites was conducted using a t-test. to summarize the relationship between plant functional traits and ecosystem management, principal component analysis (pca) was employed. structural equation modeling (sem) was used to evaluate the relationship between plant functional traits and diversity. sem was employed to examine how assafoetida mediates the connection between plant functional traits and diversity indices using variance-accounted for (vaf). the vaf parameter is calculated by dividing the indirect effect by the total effect of the variables. results the t-test results showed that the two grazed and exclosure sites had significant differences in terms of simpson, shannon and margalef indices (p<0.05). pca findings showed that the most significant functional traits associated with ecosystem management are growth form, life form, life span, leaf life span, and palatability. the most significant impact on species diversity was due to palatability (p< 0.001). life form had a positive effect on species diversity, while life span and leaf life span had negative effects on species diversity (p< 0.01). however, growth form had no significant impact on species diversity (p>0.05). a vaf of 0.3 was obtained for the mediating role of assafoetida in the relationship between growth forms and diversity indices, suggesting a partial mediating role. according to the findings, the development of assafoetida has had an impact on mutual relationships between species. the success of ecosystem restoration cannot be attributed solely to the improvement in species diversity with the plantation of assafoetida. the technique used to recognize the success of the restoration operations in this study was to increase the number of valuable species in relation to the diversity of species. structured equation modeling allowed for the study of important individual species in vegetation composition with assafoetida’s mediating role. conclusion and discussionour findings showed that assafoetida played a partial mediating role in the relationship between plant functional traits and diversity. exclosure along with the assafoetida plantation has caused the development of valuable species in the vegetation composition. the success of assafoetida plantation in restoring semi-steppe rangelands can be determined by both species’ diversity and plant functional traits.